Vol. 81 Monday, 

No. 49 March 14, 2016 

Part II 

Department of Transportation 

Federal Aviation Administration 

14 CFR Parts 21, 23, 35, et al. 

Revision of Airworthiness Standards for Normal, Utility, Acrobatic, and 

Commuter Category Airplanes; Proposed Rule 

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13452 Federal Register / Vol. 81, No. 49 / Monday, March 14, 2016 / Proposed Rules 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Parts 21, 23, 35, 43, 91, 121, 

and 135 

[Docket No.: FAA–2015–1621; Notice No. 

16–01] 

RIN 2120–AK65 

Revision of Airworthiness Standards 

for Normal, Utility, Acrobatic, and 

Commuter Category Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to amend 

its airworthiness standards for normal, 

utility, acrobatic, and commuter 

category airplanes by removing current 

prescriptive design requirements and 

replacing them with performance-based 

airworthiness standards. The proposed 

standards would also replace the 

current weight and propulsion divisions 

in small airplane regulations with 

performance- and risk-based divisions 

for airplanes with a maximum seating 

capacity of 19 passengers or less and a 

maximum takeoff weight of 19,000 

pounds or less. The proposed 

airworthiness standards are based on, 

and would maintain, the level of safety 

of the current small airplane 

regulations. Finally, the FAA proposes 

to adopt additional airworthiness 

standards to address certification for 

flight in icing conditions, enhanced stall 

characteristics, and minimum control 

speed to prevent departure from 

controlled flight for multiengine 

airplanes. This notice of proposed 

rulemaking addresses the Congressional 

mandate set forth in the Small Airplane 

Revitalization Act of 2013. 

DATES: Send comments on or before 

May 13, 2016. 

ADDRESSES: Send comments identified 

by docket number FAA–2015–1621 

using any of the following methods: 

• Federal eRulemaking Portal: Go to 

http://www.regulations.gov and follow 

the online instructions for sending your 

comments electronically. 

• Mail: Send comments to Docket 

Operations, M–30; U.S. Department of 

Transportation (DOT), 1200 New Jersey 

Avenue SE., Room W12–140, West 

Building Ground Floor, Washington, DC 

20590–0001. 

• Hand Delivery or Courier: Take 

comments to Docket Operations in 

Room W12–140 of the West Building 

Ground Floor at 1200 New Jersey 

Avenue SE., Washington, DC, between 9 

a.m. and 5 p.m., Monday through 

Friday, except Federal holidays. 

• Fax: Fax comments to Docket 

Operations at 202–493–2251. 

Privacy: In accordance with 5 U.S.C. 

553(c), DOT solicits comments from the 

public to better inform its rulemaking 

process. DOT posts these comments, 

without edit, including any personal 

information the commenter provides, to 

www.regulations.gov, as described in 

the system of records notice (DOT/ALL– 

14 FDMS), which can be reviewed at 

http://www.dot.gov/privacy. 

Docket: Background documents or 

comments received may be read at 

http://www.regulations.gov at any time. 

Follow the online instructions for 

accessing the docket or go to the Docket 

Operations in Room W12–140 of the 

West Building Ground Floor at 1200 

New Jersey Avenue SE., Washington, 

DC, between 9 a.m. and 5 p.m., Monday 

through Friday, except Federal holidays. 

FOR FURTHER INFORMATION CONTACT: For 

technical questions concerning this 

action, contact Lowell Foster, 

Regulations and Policy, ACE–111, 

Federal Aviation Administration, 901 

Locust St., Kansas City, MO 64106; 

telephone (816) 329–4125; email 

lowell.foster@faa.gov. 

SUPPLEMENTARY INFORMATION: Later in 

this preamble, under the Additional 

Information section, we discuss how 

you can comment on this proposal and 

how we will handle your comments. 

This discussion includes related 

information about the docket, privacy, 

and the handling of proprietary or 

confidential business information. We 

also discuss how you can get a copy of 

this proposal and related rulemaking 

documents. 

All sections of part 23 would contain 

proposed revisions, except the FAA 

would not make any substantive 

changes to the following sections: 

§§ 23.1457, Cockpit Voice Recorders, 

and 23.1459, Flight Data Recorders. The 

only proposed changes to § 23.1459 

would be for the purpose of aligning 

part 23 references. These sections are 

nevertheless included in this proposed 

revision for context. 

Table of Contents 

I. Executive Summary 

A. Purpose and History of the Proposed 

Performance-Based Standards 

B. Summary of Major Provisions 

1. Performance Standards and Airplane 

Crashworthiness 

2. Loss of Control 

3. Icing Certification Standards 

C. Cost and Benefits 

II. Authority for This Rulemaking 

III. Background 

A. Part 23 History 

B. New Safety Requirements 

C. Benefits for the Existing Fleet 

D. Conforming Amendments and Other 

Minor Amendments 

E. Public Policy Implementation 

1. Regulatory Planning and Review 

2. Consensus Standards 

3. International Cooperation Efforts for 

Reorganizing Part 23 

F. Means of Compliance 

G. FAA Strategic Initiatives 

IV. Discussion of Proposal 

A. Reorganization of Airworthiness 

Standards Based on Risk and 

Performance 

B. Introduction of Simple Airplanes 

C. Establishing Performance-Based 

Standards and the Use of Means of 

Compliance 

D. Crashworthiness as an Illustration of the 

Benefits of Performance-Based 

Regulations 

E. Additional Requirements To Prevent 

Loss of Control 

F. Additional Requirements for Flight in 

Icing Conditions 

G. Production of Replacement and 

Modification Articles 

V. Key Terms and Concepts Used in This 

Document 

VI. Discussion of the Proposed Regulatory 

Amendments 

A. Part 23, Airworthiness Standards 

1. Subpart A—General 

2. Subpart B—Flight 

3. Subpart C—Structures 

4. Subpart D—Design and Construction 

5. Subpart E—Powerplant 

6. Subpart F—Equipment 

7. Subpart G—Flightcrew Interface and 

Other Information 

8. Appendices to Part 23 

B. Miscellaneous Amendments 

1. Production of Replacement and 

Modification Articles (§ 21.9) 

2. Designation of Applicable Regulations 

(§ 21.17) 

3. Issuance of Type Certificate: Primary 

Category Aircraft (§ 21.24) 

4. Flight Tests (§ 21.35) 

5. Instructions for Continued 

Airworthiness and Manufacturer’s 

Maintenance Manuals Having 

Airworthiness Limitations Sections 

(§ 21.50) 

6. Designation of Applicable Regulations 

(§ 21.101) 

7. Applicability (§ 35.1) 

8. Fatigue Limits and Evaluation (§ 35.37) 

9. Altimeter System Test and Inspection 

(Appendix E to Part 43) 

10. Powered Civil Aircraft With Standard 

Category U.S. Airworthiness Certificates: 

Instrument and Equipment Requirements 

(§ 91.205) 

11. Restricted Category Civil Aircraft: 

Operating Limitations (§ 91.313) 

12. Increased Maximum Certification 

Weights for Certain Airplanes Operated 

in Alaska (§ 91.323) 

13. Second In Command Requirements 

(§ 91.531) 

14. Additional Emergency Equipment 

(§ 121.310) 

15. Additional Airworthiness 

Requirements (§ 135.169) 

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1Special conditions give the manufacturer 

permission to build the aircraft, engine or propeller 

with additional capabilities not addressed in the 

regulations. A petition for exemption is a request 

to the FAA by an individual or entity asking for 

relief from the requirements of a regulation. 

Equivalent level of safety findings are made when 

literal compliance with a certification regulation 

cannot be shown and compensating factors exist 

which can be shown to provide an equivalent level 

of safety. 14 CFR parts 11 and 21 provides 

information on special conditions and exemptions. 

FAA Order 8110–112A provides standard 

procedures for issue paper and equivalent level of 

safety memoranda. 

2The FAA’s safety continuum philosophy is that 

one level of safety may not be appropriate for all 

aviation. The FAA accepts higher levels of risk, 

with correspondingly fewer requirements for the 

demonstration of compliance, when aircraft are 

used for personal transportation. 

3See www.regulations.gov (Docket # FAA–2015– 

1621). 

4See www.regulations.gov (Docket # FAA–2015– 

1621). 

5http://www.gpo.gov/fdsys/pkg/CRPT112hrpt381/pdf/CRPT-112hrpt381.pdf. 

VII. Regulatory Notices and Analyses 

A. Regulatory Evaluation Summary 

B. Initial Regulatory Flexibility 

Determination 

C. International Trade Impact Assessment 

D. Unfunded Mandates Assessment 

E. Paperwork Reduction Act 

F. International Compatibility and 

Cooperation 

G. Environmental Analysis 

H. Regulations Affecting Intrastate 

Aviation in Alaska 

VIII. Executive Order Determination 

A. Executive Order 13132, Federalism 

B. Executive Order 13211, Regulations 

That Significantly Affect Energy Supply, 

Distribution, or Use 

IX. Additional Information 

A. Comments Invited 

B. Availability of Rulemaking Documents 

Appendix 1 to the Preamble—Current to 

Proposed Regulations Cross-Reference 

Table 

Appendix 2 to the Preamble—Abbreviations 

and Acronyms Frequently Used In This 

Document 

I. Executive Summary 

A. Purpose and History of the Proposed 

Performance-Based Standards 

Part 23 of Title 14 of the Code of 

Federal Regulations (14 CFR) prescribes 

airworthiness standards for issuance 

and amendment of type certificates for 

airplanes with a passenger-seating 

configuration of 19 or less and a 

maximum certificated takeoff weight of 

19,000 pounds or less. Airplanes 

certificated under part 23 are typically 

used for recreation, training, personal 

travel, and limited commercial 

applications. 

The current part 23 airworthiness 

standards are largely prescriptive, 

meaning that they describe detailed 

design requirements, and are based on 

airplane designs from the 1950’s and 

1960’s. As a result of this prescriptive 

framework, the FAA often requires a 

design approval applicant seeking to 

incorporate new or innovative 

technology to provide additional 

documentation that typically results in 

the FAA’s issuance of special 

conditions, exemptions, or equivalent 

level of safety (ELOS) findings.1 The 

FAA recognizes that these additional 

procedures and requirements are costly 

to the FAA and industry, act as barriers 

to certification, and discourage 

innovation. Therefore, to encourage the 

installation of new safety-enhancing 

technology and streamline the 

certification process, the FAA proposes 

replacing the prescriptive requirements 

found in the current part 23 with 

performance-based standards. 

The FAA believes this proposed 

rulemaking would maintain the level of 

safety associated with current part 23, 

while providing greater flexibility to 

applicants seeking certification of their 

airplane designs. By doing so, this 

proposed rulemaking would hasten the 

adoption of safety enhancing technology 

in type-certificated products while 

reducing regulatory time and cost 

burdens for the aviation industry and 

FAA. This proposed rulemaking would 

also reflect the FAA’s safety continuum 

philosophy,2 which balances the need 

for an acceptable level of safety with the 

societal burden of achieving that level 

safety, across the broad range of airplane 

types certificated under part 23. 

This proposed rulemaking is the 

result of an effort the FAA began in 

2008 to re-evaluate the way it sets 

standards for different types of 

airplanes. Through this effort, a joint 

FAA and industry team produced the 

Part 23 Certification Process Study 3

(CPS), which reviewed the life cycle of 

part 23 airplanes to evaluate 

certification processes and develop 

recommendations. Two key 

recommendations were to (1) reorganize 

part 23 based on airplane performance 

and complexity rather than the existing 

weight and propulsion divisions, and 

(2) permit the use of consensus 

standards as a means to keep pace with 

rapidly increasing design complexity in 

the aviation industry. 

In 2010, with the CPS as a foundation, 

the FAA conducted a Part 23 Regulatory 

Review and held meetings with the 

public and industry to gain input on 

revising part 23. These meetings 

confirmed strong public and industry 

support for the CPS recommendations to 

revise part 23. 

In 2011, the FAA formed the Part 23 

Reorganization ARC to consider further 

the CPS recommendation to reorganize 

part 23 based on airplane performance 

and complexity and to investigate the 

use of consensus standards. The ARC 

recommendations,4 published in 2013, 

echo the CPS recommendations. 

On January 7, 2013, Congress passed 

the Federal Aviation Modernization and 

Reform Act of 2012 5 (Public Law 112– 

95; 49 U.S.C. 40101 note) (FAMRA), 

which requires the Administrator, in 

consultation with the aviation industry, 

to assess the aircraft certification and 

approval process. Based on the ARC 

recommendations and in response to 

FAMRA, the FAA began work on this 

proposed rulemaking on September 24, 

2013. Subsequently, on November 27, 

2013, Congress passed the Small 

Airplane Revitalization Act of 2013 

(Public Law 113–53, 49 U.S.C. 44704 

note) (SARA), which requires the FAA 

to issue a final rule revising the 

certification requirements for small 

airplanes by— 

• Creating a regulatory regime that 

will improve safety and decrease 

certification costs; 

• Setting safety objectives that will 

spur innovation and technology 

adoption; 

• Replacing prescriptive rules with 

performance-based regulations; and 

• Using consensus standards to 

clarify how safety objectives may be met 

by specific designs and technologies. 

The FAA believes that the 

performance-based-standards 

component of this proposal complies 

with the FAMRA and the SARA because 

it would improve safety, reduce 

regulatory compliance costs, and spur 

innovation and the adoption of new 

technology. This proposal would 

replace the weight-and propulsionbased prescriptive airworthiness 

standards in part 23 with performanceand risk-based airworthiness standards 

for airplanes with a maximum seating 

capacity of 19 passengers or less and a 

maximum takeoff weight of 19,000 

pounds or less. The proposed standards 

would maintain the level of safety 

associated with the current part 23, 

while also facilitating the adoption of 

new and innovative technology in 

general aviation (GA) airplanes. 

B. Summary of Major Provisions 

This proposal to revise part 23 has 

two principal components: Establishing 

a performance-based regulatory regime 

and adding new certification standards 

for loss of control (LOC) and icing. 

Where the FAA proposes to establish 

new certification requirements, these 

requirements would be adopted within 

the same performance-based framework 

proposed for part 23 as a whole. 

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6SLD conditions include freezing drizzle and 

freezing rain, which contain drops larger than those 

specified in appendix C to part 25, and can accrete 

aft of wing leading edge ice protection systems. 

1. Performance Standards and Airplane 

Crashworthiness 

Airplane crashworthiness and 

occupant safety is an example of how 

moving towards performance-based 

standards and providing greater 

flexibility to industry would increase 

aviation safety. Although the FAA has 

over the years incrementally amended 

part 23 to enhance occupant safety, 

these amendments have focused on 

individual system components, rather 

than the safety of the system as a whole. 

By building greater flexibility into FAA 

regulations governing crash testing, this 

proposal would allow the aviation 

industry to develop and implement 

novel solutions. 

2. Loss of Control 

One proposed revision to part 23 

would improve general aviation safety 

by creating additional certification 

standards to reduce LOC accidents. 

Inadvertent stalls resulting in airplane 

LOC are the most common cause of 

small airplane fatal accidents. These 

LOC accidents frequently occur in the 

traffic pattern or at low altitudes, where 

the airplane is too low for a pilot to 

recover control before impacting the 

ground. The proposed revisions would 

require applicants to use new design 

approaches and technologies to improve 

airplane stall characteristics and pilot 

situational awareness to prevent such 

accidents. 

3. Icing Certification Standards 

Another proposed revision to part 23 

would improve GA safety by addressing 

severe icing conditions. In the 1990s, 

the FAA became aware of the need to 

expand the icing conditions considered 

during the certification of airplanes and 

turbine aircraft engines. In particular, 

the FAA determined that revised icing 

certification standards should include 

Supercooled Large Drops (SLD),6 mixed 

phase, and ice crystals. 

This proposed rule would require 

manufacturers that choose to certify an 

airplane for flight in SLD to demonstrate 

safe operations in SLD conditions. For 

those manufacturers who choose instead 

to certify an airplane with a prohibition 

against flight in SLD conditions, this 

proposed rule would require a means 

for detecting SLD conditions and 

showing the airplane can safely exit 

such conditions. Industry has indicated 

that these requirements would not 

impose significant additional cost 

burden on industry because many 

manufacturers already have equipped 

recent airplanes with technology to 

meet the standards for detecting and 

exiting SLD conditions in accordance 

with current FAA guidance. 

C. Cost and Benefits 

The goal of this proposal is to create 

a cost-effective approach to certification 

that facilitates the adoption of new 

safety enhancing technologies and 

allows for alternative means of 

compliance. The FAA has analyzed the 

benefits and costs associated with this 

NPRM. If the proposed rule saves only 

one human life, for example, by 

improving stall characteristics and stall 

warnings, that alone would result in 

benefits outweighing the costs. The 

following table shows these results. 

ESTIMATED BENEFITS AND COSTS FROM 2017 TO 2036 

[2014 $ millions] 

Costs Safety benefits + cost 

savings = total benefits 

Total .......................................................................................................................................................... $3.9 $19.6 + $12.6 = $32.2. 

Present value ............................................................................................................................................ 3.9 $6.2 + $5.8 = $12.0. 

Accordingly, the FAA has determined 

that the proposed rule would be cost 

beneficial. 

II. Authority for This Rulemaking 

The FAA’s authority to issue rules on 

aviation safety is found in Title 49 of the 

United States Code. Subtitle I, Section 

106 describes the authority of the FAA 

Administrator. Subtitle VII, Aviation 

Programs, describes in more detail the 

scope of the agency’s authority. 

This rulemaking is promulgated 

under the authority described in 

Subtitle VII, Part A, Subpart III, Section 

44701. Under that section, the FAA is 

charged with promoting safe flight of 

civil airplanes in air commerce by 

prescribing minimum standards 

required in the interest of safety for the 

design and performance of airplanes. 

This regulation is within the scope of 

that authority because it prescribes new 

performance-based safety standards for 

the design of normal, utility, acrobatic, 

and commuter category airplanes. 

Additionally, this rulemaking 

addresses the Congressional mandate set 

forth in the Small Airplane 

Revitalization Act of 2013 (Public Law 

113–53; 49 U.S.C. 44704 note) (SARA). 

Section 3 of SARA requires the 

Administrator to issue a final rule to 

advance the safety and continued 

development of small airplanes by 

reorganizing the certification 

requirements for such airplanes under 

part 23 to streamline the approval of 

safety advancements. SARA directs that 

the rule address specific 

recommendations of the 2013 Part 23 

Reorganization Aviation Rulemaking 

Committee (ARC). 

III. Background 

The range of airplanes certificated 

under part 23 is diverse in terms of 

performance capability, number of 

passengers, design complexity, 

technology, and intended use. 

Currently, each part 23 airplane’s 

certification requirements are 

determined by reference to a 

combination of factors, including 

weight, number of passengers, and 

propulsion type. The resulting divisions 

(i.e., normal, utility, acrobatic, and 

commuter categories) historically were 

appropriate because there was a clear 

relationship between the propulsion 

and weight of the airplane and its 

associated performance and complexity. 

Technological developments have 

altered the dynamics of that 

relationship. For example, highperformance and complex airplanes 

now exist within the weight range that 

historically was occupied by only light 

and simple airplanes. The introduction 

of high-performance, lightweight 

airplanes required subsequent 

amendments of part 23 to include more 

stringent and demanding standards— 

often based on the part 25 requirements 

for larger transport category airplanes— 

to ensure an adequate level of safety for 

airplanes under part 23. The unintended 

result is that some of the more stringent 

and demanding standards for highperformance airplanes now apply to the 

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7Section 312(c) 8Section 312 (b)(6) 

certification of simple and lowperformance airplanes. 

A. Part 23 History 

Part 23 originated from performancebased requirements developed by the 

Bureau of Air Commerce and the Civil 

Aeronautics Administration in the 

1930s. These regulations were contained 

in specific Civil Air Regulations (CAR) 

for the certification of aircraft (i.e., CAR 

3, 4, and 4a). These requirements, along 

with various bulletins and related 

documents, were subsequently revised 

and first published as 14 CFR part 23 in 

1964 (29 FR 17955, December 18, 1964). 

Over the past five decades and after 

numerous amendments, part 23 has 

evolved into a body of highly complex 

and prescriptive requirements 

attempting to codify specific design 

requirements, address specific problems 

encountered during prior certification 

projects, and respond to specific 

recommendations from the National 

Transportation Safety Board (NTSB). 

Although the intent of the 

prescriptive language contained in 

current part 23 was to increase the level 

of safety, prevent confusion, and clarify 

ambiguities, the current regulations 

have also restrained manufacturers’ 

ability to employ new designs and 

testing methodologies. The FAA 

believes moving towards performancebased standards should significantly 

reduce or eliminate barriers to 

innovation and facilitate the 

introduction of new safety-enhancing 

technologies. 

In 2008, the FAA conducted a review 

of part 23 by initiating the Part 23 CPS. 

Collaborating with industry, the team’s 

challenge was to determine the future of 

part 23, given today’s current products 

and anticipated future products. The 

team identified opportunities for 

improvements by examining the entire 

life cycle of a part 23 airplane. The CPS 

recommended reorganizing part 23 

using criteria focused on performance 

and design complexity. The CPS also 

recommended that the FAA implement 

general airworthiness requirements, 

with the means of compliance defined 

in industry consensus standards 

standards. In 2010, following the 

publication of the Part 23 CPS, the FAA 

held a series of public meetings to seek 

feedback concerning the findings and 

recommendations. Overall, the feedback 

was supportive of and in some cases 

augmented the CPS recommendations. 

One notable difference between the 

CPS findings and the public feedback 

was the public’s request that the FAA 

revise part 23 certification requirements 

for simple, entry-level airplanes. Over 

the past two decades, part 23 standards 

have become more complex as industry 

has generally shifted towards 

correspondingly complex, highperformance airplanes. This transition 

has placed an increased burden on 

applicants seeking to certificate smaller, 

simpler airplanes. Public comments 

requested that the FAA focus on 

reducing the costs and time burden 

associated with certificating small 

airplanes by restructuring the 

requirements based on perceived risk. 

The safety risk for most simple airplane 

designs is typically low. 

On August 15, 2011, the 

Administrator chartered the Part 23 

Reorganization ARC to consider the 

following CPS recommendations— 

• Recommendation 1.1.1—Reorganize 

part 23 based on airplane performance 

and complexity, rather than the existing 

weight and propulsion divisions; and 

• Recommendation 1.1.2— 

Certification requirements for part 23 

airplanes should be written on a broad, 

general, and progressive level, 

segmented into tiers based on 

complexity and performance. 

The ARC’s recommendations took 

into account the FAMRA, which 

requires the Administrator, in 

consultation with the aviation industry, 

to assess the aircraft certification and 

approval process. The purpose of the 

ARC’s assessment was to develop 

recommendations for streamlining and 

reengineering the certification process 

to improve efficiency, reduce costs, and 

ensure that the Administrator can 

conduct certifications and approvals in 

a manner that supports and enables the 

development of new products and 

technologies and the global 

competitiveness of the United States 

aviation industry.7 FAMRA also directs 

the Administrator to consider the 

recommendations from the Part 23 

Certification Process Study.8

ARC membership represented a broad 

range of of stakeholder perspectives, 

including U.S. and international 

manufacturers, trade associations, and 

foreign civil aviation authorities. The 

ARC was supported by FAA subject 

matter experts from all affected lines of 

business, from design and production 

certification to continued airworthiness 

and alterations. The following table 

identifies ARC participants: 

U.S. Manufacturers 

Avidyne ............................................................... Bendix-King ...................................................... Cessna. 

Cirrus .................................................................. Continental Motors ........................................... Cub Crafters. 

GAMI .................................................................. Garmin ............................................................. Hawker Beechcraft. 

Honda ................................................................. Honeywell ......................................................... Kestrel. 

Lockheed Martin ................................................. Rockwell-Collins ............................................... Quest. 

Sensenich Propellers ......................................... Tamarack Aero ................................................ TruTrak. 

U.S. Organizations 

Aircraft Electronics Association (AEA) ............... Aircraft Owners and Pilots Association 

(AOPA).

ASTM. 

Experimental Aircraft Association (EAA) ............ General Aviation Manufacturers Association 

(GAMA).

National Air Traffic Controllers Association 

(NATCA). 

RTCA .................................................................. SAE.

International Manufacturers 

Dassault Falcon .................................................. Diamond ........................................................... Flight Design. 

Rotax .................................................................. Socata.

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International Civil Aviation Authorities 

European Aviation Safety Agency (EASA) ........ Transport Canada Civil Aviation (TCCA) ......... National Civil Aviation Agency of Brazil 

(ANAC). 

Civil Aviation Administration of China (CAAC) ... Civil Aviation Authority of New Zealand.

Each member or participant on the 

committee represented an identified 

segment of the aviation community, 

with the authority to speak for that 

segment. The ARC also invited subject 

matter experts to support specialized 

working groups and subgroups, as 

necessary. These working groups 

developed recommendations and 

briefed the ARC as a whole. The ARC 

then collectively discussed and voted to 

accept or reject the recommendations. 

All of the recommendations included in 

the ARC’s report had overwhelming 

majority agreement. 

The ARC noted the prevailing view 

within industry was that the only way 

to reduce the program risk, or business 

risk, associated with the certification of 

new airplane designs was to avoid novel 

design approaches and testing 

methodologies. The certification of new 

and innovative products today 

frequently requires the FAA’s use of 

ELOS findings, special conditions, and 

exemptions. These take time, resulting 

in uncertainty and high project costs. 

The ARC emphasized that although 

industry needs from the outset to 

develop new airplanes designed to use 

new technology, current certification 

costs inhibit the introduction of new 

technology. The ARC identified 

prescriptive certification requirements 

as a major barrier to installing 

safety-enhancing modifications in the 

existing fleet and to producing newer, 

safer airplanes. 

The ARC also examined the 

harmonization of certification 

requirements among the FAA and 

foreign civil aviation authorities (CAAs), 

and the potential for such 

harmonization to improve safety while 

reducing costs. Adopting performancebased safety regulations that facilitate 

international harmonization, coupled 

with internationally accepted means of 

compliance, could result in both 

significant cost savings and the enabling 

of safety-enhancing equipment 

installations. The ARC recommended 

that internationally accepted means of 

compliance should be reviewed and 

voluntarily accepted by the appropriate 

aviation authorities, in accordance with 

a process established by those 

authorities. Although each CAA would 

be capable of rejecting all or part of any 

particular means of compliance, the 

intent would be to have full civil 

authority participation in the creation of 

the means of compliance to ease 

acceptance of the means of compliance. 

B. New Safety Requirements 

The performance-based standards 

proposed in this NPRM are designed to 

maintain the level of safety provided by 

current part 23 requirements. The 

current part 23 weight and propulsion 

divisions were based on assumptions 

that do not reflect the diversity of 

performance capabilities, design 

complexity, technology, intended use, 

and seating capacity of today’s new 

airplane designs, or the future airplane 

designs that will become possible as 

technology continues to evolve. The 

FAA would therefore replace the 

current divisions with certification 

levels 1 thru 4, low performance, high 

performance, and simple. Furthermore, 

this would replace the current divisions 

within the individual sections with 

technical and operational capabilities 

focused on the technical drivers (e.g., 

stall speed, Visual Flight Rules (VFR) 

and Instrument Flight Rules (IFR) 

operations, pressurization). These types 

of technical and operational criteria 

would apply a more appropriate set of 

standards to each airplane, and continue 

to accommodate the wide range of 

airplane designs within part 23. 

To begin, the FAA proposes to 

eliminate commuter, utility, and 

acrobatic airplane categories from part 

23, retaining only a normal category for 

all new part 23 type certificated airplane 

design approvals. The differences 

between normal, utility, and acrobatic 

categories are currently very limited and 

primarily affect airframe structure 

requirements. Proposed part 23 would 

continue to allow a normal category 

airplane to be approved for aerobatics, 

provided the airplane is certificated for 

the safety factors and defined limits of 

aerobatic operations. 

In addition, the FAA proposes that 

airplanes approved for spins be 

certificated to aerobatic standards. 

Under the current § 23.3(b), the utility 

category provides airplanes additional 

margin for the more stringent inertial 

structural loads resulting from intended 

spins and other maneuvers. An airplane 

designed with traditional handling 

qualities and designed to allow spin 

training is more susceptible to 

inadvertent departure from controlled 

flight. The FAA therefore believes that 

maintaining the current utility category 

for spin and limited aerobatic maneuver 

capable airplanes would negate the 

largest, single safety gain expected from 

this rulemaking action—the significant 

reduction in inadvertent stall-related 

departures from controlled flight. 

Under this proposal, airplanes already 

certificated in the commuter, utility, 

and acrobatic categories would continue 

to fall within those categories. Each new 

airplane design, however, would be 

subject to varying levels of analysis, 

based on the potential risk and 

performance of the airplane’s design. A 

more rigorous standard, such as 

currently applied to commuter category 

airplanes, would apply to higher risk 

and higher performance airplanes. 

The proposed requirements would 

also include new enhanced standards 

for resistance to departure from 

controlled flight. Recognizing that the 

largest number of fatal accidents for part 

23 airplanes results from LOC in flight, 

the FAA proposes to update 

certification standards to address these 

risks. LOC happens when an airplane 

enters a flight regime outside its normal 

flight envelope or performance 

capabilities and develops into a stall or 

spin, an event that can surprise the 

pilot. A pilot’s lack of awareness of the 

state of the airplane in flight and the 

airplane’s low-speed handling 

characteristics are the main causal 

factors of LOC accidents. Furthermore, 

stall and departure accidents are 

generally fatal because an airplane is 

often too low to the ground for the pilot 

to recover. Improving safety that 

reduces stall and LOC accidents would 

save lives. The FAA is therefore 

proposing new rules for stall 

characteristics and stall warnings that 

would result in airplane designs more 

resistant to inadvertently departing 

controlled flight. 

Another type of low-speed LOC 

accident that occurs in significant 

numbers involves minimum control 

speed (VMC) in light twin-engine 

airplanes. Virtually all twin-engine 

airplanes have a VMC that allows 

directional control to be maintained 

after one engine fails. This speed is 

usually above the stall speed of the 

airplane. However, light twin-engine 

airplanes typically have limited climb 

capability on one engine. In the 

accidents reviewed by the ARC and 

FAA, often in these situations, pilots 

attempted to maintain a climb or 

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9See www.regulations.gov (Docket #FAA–2015– 

1621), Air France A330–203, Flight AF 447 Final 

Accident Report 

10See www.regulations.gov (Docket #FAA–2015– 

1621) 

maintain altitude, which slowed the 

airplane down, rather than looking for 

the best landing site immediately, 

maintaining control the whole way. If 

the airplane’s speed drops below VMC, 

the pilot can lose control. In tying the 

minimum control speed to the stall 

speed of the airplane, pilots, rather than 

attempting to maintain climb and lose 

directional control, would instead react 

appropriately with stall training 

techniques, resulting in a controlled 

descent rather than a loss of directional 

control. This requirement will be on 

new airplanes and should add little or 

no cost because it can be designed in 

from the start. 

The FAA also has identified a need 

for improved certification standards 

related to operations in severe icing 

conditions. More specifically, in the 

1990’s, the FAA became aware of the 

need to expand the icing conditions 

considered during the certification of 

airplanes and turbine aircraft engines, to 

increase flight safety during some severe 

icing conditions. The 1994 accident in 

Roselawn, Indiana, involving an Avions 

de Transport Regional ATR 72 series 

airplane in SLD conditions, brought to 

public and governmental attention 

safety concerns about the adequacy of 

the existing icing certification 

standards. 

As a result of the 1994 accident, and 

consistent with related NTSB 

recommendations, in 1997 the 

Administrator tasked the Aviation 

Rulemaking Advisory Committee 

(ARAC) (62 FR 64621, December 8, 

1997) with defining SLD, mixed phase, 

and ice crystal icing environments, and 

designing corresponding safety 

requirements for those conditions. In 

June 2000, the ARAC’s task was revised 

to address only transport category 

airplanes. More recent events, such as 

an Air France Airbus model A330–203 

AF447 9 accident, in 2009, highlighted 

the negative effects of ice crystals on 

airspeed indication systems and turbojet 

engines. 

The FAA ultimately published 

amendments 25–140 (79 FR 65507, 

November 4, 2014) and 33–34 (79 FR 

65507, November 4, 2014), Airplane and 

Engine Certification Requirements in 

Supercooled Large Drop, Mixed Phase, 

and Ice Crystal Icing Conditions that 

expanded parts 25 and 33 icing 

requirements, but did not amend part 23 

requirements. On February 19, 2010, the 

Administrator chartered a Part 23 Icing 

ARC to review and recommend SLD, 

mixed phase, and ice crystal icing 

conditions regulations and guidance for 

part 23. In February 2012, the Part 23 

Icing ARC formally identified a need to 

improve the part 23 regulations to 

ensure safe operation of airplanes and 

engines in SLD and ice crystal 

conditions.10 In particular, the Part 23 

Icing ARC recommended adopting most 

of the part 25 icing rules, including the 

requirement to show either that an 

airplane can safely fly in SLD 

conditions, or that it can detect and 

safely exit SLD. The proposals in this 

NPRM incorporate the 

recommendations of the Part 23 Icing 

ARC. 

C. Benefits for the Existing Fleet 

The proposed revisions would benefit 

owners and modifiers of existing part 23 

airplanes, as well as airplane designers 

and manufacturers. Both currently and 

under this proposal, airplanes may be 

modified by: (1) An alteration to an 

individual airplane; (2) a supplemental 

type certificate (STC) for multiple 

airplanes, or (3) an amendment to an 

original type design via an amended 

type certificate (TC). This proposal 

would streamline each of these methods 

for modifying airplanes. 

The proposed change to § 21.9 would 

facilitate FAA approval of low-risk 

equipment produced for installation in 

type-certificated airplanes, thereby 

streamlining the process for owners to 

upgrade equipment on their individual 

airplanes. An example of how this 

change would facilitate safety 

improvements is the installation of 

inexpensive weather display systems in 

the cockpits of small airplanes. These 

systems allow a pilot to view current 

weather conditions along the planned 

flight route and at the destination 

airport, avoiding unexpected or 

deteriorating weather conditions. Since 

these systems are not required and 

because they represent low safety risk 

from failure, the FAA believes 

streamlining its approval process to 

produce them for use in existing 

airplanes could lower costs and increase 

availability of these systems. 

The proposed changes in the rules 

would also streamline the process for 

design approval holders applying for a 

type design change, or for a third party 

modifier applying for an STC, to 

incorporate new and improved 

equipment in a model or several models 

of airplanes. Since the revised part 23 

standards would be much less 

prescriptive, the certification process for 

modifications would be simplified. 

Certification of an amended TC or STC 

under the proposed part 23 standards 

would require fewer special conditions 

or exemptions, lowering costs and 

causing fewer project delays. 

D. Conforming Amendments and Other 

Minor Amendments 

References to part 23 appear 

throughout the FAA’s current 

regulations. Accordingly, the FAA 

proposes to amend the following parts 

for consistency with the proposed 

revisions to part 23: Part 21, part 35, 

part 43, part 91, part 121, and part 135. 

The FAA also proposes to revise part 

21 to simplify the approval process for 

low-risk articles. Specifically, the FAA 

proposes amending § 21.9 to allow FAAapproved production of replacement 

and modification articles using methods 

not listed in § 21.9(a). This proposed 

change is intended to reduce constraints 

on the use of non-required, low risk 

articles, such as carbon monoxide 

detectors and weather display systems. 

E. Public Policy Implementation 

The intent of this NPRM is to reduce 

regulatory barriers by establishing a 

system based on safety-focused 

performance requirements and FAA 

acceptance—as a means of 

compliance—of consensus standards. 

FAA-accepted consensus standards 

would add clarity to the certification 

process and streamline FAA 

involvement in the development of 

means of compliance. Additionally, 

adopting performance standards would 

significantly reduce the complexity of 

part 23. Furthermore, the introduction 

of airplane certification levels based on 

risk (i.e., number of passengers) and 

performance (i.e., speed) would advance 

the FAA’s effort to introduce risk-based 

decision-making and better align with 

the FAA’s safety continuum philosophy. 

Together, the FAA believes these 

changes would allow the FAA to 

provide appropriate oversight based on 

the safety continuum and would restore 

a simple and cost effective certification 

process based on proven engineering 

practices. 

1. Regulatory Planning and Review 

In accordance with applicable 

executive orders, the FAA has 

determined that the proposed revisions 

to part 23 are the most cost-beneficial 

way of achieving the agency’s regulatory 

objectives. This is because the proposal 

would relieve industry of a significant 

regulatory burden while maintaining or 

improving the level of safety under the 

regulations. In particular, Executive 

Order 12866, Regulatory Planning and 

Review (58 FR 51735, October 4, 1993), 

and Executive Order 13563, Improving 

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12http://www.gpo.gov/fdsys/pkg/PLAW104publ113/pdf/PLAW-104publ113.pdf. 

13https://www.whitehouse.gov/omb/circulars_

a119/. 

14CAAs included participants from Brazil, 

Canada, China, Europe, and New Zealand. 

Regulation and Regulatory Review (76 

FR 3821, January 21, 2011), direct each 

Federal agency to propose or adopt a 

regulation only upon a reasoned 

determination that the benefits of the 

intended regulation justify its costs. 

This proposal is not an economically 

‘‘significant regulatory action’’ as 

defined in section 3(f) of Executive 

Order 12866 11 and it satisfies Executive 

Order 13563 by protecting public 

health, welfare, safety, while promoting 

economic growth, innovation, 

competitiveness, and job creation. 

Under the above-referenced executive 

orders, when an agency determines that 

a regulation is the best available method 

of achieving its regulatory objective, the 

agency must design the regulation or 

regulations in the most cost-effective 

manner. In doing so, each agency must 

consider incentives for innovation, 

consistency, predictability, enforcement 

and compliance costs (to the 

government, regulated entities, and the 

public), flexibility, distributive impacts, 

and equity. Each agency must identify 

and assess alternative forms of 

regulation and shall specify, to the 

extent feasible, performance objectives, 

rather than specifying the behavior or 

manner of compliance that regulated 

entities must adopt. This proposal meets 

these requirements because it would 

implement performance objectives 

rather than a prescriptive methodology, 

thereby reducing time and cost burdens 

on industry and increasing 

opportunities for innovation. 

Executive Order 13610, Identifying 

and Reducing Regulatory Burdens (77 

FR 28469, May 10, 2012) reiterates the 

direction from Executive Order 13563 in 

stating that our regulatory system must 

measure, and seek to improve, the 

actual results of regulatory 

requirements. To promote this goal, 

agencies are to engage in periodic 

review of existing regulations, and are 

required to develop retrospective review 

plans to examine existing regulations in 

order to determine whether any such 

regulations should be modified, 

streamlined, expanded, or repealed. The 

purpose of this requirement is to make 

the agency’s regulatory program more 

effective or less burdensome in 

achieving the regulatory objectives. In 

response to Executive Orders13563 and 

13610, agencies have developed and 

made available for public comment 

retrospective review plans. Both the Part 

23 Reorganization ARC and this Part 23 

Rulemaking Project are on the 

Department of Transportation’s 

retrospective review plans. 

2. Consensus Standards 

Section 3(c) of SARA requires the 

Administrator, when developing 

regulations, to comply with the 

requirements of the National 

Technology Transfer and Advancement 

Act of 1995 12 (Pub. L. 104–113; 15 

U.S.C. 272 note) (NTTAA) and to use 

consensus standards to the extent 

practicable while maintaining 

traditional methods for meeting part 23. 

Section 12(d) of the NTTAA directs 

Federal agencies to use, either by 

reference or by inclusion, voluntary 

consensus standards in lieu of 

government-mandated standards, except 

where inconsistent with law or 

otherwise impractical. The Office of 

Management and Budget (OMB) 

Circular A–119,13 Federal Participation 

in the Development and Use of 

Voluntary Consensus Standards and 

Conformity Assessment Activities, 

provides guidance to Executive agencies 

in implementing the requirements of the 

NTTAA. 

Accordingly, the FAA proposes to 

accept consensus standards as a means 

of compliance with the proposed part 23 

performance-based regulations. The use 

of consensus standards would be one 

means of compliance with the 

performance-based standards of the 

proposed part 23. Compliance with the 

current prescriptive provisions within 

current part 23 would be yet another 

means of compliance available under 

this proposal. Applicants would still 

have the option to propose their own 

means of compliance as they do today. 

The process for reviewing new means of 

compliance would not change 

substantially from the process in place 

today. 

Although a consensus standard works 

in some cases, the Part 23 

Reorganization ARC expressed concerns 

that a consensus standard could be 

biased in favor of a few large 

manufacturers and thereby create an 

unfair competitive advantage. OMB 

Circular A–119 also cautions regulators 

to avoid such potential biases. The FAA 

notes that industry groups associated 

with the Part 23 Reorganization ARC 

identified ASTM International (ASTM) 

as the appropriate organization to 

initiate the development of consensus 

standards, and that ASTM permits any 

interested party to participate in the 

committees developing consensus 

standards. The FAA expects other 

consensus standards bodies to allow 

similar opportunities for interested 

parties to participate in their standardsdevelopment work. In addition to 

consensus standards and the current 

prescriptive design standards in part 23, 

any individual or organization may 

develop its own proposed means of 

compliance that may be submitted to 

the FAA for acceptance. 

3. International Cooperation Efforts for 

Reorganizing Part 23 

Executive Order 13609, Promoting 

International Regulatory Cooperation 

(77 FR 26413, May 4, 2012), promotes 

international regulatory cooperation to 

meet shared challenges and reduce, 

eliminate, or prevent unnecessary 

differences in regulatory requirements. 

Consistent with this Order, the FAA’s 

proposal would address unnecessary 

differences in regulatory requirements 

between the United States and its major 

trading partners. The U.S. GA industry 

has repeatedly informed the FAA of the 

high costs to address differences 

between the airworthiness requirements 

of the FAA and foreign CAAs. The FAA 

believes this proposal has the potential 

to achieve long-term harmonization at 

an unprecedented level, and should 

result in a significant savings for both 

U.S. manufacturers exporting products 

abroad and foreign manufacturers 

exporting products to the U.S. The FAA 

requests comments regarding the 

potential cost savings. 

The work of the Part 23 

Reorganization ARC forms the 

foundation of the proposed changes to 

part 23. From the onset, the ARC was a 

cooperative, international effort. 

Representatives from several foreign 

CAAs 14 and international members 

from almost every GA manufacturer of 

airplanes and avionics participated in 

the Part 23 Reorganization ARC. Several 

international light-sport aircraft 

manufacturers, who were interested in 

certificating their products using part 23 

airworthiness standards, also 

participated. In addition to 

recommending changes to part 23, the 

ARC developed proposals to help 

reduce certification costs through more 

international standardization of 

certification processes and reducing or 

eliminating redundant certification 

activities associated with foreign 

certification. 

After the ARC issued its report, the 

FAA, foreign CAAs, and industry 

continued to work together to refine the 

ARC rule language until the FAA began 

drafting the NPRM in December 2014. 

This included formal meetings in July 

and November of 2014. EASA, 

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Transport Canada, other foreign 

authorities, and industry offered 

significant contributions to these efforts. 

In addition, the CAAs from Europe, 

Canada, Brazil, China, and New Zealand 

are working to produce rules similar to 

those contained in this proposal. EASA, 

for example, published an Advance 

Notice of Proposed Amendment (A– 

NPA) 2015–06 on March 27, 2015, 

which sets forth EASA’s concept for its 

proposed reorganization of CS–23, and 

on which the FAA provided comments. 

Like the FAA’s current proposal, 

EASA’s A–NPA was also based on the 

proposed ARC language with the goal of 

harmonization. Both proposals would 

adopt performance-based standards that 

facilitate the use of consensus standards 

as a means of compliance. 

F. Means of Compliance 

This proposal would allow type 

certificate applicants to use FAAaccepted means of compliance to 

streamline the certification process. 

This proposal, however, is shaped by 

two concerns raised in the Part 23 

Reorganization ARC. First, the rule 

needs to clearly state that any applicant 

must use a means of compliance 

accepted by the Administrator when 

showing compliance with part 23. The 

FAA emphasizes that any means of 

compliance would require FAA review 

and acceptance by the Administrator. 

Second, although a means of 

compliance developed by a consensus 

standards body (i.e., ASTM, SAE, 

RTCA, etc.) may be available, any 

individual or organization would also 

be able to submit its own means of 

compliance documentation to the 

Administrator for consideration and 

potential acceptance. 

The FAA anticipates that both 

individuals and organizations would 

develop acceptable means of complying 

with the proposed performance 

standards. The industry groups 

associated with the ARC discussed the 

development of consensus-based 

standards and selected ASTM as the 

appropriate organization to initiate the 

effort. A standards organization such as 

ASTM could, for example, generate a 

series of consensus-based standards for 

review, acceptance, and public notice of 

acceptance by the FAA. The ASTM 

standards would be one way, but not the 

only way, to demonstrate compliance 

with part 23. 

Using means of compliance 

documents to satisfy compliance with 

the proposed performance-based rules 

would diminish the need for special 

conditions, ELOS findings, and 

exemptions to address new technology 

advancements. Once the Administrator 

accepted a means of compliance, it 

could be used in future certification 

applications unless formally rescinded. 

Incorporating the use of consensus 

standards as a means of compliance 

with performance-based regulations 

would provide the FAA with the agility 

to more rapidly accept new technology 

as it develops, leverage industry 

experience and expectations to develop 

of new means of compliance 

documents, and encourage the use of 

harmonized means of compliance 

among the FAA, industry, and foreign 

CAAs. Although an applicant would not 

be required to use previously accepted 

means of compliance documents, doing 

so would streamline the certification 

process by eliminating the need for the 

FAA to develop an issue paper to 

address the certification of new 

technology. Proposed Advisory Circular 

23.10, Accepted Means of Compliance, 

would describe a process for applicants 

to submit proposed means of 

compliance to the FAA for acceptance 

by the Administrator. 

The Part 23 Reorganization ARC was 

also concerned that specialists in the 

industry could argue for complex means 

of compliance when the FAA would 

accept a simpler or more cost effective 

approach. To address these concerns, 

the FAA would continue to allow 

applicants to propose their own means 

of compliance when the larger industry 

standard may be the appropriate level of 

safety for one but not all certification 

levels, consistent with the guidance in 

OMB Circular A–119, which reminds 

the regulator that the government is 

responsible to the public for setting the 

appropriate level of safety and avoiding 

any unfair competitive advantage. 

Additionally, the FAA proposes to 

continue to allow the use of the 

prescriptive means of compliance 

currently codified in part 23 as yet 

another alternative means of compliance 

with proposed part 23. This would not 

apply, however, to the proposed new 

requirements, such as §§ 23.200, 23.215, 

and 23.230. 

G. FAA Strategic Initiatives 

The FAA’s Strategic Initiatives 2014– 

2018 communicates FAA goals for 

addressing the challenges presented by 

the changing aviation industry and how 

the FAA intends to make the U.S. 

aviation system safer and smarter, and 

raise the bar on safety. Specifically, one 

strategic initiative is for the FAA to 

embrace and implement risk-based 

decision making approaches, which 

build on safety management principles 

to address emerging safety risks using 

consistent, data-informed approaches to 

make smarter, quicker system-level 

decisions. By establishing performancebased regulations, coupled with 

industry standards, this proposed 

rulemaking would provide a calibrated 

and globally competitive regulatory 

structure. This new approach would 

increase safety in general aviation by 

enabling and facilitating innovation and 

the implementation of safety enhancing 

designs in newly certificated products. 

This rulemaking effort also directly 

supports the FAA’s Global Leadership 

Initiative, by encouraging global 

harmonization and the consistent use of 

regulations, standards, and practices for 

general aviation airplanes. 

IV. Discussion of Proposal 

A. Reorganization of Airworthiness 

Standards Based on Risk and 

Performance 

The FAA proposes replacing the 

current weight and propulsion-based 

airplane certification divisions with 

airplane certification and performance 

levels based on the number of potential 

passengers and the performance of the 

airplane. The FAA believes this 

proposed regulatory change would 

better accommodate the wide range of 

airplanes certificated under part 23, 

thereby reducing certification risk, time, 

and costs. 

Historically, turbine-powered 

airplanes were assumed to fly at or 

above 18,000 feet (5,486 meters) and at 

high speeds, whereas piston engine 

airplanes were assumed to fly below 

18,000 feet (5,486 meters) and at lower 

speeds. Today, with advancements in 

aviation technology, these general 

design and performance assumptions 

may not be valid. Furthermore, the 

current regulations do not account for 

airplanes equipped with new 

technologies, such as electric 

propulsion systems, which may have 

features that are entirely different from 

piston and turbine engines. For these 

reasons, the FAA is proposing 

regulations based on airplane 

performance and potential risk rather 

than on assumptions about specific 

technologies. These proposed standards 

would be appropriate to each specific 

airplane design. 

Certification of airplanes under part 

23 would either be conducted using 

airplane certification levels based on 

maximum passenger seating 

configuration and airplane performance 

levels based on speed, or occur as socalled ‘‘simple airplanes’’ that are lowspeed airplanes with a stalling speed 

(VSO) ≤ 45 Knots Calibrated Airspeed 

(KCAS) approved only for VFR 

operations. The FAA proposes the 

following airplane certification levels: 

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• Level 1—for airplanes with a maximum 

seating configuration of 0 to 1 passengers, 

including simple airplanes. 

• Level 2—for airplanes with a maximum 

seating configuration of 2 to 6 passengers. 

• Level 3—for airplanes with a maximum 

seating configuration of 7 to 9 passengers. 

• Level 4—for airplanes with a maximum 

seating configuration of 10 to 19 passengers. 

B. Introduction of Simple Airplanes 

The regulations contained in part 23 

have gradually become more focused on 

high-performance, turbine-powered 

airplanes, and this emphasis has 

become a barrier to the efficient 

certification and introduction to market 

of new entry-level, simple airplanes. 

The Part 23 Reorganization ARC 

specifically noted that current part 23 

does not have appropriate standards for 

the certification of entry-level airplanes. 

The FAA proposes to define ‘‘simple 

airplanes’’ in § 23.5 to recognize the 

entry-level airplane. Simple airplanes 

would be limited to airplane designs 

that allow transport of no more than one 

passenger (in addition to the pilot), are 

limited to VFR operations, and have 

both a low top speed and a low stall 

speed. These airplanes are similar to 

EASA’s Certification Specification— 

Very Light Aeroplanes (CS–VLA), which 

are currently imported to the U.S. and 

certificated as special class airplanes in 

accordance with 14 CFR 21.17(b). The 

proposed change would allow these 

airplanes to be certified as normal 

category airplanes under part 23. 

The FAA believes that permitting 

certification of simple airplanes would 

allow more certified entry-level 

airplanes to enter the marketplace. The 

FAA expects simple airplanes to be a 

more basic sublevel within proposed 

certification level 1, but recognizes that 

because of similarities between simple 

and non-simple airplanes within 

certification level 1, creating this 

category may be unnecessary. For this 

reason, the FAA is specifically asking 

for comments concerning the utility of 

creating a separate, simple airplane 

sublevel. 

C. Establishing Performance-Based 

Standards and the Use of Means of 

Compliance 

The Part 23 Reorganization ARC was 

aware the Administrator has accepted as 

evidence of compliance various 

manufacturers’ internal design 

standards in the past, and the ARC 

recommended expressly stating that 

option in the proposal. Proposed 

§ 23.10, Accepted Means of Compliance, 

would allow individual persons or 

companies to submit their internal 

standards as means of compliance for 

consideration by the Administrator. 

Proposed § 23.10 would also require an 

applicant to show the FAA how it 

would demonstrate compliance with 

this part using a means of compliance, 

which may include consensus standards 

accepted by the Administrator. It would 

further require an applicant requesting 

acceptance of a means of compliance to 

provide the means of compliance to the 

FAA in a form and manner specified by 

the Administrator. In addition, 

proposed § 23.10 specifically recognizes 

the use of consensus standards as a 

means of compliance that could be 

acceptable to the Administrator. If this 

information is proprietary in nature, it 

would be afforded the same protections 

as are applied today in certification 

applications submitted under 14 CFR 

part 21. 

The phrase ‘‘means of compliance’’ 

may have different connotations 

depending on its context. Historically, 

the FAA has treated an applicant’s 

demonstration of compliance as a means 

of compliance. Alternatively, as 

indicated by sec. 3(b)(4) of the SARA, 

consensus standards may constitute a 

means of compliance that can address 

new and novel designs and 

technologies. In other words, as 

suggested by the SARA, an applicant 

would develop a design to satisfy a 

performance-based standard, and the 

design is the means of complying with 

the standard. 

Currently, an applicant for a type 

certificate must show the FAA how it 

satisfies the applicable airworthiness 

standards. The applicant submits the 

type design, test reports, and 

computations necessary to show 

compliance. The applicant approaches 

the FAA and enters into negotiations 

regarding what constitutes an adequate 

demonstration—testing or analysis. The 

FAA anticipates that, under the 

proposed framework, standards 

developed by consensus standards 

bodies would provide a pre-existing 

means by which any applicant may 

demonstrate compliance with the 

corresponding performance-based 

requirements. For example, the 

proposed fuel system requirements 

would be broad enough to certificate 

airplanes with electric propulsion 

systems in which batteries and fuel cells 

are used as fuel. Airplanes incorporating 

these systems cannot currently be 

certificated without applying for special 

conditions or exemptions. 

Elements of this proposal are already 

in place today. Industry standards 

bodies like RTCA, SAE, ASTM, and the 

European Organization for Civil 

Aviation Equipment (EUROCAE) have 

already developed detailed means of 

compliance documents that an 

applicant for a type certificate may use 

to demonstrate compliance with our 

regulatory requirements in 14 CFR parts 

23, 25, 27, and 29. For decades, the FAA 

has identified these means of 

compliance documents as an acceptable 

means of complying with our regulatory 

requirements. This proposal would 

build on and expand this aspect of our 

regulations by also transitioning part 23 

towards a regulatory framework based 

on performance standards. 

D. Crashworthiness as an Illustration of 

the Benefits of Performance-Based 

Regulations 

One area where the implications of a 

change from prescriptive to 

performance-based requirements are 

most evident is in the demonstration of 

crashworthiness. The current part 23 

crashworthiness and occupant safety 

requirements are based on seat and 

restraint technology used in the 1980’s. 

Currently, an applicant demonstrates 

crashworthiness by a sled test. Under 

the proposed standards, an applicant 

would not necessarily have to perform 

a sled test, but could instead employ a 

different method accounting for many 

other factors, several of which are 

described below. The FAA is imposing 

no new requirements, but would, under 

this proposal, provide greater flexibility 

to adopt new safety-testing 

methodologies and, ultimately, more 

advanced safety technologies. 

The FAA proposes to allow greater 

flexibility with respect to the testing and 

demonstration, similar to advancements 

made in the automotive industry over 

the past 30 years. The proposed 

regulations would facilitate evaluation 

of the entirety of a crashworthiness 

system—namely, the interaction of all 

crashworthiness features—rather than 

requiring an evaluation of discrete, 

individual parameters. A system’s 

ability to protect occupants can be better 

understood by evaluating it as a 

complete system, and using that greater 

understanding to develop and 

implement new technologies. Such an 

evaluation could include analyses of 

important survivability factors 

identified by the NTSB, including 

occupant restraints, survivable volume, 

energy-absorbing seats, and seat 

retention. These proposed 

crashworthiness standards would not 

necessarily prevent accidents, but 

should improve survivability. 

The NTSB produced a series of 

reports in the 1980s that evaluated over 

21,000 GA airplane crashes between 

1972 and 1981. The NTSB General 

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15See www.regulations.gov (Docket # FAA–2015– 

1621). 

16See www.regulations.gov (Docket # FAA–2015– 

1621). 

17See www.regulations.gov (Docket # FAA–2015– 

1621). 

Aviation Crashworthiness Project 15

evaluated airplane orientation, impact 

magnitudes, and survival rates and 

factors to provide information 

supporting changes in crashworthiness 

design standards for GA seating and 

restraint systems. The NTSB reports also 

established conditions approximating 

survivable accidents and identified 

factors that would have the largest 

impact on safety. Amendment 23–36 (53 

FR 30802, August 15, 1988) to part 23 

referenced these reports for dynamic 

seats but did not adopt a systemsevaluation approach. 

The NTSB reports identified several 

factors that, working together as a 

system, should result in a safer airplane. 

The assessment also indicated, however, 

that shoulder harnesses offer the most 

immediate individual improvement for 

safety. The FAA codified the shoulder 

harnesses requirement in amendments 

23–19 (42 FR 20601, June 16, 1977) and 

23–32 (50 FR 46872, November 13, 

1985) for newly manufactured airplanes. 

The FAA also issued policy statement 

ACE–00–23.561–01, Methods of 

Approval of Retrofit Shoulder Harness 

Installations in Small Airplanes,16 dated 

September 19, 2000, to streamline the 

process for retrofitting older airplanes. 

Current part 23 requires occupant 

restraints to maintain integrity, stay in 

place on the occupant throughout an 

event, properly distribute loads on the 

occupant, and restrain the occupant by 

mitigating interaction with other items 

in the cabin. Newer technologies that 

enhance or supplement the performance 

of these restraints, such as airbags, are 

now being considered for inclusion in 

designs. The use of airbags has greatly 

increased passenger safety in 

automobiles, by offering protection in 

much more severe impacts and in 

impacts from multiple directions. The 

proposed performance standards would 

enable the use of these technologies. 

Survivable volume is another critical 

factor in crashworthiness. Survivable 

volume is the ability of the airframe to 

protect the occupants from external 

intrusion, or the airplane cabin crushing 

during and after an accident. There were 

several observed accidents in the NTSB 

study where conventional airplane 

construction simply crushed an 

otherwise restrained occupant. 

Crashworthiness regulations have never 

included survivable volume as a factor, 

except in some instances in which an 

airplane turns over. Airplane designs 

should provide the space needed for the 

protection and restraint of the 

occupants. This is one of the first steps 

in the analysis of airplane 

crashworthiness. 

Data from the NTSB General Aviation 

Crashworthiness Project suggested that 

energy-absorbing seats that protect the 

occupant from vertical impact loads 

could enhance occupant survivability 

and prevent serious injury, thereby 

enhancing odds for exiting the airplane 

and preventing many debilitating longterm injuries. The FAA established 

dynamic seat testing requirements in 

amendment 23–36 for airplanes 

certificated under part 23. Energy 

absorbing seats have a smaller impact 

than some other safety factors because 

accident impacts with large vertical 

components tend to have lower odds of 

survival. Nevertheless, energy 

attenuation from vertical forces, both 

static and dynamic, has been important 

to crashworthiness regulations for the 

past 25 years. Seats may crush or 

collapse, but must remain attached to 

the body of the airplane. Coupling the 

seat performance to the rest of the 

airframe response is important to the 

enhancement and understanding of 

occupant survivability. The FAA 

believes allowing designers to consider 

airframe deformation would result in 

more accurate floor impulses, which 

relate to simulated crash impact, and 

may allow for evaluation for crash 

impulses in multiple directions. 

The NTSB also identified seat 

retention as another basic building 

block for airplane crashworthiness. The 

NTSB reports show more than a quarter 

of otherwise-survivable accidents 

included instances where the seats 

broke free at the attachment to the 

airplane, resulting in fatalities or serious 

injuries. Dynamic seat testing 

requirements address the ability of seat 

assemblies to remain attached to the 

floor, even when the floor shifts during 

impact. Pitching and yawing of the seat 

tracks during dynamic seat tests 

demonstrates the gimbaling and 

flexibility of the seat. 

The FAA believes that, under this 

proposal, all of these crashworthiness 

factors could be incorporated into future 

testing methodologies and thereby 

increase the survivability of accidents in 

part 23 certificated airplanes. This 

proposed part 23 amendment would 

authorize design approval applicants to 

use these technologies and testing 

methodologies to enhance occupant 

safety. 

E. Additional Requirements To Prevent 

LOC 

LOC continues to be the leading cause 

of fatal GA accidents. The FAA 

identified 74 accidents caused by stall 

or LOC between January 2008 and 

December 2013. These accidents, which 

are listed in Appendix IV of the Part 23 

Regulatory Evaluation,17 represent the 

type of accidents that could be 

prevented by the proposed new stall 

and LOC requirements. 

The FAA proposes to add 

requirements in §§ 23.200 and 23.215 to 

prevent LOC accidents. Inadvertent 

stalls resulting in airplane LOC cause a 

large number of small airplane fatal 

accidents. These LOC accidents in the 

traffic pattern or at low altitudes often 

result in fatalities because the airplane 

is too low to the ground for the pilot to 

recover control. The FAA therefore 

believes it can improve safety by 

requiring applicants to use new 

approaches to improve airplane stall 

characteristics to prevent such 

accidents. 

Another type of low-speed LOC 

accident that occurs in significant 

numbers involves VMC in light twinengine airplanes. Virtually all twinengine airplanes have a VMC that allows 

directional control to be maintained 

after one engine fails. This speed is 

typically above the stall speed of the 

airplane. However, light twin-engine 

airplanes also typically have limited 

climb capability on one engine. 

Moreover, after the failure of one 

engine, pilots often instinctively tend to 

try to maintain a climb or maintain 

altitude, which slows the airplane 

down. If the speed drops below VMC, the 

pilot can lose control of the airplane. 

Because pilots tend to be more aware of 

the airplane’s stall speed, the FAA 

proposes in § 23.200 that certification 

levels 1 and 2 multiengine airplanes 

would be required to have a VMC that 

does not exceed the stall speed of the 

airplane for each configuration. The 

FAA believes this proposed requirement 

would provide a higher level of safety 

than current § 23.149. The FAA requests 

comments on this proposal. 

The FAA also proposes new 

requirements in § 23.215 for airplane 

stall characteristics and stall warning 

that would result in airplane designs 

more resistant to inadvertently stalling 

and departing controlled flight. These 

proposed requirements would increase 

the level of safety over the current 

requirements. At the same time, the 

FAA proposes to eliminate the spin 

recovery requirement in the current 

rules for normal category airplanes. The 

FAA believes the spin recovery 

requirement is unnecessary for normal 

category airplanes because the vast 

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18See www.regulations.gov (Docket # FAA–2015– 

1621). 

majority of inadvertent stalls leading to 

spin entry occur below a safe altitude 

for spin recovery. However, airplanes 

certificated for aerobatics would still 

have to meet spin recovery 

requirements. 

The FAA also proposes to address 

pilot stall awareness by requiring 

warnings that are more effective and by 

allowing new approaches to improve 

pilot awareness of stall margins. These 

warnings could be as simple as angle of 

attack or energy awareness 

presentations, or sophisticated envelope 

protection systems that add a forward 

force to the pilot’s controls as the 

airplane speed and attitude approach 

stall. 

F. Additional Requirements for Flight in 

Icing Conditions 

The FAA proposes to implement the 

Part 23 Icing ARC’s recommendations in 

§§ 23.230, 23.940 and 23.1405, to allow 

an applicant the option of certifying an 

airplane to operate in SLD icing 

conditions. To do so, an applicant 

would be required to meet the same 

safety standards in SLD icing conditions 

as currently demonstrated for part 23 

airplanes in the icing conditions defined 

in appendix C to part 25. 

Currently, the FAA does not certify 

part 23 airplanes to operate in SLD icing 

conditions, also known as freezing 

drizzle and freezing rain. Instead, 

current part 23 icing regulations require 

airplane performance, flight 

characteristics, systems, and engine 

operation to be demonstrated in the 

icing conditions defined in appendix C 

to part 25, which does not contain SLD 

icing conditions. In 2012, prior to the 

Part 23 Reorganization ARC, the Part 23 

Icing ARC recommended revising part 

23 to include SLD icing requirements in 

subparts B, E, and F (Flight, Powerplant, 

and Equipment, respectively). 

If an applicant chooses not to certify 

an airplane in SLD icing conditions, 

proposed § 23.230 would require the 

applicant to demonstrate that SLD icing 

conditions could be detected and safely 

exited. A means of compliance for SLD 

detection and exit may be found in FAA 

Advisory Circular 23.1419–2D, 

Certification of Part 23 Airplanes for 

Flight in Icing Conditions.18 The service 

history of airplanes certificated under 

part 23 and certified to the latest icing 

standards has shown that AC 23.1419– 

2D provides an adequate level of safety 

for detecting and safely exiting SLD 

icing conditions. Industry has indicated 

that these requirements would not 

impose an additional burden because 

many manufacturers have already 

equipped recent airplanes to meet the 

standards for detecting and exiting SLD 

in accordance with current FAA 

guidance. Proposed § 23.230, along with 

proposed § 23.940, Powerplant ice 

protection, and § 23.1405, Flight in icing 

conditions, and their respective means 

of compliance, address NTSB safety 

recommendations A–96–54 and A–96– 

56. The following table provides a 

summary of the proposed icing 

regulations. 

PROPOSED ICING REGULATIONS

Part 23 type certificate limitations Engine protection (§ 23.940) 

Airframe and system protection, performance 

and flight characteristics requirements 

(§§ 23.230, 23.1300, and 23.1405) 

Not certified for flight in icing conditions ............ Safe in part 25, App C conditions, ground ice 

fog, and falling/blowing snow.

None, except pitot heat required if airplane 

certified for flight in instrument meteorological conditions (IMC). 

Certified for flight in icing conditions, but prohibited for flight in SLD.Safe in part 25, App C conditions, ground ice 

fog, and falling/blowing snow.

Safe in part 25, App C conditions. Can detect 

SLD and safely exit. 

Certified for flight in icing conditions and SLD ... Safe in part 25, App C conditions, ground ice 

fog, and falling/blowing snow, and SLD.

Safe in part 25, App C conditions and SLD. 

G. Production of Replacement and 

Modification Articles 

The Part 23 Reorganization ARC 

recommended simplifying certification 

requirements for non-required systems 

and equipment, with an emphasis on 

improvement in overall fleet safety from 

the prevailing level. In the past, the 

FAA has not established different 

production requirements for required 

and non-required equipment that may 

enhance safety, or for articles whose 

improper operation or failure would not 

cause a hazard. The current 

requirements for producing articles and 

representing those articles as suitable 

for installation on type-certificated 

products are well suited for articles 

manufactured in accordance with a 

product’s TC or STC, as well as for TSO 

and PMA parts. However, they may 

unnecessarily constrain the production 

of non-required, low risk articles. 

Current standards for the production 

approval of these articles can create a 

barrier for their installation in the 

existing fleet of aircraft. Examples of 

such articles include carbon monoxide 

detectors, weather display systems, 

clocks, small hand-held fire 

extinguishers, and flashlights. In many 

cases, these articles are ‘‘off-the-shelf’’ 

products. It is frequently difficult for a 

person to install these articles on a typecertificated aircraft because the level of 

design and production details necessary 

for these articles to meet the provisions 

of current § 21.9, as expected for more 

critical articles, are frequently 

unavailable. 

The FAA is therefore proposing to 

revise § 21.9, Replacement and 

Modification Articles, to provide 

applicants with an alternative method to 

obtain FAA approval to produce 

replacement and modification articles. 

This proposed change would allow a 

production approval applicant to submit 

production information for a specific 

article, without requiring the producer 

of the article to obtain approval of the 

article’s design or approval of its quality 

system. The FAA intends to use the 

flexibility provided by this proposal to 

streamline the approval process for nonrequired safety enhancing equipment 

and other articles that pose little or no 

risk to aircraft occupants and the public. 

The FAA requests comments on this 

proposal, and particularly is interested 

in comments regarding whether the 

proposed change would safely facilitate 

retrofit of low risk articles and whether 

there are alternative methods to address 

the perceived retrofit barrier. 

V. Key Terms and Concepts Used in 

This Document 

The proposal includes a number of 

terms introduced into the regulations for 

the first time. These terms may be used 

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to replace existing prescriptive 

requirements or may explain other 

terms that have had longstanding use in 

the aircraft certification process, but in 

context of this rulemaking proposal, the 

FAA wants to specify its meaning. 

These terms are intended to set forth 

and clarify the safety intent of the 

proposed rules. Although certain terms 

may differ from those currently in use, 

these differences are not intended to 

increase the regulatory burden on an 

applicant unless specifically stated. The 

FAA’s intent is that the proposed 

requirements incorporating these new 

terms not change the intent, 

understanding, or implementation of the 

original rule unless that requirement has 

been specifically revised in the 

proposal, such as is the case for 

requirements governing stall 

characteristics. To assist applicants in 

understanding the intent of the 

proposal, these terms are discussed 

below: 

Airplane Certification Level—A 

division used for the certification of 

airplanes that is associated directly with 

the number of passengers on the 

airplane. Airplane certification levels 

would be established to implement the 

agency’s concept of certificating 

airplanes using a process that recognizes 

a safety continuum. 

Airplane Performance Level— 

Maximum airspeed divisions that are 

intended, along with airplane 

certification levels, to replace current 

weight and propulsion divisions used 

for the certification of airplanes. Current 

propulsion-based divisions assume that 

piston engine airplanes are slower than 

turbine-powered airplanes. Current 

weight-based divisions assume that 

heavier airplanes are more complex and 

would be more likely to be used in 

commercial passenger carriage than 

lighter airplanes. These assumptions are 

no longer valid. Airplane certification 

based on performance levels would 

apply regulatory standards appropriate 

to airplane’s performance and 

complexity. 

Departure Resistant—For the 

purposes of this NPRM, departure 

resistant refers to stall characteristics 

that make it very difficult for the 

airplane to depart controlled flight. 

Most fatal stall or spin accidents start 

below 1000 feet above ground level and 

do not actually spin, but start a yawing 

and rolling maneuver to enter the spin 

called a post stall gyration. In these lowaltitude accidents, the airplane typically 

hits the ground before completing one 

turn. Therefore, the important safety 

criterion is preventing the airplane from 

exhibiting stall characteristics that 

could result in a departure from 

controlled flight. 

Entry-Level Airplane—A two or fourplace airplane typically used for 

training, rental, and by flying clubs. 

Historically, most of these airplanes 

have four cylinder engines with less 

than 200 horsepower. These airplanes 

typically have fixed-gear and fixed-pitch 

propellers, but may also have retractable 

landing gear and constant speed 

propellers. Entry-level airplanes 

typically cannot be used to train pilots 

to meet the requirements to operate a 

complex aircraft, as that term is defined 

for airman certification purposes. 

Equivalent Level of Safety (ELOS) 

Finding—A finding made by the 

accountable aircraft certification 

directorate when literal compliance 

with a certification requirement cannot 

be shown and compensating factors in 

the design can be shown to provide a 

level of safety equivalent to that 

established by the applicable 

airworthiness standard. 

Fuel—Any source used by the 

powerplant to generate its power. 

Hazard—Any existing or potential 

condition that can lead to injury, illness 

or death; damage to or loss of a system, 

equipment, or property; or damage to 

the environment. A hazard is a 

condition that is a prerequisite to an 

accident or an incident. (Cf. Order VS 

8000.367, Appendix A) 

Issue Paper—A structured means for 

describing and tracking the resolution of 

significant technical, regulatory, and 

administrative issues that occur during 

a certification project. The issue paper 

process constitutes a formal 

communication vehicle for addressing 

significant issues among an applicant, 

the FAA, and if applicable, the 

validating authority (VA) or certificating 

authority (CA) for type validation 

programs. An issue paper may also be 

used to address novel or controversial 

technical issues. 

Means of Compliance—A 

documented procedure used by an 

applicant to demonstrate compliance to 

a performance or outcome-based 

standard. Similar to an Advisory 

Circular (AC), a means of compliance is 

one method, but not the only method, 

to show compliance with a regulatory 

requirement. Additionally, if a 

procedure is used as a means of 

compliance, it must be followed 

completely to maintain the integrity of 

the means of compliance. 

Performance- or Outcome-Based 

Standard—A standard that states 

requirements in terms of required 

results, but does not prescribe any 

specific method for achieving the 

required results. A performance-based 

standard may define the functional 

requirements for an item, operational 

requirements, or interface and 

interchangeability characteristics. 

Pilot or Flightcrew—This is used 

generically throughout the proposed 

part 23 because part 23 has airplanes 

approved for single pilot operations as 

well as and two flightcrew members. 

For most airplanes certificated under 

part 23 that are single pilot, applicants 

should consider pilot and flightcrew to 

be interchangeable. 

Prescriptive Design Standard— 

Specifies a particular design 

requirement, such as materials to be 

used, how to perform a test, or how an 

item is to be fabricated or constructed. 

(Cf. OMB Circular A–119 Section 5.f.) 

Safety Continuum—The concept that 

one level of safety is not appropriate for 

all aviation activities. Accordingly, 

higher levels of risk, with corresponding 

requirements for less rigorous safety 

demonstrations for products, are 

accepted as aircraft are utilized for more 

personal forms of transportation. 

Survivable Volume—The airplane 

cabin’s ability to resist external 

intrusion or structural collapse during 

and after impact. The ability to resist is 

usually represented as a stiffer design 

around the cabin (not unlike a racecar 

roll cage) that is generally stronger than 

the surrounding structure. While the 

airframe may deform or disintegrate and 

attenuate impact energy, the cabin of the 

airplane will still maintain its integrity 

and protect the occupants restrained 

within. During otherwise survivable 

accident scenarios, including rollover, 

this structure should maintain its shape 

under static and dynamic loading 

conditions. 

VI. Discussion of the Proposed 

Regulatory Amendments 

A. Part 23, Airworthiness Standards 

1. Subpart A—General 

a. General Discussion 

The FAA proposes eliminating the 

utility, acrobatic, and commuter 

categories for future airplanes 

certificated under part 23. The FAA also 

proposes to change from weight and 

propulsion divisions to performance 

and risk divisions. This would address 

the wide range of airplanes to be 

certificated under part 23 and enhance 

application of the safety continuum 

approach. Appendix 1 of this preamble 

contains a cross-reference table detailing 

how the current regulations are 

addressed in the proposed part 23 

regulations. 

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b. Specific Discussion of Changes 

i. Proposed § 23.1, Applicability and 

Definition 

Proposed § 23.1 would prescribe 

airworthiness standards for the issuance 

of type certificates, and changes to those 

certificates, for airplanes in the normal 

category. Current § 23.3, Airplane 

categories, defines normal category as 

airplanes that have a seating 

configuration, excluding pilot seats, of 

nine or less, a maximum certificated 

takeoff weight of 12,500 pounds or less, 

and intended for nonacrobatic 

operation. Proposed § 23.1 would delete 

references to utility, acrobatic, and 

commuter category airplanes, and 

paragraph (b) would not include the 

current reference to procedural 

requirements for showing compliance. 

The reference to procedural 

requirements for showing compliance is 

redundant with the requirement in 

§ 21.21, Issue of type certificate: Normal, 

utility, acrobatic, commuter, and 

transport category aircraft; manned free 

balloons; special classes of aircraft; 

aircraft engines; propellers, to show 

compliance. Proposed § 23.1 would also 

add three definitions specific to part 23: 

(1) Continued safe flight and landing, (2) 

designated fire zone, and (3) empty 

weight. 

ii. Proposed § 23.5, Certification of 

Normal Category Airplanes 

Proposed § 23.5 would apply 

certification in the normal category to 

airplanes with a passenger-seating 

configuration of 19 or less and a 

maximum certificated takeoff weight of 

19,000 pounds or less. Proposed § 23.5 

would also establish certification levels 

based on the passenger seating 

configuration and airplane performance 

levels based on speed. 

The diversity of airplanes certificated 

under part 23 is large relative to 

performance, numbers of passengers, 

complexity, technology, and intended 

use. Airplane certification requirements 

under part 23 are currently determined 

using a combination of weight, numbers 

of passengers, and propulsion type. 

These divisions historically were 

appropriate because there was a clear 

relationship between the propulsion 

and weight of the airplane and its 

associated performance and complexity. 

Recent technological developments 

have altered the dynamics of this 

relationship. High-performance and 

complex airplanes now exist within the 

weight range that was typical for light 

and simple airplanes. Furthermore, 

current part 23 has evolved to meet the 

additional regulatory requirements 

resulting from the introduction of highperformance airplanes. This has 

resulted in the introduction of more 

stringent and demanding requirements 

in the lower weight airplanes such as 

the use of 14 CFR part 25 based 

requirements for simple, single-engine 

turbine airplanes. The result is that 

some of the current requirements have 

become more demanding for simple and 

low-performance airplanes. 

The FAA proposes replacing the 

current part 23 weight and propulsion 

divisions because they were based on 

assumptions that do not always fit the 

large diversity of airplane performance, 

complexity, technology, intended use, 

and seating capacity encompassed in 

today’s new airplane designs. Also, the 

current divisions may not be 

appropriate to address unforeseen 

designs of the future. The commuter 

category, originally intended for the 

certification of airplanes over 12,500 

pounds and up to 19 passengers, is 

currently used for larger business jets 

with less than ten passengers. The 

proposed certification and performance 

level approach, while different from the 

current divisions, would capture the 

safety intent of part 23 more 

appropriately than the current 

propulsion and weight divisions. 

The FAA proposes replacing the 

current divisions with specific technical 

and operational capabilities by 

addressing, for example, stall speed, 

VFR/IFR operation, pressurization, etc., 

that represent the actual technical 

drivers for current prescriptive 

requirements. These types of design 

specific technical and operational 

criteria would be more appropriate for 

a means of compliance document where 

a complete range of airplane designs 

could be addressed. The FAA proposes 

that high-speed, multiengine airplanes 

and multiengine airplanes over 12,500 

pounds should continue meeting the 

equivalent commuter category 

performance-based requirements. The 

proposed performance requirements 

would be based on number of 

passengers (certification level) and 

airplane performance (performance 

level); not weight or propulsion type. 

The FAA proposes to eliminate 

commuter, utility, and acrobatic 

airplane categories in part 23, retaining 

only normal category for all new part 23 

type certificated airplane design 

approvals. The FAA believes this action 

would not affect the existing fleet of 

small airplanes. For example, the 

commuter category was originally 

introduced into part 23 to apply to a 10 

to 19 passenger, multiengine airplane, 

operated in scheduled service under 14 

CFR parts 121 and 135. However, new 

airplanes certified under part 23 can no 

longer be used in scheduled service 

under part 121 because § 121.157, 

Aircraft certification and equipment 

requirements, paragraph (h), requires a 

part 25 certification for newly type 

certificated airplanes. The majority of 

airplanes recently certified in the 

commuter category are multiengine 

business jets. Additionally, the 

certification category of commuter can 

be confused with the same term in the 

operating rules because the term is 

defined differently in the certification 

and operation rules. The FAA 

recognizes that moving away from 

weight and propulsion divisions would 

result in changes for the criteria used to 

determine when to apply the existing 

commuter category certification 

requirements using the numbers of 

passenger seats (excluding crewmember 

seats), performance, and technical 

divisions proposed in this NPRM. The 

FAA proposes the following airplane 

certification levels: 

• Level 1—for airplanes with a maximum 

seating configuration of 0 to 1 passengers. 

• Level 2—for airplanes with a maximum 

seating configuration of 2 to 6 passengers. 

• Level 3—for airplanes with a maximum 

seating configuration of 7 to 9 passengers. 

• Level 4—for airplanes with a maximum 

seating configuration of 10 to 19 passengers. 

The differences between normal, 

utility, and acrobatic categories are 

currently very limited and primarily 

affect airframe structure requirements. 

Proposed part 23 would still allow a 

normal category airplane to be approved 

for aerobatics provided the airplane was 

certified to address the factors affecting 

safety for the defined limits for that kind 

of operation. Currently, the utility 

category provides airplanes additional 

margin for the more stringent inertial 

structural loads resulting from intended 

spins and the additional maneuvers 

stated in the requirements of the utility 

category in § 23.3(b). The FAA proposes 

that airplanes approved for spins be 

certificated to aerobatic standards. An 

airplane designed with traditional 

handling qualities and designed to 

allow spin training is more susceptible 

to inadvertent departure from controlled 

flight. The FAA believes that 

maintaining the current utility category 

for airplanes approved for spins and 

limited aerobatic maneuvers would 

negate the single largest safety gain 

expected from this rulemaking action— 

the significant reduction in inadvertent 

stall-related departures from controlled 

flight. 

Proposed § 23.5(c) would categorize 

the performance level of an airplane as 

low speed or high speed. The 

combination of certification levels and 

performance levels is intended to 

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provide divisions that address the actual 

safety concern of occupant numbers and 

performance, for example, future 

designs using novel propulsion 

methods. The FAA proposes the 

following airplane performance levels: 

• Low speed—for airplanes with a design 

cruising speed (VC) or maximum operating 

limit speed (VMO) ≤ 250 KCAS (or MMO ≤ 

0.6). 

• High speed—for airplanes with a VC or 

VMO > 250 KCAS (or MMO > 0.6). 

Proposed § 23.5(d) would identify a 

simple airplane as one with a 

certification level 1, a VC or VMO ≤ 250 

KCAS (and MMO ≤ 0.6), and a VSO ≤ 45 

KCAS, and approved only for VFR 

operations. The FAA proposes a simple 

airplane as equivalent to airplanes 

certificated under EASA’s current CS– 

VLA. In most cases, EASA’s CS–VLA 

requirements are identical to the 

proposed corresponding part 23 

requirements and have been proposed 

in the requirements for certification 

level 1 airplanes. The FAA considered 

using the CS–VLA standards in 

combination with the proposed part 23 

certification standards for all 

certification level 1, low-speed 

airplanes. However, the FAA believes 

that there are several requirements in 

CS–VLA that are not appropriate for all 

certification level 1, low-speed 

airplanes, such as no requirement for a 

type certified engine in CS–VLA. 

Therefore, the FAA proposes creating a 

limited certification and performance 

level for simple airplanes. Simple 

airplanes would be a subset of 

certification level 1, low-speed airplanes 

and would have a VSO ≤ 45 KCAS and 

would only be approved for VFR 

operations. 

In accordance with the FAA’s 

objective to remove weight and 

propulsion divisions from the rules and 

use performance and certification 

divisions, the proposed requirements 

applicable to the certification of simple 

airplanes would not completely 

conform to the criteria EASA uses to 

certificate very light airplanes. The FAA 

proposes that simple airplanes would 

constitute a subset of certification level 

1, low-speed airplanes that would be 

required to have a low stall speed limit 

and a VFR limitation in order to 

maintain a level of safety appropriate for 

these airplanes. The FAA believes that 

creating the simple certification level 

would encourage manufacturers of lightsport and experimental aircraft kits to 

pursue type certificates for their 

airplane designs without encountering 

the administrative, procedural or 

regulatory barriers existing in current 

part 23, while allowing innovative 

technology in those designs. 

The FAA considered allowing 

airplanes that meet the consensus 

standards applicable to the certification 

of special light-sport aircraft to be 

included in proposed part 23. However, 

the FAA decided that this would not be 

in the best interest of the GA 

community because it could result in 

the elimination of the special light-sport 

aircraft category. There are advantages 

in the certification of special light-sport 

aircraft, such as self-certification, that 

would not be available if the aircraft 

were type certificated under part 23. 

This proposal would instead enable a 

simpler path to part 23 certification for 

airplanes that meet the definition of a 

light-sport aircraft and wish to pursue a 

type of certificate for business reasons. 

The FAA expects simple airplanes to 

be more basic than the proposed 

certification level 1, low-speed 

airplanes. A simple airplane is a 

certification level 1, low-speed airplane 

with a stall speed limit of 45 KCAS that 

would be limited to VFR operations. 

The FAA recognizes that a simple 

airplane level would have 

characteristics very similar to 

certification level 1, low-speed 

airplanes, and that creating this category 

may be unnecessary. For this reason, the 

FAA is specifically asking for comments 

concerning the value of creating a 

separate, simple airplane level. 

iii. Proposed § 23.10, Accepted Means of 

Compliance 

Proposed § 23.10 would require an 

applicant to show the FAA how it 

would demonstrate compliance with 

this part using a means of compliance, 

which may include consensus 

standards, accepted by the 

Administrator. Proposed § 23.10 would 

also require an applicant requesting 

acceptance of a means of compliance to 

provide the means of compliance to the 

FAA in a form and manner specified by 

the Administrator. 

Proposed § 23.10 would create 

flexibility for applicants in developing 

means of compliance and also 

specifically identify consensus 

standards as a means of compliance the 

Administratory may find acceptable. 

The Part 23 Reorganization ARC 

proposed using consensus standards for 

the detailed means of compliance to the 

fundamental safety requirements in 

proposed part 23. As discussed in the 

International Harmonization Efforts 

section of this NPRM, the intent of this 

proposal is to create a regulatory 

architecture for part 23 that is agile 

enough to keep up with innovation. 

Allowing the use of consensus 

standards would accomplish this goal. 

The Part 23 Reorganization ARC 

recommended creating this proposed 

section to identify specifically the 

means of compliance documents 

developed by industry, users such as 

large flight schools, the interested 

public, and the FAA, that an applicant 

could use in developing a certification 

application. The ARC expressed two 

concerns that led to the creation of the 

proposed requirement. First, applicants 

need to use a means of compliance 

accepted by the Administrator when 

showing compliance to part 23. Second, 

while a consensus standards body (i.e., 

ASTM, SAE, RTCA, etc.) developed 

means of compliance document may be 

available, individuals or organizations 

may also submit their own means of 

compliance documentation to the 

Administrator for consideration and 

potential acceptance. Additionally, the 

FAA wants to ensure applicants 

understand that an applicant-developed 

means of compliance document would 

require FAA review and acceptance by 

the Administrator. 

The FAA anticipates that individuals 

or organizations would develop 

acceptable means for complying with 

the proposed performance standards. A 

standards organization such as ASTM, 

for example, could generate a series of 

consensus-based standards for review, 

acceptance, and public notice of 

acceptance by the FAA. The ASTM 

standards could be one way, but not the 

only way, to demonstrate compliance 

with part 23. Other consensus standard 

bodies such as RTCA and SAE are 

currently focused on developing 

standards for aircraft components and 

appliances. 

The proposed airworthiness standards 

would allow airplanes to be certificated 

at different airplane certification levels. 

For example, software integrity levels 

appropriate for a certification level 1 

airplane may not be appropriate for a 

certification level 4 airplane. 

Additionally, the takeoff performance of 

an airplane might be evaluated 

differently for an airplane intended to 

be certificated at different airplane 

certification levels. An applicant 

seeking certification of a certification 

level 1 airplane with a takeoff distance 

of 200 feet, for example, would not need 

to establish the takeoff distance with the 

same degree of accuracy as would an 

applicant seeking certification of a 

certification level 4 high-speed airplane 

with a takeoff distance of 4,000 feet. 

By using means of compliance 

documents to show compliance with the 

proposed performance-based rules, the 

need for special conditions, ELOS 

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19See www.regulations.gov (Docket # FAA–2015– 

1621). 

findings, and exemptions to address 

new technology advancements would 

diminish. Once the Administrator 

accepted a means of compliance, it may 

be used for future applications for 

certification unless formally rescinded. 

Allowing the use of consensus 

standards as a means of compliance to 

performance-based regulations would 

provide the FAA with the agility 

necessary to more rapidly accept new 

technology, leverage industry 

expectations in the development of new 

means of compliance documents, and 

provide for the use of harmonized 

means of compliance among the FAA, 

industry, and foreign CAAs. While an 

applicant would not be required to use 

previously accepted means of 

compliance documents, their use would 

streamline the certification process by 

eliminating the need to develop an issue 

paper to address the certification of new 

technology. Proposed AC 23.10,19

Accepted Means of Compliance, would 

provide guidance for applicants on the 

process applicants would follow to 

submit proposed means of compliance 

to the FAA for consideration by the 

Administrator. 

The Part 23 Reorganization ARC 

expressed concerns that a consensus 

standard could be biased in favor of a 

few large manufacturers and would 

create an unfair competitive advantage. 

The FAA notes that any interested party 

may participate in the ASTM 

committees developing consensus 

standards thereby, mitigating this 

concern. The FAA expects that other 

consensus standards bodies would 

allow similar opportunities for 

interested parties to participate in their 

standards development work. 

Additionally, any individual or 

organization could develop its own 

means of compliance and submit it to 

the FAA for acceptance by the 

Administrator. The other risk identified 

by the Part 23 Reorganization ARC was 

that specialists in the industry could 

argue for complex means of compliance 

when the FAA would accept a simpler 

or more cost effective approach. 

However, the FAA would continue to 

allow applicants to propose their own 

means of compliance when the larger 

industry standard may be the 

appropriate level of safety for one, but 

not all certification levels. Lastly, the 

FAA intends to continue to allow the 

use of the current prescriptive means of 

compliance contained in current part 23 

requirements as one obvious alternative 

to showing compliance with proposed 

part 23. This would not apply to the 

proposed sections that contain new 

requirements, such as §§ 23.200, 23.215, 

and 23.230. 

The Part 23 Reorganization ARC also 

was aware the Administrator has 

accepted various manufacturers’ 

internal standards in the past and 

recommended having that option stated 

in the proposal. Proposed § 23.10 would 

allow applicants to submit their internal 

standards as means of compliance for 

consideration by the Administrator. 

iv. Removal of Subpart A Current 

Regulations 

The FAA proposes removing current 

§ 23.2, Special retroactive requirements, 

from part 23 because the operational 

rules currently address these 

requirements. The current retroactive 

rule is more appropriate in the operating 

rules. The FAA proposes amending 14 

CFR part 91, as discussed later in the 

Discussion of the Proposed Regulatory 

Amendments to ensure removing the 

current § 23.2 requirement would not 

affect the existing fleet. 

2. Subpart B—Flight 

a. General Discussion 

The FAA proposes moving away from 

the current stall characteristics and spin 

testing approach to address the largest 

cause of fatal accidents in small 

airplanes. Proposed § 23.215 in subpart 

B would omit the one turn/three second 

spin requirement for normal category 

airplanes, but it would increase the stall 

handling characteristics and stall 

warning requirements so the airplane 

would be substantially more resistant to 

stall-based departures than the current 

rules require. 

The FAA also proposes eliminating 

the utility, acrobatic, and commuter 

categories in part 23. Accordingly, a 

new airplane would have to be 

approved for aerobatic loads as the 

normal category, even if an applicant 

only wanted to spin the airplane. 

Therefore, the FAA proposes to restrict 

certification of new airplanes for dual 

use, which can be done today using 

both the normal and utility categories. 

The FAA believes that if the airplane 

can spin for spin training, then the 

airplane can inadvertently stall and 

depart into a spin during normal 

operations. One of the FAA’s goals is to 

prevent inadvertent stalls, so allowing 

airplanes that are commonly used as 

rental airplanes to spin would defeat the 

goal. However, the FAA would consider 

accepting a dual-purpose airplane if the 

airplane manufacturer provided a 

system that could be changed 

mechanically or electronically from 

normal to aerobatic as a maintenance 

function rather than controlled by the 

pilot. 

The FAA proposes consolidating the 

performance requirements for highspeed multiengine airplanes and 

multiengine airplanes that weigh over 

12,500 pounds. These airplanes are 

currently required to meet a series of 

one-engine-inoperative climb gradients. 

These climb gradients were based on 

part 25 requirements and intended for 

commuter category airplanes used in 

scheduled air service under parts 135 

and 121. New airplanes certificated 

under part 23 are not eligible for 

operation in scheduled service under 

part 121, diminishing the utility of the 

commuter category for these airplanes. 

More recently, part 23 multiengine 

jets intended to be used under parts 91 

or 135 have been certificated in the 

commuter category, using part 25 based 

climb gradient requirements. In the 

spirit of the proposed rule change, the 

FAA has decided that the one-engineinoperative climb requirements would 

be independent of the number of 

engines and some of the original 

requirements would be consolidated 

into a single requirement that would 

require performance very close to what 

is required today. This action intends to 

maintain the performance capabilities 

expected in 14 CFR part 135 operations. 

The FAA proposes changes in the 

flight characteristics rules to keep the 

safety intent of the existing 

requirements consistent with the other 

proposed part 23 sections. The current 

part 23 requirements are based on small 

airplanes, designed with reversible 

controls, which include some 

accommodations for stability 

augmentation and autopilots. The FAA 

believes the proposed language would 

capture the current requirements for 

flight characteristics and allows for 

varying degrees of automated flight 

control systems in the future. 

Finally, the FAA proposes adding a 

requirement to require certification 

levels 1 and 2 multiengine airplanes, 

not capable of climbing after a critical 

loss of thrust, to stall prior to reaching 

the minimum directional control speed 

(VMC). 

b. Specific Discussion of Changes 

i. Proposed § 23.100, Weight and Center 

of Gravity 

Proposed § 23.100 would require an 

applicant to determine weights and 

centers of gravity that provide limits for 

the safe operation of the airplane. 

Additionally, it would require an 

applicant to show compliance with each 

requirement of this subpart at each 

combination of weight and center of 

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gravity within the airplane’s range of 

loading conditions using tolerances 

acceptable to the Administrator. 

Proposed § 23.100 would also require 

the condition of the airplane at the time 

of determining its empty weight and 

center of gravity to be well defined and 

easily repeatable. 

Proposed § 23.100 would capture the 

safety intent of current §§ 23.21, Proof of 

compliance; 23.23, Load distribution 

limits; 23.25, Weight limits; 23.29, 

Empty weight and corresponding center 

of gravity; and 23.31, Removable ballast. 

This proposed section would ensure an 

applicant considers the important 

weight and balance configurations that 

influence performance, stability, and 

control when showing compliance with 

the flight requirements. The main safety 

requirements of current §§ 23.21–23.31 

are located in current §§ 23.21 and 

23.23. Current § 23.21 allows for a range 

of loading conditions shown by test or 

systematic investigation. The proposed 

rule would still allow for this flexibility, 

including the tolerances for flight test. 

Sections 23.25–23.31 provide 

definitions and directions for 

determining weights and centers of 

gravity and provides directions for 

informing the pilot. For these reasons, 

the information in these sections is 

more appropriate as a means of 

compliance. 

ii. Proposed § 23.105, Performance 

Proposed § 23.105 would require an 

airplane to meet the performance 

requirements of this subpart in various 

conditions based on the airplane’s 

certification and performance levels for 

which certification is requested. 

Proposed § 23.105 also would require an 

applicant to develop the performance 

data required by this subpart for various 

conditions, while also accounting for 

losses due to atmospheric conditions, 

cooling needs, and other demands on 

power sources. Finally, proposed 

§ 23.105 would require the procedures 

used for determining takeoff and 

landing distances to be executed 

consistently by pilots of average skill in 

atmospheric conditions expected to be 

encountered in service. 

Proposed § 23.105 would capture the 

safety intent of current § 23.45, 

Performance—General. The safety intent 

of § 23.45(a) is captured in proposed 

§ 23.105(a) and is essentially unchanged 

from the current rule, except to 

incorporate the proposed certification 

levels and speed divisions. 

Proposed § 23.105(b) would capture 

the safety intent of § 23.45(b) by 

retaining § 23.45(b)(1) requirements and 

combining § 23.45(b)(2) and (b)(3) and 

allowing all airplanes to use the cooling 

climb limits as their upper temperature. 

The level of safety remains the same as 

the current part 23 because part 23 

airplane pilots only have the limitations 

identified in the airplane flight manual, 

including engine temperature limits. 

Proposed § 23.105(c) would also 

capture the safety intent of § 23.45(f). 

The safety intent of the current rule is 

to ensure an average pilot can 

consistently get the same results as 

published in the Airplane Flight Manual 

(AFM). The FAA believes this 

requirement would ensure applicants 

either perform their performance tests in 

a conservative manner or add margins 

and procedures to the AFM performance 

section so an average pilot can achieve 

the same performance. 

Proposed § 23.105(d) would require 

performance data to account for losses 

due to atmospheric conditions, cooling 

needs, and other demands. The current 

rule specifies the position of cowl flaps 

or other means for controlling the 

engine air supply. The proposed 

language accounts for airplane 

performance, if affected by the cooling 

needs of the propulsion system, which 

is the safety intent of § 23.45, but would 

omit the details because they are more 

appropriate as a means of compliance. 

Proposed § 23.105(d) would also 

capture the safety intent § 23.45(d) and 

(e). The safety intent of the current rule 

is to ensure the airplane performance 

accounts for minimum power available 

from the propulsion system, considering 

atmospheric and cooling conditions and 

accessories requiring power. 

iii. Proposed § 23.110, Stall Speed 

Proposed § 23.110 would require an 

applicant to determine the airplane stall 

speed or the minimum steady flight 

speed for each flight configuration used 

in normal operations, accounting for the 

most adverse conditions for each flight 

configuration, with power set at idle or 

zero thrust. 

Proposed § 23.110 would capture the 

safety intent of current § 23.49, Stalling 

speed. Stall speeds are necessary to 

define operating and limiting speeds 

used to determine airplane performance. 

They also provide a basis for 

determining kinetic energy in 

emergency landing conditions. 

Therefore, determining stall speeds is 

required in the configurations used in 

the operation of the airplane. 

The FAA proposes removing the 61- 

knot stall speed division for singleengine airplanes from the rules because 

this speed has not been a limitation 

since 1992 with the addition of the 

options for stall speeds in excess of 61 

knots in § 23.562, Emergency landing 

dynamic conditions. Therefore, the 61- 

knot stall speed is a technical division 

rather than a limitation and would be 

more appropriate as a means of 

compliance. 

The FAA is changing its approach to 

crashworthiness. Instead of constraining 

the connection between stall speed and 

crashworthiness to a single fixed speed, 

the FAA proposes allowing alternative 

approaches to crashworthiness. The 

intent is to encourage incorporation of 

innovations from other industries to 

provide more occupant protection in the 

airframe. This approach would base 

occupant protection on the actual stall 

speed rather than a single mandated 

stall speed. 

iv. Proposed § 23.115, Takeoff 

Performance 

Proposed § 23.115 would require an 

applicant to determine airplane takeoff 

performance, which includes the 

determination of ground roll and initial 

climb distance to 50 feet, accounting for 

stall speed safety margins, minimum 

control speeds; and climb gradients. 

Proposed § 23.115 would also require 

the takeoff performance determination 

to include accelerate-stop, ground roll 

and initial climb to 50 feet, and net 

takeoff flight path, after a sudden 

critical loss of thrust for certification 

levels 1, 2, and 3 high-speed 

multiengine airplanes, multiengine 

airplanes with a maximum takeoff 

weight greater than 12,500 pounds, and 

certification level 4 multiengine 

airplanes. 

Proposed § 23.115 would capture the 

safety intent of current §§ 23.51, Takeoff 

speeds; and 23.61, Takeoff flight path. 

Takeoff distance information and the 

associated procedures for achieving 

those distances are necessary for the 

safe operation of all airplanes certified 

under part 23. Proposed § 23.115 would 

require applicants to determine, 

develop, and publish distance and 

procedure data for the pilot to use. The 

effects of airplane weight, field 

temperature and elevation, winds, 

runway gradient, and runway surface 

also need to be available to the pilot 

because they affect airplane 

performance. For proposed simple 

entry-level airplanes, conservative 

analysis may supplement flight test 

while data for larger, higher 

performance airplanes are expected to 

provide the level of precision that is 

accepted today. 

Additionally, proposed § 23.115 

would require applicants to determine 

critical thrust loss cases for multiengine 

airplanes. Today, the loss of one engine 

on a two-engine airplane is the standard 

model. The future possibilities for the 

functions of engines, if different from 

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thrust, and how the engines are 

controlled, may determine critical thrust 

loss. For example, a large number of 

engines along the leading edge of a wing 

could function as a high-lift device as 

well as provide thrust. 

Historically, limited propulsion 

options and the need for inherent 

stability from reversible, mechanical 

control systems have restrained airplane 

configurations. The FAA anticipates 

that new propulsion systems and 

affordable electronic flight control 

systems will challenge these traditional 

designs and need alternative means of 

compliance. Speed multiples and 

factors used in current part 23 

prescriptive requirements are based on 

traditional airplane configurations. Part 

23 mandates these details of design for 

compliance. The FAA believes 

removing these details would provide 

applicants with the agility and 

flexibility to address these new airplane 

configurations. The current factors will 

still apply for traditional configurations, 

but proposed performance-based 

requirements should allow rapid 

adoption of new means of compliance 

for future airplane configurations. 

The FAA proposes removing airplane 

categories and weight and propulsion 

certification divisions for multiengine 

jets over 6,000 pounds and replacing 

them with divisions based on risk and 

performance. The commuter category, 

originally intended for the certification 

of airplanes over 12,500 pounds and up 

to 19 passengers, is currently used for 

larger business jets with less than ten 

passengers. The FAA proposes that 

high-speed, multiengine and 

multiengine airplanes over 12,500 

pounds should continue meeting the 

equivalent commuter category 

performance-based requirements. The 

historical assumption applied to jets 

was that they were fast, had high wing 

loadings, and used significant runway 

distances for takeoff and landing. 

Therefore, all jets were required to have 

guaranteed climb performance with one 

engine inoperative. This requirement 

does not currently apply to single 

engine jets. The proposed performance 

requirements would be based on 

number of passengers (certification 

level) and airplane performance 

(performance level), not weight or 

propulsion type. The proposed 

certification and performance levels 

approach would not offer a one-to-one 

relationship with the current 

requirements. A low-speed turbinepowered airplane may be more 

appropriately addressed by regulations 

currently applicable to piston-powered 

airplanes, while a piston-powered or a 

high-speed electric airplane may be 

more appropriately addressed by 

regulations currently used for the 

certification of turbine-powered 

airplanes. The proposed certification 

and performance level approach, while 

different from the current divisions, 

would capture the safety intent of part 

23 more appropriately than the current 

propulsion and weight divisions. 

v. Proposed § 23.120, Climb 

Requirements 

Proposed § 23.120 would require an 

applicant to demonstrate various 

minimum climb performances out of 

ground effect, depending on the 

airplane’s certification level, engines, 

and performance capability. This new 

provision would capture the safety 

intent of current §§ 23.65, Climb: All 

engines operating; 23.67, Climb: One 

engine inoperative; and 23.77, Balked 

landing. Minimum climb performance 

information is necessary so pilots can 

determine if they have adequate 

clearance from obstacles beyond the end 

of the runway. New engine 

technologies, especially electric, would 

allow for alternative configurations that 

would invalidate many of the detailed 

test configuration and power 

assumptions that are in the current 

requirements. 

Part 23 currently has a large matrix for 

all the climb requirements that includes 

category, weight, and number of 

engines, resulting in over 20 different 

climb gradient requirements. This 

reflects the growth in the variety of 

different airplane types that has 

occurred since the certification 

regulations were first adopted in CAR 3. 

Because the FAA proposes simplifying 

these divisions using certification levels 

and airplane performance levels, it can 

eliminate required climb gradients for 

three and four engines. The FAA 

proposes basing multiengine climb 

gradients on critical loss for thrust and 

using the gradient for the current twinengine airplanes because it has resulted 

in a safe service history. The FAA 

proposes replacing the term ‘‘failure of 

the critical engine’’ (which addresses a 

twin engine airplane) with ‘‘critical loss 

of thrust’’ for airplanes certificated 

under those provisions. The reason for 

replacing this term is that with 

configurations utilizing large numbers 

of engines, the failure modes may not 

follow the traditional failure modes as 

with the loss of one engine on a twoengine airplane. Furthermore, the FAA 

proposes retaining and consolidating 

the climb gradients from current § 23.67 

because these gradients are important 

minimum performance requirements for 

maintaining the current level of safety. 

Proposed § 23.120(a) would capture 

the safety intent of current § 23.65. It 

would retain the existing climb 

gradients and atmospheric conditions 

required for pilot planning. 

Proposed § 23.120(b) would capture 

the safety intent of current § 23.67, and 

consolidates the weight and propulsion 

divisions into all engines operating, 

critical loss of thrust, and balked 

landing groups. Furthermore, for highspeed airplanes, after a critical loss of 

thrust, the FAA proposes reducing the 

number of required climb conditions for 

certification to one gradient at 400 feet 

(122 meters) above the takeoff surface. 

For the typical part 23 certified twinengine airplane, the required climb 

gradient at 400 feet (122 meters) above 

the takeoff surface is generally the most 

challenging. Airplanes that have the 

performance to meet this one 

requirement typically can meet all the 

current requirements. For certification 

levels 3 and 4, high-speed multiengine 

airplanes, the FAA proposes 

consolidating the configurations 

currently prescribed for the second 

segment climb and a discontinued 

approach. The climb gradient difference 

between these segments is 0.1 percent 

and uses the takeoff flap configuration 

rather than the approach flap 

configuration. Requiring only one climb 

gradient at 400 feet (122 meters) above 

the takeoff surface with the landing gear 

retracted and flaps in the approach 

position would maintain the current 

level of safety while reducing the 

requirements by eliminating initial, 

final, and discontinued approach climb 

tests. Because the proposed 

requirements would reduce the amount 

of climb testing for designs intended for 

use under part 91, applicants would 

also need to provide the traditional 

operational performance data, as is 

currently done, if the design is intended 

to be used for commercial operations 

under part 135 operating rules. 

The FAA also proposes to normalize 

the initial climb height to 50 feet (15 

meters) above the takeoff surface. The 

regulations for the certification of 

commuter category airplanes essentially 

adopted many of the part 25 climb 

requirements, including an initial climb 

height of 35 feet (11 meters) above the 

takeoff surface. When the commuter 

category was adopted, the expectation 

was that these airplanes would be used 

in part 121 service. This expectation 

allowed the FAA to accept the part 25 

assumption that takeoff distances would 

be factored; thus, providing a safety 

margin to offset the lower initial climb 

height. Part 23 requirements provide 

minimum safe operations for part 91, 

which does not require factored takeoff 

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distances. Therefore, allowing a 35 foot 

(11 meters) height above the takeoff 

surface is a lower safety margin than 

used for smaller airplanes and, for this 

reason, the FAA proposes to make all 

airplanes certificated under part 23 use 

50 feet (15 meters) above the takeoff 

surface. 

vi. Proposed § 23.125, Climb 

Information 

Proposed § 23.125 would require an 

applicant to determine the climb 

performance for— 

• All single engine airplanes; 

• Certification level 3 multiengine 

airplanes after a critical loss of thrust on 

takeoff in the initial climb 

configuration; and 

• All multiengine airplanes during 

the enroute phase of flight with all 

engines operating and after a critical 

loss of thrust in the cruise configuration. 

Proposed § 23.125 would also require 

an applicant to determine the glide 

performance of the airplane after a 

complete loss of thrust for single engine 

airplanes. 

Proposed § 23.125 would capture the 

safety intent of current §§ 23.63, Climb: 

General; 23.66, Takeoff climb: Oneengine inoperative; 23.69, Enroute 

climb/descent; and 23.71, Glide: Singleengine airplanes. The intent of these 

requirements is to provide pilots with 

climb and glide performance data that is 

important for safety, especially in 

conditions near the performance limits 

of the airplane. Sections 23.63, 23.66, 

and 23.69 are not minimum 

performance sections, but contain 

information used in the development of 

the AFM. Proposed § 23.125 would 

require an applicant to determine climb 

performance. The performance data 

determination provides a good example 

of how the use of certification levels can 

allow simplified approaches to meet 

applicable airworthiness requirements 

for simple, and levels 1 and 2 airplanes. 

vii. Proposed § 23.130, Landing 

Proposed § 23.130 would require an 

applicant to determine the landing 

distance for standard temperatures at 

each weight and altitude within the 

operational limits for landing. The 

landing distance determination would 

start from a height of 50 feet (15 meters) 

above the landing surface, require the 

airplane to land and come to a stop (or 

for water operations, reach a speed of 3 

knots) using approach and landing 

speeds, configurations, and procedures, 

which allow a pilot of average skill to 

meet the landing distance consistently 

and without causing damage or injury. 

Proposed § 23.130 would require these 

determinations for standard 

temperatures at each weight and 

altitude within the operational limits for 

landing. 

Proposed § 23.130 would capture the 

safety intent of current § 23.73, 

Reference landing approach speed, and 

§ 23.75, Landing Distance. Landing 

distance information and the associated 

procedures for achieving those distances 

are necessary to prevent runway 

overruns. Applicants would be required 

to determine, develop, and publish 

distance and procedures data for use in 

pilot planning. Proposed § 23.130 would 

combine the current requirements to 

determine approach speed and landing 

distance because a determination of 

both is required for a landing distance 

determination. 

viii. Proposed § 23.200, Controllability 

Proposed § 23.200 would require the 

airplane to be controllable and 

maneuverable, without requiring 

exceptional piloting skill, alertness, or 

strength, within the operating envelope, 

at all loading conditions for which 

certification is requested. This would 

would include during low-speed 

operations, including stalls, with any 

probable flight control or propulsion 

system failure, and during configuration 

changes. Proposed § 23.200 would 

require the airplane to be able to 

complete a landing without causing 

damage or serious injury, in the landing 

configuration at a speed of VREF minus 

5 knots using the approach gradient 

equal to the steepest used in the landing 

distance determination. Proposed 

§ 23.200 would require VMC not to 

exceed VS1 or VS0 for all practical 

weights and configurations within the 

operating envelope of the airplane for 

certification levels 1 and 2 multiengine 

airplanes that cannot climb after a 

critical loss of thrust. Proposed § 23.200 

would also require an applicant to 

demonstrate those aerobatic maneuvers 

for which certification is requested and 

determine entry speeds. 

Proposed § 23.200 would capture the 

safety intent of §§ 23.141, Flight 

Characteristics—General, 23.143, 

Controllability and Maneuverability— 

General; 23.145, Longitudinal control; 

23.147 Directional and lateral control; 

23.149, Minimum control speed; 23.151, 

Acrobatic maneuvers; 23.153, Control 

during landing; 23.155, Elevator control 

force in maneuvers; 23.157, Rate of roll; 

23.697(b) and (c), Wing flap controls. 

Proposed § 23.200 would ensure the 

maneuvering flight characteristics of the 

airplane are safe and predictable 

throughout the flight envelope and 

result in repeatable, smooth transitions 

between turns, climbs, descents, and 

level flight. Configuration changes, such 

as flap extension and retraction, landing 

gear extension and retraction, and 

spoiler extension and retraction, along 

with probable failures resulting in 

asymmetric thrust, would also have to 

result in safe, controllable, and 

predictable characteristics. 

Proposed § 23.200(a) and (b) would 

capture the safety intent of §§ 23.143, 

Controllability and Maneuverability— 

General; 23.145, Longitudinal control; 

23.147, Directional and lateral control; 

23.149, Minimum control speed; 23.151, 

Acrobatic maneuvers; 23.153, Control 

during landings; 23.155, Elevator 

control force in maneuvers; and 23.157, 

Rate of roll. The FAA proposes limiting 

the requirements for practical loadings 

and operating altitudes without the use 

of exceptional piloting skill, alertness, 

or strength. 

Current part 23 provides prescriptive 

and detailed test requirements based on 

specific airplane configurations. 

Additionally, the current rules include 

flight test procedures that are based on 

traditional reversible controls and 

engine locations that are, in some cases, 

derived from airplanes designed in the 

1930’s. The FAA proposes performancebased requirements that would remain 

applicable to traditionally designed 

airplanes, but allow alternative 

approaches to showing compliance 

based on new configurations, flight 

control systems, engine locations, and 

number of engines. 

Proposed § 23.200(c) would require 

all certification levels 1 and 2 

multiengine airplanes that lack the 

performance to climb after a critical loss 

of thrust to stall before loss of 

directional control. This is a new 

requirement and it targets the high 

number of fatal accidents that occur 

after an engine failure in this class of 

airplane. Light multiengine airplanes 

that lack the performance to climb after 

the critical loss of thrust are especially 

susceptible to this type of accident. The 

Part 23 Reorganization ARC discussed 

and several members proposed that all 

multiengine airplanes have guaranteed 

climb performance after a critical loss of 

thrust. Ultimately, this approach was 

rejected, as it could impose a significant 

cost on the production of training 

airplanes. Furthermore, several 

members pointed out that the safety 

concern was not that the airplane could 

not climb on one engine, but rather that 

the airplane would depart controlled 

flight at low speeds above stall as a 

result of asymmetric thrust. The FAA 

agrees that loss of control caused by 

asymmetric thrust is the critical safety 

issue that should be addressed and the 

FAA believes that the proposed rule 

responds to this concern. 

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The FAA recognizes concerns 

regarding the proposed requirement—if 

the airplane is allowed to stall, the 

asymmetric thrust will still cause the 

airplane to lose directional control and 

likely depart controlled flight. The FAA 

agrees, but believes that pilots are 

typically more aware of their stall 

speeds than minimum control speed, 

especially during turns. Furthermore, 

these airplanes would be required to 

meet the proposed stall warning and 

stall characteristic requirements, which 

the FAA expects would provide 

additional safety margins beyond 

current requirements. Finally, the 

system that provides stall warning could 

also be designed to provide VMC

warning. 

ix. Proposed § 23.205, Trim 

Proposed § 23.205 would require the 

airplane to maintain longitudinal, 

lateral, and directional trim under 

various conditions, depending on the 

airplane’s certification level, without 

allowing residual forces to fatigue or 

distract the pilot during likely 

emergency operations, including a 

critical loss of thrust on multiengine 

airplanes. 

Proposed § 23.205 would capture the 

safety intent of current § 23.161, Trim. 

Section 23.161(a) addresses the safety 

intent while paragraphs (b), (c), (d), and 

(e) provide prescriptive details on how 

to do flight testing for traditionally 

configured airplanes and are more 

appropriate for inclusion in means of 

compliance. 

x. Proposed § 23.210, Stability 

Proposed § 23.210 would require 

airplanes not certified for aerobatics to 

have static and dynamic longitudinal, 

lateral, and directional stability in 

normal operations, and provide stable 

control force feedback throughout the 

operating envelope. Proposed § 23.210 

would also preclude any airplane from 

exhibiting any divergent stability 

characteristic so unstable as to increase 

the pilot’s workload or otherwise 

endanger the airplane and its occupants. 

Proposed § 23.210 would capture the 

safety intent of the current §§ 23.171, 

Stability—General; 23.173, Static 

longitudinal stability; 23.175, 

demonstration of static longitudinal 

stability; 23.177, Static directional and 

lateral stability; 23.179, Instrumented 

stick force measurements; and 23.181, 

Dynamic stability. The current 

requirements have their origins in 

Aeronautics Bulletin 7, amendment 7a, 

effective October 1, 1934, which 

predates CAR 3. These airplane 

handling quality and stability 

requirements were based on the 

technology associated with simple 

mechanical control systems and what 

was considered acceptable on existing 

airplanes of the time. Although many of 

these requirements are still appropriate 

for traditional flight control systems, 

they do not take into account the 

capabilities of new computer-based 

flight control systems. The FAA 

recognizes the availability of hybrid 

reversible and automated flight control 

systems and proposes performancebased language that would allow their 

installation in part 23 certificated 

airplanes without the use of special 

conditions, while still maintaining 

adequate requirements for reversible 

controls. The intent is to facilitate the 

use of systems that may enhance safety 

while reducing pilot workload. 

xi. Proposed § 23.215, Stall 

Characteristics, Stall Warning, and 

Spins 

Proposed § 23.215 would require an 

airplane to have controllable stall 

characteristics in straight flight, turning 

flight, and accelerated turning flight 

with a clear and distinctive stall 

warning that would provide sufficient 

margin to prevent inadvertent stalling. 

Proposed § 23.215 would allow for 

alternative approaches to meeting this 

requirement for certification levels 1 

and 2 airplanes and certification level 3 

single-engine airplanes, not certified for 

aerobatics, in order to avoid a tendency 

to inadvertently depart controlled flight. 

Proposed § 23.215 would require 

airplanes certified for aerobatics to have 

controllable stall characteristics and the 

ability to recover within one and onehalf additional turns after initiation of 

the first control action from any point in 

a spin. Additionally, the airplane would 

not be allowed to exceed six turns or 

any greater number of turns for which 

certification is requested while 

remaining within the operating 

limitations of the airplane. Proposed 

§ 23.215 would preclude airplanes 

certified for aerobatics from having spin 

characteristics that would result in 

unrecoverable spins due to pilot 

disorientation or incapacitation or any 

use of the flight or engine power 

controls. 

Proposed § 23.215 would capture the 

safety intent of current §§ 23.201, Wings 

level stall; 23.203, Turning flight and 

accelerated turning stalls; 23.207, Stall 

warning; and 23.221, Spinning. 

Historically, the FAA focused its 

requirements on the ability of the 

airplane to recover from a one-turn or 

three-second spin more than on the stall 

characteristics of the airplane. From the 

first fatal stall accident in the Wright 

Flyer airplane to today’s fatal stall 

accidents, the number one cause in 

small airplanes is a departure from 

controlled flight following an 

inadvertent stall. 

Except for accidental departures from 

controlled flight during stall training, 

most of these inadvertent departures 

occur in close proximity to the ground, 

and because of this, the current 

requirement to recover from a one-turn 

or three-second spin may not be the best 

method to assess the safety of the 

airplane. Even an experienced pilot may 

not have enough altitude to recover 

from the spin before impacting the 

ground. For this reason, the FAA 

proposes to delete the one-turn/threesecond spin recovery requirement for 

normal category airplanes. Instead, the 

FAA proposes to increase the stall 

characteristics requirements by 

requiring that all certification levels 1 

and 2 airplanes and certification level 3 

single-engine airplanes provide 

substantial departure resistance to 

prevent inadvertent stalls from resulting 

in a departure from controlled flight and 

becoming fatal accidents. 

Accident studies show that even 

hitting the ground as a result of a stall 

can be survivable if the airplane is still 

in controlled flight. Conversely, 

impacting the ground out of control is 

typically fatal. The FAA envisions 

numerous alternative approaches to 

meeting the proposed requirements, 

ranging from one extreme of spin 

resistance to the other extreme of a total 

systems-based approach such as stick 

pusher. Furthermore, there are envelope 

protection systems and stall warning 

concepts that could also be considered 

when assessing departure resistance. 

The possible approaches to meeting the 

proposed requirements are so broad that 

these alternatives would be better 

addressed in means of compliance. This 

level of protection may vary based on 

the characteristics of the airplane, but 

the FAA expects this change in design 

philosophy would increase the level of 

protection designed into airplanes 

under this proposed rule. Certification 

level 3 multiengine airplanes and 

certification level 4 airplanes 

historically have not had a large number 

of departure-related accidents. While 

the FAA encourages manufacturers to 

consider designing departure resistance 

into these airplanes, the FAA does not 

propose adding a new requirement for 

certification level 3 multiengine 

airplanes and certification level 4 

airplanes. 

The FAA also proposes revising stall 

warning requirements by removing 

prescriptive speed based stall warning 

requirements and requiring a clear and 

distinctive warning with sufficient 

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warning margin for the pilot to prevent 

a stall. Historically, stall warning 

systems in part 23 airplanes have been 

simple, mechanical vanes that may or 

may not provide reasonable lead-time to 

prevent a stall. These systems also can 

provide false alerts when they are not 

needed, creating a nuisance. 

Furthermore, similar sounding warning 

horns that alert the pilot of other 

situations can result in the pilot either 

becoming used to the warning sounds or 

mistaking the stall warning for another 

warning such as the autopilot 

disconnect horn. The FAA believes 

removing the current prescriptive speed 

based stall warning from the rules 

would encourage the installation of 

better, more effective low speed 

awareness systems that may use angle of 

attack, a speed decay rate, or clear voice 

commands to alert the pilot. 

xii. Proposed § 23.220, Ground and 

Water Handling Characteristics 

Proposed § 23.220 would require 

airplanes intended for operation on land 

or water to have controllable 

longitudinal, and directional handling 

characteristics during taxi, takeoff, and 

landing operations. Proposed § 23.220 

would also require an applicant to 

establish a maximum wave height 

shown to provide for controllable 

longitudinal, and directional handling 

characteristics and any necessary water 

handling procedures for those airplanes 

intended for operation on water. 

Proposed § 23.220 would capture the 

safety intent of §§ 23.231, Longitudinal 

stability and control; 23.233, Directional 

stability and control; 23.235, Operation 

on unpaved surfaces; 23.237, Operation 

on water; and 23.239, Spray 

characteristics. 

xiii. Proposed § 23.225, Vibration, 

Buffeting, and High-Speed 

Characteristics 

Proposed § 23.225 would preclude 

vibration and buffeting from interfering 

with the control of the airplane or 

causing fatigue to the flightcrew, for 

operations up to VD/MD. Proposed 

§ 23.225 would allow stall warning 

buffet within these limits. Proposed 

§ 23.225 would preclude perceptible 

buffeting in cruise configuration at 1g 

and at any speed up to VMO/MMO, 

except stall buffeting for high-speed 

airplanes and all airplanes with a 

maximum operating altitude greater 

than 25,000 feet (7,620 meters) pressure 

altitude. Proposed § 23.225 would 

require an applicant seeking 

certification of a high-speed airplane to 

determine the positive maneuvering 

load factors at which the onset of 

perceptible buffet occurs in the cruise 

configuration within the operational 

envelope and preclude likely 

inadvertent excursions beyond this 

boundary from resulting in structural 

damage. Proposed § 23.225 would also 

require high-speed airplanes to have 

recovery characteristics that do not 

result in structural damage or loss of 

control, beginning at any likely speed 

up to VMO/MMO, following an 

inadvertent speed increase and a highspeed trim upset. 

Proposed § 23.225 would capture the 

safety intent of current §§ 23.251, 

Vibration and buffeting; 23.253, High 

speed characteristics; and 23.255, Out of 

trim characteristics. Proposed 

§ 23.225(a), (b), and (c) would capture 

the safety of current § 23.251(a), (b), and 

(c). The current safety intent of 

§§ 23.253 and 23.255 are incorporated 

in proposed § 23.225(d). 

Proposed § 23.225(d)(1) addresses the 

current language in § 23.253, which 

indirectly divides the airplanes by 

engine type rather than performance. 

These requirements have typically been 

applied automatically to turbinepowered airplanes with the assumption 

that all turbine-powered airplanes flew 

fast and high. Piston or electric 

airplanes were not required to meet 

these requirements even if they were 

faster than many turboprops, because of 

propulsion assumptions in the past. For 

this reason, the FAA is amending this 

requirement to be based on performance 

instead of propulsion type using the 

same high-speed criteria from other 

subpart B sections. The existing details 

would be removed from the rules, as 

they are more appropriate as means of 

compliance because it would allow for 

alternatives for non-traditional 

airplanes, such as very fast piston 

airplanes. 

Proposed § 23.225(d)(2) would 

address the current safety intent in 

§ 23.255 by relying on performance and 

design characteristics without 

discriminating based on propulsion 

type. The specific design details are 

more appropriate as means of 

compliance. 

xiv. Proposed § 23.230, Performance and 

Flight Characteristics Requirements for 

Flight in Icing Conditions 

Proposed § 23.230 would require an 

applicant requesting certification for 

flight in icing conditions to demonstrate 

compliance with each requirement of 

this subpart. Exceptions to this rule 

would be those applicable to spins and 

any requirement that would have to be 

demonstrated at speeds in excess of 250 

KCAS, VMO or MMO, or a speed that an 

applicant demonstrates the airframe 

would be free of ice accretion. Proposed 

§ 23.230 would require the stall warning 

for flight in icing conditions and nonicing conditions to be the same. 

Proposed § 23.230 would require an 

applicant requesting certification for 

flight in icing conditions to provide a 

means to detect any icing conditions for 

which certification is not requested and 

demonstrate the airplane’s ability to 

avoid or exit those conditions. Proposed 

§ 23.230 would also require an applicant 

to develop an operating limitation to 

prohibit intentional flight, including 

takeoff and landing, into icing 

conditions for which the airplane is not 

certified to operate. Proposed § 23.230 

would also increase safety by adding 

optional icing conditions a 

manufacturer may demonstrate its 

airplane can either safely operate in, 

detect and safely exit, or avoid. 

Proposed § 23.230 would only apply to 

applicants seeking certification for flight 

in icing. 

Proposed § 23.230 would capture the 

safety intent of the performance and 

flight characteristics requirements in 

current § 23.1419(a) and along with 

proposed §§ 23.940, Powerplant ice 

protection, and 23.1405, Flight in icing 

conditions, and their respective means 

of compliance would address NTSB 

safety recommendations A–96–54 and 

A–96–56. Section 23.1419 specifies that 

airplanes must be able to operate safely 

in the icing conditions identified in 

appendix C to part 25, which 

encompass cloud size drops of less than 

100 microns in diameter. Freezing 

drizzle (i.e., drops up to 500 microns in 

diameter) and freezing rain (i.e., drops 

greater than 500 microns in diameter) 

icing conditions, which can result in ice 

accretion aft of leading edge ice 

protection systems, are not included in 

appendix C to part 25. Amendment 25– 

140 (79 FR 65507, November 4, 2014) 

added these icing conditions to 

appendix O to part 25 and are not being 

defined in proposed § 23.230. The FAA 

believes that the definitions of these 

optional icing conditions would be 

more appropriate as a means of 

compliance. The standards for ‘‘capable 

of operating safely’’ in these conditions 

would be the same as cloud icing with 

additional icing conditions in the 

takeoff phase. 

If certification for flight in the 

optional freezing drizzle or freezing rain 

conditions is not sought, proposed 

§ 23.230 would require these conditions 

be avoided or detected and exited 

safely. The means of compliance for the 

latter, detect and exit the situation, 

would be similar to current guidance in 

AC 23.1419–2D, Certification of Part 23 

Airplanes for Flight in Icing Conditions, 

and is currently applied during part 23 

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airplane icing certifications. These 

criteria are not as extensive as 

recommended by the Part 23 Icing ARC, 

but the FAA did not want to impose an 

additional burden on industry because 

the service history of airplanes certified 

under part 23 and the latest icing 

regulations at amendment 23–43 (58 FR 

18958, April 9, 1993) show no SLD 

related accidents. The FAA believes the 

safety of the existing fleet can be greatly 

increased by improving the freezing 

drizzle and freezing rain capability of 

automated surface weather observation 

systems and pilot education and 

training of the limits of icing 

certification. 

Proposed § 23.230(b) would provide 

an option to avoid, in lieu of detecting 

and exiting, the freezing drizzle or 

freezing rain icing conditions for which 

the airplane is not certified. This option 

is not in current guidance and such 

technology currently does not exist. The 

rule would provide an option in the 

event the technology is developed. The 

FAA believes avoiding rather than 

detecting and exiting would provide for 

safer airplane operations and reduce 

certification costs. 

Proposed § 23.230(c) would require an 

AFM limitation to prohibit flight in 

icing conditions for which the airplane 

is not certified. This reflects current 

guidance in AC 23.1419–2D, which 

most manufacturers of new part 23 icing 

certified airplanes follow today. A 

minority of new manufacturers are not 

using AC 23.1419–2D guidance and 

have inserted AFM limitation language 

that reflects Airworthiness Directives 

(AD) that were issued globally to 

pneumatic boot-equipped airplanes 

between 1996 and 1998. The ADs in the 

below table require immediate exit from 

severe icing and warn that freezing 

drizzle and freezing rain may be 

conducive to severe icing. The proposed 

new limitation is intended to prohibit 

flight in known icing conditions, not 

forecast conditions. 

Airplane model Docket Final rule 

Aerostar Aircraft Corporation Models PA–60–600, PA–60–601, PA–60–601P, PA–60–602P, and PA–60–700P 

Airplanes .............................................................................................................................................................. 97–CE–56–AD 98–04–23 

Pilatus Britten-Norman Ltd., Models BN–2A, BN–2B, and BN–2T Airplanes ......................................................... 97–CE–54–AD 98–04–21 

Pilatus Aircraft Ltd., Models PC–12 and PC–12/45 Airplanes ................................................................................ 97–CE–53–AD 98–20–28 

Partenavia Costruzioni Aeronauticas, S.p.A. Model P68, AP68TP 300, AP68TP 600 Airplanes .......................... 97–CE–51–AD 98–04–20 

Mitsubishi Heavy Industries, Ltd., MU–2B Series Airplanes ................................................................................... 96–CE–61–AD 96–25–02 

Harbin Aircraft Manufacturing Corp., Model Y12 IV airplanes ................................................................................ 97–CE–50–AD 98–04–19 

Empresa Brasileira de Aeronautica S.A. Airplanes. (Embraer) Models EMB–110P1 and EMB–110P2 Airplanes 96–CE–02–AD 96–09–12 

Dornier Luftfahrt GmbH, 228 Series Airplanes ....................................................................................................... 96–CE–04–AD 96–09–14 

De Havilland, Inc., DHC–6 Series Airplanes ........................................................................................................... 96–CE–01–AD 96–09–11 

The Cessna Aircraft Company, 208 Series ............................................................................................................. 96–CE–05–AD 96–09–15 

The Cessna Aircraft Company, Model T210R airplane .......................................................................................... 98–CE–19–AD 98–20–33 

The Cessna Aircraft Company, Models T210, P210, P210R airplanes ................................................................. 97–CE–62–AD 98–05–14 R1 

The Cessna Aircraft Company Models T303, 310R, T310R, 335, 340A, 402B, 402C, 404, F406, 414, 414A, 

421B, 421C, 425, and 441 Airplanes .................................................................................................................. 97–CE–63–AD 98–04–28 

Jetstream Aircraft Limited Models 3101 and 3201 Airplanes ................................................................................. 96–CE–07–AD 96–09–17 

The New Piper Aircraft PA–23, PA–30, PA–31, PA–34, PA–39, PA–40, and PA–42 Series Airplanes ............... 98–CE–77–AD 99–14–01 

The New Piper Aircraft Corporation Models PA–46–310P and PA–46–350P Airplanes ....................................... 97–CE–60–AD 98–04–26 

Beech Aircraft Corporation Models 99, 99A, A99A, B99, C99, B200, B200C, 1900, 1900C, and 1900D Airplanes ................................................................................................................................................................... 96–CE–03–AD 96–09–13 

Raytheon Aircraft Company 200 Series Airplanes .................................................................................................. 98–CE–17–AD 98–20–38 

Raytheon Aircraft Company Models E55, E55A, 58, 58A, 58P, 58PA, 58TC, 58TCA Airplanes, and 60, 65– 

B80, 65–B90, 90, F90, 100, 300, and B300 Series Airplanes ............................................................................ 97–CE–58–AD 98–04–24 

Raytheon Aircraft Company Model 2000 Airplanes ................................................................................................ 97–CE–59–AD 98–04–25 

AeroSpace Technologies Of Australia Pty Ltd., Models N22B and N24A ............................................................. 97–CE–49–AD 98–04–18 

SIAI Marchetti, S.r.1 Models SF600 and SF600A Airplanes .................................................................................. 97–CE–64–AD 98–05–15 

SOCATA—Groupe AEROSPATIALE, Model TBM 700 Airplanes .......................................................................... 97–CE–55–AD 98–04–22 

Twin Commander Aircraft Corporation Models 500, 500–A, 500–B, 500–S, 500–U, 520, 560, 560–A, 560–E, 

560–F, 680, 680–E, 680FL(P), 680T, 680V, 680W, 681, 685, 690, 690A, 690B, 690C, 690D, 695, 695A, 

695B, and 720 Airplanes ..................................................................................................................................... 97–CE–57–AD 98–20–34 

Fairchild Aircraft Corporation, SA226 and SA227 Series Airplanes ....................................................................... 96–CE–06–AD 96–09–16 

Recently, manufacturers of airplanes 

certificated under part 23 have proposed 

inhibiting, or optimizing, bleed air ice 

protection systems above an altitude of 

30,000 feet (9,144 meters) because the 

icing conditions defined in the 

appendix C to part 25 are limited to 

below this altitude. The FAA believes 

ice protection design at high altitude 

should be addressed as a means of 

compliance and not in the proposed 

rule due to various acceptable design 

solutions. An industry means of 

compliance would negate the need for a 

special condition or means of 

compliance issue paper currently 

required for these projects. 

xv. Current Subpart B Regulations 

Relocated to Other Proposed Subparts 

The FAA proposes addressing the 

safety intent of § 23.33, Propeller speed 

and pitch limits, in § 23.900(a) of the 

propulsion rules. Additionally, the first 

part of the current § 23.251(a) that 

addresses structural damage has been 

relocated and is now addressed under 

‘‘flutter’’ in proposed subpart C to part 

23. 

The FAA proposes adopting the Part 

23 Icing and Part 23 Reorganization 

ARC’s recommendations to move 

performance and flight characteristics 

requirements in icing, currently in 

§ 23.1419, to subpart B, so that proposed 

§ 23.1405 only contains systems 

requirements. Proposed § 23.230(a) 

would also include stall warning 

requirements. Current guidance 

contains these stall warning 

recommendations (i.e., margin and type 

of stall) and service history shows them 

to be necessary for safe flight in icing 

conditions. The exceptions for spin and 

high-speed requirements are consistent 

with the current rule and industry 

practice that have shown to provide an 

adequate level of safety in icing 

conditions. The FAA determined that 

the evaluations of ice contaminated 

tailplane stall susceptibility, lateral 

control in icing, and autopilot operation 

in icing, which are included in current 

guidance for part 23 icing certification, 

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are more appropriately addressed as a 

means of compliance. 

xvi. Removal of Subpart B Current 

Regulations 

The FAA proposes removing 

§ 23.45(g) that requires takeoff and 

landing distances be determined on a 

smooth, dry, hard-surfaced runway. The 

FAA believes that most performance 

tests would be done on smooth, dry, 

hard-surfaced runways because these 

surfaces provide applicants with the 

best results. Performance 

determinations on surfaces other than 

smooth, dry hard surfaces would 

provide conservative results and be 

acceptable as long as the surface was 

specified in the AFM. Therefore, the 

FAA believes retaining this requirement 

is unnecessary. 

The FAA proposes removing § 23.63, 

Climb: General, which addresses the 

general climb requirements, because the 

safety intent contained in this section is 

redundant with the safety intent 

proposed in § 23.125 and the testing 

procedures contained in § 23.63 are 

more appropriate for inclusion in means 

of compliance. 

The FAA proposes removing current 

§ 23.221(a) and (b), which address 

spinning requirements for normal and 

utility category airplanes, and would no 

longer be necessary. The increased focus 

on preventing stall-based departures 

along with improved stall margin 

awareness would provide a level of 

safety higher than would be achieved 

through spin testing. 

The FAA proposes removing the 

reference to appendix C to part 25, part 

II, currently in § 23.1419, Ice protection, 

paragraph (a), when relocating § 23.1419 

to proposed § 23.230 and 23.1405. Part 

II is a means of compliance for 

determining critical ice accretions on 

transport category airplanes and is not 

applicable to airplanes certified under 

part 23. 

3. Subpart C—Structures 

a. General Discussion 

The FAA’s intent in proposed subpart 

C is to provide a regulatory framework 

that maintains the current level of safety 

while (1) allowing for certification of 

unique airplane configurations with 

new technology and materials, and (2) 

supporting new means of compliance, 

testing, and analysis. To support new 

technologies, the FAA proposes to 

incorporate the safety intent of recent 

special conditions for airplanes 

equipped with systems that affect 

structural performance, such as load 

alleviation systems, in proposed 

§ 23.305. To support new means of 

compliance, the FAA proposes in 

§ 23.600 to emphasize a holistic 

approach to occupant safety, which 

would allow certain applicants to omit 

current required dynamic seat testing. 

It is not the FAA’s intent to reduce the 

level of safety in the proposed subpart 

C. The FAA based the prescriptive 

requirements in current subparts C and 

D on service history, historic test data, 

and lessons learned. These requirements 

have provided a level of safety where 

structural failure is rare and most often 

attributable to airplane upset or pilot 

disorientation in instrument 

meteorological conditions. A means of 

compliance to proposed subpart C must 

maintain the level of safety provided by 

the current regulations. Applicants 

would need to substantiate the level of 

safety for proposed means of 

compliance that deviate from the 

prescriptive regulations. 

Proposed subpart C would replace 

current subpart C and include those 

sections of current subpart D that are 

applicable to the airframe. We have 

arranged proposed subpart C into the 

following five topics: 

• General: Including § 23.300, Structural 

design envelope; and § 23.305 Interaction of 

systems and structures. 

• Structural Loads: Including § 23.310, 

Structural design loads; § 23.315, Flight load 

conditions; § 23.320, Ground and water load 

conditions; § 23.325, Component loading 

conditions; and § 23.330, Limit and ultimate 

loads. 

• Structural performance: Including 

§ 23.400, Structural strength; § 23.405, 

Structural durability; and § 23.410, 

Aeroelasticity. 

• Design: Including § 23.500, Structural 

design; § 23.505, Protection of structure; 

§ 23.510, Materials and processes; and 

§ 23.515, Special factors of safety. 

• Structural occupant protection: Included 

in § 23.600, Emergency conditions. 

The FAA proposes removing the 

content of current appendix A to part 

23, Simplified design load criteria; 

appendix C to part 23, Basic landing 

conditions; appendix D to part 23, 

Wheel spin-up and spring-back loads; 

and appendix I to part 23, Seaplane 

loads. The content of these current part 

23 appendices is more appropriate for 

inclusion in means of compliance. The 

FAA also proposes removing appendix 

B to part 23, Reserved, since the content 

of this appendix was removed at 

amendment 23–42 (56 FR 344, January 

3, 1991). Refer to appendix 1 of this 

preamble for a cross-reference table 

detailing how the current regulations 

are addressed in the proposed part 23 

regulations. 

b. Specific Discussion of Changes 

i. Proposed § 23.300, Structural Design 

Envelope 

Proposed § 23.300 would require an 

applicant to determine the structural 

design envelope, which describes the 

range and limits of airplane design and 

operational parameters for which an 

applicant would show compliance with 

the requirements of this subpart. 

Proposed § 23.300 would capture the 

safety intent of current §§ 23.321, 

Loads—General, paragraphs (b) and (c); 

23.333, Flight envelope, paragraphs (a), 

(b), and (d); 23.335, Design airspeeds; 

23.337, Limit maneuvering load factors, 

paragraphs (a) and (b); and 23.343, 

Design fuel loads, paragraphs (a) and 

(b). 

Proposed § 23.300 would require the 

applicant to determine and document 

the range of airplane and operational 

parameters for which the applicant will 

show compliance with the requirements 

of subpart C. These parameters would 

include the design airspeeds and 

maneuver load factors often depicted as 

a V-n diagram. An applicant would be 

required to determine design airspeeds, 

including the design maneuvering speed 

(VA), the design cruising speed (VC), the 

design dive speed (VD), design flap and 

landing gear speeds, and any other 

speed used as a design limitation. For 

certification of level 4 airplanes, an 

applicant would be required to 

determine a rough air penetration speed, 

VB. 

Additionally, applicants would have 

to determine the design maneuver load 

factors based on the intended usage of 

the airplane and the values associated 

with the level of safety experienced 

with current designs. Applicants have 

rarely used the relief for maneuvering 

load factors based on airplane 

capabilities in current § 23.337(c). The 

FAA views this relief as an application 

of physical principles, and believes that 

this current requirement does not need 

to be addressed in proposed § 23.300. 

Design weights and inertia parameters 

are also part of the structural design 

envelope. Design weights include the 

empty weight, maximum weight, takeoff 

and landing weight, and maximum zero 

fuel weight. The range of center of 

gravity locations at these and other 

weights is depicted as the weight center 

of gravity envelope. An applicant would 

have to determine the weight and center 

of gravity of occupants, payload, and 

fuel as well as any mass moments of 

inertia required for loads or flutter 

analysis. An applicant would also have 

to specify any other parameters that 

describe the structural design envelope. 

These parameters include maximum 

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sc 

altitude limitations, Mach number 

limitations, and control surface 

deflections. 

ii. Proposed § 23.305, Interaction of 

Systems and Structures 

Proposed § 23.305 would provide a 

regulatory framework for the evaluation 

of systems intended to modify an 

airplane’s structural design envelope or 

structural performance and other 

systems whose normal operating state or 

failed states may affect structural 

performance. Compliance with 

proposed § 23.305 would provide 

acceptable mitigation of structural 

hazards identified in the functional 

hazard assessments required by 

proposed § 23.1315. 

Proposed § 23.305 would apply to 

airplanes equipped with— 

• Structural systems, including load 

alleviation systems, where the intended 

function is to modify structural 

performance, to alleviate the impact of 

subpart C requirements, or provide a 

means of compliance to subpart C 

requirements; and 

• Systems where the intended 

function is non-structural, but whose 

normal operation or failure states affect 

the structural design envelope or 

structural performance, and would 

include fuel management systems, 

flight-envelope protection systems, and 

active control systems. 

Under the current regulations, an 

applicant seeking certification of 

airplanes incorporating structural and 

non-structural systems must ensure that 

failures of these systems will not result 

in exceeding the structural design 

envelope or the structural design loads, 

or other structural performance 

characteristics. An applicant has the 

option of designing the structure to the 

full subpart C and subpart D 

requirements, including margins of 

safety, with the system in its failed state. 

This option may result in increased 

structural weight and reduced airplane 

performance and utility. 

Proposed § 23.1315 in subpart F 

would apply to both structural and nonstructural systems. Guidance material 

for current § 23.1309, the corresponding 

regulation to proposed § 23.1315, allows 

for different acceptable values for 

likelihood of failures based on the 

severity of the hazard, airplane weight, 

and method of propulsion. These 

different values encourage the 

incorporation of equipment that 

improves pilot situational awareness 

and other systems that promote the 

overall airplane level of safety. 

In most cases, means of compliance 

with proposed § 23.305 would follow an 

approach somewhat similar to that used 

in the guidance material for current 

§ 23.1309. Structural failures resulting 

in fatalities are rare, occurring at a rate 

of approximately 3 × 10¥8 per flight 

hour for small airplanes. The reason for 

incorporating structural systems is not, 

in general, to improve safety, but rather 

to reduce structural weight and thereby 

improve airplane performance. 

Proposed § 23.305 would require that 

the level of safety must be the same for 

airplanes equipped with systems that 

affect the structure and airplanes 

without such systems. 

An existing acceptable means of 

complying with proposed § 23.305 is 

provided in several existing special 

conditions that address the interaction 

of systems and structures, for example, 

FAA Special Condition 25–390–SC.20

Most of these special conditions address 

load alleviation systems. Load 

alleviation systems counteract the 

effects of gust and maneuver loads and 

allow an applicant to design a lighter 

structure, thereby improving the 

performance and utility of the airplane. 

These special conditions require that an 

applicant design the structure to the 

required structural safety margins with 

the load alleviation system its normal 

functioning state. The special 

conditions provide a means for an 

applicant to maintain the required 

structural safety margins with the 

system in its failed state by adjusting the 

required safety margins based on the 

likelihood of system failure. Systems 

that fail frequently require higher safety 

margins than systems that rarely fail in 

order to maintain the same level of 

safety. The means of compliance 

described in these special conditions 

allow an applicant to utilize the benefits 

of structural systems and potentially 

eliminate weight and performance 

penalties associated with structural 

hazards due to system failures. 

Applicants who use the means of 

compliance described in the existing 

special conditions would be able to use 

data developed for compliance with 

proposed § 23.1315. This data includes 

identification of failure modes, 

identification of hazards resulting from 

the failure modes, and the likelihood of 

the occurrence of the failure modes. 

With or without the proposed § 23.305 

requirements, an applicant would have 

to account for structural performance 

with the system in its normal operating 

and failed states and evaluate the 

system for compliance to the proposed 

§ 23.1315. The FAA does not expect that 

additional detailed structural analysis 

would be required for compliance with 

proposed § 23.305 other then the 

application of optional lower safety 

margins to the structural performance 

analysis. 

Proposed § 23.305 would allow an 

applicant to realize the value of 

structural and non-structural systems 

and would potentially allow reduced 

structural weight of the airplane. The 

magnitude of the weight reduction 

would depend on the functional 

characteristics of the systems and the 

likelihood of system failures. The FAA 

believes proposed § 23.305 would 

reduce the need for special conditions 

that deal with interaction of systems 

and structures, saving time and effort for 

the FAA and the applicant. 

iii. Proposed § 23.310, Structural Design 

Loads 

Proposed § 23.310 would require an 

applicant to determine structural design 

loads resulting from any externally or 

internally applied pressure, force, or 

moment, which may occur in flight, 

ground and water operations, ground 

and water handling, and while the 

airplane is parked or moored. Proposed 

§ 23.310 would require the applicant to 

determine structural design loads at all 

combinations of parameters on and 

within the boundaries of the structural 

design envelope which result in the 

most severe loading conditions. 

Proposed § 23.310 would also require 

the magnitude and distribution of these 

loads to be based on physical principles 

and would be no less than service 

history has shown can occur within the 

structural design envelope. 

Proposed § 23.310 would capture the 

safety intent of §§ 23.301, Loads; 23.302, 

Canard or tandem wing configurations; 

23.321, Flight Loads—General, 

paragraph (a); and 23.331, Symmetrical 

flight conditions. Proposed § 23.310 

would also capture the intent of several 

current requirements for sound and 

physics-based engineering evaluations. 

An example is in current § 23.301(b), 

which requires that the forces and 

moments applied to the airplane must 

balance in equilibrium, and the 

distribution of loads on the airplane 

must reasonably approximate actual 

conditions. The part 23 regulations 

should not need to prescribe basic 

physical principles, sound engineering 

judgment, and common sense. Proposed 

§ 23.310 would place the burden on the 

applicant to properly account for loads 

acting on the structure. 

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iv. Proposed § 23.315, Flight Load 

Conditions 

Proposed § 23.315 would require an 

applicant to determine the loads 

resulting from vertical and horizontal 

atmospheric gusts, symmetric and 

asymmetric maneuvers, and, for 

multiengine airplanes, failure of the 

powerplant unit which results in the 

most severe structural loads. Proposed 

§ 23.315 would capture the safety intent 

of current §§ 23.333, Flight envelope, 

paragraph (c); 23.341, Gust loads factors; 

23.347, Unsymmetrical flight 

conditions; 23.349, Rolling conditions; 

23.351, Yawing conditions; 23.367, 

Unsymmetrical loads due to engine 

failure; 23.421, Balancing loads; 23.423, 

Maneuvering loads; 23.425, Gust loads; 

23.427, Unsymmetrical loads; 23.441, 

Maneuvering loads; 23.443, Gust loads; 

and 23.445, Outboard fins or winglets, 

paragraphs (b), (c), and (d). 

These current part 23 sections 

establish prescriptive requirements for 

gust loads and symmetrical, rolling, and 

yawing maneuvering loads, acting on 

the wing, horizontal tail, vertical tail, 

and other lifting surfaces. Portions of 

the current sections, such as § 23.331(c), 

are restatements of basic physical 

principles. Proposed § 23.315 would 

remove this language. 

The FAA’s intent is not to lessen the 

structural load requirements. The 

current prescriptive flight load 

requirements have established a level of 

safety where structural failure due to 

overloading is rare. When structural 

failures do occur, the most common 

cause is airplane upset or pilot 

disorientation in instrument 

meteorological conditions. 

The FAA believes the prescriptive 

content of the current regulations, 

including the modified Pratt formula for 

gust loads, the descriptions of 

symmetrical maneuvers, checked and 

unchecked maneuvers, rolling 

maneuvers, and yawing maneuvers are 

more appropriate for inclusion in means 

of compliance. Applicants who wish to 

propose alternate design loading 

conditions should note that extensive 

data collection, testing, and evaluation 

may be necessary to substantiate their 

proposal. 

v. Proposed § 23.320, Ground and Water 

Load Conditions 

Proposed § 23.320 would require an 

applicant to determine the loads 

resulting from taxi, take-off, landing, 

and ground handling conditions 

occurring in normal and adverse 

attitudes and configurations. Proposed 

§ 23.320 would capture the safety intent 

of current §§ 23.471, Ground Loads— 

General; 23.473, Ground load conditions 

and assumptions; 23.477, Landing gear 

arrangement; 23.479, Level landing 

conditions; 23.481, Tail down landing 

conditions; 23.483, One-wheel landing 

conditions; 23.485, Side load 

conditions; 23.493, Braked roll 

conditions; 23.497, Supplementary 

conditions for tail wheels; 23.499, 

Supplementary conditions for nose 

wheels; 23.505, Supplementary 

conditions for skiplanes; 23.507, Jacking 

loads; 23.509, Towing loads; 23.511, 

Ground load; unsymmetrical loads on 

multiple-wheel units; 23.521, Water 

load conditions; 23.523, Design weights 

and center of gravity positions; 23.525, 

Application of loads; 23.527, Hull and 

main float load factors; 23.529 Hull and 

main float landing conditions; 23.531, 

Hull and main float takeoff condition; 

23.533, Hull and main float bottom 

pressures; 23.535, Auxiliary float loads; 

23.537, Seawing loads, and 23.753 Main 

float design. 

The current requirements set forth 

prescriptive requirements for 

determining takeoff and landing loads 

for airplanes operated on land, loads 

acting on floats and hulls for airplanes 

operated on water, as well as ground 

handling loads, including jacking and 

towing conditions. The current 

requirements also provide applicants 

with descriptions of the normal and 

adverse operating conditions and 

configurations for which applicants 

must determine ground and water loads. 

The FAA believes that the 

prescriptive descriptions of the loading 

conditions, normal and adverse 

conditions, and configurations are more 

appropriate for inclusion in means of 

compliance. Applicants who wish to 

propose alternate design loading 

conditions should note that extensive 

data collection, testing, and evaluation 

may be necessary to substantiate their 

proposal. 

vi. Proposed § 23.325, Component 

Loading Conditions 

Proposed § 23.325 would require an 

applicant to determine the loads acting 

on each engine mount, flight control 

and high lift surface, and the loads 

acting on pressurized cabins. Proposed 

§ 23.325 would capture the safety intent 

of current §§ 23.345, High lift devices; 

23.361, Engine torque; 23.363, Side load 

on engine mount; 23.365, Pressurized 

cabin loads; 23.371, Gyroscopic and 

aerodynamic loads; 23.373, Speed 

control devices; 23.391, Control surface 

loads; 23.393, Loads parallel to hinge 

line; 23.395, Control system loads; 

23.397, Limit control forces and torques; 

23.399, Dual control system; 23.405, 

Secondary control system; 23.407, Trim 

tab effects; 23.409, Tabs; 23.415, Ground 

gust conditions; 23.455, Ailerons; and 

23.459, Special devices. 

The current part 23 regulations 

establish prescriptive requirements for 

determining loads acting on pressurized 

cabins, engine mounts and attachment 

structure, control surfaces, high lift 

surfaces, and speed control devices. The 

FAA believes that these prescriptive 

requirements in the current regulations 

are more appropriate for inclusion in 

means of compliance. However, in 

proposed § 23.325, we have retained 

some of the prescriptive requirements 

for pressurized cabins, including 

descriptions of combined loading 

conditions and additional factors of 

safety for determining limit load. 

vii. Proposed § 23.330, Limit and 

Ultimate Loads 

Proposed § 23.330 would describe 

how the applicant must determine the 

limit and ultimate loads associated with 

the structural design loads. Proposed 

§ 23.330 would capture the safety intent 

of current §§ 23.301, Loads, paragraph 

(a); and 23.303, Factor of safety. These 

current sections specify factors of safety 

for determining limit and ultimate 

loads. 

Proposed § 23.330 retains the current 

1.5 safety factor for ultimate loads. This 

safety factor has resulted in a service 

history where structural failures due to 

applied static loads are rare. The FAA 

believes the 1.5 factor of safety is critical 

to maintaining the current level of 

safety. 

Proposed § 23.330 would allow for 

additional special factors of safety to 

account for material and manufacturing 

variability. Proposed § 23.330 would 

also allow alternate factors of safety 

when showing compliance with 

occupant protection loading conditions 

and when showing compliance with 

proposed § 23.305. 

viii. Proposed § 23.400, Structural 

Strength 

Proposed § 23.400 would require an 

applicant to demonstrate that the 

structure will support limit and ultimate 

loads. Proposed § 23.400 would capture 

the safety intent of current §§ 23.305, 

Strength and deformation; and 23.307, 

Proof of structure. 

These current sections provide 

performance criteria for the structure 

when subjected to limit and ultimate 

loads. Proposed § 23.400 would retain 

these performance criteria and would 

require the applicant to demonstrate 

that the structure will meet these 

performance criteria. In this context, 

‘‘demonstrate’’ means the applicant 

must conduct structural tests to show 

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compliance with the structural 

performance requirements, unless the 

applicant shows that a structural 

analysis is reliable and applicable to the 

structure. The FAA proposes not to 

retain the ‘‘3 second’’ rule in proposed 

§ 23.400. This prescriptive requirement 

in current § 23.305(b) requires the 

applicant to demonstrate that the 

structure will support ultimate load for 

at least three seconds. The FAA believes 

this prescriptive requirement is a 

statement of physical principles and 

testing experience and is more 

appropriate for inclusion in means of 

compliance. 

ix. Proposed § 23.405, Structural 

Durability 

Proposed § 23.405 would require an 

applicant to develop and implement 

procedures to prevent structural failures 

due to foreseeable causes of strength 

degradation, and to prevent rapid 

decompression in airplanes with a 

maximum operating altitude above 

41,000 feet. Proposed § 23.405 would 

also require an airplane to be reasonably 

capable of continued safe flight and 

landing with foreseeable structural 

damage caused by high-energy 

fragments from an uncontained engine 

or rotating machinery failure. Proposed 

§ 23.405 would capture the safety intent 

of current §§ 23.365(e), Pressurized 

cabin loads; 23.571, Metallic 

pressurized cabin structures; 23.572, 

Metallic wing, empennage, and 

associated structures; 23.573, Damage 

tolerance and fatigue evaluation of 

structure; 23.574, Metallic damage 

tolerance and fatigue evaluation of 

commuter category airplanes; 23.575, 

Inspections and other procedures; and 

23.627, Fatigue strength. 

Proposed § 23.405(a) would require an 

applicant to develop and implement 

procedures to prevent structural 

failures. These procedures may include 

the safe-life, damage tolerance, or failsafe design approaches described in the 

current regulations. An applicant can 

propose other means of compliance, but 

these means must provide at least the 

same level of safety as current means of 

compliance. Any new means of 

compliance must consider the airplane 

design, manufacturing, operational, and 

maintenance environments. The FAA 

proposes implementing these 

procedures by including them in the 

airplane’s Instructions for Continued 

Airworthiness. 

The procedures must be able to 

prevent structural failures due to 

foreseeable causes of strength 

degradation. Foreseeable causes include 

fatigue and corrosion in metallic 

structures, and fatigue, delaminations, 

disbonds, and impact damage in 

composite structures. New material 

systems or structural designs, such as 

additive manufacturing, may introduce 

new causes of strength degradation and 

may require development of new and 

unique procedures to prevent structural 

failures. 

The current part 23 regulations use 

prevention of catastrophic failures as 

the safety intent of the regulations. The 

word ‘‘catastrophic’’ is used throughout 

the current regulations, current policy, 

and guidance material, especially in 

context of system safety analysis. To 

avoid any potential conflict over the 

meaning of ‘‘catastrophic,’’ proposed 

§ 23.405(a) would specify the 

consequences we want to prevent. 

These consequences include the 

obvious performance criteria for 

prevention of serious injuries, fatalities, 

or hull loss of the airplane. 

The FAA also wants to prevent 

extended periods of operations with 

reduced safety margins in those 

structural components whose failure 

could result in serious injuries, 

fatalities, or hull loss. One situation that 

can result in reduced safety margins is 

fail-safe design. The FAA has identified 

potential shortcomings in fail-safe 

designs, including an applicant’s 

difficulty to anticipate all possible 

failure scenarios and ensure that all 

structural failures would be 

immediately obvious and corrected 

before further flight. The concept of 

failures being obvious and repaired 

before further flight is basic to the 

successful implementation of a fail-safe 

design. This scenario could allow 

operation for extended periods with a 

passive structural failure and reduced 

safety margins. If an applicant chooses 

fail-safe design as a means of 

compliance, an applicant would have to 

ensure that the structure was not 

operating for extended periods with 

reduced safety margins. An applicant 

may be able to apply safe-life or damage 

tolerance principles to ensure that failsafe structure maintains the required 

safety margins without extended 

periods of operation with reduced safety 

margins through life limits or damage 

tolerance based inspections. 

Proposed § 23.405(b) would capture 

the safety intent of current § 23.365(e), 

requiring the applicant to design the 

structure for sudden loss of 

pressurization after the failure of a door 

or window in pressurized 

compartments. Proposed § 23.405(c) 

incorporates the safety intent of current 

§ 23.571(d). Our intention is that the 

damage tolerance methodology would 

remain the accepted means of 

compliance. The FAA views damage 

tolerance as necessary since current 

§ 23.571(d) and proposed § 23.405(c) 

require the applicant to assume that 

structural damage exists in the 

pressurized cabin. However, proposed 

§ 23.405(c) would allow for other means 

of compliance as long as serious injuries 

and fatalities will be prevented. 

Examples of other means of compliance 

might include requiring pilots and 

occupants to use oxygen masks or wear 

pressurized flight suits when operating 

above 41,000 feet (12,497 meters). This 

means of compliance could be 

acceptable in certain airplane designs, 

such as two-seat jet trainers. 

Proposed § 23.405(d) would capture 

the safety intent of current § 23.903(b)(1) 

to minimize hazards to the airframe 

resulting from turbine engine rotorburst. 

The FAA would move the structural 

portion of the rotorburst evaluation from 

current § 23.903(b)(1) to proposed 

§ 23.405(d) to ensure all structural 

requirements are contained in subpart C 

and to avoid potential confusion over 

the structural rotorburst requirements in 

part 23. 

Proposed § 23.405(d) would require 

an applicant to show that the design of 

the structure would provide sufficient 

structural capability to allow continued 

safe flight and landing with foreseeable 

structural damage caused by high 

energy fragments from an uncontained 

engine or rotating machinery failure. 

The FAA recognizes that some highenergy fragment events may result in 

catastrophic failures that may not be 

avoidable and that complete elimination 

of the hazards resulting from high 

energy fragment events may not be 

possible. 

An applicant would be required to 

address other sources of high energy 

rotating machinery fragments in the 

proposed structural rotorburst 

requirements. Our intent is to ensure an 

adequate regulatory framework for 

applications of electrical propulsion 

systems and other unique and novel 

approaches to propulsion, which may 

release high-energy fragments. 

Applicants who have shown 

compliance with current § 23.903(b)(1) 

would be able to show compliance with 

proposed § 23.405(d). Applicants should 

note that previous certification 

programs with turbine engine 

installations have been able to show that 

the airplane structure is capable of 

continued safe flight and landing 

following a rotorburst event. AC 23– 

13A, Fatigue, Fail-Safe, and Damage 

Tolerance Evaluation of Metallic 

Structure for Normal, Utility, Acrobatic, 

and Commuter Category airplanes, 

provides guidance on the required 

structural evaluation. 

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x. Proposed § 23.410, Aeroelasticity 

Proposed § 23.410 would require an 

airplane to be free from flutter, control 

reversal, and divergence at all speeds 

within and sufficiently beyond the 

structural design envelope, for any 

configuration and condition of 

operation, accounting for critical 

degrees of freedom, and any critical 

failures or malfunctions. Proposed 

§ 23.410 would also require an applicant 

to establish tolerances for all quantities 

that affect flutter. 

Proposed § 23.410 would capture the 

safety intent of the current §§ 23.629, 

Flutter; 23.677, Trim systems, paragraph 

(c); and 23.687, Spring devices, in part. 

Specifically, proposed § 23.410 would 

address the safety intent of these rules 

by requiring freedom from flutter, 

control reversal, and divergence, while 

accounting for all speeds, 

configurations, modes, and failures, and 

to establish tolerances on anything 

affecting flutter. The current § 23.629(a) 

states that freedom from flutter, control 

reversal, and divergence must be shown 

by the methods of § 23.629(b) and (c) or 

(d). These paragraphs are prescriptive in 

nature and some portions are applicable 

only to very specific types of designs 

and include speed limitations. 

Therefore, these paragraphs are more 

appropriate as means of compliance. 

The current § 23.629(e) requires the 

evaluation of whirl mode flutter. Since 

this is another flutter mode, it must be 

accounted for when an airplane is 

determined to be free from flutter. The 

current § 23.629(f), (g), (h), and (i) 

provide instructions on how to evaluate 

(1) certain airplane design types, (2) 

designs employing certain methods 

(fail-safe or damage tolerant), or (3) 

airplanes incorporating design 

modifications. The current § 23.677(c) 

requires either that the tab be balanced 

or that the tab controls be irreversible. 

Additionally, it requires that irreversible 

tab systems have adequate rigidity and 

reliability. These are very specific 

design solutions for ensuring freedom 

from flutter. The current § 23.687 

requires that the reliability of spring 

devices used in control systems be 

established by tests unless its failure 

would not cause flutter. This is a 

method of compliance to ensure 

freedom from flutter. All of these 

current requirements are more 

appropriate as means of compliance 

because they describe how to ensure 

freedom from flutter, control reversal, 

and divergence. They are not the safety 

intent, but just one method to achieve 

the safety intent. As such, they serve 

only specific designs utilizing current 

methods, and may or may not be 

adequate for innovative designs or 

accommodate new analytical methods 

or testing techniques. 

xi. Proposed § 23.500, Structural Design 

Proposed § 23.500 would require an 

applicant to design each part, article, 

and assembly for the expected operating 

conditions of the airplane. Proposed 

§ 23.500 would require the design data 

to adequately define the part, article, or 

assembly configuration, its design 

features, and any materials and 

processes used. Proposed § 23.500 

would require an applicant to determine 

the suitability of each design detail and 

part having an important bearing on 

safety in operations. Proposed § 23.500 

would also require the control system to 

be free from— 

• Jamming; 

• Excessive friction, and 

• Excessive deflection when the 

control system and its supporting 

structure are subjected to loads 

corresponding to the limit airloads 

when the primary controls are subjected 

to the lesser of the limit airloads or limit 

pilot forces and when the secondary 

controls are subjected to loads not less 

than those corresponding to maximum 

pilot effort. 

Proposed § 23.500 would capture the 

safety intent of the current §§ 23.601, 

Design and Construction—General; 

23.603, Materials and workmanship, 

paragraph (b); 23.671, Control 

Systems—General, paragraph (a); 

23.683, Operation tests; 23.685, Control 

system details; 23.687, Spring devices, 

in part; and 23.689, Cable systems. 

These current requirements explain 

methods and techniques to ensure an 

adequate design. The proposed rule 

would require an applicant to produce 

an adequate design without specifying 

how. The prescriptive language within 

these current sections noted above, are 

more appropriate for a means of 

compliance. 

xii. Proposed § 23.505, Protection of 

Structure 

Proposed § 23.505 would require an 

applicant to protect each part of the 

airplane, including small parts such as 

fasteners, against deterioration or loss of 

strength due to any cause likely to occur 

in the expected operational 

environment. Proposed § 23.505 would 

require each part of the airplane to have 

adequate provisions for ventilation and 

drainage and would require an 

applicant to incorporate a means into 

the airplane design to allow for required 

maintenance, preventive maintenance, 

and servicing. 

Proposed § 23.505 would capture the 

safety intent of the current §§ 23.607, 

Fasteners; 23.609, Protection of 

structure; and 23.611, Accessibility. 

These current requirements explain 

methods and techniques to ensure an 

adequate design. This proposed rule 

would require the applicant to produce 

an adequate design without specifying 

how to accomplish it. The prescriptive 

language within these current sections 

is more appropriate as a means of 

compliance. 

xiii. Proposed § 23.510, Materials and 

Processes 

Proposed § 23.510 would require an 

applicant to determine the suitability 

and durability of materials used for 

parts, articles, and assemblies, the 

failure of which could prevent 

continued safe flight and landing, while 

accounting for the effects of likely 

environmental conditions expected in 

service. Proposed § 23.510 would 

require the methods and processes of 

fabrication and assembly used to 

produce consistently sound structures 

and, if a fabrication process requires 

close control to reach this objective, an 

applicant would have to perform the 

process under an approved process 

specification. Additionally, proposed 

§ 23.510 would require an applicant to 

justify the selected design values to 

ensure material strength with 

probabilities, account for— 

• The criticality of the structural 

element; and 

• The structural failure due to 

material variability, unless each 

individual item is tested before use to 

determine that the actual strength 

properties of that particular item would 

equal or exceed those used in the 

design, or the design values are 

accepted by the Administrator. 

Proposed § 23.510 would require a 

determination of required material 

strength properties to be based on 

sufficient tests of material meeting 

specifications to establish design values 

on a statistical basis. Proposed § 23.510 

would also require an applicant to 

determine the effects on allowable 

stresses used for design if thermal 

effects were significant on an essential 

component or structure under normal 

operating conditions. 

Proposed § 23.510 would capture the 

safety intent of the current §§ 23.605, 

Fabrication methods and 23.613, 

Material strength properties and design 

values. These current requirements 

explain methods and techniques to 

ensure adequate materials and process 

controls. This proposed rule would 

require the applicant to ensure the 

resulting materials and processes are 

adequate without specifying how. The 

prescriptive language within the current 

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21See www.regulations.gov (Docket #FAA–2015– 

1621). 

sections is more appropriate as a means 

of compliance. 

xiv. Proposed § 23.515, Special Factors 

of Safety 

Proposed § 23.515 would require an 

applicant to determine a special factor 

of safety for any critical design value 

that was uncertain, used for a part, 

article, or assembly likely to deteriorate 

in service before normal replacement, or 

subject to appreciable variability 

because of uncertainties in 

manufacturing processes or inspection 

methods. Proposed § 23.515 would 

require an applicant to determine a 

special factor of safety using quality 

controls and specifications that 

accounted for each structural 

application, inspection method, 

structural test requirement, sampling 

percentage, and process and material 

control. Proposed § 23.515 would 

require an applicant to apply any 

special factor of safety in the design for 

each part of the structure by multiplying 

each limit load and ultimate load by the 

special factor of safety. 

Proposed § 23.515 would capture the 

safety intent of current §§ 23.619, 

Special factors; 23.621, Casting factors; 

23.623, Bearing factors; 23.625, Fitting 

factors; 23.657, Hinges; 23.681(b), Limit 

load static test (in part); and 23.693, 

Joints. These current requirements 

explain methods and techniques to 

ensure adequate special factors are used 

and the proposed rule would simply 

require the applicant to determine and 

apply adequate special factors without 

specifying what these are. The 

prescriptive language within the current 

sections is more appropriate as a means 

of compliance. 

xv. Proposed § 23.600, Emergency 

Conditions 

Proposed § 23.600 would require the 

airplane, even if damaged in emergency 

landing conditions, to provide 

protection to each occupant against 

injury that would preclude egress. 

Proposed § 23.600 would require the 

airplane to have seating and restraints 

for all occupants, consisting of a seat, a 

method to restrain the occupant’s pelvis 

and torso, and a single action restraint 

release, which meets its intended 

function and does not create a hazard 

that could cause a secondary injury to 

an occupant. Proposed § 23.600 would 

require the airplane seating, restraints, 

and cabin interior to account for likely 

flight and emergency landing 

conditions. Additionally, they could not 

prevent occupant egress or interfere 

with the operation of the airplane when 

not in use. 

Proposed § 23.600 would require each 

baggage and cargo compartment be 

designed for its maximum weight of 

contents and for the critical load 

distributions at the maximum load 

factors corresponding to the determined 

flight and ground load conditions. 

Proposed § 23.600 would also require 

each baggage and cargo compartment to 

have a means to prevent the contents of 

the compartment from becoming a 

hazard by impacting occupants or 

shifting, and to protect any controls, 

wiring, lines, equipment, or accessories 

whose damage or failure would affect 

operations. 

Proposed § 23.600 would capture the 

safety intent of current §§ 23.561, 

Emergency Landing Conditions— 

General; 23.562, Emergency landing 

dynamic conditions; 23.785, Seats, 

berths, litters, safety belts, and shoulder 

harnesses; and 23.787, Baggage and 

cargo compartments. The prescriptive 

language within these current sections 

are more appropriate as a means of 

compliance, and thus would allow 

flexibility for new technology to be 

available in new part 23 airplanes in a 

timely manner. 

Occupant safety for aviation has 

progressed incrementally over the years. 

This has resulted in rulemaking that has 

enhanced safety for individual system 

components, but not in an integrated 

fashion. Modeling and analysis 

techniques have matured to a point that 

may allow evaluation of more crash 

scenarios and crashworthiness 

components as an integrated system. 

The FAA has relied on many industry 

studies to develop current occupant 

safety rules. These studies evaluated 

characteristics of actual accidents, fullscale aircraft drop testing, and dynamic 

seat testing on a sled. When dynamic 

seat testing began, determination of an 

adequate generic floor impulse that 

represented a survivable aircraft crash 

was established. As an alternative to 

current crashworthiness requirements, 

the proposed rule would allow for 

evaluation of the conditions of likely 

impacts, assessment of vehicle response, 

and ultimately, evaluation of occupant 

reaction to vehicle impact and vehicle 

response. 

Technology used in aviation 

crashworthiness, in a large part, has 

come from the automotive industry. The 

automotive industry has analyzed 

crashworthiness components as a 

system for many years. The automotive 

industry generally has a more developed 

crashworthiness analysis capability than 

that used in the aviation industry. This 

advanced crashworthiness analysis 

capability has evolved primarily 

because of the— 

• Public expectation for automobile 

safety; 

• Higher general public likelihood 

and exposure to automobile accidents; 

and 

• High automobile production rates 

allow for multiple actual full-vehicle 

crash tests that result in very accurate 

crash impulse data from the outer 

surface of the vehicle all the way to the 

occupant. 

Because of these facts, automotive 

designers know accurate impulses and 

the specific vehicle response for impact 

conditions. Furthermore, this data can 

be extrapolated to consider many more 

accident scenarios. Automotive safety 

requirements progressively add new 

impact scenario requirements and 

enhanced impulse magnitudes, thus 

requiring more industry innovation. 

This innovation has enabled rapid 

advances in automotive occupant 

protection systems. 

Automotive safety begins at the 

outside of the vehicle, evaluating the 

entire system’s response. In contrast, 

aircraft manufacturers have used 

essentially the same generic designed 

pulse imparted at the cabin floor for the 

last 25 years. The same impulse applies 

to all GA airplanes independent of the 

structure below the cabin floor and the 

aircraft’s stall speed, unless the stall 

speed is greater than 61 knots. 

Determining airplane crashworthiness is 

a more complex process than 

determining automotive 

crashworthiness because of higher 

impact speeds, lighter weight structures, 

and the effect of the third dimension of 

altitude on the aircraft. Dynamic seat 

testing has improved crashworthiness in 

aviation; however, the FAA believes 

that newer means of evaluating the full 

aircraft response to crash conditions via 

modeling, newer materials, and new 

technologies promise to offer improved 

features, evaluation, and accuracy that 

would facilitate consideration of more 

crash scenarios and evaluation of more 

variables that could improve 

survivability. 

The NTSB produced a series of 

reports, called the General Aviation 

Crashworthiness Project,21 in the 1980s 

that evaluated over 21,000 GA airplane 

crashes that occurred between 1972 and 

1981. The NTSB evaluated airplane 

orientation, impact magnitudes, and 

survival rates and factors on many of 

these accidents in order to provide 

information to support changes in 

crashworthiness design standards for 

seating and restraint systems in GA 

airplanes. These reports also established 

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22See www.regulations.gov (Docket #FAA–2015– 

1621). 

23See www.regulations.gov (Docket #FAA–2015– 

1621). 

conditions approximating survivable 

accidents, and categorized factors that 

would have the largest impact on safety. 

These reports further illuminated the 

various crashworthiness systems and 

their respective impact to overall safety. 

Amendment 23–36 (53 FR 30802, 

August 15, 1988), to part 23 referenced 

these reports for dynamic seats but did 

not adopt a systems-approach to 

evaluating crashworthiness of an 

airplane design. 

The NTSB reports identified several 

factors that would enhance safety. All of 

these factors working together as a 

system should result in a safer airplane. 

However, the assessment indicated that 

shoulder harnesses offer the fastest 

individual improvement for safety. The 

FAA codified the shoulder harnesses 

requirement in amendments 23–19 (42 

FR 20601, June 16, 1977) and 23–32 (50 

FR 46872, November 13, 1985), for 

newly manufactured airplanes. The 

FAA also issued policy statement ACE– 

00–23.561–01,22 Methods of Approval 

of Retrofit Shoulder Harness 

Installations in Small Airplanes, to 

streamline the process for retrofitting 

older airplanes. 

Survivable volume is another critical 

factor to survival. Survivable volume is 

the ability of the airframe to protect the 

occupants from external intrusion or 

cabin crushing during and after the 

accident sequence. There were several 

observed accidents in the NTSB study 

where conventional aircraft 

construction simply crushed an 

otherwise restrained occupant. 

Crashworthiness regulations have never 

included survivable volume as a factor, 

except for aircraft turnover. Airplane 

designs should provide the space 

needed for the protection and restraint 

of the occupants. A compromised 

survivable volume could cause 

occupant impact with objects in the 

cabin. This is one of the first steps in the 

analysis of airplane crashworthiness. 

Additional data from the NTSB 

General Aviation Crashworthiness 

Project suggested that energy-absorbing 

seats that protect the occupant from 

vertical loads could enhance occupant 

survivability and work to prevent 

serious injury, thereby enhancing odds 

for egress and preventing many 

debilitating long-term injuries. The FAA 

established dynamic seat testing 

requirements in amendment 23–36 for 

airplanes certificated under part 23. 

Energy absorbing seats benefit a smaller 

portion of accident occupants because 

accident impacts with larger vertical 

components tend to reduce occupant 

survival odds. Energy attenuation from 

vertical forces, both static and dynamic, 

has been important to crashworthiness 

regulations within the past 25 years. 

Seat deformation throughout the 

emergency landing sequence is 

acceptable if the load path through 

attachment, seat, and restraint remains 

continuous. Coupling the seat 

performance to the rest of the airframe 

response is important to the 

enhancement and understanding of 

occupant survivability. The FAA 

believes that allowing designers to 

consider a particular airframe’s unique 

deformation in a crash, the designers 

can create a safer cabin for the 

occupants. Using unique airframe 

deformations would result in more 

accurate accident floor impulses and 

may allow evaluation of crash impulses 

in multiple directions; instead of only 

two directions considered in current 

certification. 

Occupant restraints must maintain 

integrity, stay in place on the occupant 

throughout the event, properly 

distribute loads on the occupant, and 

restrain the occupant by mitigating 

interaction with other items in the 

cabin. Restraints originally were 

comprised of lap belts. Shoulder 

harnesses were later required as 

discussed above. Newer technology that 

enhances or supplements the 

performance of restraints, like airbags 

and consideration of items in the cabin 

that the occupant might impact, are now 

being considered for inclusion in 

designs. The use of airbags has greatly 

increased passenger safety in 

automobiles, which offer protection in 

much more severe impacts and in 

impacts from multiple directions, and 

could be a viable option for airplanes as 

well. 

Seat retention in airplanes is a factor 

identified as another basic building 

block for crashworthiness. The NTSB 

reports shows more than a quarter of 

otherwise-survivable accidents included 

instances where the seats broke free at 

the attachment to the airplane, resulting 

in fatalities or serious injuries. Dynamic 

seat testing requirements address the 

ability of seat assemblies to remain 

attached to the floor, even when the 

floor shifts during impact. Pitching and 

yawing of the seat tracks during 

dynamic seat tests demonstrates the 

gimbaling and flexibility of the seat. 

All of the aforementioned safety 

considerations must work together to 

enhance occupant safety and 

survivability. The FAA believes that 

evaluating occupant safety, as a whole 

system, would allow for a better 

understanding of vehicle performance 

in an emergency landing, enabling the 

incorporation of innovative technology. 

The transportation industry has made 

significant progress with energy 

absorbing seats and restraint technology. 

The FAA believes enhanced cabin 

strength that improves survivable 

volume, coupled with better restraint 

technology and refined energy absorbing 

seats, would be key factors in improving 

expansion of the survivable accident 

envelope. These factors and additional 

considerations were included in the 

Small Airplane Crashworthiness Design 

Guide.23 This guide was prepared for 

the Advanced General Aviation 

Transports Experiments and the 

National Aerospace and Space 

Administration and addresses the 

concept of designing crashworthiness 

into an airplane design as a system. 

In order to evaluate an accident from 

an occupant’s perspective, the 

emergency landing condition must first 

be defined, starting with the conditions 

external to the aircraft. In most 

survivable accidents, the pilot is able to 

maintain control of the aircraft prior to 

impact. Accidents where the airplane 

impacts the ground out of control are 

typically much less survivable. Speed 

and impact orientation are significant 

factors in crash survivability. Therefore, 

considerations for impact beyond a 

controllable impact are beyond the 

scope of these proposed regulations. 

The slowest forward speed that any 

fixed wing airplane can fly is its stall 

speed. This stall speed can vary with 

airplane configuration and weight, but 

represents the most universal parameter 

for impact speed and energy attenuation 

at impact. For this reason, stall speed is 

the starting point for consideration of 

expected impact conditions. 

Orientation of impact can vary with 

pitch, yaw, terrain angle, and angle of 

flight path and becomes dynamic as the 

pilot loses control effectiveness at stall. 

The result is the airplane impact angle 

can result in a combination of 

horizontal and vertical loads and 

impulses that vary widely. Angle of 

impact, the line of the center of mass 

with respect to the angle of the impact 

surface, can also affect the amount of 

energy absorbed or transmitted to the 

occupant. 

An accident impulse is a dynamic 

event that rapidly loads and unloads the 

structure. Dynamic impacts accurately 

represent the impact event, often 

including load levels far surpassing the 

static load requirements. Dynamic 

testing is also subject to a wide variation 

of results due to the unpredictable 

dynamic responses of varying 

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construction methods and materials, 

resulting in complicated modeling and 

analysis. This contrasts with static load 

tests that load the structure slowly, 

maintain that load at high levels, are 

generally simpler, and often provide 

adequate demonstration of part strength. 

Static analysis is generally more reliable 

with both testing and modeling; 

however, it does not capture the nature 

of rapid loading. Some combination of 

dynamic and static testing allows for the 

best understanding of airplane behavior 

during an accident. 

Compliance with the proposed rule 

could be shown using conventional 

means of compliance like dynamic 

testing of seats, and static testing of 

other components using the prescriptive 

methods contained in the current part 

23. Alternative compliance methods 

could include analysis or modeling 

supported by testing using an airframe 

coupled with the airplane’s performance 

envelope, viewing the entire interaction 

of ground, airplane, and occupant, thus 

using a more complete systemic 

approach to achieve improved 

protection. 

Proposed § 23.600(a) is intended to 

provide structural performance that 

protects the occupant during an 

emergency landing while accounting for 

only static loads and assuming all safety 

equipment is in use. The proposed 

section would capture the safety intent 

of the current § 23.561. As noted earlier, 

static loads are generally lower than 

peak dynamic loads; however, they may 

offer a more-easily predictable loading 

condition and are generally of longer 

duration such that the structure can 

fully react to the load. The landing 

conditions should consider possible 

accident sequence variables at impact, 

including restraint of items of mass 

within the cabin, directions of loading 

along or about the three axes, and 

airframe response with respect to the 

occupants and effects of airframe 

deflection during an emergency landing. 

Effects of emergency landing on the 

airplane should also be considered to 

include the effect of airframe damage 

and how static loads would affect egress 

and survivable cabin volume. Items of 

mass within the cabin and rear mounted 

engines have also been traditionally 

considered using even higher static 

loads as an additional factor of safety to 

ensure that these items of mass are 

restrained and would be among the last 

items to come free in an accident. 

Proposed § 23.600(b) is intended to 

provide boundary conditions for the 

emergency landing sequence for both 

static and dynamic load considerations. 

The proposed section would capture the 

safety intent of the current §§ 23.561 

and 23.562. The airplane stall speed 

limits the maximum forward impact 

speed. The emergency landing 

condition assumes the pilot maintains 

airplane control at or near final impact, 

thereby limiting impact velocity. 

Proposed § 23.600(c) would capture 

the survivability factors for the occupant 

in the cabin during the emergency 

landing sequence and would capture the 

safety intent of current § 23.562. These 

factors include proper use and loading 

of seats and restraints, and the 

interaction of the occupants with each 

other and the cabin interior. 

Survivability is determined upon the 

occupant’s interaction with the interior, 

seat, and restraints, and bounded by 

established human injury criteria. 

Proposed § 23.600(d) would provide 

the framework for seats and occupant 

restraints and would require simplified 

seat and restraint requirements for all 

occupants. This proposed section would 

capture the safety intent of current 

§ 23.785. 

Proposed § 23.600(e) would establish 

requirements for baggage and cargo 

compartments and the restraint of 

contents. The proposed section would 

capture the safety intent of current 

§ 23.787. 

xvi. Current Subpart C Regulations 

Relocated to Other Proposed Subparts 

As discussed, the FAA proposes 

removing current §§ 23.561, 23.562, 

23.785, and 23.787. Also, this proposal 

would consolidate the safety intent of 

these crashworthiness regulations in 

proposed § 23.600. 

4. Subpart D—Design and Construction 

a. General Discussion 

The FAA proposes restructuring 

current subpart D to retain the 

requirements for flight control systems, 

along with their attachment to the 

structure and landing gear, and 

occupant safety other than structural 

requirements. The FAA proposes to 

align structural requirements, found in 

current §§ 23.601 through 23.659, to 

proposed subpart C. Aspects that 

directly affected the pilot’s interface 

with the airplane, such as the throttle 

shape, would be relocated to proposed 

§ 23.1500, Flightcrew Interface. 

The FAA also proposes, in those 

sections where there are requirements 

specific to the current commuter 

category, to use certification level 4. In 

those sections where there are current 

requirements specific to multiengine 

jets over 6,000 pounds, the FAA 

proposes requirements for certification 

level 3, high-speed multiengine 

airplanes as discussed earlier in this 

proposal. Refer to appendix 1 of this 

preamble for a cross-reference table 

detailing how the current regulations 

are addressed in the proposed part 23 

regulations. 

The subpart D organization was more 

complex than other subparts due to the 

relocation and removal of many 

requirements at the sub-paragraph level. 

To reduce confusion, the specific 

discussion of subpart D changes is 

shown in a cross reference table at the 

end of the specific discussion section 

below rather than the Relocation and 

Removal paragraphs in other subparts. 

b. Specific Discussion of Changes 

i. Proposed § 23.700, Flight Controls 

Systems 

Proposed § 23.700 would require an 

applicant to design airplane flight 

control systems to prevent major, 

hazardous, and catastrophic hazards. 

Proposed § 23.700 would require an 

applicant to design trim systems to 

prevent inadvertent, incorrect, or abrupt 

trim operation. In addition, proposed 

§ 23.700 would require an applicant to 

design trim systems to provide a means 

to indicate— 

• The direction of trim control 

movement relative to airplane motion; 

• The trim position with respect to 

the trim range; 

• The neutral position for lateral and 

directional trim; and 

• For all airplanes except simple 

airplanes, the range for takeoff for all 

applicant requested center of gravity 

ranges and configurations. 

Proposed § 23.700 would also require 

an applicant to design trim systems to 

provide control for continued safe flight 

and landing when any one connecting 

or transmitting element in the primary 

flight control system failed, except for 

simple airplanes. Additionally, 

proposed § 23.700 would require an 

applicant to design trim systems to limit 

the range of travel to allow safe flight 

and landing, if an adjustable stabilizer is 

used. 

Furthermore, proposed § 23.700 

would require the system for an airplane 

equipped with an artificial stall barrier 

system to prevent uncommanded 

control or thrust action and provide for 

a preflight check. The FAA also 

proposes requiring an applicant seeking 

certification of a certification level 3 

high-speed or certification level 4 

airplane to install a takeoff warning 

system on the airplane, unless the 

applicant demonstrates that the 

airplane, for each configuration, could 

takeoff at the limits of its trim and flap 

ranges. 

Proposed § 23.700(b)(3) would also 

allow an exception for simple airplanes 

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from the requirement to provide control 

for continued safe flight and landing 

when any one connecting or 

transmitting element in the primary 

control system fails. This would provide 

a level of safety equivalent to that 

specified in EASA’s CS–VLA. Last, 

proposed § 23.700(d) would maintain 

the level of safety in the current 

requirements for a takeoff warning 

system. 

Proposed § 23.700 would capture the 

safety intent of current §§ 23.677, Trim 

systems, paragraphs (a), (b), and (d); 

23.689, Cable systems, paragraphs (a) 

and (f); 23.691, Artificial stall barrier 

system, paragraphs (a), (b), (d), (e) and 

(f); 23.697, Wing flap controls, 

paragraphs (a); and 23.703, Takeoff 

warning system, paragraphs (a) and (b). 

This proposed section would apply to 

the function, usability, and hazard 

levels of all mechanical, electrical, or 

electronic control systems. The 

certification levels proposed in this 

NPRM would be incorporated into the 

mechanical, electrical, or electronic 

control systems to maintain the 

differences in airplanes certificated 

under part 23 (i.e., weight and 

powerplant.) 

ii. Proposed § 23.705, Landing Gear 

Systems 

Proposed § 23.705 would require an 

airplane’s landing gear and retracting 

mechanism be able to withstand 

operational and flight loads. Proposed 

§ 23.705 would require an airplane with 

retractable landing gear to have a 

positive means to keep the landing gear 

extended and a secondary means for 

extending the landing gear that could 

not be extended using the primary 

means. Proposed § 23.705 would also 

require a means to inform the pilot that 

each landing gear is secured in the 

extended and retracted positions. 

Additionally, proposed § 23.705 would 

require an airplane, except for airplanes 

intended for operation on water, with 

retractable landing gear to also have a 

warning to the pilot if the thrust and 

configuration is selected for landing and 

yet the landing gear is not fully 

extended and locked. 

Furthermore, if the landing gear bayis 

used as the location for equipment other 

than the landing gear, proposed § 23.705 

would require that equipment be 

designed and installed to avoid damage 

from tire burst and from items that may 

enter the landing gear bay. Proposed 

§ 23.705 would also require the design 

of each landing gear wheel, tire, and ski 

account for critical loads and would 

require a reliable means of stopping the 

airplane with kinetic energy absorption 

within the airplane’s design 

specifications for landing. For 

certification level 3 high-speed 

multiengine and certification level 4 

multiengine airplanes, proposed 

§ 23.705 would require the braking 

system to provide kinetic energy 

absorption within the design of the 

airplane specifications for rejected 

takeoff as the current rules do for 

multiengine jets over 6,000 pounds and 

commuter category airplanes. 

Proposed § 23.705 would capture the 

safety intent of current §§ 23.729, 

Landing gear extension and retraction 

system, paragraphs (a), (b), (c), and (e); 

23.731, Wheels; 23.733, Tires, paragraph 

(a); 23.735, Brakes, paragraphs (a), (b), 

and (e); 23.737, Skis. The FAA proposes 

to combine the fixed and retractable 

landing gear systems into the proposed 

section, which would apply to the 

function, usability, and hazard levels of 

all mechanical, electrical, or electronic 

landing gear systems. 

iii. Proposed § 23.710, Buoyancy for 

Seaplanes and Amphibians 

Proposed § 23.710 would require 

airplanes intended for operations on 

water to provide buoyancy of 80 percent 

in excess of the buoyancy required to 

support the maximum weight of the 

airplane in fresh water. Proposed 

§ 23.710 would also require airplanes 

intended for operations on water to have 

sufficient watertight compartments so 

the airplane will stay afloat at rest in 

calm water without capsizing if any two 

compartments of any main float or hull 

are flooded. 

Proposed § 23.710 would capture the 

safety intent of current §§ 23.751(a), 

Main float buoyancy; 23.755, Hulls; and 

23.757, Auxiliary floats. The FAA 

proposes combining the floats or hulls 

landing gear systems into the proposed 

section and having it apply to the 

function, usability, and hazard levels of 

hulls and floats. The existing rule 

requires at least four watertight 

compartments of approximately equal 

volume, which the FAA proposes to 

remove because they are specific design 

requirements and are addressed in the 

proposed performance-based 

requirements. 

To encourage the installation of 

buoyancy systems with new safety 

enhancing technology and streamlining 

the certification process, the FAA 

proposes removing most of the current 

prescriptive requirements and the 

detailed means of compliance for these 

requirements from the current part 23 

and replacing them with performancebased regulations. The FAA expects the 

current means of compliance would 

continue to be used for the traditional 

airplane designs under part 23. 

iv. § 23.750, Means of Egress and 

Emergency Exits 

Proposed § 23.750 would require the 

airplane cabin exit be designed to 

provide for evacuation of the airplane 

within 90 seconds in conditions likely 

to occur, excluding ditching, following 

an emergency landing. For ditching, 

proposed § 23.750 would require the 

cabin exit for all certification levels 3 

and 4 multiengine airplanes be designed 

to allow evacuation in 90 seconds. 

Proposed § 23.750 would require each 

exit to have a simple and obvious 

means, marked inside and outside the 

airplane, to be opened from both inside 

and outside the airplane, when the 

internal locking mechanism is in the 

locked position. 

Proposed § 23.750 would also require 

airplane evacuation paths to protect 

occupants from serious injury from the 

propulsion system, and require that 

doors, canopies, and exits be protected 

from opening inadvertently in flight. 

Proposed § 23.750 would preclude each 

exit from being obstructed by a seat or 

seat back, unless the seat or seat back 

could be easily moved in one action to 

clear the exit. Proposed § 23.750 would 

also require airplanes certified for 

aerobatics to have a means to exit the 

airplane in flight. 

Proposed § 23.750 would capture the 

safety intent of current §§ 23.783, Doors, 

paragraphs (a), (b), (c), and (d); 23.791, 

23.803, Emergency evacuation, 

paragraph (a); 23.805, Flightcrew 

emergency exits; 23.807, Emergency 

exits except paragraphs (a)(3), (b)(1), (c), 

(d)(1) and (d)(4); 23.811, Emergency exit 

marking; 23.812, Emergency lighting; 

23.813, Emergency exit access, 

paragraph (a); and 23.815, Width of 

aisle; and CS–VLA–783, Exits. This 

proposed rule would incorporate the 

requirements for all door and emergency 

exits and remove specified design 

solutions and means of compliances. 

To encourage the installation of egress 

and emergency exits with new safety 

enhancing technology and streamline 

the certification process, the FAA 

proposes removing most of the current 

prescriptive requirements and the 

detailed means of compliance for these 

requirements from the current part 23. 

The FAA expects that the current 

prescriptive means of compliance 

would continue to be used for 

traditional part 23 airplane designs. 

The FAA would continue to accept an 

airplane designed to meet these 

prescriptive design constraints as means 

of compliance to meet the proposed 

performance standard. However, if an 

airplane did not meet the prescriptive 

design constraints, the applicant could 

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propose its own means of compliance to 

show compliance with the proposed 

performance standard. Historically, the 

FAA has accepted an emergency 

evacuation demonstration in less than 

90 seconds as an ELOS for airplanes that 

did not meet the prescriptive design 

requirements in the current part 23 

regulations. AC 20–118A, Emergency 

Evacuation Demonstration, contains an 

acceptable means of compliance for the 

90-second requirement for emergency 

evacuation. 

v. Proposed § 23.755, Occupant Physical 

Environment 

Proposed § 23.755 would require an 

applicant to design the airplane to allow 

clear communication between the 

flightcrew and passengers and provide a 

clear, sufficiently undistorted external 

view to enable the flightcrew to perform 

any maneuvers within the operating 

limitations of the airplane. Proposed 

§ 23.755 would also require an applicant 

to design the airplane to protect the 

pilot from serious injury due to high 

energy rotating failures in systems and 

equipment, and protect the occupants 

from serious injury due to damage to 

windshields, windows, and canopies. 

Additionally, proposed § 23.755 

would require, for certification level 4 

airplanes, each windshield and its 

supporting structure directly in front of 

the pilot to withstand the impact 

equivalent of a two-pound bird at 

maximum approach flap airspeed and 

allow for continued safe flight and 

landing after the loss of vision through 

any one panel. 

Furthermore, proposed § 23.755 

would require any installed oxygen 

system to include a means to determine 

whether oxygen is being delivered and 

a means for the flightcrew to turn on 

and shut off the oxygen supply, and the 

ability for the flightcrew to determine 

the quantity of oxygen available. 

Proposed § 23.755 would also require 

any installed pressurization system to 

include a pressurization system test and 

a warning if an unsafe condition exists. 

Proposed § 23.755 would capture the 

safety intent of current §§ 23.771, Pilot 

compartment, paragraphs (b) and (c); 

23.775, Windshields and windows, 

paragraphs (a), (b), (c), (d), and (h); 

23.831, Ventilation; 23.841, Pressurized 

cabins, paragraphs (a), (b)(6), (c) and (d); 

23.843, Pressurization tests; 23.1441, 

Oxygen equipment and supply, 

paragraphs (c), (d) and (e); 23.1443, 

minimum mass flow of supplemental 

oxygen, paragraphs (a), (b), and (c); 

23.1445; Oxygen distribution system; 

23.1447, Equipment standards for 

oxygen dispensing units, paragraphs (a) 

through (d) and (f); 23.1449, means of 

determining use of oxygen; and 23.1461, 

Equipment containing high energy 

rotors. Current part 23 regulations 

contain prescriptive language and 

means of compliance for the occupant 

physical environment requirements. 

The FAA proposes to remove the 

specific requirements to allow an 

applicant to specify the means of 

compliance for the physical needs of the 

occupants including temperature, 

ventilation, pressurization, 

supplemental oxygen, etc. For example, 

current § 23.831(a) requires carbon 

monoxide not exceeding one part in 

20,000 parts of air. The FAA proposes 

revising this by requiring breathable 

atmosphere without hazardous 

concentrations of gases and vapors. 

vi. Proposed § 23.800, Fire Protection 

Outside Designated Fire Zones 

Proposed § 23.800 would require that 

insulation on electrical wire and 

electrical cable outside designated fire 

zones be self-extinguishing. Proposed 

§ 23.800 would require airplane cockpit 

and cabin materials in certification 

levels 1, 2, and 3 be flame-resistant. 

Proposed § 23.800 would require 

airplane cockpit and cabin materials in 

certification level 4 airplanes be selfextinguishing. Proposed § 23.800 would 

also require that airplane materials in 

the baggage and cargo compartments, 

which are inaccessible in flight and 

outside designated fire zones, be selfextinguishing. Proposed § 23.800 would 

require that any electrical cable 

installation that would overheat in the 

event of circuit overload or fault be 

flame resistant. Additionally, proposed 

§ 23.800 would preclude thermal 

acoustic materials outside designated 

fire zones from being a flame 

propagation hazard. Proposed § 23.800 

would also require sources of heat that 

are capable of igniting adjacent objects 

outside designated fire zones to be 

shielded and insulated to prevent such 

ignition. 

Proposed § 23.800 would require 

airplane baggage and cargo 

compartments, outside designated fire 

zones, to be located where a fire would 

be visible to the pilots, or equipped with 

a fire detection system and warning 

system, and be accessible for the manual 

extinguishing of a fire, have a built-in 

fire extinguishing system, or be 

constructed and sealed to contain any 

fire within the compartment. 

Proposed § 23.800 would require a 

means to extinguish any fire in the 

cabin, outside designated fire zones, 

such that the pilot, while seated, could 

easily access the fire extinguishing 

means, and for certification levels 3 and 

4 airplanes, passengers would have a 

fire extinguishing means available 

within the passenger compartment. 

Where flammable fluids or vapors might 

escape by leakage of a fluid system, 

proposed § 23.800 would require each 

area, outside designated fire zones, be 

defined and have a means to make fluid 

and vapor ignition, and the resultant 

hazard, if ignition occurs, improbable. 

Additionally, proposed § 23.800 would 

also require combustion heater 

installations outside designated fire 

zones be protected from uncontained 

fire. 

Proposed § 23.800 would capture the 

safety intent of current §§ 23.851, Fire 

extinguishers, paragraphs (a) and (b); 

23.853, Passenger and crew 

compartment interiors, Paragraphs (a), 

(d)(3)(i), (d)(3)(iii) and (d)(3)(iv), (e), and 

(f); 23.855, Cargo and baggage 

compartment fire protection; 23.856, 

Thermal/acoustic insulation materials; 

23.859, Combustion heater fire 

protection, paragraph (a); 23.863, 

Flammable fluid fire protection, 

paragraphs (a) and (d); 23.1359, 

Electrical system fire protection, 

paragraph (c); 23.1365, Electric cables 

and equipment, paragraph (b); 23.1383, 

Taxi and landing lights, paragraph (d); 

23.1385, Position light system 

installation, paragraph (d). It would also 

capture the safety intent of CS–VLA– 

853, Compartment interiors. Proposed 

§ 23.800 would incorporate the 

requirements for flammability of all 

subpart D and F systems and equipment 

outside designated fire zones needed for 

continued safe flight and landing and 

remove specified design solutions and 

means of compliances. 

vii. Proposed § 23.805, Fire Protection 

in Designated Fire Zones 

Proposed § 23.805 would require 

flight controls, engine mounts, and 

other flight structures within or adjacent 

to designated fire zones be capable of 

withstanding the effects of a fire. 

Proposed § 23.805 would require 

engines inside designated fire zones to 

remain attached to the airplane in the 

event of a fire or electrical arcing. 

Proposed § 23.805 would also require 

terminals, equipment, and electrical 

cables, inside designated fire zones, 

used during emergency procedures, be 

fire-resistant. 

Proposed § 23.805 would capture the 

safety intent of current § 23.865, Fire 

protection of flight controls, engine 

mounts, and other flight structure and 

§ 23.1359(b), Electrical system fire 

protection. The intent of proposed 

§ 23.805 is to protect flight controls, 

engine mounts, and other flight 

structure as well as electrical cables, 

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terminals and equipment from the 

effects of fire in designated fire zones. 

viii. Proposed § 23.810, Lightning 

Protection of Structure 

Proposed § 23.810 would preclude 

primary structure failure caused by 

exposure to the direct effects of 

lightning, that could prevent continued 

safe flight and landing for airplanes 

approved for IFR. Proposed § 23.810 

would require airplanes approved only 

for VFR to achieve lightning protection 

by following FAA accepted design 

practices found in FAA issued advisory 

circulars and in FAA accepted 

consensus standards. 

Proposed § 23.810 would capture the 

safety intent of the current § 23.867(a) 

and (c), Electrical bonding and 

protection against lightning and static 

electricity. The FAA proposes adopting 

the structure requirements in part 23, 

amendment 23–7 (34 FR 13078, August 

13, 1969), to limit the rule to protection 

of primary structure from direct effects 

of lightning. 

ix. Reorganization of Subpart D 

The FAA proposes relocating the 

underlying safety. intent of various 

subpart D sections with proposed 

sections in subparts B, C, F, and G. The 

following table shows where the FAA 

proposes moving the current subpart D 

sections in part 23. 

Current section Title Proposed section Proposed title 

23.601 .................................. General .................................................... 23.500 ................................ Structural design. 

23.603 .................................. Materials and workmanship .................... 23.500 ................................ Structural design. 

23.605 .................................. Fabrication methods ................................ 23.510 ................................ Materials and processes. 

23.607 .................................. Fasteners ................................................. 23.505 ................................ Protection of structure. 

23.609 .................................. Protection of Structure ............................ 23.505 ................................ Protection of structure. 

23.611 .................................. Accessibility ............................................. 23.505 ................................ Protection of structure. 

23.613 .................................. Material strength properties and design 

values.

23.510 ................................ Materials and processes. 

23.619 .................................. Special factors ......................................... 23.515 ................................ Special factors of safety. 

23.621 .................................. Casting factors ........................................ 23.515 ................................ Special factors of safety. 

23.623. ................................. Bearing factors ........................................ 23.515 ................................ Special factors of safety. 

23.625 .................................. Fitting factors ........................................... 23.515 ................................ Special factors of safety. 

23.627 .................................. Fatigue strength ...................................... 23.405 ................................ Structural durability. 

23.629 .................................. Flutter ...................................................... 23.410 ................................ Aeroelasticity. 

23.641 .................................. Proof of strength ...................................... Means of Compliance.

23.651 .................................. Proof of strength ...................................... Means of Compliance.

23.655 .................................. Installation ............................................... Means of Compliance.

23.657 .................................. Hinges ..................................................... 23.515 ................................ Special factors of safety. 

23.659 .................................. Mass balance .......................................... 23.315 ................................ Flight load conditions. 

23.671 .................................. Control Surfaces—General.

(a) ........................................ .................................................................. 23.500 ................................ Structural design. 

(b) ........................................ .................................................................. 23.1305 .............................. Function and installation. 

23.672 .................................. Stability augmentation and automatic 

and power-operated systems.

23.1305 .............................. Function and installation. 

23.673 .................................. Primary flight controls .............................. 23.1305 .............................. Function and installation. 

23.675 .................................. Stops ....................................................... 23.1305 .............................. Function and installation. 

23.677 .................................. Trim systems.

(a) ........................................ .................................................................. 23.700 ................................ Flight control systems. 

(b) ........................................ .................................................................. 23.700 ................................ Flight control systems. 

(c) ......................................... .................................................................. 23.410 ................................ Aeroelasticity. 

(d) ........................................ .................................................................. 23.700 ................................ Flight control systems. 

23.679 .................................. Control system locks ............................... 23.1305 .............................. Function and installation. 

23.681(a) ............................. Limit load static tests ............................... 23.325(b) ........................... Component loading conditions. 

23.681(b) ............................. Limit load static tests ............................... 23.515 ................................ Special factors of safety. 

23.683 .................................. Operation tests ........................................ 23.500(d) ........................... Structural design. 

23.685(a), (b), (c) ................ Control system details ............................. 23.500(d) ........................... Structural design. 

23.685(d) ............................. Control system details ............................. 23.1305 .............................. Function and installation. 

23.687 .................................. Spring devices ......................................... 23.410 and 23.500 ............ Aeroelasticity and Structural design. 

23.689 .................................. Cable systems ......................................... ............................................ Component loading conditions, Structural design, and Equipment Systems 

and Installations. 

(a) ........................................ .................................................................. 23.700 ................................ Flight control systems. 

(b) ........................................ .................................................................. 23.325(b), 23.500(d) .......... Component loading conditions, Structural design. 

(c) ......................................... .................................................................. 23.325(b), 23.500(d) .......... Component loading conditions, Structural design. 

(d) ........................................ .................................................................. 23.325(b), 23.500(d) .......... Component loading conditions, Structural design. 

(e) ........................................ .................................................................. 23.325(b), 23.500(d) .......... Component loading conditions, Structural design. 

(f) ......................................... .................................................................. 23.700 ................................ Flight control systems. 

23.691 .................................. Artificial stall barrier system.

(a) ........................................ .................................................................. 23.700 ................................ Flight control systems. 

(b) ........................................ .................................................................. 23.700 ................................ Flight control systems. 

(c) ......................................... .................................................................. 23.1305 .............................. Function and installation. 

(d) ........................................ .................................................................. 23.700 ................................ Flight control systems. 

(e) ........................................ .................................................................. 23.700 ................................ Flight control systems. 

(f) ......................................... .................................................................. 23.700 ................................ Flight control systems. 

(g) ........................................ .................................................................. 23.1315 .............................. Equipment, systems and Installations. 

23.693 .................................. Joints ....................................................... 23.515 ................................ Special factors of safety. 

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Current section Title Proposed section Proposed title 

23.697 .................................. Wing flap controls.

(a) ........................................ .................................................................. 23.700 ................................ Flight control systems. 

(b) and (c) ............................ .................................................................. 23.200 ................................ Controllability. 

23.699 .................................. Wing flap position indicator ..................... 23.1500 .............................. Flightcrew interface. 

23.701 .................................. Flap interconnection ................................ Means of Compliance.

23.703 .................................. Takeoff warning system.

(a) ........................................ .................................................................. 23.700 ................................ Flight control systems. 

(b) ........................................ .................................................................. 23.700 ................................ Flight control systems. 

(c) ......................................... .................................................................. Definition.

23.721 .................................. General .................................................... 23.910 ................................ Powerplant installation hazard assessment. 

23.723. ................................. Shock absorption tests ............................ Means of Compliance.

23.725 .................................. Limit drop tests ........................................ Means of Compliance.

23.726 .................................. Ground load dynamic tests ..................... Means of Compliance.

23.727 .................................. Reserve energy absorption drop tests .... Means of Compliance.

23.729 .................................. Landing gear extension and retraction 

system.

(a) ........................................ .................................................................. 23.705 ................................ Landing gear systems. 

(b) ........................................ .................................................................. 23.705 ................................ Landing gear systems. 

(c) ......................................... .................................................................. 23.705 ................................ Landing gear systems. 

(d) ........................................ .................................................................. Means of Compliance.

(e) ........................................ .................................................................. 23.705 ................................ Landing gear systems. 

(f) ......................................... .................................................................. 23.1315 .............................. Equipment, systems and installation. 

(g) ........................................ .................................................................. Means of Compliance.

23.731 .................................. Wheels ..................................................... 23.705 ................................ Landing gear systems. 

23.733 .................................. Tires.

(a) ........................................ .................................................................. 23.705 ................................ Landing gear systems. 

(b) ........................................ .................................................................. Means of Compliance.

(c) ......................................... .................................................................. Means of Compliance.

23.735 .................................. Brakes ..................................................... 23.705.

(a) ........................................ .................................................................. 23.705 ................................ Landing gear systems. 

(1) ........................................ .................................................................. Means of Compliance.

(2) ........................................ .................................................................. Means of Compliance.

(b) ........................................ .................................................................. 23.705 ................................ Landing gear systems. 

(c) ......................................... .................................................................. Means of Compliance.

(d) ........................................ .................................................................. 23.1315 .............................. Equipment, systems and installation. 

(e) ........................................ .................................................................. 23.705 ................................ Landing gear systems. 

(1) ........................................ .................................................................. Means of Compliance.

(2) ........................................ .................................................................. Means of Compliance.

23.737 .................................. Skis .......................................................... 23.705 ................................ Landing gear systems. 

23.745 .................................. Nose/Tail wheel steering ......................... 23.1500 .............................. Flightcrew interface. 

23.751 .................................. Main float buoyancy.

(a) ........................................ .................................................................. 710 ..................................... Buoyancy for seaplanes and amphibians. 

(b) ........................................ .................................................................. Means of Compliance.

23.753 .................................. Main float design. .................................... 23.320 ................................ Ground and water load conditions. 

23.755 .................................. Hulls ......................................................... 23.710 ................................ Buoyancy for seaplanes and amphibians. 

23.757 .................................. Auxiliary floats ......................................... 23.710 ................................ Buoyancy for seaplanes and amphibians. 

23.771 .................................. Pilot compartment.

(a) ........................................ .................................................................. 23.1500 .............................. Flightcrew interface. 

(b) ........................................ .................................................................. 23.755 ................................ Occupant physical environment. 

(c ) ....................................... .................................................................. 23.755 ................................ Occupant physical environment. 

23.773 .................................. Pilot compartment view.

(a) ........................................ .................................................................. 23.1500 .............................. Flightcrew interface. 

(b) ........................................ .................................................................. 23.755 ................................ Occupant physical environment. 

23.775 .................................. Windshields and windows.

(a), (b), (c), (d) ..................... .................................................................. 23.755 ................................ Occupant physical environment. 

(e) ........................................ .................................................................. Means of Compliance.

(f) ......................................... .................................................................. 23.1405 .............................. Flight in icing conditions. 

(g) ........................................ .................................................................. Means of Compliance.

(h) ........................................ .................................................................. 23.755 ................................ Occupant physical environment. 

23.777 .................................. Cockpit controls ....................................... 23.1500 .............................. Flightcrew interface. 

23.779 .................................. Motion and effect of cockpit controls ...... 23.1500 .............................. Flightcrew interface. 

23.781 .................................. Cockpit control knob shape ..................... 23.1500 .............................. Flightcrew interface. 

23.783 .................................. Doors.

(a), (b), (c), (d) ..................... .................................................................. 23.750 ................................ Means of egress and emergency exits. 

(e), (f), (g) ............................ .................................................................. Means of Compliance.

23.785 .................................. Seats, berths, litters, safety belts, and 

shoulder harnesses.

23.600 and 23.515 ............ Special factors of safety, Emergency 

landing conditions. 

23.787 .................................. Baggage and cargo compartments ......... 23.600(e) ........................... Emergency landing conditions. 

23.791 .................................. Passenger information signs ................... 23.755 ................................ Occupant physical environment. 

23.803 .................................. Emergency evacuation.

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24Refer to Section III, Discussion of Proposal, 

paragraphs A and B of this NPRM for definition and 

discussion of a simple airplane. 

Current section Title Proposed section Proposed title 

(a) ........................................ .................................................................. 23.750 ................................ Means of egress and emergency exits. 

(b) ........................................ .................................................................. Means of Compliance.

23.805 .................................. Flightcrew emergency exits ..................... 23.750 ................................ Means of egress and emergency exits. 

23.807 .................................. Emergency exits.

(a)(3 ), (b)(1), (c), (d)(1), 

(d)(4).

.................................................................. Means of Compliance.

Balance of 23.807 ............... .................................................................. 23.750 ................................ Means of egress and emergency exits. 

23.811 .................................. Emergency exit marking .......................... 23.750 ................................ Means of egress and emergency exits. 

23.812 .................................. Emergency lighting .................................. 23.750 ................................ Means of egress and emergency exits. 

23.813 .................................. Emergency exit access.

(a) ........................................ .................................................................. 23.750 ................................ Means of egress and emergency exits. 

(b) ........................................ .................................................................. Means of Compliance.

CS–VLA 853 ........................ .................................................................. 23.750 ................................ Means of egress and emergency exits. 

23.815 .................................. Width of aisle ........................................... 23.750 ................................ Means of egress and emergency exits. 

23.831 .................................. Ventilation ................................................ 23.755 ................................ Occupant physical environment. 

23.841(a), (b)(6), (c), (d) ..... Pressurized cabins .................................. 23.755 ................................ Occupant physical environment. 

(b)(1) through (5) and (7) .... .................................................................. Means of Compliance.

23.843 .................................. Pressurization tests ................................. 23.755 ................................ Occupant physical environment. 

23.851 .................................. Fire extinguishers.

(a) and (b) ............................ .................................................................. 23.800 ................................ Fire protection outside designated fire 

zones. 

(c) ......................................... .................................................................. Means of Compliance.

23.853 .................................. Passenger and crew compartment interiors.

(a) ........................................ .................................................................. 23.800 ................................ Fire protection outside designated fire 

zones. 

(b)(c) and (d)(1)(2) ............... .................................................................. Means of Compliance.

(d)(3)(i), (d)(3)(iii), (d)(3)(iv) .................................................................. 23.800 ................................ Fire protection outside designated fire 

zones. 

(e) ........................................ .................................................................. 23.800 ................................ Fire protection outside designated fire 

zones. 

(f) ......................................... .................................................................. 23.800 ................................ Fire protection outside designated fire 

zones. 

23.855 .................................. Cargo and baggage compartment fire 

protection.

23.800 ................................ Fire protection outside designated fire 

zones. 

23.856 .................................. Thermal/acoustic insulation materials ..... 23.800 ................................ Fire protection outside designated fire 

zones. 

23.859 .................................. Combustion heater fire protection.

(a) ........................................ .................................................................. 23.800 ................................ Fire protection outside designated fire 

zones. 

(b) thru (i) ............................. .................................................................. Means of Compliance.

23.863 .................................. Flammable fluid fire protection.

(a) and (d) ............................ .................................................................. 23.800 ................................ Fire protection outside designated fire 

zones. 

(b) and (c) ............................ .................................................................. Means of Compliance ....... Fire protection outside designated fire 

zones. 

23.865 .................................. Fire protection of flight controls, engine 

mounts, and other flight structure.

23.805 ................................ Fire protection in designated fire zones. 

23.867 .................................. Electrical bonding and protection against 

lightning and static electricity.

(a), (c) .................................. .................................................................. 23.810 ................................ Lightning protection of structure. 

(b) ........................................ .................................................................. 23.1320 .............................. Electrical and electronic system lightning 

protection. 

23.871 .................................. Leveling means ....................................... Means of Compliance.

5. Subpart E—Powerplant 

a. General Discussion 

The FAA proposes substantial 

changes to subpart E based on two 

considerations. First, many of the 

current regulations could be combined 

to provide fewer regulations that 

accomplish the same safety intent. 

Second, part 23 overlaps with the 

requirements in parts 33 and 35. Refer 

to appendix 1 of this preamble for a 

cross-reference table detailing how the 

current regulations are addressed in the 

proposed part 23 regulations. 

b. Specific Discussion of Changes 

i. Proposed § 23.900, Powerplant 

Installation 

Proposed § 23.900 would clarify, for 

the purpose of this subpart, that the 

airplane powerplant installation must 

include each component necessary for 

propulsion, affects propulsion safety, or 

provides auxiliary power to the 

airplane. Proposed § 23.900 would 

require the applicant to construct and 

arrange each powerplant installation to 

account for likely hazards in operation 

and maintenance and, except for simple 

airplanes,24 each aircraft engine would 

have to be type certificated. 

Proposed § 23.900 would capture the 

safety intent of current §§ 23.901, 

Installation, paragraphs (a), (b), and (f); 

23.903, Engines, paragraph (a); 23.905, 

Propellers, paragraph (a), 23.909, 

Turbocharger systems, paragraphs (a) 

and (c); and 23.925, Propeller clearance. 

Proposed § 23.900 would combine the 

installation requirements that are 

scattered throughout the subpart into a 

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general requirement for installation, and 

remove any duplication with part 33. 

The following table illustrates the 

duplication between the current part 23 

regulations and part 33 requirements: 

Part 23 Part 33 

§ 23.901(d), Installation ............................................................................ § 33.33, Vibration. 

§ 23.901(e), Installation ............................................................................ § 33.1, Applicability. 

§ 23.934, Turbojet and turbofan engine thrust reverser systems tests ... § 33.97, Thrust reversers. 

§ 23.939, Powerplant operating characteristics ........................................ §§ 33.61 thru 33.79. 

§ 23.1011, Oil System—General .............................................................. §§ 33.39 and 33.71, Lubrication system. 

§ 23.1013(a) and (d), Oil tanks ................................................................. §§ 33.39, and 33.71, Lubrication system. 

§ 23.1015, Oil tank tests ........................................................................... § 33.33, Vibration. 

§ 23.1023, Oil radiators ............................................................................ § 33.33, Vibration. 

§ 23.1041, Cooling—General ................................................................... § 33.1, Applicability. 

§ 23.1043, Cooling tests ........................................................................... §§ 33.41 and 33.81, Applicability—Block Tests. 

§ 23.1045, Cooling test procedures for turbine engine powered airplanes.§ 33.81, Applicability—Block Tests. 

§ 23.1047, Cooling test procedures for reciprocating engine powered 

airplanes.

§ 33.35, Fuel and induction system. 

§ 23.1061, Liquid Cooling—Installation .................................................... § 33.21, Engine cooling. 

§ 23.1063, Coolant tank tests ................................................................... § 33.41 and 33.81, Applicability—Block Tests. 

§ 23.1093, Induction system icing protection ........................................... §§ 33.35(b), Fuel and induction system and 33.68, Induction system 

icing. 

§ 23.1099, Carburetor deicing fluid system detail design ........................ § 33.35, Fuel and induction system. 

Additionally, proposed § 23.900 

would identify the scope of the 

powerplant installation in the same 

manner as the current requirements. 

However, the FAA would redefine 

several terms to allow for alternate 

sources of propulsion, such as electric 

motors. The FAA considers the term 

powerplant to include all equipment 

used by the airplane that provides 

propulsion or auxiliary power. The 

word engine would be replaced with the 

term power unit and would include 

other power sources driven by fuel such 

as liquid fuel, electrical, or other power 

sources not yet envisioned. This 

proposal also predicates that each 

airplane power unit or propeller receive 

a type certificate as a prerequisite for 

installation, with the exception of 

simple airplanes. The current part 33 

airworthiness standards did not 

envision providing certification 

requirements for types of engines 

outside of those that operate on fossil 

fuels. As such, the ability of an 

applicant to obtain the required engine 

type certificate for an alternate fuel type 

may be impractical. For those power 

units, the FAA proposes to include 

them in the airplane certification, which 

could include the use of an ELOS to part 

23. The FAA would expect an applicant 

to utilize all the requirements listed in 

part 33 as a baseline matrix to find 

compliance for an alternate powerplant 

type and for those requirements that 

could not be met. Also, § 21.16, Special 

conditions, may apply. It should be 

noted that additional requirements 

might also be necessary due to an 

absence of a corresponding part 33 

requirement. This matrix would become 

part of the certification baseline and 

recorded in an issue paper as an ELOS, 

exemption, or special condition. Also, 

simple airplanes will follow the 

precedence set for CS–VLA and will 

maintain the exception to the 

requirement to be type certificated. 

ii. Proposed § 23.905, Propeller 

Installation 

Proposed § 23.905 would retain the 

requirement that each propeller be type 

certificated, except for simple airplanes. 

Proposed § 23.905 would retain the 

requirement that each pusher propeller 

be marked so that it is conspicuous 

under daylight conditions. All the other 

requirements of the current section 

either duplicate part 35 standards, or 

would condense into the other 

requirements proposed in §§ 23.900, 

Powerplant installation; 23.910, 

Powerplant installation hazard 

assessment; and 23.940, Powerplant ice 

protection. 

iii. Proposed § 23.910, Powerplant 

Installation Hazard Assessment 

Proposed § 23.910 would require an 

applicant to assess each powerplant 

separately and in relation to other 

airplane systems and installations to 

show that a failure of any powerplant 

system component or accessory will 

not— 

• Prevent continued safe flight and 

landing; 

• Cause serious injury; and 

• Require immediate action by 

crewmembers for continued operation 

of any remaining powerplant system. 

Proposed § 23.910 would capture the 

safety intent of current §§ 23.721, 

Landing gear—General; 23.903, Engines, 

paragraph (c); 23.905, Propellers, 

paragraph (h); 23.909, Turbocharger 

systems, paragraph (b), (c), and (e); 

23.933 Reversing systems, paragraph (b); 

23.937, Turbopropeller-drag limiting 

systems, paragraph (a); 23.959, 

Unusable fuel supply; 23.979, Pressure 

fueling systems, paragraphs (c) and (d); 

23.991, Fuel pumps, paragraph (d); 

23.994, Fuel system components; 

23.1001, Fuel jettisoning system, 

paragraph (h); 23.1027, Propeller 

feathering system; 23.1111, Turbine 

engine, paragraph (a) and (c); 23.1123, 

Exhaust system; 23.1125 Exhaust heat 

exchangers, paragraph (a); 23.1142, 

Auxiliary power unit controls, 

paragraphs (d) and (e); 23.1155, Turbine 

engine reverse thrust and propeller 

pitch settings below the flight regime; 

23.1163, Powerplant accessories, 

paragraphs (b) and (d); 23.1191, 

Firewalls, paragraph (f); 23.1193, 

Cowling and nacelle, paragraphs (f) and 

(g); 23.1201, Fire extinguishing systems 

materials, paragraph (a); and 23.1203, 

Fire detector system, paragraphs (b) and 

(c). 

The proposed standard would reduce 

the repetitive requirements found 

throughout the subpart and create one 

general powerplant requirement to 

analyze and mitigate hazards associated 

with the powerplant installation. For 

example, current § 23.903(b)(1) requires 

that design precautions be taken to 

minimize the hazards to the airplane in 

the event of an engine rotor failure or a 

fire originating inside the engine that 

could burn though the engine case. 

These are very specific failure 

conditions, but are actually only two 

small categories of many engine failure 

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conditions an applicant must assess. 

Section 23.903(c) requires that multiple 

engines must be isolated from one 

another so a malfunction of one engine 

does not affect the operation of the 

other. This is a general analysis 

technique frequently called common 

mode analysis that should apply to all 

powerplant components and include 

other critical airplane systems that are 

not powerplant related, but could be 

affected by a powerplant failure. 

Hazards the FAA proposes to remove 

from other regulations and which would 

be addressed in this proposed section 

include, but are not limited to, fire, ice, 

rain and bird ingestion, rotorburst, 

engine case burn through, and 

flammable leakage. 

iv. Proposed § 23.915, Automatic Power 

Control Systems 

Proposed § 23.915 would require a 

power or thrust augmentation system 

that automatically controls the power or 

thrust on the operating powerplant to 

provide an indication to the flightcrew 

when the system is operating; provide a 

means for the pilot to deactivate the 

automatic functions; and prevent 

inadvertent deactivation. 

Proposed § 23.915 would capture the 

safety intent of current § 23.904, 

Automatic power reserve system and 

appendix H to part 23—Installation of 

An Automatic Power Reserve (APR) 

System. To foster the growth and 

approval of technological advances, the 

FAA believes that the detailed and 

prescriptive language of appendix H is 

more appropriate as means of 

compliance. We would also include 

requirements for thrust augmenting 

systems into this proposed section since 

there seems to be a trend in general 

aviation to provide thrust management 

systems more sophisticated than 

historical automatic power reserve 

systems. 

v. Proposed § 23.920, Reversing Systems 

Proposed § 23.920 would require an 

airplane to be capable of continued safe 

flight and landing under any available 

reversing system setting, and would 

capture the safety intent of current 

§ 23.933(a) and (b). The current rule 

includes a separate requirement for a 

propeller reversing system that would 

be covered in the more general language 

of the proposed section and applied to 

any type of reverser system. Current 

§ 23.933 also requires an analysis of the 

system for a failure condition. Those 

provisions would be addressed in the 

general analysis requirements of 

proposed § 23.910. 

vi. Proposed § 23.925, Powerplant 

Operational Characteristics 

Proposed § 23.925 would require the 

powerplant to operate at any negative 

acceleration that could occur during 

normal and emergency operation within 

the airplane operating limitations. 

Proposed § 23.925 would require the 

pilot to have the capability to stop and 

restart the powerplant in flight. 

Proposed § 23.925 would require the 

airplane to have an independent power 

source for restarting each powerplant 

following an in-flight shutdown. 

Proposed § 23.925 would capture the 

safety intent of current §§ 23.903, 

Engines, paragraph (d), (e), (f), and (g); 

23.939, Powerplant operating 

characteristics; and 23.943, Negative 

acceleration. Current § 23.939 addresses 

powerplant operating characteristics 

and clearly requires an analysis that 

would be required by proposed § 23.910 

and the existing requirements of part 33. 

Current § 23.943 would be included in 

this proposed rule because it is another 

analysis requirement, and one that 

provides an environment where 

powerplant systems are required to 

operate. 

vii. Proposed § 23.930, Fuel Systems 

Proposed § 23.930 would require that 

each fuel system provide an 

independent fuel supply to each 

powerplant in at least one configuration 

and prevent ignition from an unknown 

source. This section would require that 

each fuel system provide the fuel 

required to achieve maximum power or 

thrust plus a margin for likely variables 

in all temperature conditions within the 

operating envelope of the airplane and 

provide a means to remove the fuel from 

the airplane. Proposed § 23.930 would 

require each fuel system to be capable 

of retaining fuel when subject to inertia 

loads under expected operating 

conditions and prevent hazardous 

contamination of the fuel supply. 

Proposed § 23.930 would require each 

fuel storage system to withstand the 

loads and pressures under expected 

operating conditions and provide a 

means to prevent loss of fuel during any 

maneuver under operating conditions 

for which certification is requested. 

Also, proposed § 23.930 would require 

each fuel storage system to prevent 

discharge when transferring fuel, 

provide fuel for at least one-half hour of 

operation at maximum continuous 

power or thrust, and be capable of 

jettisoning fuel, if required for landing. 

Proposed § 23.930 would require 

installed pressure refueling systems to 

have a means to prevent the escape of 

hazardous quantities of fuel, 

automatically shut-off before exceeding 

the maximum fuel quantity of the 

airplane, and provide an indication of a 

failure at the fueling station. Proposed 

§ 23.930 would capture the safety intent 

of current §§ 23.951, Fuel System— 

General, paragraphs (a), (b), (c), and (d); 

23.953, Fuel System; 23.954, Fuel 

system lightning protection; 23.955, 

Fuel flow; 23.957, Flow between 

interconnected tanks, paragraph (a); 

23.961, Fuel system hot weather 

operation; 23.963, Fuel tanks: General, 

paragraphs (a), (d), and (e); 23.977, Fuel 

tank outlet; 23.979, Pressure fueling 

systems, paragraphs (a) and (b); 23.991, 

Fuel pumps, paragraphs (a), (b), and (c); 

23.997, Fuel strainer or filter, 

paragraphs (a), (b), (c), and (d); 23.999, 

Fuel system drains; and 23.1001, Fuel 

jettisoning system, paragraph (a). 

The FAA believes that the regulations 

for the design of fuel systems may be 

overly prescriptive and exceed what is 

necessary to design a safe system. 

Accordingly, a more general set of 

requirements could include the intent of 

many current rules. More importantly, 

this proposed rule would allow for other 

types of energy sources to power 

propulsion systems such as electrical 

motors and future energy sources. 

viii. Proposed § 23.935, Powerplant 

Induction and Exhaust Systems 

Proposed § 23.935 would require the 

air induction system to supply the air 

required for each power unit and its 

accessories under expected operating 

conditions, and provide a means to 

discharge potential harmful material. 

Proposed § 23.935 would capture the 

safety intent of current §§ 23.1091, Air 

induction system, paragraph (a); 

23.1101, Induction air preheater design, 

paragraph (a); 23.1103, Induction 

system ducts; 23.1107, Induction system 

filters; and 23.1121, Exhaust System— 

General, paragraphs (a) through (g). This 

proposed rule would combine induction 

and exhaust systems into a single rule 

because of the commonality with issues 

associated with moving air. The 

prescriptive language of the regulations 

identified above in this paragraph drove 

the development of this proposed 

section. For example, § 23.1091(b) 

mandates a certain number of intake 

sources and specifies particular 

requirements for a primary and alternate 

intakes. Current § 23.1101 requires 

inspection access of critical parts, and 

current § 23.1103 is considered a part of 

a proper safety analysis that would be 

required by proposed § 23.910. 

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ix. Proposed § 23.940, Powerplant Ice 

Protection 

Proposed § 23.940 would require the 

airplane design, including the engine 

induction system, to prevent foreseeable 

accumulation of ice or snow that would 

adversely affect powerplant operation. 

Proposed § 23.940 would also require 

the applicant design the powerplant to 

prevent any accumulation of ice or 

snow that would adversely affect 

powerplant operation, in those icing 

conditions for which certification is 

requested. Proposed § 23.940 would 

capture the safety intent of current 

§§ 23.905, Propellers, paragraph (e); 

23.929, Engine installation ice 

protection; 23.975, Fuel tank vents and 

carburetor vapor vents, paragraph (a)(1); 

23.1093, Induction system icing 

protection; 23.1095, Carburetor deicing 

fluid flow rate; 23.1097, Carburetor 

deicing fluid system capacity; and 

23.1099, Carburetor deicing fluid system 

detail design. 

Proposed § 23.940(a) would reflect the 

requirements in current § 23.1093, 

which applies to all airplanes, 

regardless if flight in icing certification 

is sought. We are proposing to remove 

the type of powerplant to accommodate 

for new powerplant technologies. In 

addition, we propose to define other 

foreseeable icing in the means of 

compliance, which would include 

conditions conducive to induction icing 

of reciprocating engines. Foreseeable 

icing in the means of compliance would 

also include the cloud icing conditions 

of appendix C to part 25, currently 

defined in § 23.1093(b)(1)(i), falling and 

blowing snow currently defined in 

§ 23.1093(b)(1)(ii), and ground ice fog 

conditions currently defined in 

§ 23.1093(b)(2). The FAA proposes to 

remove the prescriptive requirements of 

the current §§ 23.1093(a), 23.1095, 

23.1097, and 23.1099 as these are more 

appropriately considered as means of 

compliance. The FAA would expect the 

means of compliance to expand the 

ground ice fog conditions to colder 

ambient temperatures to harmonize 

with EASA. The FAA would also expect 

the means of compliance to include 

optional ground and flight freezing 

drizzle and freezing rain conditions, 

similar to appendix O of part 25, for 

those airplanes that seek certification to 

operate in those conditions. The Part 23 

Icing ARC had recommended specific 

pass/fail criteria for the effect of ice 

accretion on engine operation. The FAA 

would expect this criterion to be 

defined in a means of compliance. 

Proposed paragraph (a) would require 

an airplane design to prevent 

‘‘foreseeable’’ ice or snow accumulation, 

including accumulation in inadvertent 

icing encounters, described in appendix 

C to part 25, on airplanes not certified 

for icing, which may pose a shed hazard 

to the powerplant. 

Airplane design in proposed 

§ 23.940(a) refers to the engine 

induction system and airframe 

components on which accumulated ice 

may shed into the powerplant. 

Powerplant design in proposed 

§ 23.940(b) refers to the engine, 

propeller, and other powerplant 

components such as cooling inlets. 

Proposed § 23.940(b) would apply 

only to airplanes certified for flight in 

icing and would require compliance to 

the icing requirements in part 33, which 

currently only apply to turbine engines. 

Part 33, amendment 33–34 (79 FR 

65507, November 4, 2014) and effective 

January 5, 2015, added SLD and ice 

crystal requirements to § 33.68 and 

amended the engine ice ingestion 

requirements in § 33.77. Proposed 

§ 23.940(b) would require installation of 

an engine(s) certified to § 33.68 

amendment 33–34, or later, if the 

airplane will be certified for flight in 

freezing drizzle and freezing rain. 

Proposed § 23.940(b) would allow an 

airplane manufacturer to install an 

engine, type certified at an earlier 

amendment, in an airplane not certified 

for flight in freezing drizzle or freezing 

rain, as long as no ADs have been 

applied that relate to engine operation 

in inadvertent SLD or ice crystal 

conditions. Airplanes certified under 

part 23 have not had ADs related to SLD 

or ice crystals. Certain part 23 turbojet 

engines have experienced thrust 

rollback due to ice crystals blocking the 

heated inlet temperature probe. The 

FAA would expect the means of 

compliance to address this in a similar 

manner to what is accomplished on 

current certification projects. The 

engine ice ingestion requirements of the 

current § 23.903(a)(2) would be moved 

to proposed § 23.940(b). 

x. Proposed § 23.1000, Powerplant Fire 

Protection 

Proposed § 23.1000 would require 

that a powerplant only be installed in a 

designated fire zone and would require 

an applicant to install a fire detection 

system in each designated fire zone for 

certification levels 3 and 4 airplanes. 

This rulemaking effort is maintaining 

the current level of safety for fire 

protection. While not a perfect one-toone relationship, airplanes equivalent to 

certification levels 1 and 2 airplanes are 

not required to have a fire detection 

system today and therefore, should not 

be required to have them in this 

proposed rule. This would increase the 

cost of certification. Each fire detection 

system would be required to provide a 

means to alert the flightcrew in the 

event of a detection of fire or failure of 

the system and a means to check the fire 

detection system in flight. Proposed 

§ 23.1000 would also require an 

applicant to install a fire extinguishing 

system for certification levels 2, 3, and 

4 airplanes with a powerplant located 

outside the pilot’s view that uses 

combustible fuel. 

Additionally, proposed § 23.1000 

would require each component, line, 

and fitting carrying flammable fluids, 

gases, or air subject to fire conditions to 

be fire resistant, except components 

storing concentrated flammable material 

would have to be fireproof or enclosed 

by a fireproof shield. Proposed 

§ 23.1000 would also require an 

applicant to provide a means to shut off 

fuel or flammable material for each 

powerplant, while not restricting fuel to 

remaining units, and prevent 

inadvertent operation. Proposed 

§ 23.1000 would capture the safety 

intent of current §§ 23.1181, Designated 

fire zones: Regions included; 23.1182, 

Nacelle areas behind firewalls; 23.1183, 

Lines, fittings, and components; 

23.1189, Shutoff means; 23.1191, 

Firewalls; 23.1192 Engine accessory 

compartment diaphragm; 23.1193, 

Cowling and nacelle; 23.1195, Fire 

extinguishing systems; 23.1197, Fire 

extinguishing agents; 23.1199, 

Extinguishing agent containers; 23.1201, 

Fire extinguishing system materials; and 

23.1203, Fire detector system. 

Regulations for fuel may have become 

too detailed and prescriptive. A more 

general set of requirements should 

capture the intent of these many rules. 

More importantly, this new proposed 

rule would allow other types of energy 

sources to power propulsion systems 

such as electrical motors and future 

energy sources. 

xi. Current Subpart E Regulations 

Relocated to Other Proposed Subparts 

The requirements of current 

§ 23.903(b)(1) would be moved to 

subpart C, § 23.405, Structural 

durability, paragraph (d). Section 

23.903(b)(1) requires design precautions 

for turbine engine installations to be 

taken to minimize hazards to the 

airplane in the event of an engine rotor 

failure or of a fire originating inside the 

engine which burns through the engine 

case. 

Additionally, the requirements of 

current § 23.929 would be moved to 

proposed § 23.940(b) and would only 

apply to airplanes certified for flight in 

icing. The means of compliance for 

§ 23.940(b) should address propeller ice 

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protection system design and analysis. 

However, the means of compliance for 

climb performance for proposed 

§ 23.230 should address ice accretion 

effects on propeller performance on 

airplanes certified for flight in icing. 

xii. Removal of Subpart E Current 

Regulations 

The following current regulations are 

considered duplicative of part 35 and 

would be removed from subpart E: 

§ 23.905(b)—duplicative of § 35.5, 

Propeller ratings and operation 

limitations; § 23.905(c)—duplicative of 

§ 35.22, Feathering propellers; 

§ 23.905(d)—duplicative of §§ 35.21, 

35.23, 35.42 and 35.43; and 

§ 23.905(e)(g) and (h)—duplicative of 

§ 35.7, Features and characteristics. 

6. Subpart F—Equipment 

a. General Discussion 

The proposed changes to subpart F 

would consolidate the current rules into 

new performance-based standards and 

allow for use of new technologies once 

consensus standards are developed that 

could be used as a means of 

compliance.The FAA believes the 

proposed part 23 requirements would 

maintain the current level of safety 

while staying relevant for new future 

technologies. The prescriptive design 

solutions in the current rules are often 

not relevant to new technology 

requiring special conditions, 

exemptions, and ELOS findings. The 

rate of new technology development 

and adoption has increased dramatically 

in the last decade. As a result, airplane 

systems with new features and 

capabilities are rapidly becoming 

available. The FAA believes that 

removing the prescriptive design 

solutions, which are based on outdated 

or existing technology, while focusing 

on the safety intent of the rule and 

maintaining design solutions as a 

documented means of compliance 

would enable the adoption of newer 

technologies. 

The FAA also believes the current 

part 23 regulatory prescriptive structure 

does not effectively address the safety 

continuum, particularly the low 

performance end of the continuum. 

Recent part 23 amendments have 

increasingly focused on highperformance, complex airplanes. These 

stricter requirements have also been 

applied to the low-performance 

airplanes even though their risk in the 

safety continuum is lower. This has 

created an unintended barrier to new 

safety enhancing technology in lowperformance airplanes. 

b. Specific Discussion of Changes 

i. Proposed § 23.1300, Airplane Level 

Systems Requirements 

Proposed § 23.1300 would require 

equipment and systems that are 

required for an airplane to operate 

safely, be designed and installed to meet 

the level of safety applicable to the 

certification and performance levels of 

the airplane, and to perform their 

intended function throughout the 

operating and environmental limits 

specified by an applicant. Proposed 

§ 23.1300 would mandate that 

non-required airplane equipment and 

systems, considered separately and in 

relation to other systems, be designed 

and installed so their operation or 

failure would not have an adverse effect 

on the airplane or its occupants. 

Proposed § 23.1300 would capture the 

safety intent found in portions of 

current §§ 23.1301, Function and 

installation; 23.1303, Flight and 

navigation instruments; 23.1305, 

Powerplant instruments; 23.1307, 

Miscellaneous equipment; 23.1309, 

Equipment, systems, and installations; 

23.1311, Electronic display instrument 

systems; 23.1321, Arrangement and 

visibility; 23.1323, Airspeed indicating 

system, 23.1325, Static pressure system; 

23.1327, Magnetic direction indicator; 

23.1329, Automatic pilot system; 

23.1335, Flight director systems; 

23.1337, Powerplant instruments 

installation; 23.1351, Electrical Systems 

and Equipment—General; 23.1353, 

Storage battery design and installation; 

and 23.1361, Master switch 

arrangement. 

The current requirements can be 

traced back to CAR 3, specifically CAR 

3.651, 3.652, 3.655, 3.661, 3.662, 3.663, 

3.665, 3.666, 3.667, 3.669, 3.670, 3.671, 

3.672, 3.673, 3.674, 3.681, 3.682, 3.686, 

3.687, and 3.683. These requirements, 

including § 23.1311, which does not 

have a corresponding rule in CAR 3, 

were based on the technology and 

design solutions available at the time of 

their adoption. Although these 

requirements are appropriate for 

traditional systems found in airplanes 

designed to these assumptions, they 

lack the flexibility to adopt current and 

anticipated technologies and design 

capabilities. The FAA wants to facilitate 

the use of systems in new airplanes that 

reduce pilot workload and enhance 

safety. The FAA proposes the use of 

performance-based language that 

maintains the level of safety achieved 

with the current requirements for 

traditionally designed airplanes but also 

allows for alternative system designs in 

the future. 

Proposed § 23.1300(a) would address 

equipment and systems required to 

operate safely. Required equipment may 

be defined by other parts such as part 

91 or part 135, by other sections of this 

part such as equipment necessary for 

flight into known icing, or other 

requirements placed on the Type 

Certificate Data Sheet (TCDS) such as a 

working autopilot for single pilot 

operations. The FAA proposes in 

§ 23.1300(b) that non-required 

equipment may be installed because it 

offers some benefit and its failure or use 

would not result in a reduction in safety 

of the airplane or for its occupants from 

the base aircraft if the system was not 

installed. This proposed section would 

contain general requirements for the 

environmental qualifications of 

installed equipment, and would require 

installed equipment to perform its 

intended function over its defined 

environmental range. This would mean 

that the equipment should have the 

same environmental qualification as 

requested for the useful range of the 

airplane. 

Proposed § 23.1300(b) would not 

mandate that non-required equipment 

and systems function properly during 

all airplane operations once in service, 

provided all potential failure conditions 

do not effect safe operation of the 

airplane. The equipment or system 

would have to function in the manner 

expected by the manufacturer’s 

operating manual for the equipment or 

system. An applicant’s statement of 

intended function would have to be 

sufficiently specific and detailed so that 

the FAA could evaluate whether the 

system was appropriate for the intended 

function. 

ii. Proposed § 23.1305, Function and 

Installation 

Proposed § 23.1305 would require 

that each item of installed equipment 

perform its intended function, be 

installed according to limitations 

specified for that equipment, and the 

equipment be labeled, if applicable, due 

to size, location, or lack of clarity as to 

its intended function, as to its 

identification, function or operating 

limitations, or any combination of these 

factors. Proposed § 23.1305 would 

require a discernable means of 

providing system operating parameters 

required to operate the airplane, 

including warnings, cautions, and 

normal indications to the responsible 

crewmember. Proposed § 23.1305 would 

require information concerning an 

unsafe system operating condition be 

provided in a clear and timely manner 

to the crewmember responsible for 

taking corrective action. 

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25See Accident and GA Safety reports from 

NTSB, AOPA Safety Foundation, and the General 

Aviation Joint Steering Committee (GA–JSC) over 

the past 10 years. 

Proposed § 23.1305 would capture the 

safety intent found in portions of the 

current §§ 23.671, Control systemsGeneral; 23.672, Stability augmentation 

and automatic and power-operated 

systems; 23.673, Primary flight controls; 

23.675, Stops; 23.679, Control system 

locks; 23.685(d), Control system details; 

23.691(c), Artificial stall barrier system; 

23.1361, Master switch arrangement; 

and 23.1365(a) and (b), Electric cables 

and equipment; 23.1301, Function and 

installation; 23.1303, Flight and 

navigation instruments; 23.1305, 

Powerplant instruments; 23.1309, 

Equipment, systems, and installations; 

23.1322, Warning, caution, and advisory 

lights; 23.1323, Airspeed indicating 

system; 23.1326, Pitot heat indication 

systems; 23.1327, Magnetic direction 

indicator; 23.1329, Automatic pilot 

system; 23.1331, Instruments using a 

power source; 23.1335, Flight director 

systems; 23.1337, Powerplant 

instruments installation; 23.1351, 

Electrical Systems and Equipment— 

General; 23.1353, Storage battery design 

and installation; 23.1365, Electric cables 

and equipment; 23.1367, Switches; 

23.1416, Pneumatic de-icer boot system. 

The current requirements can be traced 

to CAR 3, specifically, CAR 3.651, 

3.652, 3.655, 3.663, 3.666, 3.667, 3.668, 

3.669, 3.670, 3.671, 3.672, 3.673, 3.674, 

3.675, 3.681, 3.682, 3.683, 3.686, 3.687, 

3.693, 3.694, 3.696, 3.697, 3.700, 3.712, 

and 3.726. These requirements, 

including §§ 23.1322, 23.1326, and 

23.1441, which did not have 

corresponding rules in CAR 3, were 

based on the technology and design 

solutions available at the time of their 

adoption. Although these requirements 

are appropriate for traditional systems 

and designs found in airplanes designed 

to these assumptions, they lack the 

flexibility to adopt current and 

anticipated technologies and design 

capabilities. The FAA wants to facilitate 

the use of systems in new airplanes that 

reduce pilot workload and enhance 

safety. The FAA proposes the use of 

performance-based language that 

maintains the safety requirements for 

traditionally designed airplanes, but 

also allows for alternative system 

designs. 

The equipment or system would have 

to function in the manner expected by 

the manufacturer’s operating manual for 

the equipment or system. An applicant’s 

statement of intended function would 

have to be sufficiently specific and 

detailed so that the FAA could evaluate 

whether the system was appropriate for 

the intended function. The equipment 

should function when installed as 

intended by the manufacturer’s 

instructions. The intent is for an 

applicant to define proper functionality 

and to propose an acceptable means of 

compliance. 

Proposed § 23.1305(a) would require 

that equipment be installed under 

prescribed limitations. Therefore, if an 

equipment manufacturer specified any 

allowable installation requirements, the 

installer would stay within the 

limitations or substantiate the new 

limits. The proposed requirement that 

the equipment be labeled as to its 

identification, function or operating 

limitations, or any combination of these 

factors, if applicable, would apply to the 

manufacturer of the equipment, not to 

the installer. 

Proposed § 23.1305 would require 

that information concerning an unsafe 

system operating condition be provided 

to the flightcrew. Microprocessing units 

that monitor parameters and warn of 

system problems have already been 

incorporated in some airplanes and are 

used by other industries, including the 

automobile and nuclear energy fields. 

Pilots may not monitor gauges as they 

used to; instead, they could rely on 

warnings and alerts. The FAA does not 

propose to allow simple on-off failure 

lights to replace critical trend displays. 

Warning systems would need to be 

sophisticated enough to read transients 

and trends, when appropriate, and give 

useful warning to the flightcrew. 

iii. Proposed § 23.1310, Flight, 

Navigation, and Powerplant Instruments 

Proposed § 23.1310 would require 

installed systems to provide the 

flightcrew member who sets or monitors 

flight parameters for the flight, 

navigation, and powerplant information 

necessary to do so during each phase of 

flight. Proposed § 23.1310 would require 

this information include parameters and 

trends, as needed for normal, abnormal, 

and emergency operation, and 

limitations, unless an applicant showed 

the limitation would not be exceeded in 

all intended operations. Proposed 

§ 23.1310 would prohibit indication 

systems that integrate the display of 

flight or powerplant parameters to 

operate the airplane or are required by 

the operating rules of this chapter, from 

inhibiting the primary display of flight 

or powerplant parameters needed by 

any flightcrew member in any normal 

mode of operation. Proposed § 23.1310 

would require these indication systems 

be designed and installed so 

information essential for continued safe 

flight and landing would be available to 

the flightcrew in a timely manner after 

any single failure or probable 

combination of failures. 

Proposed § 23.1310 would capture the 

safety intent of current §§ 23.1303, 

Flight and navigation instruments; 

23.1305, Powerplant instruments; 

23.1307, Miscellaneous equipment; 

23.1311, Electronic display instrument 

systems; 23.1321, Arrangement and 

visibility; 23.1323, Airspeed indicating 

system; 23.1331, Instruments using a 

power source; and 23.1337, Powerplant 

instruments installation. The current 

requirements can be traced to CAR 3, 

specifically, CAR 3.655, 3.661, 3.662, 

3.675, 3.663, 3.668, 3.670, 3.671, 3.672, 

3.673, and 3.674. These requirements, 

including § 23.1311, which did not have 

a corresponding rule in CAR 3, were 

based on the technology and design 

solutions available at the time of their 

adoption. Although these requirements 

are appropriate for traditional systems 

and designs found in airplanes designed 

to these assumptions, they lack the 

flexibility to adopt current and 

anticipated technologies and design 

capabilities. Furthermore, the FAA 

proposes to remove prescriptive 

requirements from the rule that 

historically provided standardization for 

primary flight instruments and controls. 

The FAA still believes this 

standardization is important for 

traditionally designed airplane 

instrumentation. Accordingly, to reduce 

the potential for pilot error, the reliance 

on standards accepted by the 

Administrator would maintain 

standardization for traditional systems. 

The proposed regulations would 

require applicants to use a means of 

compliance based on consensus 

standards or other means accepted by 

the Administrator. However, new 

technology is already being approved 

that does not meet the traditional 

installation requirements and guidance. 

At the same time, this technology is 

proving equivalent or better than the 

traditional technology.25 Furthermore, 

the FAA believes that new systems, 

displays, and controls have the potential 

to reduce pilot workload with a direct 

safety benefit. By removing prescriptive 

requirements for the rules and allowing 

alternatives, the industry would be able 

to develop and certify safety-enhancing 

technology faster. 

Proposed § 23.1310 would not require 

limitations that could not be exceeded 

due to system design or physical 

properties to be shown because they 

would be useless information and result 

in clutter of the displays. Additionally, 

the FAA proposes removing the 

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prescriptive design requirement in 

current § 23.1311 for the installation of 

secondary indicators. The safety intent 

is that a single failure or likely multiple 

failures would not result in the lack of 

all critical flight data. The design and 

installation of flight critical information 

should be such that the pilot could still 

fly partial panel after probable failures. 

The prescriptive redundancy 

requirements for installed secondary 

indicators have been too restrictive for 

airplanes limited to VFR operations. 

This has caused several applicants to 

request an ELOS finding from current 

§ 23.1311(a)(5). 

The safety intent of § 23.1311 is to 

provide crewmembers the ability to 

obtain the information necessary to 

operate the airplane safely in flight. 

Traditionally, the minimum was 

prescribed as airspeed, altimeter, and 

magnetic direction. The corresponding 

CAR 3 rule is 3.655. The regulation is 

redundant with the operating rules, 

specifically, §§ 91.205 and 135.149, as 

well as providing prescriptive design 

solutions that were assumed to achieve 

an acceptable level of safety. The 

prescriptive solutions precluded finding 

more effective or more economical paths 

to providing acceptable safety. Proposed 

§ 23.1310 would maintain the safety 

intent of the current rule. 

The FAA proposes consolidating the 

safety intent of current § 23.1305, 

Powerplant instruments, into proposed 

§ 23.1310, Flight, Navigation, and 

Powerplant Instruments. The safety 

intent of § 23.1305 is to provide 

crewmembers the ability to obtain the 

information necessary to operate the 

airplane and powerplant safely in flight. 

Traditionally, the minimum was 

prescribed, such as oil pressure, oil 

temperature, and oil quantity for all 

airplanes. The corresponding rules in 

CAR 3 are 3.655 and 3.675. Some of the 

regulation was redundant with the 

operating rules as well as providing 

prescriptive design solutions that were 

assumed to achieve an acceptable level 

of safety based on an assumption of 

powerplant types. The prescriptive 

solutions precluded finding more 

effective or more economical paths to 

providing acceptable safety. 

Additionally, they do not facilitate 

adoption of new technologies such as 

electric powered airplanes. The 

proposed § 23.1310, Flight, Navigation, 

and Powerplant Instruments, would 

maintain the safety intent of the current 

rule. 

iv. Proposed § 23.1315, Equipment, 

Systems, and Installation 

Proposed § 23.1315 would require an 

applicant to examine the design and 

installation of airplane systems and 

equipment, separately and in relation to 

other airplane systems and equipment, 

for any airplane system or equipment 

whose failure or abnormal operation has 

not been specifically addressed by 

another requirement in this part. 

Proposed § 23.1315 would require an 

applicant to determine if a failure of 

these systems and equipment would 

prevent continued safe flight and 

landing and if any other failure would 

significantly reduce the capability of the 

airplane or the ability of the flightcrew 

to cope with adverse operating 

conditions. Proposed § 23.1315 would 

require an applicant to design and 

install these systems and equipment, 

examined separately and in relation to 

other airplane systems and equipment, 

such that each catastrophic failure 

condition is extremely improbable, each 

hazardous failure condition is extremely 

remote, and each major failure 

condition was remote. Proposed 

§ 23.1315 would capture the safety 

intent found in portions of current 

§§ 23.691(g), Artificial stall barrier 

system; 23.729(f), Landing gear 

extension and retraction system; 

23.735(d), Brakes; 23.1309, Equipment, 

systems, and installations; 23.1323, 

Airspeed indicating system; 23.1325, 

Static pressure system; 23.1329, 

Automatic pilot system; 23.1331, 

Instruments using a power source; 

23.1337, Powerplant instruments 

installation; 23.1335, Flight director 

systems; 23.1353, Storage battery design 

and installation, 23.1357, Circuit 

protective devices; 23.1431, Electronic 

equipment; 23.1441(b), Oxygen 

equipment and supply; 23.1450(b), 

Chemical oxygen generators; 23.1451, 

Fire protection for oxygen equipment; 

and 23.1453, Protection of oxygen 

equipment from rupture. The current 

requirements can be traced to CAR 3, 

specifically, 3.652, 3.663, 3.665, 3.667, 

3.668, 3.670, 3.671, 3.672, 3.673, 3.674, 

and 3.683. The foundation of the current 

§ 23.1309 was derived from CAR 3.652, 

which stated that ‘‘each item of 

equipment, which is essential to the safe 

operation of the airplane, shall be found 

by the Administrator to perform 

adequately the functions for which it is 

to be used . . .’’. At that time, the 

airworthiness requirements were based 

on single-fault or fail-safe concepts. Due 

to the increased use of airplanes 

certificated under part 23 in the 1970s 

for all-weather operation, and a pilot’s 

increased reliance on installed avionic 

systems and equipment, § 23.1309, 

amendment 23–14 (38 FR 31816, 

November 19, 1973), was issued to 

provide an acceptable level of safety for 

such equipment, systems, and 

installations. Section 23.1309 

introduced two main concepts: multiple 

failure combinations as well as a single 

failure had to be considered and there 

must be an inverse relationship between 

the likelihood of occurrence and the 

severity of consequences. The premise 

was that more severe consequences 

should happen less often. 

In addition to specific part 23 design 

requirements, proposed § 23.1315 

requirements would apply to any 

equipment or system installed in the 

airplane. This proposed section 

addresses general requirements and is 

not intended to supersede any specific 

requirements contained in other part 23 

sections. Proposed § 23.1315 would not 

apply to the performance or flight 

characteristics requirements of subpart 

B, and structural loads and strength 

requirements of subpart C and D. 

However, it would apply to systems that 

complied with subpart B, C, D, and E 

requirements. As an example, proposed 

§ 23.1315 would not apply to an 

airplane’s inherent stall characteristics, 

but would apply to a stick pusher 

system installed to attain stall 

compliance. Both current § 23.1309 and 

proposed § 23.1315 rules are not 

intended to add requirements to specific 

rules in part 23, but to account for the 

added complexity of integration and 

new technologies. 

This proposed regulation would 

require an engineering safety analysis to 

identify possible failures, interactions, 

and consequences, and would require 

an inverse relationship between the 

probability of failures and the severity 

of consequences. This would be 

accomplished by requiring all of the 

airplane’s systems to be reviewed to 

determine if the airplane was dependent 

upon a system function for continued 

safe flight and landing and if a failure 

of any system on the airplane would 

significantly reduce the ability of the 

flightcrew to cope with the adverse 

operating condition. If the design of the 

airplane included systems that 

performed such functions, the systems 

would be required to meet standards 

that establish that maximum allowable 

probability of that failure. Section 

23.1315 would impose qualitative, 

rather than quantitative probabilities of 

occurrence. As the FAA determined 

which quantitative values satisfied the 

proposed performance standards, it 

would share that information in FAA 

guidance or documented means of 

compliance appropriate to the 

certification levels of proposed § 23.5. 

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v. Proposed § 23.1320, Electrical and 

Electronic System Lightning Protection 

Proposed § 23.1320 would require, for 

an airplane approved for IFR operations, 

that each electrical or electronic system 

that performed a function, the failure of 

which would prevent the continued safe 

flight and landing of the airplane, be 

designed and installed such that the 

airplane level function continues to 

perform during and after the time the 

airplane is exposed to lightning. 

Proposed § 23.1320 would also require 

these systems automatically recover 

normal operation of that function in a 

timely manner after the airplane is 

exposed to lightning, unless the 

system’s recovery conflicts with other 

operational or functional requirements 

of the system. 

Proposed § 23.1320 would require 

each electrical and electronic system 

that performed a function, the failure of 

which would reduce the capability of 

the airplane or the ability of the 

flightcrew to respond to an adverse 

operating condition, be designed and 

installed such that the function recovers 

normal operation in a timely manner 

after the airplane is exposed to 

lightning. 

Proposed § 23.1320 would capture the 

safety intent of current § 23.1306, 

Electrical and electronic system 

lightning protection. The original 

adoption of the rule, first introduced as 

part of § 23.1309, was justified because 

there was an increased use of small 

airplanes in all-weather operations with 

an increasing reliance on complex 

systems and equipment in the modern, 

complex, high-performance airplanes. 

The FAA wants to facilitate the use of 

systems in new airplanes that reduce 

pilot workload and enhance safety. The 

current requirement that all aircraft 

regardless of their design or operational 

limitations meet the same requirements 

for lightning regardless of the potential 

threat has been burdensome for the 

traditional VFR-only airplane designs. 

Proposed § 23.1320 would cover the 

airplanes with the greatest threat of 

lightning. In addition, the proposed 

language clarifies that the failure 

consequence of interest is at the 

airplane system level, which allows 

credit for design and installation 

architecture. 

vi. Proposed § 23.1325, High-Intensity 

Radiated Fields (HIRF) Protection 

Proposed § 23.1325 would require 

that electrical and electronic systems 

that perform a function whose failure 

would prevent the continued safe flight 

and landing of the airplane, be designed 

and installed such that the airplane 

level function is not adversely affected 

during and after the time the airplane is 

exposed to the HIRF environment. 

Proposed § 23.1325 would also require 

that these systems automatically recover 

normal operation of that function in a 

timely manner after the airplane is 

exposed to the HIRF environment, 

unless the system’s recovery conflicts 

with other operational or functional 

requirements of the system. Proposed 

§ 23.1325, High-Intensity Radiated 

Fields (HIRF) protection, would 

incorporate the safety intent of current 

§ 23.1308, High-intensity Radiated 

Fields (HIRF) protection. 

Before § 23.1308, amendment 23–57 

(72 FR 44016, August 6, 2007), the 

requirements for HIRF protection were 

found in § 23.1309. The adoption of 

§ 23.1308 was justified because there 

was an increased use of complex 

systems and equipment, including 

engine and flight controls, in small 

airplanes. These systems are more 

susceptible to the adverse effects of 

operation in the HIRF environment. 

The electromagnetic HIRF 

environment results from the 

transmission of electromagnetic energy 

from radar, radio, television, and other 

ground-based, ship-borne, or airborne 

radio frequency transmitters. The HIRF 

environment changes as the number and 

types of transmitters change. During the 

1990’s, extensive studies were 

conducted to define the environment 

that then existed. The FAA codified this 

environment in amendment 23–57 in 

appendix J to part 23—HIRF 

Environments and Equipment HIRF Test 

Levels. 

Proposed § 23.1325 would require the 

applicant to address the HIRF 

environment expected in service instead 

of solely relying on the HIRF 

environment codified in appendix J. 

The current appendix J to part 23 would 

become a means of compliance as the 

accepted expected HIRF environment, 

until other levels were accepted by the 

Administrator. This would allow the 

test levels to match the current threat as 

the environment changes over time. 

Additionally, the proposed language 

would clarify that the failure 

consequence of interest is at the 

airplane level, which allows credit for 

design and installation architecture. 

vii. Proposed § 23.1330, System Power 

Generation, Storage, and Distribution 

Proposed § 23.1330(a) would require 

that the power generation, storage, and 

distribution for any system be designed 

and installed to supply the power 

required for operation of connected 

loads during all likely operating 

conditions. Also, proposed § 23.1330(b) 

would require the design installation 

ensure no single failure or malfunction 

would prevent the system from 

supplying the essential loads required 

for continued safe flight and landing. 

Proposed § 23.1330 would also require 

the design and installation have enough 

capacity to supply essential loads, 

should the primary power source fail, 

for at least 30 minutes for airplanes 

certificated with a maximum altitude of 

25,000 feet or less, and at least 60 

minutes for airplanes certificated with a 

maximum altitude over 25,000 feet. 

Proposed § 23.1330 would capture the 

safety intent of the current §§ 23.1310, 

Power source capacity and distribution; 

23.1351, General; 23.1353, Storage 

battery design and installation; and 

23.1357, Circuit protective devices. The 

intent is to ensure airplane power 

generation and the related distribution 

systems are designed for adequate 

capacity and safe operation under 

anticipated use and in the event of a 

failure or malfunction. 

viii. Proposed § 23.1335, External and 

Cockpit Lighting 

Proposed § 23.1335 would require an 

applicant to design and install all lights 

to prevent adverse effects on the 

performance of flightcrew duties. 

Proposed § 23.1335 would require 

position and anti-collision lights, if 

installed, to have the intensities, flash 

rate, colors, fields of coverage, and other 

characteristics to provide sufficient time 

for another aircraft to avoid a collision. 

Proposed § 23.1335 would require 

position lights, if installed, to include a 

red light on the left side of the airplane, 

a green light on the right side of the 

airplane, spaced laterally as far apart as 

practicable, and a white light facing aft, 

located on an aft portion of the airplane 

or on the wing tips. 

Proposed § 23.1335 would require 

that an applicant design and install any 

taxi and landing lights, if required by 

operational rules, so they provide 

sufficient light for night operations. For 

seaplanes or amphibian airplanes, this 

section would also require riding lights 

to provide a white light visible in clear 

atmospheric conditions. Airplanes 

moored or maneuvering on water are by 

mairtime law considered watercraft; 

therefore, riding lights are required for 

seaplanes and amphibians during water 

operations. 

To encourage the installation of 

internal and external lighting systems 

with new safety enhancing technology 

and streamline the certification process, 

the FAA proposes removing most of the 

current prescriptive requirements and 

the detailed means of compliance for 

these requirements from current part 23. 

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The current prescriptive requirements 

would be replaced with performancebased requirements. The FAA expects 

that current means of compliance would 

continue to be used for the traditional 

airplane designs under part 23. 

Required lighting for the operation 

requested by an applicant would have to 

be installed and approved as part of the 

type design. The current rule requires 

that interior and exterior lighting 

function as intended without causing 

any safety hazard in normal operation. 

The proposed rule would require 

external lighting to make each airplane 

visible at night at a distance allowing 

each pilot to maneuver in sufficient 

time to avoid collision. The current rule 

specifies a specific amount of light 

illumination accounting for airframe 

obstructions. The FAA proposes 

removing this specified location and 

amount of illumination because it is 

more appropriate as means of 

compliance. The FAA does not consider 

small obstructions caused by airplane 

structure to be a safety issue. 

This section would capture the safety 

intent of current §§ 23.1381, Instrument 

lights, paragraph (c); 23.1383, Taxi and 

landing lights, paragraphs (a), (b) and 

(c); 23.1385, Position light system 

installation, paragraphs (a), (b) and (c); 

23.1387, Position light dihedral angles; 

23.1389, position light distribution and 

intensities; 23.1391, Minimum 

intensities in the horizontal plane of 

position lights; 23.1393, Minimum 

intensities in any vertical plane of 

position lights; 23.1395, Maximum 

intensities in overlapping beams of 

position lights; 23.1397, color 

specifications; 23.1399, Riding light; 

and 23.1401, Anticollision light system, 

paragraphs (a), (a)(1), (b), (c), (d), (e), 

and (f). 

ix. Proposed § 23.1400, Safety 

Equipment 

Proposed § 23.1400 would require 

safety and survival equipment, required 

by the operating rules of this chapter, to 

be reliable, readily accessible, easily 

identifiable, and clearly marked to 

identify its method of operation. 

The FAA proposes requirements for 

safety equipment needed for emergency 

landings and ditching when required by 

operational rules, and removal of the 

duplicative rules that are found in 

current part 23. Required safety 

equipment would have to be installed, 

located, and accessible for use in an 

emergency, and secured against 

emergency landing accelerations. The 

proposed rule would require safety, 

ditching, and survival equipment, be 

reachable, plainly marked for operation, 

and not be damaged in survivable 

emergency landings. 

This section would capture the safety 

intent of current §§ 23.1411, Safety 

equipment—General, paragraphs (a) and 

(b)(1); and 23.1415; Ditching equipment, 

paragraphs (a), (c), and (d). 

x. Proposed § 23.1405, Flight in Icing 

Conditions 

Proposed § 23.1405 would require an 

applicant to demonstrate its ice 

protection system would provide for 

safe operation, if certification for flight 

in icing conditions is requested. 

Proposed § 23.1405 would also require 

these airplanes to be protected from 

stalling when the autopilot is operating 

in a vertical mode. Proposed § 23.1405 

would require this demonstration be 

conducted in atmospheric icing 

conditions specified in part 1 of 

appendix C to part 25 of this chapter, 

and any additional icing conditions for 

which certification is requested. 

Proposed § 23.1405 would capture the 

safety intent of current § 23.775(a) 

Windshields and windows, and 

§ 23.1419, Ice protection. Proposed 

§ 23.1405 would also increase safety by 

adding icing conditions beyond those 

specified in the current § 23.1419. The 

proposed § 23.1405 would only apply to 

airplanes seeking certification for flight 

in icing. The current § 23.1419 only 

applies to airplanes seeking certification 

for flight in icing; however, ice 

protection systems can be certified 

without certification for flight in icing. 

The current ice protection system 

requirements in § 23.1419(a) would be 

captured in proposed § 23.1405(a)(1). 

The proposed rule would require an 

applicant to show systems are adequate 

in the icing conditions for which 

certification is requested. As in the 

current rule, ice protection systems 

would have to be shown to be adequate 

in the icing conditions of appendix C to 

part 25. Freezing drizzle and freezing 

rain icing conditions are optional icing 

conditions in which the airplane may be 

certificated to operate. These icing 

conditions, which the FAA added to 

appendix O to part 25 in amendment 

25–140, are not being defined in 

proposed § 23.230. The FAA determined 

that the definition of these optional 

icing conditions is more appropriate as 

a means of compliance. Ice crystal 

conditions are added to this proposal for 

certain air data probes to harmonize 

with EASA requirements. 

The Part 23 Icing ARC 

recommendations on activation and 

operation of ice protection systems 

would be used as a means of 

compliance to proposed § 23.1405(a)(1). 

This proposal would satisfy the intent of 

NTSB Safety Recommendations A–07– 

14 and A–07–15. 

Proposed § 23.1405(a)(2) is the Part 23 

Icing ARC recommendation for 

airplanes certified under part 23 in icing 

and is based on NTSB safety 

recommendation A–10–12. The target 

for this proposed rule is older airplanes 

adding an autopilot for first time, 

modifying certain autopilots on 

airplanes with a negative service history 

in icing, or significant changes that 

affect performance or flight 

characteristics. Proposed § 23.1405 

would require, under the changed 

product rule, to add proposed 

§ 23.1405(a)(2) to the certification basis 

without requiring the remainder of 

§ 23.1405 for certain autopilot 

modifications. For new airplanes, a stall 

warning system that complies with 

proposed § 23.230 would comply with 

proposed § 23.1405(a)(2). The vertical 

mode is a prescriptive requirement to 

limit the applicability. Simple 

autopilots such as a wing leveler would 

not be affected by this requirement. 

Numerous icing accidents have shown 

that unrecognized airspeed loss can 

occur with autopilots in altitude hold 

mode or vertical speed mode. 

Demonstration, as a means of 

compliance, may include design and/or 

analysis and does not mean natural 

icing flight tests are required. 

xi. Proposed § 23.1410, Pressurized 

System Elements 

Proposed § 23.1410 would require the 

minimum burst pressure of— 

• Hydraulic systems be at least 2.5 

times the design operating pressure with 

the proof pressure at least 1.5 times the 

maximum operating pressure; 

• Pressurization system elements be 

at least 2.0 times, and proof pressure be 

at least 1.5 times, the maximum normal 

operating pressure; and 

• Pneumatic system elements be at 

least 3.0 times, and proof pressure be at 

least 1.5 times, the maximum normal 

operating pressure. 

Additionally, this proposed section 

would also require that other 

pressurized system elements have 

pressure margins that take into account 

system design and operating conditions. 

This section would capture the safety 

intent of current §§ 23.1435, Hydraulic 

system, paragraphs (a)(4) and (b); 

23.1437, Accessories for multiengine 

airplanes; and 23.1438, Pressurization 

and pneumatic systems, paragraphs (a) 

and (b). 

xii. Proposed § 23.1457, Cockpit Voice 

Recorders 

The FAA is not proposing to revise 

current § 23.1457 because amendment 

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23–58 (73 FR 12542, March 7, 2008) and 

corrected on July 9, 2009 (74 FR 32799), 

was written to standardize the cockpit 

voice recorder rules to address the 

NTSB’s recommendations (70 FR 9752, 

February 28, 2005). The FAA agrees 

with NTSB recommendation numbers 

A–96–89, A–96–171, A–99–18, and 

parts of A–99–16 and A–99–17 and 

believes changing the current rule to 

remove prescriptive requirements could 

hinder the conduct of future accident 

investigations and be detrimental to 

aviation accident investigations. 

xiii. Proposed § 23.1459, Flight Data 

Recorders 

The FAA is not making any 

substantive changes to the current 

§ 23.1459 because amendment 23–58 

(73 FR 12541, March 7, 2008) was 

written to standardize the flight data 

recorder rules to address the NTSB’s 

recommendations. The FAA agrees with 

NTSB recommendation numbers A–96– 

89, A–96–171, A–99–18, and parts of 

numbers A–99–16 and A–99–17 and 

believes changing the current rule to 

remove prescriptive requirements could 

hinder the conduct of future accident 

investigations and be detrimental to 

aviation safety. Proposed 

§ 23.1459(a)(1), however, is amended to 

revise current references to §§ 23.1323, 

Airspeed indicating system; 23.1325, 

Static pressure system; and 23.1327, 

Magnetic direction indicator, as those 

sections are not contained in this 

NPRM. 

xiv. Current Subpart F Regulations 

Relocated to Other Proposed Subparts 

The requirement currently in 

§ 23.1419(a) to comply with subpart B 

requirements to show safe operating 

capability is moved to proposed 

§ 23.230 as recommended by the Part 23 

Icing ARC and Part 23 Reorganization 

ARC. 

Ice protection of engine inlets would 

move to proposed § 23.940, Powerplant 

ice protection. The Part 23 

Reorganization ARC had proposed that 

§ 23.1405 include these requirements, as 

well as heated pitot probe requirements 

for IFR airplanes. The FAA decided to 

separate them since compliance with 

proposed §§ 23.940 and 23.1300 would 

be required for all airplanes, whereas 

compliance with § 23.1405 would be 

optional. The FAA wants to avoid 

potential confusion on TCDS 

interpretation as to whether an airplane 

is certified for flight in icing. 

The requirements currently in 

§ 23.1381, Instrument lights, paragraphs 

(a) and (b) would be relocated to 

proposed § 23.1500, Flightcrew 

Interface. The requirements currently in 

§ 23.1411, Safety equipment—General, 

paragraph (b)(2) would be relocated to 

proposed § 23.600, Emergency 

conditions. 

xv. Removal of Subpart F of the Current 

Regulations 

When the FAA evaluated the current 

regulations, it determined that the 

prescriptive icing requirements in 

§§ 23.1323, Airspeed indicating system, 

and 23.1325, Static pressure system, 

would be means of compliance to 

proposed § 23.1405(a)(1). The current 

requirement for a heated pitot probe or 

an equivalent means on an IFR certified 

and a flight in icing conditions airplane 

in current § 23.1323(d) would become a 

means of compliance for proposed 

§ 23.1300. 

The part 23 re-write ARC had 

recommended that proposed § 23.1405 

include the requirement for a heated 

pitot probe on an IFR certified airplane, 

but the FAA determined this would be 

better addressed on a performance 

standard under proposed § 23.1300, 

because proposed § 23.1405 would only 

apply to icing certified airplanes. High 

altitude mixed phase and ice crystal 

conditions for certain high-performance 

airplanes, and ice protection 

requirements for stall warning and angle 

of attack would be means of 

compliance. The proposed standard 

would harmonize with EASA 

requirements. 

Current § 23.1416 would be removed 

since the requirements for proper 

inflation and annunciation of operation 

of pneumatic boots would be covered on 

a performance basis in proposed 

§§ 23.1300 and 23.1305. This would 

reflect that all types of ice protection 

systems have annunciation 

requirements, and would eliminate 

unnecessary annunciations. The Part 23 

Icing ARC recommended this approach. 

The analysis required in the current 

§ 23.1419(a), and all the requirements in 

the current § 23.1419(b) and (c), would 

become means of compliance to 

proposed 1405(a) and would be 

removed. 

Current § 23.1419(d) requires a means 

to detect critical ice accretions, 

including night lighting. The Part 23 

Icing ARC had proposed a new 

§ 23.1403 to replace these ice detection 

requirements, which would also address 

the SLD detection required by proposed 

§ 23.230. These ice detection 

requirements are more appropriately 

addressed as a means of compliance to 

accommodate new technology. For 

example, visual ice accretion detection 

as a means to activate ice protection 

systems is no longer necessary on some 

designs, examples being primary ice 

detection systems and icing conditions 

detection systems. However, there 

would remain a requirement for pilots 

to detect severe ice accretions, and this 

would be addressed in proposed 

§ 23.230(b). 

When the FAA evaluated the current 

regulations, it determined that the 

prescriptive requirements in §§ 23.1323, 

Airspeed indicating system; 23.1325, 

Static pressure system; 23.1327, 

Magnetic direction indicator; 23.1329, 

Automatic pilot system; 23.1335, Flight 

director systems; 23.1337, Powerplant 

instruments installation; 23.1353, 

Storage battery design and installation; 

and 23.1357, Circuit protective devices, 

would be covered on a performance 

basis by proposed §§ 23.1300; 23.1305; 

23.1310; and 23.1315. 

Current § 23.1401, Anticollision light 

system, paragraph (a)(2) would be 

removed as introductory material. 

Current § 23.1415, ditching equipment, 

paragraph (b) would be removed but 

could serve as a means of compliance. 

The current §§ 23.1435, Hydraulic 

systems, paragraphs, (a), (a)(1), (a)(2), 

(a)(3), and (c); 23.1438, Pressurization 

and pneumatic systems, paragraph (c), 

would be removed as prescriptive 

design and means of compliance. 

Current § 23.1443, Minimum mass flow 

of supplemental oxygen, paragraph (d) 

would be removed as a definition. 

Current § 23.1445, paragraph (e) would 

be removed as redundant to current 

§ 91.211, paragraph (a)(3). 

7. Subpart G—Flightcrew Interface and 

Other Information 

a. General Discussion 

The FAA proposes to expand subpart 

G to address not only current operating 

limitations and information, but also the 

concept of flightcrew interface. Based 

on current technologies, the FAA 

anticipates that new airplanes will 

heavily rely on automation and systems 

that require new and novel pilot or 

flightcrew interface. The FAA is 

proposing to address the pilot interface 

issues found in subparts D and F with 

proposed § 23.1500. Otherwise, subpart 

G retains the safety requirements from 

the current rules without change. Refer 

to appendix 1 of this preamble for a 

cross-reference table detailing how the 

current regulations are addressed in the 

proposed part 23 regulations. 

b. Specific Discussion of Changes 

i. Proposed § 23.1500, Flightcrew 

Interface 

Proposed § 23.1500 would require the 

pilot compartment and its equipment to 

allow the pilot(s) to perform their 

duties, including taxi, takeoff, climb, 

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26See www.regulations.gov (Docket #FAA–2015– 

1621). 

cruise, descent, approach, and landing; 

and perform any maneuvers within the 

operating envelope of the airplane, 

without excessive concentration, skill, 

alertness, or fatigue. Proposed § 23.1500 

would also require an applicant to 

install flight, navigation, surveillance, 

and powerplant controls and displays so 

qualified flightcrew could monitor and 

perform all tasks associated with the 

intended functions of systems and 

equipment in order to make the 

possibility that a flightcrew error could 

result in a catastrophic event highly 

unlikely. Proposed § 23.1500 would 

capture the safety intent of current part 

23 rules that are directly related to the 

pilot or flightcrew interface with the 

airplane. Interfaces include controls, 

displays, and visibility requirements. 

Current and anticipated technologies 

that affect how the pilot interfaces with 

the airplane are expected to expand 

faster than other technologies. The FAA 

believes that significant safety 

improvements can result from the 

evolution of how the pilot interfaces 

with the airplane. Pilot workload is a 

major factor in causing accidents, but it 

is almost impossible to connect 

workload-related mistakes to an 

accident after the accident has 

happened. Evidence from large airplane 

accidents, where we have recorded data 

as well as research, points to the 

importance of the pilot interface and 

associated mistakes as causal factors in 

aircraft accidents. The smart use of 

automation and phase-of-flight-based 

displays could reduce pilot workload 

and increase pilot awareness. 

The converse is also true. Equipment 

is becoming available faster than 

manufacturers and the FAA can 

evaluate it. Determining the safety risks 

and recognizing the safety benefits of 

new technology available to the pilot is 

important. For this reason, the proposed 

language addresses the safety issues of 

the current §§ 23.699, Wing flap 

position indicator; 23.745 Nose/Tail 

wheel steering, 23.1303, Flight and 

navigation instruments, paragraph 

(g)(3); 23.1321, Arrangement and 

visibility, paragraphs (a),(b),(d), and (e); 

23.1311, Electronic display instrument 

systems, paragraphs (a)(6) and (7); 

23.771, Pilot compartment, paragraph 

(a), 23.773(a) Pilot compartment view, 

23.777, Cockpit controls; 23.779, Motion 

and effect of cockpit controls; and 

23.781, Cockpit control knob shape; are 

addressed in proposed § 23.1500(a) and 

(b). The proposed language would allow 

the FAA to rapidly evaluate new 

equipment for concentration, skill, 

alertness, and fatigue against pilot 

workload as is current practice. More 

importantly, the FAA would remove the 

prescriptive requirements from the 

current rules to allow for alternative 

approaches to pilot interface that would 

reduce pilot workload or increase safety. 

ii. Proposed § 23.1505, Instrument 

Markings, Control Markings, and 

Placards 

Proposed § 23.1505 would require 

each airplane to display in a 

conspicuous manner any placard and 

instrument marking necessary for 

operation. Proposed § 23.1505 would 

also require an applicant to clearly mark 

each cockpit control, other than primary 

flight controls, as to its function and 

method of operation and include 

instrument marking and placard 

information in the AFM. The 

consolidation of these sections appears 

large, but many of these sections contain 

one prescriptive requirement that, in 

many cases, is based on traditional 

airplanes, instruments, and equipment. 

iii. Proposed § 23.1510, Airplane Flight 

Manual 

Proposed § 23.1510 would require an 

applicant to furnish an AFM with each 

airplane that contains the operating 

limitations and procedures, 

performance information, loading 

information, and any other information 

necessary for the operation of the 

airplane. 

The proposed rules capture the 

prescriptive list of information that is 

considered necessary for the operation 

of the traditional airplanes. The current 

rules contain very prescriptive and 

detailed information. Furthermore, that 

level of detail assumes a traditional 

airplane configuration and operation. 

The FAA proposes to remove this detail 

from the rule because it is more 

appropriate as means of compliance. 

Currently, the majority of airplanes 

certificated under part 23 already use an 

industry standard to develop their 

AFMs—General Aviation Manufactures 

Association Specification 1, 

Specification for Pilot’s Operating 

Handbook.26 The FAA already accepts 

this industry standard for many 

airplanes certificated under part 23 

because it includes the information that 

is currently required in part 23. The 

FAA believes that allowing alternative 

approaches to information would 

facilitate new technology integration 

into airplanes certified under part 23. 

The proposed § 23.1510(d) would 

capture the safety intent of the current 

§§ 23.1505, Airspeed limitations, thru 

23.1527, Maximum operating altitude, 

specific to operating limitations and 

other limitations and information 

necessary for safe operation. 

iv. Proposed § 23.1515, Instructions for 

Continued Airworthiness 

Proposed § 23.1515 would require an 

applicant to prepare Instructions for 

Continued Airworthiness in accordance 

with proposed appendix A to this part, 

that are acceptable to the Administrator, 

prior to the delivery of the first airplane 

or issuance of a standard certification of 

airworthiness, whichever occurs later. 

This proposed section would capture 

the current § 23.1529 without change. 

The FAA proposes renaming Appendix 

G to Part 23—Instructions for Continued 

Airworthiness, to Appendix A to Part 

23—Instructions for Continued 

Airworthiness. 

8. Appendices to Part 23 

a. General Discussion 

Many of the appendices to part 23 

contain information that the FAA 

believes would be more appropriate as 

a means of compliance, with the 

exception of Appendix G to Part 23– 

Instructions for Continued 

Airworthiness. Appendices A, B, C, D, 

E, F, H, and J would be removed and 

appendix G would be renamed 

Appendix A—Instructions for 

Continued Airworthiness. 

b. Specific Discussion of Changes 

i. Proposed Appendix A to Part 23— 

Instructions for Continued 

Airworthiness 

The FAA proposes renaming 

Appendix G to Part 23—Instructions for 

Continued Airworthiness, as Appendix 

A to Part 23—Instructions for Continued 

Airworthiness. 

ii. Removal of Appendices to Part 23 

Appendix A to Part 23—Simplified 

Design Load Criteria. The FAA proposes 

to remove this appendix because the 

content is more appropriate for 

inclusion in methods of compliance. 

Appendix B to Part 23—[Reserved]. 

The FAA proposes to remove this 

appendix because it has been reserved 

since amendment 23–42. There is no 

reason to include this appendix in the 

proposed revision to part 23. 

Appendix C to Part 23—Basic 

Landing Conditions. The FAA proposes 

to remove this appendix because the 

content is more appropriate for 

inclusion in methods of compliance. 

Appendix D to Part 23—Wheel SpinUp and Spring-Back Loads. The FAA 

proposes to remove this appendix 

because the content is more appropriate 

for inclusion in methods of compliance. 

Appendix E to Part 23—[Reserved]. 

The FAA proposes to remove this 

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appendix because the current appendix 

is reserved and contains no information. 

Appendix F to Part 23—Test 

Procedure. The FAA proposes to remove 

this appendix because this is purely a 

means of showing compliance for 

materials that must comply with selfextinguishing flammability 

requirements. 

Appendix H to Part 23—Installation 

of an Automatic Power Reserve (APR) 

System. The FAA proposes to remove 

this appendix because the FAA believes 

that the detailed and prescriptive 

language of appendix H is more 

appropriate as means of compliance. 

Appendix I to Part 23—Seaplane 

Loads. The FAA proposes to remove 

this appendix because the content is 

more appropriate for inclusion in 

methods of compliance. 

Appendix J to Part 23—HIRF 

Environments and Equipment HIRF Test 

Levels. The accepted HIRF environment 

is codified as appendix J to part 23— 

HIRF Environments and Equipment 

HIRF Test Levels. The proposed 

language in § 23.1325 would revise this 

to the expected HIRF environment. The 

current appendix J to part 23 would 

remain an accepted expected HIRF 

environment until the Administrator 

accepted other levels. Any new 

expected HIRF environment would be 

found in FAA guidance material or 

other standards accepted by the 

Administrator. This would allow the 

certification requirement to match the 

current threat agreed to over time. 

Additionally, the proposed language 

would clarify that the failure 

consequence of interest is at the 

airplane level, which allows credit for 

design and installation architecture. 

B. Miscellaneous Amendments (§§ 21.9, 

21.17, 21.24, 21.35, 21.50, 21.101, 35.1, 

35.37, 91.205, 91.313, 91.323, 91.531, 

121.310, 135.169, and Appendix E to 

Part 43) 

1. Production of Replacement and 

Modification Articles (§ 21.9) 

The FAA proposes amending § 21.9 

by adding paragraph (a)(7) to provide 

applicants with an alternative method to 

obtain FAA approval to produce 

replacement and modification articles 

that are reasonably likely to be installed 

on type certificated aircraft. We also 

propose to revise paragraphs (b) and (c) 

to specify these articles would be 

suitable for use in a type certificated 

product. These proposed changes would 

allow an applicant to submit production 

information for a specific article, but 

would not require the producer of the 

article to apply for approval of the 

article’s design or obtain approval of its 

quality system. Accordingly, approval to 

produce a modification or replacement 

article under proposed § 21.9(a)(7) 

would not constitute a production 

approval as defined in § 21.1(b)(6). The 

FAA intends to limit use of this 

procedure to articles whose improper 

operation or failure would not cause a 

hazard. Approval would be granted to 

the applicant on a case-by-case basis, 

specific to the installation proposed, 

accounting for potential risk and 

considering the safety continuum. 

2. Designation of Applicable 

Regulations (§ 21.17) 

The FAA proposes amending § 21.17, 

by removing the reference to § 23.2, 

because this section would be deleted. 

The requirements in § 23.2 are currently 

addressed in the operational rules. 

Since § 23.2 is a retroactive rule, it is 

appropriate for the requirement to be in 

the operating rules. As a result, the FAA 

also proposes amending § 91.205 by 

revising paragraphs (b)(13) and (b)(14) 

to ensure removing this requirement 

would not have any effect on the 

existing fleet. 

3. Issuance of Type Certificate: Primary 

Category Aircraft (§ 21.24) 

The FAA proposes amending § 21.24 

by revising paragraph (a)(1)(i) to modify 

the phrase as defined by § 23.49 to 

include reference to amendment 23–62 

(76 FR 75736, December 2,2011), 

effective on January 31, 2012. This 

revision is necessary to maintain a 

complete definition of stall speed in this 

section, as the current § 23.49 would be 

removed from the proposed rule. 

4. Flight Tests (§ 21.35) 

The FAA proposes amending § 21.35 

by revising paragraph (b)(2) to delete the 

reference to reciprocating engines and 

expanding the exempted airplanes to 

include all low-speed part 23 airplanes 

6,000 pounds or less. This proposed 

change would align the requirements for 

function and reliability testing with the 

proposed changes in part 23 that do not 

distinguish between propulsion types. 

This change would allow the FAA 

flexibility to address new propulsion 

types based on the changes to part 23. 

5. Instructions for Continued 

Airworthiness and Manufacturer’s 

Maintenance Manuals Having 

Airworthiness Limitations Sections 

(§ 21.50) 

The FAA proposes amending 

§ 21.50(b) to reference § 23.1515 rather 

than § 23.1529. This change is editorial 

and would align with the proposed part 

23 numbering convention. 

6. Designation of Applicable 

Regulations (§ 21.101) 

The FAA proposes amending § 21.101 

by removing the reference to § 23.2 as 

this section is proposed to be deleted 

and is addressed in the operating rules, 

and to refer to the proposed part 23 

certification levels in paragraph (c). The 

current 6,000-pound reference would be 

augmented by the inclusion of simple 

airplanes, certification level 1 low-speed 

airplanes, and certification level 2 lowspeed airplanes, in order to align the 

current rules with the proposed part 23 

certification levels. 

Additionally, the FAA recognizes that 

it may be impractical for airplanes 

certified under part 23, amendment 23– 

62, or prior amendments, to move up to 

the latest amendment for modifications. 

Section 21.101 would not be revised to 

address this circumstance, as this 

section allows for certification at a 

lower amendment level if meeting the 

current amendment is impractical. This 

current provision would allow for 

compliance to the certification 

requirements at amendment 23–62 or 

earlier when compliance to the latest 

amendment of part 23 was determined 

by the FAA to be impractical. 

7. Applicability (§ 35.1) 

The FAA proposes amending § 35.1 

by replacing the reference to § 23.907 

with proposed § 23.905(c). 

8. Fatigue Limits and Evaluation 

(§ 35.37) 

The FAA proposes amending § 35.37 

by replacing the reference to § 23.907 

with proposed § 23.905(c). 

9. Altimeter System Test and Inspection 

(Appendix E to Part 43) 

The FAA proposes amending 

appendix E to part 43 by revising 

paragraph (a)(2) to conform with 

proposed part 23 changes. This 

proposed change would affect owners 

and operators of part 23 certificated 

airplanes in controlled airspace under 

instrument flight rules who must 

comply with § 91.411. Concurrent with 

this rule change, AC 43–6, Altitude 

Reporting Equipment and Transponder 

System Maintenance and Inspection 

Practices, would be revised to include a 

static pressure system proof test 

acceptable to the Administrator. 

Additionally, while reviewing appendix 

E to part 43, paragraph (a)(2), we noted 

that it remains silent on parts 27 and 29 

rotorcraft and Civil Air Regulations 

certificated aircraft. The static pressure 

system proof test in AC 43–6 ensures 

the accuracy needed to meet § 91.411 

requirements. 

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10. Powered Civil Aircraft With 

Standard Category U.S. Airworthiness 

Certificates: Instrument and Equipment 

Requirements (§ 91.205) 

The FAA proposes amending § 91.205 

by revising paragraphs (b)(13) and 

(b)(14) to include the potential for 

allowing other approved restraint 

systems. Additionally, paragraph (b)(14) 

refers to § 23.561(b)(2), which would be 

retitled in the proposed revision for 

structural strength limits and would be 

addressed in the means of compliance. 

Section 91.205(b)(16) would be deleted 

and incorporated into (b)(14) with no 

additional requirements. The part 23 

proposal would delete references to 

utility and acrobatic categories, as they 

would be incorporated into the normal 

categories that would be redefined into 

performance-based standards. 

11. Restricted Category Civil Aircraft: 

Operating Limitations (§ 91.313) 

The FAA proposes amending 

§ 91.313(g) to include the potential for 

allowing other approved restraint 

systems. Additionally, paragraph (g) 

includes a regulatory reference to 

§ 23.561(b)(2), which would be retitled 

in the proposed revision as § 23.600, 

which would be accompanied by 

accepted means of compliance. 

Approval for a shoulder harness or 

restraint system, therefore, would 

require withstanding the static inertia 

loads specified in § 23.600 during 

emergency conditions. 

12. Increased Maximum Certification 

Weights for Certain Airplanes Operated 

in Alaska (§ 91.323) 

The FAA proposes amending § 91.323 

by removing reference to § 23.337 

because this section would be revised 

and consolidated with other structural 

requirements. The relevant prescriptive 

requirement(s) maneuvering load factors 

found in § 23.337 would be added to the 

regulation in § 91.323(b)(3). 

13. Second in Command Requirements 

(§ 91.531) 

The FAA proposes amending 

§ 91.531(1) and (3) to incorporate the 

new risk and performance levels 

proposed in this NPRM. The FAA 

proposes deleting the reference to 

utility, acrobatic, and commuter 

categories in part 23. Other divisions 

would be used to define levels of 

certification for normal category 

airplanes. This proposed amendment 

would ensure airplanes certificated in 

the commuter category in the past and 

airplanes certificated in the future under 

the proposed part 23 airworthiness and 

performance levels would be addressed 

in this rule. 

14. Additional Emergency Equipment 

(§ 121.310) 

The FAA proposes amending 

§ 121.310(b)(2)(iii) to reflect the 

reference to § 23.811(b), effective June 

16, 1994. This would be an update to 

the reference for conformity only. This 

amendment would make no change to 

the requirements of the rule. 

15. Additional Airworthiness 

Requirements (§ 135.169) 

The FAA proposes amending 

§ 135.169(b) by deleting the terms, 

‘‘reciprocating-engine or turbopropellerpowered’’. The current rule limits 

operation under this part to 

reciprocating-engine or turbopropellerpowered small airplanes. By amending 

the paragraph as proposed, other small 

airplanes, regardless of propulsion type 

and including turbojet-powered, would 

potentially be considered for 

certification under this part. 

The FAA also proposes to allow a 

small airplane in normal category, in 

§ 135.169(b)(8), to operate within the 

rules governing commuter and on 

demand operations. This action would 

be necessary as a result of the proposed 

part 23 rules which would sunset the 

commuter category for newly type 

certificated airplanes and create a 

normal category, certification level 4 

airplane as equivalent to the commuter 

category by applying to 10–19 

passengers. This proposed amendment 

would allow for the consideration of the 

new category airplane and to ensure a 

continued higher level of safety for 

commercial operations. Because of the 

ground-breaking nature of the part 23 

proposals, the associated adjustment to 

performance-based airworthiness 

standards in future airplane designs and 

manufacturing, and the myriad of 

potential possibilities for attaining a 

means of compliance for airplane type 

certification, the FAA proposes to 

require the new normal category 

certification level 4 airplanes to meet 

the current airworthiness and 

performance standards of the commuter 

category found in part 23 thru 

amendment 23–62. These standards are 

envisioned to remain as requirements 

for the new normal category 

certification level 4 airplanes into the 

near-term future, but not the long-term. 

It is intended that once the new part 23 

requirements have proven successful 

with the new normal category 

certification levels 1, 2, and 3 airplanes, 

the FAA would reconsider normal 

category certification level 4 airplanes 

for part 135 commercial operations. 

VII. Regulatory Notices and Analyses 

A. Regulatory Evaluation Summary 

Changes to Federal regulations must 

undergo several economic analyses. 

First, Executive Order 12866 and 

Executive Order 13563 direct that each 

Federal agency shall propose or adopt a 

regulation only upon a reasoned 

determination that the benefits of the 

intended regulation justify its costs. 

Second, the Regulatory Flexibility Act 

of 1980 (Pub. L. 96–354) requires 

agencies to analyze the economic 

impact of regulatory changes on small 

entities. Third, the Trade Agreements 

Act (Pub. L. 96–39) prohibits agencies 

from setting standards that create 

unnecessary obstacles to the foreign 

commerce of the United States. In 

developing U.S. standards, this Trade 

Act requires agencies to consider 

international standards and, where 

appropriate, that they be the basis of 

U.S. standards. Fourth, the Unfunded 

Mandates Reform Act of 1995 (Pub. L. 

104–4) requires agencies to prepare a 

written assessment of the costs, benefits, 

and other effects of proposed or final 

rules that include a Federal mandate 

likely to result in the expenditure by 

State, local, or tribal governments, in the 

aggregate, or by the private sector, of 

$100 million or more annually (adjusted 

for inflation with base year of 1995). 

This portion of the preamble 

summarizes the FAA’s analysis of the 

economic impacts of this proposed rule. 

We suggest readers seeking greater 

detail read the full regulatory 

evaluation, a copy of which we have 

placed in the docket for this rulemaking. 

In conducting these analyses, FAA 

has determined that this proposed rule: 

(1) Would have benefits that justify its 

costs, (2) would not be an an 

economically ‘‘significant regulatory 

action’’ as defined in section 3(f) of 

Executive Order 12866, (3) would be 

‘‘significant’’ as defined in DOT’s 

Regulatory Policies and Procedures; (4) 

would have a significant positive 

economic impact on small entities; (5) 

would not create unnecessary obstacles 

to the foreign commerce of the United 

States; and (6) would not impose an 

unfunded mandate on state, local, or 

tribal governments, or on the private 

sector by exceeding the threshold 

identified above. These analyses are 

summarized below. 

1. Total Benefits and Costs of This Rule 

The following table shows the 

estimated benefits and costs of the 

proposed rule. The major factors driving 

the expected costs of this proposal are 

the additional training tasks, database 

development, and documentation to 

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27On January 30, 2014, the DOT published a 

memo on ‘‘Estimating Total Costs of Compensation 

Based on Wage Rates or Salaries.’’ The memo 

directs the FAA that when a rule requires 

incremental hours per existing employee, the wage/ 

salary multiplier is of smaller magnitude because 

not all categories of employer provided benefits 

increase with additional hours worked by an 

individual employee. 

FAA and industry part 23 certification 

engineers. Benefits consist of safety 

benefits from preventing stall and spin 

accidents and savings from reducing the 

number of special conditions, 

exemptions, and equivalent levels of 

safety. If the proposed rule saves only 

one human life by improving stall 

characteristics and stall warnings, that 

alone would result in benefits 

outweighing the costs. 

ESTIMATED BENEFITS AND COSTS FROM 2017 TO 2036 

[2014 $ Millions] 

Costs Safety benefits + cost savings = total benefits 

Total ............................................................................................ $3.9 $19.6 + $12.6 = $32.2. 

Present value .............................................................................. $3.9 $6.2 + $5.8 = $12.0. 

2. Who is potentially affected by this 

rule? 

The proposal would affect U.S. 

manufacturers and operators of new part 

23 type certificated airplanes. 

3. Assumptions 

The benefit and cost analysis for the 

regulatory evaluation is based on the 

following factors/assumptions: 

• The analysis is conducted in constant 

dollars with 2014 as the base year. 

• The final rule would be effective in 2017. 

• The primary analysis period for costs 

and benefits extends for 20 years, from 2017 

through 2036. This period was selected 

because annual costs and benefits will have 

reached a steady state by 2036. 

• Future part 23 type certifications and 

deliveries are estimated from historical part 

23 type certifications and deliveries. 

• Costs for the new part 23 type 

certifications forecasted in the ‘‘Fleet 

Discussion’’ section of the regulatory 

evaluation would occur in year 1 of the 

analysis interval. 

• Airplane deliveries from the forecasted 

part 23 type certificates would start in year 

5 of the analysis interval. 

• The FAA uses a seven percent discount 

rate for the benefits and costs as prescribed 

by OMB in Circular A–4. 

• The baseline for estimating the costs and 

benefits of the proposed rule would be part 

23, through amendment 62. 

• The FAA estimates 335 FAA part 23 

certification engineers would require 

additional training as a result of this 

proposal. The FAA assumes that the same 

number of industry part 23 certification 

engineers would also require additional 

training as a result of this proposal. 

• The FAA estimates that this proposal 

would add 16 hours of training to FAA and 

industry part 23 certification engineers. 

• Since this training program would be online, we estimate no travel costs for the 

engineers. 

• FAA pay-band tables and the Bureau of 

Labor Statistics (BLS) determine the hourly 

wages used to estimate the costs to the FAA 

and applicants. 

• Using the U.S. Department of 

Transportation guidance, the wage multiplier 

for employee benefits is 1.17.27

4. Benefits of This Rule 

The major safety benefit of this 

proposed rule is to add stall 

characteristics and stall warnings that 

would result in airplane designs that are 

more resistant to depart controlled flight 

inadvertently. The largest number of 

accidents for small airplanes is a stall or 

departure-based LOC in flight. This 

proposal would also have cost savings 

by streamlining the certification process 

and encouraging new and innovative 

technology. Streamlining the 

certification process would reduce the 

issuance of special conditions, 

exemptions, and equivalent level of 

safety findings. 

5. Costs of This Rule 

The proposed rules major costs are 

the engineer training costs and the 

certification database creation costs. 

Additional costs would also accrue from 

the proposed controllability and stall 

sections that would increase scope over 

current requirements and manual 

upgrade costs. 

In the following table, we summarize 

the total estimated compliance costs by 

category. The FAA notes that since we 

assumed that all costs occurred in Year 

1 of the analysis interval, the 2014- 

dollar costs equal the present value 

costs. 

TOTAL COST SUMMARY BY CATEGORY

Type of cost 

Total costs 

(2014$) and 

P.V. 

§ 23.200 Controllability ......... $276,939 

§ 23.215 Stall characteristics, 

stall warning, and spins .... 500,000 

Engineer Training Costs ....... 1,149,418 

Certification Database Costs 1,293,750 

Manual Upgrade Costs ......... 700,000 

TOTAL COST SUMMARY BY

CATEGORY—Continued 

Type of cost 

Total costs 

(2014$) and 

P.V. 

Total Costs .................... 3,920,106 

* These numbers are subject to rounding 

error. 

B. Initial Regulatory Flexibility 

Determination 

The Regulatory Flexibility Act of 1980 

(Pub. L. 96–354) (RFA) establishes ‘‘as a 

principle of regulatory issuance that 

agencies shall endeavor, consistent with 

the objectives of the rule and of 

applicable statutes, to fit regulatory and 

informational requirements to the scale 

of the businesses, organizations, and 

governmental jurisdictions subject to 

regulation. To achieve this principle, 

agencies are required to solicit and 

consider flexible regulatory proposals 

and to explain the rationale for their 

actions to assure that such proposals are 

given serious consideration.’’ The RFA 

covers a wide-range of small entities, 

including small businesses, not-forprofit organizations, and small 

governmental jurisdictions. 

Agencies must perform a review to 

determine whether a rule will have a 

significant economic impact on a 

substantial number of small entities. If 

the agency determines that it will, the 

agency must prepare a regulatory 

flexibility analysis as described in the 

RFA. 

The FAA believes that this proposed 

rule could have a significant economic 

impact on a substantial number of 

entities because we believe that this rule 

could enable the creation of new part 23 

type certificates and new manufacturers. 

The FAA has been working with U.S. 

and foreign small aircraft manufacturers 

since 2007 to review the life cycle of 

part 23 airplanes and determine what 

needed improvement. 

The purpose of this analysis is to 

provide the reasoning underlying the 

FAA determination. 

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28 13 CFR 121.201, Size Standards Used to Define 

Small Business Concerns, Sector 48–49 

Transportation, Subsector 481 Air Transportation. 

Under Section 603(b) of the RFA, the 

initial analysis must address: 

• Description of reasons the agency is 

considering the action; 

• Statement of the legal basis and 

objectives for the proposed rule; 

• Description of the record keeping and 

other compliance requirements of the 

proposed rule; 

• All federal rules that may duplicate, 

overlap, or conflict with the proposed rule; 

• Description and an estimated number of 

small entities to which the proposed rule will 

apply; and 

• Describe alternatives considered. 

1. Reasons Why the Rule Is Being 

Proposed 

The FAA proposes this action to 

amend the airworthiness standards for 

new part 23 type certificated airplanes 

to reflect the current needs of the small 

airplane industry, accommodate future 

trends, address emerging technologies, 

and enable the creation of new part 23 

manufacturers and new type certificated 

airplanes. The proposed changes to part 

23 are necessary to eliminate the current 

workload of exemptions, special 

conditions, and equivalent levels of 

safety findings necessary to certificate 

new part 23 airplanes. These proposed 

part 23 changes would also promote 

safety by enacting new regulations for 

controllability and stall standards and 

promote new technologies in part 23 

airplanes. 

2. Statement of the Legal Basis and 

Objectives 

The FAMRA required the 

Administrator, in consultation with the 

aviation industry, to assess the aircraft 

certification and approval process. In 

addition, the SARA directs the FAA to 

create performance-based regulations for 

small airplanes and provide for the use 

of industry developed consensus 

standards to allow flexibility in the 

certification of new technology. 

Accordingly, this proposed rule 

would amend Title 14 of the Code of 

Federal Regulations to revise the 

airworthiness standards for small 

airplanes by removing current 

prescriptive design requirements and 

replacing those requirements with risk 

and performance-based airworthiness 

standards. 

The FAA’s authority to issue rules on 

aviation safety is found in Title 49 of the 

United States Code. Subtitle I, Section 

106 describes the authority of the FAA 

Administrator. Subtitle VII, Aviation 

Programs, describes in more detail the 

scope of the agency’s authority. This 

rulemaking is promulgated under the 

authority described in Subtitle VII, Part 

A, Subpart III, Section 44701. Under 

that section, the FAA is charged with 

promoting safe flight of civil airplanes 

in air commerce by prescribing 

minimum standards required in the 

interest of safety for the design and 

performance of airplanes. This 

regulation is within the scope of that 

authority because it prescribes new 

performance-based safety standards for 

the design of normal category airplanes. 

3. Projected Reporting, Recordkeeping 

and Other Requirements 

The FAA expects no more than 

minimal new reporting and 

recordkeeping compliant requirements 

would result from this proposed rule 

because the prescriptive nature of part 

23 would be in other FAA approved 

documents where future technology can 

readily be adopted into the regulatory 

framework. The FAA requests comment 

regarding the anticipated reduction in 

paperwork and recordkeeping burdens 

that may result from this revision. 

4. Overlapping, Duplicative, or 

Conflicting Federal Rules 

The proposed rule would not overlap, 

duplicate, or conflict with existing 

federal rules. 

5. Estimated Number of Small Firms 

Potentially Impacted 

Under the RFA, the FAA must 

determine whether a proposed or final 

rule significantly affects a substantial 

number of small entities. This 

determination is typically based on 

small entity size and cost thresholds 

that vary depending on the affected 

industry. Using the size standards from 

the Small Business Administration for 

Air Transportation and Aircraft 

Manufacturing, we defined companies 

as small entities if they have fewer than 

1,500 employees.28

There are seven U.S. owned aircraft 

manufacturers who delivered part 23 

airplanes in the 1998–2013 analysis 

interval. These manufacturers are 

Adam, American Champion, Cessna, 

Hawker Beechcraft, Maule, Quest, and 

Sino-Swearingen. 

Using information provided by the 

Internet filings and news reports, 

manufacturers that are subsidiary 

businesses of larger businesses, 

manufacturers that are foreign owned, 

and businesses with more than 1,500 

employees were eliminated from the list 

of small entities. Cessna and Hawker 

Beechcraft are businesses with more 

than 1,500 employees. For the 

remaining businesses, we obtained 

company revenue and employment from 

the above sources. 

The base year for the final rule is 

2014. Although the FAA forecasts traffic 

and air carrier fleets, we cannot 

determine either the number of new 

entrants or who will be in the part 23 

airplane manufacturing business in the 

future. Therefore, we use current U.S. 

part 23 airplane manufacturers’ revenue 

and employment in order to determine 

the number of small entities this 

proposed rule would affect. 

The methodology discussed above 

resulted in the following list of five U.S. 

part 23 airplane manufacturers, with 

less than 1,500 employees. 

Manufacturer Number of 

employees 

Annual 

revenue 

Part 23 Manufacturer 1 ............................................................................................................................................ 2 $110,000 

Part 23 Manufacturer 2 ............................................................................................................................................ 65 7,000,000 

Part 23 Manufacturer 3 ............................................................................................................................................ 75 35,000,000 

Part 23 Manufacturer 4 ............................................................................................................................................ 175 34,000,000 

Part 23 Manufacturer 5 ............................................................................................................................................ 2 97,000 

From this list of small entity U.S. 

airplane manufacturers, there are three 

manufacturers currently producing part 

23 reciprocating engine airplanes; only 

one manufacturer producing turboprops 

and only one producing turbojets. The 

single manufacturer producing a part 23 

turbojet has not delivered an airplane 

since 2009 and is still working on 

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acquiring the means to start up its 

production line again. One of the 

manufacturers producing a part 23 

reciprocating engine airplane has not 

delivered an airplane since 2007 and is 

working on acquiring the means to start 

up their production line again. The FAA 

is not aware that either of these 

manufacturers is considering a new 

airplane for part 23 type certification in 

the future and therefore this proposed 

rulemaking would most likely not add 

costs to these two manufacturers 

because the proposed rule only affects 

new part 23 type certificates. 

For the remaining two reciprocating 

engine part 23 airplane manufacturers, 

their last type certificates were issued in 

1961 and 1970. The 1961 type certificate 

was issued for the only airplane this 

manufacturer produces and the 

manufacturer with the 1970 type 

certificate produces one other airplane 

that was type certificated in 1941. The 

last small entity manufacturer produces 

only turboprop airplanes and it started 

delivering airplanes in 2007. Again, the 

FAA is not aware that any of these 

manufacturers is considering a new 

airplane for part 23 type certification in 

the future and therefore this proposed 

rulemaking would most likely not add 

costs for it. 

While this rulemaking may enable the 

creation of new manufacturers, the FAA 

is not aware of any new small entity 

part 23 manufacturers who want a type 

certification in the future for a new part 

23 airplane. However, by simplifying 

and lowering the costs for certification 

of new small airplanes, barriers to entry 

may be lowered and thus new 

manufacturers may emerge. 

6. Cost and Affordability for Small 

Entities 

In 2009, a joint FAA/industry team 

finalized the Part 23 CPS. This proposed 

rulemaking resulted from this study by 

the recommendation to use consensus 

standards to supplement the regulatory 

language. Since then, the FAA and the 

part 23 industry have worked together 

to develop common part 23 airplane 

certification requirements for this 

rulemaking. In 2011, with the Part 23 

CPS as a foundation, the FAA formed 

the Part 23 Reorganization ARC. The 

ARC consisted of large and small entity 

domestic and international businesses. 

We contacted the part 23 airplane 

manufacturers, the ARC, and GAMA for 

specific cost estimates for each section 

change for the rule and they all believe 

that this proposed rule would have a 

minimal cost impact on their operations 

and in many cases, would have 

significant cost savings by streamlining 

the part 23 type certification process. 

Many of the ARC members collaborated 

and provided a joint cost estimate for 

the proposed rule. 

The ARC has informed us that the 

proposed rule would save the 

manufacturers design time for the 

certification of part 23 airplanes by 

reducing the number of exemptions, 

equivalent level of safety findings and 

special conditions required to 

incorporate new and future technology 

into their new airplane certifications. 

The proposed rule would also require 

manuals to be updated and database 

development. We expect these updates 

to be minimal and request commen on 

these anticipated costs and overall 

reduction in paperwork burden. 

The ARC has also informed us that 

every other section of this proposed rule 

would be cost-neutral since the majority 

of the prescriptive requirements in part 

23 would be moved from part 23. The 

FAA expects that these current 

requirements would form the basis for 

consensus standards that would be used 

as a means of compliance to the 

proposed performance based 

regulations. 

The FAA expects this proposed rule 

could have a positive economic impact 

to small entities because it would enable 

new businesses to produce new part 23 

type certificated airplanes while 

maintaining a safe operating 

environment in the NAS. This proposal 

is based on the ARC’s recommendations 

and would allow for the use of 

consensus standards that have been 

developed in partnership with industry. 

Therefore, the FAA believes that this 

proposed rule could have a positive 

significant economic impact on a 

substantial number of entities. 

7. Alternative Analysis 

a. Alternative 1 

The FAA would continue to issue 

special conditions, exemptions, and 

equivalent level of safety findings to 

certificate part 23 airplanes. As this 

approach would not follow 

congressional direction, we choose not 

to continue with the status quo. 

b. Alternative 2 

The FAA would continue to enforce 

the current regulations that affect stall 

and controllability. The FAA rejected 

this alternative because the accident rate 

for part 23 airplanes identified a safety 

issue that had to be addressed. 

c. Alternative 3 

The FAA notes that a multi-engine 

part 23 aircraft manufacturer could 

decide it wants to comply with 

§ 23.200(b) by making the airplane 

capable of climbing after a critical loss 

by installing larger engines. But this is 

a very expensive alternative that would 

raise certification costs and operating 

costs and we believe that part 23 aircraft 

manufacturers would not make the 

airplane capable of climbing after a 

critical loss by installing larger engines. 

The FAA solicits comments regarding 

this determination. 

C. International Trade Impact 

Assessment 

The Trade Agreements Act of 1979 

(Pub. L. 96–39), as amended by the 

Uruguay Round Agreements Act (Pub. 

L. 103–465), prohibits Federal agencies 

from establishing standards or engaging 

in related activities that create 

unnecessary obstacles to the foreign 

commerce of the United States. 

Pursuant to these Acts, the 

establishment of standards is not 

considered an unnecessary obstacle to 

the foreign commerce of the United 

States, so long as the standard has a 

legitimate domestic objective, such as 

the protection of safety, and does not 

operate in a manner that excludes 

imports that meet this objective. The 

statute also requires consideration of 

international standards and, where 

appropriate, that they be the basis for 

U.S. standards. The FAA has assessed 

the potential effect of this proposed rule 

and determined that the standards are 

necessary for aviation safety and would 

not create unnecessary obstacles to the 

foreign commerce of the United States. 

D. Unfunded Mandates Assessment 

Title II of the Unfunded Mandates 

Reform Act of 1995 (Pub. L. 104–4) 

requires each Federal agency to prepare 

a written statement assessing the effects 

of any Federal mandate in a proposed or 

final agency rule that may result in an 

expenditure of $100 million or more (in 

1995 dollars) in any one year by State, 

local, and tribal governments, in the 

aggregate, or by the private sector; such 

a mandate is deemed to be a ‘‘significant 

regulatory action.’’ The FAA currently 

uses an inflation-adjusted value of 

$155.0 million in lieu of $100 million. 

This proposed rule does not contain 

such a mandate; therefore, the 

requirements of Title II of the Act do not 

apply. 

E. Paperwork Reduction Act 

The Paperwork Reduction Act of 1995 

(44 U.S.C. 3507(d)) requires that the 

FAA consider the impact of paperwork 

and other information collection 

burdens imposed on the public. The 

information requirements for aircraft 

certification are covered by existing 

OMB No. 2120–0018. Burdens 

associated with special conditions, 

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29https://my.faa.gov/org/linebusiness/avs/offices/

air/tools/cert.html. 30A report from the 14 CFR part 23 

Reorganization Aviation Rulemaking Committee to 

the Federal Aviation Administration; 

Recommendation for increasing the safety of small 

general aviation airplanes certificated to 14 CFR 

part 23, June 5, 2013, Table 7.1—Special 

Conditions, Exemptions, Equivalent Safety 

Findings, Page 55. 

31 Ibid., 54. 

32 2014 FAA Bay Band, Average K Band Salary 

(Rest of the U.S.) plus wage multiplier for benefits 

https://employees.faa.gov/org/staffoffices/ahr/

program_policies/policy_guidance/hr_policies/

hrpm/comp/comp_ref/2014payadjustment/. 

33 2014 FAA Bay Band, Average I Band Salary 

(Rest of the U.S.) plus wage multiplier for benefits 

https://employees.faa.gov/org/staffoffices/ahr/

program_policies/policy_guidance/hr_policies/

hrpm/comp/comp_ref/2014payadjustment/. 

34National Occupational Employment and Wage 

Estimates United States, May 2014; Aerospace 

Engineer mean hourly wage, NAIC code 17–2011 

plus wage multiplier for benefits http://

www.bls.gov/oes/current/oes_nat.htm#17-0000. A 

more detailed discussion is provided in the ‘‘Costs’’ 

section below. 

ELOS, and exemptions are not 

quantified in this collection because the 

need to seek relief under one of these 

options is dependent on each applicant 

and is difficult to quantify. It is 

expected that this rulemaking would 

reduce the number of special 

conditions, ELOS, and exemptions filed, 

thus reducing paperwork and 

processing time for both the FAA and 

industry. It would also maintain the 

fundamental safety requirements from 

the current part 23 regulations but allow 

more flexibility in airplane designs, 

faster adoption of safety enhancing 

technology, and reduce the regulatory 

cost burden. To estimate savings driven 

by this change, the FAA counted the 

special conditions, ELOS, and 

exemption applications submitted to the 

FAA for part 23 aircraft between 2012 

and 2013 and divided the number by 

two years for an average of 47 

applications per year.29 The ARC report 

offered a similar average of 37 

applications per year.30 Additionally, 

the FAA counted the number of pages 

per application for all 47 applications to 

obtain an average number of pages per 

application. For special conditions, 

there were approximately 21 pages, 16 

pages for an exemption, and 15 pages 

per ELOS application. The FAA 

assumes that the applicant and each 

FAA office that reviews the application 

spend 8 hours on research, 

coordination, and review per page. The 

ARC also noted ‘‘an ELOS finding or 

exemption can take the FAA between 4 

to 12 months to develop and approve. 

The applicant spends roughly the same 

amount of time as the FAA in proposing 

what they need and responding to FAA 

questions for SC, exemption, or 

ELOS.’’ 31

The number of applications is 

multiplied by the number of pages and 

by the hourly wage for the applicant and 

different FAA offices to account for the 

cost to the FAA and the applicant. The 

estimated hourly wage is $74.10 for a 

Small Airplane Directorate employee,32

$50.75 for an Aircraft Certificate Office 

employee,33 and $60.58 for an 

engineer 34 employed by the applicant. 

Annual cost equals the sum of the 

associated costs of special conditions, 

exemptions, plus equivalent level of 

safety. Yearly cost totals roughly 

$502,469 for the Small Airplane 

Directorate, $344,172 for Aircraft 

Certificate Offices, and $410,823 for the 

applicants. Tables 1, 2, and 3 show cost 

by office and applicant as well as by 

special condition, exemption, and 

ELOS. 

TABLE 1—SAVINGS FROM SPECIAL CONDITIONS (SC) * 

Part 23 Section 

Average 

number of SC 

(2012–2013) 

Average 

number of 

pages 

FAA SAD FAA ACO Applicant 

Man-hours Savings Man-hours Savings Man-hours Savings 

143 ............................... 0.5 20.8 83 $6,165 83 $4,223 83 $5,040 

171 ............................... 0.5 20.8 83 6,165 83 4,223 83 5,040 

173 ............................... 0.5 20.8 83 6,165 83 4,223 83 5,040 

175 ............................... 0.5 20.8 83 6,165 83 4,223 83 5,040 

177 ............................... 0.5 20.8 83 6,165 83 4,223 83 5,040 

251 ............................... 0.5 20.8 83 6,165 83 4,223 83 5,040 

361 ............................... 1 20.8 166 12,330 166 8,445 166 10,081 

562 ............................... 1 20.8 166 12,330 166 8,445 166 10,081 

572 ............................... 0.5 20.8 83 6,165 83 4,223 83 5,040 

573 ............................... 0.5 20.8 83 6,165 83 4,223 83 5,040 

574 ............................... 0.5 20.8 83 6,165 83 4,223 83 5,040 

613 ............................... 0.5 20.8 83 6,165 83 4,223 83 5,040 

627 ............................... 0.5 20.8 83 6,165 83 4,223 83 5,040 

629 ............................... 1.5 20.8 250 18,495 250 12,668 250 15,121 

901 ............................... 1 20.8 166 12,330 166 8,445 166 10,081 

939 ............................... 0.5 20.8 83 6,165 83 4,223 83 5,040 

951 ............................... 1 20.8 166 12,330 166 8,445 166 10,081 

961 ............................... 1 20.8 166 12,330 166 8,445 166 10,081 

973 ............................... 1 20.8 166 12,330 166 8,445 166 10,081 

977 ............................... 1.5 20.8 250 18,495 250 12,668 250 15,121 

1141 ............................. 0.5 20.8 83 6,165 83 4,223 83 5,040 

1301 ............................. 0.5 20.8 83 6,165 83 4,223 83 5,040 

1305 ............................. 1 20.8 166 12,330 166 8,445 166 10,081 

1308 ............................. 0.5 20.8 83 6,165 83 4,223 83 5,040 

1309 ............................. 1 20.8 166 12,330 166 8,445 166 10,081 

1329 ............................. 0.5 20.8 83 6,165 83 4,223 83 5,040 

1337 ............................. 0.5 20.8 83 6,165 83 4,223 83 5,040 

1521 ............................. 1 20.8 166 12,330 166 8,445 166 10,081 

1557 ............................. 1 20.8 166 12,330 166 8,445 166 10,081 

3Pt Restraint with Airbag ............................ 0.5 20.8 83 6,165 83 4,223 83 5,040 

Inflatable Restraint ....... 0.5 20.8 83 6,165 83 4,223 83 5,040 

Electronic Engine Controls ........................... 0.5 20.8 83 6,165 83 4,223 83 5,040 

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TABLE 1—SAVINGS FROM SPECIAL CONDITIONS (SC) *—Continued 

Part 23 Section 

Average 

number of SC 

(2012–2013) 

Average 

number of 

pages 

FAA SAD FAA ACO Applicant 

Man-hours Savings Man-hours Savings Man-hours Savings 

Fuel Jettisoning ............ 0.5 20.8 83 6,165 83 4,223 83 5,040 

Load Alleviation System 0.5 20.8 83 6,165 83 4,223 83 5,040 

Side Facing Seat with 

Airbag ....................... 0.5 20.8 83 6,165 83 4,223 83 5,040 

Totals .................... 24.5 728 4077 302,080 4077 206,914 4077 246,983 

* These numbers are subject to rounding error. 

TABLE 2—SAVINGS FROM EXEMPTIONS * 

Part 23 Section 

Average 

number 

exemptions 

(2012–2013) 

Average 

number of 

pages 

FAA SAD FAA ACO Applicant 

Man-hours Savings Man-hours Savings Man-hours Savings 

1359 ............................. 0.5 15.6 62.4 $4,624 62 $3,167 62 $3,780 

1549 ............................. 0.5 15.6 62.4 4,624 62 3,167 62 3,780 

177 ............................... 0.5 15.6 62.4 4,624 62 3,167 62 3,780 

49 ................................. 1 15.6 124.8 9,247 125 6,334 125 7,561 

562 ............................... 1 15.6 124.8 9,247 125 6,334 125 7,561 

1419 ............................. 0.5 15.6 62.4 4,624 62 3,167 62 3,780 

Totals .................... 4 94 499 36,989 499 25,336 499 30,243 

* These numbers are subject to rounding error. 

TABLE 3—SAVINGS FROM EQUIVALENT LEVEL OF SAFETY (ELOS) * 

Part 23 Section 

Average 

number ELOS 

(2012–2013) 

Average 

number of 

pages 

FAA SAD FAA ACO Applicant 

Man-hours Savings Man-hours Savings Savings Man-hours 

145 ............................... 1 14.9 119.2 $8,832 119 $6,050 119 $7,221 

207 ............................... 1 14.9 119.2 8,832 119 6,050 119 7,221 

672 ............................... 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

777 ............................... 1.5 14.9 178.8 13,249 179 9,075 179 10,832 

779 ............................... 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

781 ............................... 1.5 14.9 178.8 13,249 179 9,075 179 10,832 

807 ............................... 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

815 ............................... 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

841 ............................... 1 14.9 119.2 8,832 119 6,050 119 7,221 

973 ............................... 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

1092 ............................. 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

1145 ............................. 1 14.9 119.2 8,832 119 6,050 119 7,221 

1305 ............................. 1.5 14.9 178.8 13,249 179 9,075 179 10,832 

1311 ............................. 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

1353 ............................. 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

1357 ............................. 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

1397 ............................. 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

1401 ............................. 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

1419 ............................. 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

1443 ............................. 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

1505 ............................. 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

1545 ............................. 0.5 14.9 59.6 4,416 60 3,025 60 3,611 

1549 ............................. 2.5 14.9 298 22,081 298 15,125 298 18,054 

Totals .................... 19 343 2205 163,400 2205 111,923 2205 133,597 

* These numbers are subject to rounding error. 

Using these yearly cost estimates, over 

20 years $25.1 million in man-hours 

would be spent on applying for and 

processing special conditions, 

exemptions, and ELOS. However under 

the proposed rule, the FAA believes that 

the need to demonstrate compliance 

through special conditions, exemptions, 

or ELOS would largely be eliminated. 

Instead new products will simply need 

to demonstrate compliance by following 

consensus standards acceptable to the 

Administrator, or by submitting their 

own novel demonstrations of 

compliance. As a conservative estimate, 

the FAA estimates that special 

conditions, exemptions, and ELOS 

would be reduced by half for a savings 

to the FAA and applicant of roughly 

$12.6 million ($5.8 million present 

value). Savings by year is shown in the 

chart below. The FAA asks for comment 

regarding the amount of reduction in the 

alternative means of compliance. 

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In addition to this savings, there 

would also be additional paperwork 

burden associated with proposed 

§ 23.200. As proposed, this provision 

could result in a change to a limitation 

or a performance number in the flight 

manual, which would reqire an update 

to the training courseware or flight 

manual. Industry believes that this 

proposed change could cost from 

$100,000 to $150,000. Therefore, the 

FAA uses $125,000 (($100,000 + 

$150,000)/2) as an average cost for this 

proposed change. 

There would also be additional 

paperwork associated with this 

requirement that is not part of the costs 

discussed above. The FAA estimates the 

paperwork costs for these proposed 

provisions by multiplying the number of 

hours the FAA estimates for each page 

of paperwork, by the number of pages 

for the training courseware, or flight 

manual, by the hourly rate of the person 

responsible for the update. The Small 

Aircraft Directorate of the FAA provided 

average hourly times and the number of 

additional pages of paperwork the 

proposal would add. The FAA estimates 

that this section would add a total of 

four pages to the training courseware 

and flight manual. The FAA also 

estimates that it would take a part 23 

certification engineer eight hours to 

complete the one page required for each 

new type certification. The eight hours 

to complete a page includes the 

research, coordination, and review each 

document requires. Therefore, the FAA 

estimates the total paperwork costs for 

proposed controllability section would 

be about $1,939 (8 hours * 4 pages * 

$60.58 per hour) in 2014 dollars. 

The FAA is expecting part 23 airplane 

manufacturers to update their 

engineering procedures manuals to 

reflect the changes from this proposed 

rulemaking. However, most of the 

engineering procedures manuals are not 

written around the requirements of part 

23, but around the requirements of part 

21. Since the part 23 changes would 

have minimal impact on the part 21 

requirements, there should be little 

change in the engineering procedures 

manuals. Conversations with industry 

indicate that there may need to be some 

changes to the engineering manuals to 

describe how the accepted means of 

compliance must be related to the 

regulations. Depending on the 

complexity of each company’s manual, 

industry estimates that these changes 

could run from about $50,000 up to 

$200,000. This would be a one-time cost 

per new type certification. 

Since the FAA is unable to determine 

the complexity of each company’s 

manual, we assume that the 

manufacturers of the two new part 23 

reciprocating engine airplane type 

certifications, discussed in the ‘‘Fleet 

Discussion’’ section of the regulatory 

impact analysis, would spend $50,000 

to make the changes to the engineering 

manual. We also assume that the one 

new part 23 turboprop airplane 

certification and the two new part 23 

turbojet airplane certifications, 

discussed in the ‘‘Fleet Discussion’’ 

section, would use the more complex 

and costly approach of $200,000. 

The FAA notes that either the simple 

approach or the more complex approach 

to updating the manuals could also 

either take place in-house or could be 

contracted out to a consultant. 

Table 4 shows the total costs for the 

proposed changes to the controllability 

section. 

TABLE 4—ESTIMATE COSTS FOR UPDATING ENGINEERING MANUALS

[2014 $] 

Airplane 

Number of 

estimated 

new type 

certificates 

Simple 

approach 

Complex 

approach Total 

Recip ................................................................................................................................ 2 $50,000 $0 $100,000 

Turboprop ........................................................................................................................ 1 0 200,000 200,000 

Turbojet ............................................................................................................................ 2 0 200,000 400,000 

Total .......................................................................................................................... .................... .................... .................... 700,000 

* These numbers are subject to rounding error. 

F. International Compatibility and 

Cooperation 

In keeping with U.S. obligations 

under the Convention on International 

Civil Aviation, it is FAA policy to 

conform to International Civil Aviation 

Organization (ICAO) Standards and 

Recommended Practices to the 

maximum extent practicable. The FAA 

has reviewed the corresponding ICAO 

Standards and Recommended Practices 

and has identified the following 

differences with these proposed 

regulations. The ICAO Standards for 

small airplanes use weight and 

propulsion to differentiate between 

some requirements. The proposed 

regulations use certification levels and 

performance to differentiate between 

some requirements. Furthermore, part 

23 will still allow the certification of 

airplanes up to 19,000 pounds. If this 

proposal is adopted, the FAA intends to 

file these differences with ICAO. 

Executive Order (EO) 13609, Promoting 

International Regulatory Cooperation, 

(77 FR 26413, May 4, 2012) promotes 

international regulatory cooperation to 

meet shared challenges involving 

health, safety, labor, security, 

environmental, and other issues and 

reduce, eliminate, or prevent 

unnecessary differences in regulatory 

requirements. The FAA has analyzed 

this action under the policy and agency 

responsibilities of Executive Order 

13609, Promoting International 

Regulatory Cooperation. The agency has 

determined that this action would 

eliminate differences between U.S. 

aviation standards and those of other 

CAAs by aligning the revised part 23 

standards with the new CS–23 

standards that are being developed 

concurrently by EASA. Several other 

CAAs are participating in this effort and 

intend to either adopt the new part 23 

or CS–23 regulations or revise their 

airworthiness standards to align with 

these new regulations. 

The Part 23 Reorganization ARC 

included participants from several 

foreign CAAs and international 

members from almost every GA 

manufacturer of both airplanes and 

avionics. It also included several LightSport Aircraft manufacturers who are 

interested in certificating their products 

using the airworthiness standards 

contained in part 23. The rulemaking 

and means of compliance documents 

are international efforts. Authorities 

from Europe, Canada, Brazil, China, and 

New Zealand all are working to produce 

similar rules. These rules, while not 

identical, are intended to allow the use 

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of the same set of industry developed 

means of compliance. Industry has told 

that FAA that it is very costly to address 

the differences that some contrived 

means of compliance imposes. If there 

is substantial agreement between the 

major CAAs to use the same industry 

means of compliance document, then 

U.S. manufactures expect a significant 

saving for exporting their products. 

Furthermore, this project is a 

harmonization project between the FAA 

and EASA. 

EASA has worked a parallel 

rulemaking program for CS–23. The 

FAA provided comments to the EASA 

A–NPA The EASA and other authorities 

will have an opportunity to comment on 

this NPRM when it is published. These 

efforts will allow the FAA, EASA and 

other authorities to work toward a 

harmonized set of regulations when the 

final rules are published. 

G. Environmental Analysis 

FAA Order 1050.1F identifies FAA 

actions that are categorically excluded 

from preparation of an environmental 

assessment or environmental impact 

statement under the National 

Environmental Policy Act in the 

absence of extraordinary circumstances. 

The FAA has determined this 

rulemaking action qualifies for the 

categorical exclusion identified in 

paragraph 5–6.6 and involves no 

extraordinary circumstances. 

H. Regulations Affecting Intrastate 

Aviation in Alaska 

Section 1205 of the FAA 

Reauthorization Act of 1996 (110 Stat. 

3213) requires the Administrator, when 

modifying 14 CFR regulations in a 

manner affecting intrastate aviation in 

Alaska, to consider the extent to which 

Alaska is not served by transportation 

modes other than aviation, and to 

establish appropriate regulatory 

distinctions. Because this proposed rule 

would apply to GA airworthiness 

standards, it could, if adopted, affect 

intrastate aviation in Alaska. The FAA, 

therefore, specifically requests 

comments on whether there is 

justification for applying the proposed 

rule differently in intrastate operations 

in Alaska. 

VIII. Executive Order Determination 

A. Executive Order 13132, Federalism 

The FAA has analyzed this proposed 

rule under the principles and criteria of 

Executive Order 13132, Federalism. The 

agency has determined that this action 

would not have a substantial direct 

effect on the States, or the relationship 

between the Federal Government and 

the States, or on the distribution of 

power and responsibilities among the 

various levels of government, and, 

therefore, would not have Federalism 

implications. 

B. Executive Order 13211, Regulations 

That Significantly Affect Energy Supply, 

Distribution, or Use 

The FAA analyzed this proposed rule 

under Executive Order 13211, Actions 

Concerning Regulations that 

Significantly Affect Energy Supply, 

Distribution, or Use (May 18, 2001). The 

agency has determined that it would not 

be a ‘‘significant energy’’ action under 

the executive order and would not be 

likely to have a significant adverse effect 

on the supply, distribution, or use of 

energy. 

IX. Additional Information 

A. Comments Invited 

The FAA invites interested persons to 

participate in this rulemaking by 

submitting written comments, data, or 

views. The agency also invites 

comments relating to the economic, 

environmental, energy, or federalism 

impacts that might result from adopting 

the proposals in this document. The 

most helpful comments reference a 

specific portion of the proposal, explain 

the reason for any recommended 

change, and include supporting data. To 

ensure the docket does not contain 

duplicate comments, commenters 

should send only one copy of written 

comments, or if comments are filed 

electronically, commenters should 

submit only one time. 

The FAA will file in the docket all 

comments it receives, as well as a report 

summarizing each substantive public 

contact with FAA personnel concerning 

this proposed rulemaking. Before acting 

on this proposal, the FAA will consider 

all comments it receives on or before the 

closing date for comments. The FAA 

will consider comments filed after the 

comment period has closed if it is 

possible to do so without incurring 

expense or delay. The agency may 

change this proposal in light of the 

comments it receives. 

Proprietary or Confidential Business 

Information: Commenters should not 

file proprietary or confidential business 

information in the docket. Such 

information must be sent or delivered 

directly to the person identified in the 

FOR FURTHER INFORMATION CONTACT

section of this document, and marked as 

proprietary or confidential. If submitting 

information on a disk or CD–ROM, mark 

the outside of the disk or CD–ROM, and 

identify electronically within the disk or 

CD–ROM the specific information that 

is proprietary or confidential. 

Under 14 CFR 11.35(b), if the FAA is 

aware of proprietary information filed 

with a comment, the agency does not 

place it in the docket. It is held in a 

separate file to which the public does 

not have access, and the FAA places a 

note in the docket that it has received 

it. If the FAA receives a request to 

examine or copy this information, it 

treats it as any other request under the 

Freedom of Information Act (5 U.S.C. 

552). The FAA processes such a request 

under Department of Transportation 

procedures found in 49 CFR part 7. 

B. Availability of Rulemaking 

Documents 

An electronic copy of rulemaking 

documents may be obtained from the 

Internet by— 

1. Searching the Federal eRulemaking 

Portal (http://www.regulations.gov); 

2. Visiting the FAA’s Regulations and 

Policies Web page at http://

www.faa.gov/regulations_policies or 

3. Accessing the Government Printing 

Office’s Web page at http://

www.gpo.gov/fdsys/. 

Copies may also be obtained by 

sending a request to the Federal 

Aviation Administration, Office of 

Rulemaking, ARM–1, 800 Independence 

Avenue SW., Washington, DC 20591, or 

by calling (202) 267–9680. Commenters 

must identify the docket or notice 

number of this rulemaking. 

All documents the FAA considered in 

developing this proposed rule, 

including economic analyses and 

technical reports, may be accessed from 

the Internet through the Federal 

eRulemaking Portal referenced in item 

(1) above. 

Appendix 1 to the Preamble—Current 

to Proposed Regulations CrossReference Table 

The below cross-reference table is 

intended to permit easy access from 

proposed to current regulations. The 

preamble is organized topical, sectionby-section, proposed to current 

regulations. This table should assist the 

reader in following the section 

discussions contained in the preamble. 

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Current section Title Proposed section Proposed title 

Subpart A—General 

23.1 ..................... Applicability .................................................. 23.1 ............................................ Applicability. 

23.2 ..................... Special retroactive requirements ................. .................................................... —Deleted— 

23.3 ..................... Airplane categories ...................................... 23.5 ............................................ Certification of normal category airplanes. 

...................................................................... 23.10 .......................................... Accepted means of compliance. 

Subpart B—Flight 

23.21 ................... Proof of compliance .................................... 23.100 ........................................ Weight and center of gravity. 

23.23 ................... Load distribution limits ................................. 23.100 ........................................ Weight and center of gravity. 

23.25 ................... Weight limits ................................................ 23.100 ........................................ Weight and center of gravity. 

23.29 ................... Empty weight and corresponding center of 

gravity.

23.100 ........................................ Weight and center of gravity. 

23.31 ................... Removable ballast ....................................... 23.100 ........................................ Weight and center of gravity. 

23.33 ................... Propeller speed and pitch limits .................. 23.900 ........................................ Powerplant installation. 

23.45 ................... Performance—General ................................ 23.105 ........................................ Performance. 

23.49 ................... Stalling speed .............................................. 23.110 ........................................ Stall Speed. 

23.51 ................... Takeoff speeds ............................................ 23.115 ........................................ Takeoff performance. 

23.53 ................... Takeoff performance ................................... 23.115 ........................................ Takeoff performance. 

23.55 ................... Accelerate-stop distance ............................. 23.115 ........................................ Takeoff performance. 

23.57 ................... Takeoff path ................................................ 23.115 ........................................ Takeoff performance. 

23.59 ................... Takeoff distance and takeoff run ................ 23.115 ........................................ Takeoff performance. 

23.61 ................... Takeoff flight path ........................................ 23.115 ........................................ Takeoff performance. 

23.63 ................... Climb: General ............................................ 23.120 ........................................ Climb. 

23.65 ................... Climb: All engines operating ....................... 23.120 ........................................ Climb.

23.66 ................... Takeoff climb: one engine inoperative ........ 23.125 ........................................ Climb. 

23.67 ................... Climb: One engine inoperative .................... 23.120 ........................................ Climb. 

23.69 ................... Enroute climb/descent ................................. 23.125 ........................................ Climb. 

23.71 ................... Glide: single engine airplanes ..................... 23.125 ........................................ Climb.

23.73 ................... Reference landing approach speed ............ 23.130 ........................................ Landing. 

23.75 ................... Landing distance ......................................... 23.130 ........................................ Landing. 

23.77 ................... Balked landing ............................................. 23.120 ........................................ Climb. 

23.141 ................. Flight Characteristics—General .................. 23.200 ........................................ Controllability. 

23.143 ................. Controllability and Maneuverability—General.23.200 ........................................ Controllability. 

23.145 ................. Longitudinal control ..................................... 23.200 ........................................ Controllability. 

23.147 ................. Directional and lateral control ..................... 23.200 ........................................ Controllability. 

23.149 ................. Minimum control speed ............................... 23.200 ........................................ Controllability. 

23.151 ................. Acrobatic maneuvers ................................... 23.200 ........................................ Controllability. 

23.153 ................. Control during landings ............................... 23.200 ........................................ Controllability. 

23.155 ................. Elevator control force in maneuvers ........... 23.200 ........................................ Controllability. 

23.157 ................. Rate of roll ................................................... 23.200 ........................................ Controllability. 

23.161 ................. Trim ............................................................. 23.205 ........................................ Trim. 

23.171 ................. Stability—General ........................................ 23.210 ........................................ Stability. 

23.173 ................. Static longitudinal stability ........................... 23.210 ........................................ Stability. 

23.175 ................. Demonstration of static longitudinal stability 23.210 ........................................ Stability. 

23.177 ................. Static directional and lateral stability ........... 23.210 ........................................ Stability. 

23.179 ................. Instrument stick force measurements ......... 23.210 ........................................ Stability. 

23.181 ................. Dynamic stability ......................................... 23.210 ........................................ Stability. 

23.201 ................. Wings level stall .......................................... 23.215 ........................................ Stall characteristics, stall warning, and 

spins. 

23.203 ................. Turning Flight and accelerated turning 

stalls.

23.215 ........................................ Stall characteristics, stall warning, and 

spins. 

23.207 ................. Stall Warning ............................................... 23.215 ........................................ Stall characteristics, stall warning, and 

spins. 

23.221 ................. Spinning ....................................................... 23.215 ........................................ Stall characteristics, stall warning, and 

spins. 

23.231 ................. Longitudinal stability and control ................. 23.220 ........................................ Ground handling. 

23.233 ................. Directional stability and control ................... 23.220 ........................................ Ground handling. 

23.235 ................. Operation on unpaved surfaces .................. 23.220 ........................................ Ground handling. 

23.237 ................. Operation on water ...................................... 23.220 ........................................ Ground handling. 

23.239 ................. Spray characteristics ................................... 23.220 ........................................ Ground handling. 

23.251 ................. Vibration and buffeting ................................ 23.225 ........................................ Vibration, buffeting, and high-speed characteristics. 

23.253 ................. High speed characteristics .......................... 23.225 ........................................ Vibration, buffeting, and high-speed characteristics. 

23.255 ................. Out of trim characteristics ........................... 23.225 ........................................ Vibration, buffeting, and high-speed characteristics. 

23.230 ........................................ Performance and flight characteristics requirements for flight in icing conditions. 

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Subpart C—Structure 

23.301 ................. Loads ........................................................... 23.310, 23.330 ........................... Structural design loads, Limit and ultimate 

loads. 

(a) ........................ ...................................................................... 23.330 ........................................ Limit and ultimate loads. 

(b) ........................ ...................................................................... 23.310 ........................................ Structural design loads. 

(c) ........................ ...................................................................... 23.310 ........................................ Structural design loads. 

(d) ........................ ...................................................................... 23.310 ........................................ Structural design loads. 

23.302 ................. Canard or tandem wing configurations ....... 23.310 ........................................ Structural design loads. 

23.303 ................. Factors of safety .......................................... 23.330 ........................................ Limit and ultimate loads. 

23.305 ................. Strength and deformation ............................ 23.400 ........................................ Structural strength. 

23.305 ........................................ Interaction of systems and structures. 

23.307 ................. Proof of structure ......................................... 23.400 ........................................ Structure strength. 

23.321 ................. Flight Loads—General ................................ 23.310 ........................................ Structural design loads. 

(a) ........................ ...................................................................... 23.310 ........................................ Structural design loads. 

(b) ........................ ...................................................................... 23.300 ........................................ Structural design envelope. 

(c) ........................ ...................................................................... 23.300 ........................................ Structural design envelope. 

23.331 ................. Symmetrical flight conditions ....................... 23.310 ........................................ Structural design loads. 

23.333 ................. Flight envelope ............................................ 23.300 ........................................ Structural design envelope. 

(a) ........................ ...................................................................... 23.300 ........................................ Structural design envelope. 

(b) ........................ ...................................................................... 23.300 ........................................ Structural design envelope. 

(c) ........................ ...................................................................... 23.315 ........................................ Flight load conditions. 

(d) ........................ ...................................................................... 23.300 ........................................ Structural design envelope. 

23.335 ................. Design airspeeds ......................................... 23.300 ........................................ Structural design envelope. 

23.337 ................. Limit maneuvering load factors ................... 23.300 ........................................ Flight load conditions. 

(a) ........................ ...................................................................... 23.300 ........................................ Structural design envelope. 

(b) ........................ ...................................................................... 23.300 ........................................ Structural design envelope. 

(c) ........................ ...................................................................... Means of Compliance.

23.341 ................. Gust load factors ......................................... 23.315 ........................................ Flight load conditions. 

23.343 ................. Design fuel loads ......................................... 23.300 ........................................ Structural design envelope. 

(a) ........................ ...................................................................... 23.300 ........................................ Structural design envelope. 

(b) ........................ ...................................................................... 23.300 ........................................ Structural design envelope. 

(c) ........................ ...................................................................... Means of Compliance.

23.345 ................. High lift devices ........................................... 23.325 ........................................ Component loading conditions. 

23.347 ................. Unsymmetrical flight loads .......................... 23.315 ........................................ Flight load conditions. 

23.349 ................. Rolling conditions ........................................ 23.315 ........................................ Flight load conditions. 

23.351 ................. Yawing conditions ....................................... 23.315 ........................................ Flight load conditions. 

23.361 ................. Engine torque .............................................. 23.325 ........................................ Component loading conditions. 

23.363 ................. Side load on engine mount ......................... 23.325 ........................................ Component loading conditions. 

23.365 ................. Pressurized cabin loads .............................. 23.325 ........................................ Flight load conditions. 

(e) ........................ ...................................................................... 23.405 ........................................ Structural durability. 

23.367 ................. Unsymmetrical loads due to engine failure 23.315 ........................................ Flight load conditions. 

23.369 ................. Rear lift truss ............................................... Means of Compliance.

23.371 ................. Gyroscopic and aerodynamic loads ............ 23.325 ........................................ Component loading conditions. 

23.373 ................. Speed control devices ................................. 23.325 ........................................ Component loading conditions. 

23.391 ................. Control surface loads .................................. 23.325 ........................................ Component loading conditions. 

23.393 ................. Loads parallel to hinge line ......................... 23.325 ........................................ Component loading conditions. 

23.395 ................. Control system loads ................................... 23.325 ........................................ Component loading conditions. 

23.397 ................. Limit control forces and torques .................. 23.325 ........................................ Component loading conditions. 

23.399 ................. Dual control system ..................................... 23.325 ........................................ Component loading conditions. 

23.405 ................. Secondary control system ........................... 23.325 ........................................ Component loading conditions. 

23.407 ................. Trim tab effects ........................................... 23.325 ........................................ Component loading conditions. 

23.409 ................. Tabs ............................................................. 23.325 ........................................ Component loading conditions. 

23.415 ................. Ground gust conditions ............................... 23.325 ........................................ Component loading conditions. 

23.421 ................. Balancing loads ........................................... Means of Compliance.

23.423 ................. Maneuvering loads ...................................... 23.315 ........................................ Flight load conditions. 

23.425 ................. Gust loads ................................................... 23.315 ........................................ Flight load conditions. 

23.427 ................. Unsymmetrical loads due to engine failure 23.315 ........................................ Flight load conditions. 

23.441 ................. Maneuvering loads ...................................... 23.315 ........................................ Flight load conditions. 

23.443 ................. Gust loads ................................................... 23.315 ........................................ Flight load conditions. 

23.445 ................. Outboard fins or winglets ............................ Means of Compliance.

23.455 ................. Ailerons ........................................................ 23.325 ........................................ Component loading conditions. 

23.459 ................. Special devices ........................................... 23.325 ........................................ Component loading conditions. 

23.471 ................. Ground Loads—General ............................. 23.320 ........................................ Ground and water load conditions. 

23.473 ................. Ground load conditions and assumptions ... 23.320 ........................................ Ground and water load conditions. 

23.477 ................. Landing gear arrangement .......................... 23.320 ........................................ Ground and water load conditions. 

23.479 ................. Level landing conditions .............................. 23.320 ........................................ Ground and water load conditions. 

23.481 ................. Tail down landing conditions ....................... 23.320 ........................................ Ground and water load conditions. 

23.483 ................. One-wheel landing conditions ..................... 23.320 ........................................ Ground and water load conditions. 

23.485 ................. Side load conditions .................................... 23.320 ........................................ Ground and water load conditions. 

23.493 ................. Braked roll conditions .................................. 23.320 ........................................ Ground and water load conditions. 

23.497 ................. Supplementary conditions for tail wheels ... 23.320 ........................................ Ground and water load conditions. 

23.499 ................. Supplementary conditions for nose wheels 23.320 ........................................ Ground and water load conditions. 

23.505 ................. Supplementary conditions for skiplanes ..... 23.320 ........................................ Ground and water load conditions. 

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23.507 ................. Jacking loads ............................................... 23.320 ........................................ Ground and water load conditions. 

23.509 ................. Towing loads ............................................... 23.320 ........................................ Ground and water load conditions. 

23.511 ................. Ground load: unsymmetrical loads on multiple-wheel units.23.320 ........................................ Ground and water load conditions. 

23.521 ................. Water load conditions .................................. 23.320 ........................................ Ground and water load conditions. 

23.523 ................. Design weights and center of gravity positions.23.320 ........................................ Ground and water load conditions. 

23.525 ................. Application of loads ..................................... 23.320 ........................................ Ground and water load conditions. 

23.527 ................. Hull and main float load factors .................. 23.320 ........................................ Ground and water load conditions. 

23.529 ................. Hull and main float landing conditions ........ 23.320 ........................................ Ground and water load conditions. 

23.531 ................. Hull and main float takeoff conditions ......... 23.320 ........................................ Ground and water load conditions. 

23.533 ................. Hull and main float bottom pressures ......... 23.320 ........................................ Ground and water load conditions. 

23.535 ................. Auxiliary float loads ..................................... 23.320 ........................................ Ground and water load conditions. 

23.537 ................. Seawing loads ............................................. 23.320 ........................................ Ground and water load conditions. 

23.561 ................. Emergency Landing Conditions—General .. 23.600 ........................................ Emergency conditions. 

23.562 ................. Emergency landing dynamic conditions ...... 23.600 ........................................ Emergency conditions. 

23.571 ................. Metallic pressurized cabin structures .......... 23.405 ........................................ Structural durability. 

23.572 ................. Metallic wing, empennage, and associated 

structures.

23.405 ........................................ Structural durability. 

23.573 ................. Damage tolerance and fatigue evaluation 

of structure.

23.405 ........................................ Structural durability. 

23.574 ................. Metallic damage tolerance and fatigue 

evaluation of commuter category airplanes.

23.405 ........................................ Structural durability. 

23.575 ................. Inspections and other procedures ............... 23.405 ........................................ Structural durability. 

Subpart D—Design and Construction 

23.601 ................. General ........................................................ 23.500 ........................................ Structural design. 

23.603 ................. Materials and workmanship ........................ 23.500 ........................................ Structural design. 

23.605 ................. Fabrication methods .................................... 23.510 ........................................ Materials and processes. 

23.607 ................. Fasteners ..................................................... 23.505 ........................................ Protection of structure. 

23.609 ................. Protection of Structure ................................ 23.505 ........................................ Protection of structure. 

23.611 ................. Accessibility ................................................. 23.505 ........................................ Protection of structure. 

23.613 ................. Material strength properties and design values.23.510 ........................................ Materials and processes. 

23.619 ................. Special factors ............................................. 23.515 ........................................ Special factors of safety. 

23.621 ................. Casting factors ............................................ 23.515 ........................................ Special factors of safety. 

23.623 ................. Bearing factors ............................................ 23.515 ........................................ Special factors of safety. 

23.625 ................. Fitting factors ............................................... 23.515 ........................................ Special factors of safety. 

23.627 ................. Fatigue strength .......................................... 23.405 ........................................ Structural durability. 

23.629 ................. Flutter .......................................................... 23.410 ........................................ Aeroelasticity. 

23.641 ................. Proof of strength .......................................... Means of Compliance.

23.651 ................. Proof of strength .......................................... Means of Compliance.

23.655 ................. Installation ................................................... Means of Compliance.

23.657 ................. Hinges ......................................................... 23.515 ........................................ Special factors of safety. 

23.659 ................. Mass balance .............................................. 23.315 ........................................ Flight load conditions. 

23.671 ................. Control Surfaces—General.

(a) ........................ ...................................................................... 23.500 ........................................ Structural design. 

(b) ........................ ...................................................................... 23.1305 ...................................... Function and installation. 

23.672 ................. Stability augmentation and automatic and 

power-operated systems.

23.1305 ...................................... Function and installation. 

23.673 ................. Primary flight controls .................................. 23.1305 ...................................... Function and installation. 

23.675 ................. Stops ........................................................... 23.1305 ...................................... Function and installation. 

23.677 ................. Trim systems.

(a) ........................ ...................................................................... 23.700 ........................................ Flight control systems. 

(b) ........................ ...................................................................... 23.700 ........................................ Flight control systems. 

(c) ........................ ...................................................................... 23.410 ........................................ Aeroelasticity. 

(d) ........................ ...................................................................... 23.700 ........................................ Flight control systems. 

23.679 ................. Control system locks ................................... 23.1305 ...................................... Function and installation. 

23.681(a) ............. Limit load static tests ................................... 23.325(b) .................................... Component loading conditions. 

23.681(b) ............. Limit load static tests ................................... 23.515 ........................................ Special factors of safety. 

23.683 ................. Operation tests ............................................ 23.500(d) .................................... Structural design. 

23.685(a), (b), (c) Control system details ................................. 23.500(d) .................................... Structural design. 

23.685(d) ............. Control system details ................................. 23.1305 ...................................... Function and installation. 

23.687 ................. Spring devices ............................................. 23.410 and 23.500 ..................... Aeroelasticity and Structural design. 

23.689 ................. Cable systems.

(a) ........................ ...................................................................... 23.700 ........................................ Flight control systems. 

(b) ........................ ...................................................................... 23.325(b), 23.500(d) .................. Component loading conditions, Structural 

design. 

(c) ........................ ...................................................................... 23.325(b), 23.500(d) .................. Component loading conditions, Structural 

design. 

(d) ........................ ...................................................................... 23.325(b), 23.500(d) .................. Component loading conditions, Structural 

design. 

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Current section Title Proposed section Proposed title 

(e) ........................ ...................................................................... 23.325(b), 23.500(d) .................. Component loading conditions, Structural 

design. 

(f) ......................... ...................................................................... 23.700 ........................................ Flight control systems. 

23.691 ................. Artificial stall barrier system.

(a) ........................ ...................................................................... 23.700 ........................................ Flight control systems. 

(b) ........................ ...................................................................... 23.700 ........................................ Flight control systems. 

(c) ........................ ...................................................................... 23.1305 ...................................... Function and installation. 

(d) ........................ ...................................................................... 23.700 ........................................ Flight control systems. 

(e) ........................ ...................................................................... 23.700 ........................................ Flight control systems. 

(f) ......................... ...................................................................... 23.700 ........................................ Flight control systems. 

(g) ........................ ...................................................................... 23.1315 ...................................... Equipment, systems and Installations. 

23.693 ................. Joints ........................................................... 23.515 ........................................ Special factors of safety. 

23.697 ................. Wing flap controls.

(a) ........................ ...................................................................... 23.700 ........................................ Flight control systems. 

(b) and (c) ........... ...................................................................... 23.200 ........................................ Controllability. 

23.699 ................. Wing flap position indicator ......................... 23.1500 ...................................... Flightcrew interface. 

23.701 ................. Flap interconnection .................................... Means of Compliance.

23.703 ................. Takeoff warning system.

(a) ........................ ...................................................................... 23.700 ........................................ Flight control systems. 

(b) ........................ ...................................................................... 23.700 ........................................ Flight control systems. 

(c) ........................ ...................................................................... Definition.

23.721 ................. General ........................................................ 23.910 ........................................ Powerplant installation hazard assessment. 

23.723 ................. Shock absorption tests ................................ Means of Compliance.

23.725 ................. Limit drop tests ............................................ Means of Compliance.

23.726 ................. Ground load dynamic tests ......................... Means of Compliance.

23.727 ................. Reserve energy absorption drop tests ........ Means of Compliance.

23.729 ................. Landing gear extension and retraction system.

(a) ........................ ...................................................................... 23.705 ........................................ Landing gear systems. 

(b) ........................ ...................................................................... 23.705 ........................................ Landing gear systems. 

(c) ........................ ...................................................................... 23.705 ........................................ Landing gear systems. 

(d) ........................ ...................................................................... Means of Compliance.

(e) ........................ ...................................................................... 23.705 ........................................ Landing gear systems. 

(f) ......................... ...................................................................... 23.1315 ...................................... Equipment, systems and installation. 

(g) ........................ ...................................................................... Means of Compliance.

23.731 ................. Wheels ......................................................... 23.705 ........................................ Landing gear systems. 

23.733 ................. Tires.

(a) ........................ ...................................................................... 23.705 ........................................ Landing gear systems. 

(b) ........................ ...................................................................... Means of Compliance.

(c) ........................ ...................................................................... Means of Compliance.

23.735 ................. Brakes ......................................................... 23.705.

(a) ........................ ...................................................................... 23.705 ........................................ Landing gear systems. 

(1) ........................ ...................................................................... Means of Compliance.

(2) ........................ ...................................................................... Means of Compliance.

(b) ........................ ...................................................................... 23.705 ........................................ Landing gear systems. 

(c) ........................ ...................................................................... Means of Compliance.

(d) ........................ ...................................................................... 1315 ........................................... Equipment, systems and installation. 

(e) ........................ ...................................................................... 705 ............................................. Landing gear systems. 

(1) ........................ ...................................................................... Means of Compliance.

(2) ........................ ...................................................................... Means of Compliance.

23.737 ................. Skis .............................................................. 23.705 ........................................ Landing gear systems. 

23.745 ................. Nose/Tail wheel steering ............................. 23.1500 ...................................... Flightcrew interface. 

23.751 ................. Main float buoyancy.

(a) ........................ ...................................................................... 710 ............................................. Buoyancy for seaplanes and amphibians. 

(b) ........................ ...................................................................... Means of Compliance.

23.753 ................. Main float design ......................................... 23.320 ........................................ Ground and water load conditions. 

23.755 ................. Hulls ............................................................. 23.710 ........................................ Buoyancy for seaplanes and amphibians. 

23.757 ................. Auxiliary floats ............................................. 23.710 ........................................ Buoyancy for seaplanes and amphibians. 

23.771 ................. Pilot compartment.

(a) ........................ ...................................................................... 23.1500 ...................................... Flightcrew interface. 

(b) ........................ ...................................................................... 755 ............................................. Occupant physical environment. 

(c) ........................ ...................................................................... 755 ............................................. Occupant physical environment. 

23.773 ................. Pilot compartment view.

(a) ........................ ...................................................................... 1500 ........................................... Flightcrew interface. 

(b) ........................ ...................................................................... 23.755 ........................................ Occupant physical environment. 

23.775 ................. Windshields and windows.

(a), (b), (c), (d) .... ...................................................................... 23.755 ........................................ Occupant physical environment. 

(e) ........................ ...................................................................... Means of Compliance.

(f) ......................... ...................................................................... 23.1405 ...................................... Flight in icing conditions. 

(g) ........................ ...................................................................... Means of Compliance.

(h) ........................ ...................................................................... 23.755 ........................................ Occupant physical environment. 

23.777 ................. Cockpit controls ........................................... 23.1500 ...................................... Flightcrew interface. 

23.779 ................. Motion and effect of cockpit controls .......... 23.1500 ...................................... Flightcrew interface. 

23.781 ................. Cockpit control knob shape ......................... 23.1500 ...................................... Flightcrew interface. 

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23.783 ................. Doors.

(a), (b), (c), (d) .... ...................................................................... 23.750 ........................................ Means of egress and emergency exits. 

(e), (f), (g) ............ ...................................................................... Means of Compliance.

23.785 ................. Seats, berths, litters, safety belts, and 

shoulder harnesses.

23.515 and 23.600 ..................... Special factors of safety, Emergency landing conditions. 

23.787 ................. Baggage and cargo compartments ............. 23.600(e) .................................... Emergency landing conditions. 

23.791 ................. Passenger information signs ....................... 23.755 ........................................ Occupant physical environment. 

23.803 ................. Emergency evacuation.

(a) ........................ ...................................................................... 23.750 ........................................ Means of egress and emergency exits. 

(b) ........................ ...................................................................... Means of Compliance.

23.805 ................. Flightcrew emergency exits ......................... 23.750 ........................................ Means of egress and emergency exits. 

23.807 ................. Emergency exits.

(a)(3), (b)(1), (c), 

(d)(1), (d)(4).

...................................................................... Means of Compliance.

Balance of 23.807 ...................................................................... 23.750 ........................................ Means of egress and emergency exits. 

23.811 ................. Emergency exit marking .............................. 23.750 ........................................ Means of egress and emergency exits. 

23.812 ................. Emergency lighting ...................................... 23.750 ........................................ Means of egress and emergency exits. 

23.813 ................. Emergency exit access.

(a) ........................ ...................................................................... 23.750 ........................................ Means of egress and emergency exits. 

(b) ........................ ...................................................................... Means of Compliance.

CS–VLA 853 ....... ...................................................................... 23.750 ........................................ Means of egress and emergency exits. 

23.815 ................. Width of aisle ............................................... 23.750 ........................................ Means of egress and emergency exits. 

23.831 ................. Ventilation .................................................... 23.755 ........................................ Occupant physical environment. 

23.841(a), (b)(6), 

(c) ,(d).

Pressurized cabins ...................................... 23.755 ........................................ Occupant physical environment. 

(b)(1) through (5) 

and (7).

...................................................................... Means of Compliance.

23.843 ................. Pressurization tests ..................................... 23.755 ........................................ Occupant physical environment. 

23.851 ................. Fire extinguishers.

(a) and (b) ........... ...................................................................... 23.800 ........................................ Fire protection outside designated fire 

zones. 

(c) ........................ ...................................................................... Means of Compliance.

23.853 ................. Passenger and crew compartment interiors.

(a) ........................ ...................................................................... 23.800 ........................................ Fire protection outside designated fire 

zones. 

(b)(c) and 

(d)(1)(2).

...................................................................... Means of Compliance.

(d)(3)(i), (d)(3)(iii), 

(d)(3)(iv).

...................................................................... 23.800 ........................................ Fire protection outside designated fire 

zones. 

(e) ........................ ...................................................................... 23.800 ........................................ Fire protection outside designated fire 

zones. 

(f) ......................... ...................................................................... 23.800 ........................................ Fire protection outside designated fire 

zones. 

23.855 ................. Cargo and baggage compartment fire protection.23.800 ........................................ Fire protection outside designated fire 

zones. 

23.856 ................. Thermal/acoustic insulation materials ......... 23.800 ........................................ Fire protection outside designated fire 

zones. 

23.859 ................. Combustion heater fire protection.

(a) ........................ ...................................................................... 23.800 ........................................ Fire protection outside designated fire 

zones. 

(b) thru (i) ............ ...................................................................... Means of Compliance.

23.863 ................. Flammable fluid fire protection.

(a) and (d) ........... ...................................................................... 23.800 ........................................ Fire protection outside designated fire 

zones. 

(b) and (c) ........... ...................................................................... Means of Compliance ................ Fire protection outside designated fire 

zones. 

23.865 ................. Fire protection of flight controls, engine 

mounts, and other flight structure.

23.805 ........................................ Fire protection in designated fire zones. 

23.867 ................. Electrical bonding and protection against 

lightning and static electricity.

(a) and (c) ........... ...................................................................... 23.810 ........................................ Lightning protection of structure. 

(b) ........................ ...................................................................... 23.1320 ...................................... Electrical and electronic system lightning 

protection. 

23.871 ................. Leveling means ........................................... Means of Compliance.

Subpart E—Powerplant 

23.901 ................. Installation ................................................... 23.900(c) .................................... Powerplant Installation. 

(a), (b), (f) ............ ...................................................................... 23.900(b).

(c) ........................ ...................................................................... 23.900(b).

(d) and (e) ........... ...................................................................... 23.900(b) .................................... Note: In addition to 900(b) these rules are 

covered under Part 33.63, 76, 77 and 

78. 

23.903 ................. Engines.

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(a) ........................ ...................................................................... 23.900(c).

(a)(2) ................... ...................................................................... 23.940(b) .................................... Powerplant ice protection. 

(b)(c) .................... ...................................................................... 23.910 and 23.920 ..................... Powerplant installation hazard assessment; 

Reversing systems. 

(b)(1) ................... ...................................................................... 23.405(d) .................................... Structural durability. 

(d) thru (g) ........... ...................................................................... 23.925 ........................................ Powerplant operational characteristics. 

23.904 ................. Automatic power reserve system ................ 23.915 ........................................ Automatic power control systems. 

23.905 ................. Propellers.

(a) ........................ ...................................................................... 23.910(a) .................................... Powerplant installation hazard assessment. 

(b), (d), (g) ........... ...................................................................... .................................................... Note: Intent covered under part 35. 

(c) ........................ ...................................................................... 23.905 ........................................ Propeller installation. 

(e) ........................ ...................................................................... 23.940 ........................................ Powerplant ice protection. 

(f) ......................... ...................................................................... 23.905 ........................................ Propeller installation. 

(h) ........................ ...................................................................... 23.910 ........................................ Powerplant installation hazard assessment. 

23.907 ................. Propeller vibration and fatigue .................... .................................................... Note: Intent covered under part 35. 

23.909 ................. Turbocharger systems.

(a) and (c) ........... ...................................................................... 23.900 ........................................ Powerplant installation. 

(b), (d), (e) ........... ...................................................................... 23.910 ........................................ Powerplant installation hazard assessment. 

23.925 ................. Propeller clearance ..................................... 23.905(c) .................................... Installation. 

23.929 ................. Engine installation ice protection ................ 23.940 ........................................ Powerplant ice protection. 

23.933 ................. Reversing systems ...................................... 23.920.

(a) ........................ ...................................................................... 23.920 ........................................ Reversing systems. 

(b) ........................ ...................................................................... 23.920 ........................................ Reversing systems. 

23.934 ................. Turbojet and turbofan engine thrust reverser systems tests.23.920 ........................................ Note: In addition to § 23.920, this rule is 

covered under § 33.97. 

23.937 ................. Turbopropeller-drag limiting systems .......... 23.920.

(a) ........................ ...................................................................... 23.920 ........................................ Reversing systems. 

(b) ........................ ...................................................................... 23.920 ........................................ Reversing systems. 

23.939 ................. Powerplant operating characteristics .......... 23.925 ........................................ In addition to 925 this rule is covered under 

Part 33, subpart D and F—Block Tests. 

23.943 ................. Negative acceleration .................................. 23.925 ........................................ Operational characteristics. 

23.951 ................. Fuel System—General ................................ 23.930(a)(3).

(a) and (b) ........... ...................................................................... 23.930(a)(3) ............................... Fuel systems. 

(c) ........................ ...................................................................... 23.930(a)(3).

(d) ........................ ...................................................................... 23.930(a)(3) ............................... Intent covered under Part 34. 

23.953 ................. Fuel system independence ......................... 23.930 ........................................ Fuel systems. 

23.954 ................. Fuel system lightning protection ................. 23.930 ........................................ Fuel systems. 

23.955 ................. Fuel flow ...................................................... 23.930 ........................................ Fuel systems. 

23.957 ................. Flow between interconnected tanks ............ 23.930(a)(7) ............................... Fuel systems. 

(a) ........................ ...................................................................... 23.930(a)(7).

(b) ........................ ...................................................................... 23.930(a)(7).

23.959 ................. Unusable fuel supply ................................... 23.930(c) .................................... Hazard assessment. 

23.961 ................. Fuel system hot weather operation ............. 23.930(a)(3) ............................... Fuel systems. 

23.963 ................. Fuel tank: general.

(a), (d), (e) ........... ...................................................................... 23.930(b)(4) ............................... Fuel systems. 

(b) and (c) ........... ...................................................................... 23.930(b)(6).

23.965 ................. Fuel tank tests ............................................. 23.930(b)(1).

23.967 ................. Fuel tank installation ................................... 23.930(b)(6).

23.969 ................. Fuel tank expansion space ......................... 23.930(b)(6).

23.971 ................. Fuel tank sump ............................................ 23.930(b)(6).

23.973 ................. Fuel tank filler connection ........................... 23.930(b)(6).

23.975 ................. Fuel tank vents and carburetor vapor vents 23.930(b)(6).

(a)(1) ................... ...................................................................... 23.940 ........................................ Powerplant ice protection. 

23.977 ................. Fuel tank outlet ............................................ 23.930(b)(6) ............................... Fuel systems. 

23.979 ................. Pressure fueling systems ............................ 23.930(d).

(a) and (b) ........... ...................................................................... 23.930(d) .................................... Fuel systems. 

(c) and (d) ........... ...................................................................... 23.930(d) .................................... Hazard assessment. 

23.991 ................. Fuel pumps .................................................. 23.930(a)(8).

(a), (b), (c) ........... ...................................................................... 23.930(a)(8) ............................... Fuel systems. 

(d) ........................ ...................................................................... 23.910 ........................................ Powerplant installation hazard assessment. 

23.993 ................. Fuel system lines and fittings ...................... 23.930.

23.994 ................. Fuel system components ............................ 23.930(a)(7) ............................... Hazard assessment. 

23.995 ................. Fuel valves and controls ............................. 23.930(d).

(a) ........................ ...................................................................... 23.930(d) .................................... Powerplant installation. 

(b) thru (g) ........... ...................................................................... 23.930(d).

23.997 ................. Fuel strainer or filter .................................... 23.930(a).

(a) thru (d) ........... ...................................................................... 23.930(a)(6) ............................... Fuel systems. 

(e) ........................ ...................................................................... 23.950 ........................................ Powerplant ice protection. 

23.999 ................. Fuel system drains ...................................... 23.930(a)(4) ............................... Fuel systems. 

23.1001 ............... Fuel jettisoning system ................................ 23.930(b)(5).

(a) ........................ ...................................................................... 23.930(b)(5) ............................... Fuel systems. 

(b) thru (g) ........... ...................................................................... 23.930(b)(5).

(h) ........................ ...................................................................... 23.910 ........................................ Powerplant installation hazard assessment. 

23.1011 ............... General ........................................................ 23.935 ........................................ Intent covered under Part 33. 

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23.1013 ............... Oil tanks ...................................................... 23.935(b)(1) ............................... Intent covered under Part 33. 

23.1015 ............... Oil tank tests ............................................... 23.935(b)(1) ............................... Intent covered under Part 33. 

23.1017 ............... Oil lines and fittings ..................................... 23.935(b)(1) ............................... Intent covered under Part 33. 

23.1019 ............... Oil strainer or filter ....................................... 23.935(b)(2) ............................... Intent covered under Part 33. 

23.1021 ............... Oil system drains ......................................... 23.935(b)(2) ............................... Intent covered under Part 33. 

23.1023 ............... Oil radiators ................................................. 23.935(b)(1) ............................... Intent covered under Part 33. 

23.1027 ............... Propeller feathering system ........................ 23.935(b)(2) ............................... Hazard assessment. 

23.1041 ............... Cooling—General ........................................ 23.940(a) .................................... Intent covered under Part 33. 

23.1043 ............... Cooling tests ................................................ 23.940(a) .................................... Intent covered under Part 33. 

23.1045 ............... Cooling test procedures for turbine engine 

powered airplanes.

23.940(a) .................................... Intent covered under Part 33. 

23.1047 ............... Cooling test procedures for reciprocating 

engine powered airplanes.

23.940(a) .................................... Intent covered under Part 33. 

23.1061 ............... Installation ................................................... 23.940(b) .................................... Intent covered under Part 33. 

23.1063 ............... Coolant tank tests ....................................... 23.940(b) .................................... Intent covered under Part 33. 

23.1091 ............... Air induction system .................................... 23.945(a) .................................... Intent covered under Part 33. 

23.1093 ............... Induction system icing protection ................ 23.940 ........................................ Powerplant ice protection. 

23.1095 ............... Carburetor deicing fluid flow rate ................ 23.940 ........................................ Powerplant ice protection. 

23.1097 ............... Carburetor deicing fluid system capacity .... 23.940 ........................................ Powerplant ice protection. 

23.1099 ............... Carburetor deicing fluid system detail design.23.940 ........................................ Powerplant ice protection. 

23.1101 ............... Induction air preheater design .................... 23.935.

(a) ........................ ...................................................................... 23.935 ........................................ Powerplant induction and exhaust systems. 

(b) and (c) ........... ...................................................................... 23.935.

23.1103 ............... Induction system ducts ................................ 23.935 ........................................ Powerplant induction and exhaust systems. 

23.1105 ............... Induction system screens ............................ 23.935.

23.1107 ............... Induction system filters ................................ 23.935 ........................................ Powerplant induction and exhaust systems. 

23.1109 ............... Turbocharger bleed air system ................... 23.910.

23.1111 ............... Turbine engine bleed air system ................. 23.910.

(a) and (c) ........... ...................................................................... 23.910 ........................................ Hazard assessment. 

(b) ........................ ...................................................................... 23.910.

23.1121 ............... Exhaust System—General .......................... 23.935.

(a) thru (g) ........... ...................................................................... 23.935 ........................................ Powerplant induction and exhaust systems. 

(h) ........................ ...................................................................... 23.910 ........................................ Hazard assessment. 

23.1123 ............... Exhaust system ........................................... 23.910 ........................................ Hazard assessment. 

23.1125 ............... Exhaust heat exchangers ............................ 23.910.

(a) ........................ ...................................................................... 23.910 ........................................ Hazard assessment. 

(b) ........................ ...................................................................... 23.910.

23.1141 ............... Powerplant controls: general (a)(c)(g) ........ 23.1505(b).

............................. (b)(d)(e) and (f) ............................................ 23.910 ........................................ Powerplant installation hazard assessment. 

23.1142 ............... Auxiliary power unit controls ....................... 23.1500(b).

23.1143 ............... Engine controls ............................................ 23.1500(b).

23.1145 ............... Ignition switches .......................................... 23.1500(b).

23.1147 ............... Mixture controls ........................................... 23.1500(b).

23.1149 ............... Propeller speed and pitch controls ............. 23.1500(b).

23.1153 ............... Propeller feathering controls ....................... 23.1500(b).

23.1155 ............... Turbine engine reverse thrust and propeller 

pitch settings below the flight regime.

23.910 and 23.1500(b) .............. Hazard assessment. 

23.1157 ............... Carburetor air temperature controls ............ 23.1500(b).

23.1163 ............... Powerplant accessories .............................. 23.910(a) .................................... Powerplant installation hazard assessment. 

(a), (c), (e) ........... ...................................................................... 23.910(a).

(b) and (d) ........... ...................................................................... 23.910(a).

23.1165 ............... Engine ignition systems .............................. Means of Compliance.

23.1181 ............... Designated fire zones: regions included ..... 23.1000(a) .................................. Powerplant fire protection. 

23.1182 ............... Nacelle areas behind firewalls .................... 23.1000(b).

23.1183 ............... Lines, fittings, and components .................. 23.1000(b).

23.1189 ............... Shutoff means ............................................. 23.1000(c).

23.1191 ............... Firewalls ...................................................... 23.1000(d).

(a) thru (e), (g), 

(h).

...................................................................... 23.1000(d).

(f) ......................... ...................................................................... 23.910 ........................................ Powerplant installation hazard assessment. 

23.1192 ............... Engine accessory compartment diaphragm 23.1000(d).

23.1193 ............... Cowling and nacelle .................................... 23.1000(d).

(a) thru (e) ........... ...................................................................... 23.1000(d).

(f) and (g) ............ ...................................................................... 23.1000(d) .................................. Hazard assessment. 

23.1195 ............... Fire extinguishing systems .......................... 23.1000(e).

23.1197 ............... Fire extinguishing agents ............................ 23.1000(e).

23.1199 ............... Extinguishing agent containers ................... 23.1000(e).

23.1201 ............... Fire extinguishing system materials ............ 23.1000(e).

(a) ........................ ...................................................................... 23.1000(e) .................................. Hazard assessment. 

(b) ........................ ...................................................................... 23.1000(e).

23.1203 ............... Fire detector system .................................... 23.1000(f).

(a), (d), (e) ........... ...................................................................... 23.1000(f).

(b) and (c) ........... ...................................................................... 23.1000(f) ................................... Hazard assessment. 

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Current section Title Proposed section Proposed title 

Subpart F—Equipment 

23.1301 ............... Function and installation.

(a) ........................ ...................................................................... 23.1300(a) and 23.1305(a) ........ Airplane level systems requirements; Function and installation. 

(b) ........................ ...................................................................... 23.1305(a)(3) ............................. Function and installation. 

(c) ........................ ...................................................................... 23.1305(a)(2) ............................. Function and installation. 

23.1303 ............... Flight and navigation instruments ............... 23.1300, 23.1310, 23.1305(b) 

and (c), and 23.1330(c).

Airplane level systems requirements; Flight, 

navigation, and powerplant instruments; 

Function and installation; System power 

generation, storage, and distribution. 

23.1305 ............... Powerplant instruments ............................... 23.1300, 23.1310 and 

23.1305(c).

Airplane level systems requirements; Flight, 

navigation, and powerplant instruments; 

Function and installation. 

23.1306 ............... Electrical and electronic system lightning 

protection.

23.1320 ...................................... Electrical and electronic system lightning 

protection. 

23.1307 ............... Miscellaneous equipment ............................ 23.1300 and 23.1310 ................. Airplane level systems requirements; Flight, 

navigation, and powerplant instruments. 

23.1308 ............... High-Intensity Radiated Fields (HIRF) protection.23.1325 ...................................... High-intensity Radiated Fields (HIRF) protection. 

23.1309 ............... Equipment, systems, and installations ........ 23.1315 ...................................... Equipment, systems, and installations. 

(a)(1) ................... ...................................................................... 23.1300(a) .................................. Airplane level systems requirements. 

(a)(2) ................... ...................................................................... 23.1300(b) .................................. Airplane level systems requirements. 

(b) ........................ ...................................................................... .................................................... —Deleted—. 

(c) ........................ ...................................................................... 23.1315(b) .................................. Equipment, systems, and installations. 

(b) ........................ ...................................................................... 23.1305(c) .................................. Function and installation. 

23.1310 ............... Power source capacity and distribution ...... 23.1330 ...................................... System power generation, storage, and 

distribution. 

23.1311 ............... Electronic display instrument systems ........ 23.1300 and 23.1310 ................. Airplane level systems requirements; Flight, 

navigation, and powerplant instruments. 

23.1321 ............... Arrangement and visibility ........................... 23.1300 and 23.1310 ................. Airplane level systems requirements; Flight, 

navigation, and powerplant instruments. 

23.1322 ............... Warning, caution, and advisory lights ......... 23.1305(b) and (c) ..................... Flight, navigation, and powerplant instruments. 

23.1323 ............... Airspeed indicating system ......................... 23.1300, 23.1305, 23.1310, and 

1315.

Airplane level systems requirements; Function and installation; Flight, navigation, 

and powerplant instruments; and Equipment, systems, and installations. 

(d) ........................ ...................................................................... 23.1405 ...................................... Flight in icing conditions. 

23.1325 ............... Static pressure system ................................ 23.1300, 23.1310, and 23.1315 Airplane level systems requirements; Flight, 

navigation, and powerplant instruments; 

and Equipment, systems, and installations. 

(b)(3) and (g) ....... ...................................................................... 1405 ........................................... Flight in icing conditions. 

23.1326 ............... Pitot heat indication systems ...................... 23.1305 ...................................... Function and installation. 

23.1327 ............... Magnetic direction indicator ........................ 23.1300, 23.1305 and 23.1310 .. Airplane level systems requirements; Function and installation; Flight, navigation, 

and powerplant instruments. 

23.1329 ............... Automatic pilot system ................................ 23.1300, 23.1305 and 23.1315 .. Airplane level systems requirements; Function and installation; Equipment, systems, and installations. 

(a) ........................ ...................................................................... 23.1300 and 23.1315 ................. Airplane level systems requirements; 

Equipment, systems, and installations. 

(b) ........................ ...................................................................... 23.700 and 23.1500 ................... Flight control systems; Flightcrew interface. 

(c) ........................ ...................................................................... 23.1305 ...................................... Function and installation. 

(d) ........................ ...................................................................... 23.700 and 23.1500 ................... Flight control systems; Flightcrew interface. 

(e), (f), (g) ............ ...................................................................... 23.1300 and 23.1315 ................. Airplane level systems requirements; 

Equipment, systems, and installations. 

(h) ........................ ...................................................................... 23.1305 ...................................... Function and installation. 

23.1331 ............... Instruments using a power source.

(a) ........................ ...................................................................... 23.1305(c) .................................. Function and installation. 

(b) ........................ ...................................................................... 23.1315(b) and 23.1330(b) ........ Equipment, systems, and installations; System power generation, storage, and distribution. 

(c) ........................ ...................................................................... 23.1310(b) .................................. Flight, navigation, and powerplant instruments. 

23.1335 ............... Flight director systems ................................ 23.1300, 23.1305, 23.1315, and 

23.1500.

Airplane level systems; Function and installation; Equipment systems and installations; and Flightcrew interface. 

23.1337 ............... Powerplant instruments installation.

(a) ........................ ...................................................................... 23.800(g) .................................... Fire protection outside designated fire 

zones. 

23.930 ........................................ Fuel systems. 

(b) ........................ ...................................................................... 23.1305(c) and (d) ..................... Function and installation. 

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23.1310(a) .................................. Flight, navigation, and powerplant instruments. 

23.1315(b) .................................. Equipment, systems, and installations. 

(c) ........................ ...................................................................... 23.1315(b) .................................. Equipment, systems, and installations. 

(d) ........................ ...................................................................... 23.1305(c) .................................. Function and installation. 

23.1310(a) .................................. Flight, navigation, and powerplant instruments. 

23.1351 ............... Electrical Systems—General ....................... 23.1300 ...................................... Airplane level systems requirements. 

23.1305 ...................................... Function and installation. 

23.1315 ...................................... Equipment, systems, and installations. 

23.1330 ...................................... System power generation, storage, and 

distribution. 

23.1353 ............... Storage battery design and installation ....... 23.1300 ...................................... Airplane level systems requirements. 

23.1305 ...................................... Function and installation. 

23.1315 ...................................... Equipment, systems, and installations. 

23.1330 ...................................... System power generation, storage, and 

distribution. 

23.1357 ............... Circuit protective devices ............................ 23.1300 ...................................... Airplane level systems requirements. 

23.1305 ...................................... Function and installation. 

23.1315 ...................................... Equipment, systems, and installations. 

23.1330 ...................................... System power generation, storage, and 

distribution. 

23.1359 ............... Electrical system fire protection.

(a) ........................ ...................................................................... Means of Compliance.

(b) ........................ ...................................................................... 805 ............................................. Flammability in designated fire zones. 

(c) ........................ ...................................................................... 800 ............................................. Fire protection outside designated fire 

zones. 

23.1361 ............... Master switch arrangement ......................... 23.1300 and 23.1305 ................. Airplane level systems requirements; Function and installation. 

23.1365 ............... Electrical cables and equipment ................. 23.1305 ...................................... Function and installation. 

(b) ........................ ...................................................................... 23.805 ........................................ Flammability in designated fire zones. 

(a), (c) thru (f) ..... ...................................................................... Means of Compliance.

23.1367 ............... Switches.

(a) and (b) ........... ...................................................................... 23.1305 ...................................... Function and installation. 

(c) and (d) ........... ...................................................................... 23.1500 ...................................... Flightcrew interface. 

23.1381 ............... Instrument lights.

(a) and (b) ........... ...................................................................... 23.1500 ...................................... Flightcrew interface. 

(c) ........................ ...................................................................... 23.1335 ...................................... External and cockpit lighting. 

23.1383(a), (b), 

(c).

Taxi and landing lights ................................ 23.1335 ...................................... External and cockpit lighting. 

(d) ........................ Taxi and landing lights ................................ 23.800 ........................................ Fire protection outside designated fire 

zones. 

23.1385(a), (b), 

(c).

Position light system installation ................. 23.1335 ...................................... External and cockpit lighting. 

(d) ........................ Position light system installation ................. 23.800 ........................................ Fire protection outside designated fire 

zones. 

23.1387 ............... Position light system dihedral angles .......... 23.1335 ...................................... External and cockpit lighting. 

23.1389 ............... Position light distribution and intensities ..... 23.1335 ...................................... External and cockpit lighting. 

23.1391 ............... Minimum intensities in the horizontal plane 

of position lights.

23.1335 ...................................... External and cockpit lighting. 

23.1393 ............... Minimum intensities in any vertical plane of 

position lights.

23.1335 ...................................... External and cockpit lighting. 

23.1395 ............... Maximum intensities in overlapping beams 

of position lights.

23.1335 ...................................... External and cockpit lighting. 

23.1397 ............... Color specifications ..................................... 23.1335 ...................................... External and cockpit lighting. 

23.1399 ............... Riding light ................................................... 23.1335 ...................................... External and cockpit lighting. 

23.1401 ............... Anticollision light system.

(a), (a)(1) ............. ...................................................................... 23.1335 ...................................... External and cockpit lighting. 

(a)(2) ................... ...................................................................... Means of Compliance.

(b) thru (f) ............ ...................................................................... 23.1335 ...................................... External and cockpit lighting. 

23.1411 ............... Safety Equipment-General.

(a), (b)(1) ............. ...................................................................... 23.1400 ...................................... Safety equipment. 

(b)(2) ................... ...................................................................... 23.600 ........................................ Emergency conditions. 

23.1415 ............... Ditching equipment ...................................... 23.1400 ...................................... Safety equipment. 

(a), (c), (d) ........... ...................................................................... 23.1400 ...................................... Safety equipment. 

(b) ........................ ...................................................................... Means of Compliance.

23.1416 ............... Pneumatic de-icer boot system ................... 23.1300 ...................................... Airplane level systems requirements. 

............................. ...................................................................... 23.1305 ...................................... Function and installation. 

23.1419 ............... Ice protection ............................................... 23.230 ........................................ Flight in icing conditions. 

23.1405 ...................................... Performance and flight characteristics requirements for flight in icing conditions. 

23.1431 ............... Electronic equipment ................................... 23.1315 ...................................... Equipment, systems and installations. 

23.1435 ............... Hydraulic systems.

(a)(4) and (b) ....... ...................................................................... 23.1410 ...................................... Pressurized system elements. 

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Current section Title Proposed section Proposed title 

(a), (a)(1) through 

(3), (c).

...................................................................... Means of Compliance.

23.1437 ............... Accessories for multiengine airplanes ........ 23.1410 ...................................... Pressurized system elements. 

23.1438 ............... Pressurization and pneumatic systems.

(a), (b) ................. ...................................................................... 23.1410 ...................................... Pressurized system elements. 

(c) ........................ ...................................................................... Means of Compliance.

23.1410(e) .................................. Pressurized system elements. 

23.1441 ............... Oxygen equipment and supply.

(a) ........................ ...................................................................... Means of Compliance.

(b) ........................ ...................................................................... 23.1315 ...................................... Equipment, systems and installation. 

(c), (d), (e) ........... ...................................................................... 23.755 ........................................ Occupant physical environment. 

23.1443(a), (b), 

(c).

Minimum mass flow of supplemental oxygen.23.755 ........................................ Occupant physical environment. 

(d) ........................ ...................................................................... Definition.

23.1445 ............... Oxygen distribution system ......................... 23.755 ........................................ Occupant physical environment. 

23.1447 ............... Equipment standards for oxygen dispensing units.

(a), (b), (c), (d), (f) ...................................................................... 23.755 ........................................ Occupant physical environment. 

(e) ........................ ...................................................................... Means of Compliance.

23.1449 ............... Means for determining use of oxygen ........ 23.755 ........................................ Occupant physical environment. 

23.1450 ............... Chemical oxygen generators.

(a) ........................ ...................................................................... Means of Compliance.

(b) ........................ ...................................................................... 23.1315 ...................................... Equipment, systems and installation. 

(c) ........................ ...................................................................... 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1451 ............... Fire protection for oxygen equipment ......... 23.1315 ...................................... Equipment, systems and installation. 

23.1453 ............... Protection of oxygen equipment from rupture.23.1315 ...................................... Equipment, systems and installation. 

23.1457 ............... Cockpit voice recorders ............................... 23.1457 ...................................... No Change. 

23.1459 ............... Flight recorders.

(a)(1) ................... ...................................................................... 23.1459 ...................................... Flight data recorders. 

(a)(2) thru (d) ...... ...................................................................... 23.1459 ...................................... No Change. 

23.1461 ............... Equipment containing high energy rotors ... 23.755 ........................................ Occupant physical environment. 

Subpart G—Operating Limitations and Information 

23.1501 ............... General ........................................................ 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1505 ............... Airspeed limitations ..................................... 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1507 ............... Operating maneuvering speed .................... 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1511 ............... Flap extended speed ................................... 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1513 ............... Minimum control speed ............................... 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1519 ............... Weight and center of gravity ....................... 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1521 ............... Powerplant limitations ................................. 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1522 ............... Auxiliary power unit limitations .................... 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1523 ............... Minimum flight crew .................................... 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1524 ............... Maximum passenger seating configuration 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1525 ............... Kinds of operation ....................................... 23.1300 ...................................... Airplane level system requirements. 

23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1527 ............... Maximum operating altitude ........................ 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1529 ............... Instructions for continued airworthiness ...... 23.1515 ...................................... Instructions for continued airworthiness. 

23.1541 ............... Marking and Placards—General ................. 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1543 ............... Instrument marking: general ....................... 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1545 ............... Airspeed indicator ........................................ 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1547 ............... Magnetic direction indicator ........................ 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1549 ............... Powerplant and auxiliary power unit instruments.23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1551 ............... Oil quantity indicator .................................... 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

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Current section Title Proposed section Proposed title 

23.1553 ............... Fuel quantity indicator ................................. 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1555 ............... Control markings ......................................... 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1557 ............... Miscellaneous marking and placards .......... 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1559 ............... Operating limitations placard ....................... 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1561 ............... Safety equipment ........................................ 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1563 ............... Airspeed placards ........................................ 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1567 ............... Flight maneuver placard .............................. 23.1505 ...................................... Instrument markings, control markings, and 

placards. 

23.1581 ............... Airplane Flight Manual and Approved Manual Material—General.23.1510 ...................................... Airplane flight manual. 

23.1583 ............... Operating limitations .................................... 23.1510 ...................................... Airplane flight manual. 

23.1585 ............... Operating procedures .................................. 23.1510 ...................................... Airplane flight manual. 

23.1587 ............... Performance information ............................. 23.1510 ...................................... Airplane flight manual. 

23.1589 ............... Loading information ..................................... 23.1510 ...................................... Airplane flight manual. 

Appendix A .......... Simplified Design Load Criteria ................... Means of Compliance.

Appendix B .......... [Reserved] ................................................... .................................................... —Deleted— 

Appendix C ......... Basic Landing Conditions ............................ Means of Compliance.

Appendix D ......... Wheel Spin-Up and Spring-Back Loads ..... Means of Compliance.

Appendix E .......... [Reserved] ................................................... .................................................... —Deleted— 

Appendix F .......... Test Procedure ............................................ Means of Compliance.

Appendix G ......... Instructions for Continued Airworthiness .... Appendix A ................................. Instructions for Continued Airworthiness. 

Appendix H ......... Installation of An Automatic Power Reserve 

(APR) System.

Means of Compliance.

Appendix I ........... Seaplane Loads .......................................... Means of Compliance.

Appendix J .......... HIRF Environments and Equipment HIRF 

Test Levels.

Means of Compliance.

Appendix 2 to the Preamble— 

Abbreviations and Acronyms 

Frequently Used in This Document 

AD Airworthiness Directive 

AFM Airplane Flight Manual 

ARC Aviation Rulemaking Committee 

ASTM ASTM International 

CAA Civil Aviation Authority 

CAR Civil Aviation Regulations 

Cf Confer (to identify a source or a 

usage citation for a word or phrase) 

CPS Certification Process Study 

CS Certification Specification 

CS–VLA Certification Specification— 

Very Light Aeroplanes 

EASA European Aviation Safety 

Agency 

ELOS Equivalent Level of Safety 

FR Federal Register 

GA General Aviation 

HIRF High-Intensity Radiated Field 

IFR Instrument Flight Rules 

KCAS Knots Calibrated Airspeeds 

LOC Loss of Control 

NPRM Notice of Proposed Rulemaking 

NTSB National Transportation Safety 

Board 

OMB Office of Management and 

Budget 

SAE SAE International 

SLD Supercooled Large Droplet 

TCDS Type Certificate Data Sheet 

VA Design Maneuvering Speed 

VC Design Cruising Speed 

VD Design Dive Speed 

VMC Minimum Control Speed 

VMO/MMO Maximum Operating Limit 

Speed 

VFR Visual Flight Rules 

VSO Stalling speed or the minimum 

steady flight speed in the landing 

configuration 

List of Subjects 

14 CFR Part 21 

Aircraft, Aviation safety, Recording 

and recordkeeping requirements. 

14 CFR Part 23 

Aircraft, Aviation Safety, Signs and 

symbols. 

14 CFR Part 35 

Aircraft, Aviation safety. 

14 CFR Part 43 

Aircraft, Aviation safety, Reporting 

and recordkeeping requirements. 

14 CFR Part 91 

Air traffic control, Aircraft, Airmen, 

Airports, Aviation safety, Reporting and 

recordkeeping requirements. 

14 CFR Part 121 

Aircraft, Airmen, Aviation safety, 

Reporting and recordkeeping 

requirements. 

14 CFR Part 135 

Aircraft, Airmen, Aviation safety, 

Reporting and recordkeeping 

requirements. 

The Proposed Amendment 

In consideration of the foregoing, the 

Federal Aviation Administration 

proposes to amend chapter I of title 14, 

Code of Federal Regulations as follows: 

PART 21—CERTIFICATION 

PROCEDURES FOR PRODUCTS AND 

ARTICLES 

■ 1. The authority citation for part 21 is 

revised to read as follows: 

Authority: 42 U.S.C. 7572; 49 U.S.C. 106(f), 

106(g), 40105, 40113, 44701–44702, 44704, 

44707, 44709, 44711, 44713, 44715, 45303. 

■ 2. In § 21.9, revise paragraphs (a)(5), 

(a)(6), (b), and (c) introductory text, and 

add paragraph (a)(7) to read as follows: 

§ 21.9 Replacement and modification 

articles. 

(a) * * * 

(5) Produced by an owner or operator 

for maintaining or altering that owner or 

operator’s product; 

(6) Fabricated by an appropriately 

rated certificate holder with a quality 

system, and consumed in the repair or 

alteration of a product or article in 

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accordance with part 43 of this chapter; 

or 

(7) Produced in any other manner 

approved by the FAA. 

(b) Except as provided in paragraphs 

(a)(1), (a)(2) and (a)(7) of this section, a 

person who produces a replacement or 

modification article for sale may not 

represent that part as suitable for 

installation on a type-certificated 

product. 

(c) Except as provided in paragraphs 

(a)(1), (a)(2) and (a)(7) of this section, a 

person may not sell or represent an 

article as suitable for installation on an 

aircraft type-certificated under 

§ 21.25(a)(2) or § 21.27 unless that 

article— 

* * * * * 

■ 3. In § 21.17, revise paragraph (a) 

introductory text to read as follows: 

§ 21.17 Designation of applicable 

regulations. 

(a) Except as provided in §§ 25.2, 

27.2, 29.2, and in parts 26, 34, and 36 

of this subchapter, an applicant for a 

type certificate must show that the 

aircraft, aircraft engine, or propeller 

concerned meets— 

* * * * * 

■ 4. In § 21.24, revise paragraph (a)(1)(i) 

to read as follows: 

§ 21.24 Issuance of type certificate: 

primary category aircraft. 

(a) * * * 

(1) * * * 

(i) Is unpowered; is an airplane 

powered by a single, naturally aspirated 

engine with a 61-knot or less Vso stall 

speed as defined in § 23.49 of this 

chapter, at amendment 23–62, effective 

on Jan 31, 2012; or is a rotorcraft with 

a 6-pound per square foot main rotor 

disc loading limitation, under sea level 

standard day conditions; 

* * * * * 

■ 5. In § 21.35, revise paragraph (b)(2) to 

read as follows: 

§ 21.35 Flight tests. 

* * * * * 

(b) * * * 

(2) For aircraft to be certificated under 

this subchapter, except gliders, and 

except for low-speed airplanes, as 

defined in part 23 of this chapter, of 

6,000 pounds or less maximum weight 

that are to be certificated under part 23 

of this chapter, to determine whether 

there is reasonable assurance that the 

aircraft, its components, and its 

equipment are reliable and function 

properly. 

* * * * * 

■ 6. In § 21.50, revise paragraph (b) to 

read as follows: 

§ 21.50 Instructions for continued 

airworthiness and manufacturer’s 

maintenance manuals having airworthiness 

limitations sections. 

* * * * * 

(b) The holder of a design approval, 

including either a type certificate or 

supplemental type certificate for an 

aircraft, aircraft engine, or propeller for 

which application was made after 

January 28, 1981, must furnish at least 

one set of complete Instructions for 

Continued Airworthiness to the owner 

of each type aircraft, aircraft engine, or 

propeller upon its delivery, or upon 

issuance of the first standard 

airworthiness certificate for the affected 

aircraft, whichever occurs later. The 

Instructions for Continued 

Airworthiness must be prepared in 

accordance with §§ 23.1515, 25.1529, 

25.1729, 27.1529, 29.1529, 31.82, 33.4, 

35.4, or part 26 of this subchapter, or as 

specified in the applicable 

airworthiness criteria for special classes 

of aircraft defined in § 21.17(b), as 

applicable. If the holder of a design 

approval chooses to designate parts as 

commercial, it must include in the 

Instructions for Continued 

Airworthiness a list of commercial parts 

submitted in accordance with the 

provisions of paragraph (c) of this 

section. Thereafter, the holder of a 

design approval must make those 

instructions available to any other 

person required by this chapter to 

comply with any of the terms of those 

instructions. In addition, changes to the 

Instructions for Continued 

Airworthiness shall be made available 

to any person required by this chapter 

to comply with any of those 

instructions. 

* * * * * 

■ 7. In § 21.101 revise paragraphs (b) 

introductory text, and (c) to read as 

follows: 

§ 21.101 Designation of applicable 

regulations. 

* * * * * 

(b) Except as provided in paragraph 

(g) of this section, if paragraphs (b)(1), 

(2), or (3) of this section apply, an 

applicant may show that the change and 

areas affected by the change comply 

with an earlier amendment of a 

regulation required by paragraph (a) of 

this section, and of any other regulation 

the FAA finds is directly related. 

However, the earlier amended 

regulation may not precede either the 

corresponding regulation incorporated 

by reference in the type certificate, or 

any regulation in §§ 25.2, 27.2, or § 29.2 

of this chapter that is related to the 

change. The applicant may show 

compliance with an earlier amendment 

of a regulation for any of the following: 

* * * * * 

(c) An applicant for a change to an 

aircraft (other than a rotorcraft) of 6,000 

pounds or less maximum weight, to a 

non-turbine rotorcraft of 3,000 pounds 

or less maximum weight, to a simple, to 

a level 1 low speed, or to a level 2 low 

speed airplane may show that the 

change and areas affected by the change 

comply with the regulations 

incorporated by reference in the type 

certificate. However, if the FAA finds 

that the change is significant in an area, 

the FAA may designate compliance 

with an amendment to the regulation 

incorporated by reference in the type 

certificate that applies to the change and 

any regulation that the FAA finds is 

directly related, unless the FAA also 

finds that compliance with that 

amendment or regulation would not 

contribute materially to the level of 

safety of the product or would be 

impractical. 

* * * * * 

■ 8. Revise part 23 to read as follows: 

PART 23—AIRWORTHINESS 

STANDARDS: NORMAL CATEGORY 

AIRPLANES 

Sec. 

Subpart A—General 

23.1 Applicability and definitions. 

23.5 Certification of normal category 

airplanes. 

23.10 Accepted means of compliance. 

Subpart B—Flight 

Performance 

23.100 Weight and center of gravity. 

23.105 Performance data. 

23.110 Stall speed. 

23.115 Takeoff performance. 

23.120 Climb requirements. 

23.125 Climb information. 

23.130 Landing. 

Flight Characteristics 

23.200 Controllability. 

23.205 Trim. 

23.210 Stability. 

23.215 Stall characteristics, stall warning, 

and spins. 

23.220 Ground and water handling 

characteristics. 

23.225 Vibration, buffeting, and high-speed 

characteristics. 

23.230 Performance and flight 

characteristics requirements for flight in 

icing conditions. 

Subpart C—Structures 

23.300 Structural design envelope. 

23.305 Interaction of systems and 

structures. 

Structural Loads 

23.310 Structural design loads. 

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23.315 Flight load conditions. 

23.320 Ground and water load conditions. 

23.325 Component loading conditions. 

23.330 Limit and ultimate loads. 

Structural Performance 

23.400 Structural strength. 

23.405 Structural durability. 

23.410 Aeroelasticity. 

Design 

23.500 Structural design. 

23.505 Protection of structure. 

23.510 Materials and processes. 

23.515 Special factors of safety. 

Structural Occupant Protection 

23.600 Emergency conditions. 

Subpart D—Design and Construction 

23.700 Flight control systems. 

23.705 Landing gear systems. 

23.710 Buoyancy for seaplanes and 

amphibians. 

Occupant System Design Protection 

23.750 Means of egress and emergency 

exits. 

23.755 Occupant physical environment. 

Fire and High Energy Protection 

23.800 Fire protection outside designated 

fire zones. 

23.805 Fire protection in designated fire 

zones. 

23.810 Lightning protection of structure. 

Subpart E—Powerplant 

23.900 Powerplant installation. 

23.905 Propeller installation. 

23.910 Powerplant installation hazard 

assessment. 

23.915 Automatic power control systems. 

23.920 Reversing systems. 

23.925 Powerplant operational 

characteristics. 

23.930 Fuel system. 

23.935 Powerplant induction and exhaust 

systems. 

23.940 Powerplant ice protection. 

23.1000 Powerplant fire protection. 

Subpart F—Equipment 

23.1300 Airplane level systems 

requirements. 

23.1305 Function and installation. 

23.1310 Flight, navigation, and powerplant 

instruments. 

23.1315 Equipment, systems, and 

installations. 

23.1320 Electrical and electronic system 

lightning protection. 

23.1325 High-intensity Radiated Fields 

(HIRF) protection. 

23.1330 System power generation, storage, 

and distribution. 

23.1335 External and cockpit lighting. 

23.1400 Safety equipment. 

23.1405 Flight in icing conditions. 

23.1410 Pressurized system elements. 

23.1457 Cockpit voice recorders. 

23.1459 Flight data recorders. 

Subpart G—Flightcrew Interface and Other 

Information 

23.1500 Flightcrew interface. 

23.1505 Instrument markings, control 

markings and placards. 

23.1510 Airplane flight manual. 

23.1515 Instructions for continued 

airworthiness. 

Appendix A to Part 23—Instructions for 

Continued Airworthiness 

Authority: 49 U.S.C. 106(f), 106(g), 40113, 

44701–44702, 44704, Pub. L. 113–53, 127 

Stat. 584 (49 U.S.C. 44704) note. 

Subpart A—General 

§ 23.1 Applicability and definitions. 

(a) This part prescribes airworthiness 

standards for the issuance of type 

certificates, and changes to those 

certificates, for airplanes in the normal 

category. 

(b) For the purposes of this part, the 

following definitions apply: 

(1) Continued safe flight and landing 

means an airplane is capable of 

continued controlled flight and landing, 

possibly using emergency procedures, 

without requiring exceptional pilot skill 

or strength. Upon landing, some 

airplane damage may occur as a result 

of a failure condition. 

(2) Designated fire zone means a zone 

where catastrophic consequences from 

fire in that zone must be mitigated by 

containing the fire in that zone. 

(3) Empty weight means the weight of 

the airplane with fixed ballast, unusable 

fuel, full operating fluids, and other 

fluids required for normal operation of 

airplane systems. 

§ 23.5 Certification of normal category 

airplanes. 

(a) Certification in the normal 

category applies to airplanes with a 

passenger-seating configuration of 19 or 

less and a maximum certificated takeoff 

weight of 19,000 pounds or less. 

(b) Airplane certification levels are: 

(1) Level 1—for airplanes with a 

maximum seating configuration of 0 to 

1 passengers. 

(2) Level 2—for airplanes with a 

maximum seating configuration of 2 to 

6 passengers. 

(3) Level 3—for airplanes with a 

maximum seating configuration of 7 to 

9 passengers. 

(4) Level 4—for airplanes with a 

maximum seating configuration of 10 to 

19 passengers. 

(c) Airplane performance levels are: 

(1) Low speed—for airplanes with a 

VC or VMO ≤ 250 Knots Calibrated 

Airspeed (KCAS) (and MMO ≤ 0.6). 

(2) High speed—for airplanes with a 

VC or VMO > 250 KCAS (or MMO > 0.6). 

(d) Simple—Simple is defined as a 

level 1 airplane with a VC or VMO ≤ 250 

KCAS (and MMO ≤ 0.6), a VSO ≤ 45 

KCAS and approved only for VFR 

operations. 

(e) Airplanes not certified for 

aerobatics may be used to perform any 

maneuver incident to normal flying, 

including— 

(1) Stalls (except whip stalls); and 

(2) Lazy eights, chandelles, and steep 

turns, in which the angle of bank is not 

more than 60 degrees. 

(f) Airplanes certified for aerobatics 

may be used to perform maneuvers 

without limitations, other than those 

limitations necessary to avoid damage 

or injury. 

§ 23.10 Accepted means of compliance. 

(a) An applicant must show the FAA 

how it will demonstrate compliance 

with this part using a means of 

compliance, which may include 

consensus standards, accepted by the 

Administrator. 

(b) A person requesting acceptance of 

a means of compliance must provide the 

means of compliance to the FAA in a 

form and manner specified by the 

Administrator. 

Subpart B—Flight 

Performance 

§ 23.100 Weight and center of gravity. 

(a) The applicant must determine 

weights and centers of gravity that 

provide limits for the safe operation of 

the airplane. 

(b) The applicant must show 

compliance with each requirement of 

this subpart at each combination of 

weight and center of gravity within the 

airplane’s range of loading conditions 

using tolerances acceptable to the 

Administrator. 

(c) The condition of the airplane at 

the time of determining its empty 

weight and center of gravity must be 

well defined and easily repeatable. 

§ 23.105 Performance data. 

(a) Unless otherwise prescribed, an 

airplane must meet the performance 

requirements of this subpart in— 

(1) Still air and standard atmospheric 

conditions at sea level for all airplanes; 

and 

(2) Ambient atmospheric conditions 

within the operating envelope for— 

(i) Level 1 high-speed and level 2 

high-speed airplanes; and 

(ii) Levels 3 and 4 airplanes. 

(b) Unless otherwise prescribed, the 

applicant must develop the performance 

data required by this subpart for the 

following conditions: 

(1) Airport altitudes from sea level to 

10,000 feet (3,048 meters); and 

(2) Temperatures from standard to 30° 

Celsius above standard or the maximum 

ambient atmospheric temperature at 

which compliance with propulsion 

cooling requirements in climb is shown, 

if lower. 

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(c) The procedures used for 

determining takeoff and landing 

distances must be executable 

consistently by pilots of average skill in 

atmospheric conditions expected to be 

encountered in service. 

(d) Performance data determined in 

accordance with paragraph (b) of this 

section must account for losses due to 

atmospheric conditions, cooling needs, 

and other demands on power sources. 

§ 23.110 Stall speed. 

The applicant must determine the 

airplane stall speed or the minimum 

steady flight speed for each flight 

configuration used in normal 

operations, including takeoff, climb, 

cruise, descent, approach, and landing. 

Each determination must account for 

the most adverse conditions for each 

flight configuration with power set at 

idle or zero thrust. 

§ 23.115 Takeoff performance. 

(a) The applicant must determine 

airplane takeoff performance accounting 

for— 

(1) Stall speed safety margins; 

(2) Minimum control speeds; and 

(3) Climb gradients. 

(b) For all airplanes, takeoff 

performance includes the determination 

of ground roll and initial climb distance 

to 50 feet (15 meters) above the takeoff 

surface. 

(c) For levels 1, 2, and 3 high-speed 

multiengine airplanes, multiengine 

airplanes with a maximum takeoff 

weight greater than 12,500 pounds and 

level 4 multiengine airplanes, takeoff 

performance includes a determination 

the following distances after a sudden 

critical loss of thrust: 

(1) Accelerate-stop; 

(2) Ground roll and initial climb to 50 

feet (15 meters) above the takeoff 

surface; and 

(3) Net takeoff flight path. 

§ 23.120 Climb requirements. 

The applicant must demonstrate the 

following minimum climb performance 

out of ground effect: 

(a) With all engines operating and in 

the initial climb configuration— 

(1) For levels 1 and 2 low speed 

airplanes, a climb gradient at sea level 

of 8.3 percent for landplanes and 6.7 

percent for seaplanes and amphibians; 

and 

(2) For levels 1 and 2 high-speed 

airplanes and all level 3 airplanes, a 

climb gradient at takeoff of 4 percent. 

(b) After a critical loss of thrust on 

multiengine airplanes— 

(1) For levels 1and 2 low-speed 

airplanes that do not meet single engine 

crashworthiness requirements, a 1.5 

percent climb gradient at a pressure 

altitude of 5,000 feet (1,524 meters) in 

the cruise configuration; 

(2) For levels 1 and 2 high-speed 

airplanes, and level 3 low-speed 

airplanes, a 1 percent climb gradient at 

400 feet (122 meters) above the takeoff 

surface with the landing gear retracted 

and flaps in the takeoff configuration; 

(3) For level 3 high-speed airplanes 

and all level 4 airplanes, a 2 percent 

climb gradient at 400 feet (122 meters) 

above the takeoff surface with the 

landing gear retracted and flaps in the 

approach configuration; 

(4) At sea level for level 1 and level 

2 low-speed airplanes; and 

(5) At the landing surface for all other 

airplanes. 

(c) For a balked landing, a climb 

gradient of 3 percent with— 

(1) Takeoff power on each engine; 

(2) Landing gear extended; and 

(3) Flaps in the landing configuration. 

§ 23.125 Climb information. 

(a) The applicant must determine 

climb performance— 

(1) For all single engine airplanes; 

(2) For level 3 multiengine airplanes, 

following a critical loss of thrust on 

takeoff in the initial climb 

configuration; and 

(3) For all multiengine airplanes, 

during the enroute phase of flight with 

all engines operating and after a critical 

loss of thrust in the cruise configuration. 

(b) For single engine airplanes, the 

applicant must determine the glide 

performance of the airplane after a 

complete loss of thrust. 

§ 23.130 Landing. 

The applicant must determine the 

following, for standard temperatures at 

each weight and altitude within the 

operational limits for landing: 

(a) The distance, starting from a 

height of 50 feet (15 meters) above the 

landing surface, required to land and 

come to a stop, or for water operations, 

reach a speed of 3 knots. 

(b) The approach and landing speeds, 

configurations, and procedures, which 

allow a pilot of average skill to meet the 

landing distance consistently and 

without causing damage or injury. 

Flight Characteristics 

§ 23.200 Controllability. 

(a) The airplane must be controllable 

and maneuverable, without requiring 

exceptional piloting skill, alertness, or 

strength, within the operating 

envelope— 

(1) At all loading conditions for which 

certification is requested; 

(2) During low-speed operations, 

including stalls; 

(3) With any probable flight control or 

propulsion system failure; and 

(4) During configuration changes. 

(b) The airplane must be able to 

complete a landing without causing 

damage or serious injury, in the landing 

configuration at a speed of VREF minus 

5 knots using the approach gradient 

equal to the steepest used in the landing 

distance determination. 

(c) For levels 1 and 2 multiengine 

airplanes that cannot climb after a 

critical loss of thrust, VMC must not 

exceed VS1 or VS0 for all practical 

weights and configurations within the 

operating envelope of the airplane. 

(d) If the applicant requests 

certification of an airplane for 

aerobatics, the applicant must 

demonstrate those aerobatic maneuvers 

for which certification is requested and 

determine entry speeds. 

§ 23.205 Trim. 

(a) The airplane must maintain 

longitudinal, lateral, and directional 

trim under the following conditions: 

(1) For levels 1, 2, and 3 airplanes, in 

cruise, without further force upon, or 

movement of, the primary flight controls 

or corresponding trim controls by the 

pilot, or the flight control system. 

(2) For level 4 airplanes in normal 

operations, without further force upon, 

or movement of, the primary flight 

controls or corresponding trim controls 

by the pilot, or the flight control system. 

(b) The airplane must maintain 

longitudinal trim under the following 

conditions: 

(1) Climb. 

(2) Level flight. 

(3) Descent. 

(4) Approach. 

(c) Residual forces must not fatigue or 

distract the pilot during likely 

emergency operations, including a 

critical loss of thrust on multiengine 

airplanes. 

§ 23.210 Stability. 

(a) Airplanes not certified for 

aerobatics must— 

(1) Have static longitudinal, lateral, 

and directional stability in normal 

operations; 

(2) Have dynamic short period and 

combined lateral-directional stability in 

normal operations; and 

(3) Provide stable control force 

feedback throughout the operating 

envelope. 

(b) No airplane may exhibit any 

divergent longitudinal stability 

characteristic so unstable as to increase 

the pilot’s workload or otherwise 

endanger the airplane and its occupants. 

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§ 23.215 Stall characteristics, stall 

warning, and spins. 

(a) The airplane must have 

controllable stall characteristics in 

straight flight, turning flight, and 

accelerated turning flight with a clear 

and distinctive stall warning that 

provides sufficient margin to prevent 

inadvertent stalling. 

(b) Levels 1 and 2 airplanes and level 

3 single-engine airplanes, not certified 

for aerobatics, must not have a tendency 

to inadvertently depart controlled flight. 

(c) Airplanes certified for aerobatics 

must have controllable stall 

characteristics and the ability to recover 

within one and one-half additional 

turns after initiation of the first control 

action from any point in a spin, not 

exceeding six turns or any greater 

number of turns for which certification 

is requested, while remaining within the 

operating limitations of the airplane. 

(d) Spin characteristics in airplanes 

certified for aerobatics must not result 

in unrecoverable spins— 

(1) With any use of the flight or 

engine power controls; or 

(2) Due to pilot disorientation or 

incapacitation. 

§ 23.220 Ground and water handling 

characteristics. 

(a) For airplanes intended for 

operation on land or water, the airplane 

must have controllable longitudinal and 

directional handling characteristics 

during taxi, takeoff, and landing 

operations. 

(b) For airplanes intended for 

operation on water, the following must 

be established and included in the 

Airplane Flight Manual (AFM): 

(1) The maximum wave height at 

which the aircraft demonstrates 

compliance to paragraph (a) of this 

section. This wave height does not 

constitute an operating limitation. 

(2) Any necessary water handling 

procedures. 

§ 23.225 Vibration, buffeting, and highspeed characteristics. 

(a) Vibration and buffeting, for 

operations up to VD/MD, must not 

interfere with the control of the airplane 

or cause fatigue to the flightcrew. Stall 

warning buffet within these limits is 

allowable. 

(b) For high-speed airplanes and all 

airplanes with a maximum operating 

altitude greater than 25,000 feet (7,620 

meters) pressure altitude, there must be 

no perceptible buffeting in cruise 

configuration at 1g and at any speed up 

to VMO/MMO, except stall buffeting. 

(c) For high-speed airplanes, the 

applicant must determine the positive 

maneuvering load factors at which the 

onset of perceptible buffet occurs in the 

cruise configuration within the 

operational envelope. Likely inadvertent 

excursions beyond this boundary must 

not result in structural damage. 

(d) High-speed airplanes must have 

recovery characteristics that do not 

result in structural damage or loss of 

control, beginning at any likely speed 

up to VMO/MMO, following— 

(1) An inadvertent speed increase; 

and 

(2) A high-speed trim upset. 

§ 23.230 Performance and flight 

characteristics requirements for flight in 

icing conditions. 

(a) If an applicant requests 

certification for flight in icing 

conditions as specified in part 1 of 

appendix C to part 25 of this chapter 

and any additional atmospheric icing 

conditions for which an applicant 

requests certification, the applicant 

must demonstrate the following: 

(1) Compliance with each requirement 

of this subpart, except those applicable 

to spins and any that must be 

demonstrated at speeds in excess of— 

(i) 250 knots CAS; 

(ii) VMO or MMO; or 

(iii) A speed at which the applicant 

demonstrates the airframe will be free of 

ice accretion. 

(2) The stall warning for flight in icing 

conditions and non-icing conditions is 

the same. 

(b) If an applicant requests 

certification for flight in icing 

conditions, the applicant must provide 

a means to detect any icing conditions 

for which certification is not requested 

and demonstrate the aircraft’s ability to 

avoid or exit those conditions. 

(c) The applicant must develop an 

operating limitation to prohibit 

intentional flight, including takeoff and 

landing, into icing conditions for which 

the airplane is not certified to operate. 

Subpart C—Structures 

§ 23.300 Structural design envelope. 

The applicant must determine the 

structural design envelope, which 

describes the range and limits of 

airplane design and operational 

parameters for which the applicant will 

show compliance with the requirements 

of this subpart. The applicant must 

account for all airplane design and 

operational parameters that affect 

structural loads, strength, durability, 

and aeroelasticity, including: 

(a) Structural design airspeeds and 

Mach numbers, including— 

(1) The design maneuvering airspeed, 

VA, which may be no less than the 

airspeed at which the airplane will stall 

at the maximum design maneuvering 

load factor; 

(2) The design cruising airspeed, VC

or MC, which may be no less than the 

maximum speed expected in normal 

operations; 

(3) The design dive airspeed, VD or 

MD, which is the airspeed that will not 

be exceeded by inadvertent airspeed 

increases when operating at VC or MC; 

(4) Any other design airspeed 

limitations required for the operation of 

high lift devices, landing gear, and other 

equipment or devices; and 

(5) For level 4 airplanes, a rough air 

penetration speed, VB. 

(b) Design maneuvering load factors 

not less than those, which service 

history shows, may occur within the 

structural design envelope. 

(c) Inertial properties including 

weight, center of gravity, and mass 

moments of inertia, accounting for— 

(1) All weights from the airplane 

empty weight to the maximum weight; 

and 

(2) The weight and distribution of 

occupants, payload, and fuel. 

(d) Range of motion for control 

surfaces, high lift devices, or other 

moveable surfaces, including tolerances. 

(e) All altitudes up to the maximum 

altitude. 

§ 23.305 Interaction of systems and 

structures. 

For airplanes equipped with systems 

that affect structural performance, either 

directly or as a result of failure or 

malfunction, the applicant must account 

for the influence and failure conditions 

of these systems when showing 

compliance with the requirements of 

this subpart. 

Structural Loads 

§ 23.310 Structural design loads. 

The applicant must: 

(a) Determine structural design loads 

resulting from any externally or 

internally applied pressure, force, or 

moment which may occur in flight, 

ground and water operations, ground 

and water handling, and while the 

airplane is parked or moored. 

(b) Determine the loads required by 

paragraph (a) of this section at all 

critical combinations of parameters, on 

and within the boundaries of the 

structural design envelope. 

(c) The magnitude and distribution of 

these loads must be based on physical 

principles and may be no less than 

service history shows will occur within 

the structural design envelope. 

§ 23.315 Flight load conditions. 

The applicant must determine the 

structural design loads resulting from 

the following flight conditions: 

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(a) Vertical and horizontal 

atmospheric gusts where the magnitude 

and gradient of these gusts are based on 

measured gust statistics. 

(b) Symmetric and asymmetric 

maneuvers. 

(c) For canted lifting surfaces, vertical 

and horizontal loads acting 

simultaneously resulting from gust and 

maneuver conditions. 

(d) For multiengine airplanes, failure 

of the powerplant unit which results in 

the most severe structural loads. 

§ 23.320 Ground and water load 

conditions. 

The applicant must determine the 

structural design loads resulting from 

the following ground and water 

operations: 

(a) For airplanes intended for 

operation on land—taxi, takeoff, 

landing, and ground handling 

conditions occurring in normal and 

adverse attitudes and configurations. 

(b) For airplanes intended for 

operation on water—taxi, takeoff, 

landing, and water handling conditions 

occurring in normal and adverse 

attitudes and configurations in the most 

severe sea conditions expected in 

operation. 

(c) Jacking and towing conditions. 

§ 23.325 Component loading conditions. 

The applicant must determine the 

structural design loads acting on: 

(a) Each engine mount and its 

supporting structure resulting from 

engine operation combined with gusts 

and maneuvers. 

(b) Each flight control and high lift 

surface, their associated system and 

supporting structure resulting from— 

(1) The inertia of each surface and 

mass balance attachment; 

(2) Gusts and maneuvers; 

(3) Pilot or automated system inputs; 

(4) System induced conditions, 

including jamming and friction; and 

(5) Ground operations, including 

downwind taxi and ground gusts. 

(c) A pressurized cabin resulting from 

the pressurization differential— 

(1) From zero up to the maximum 

relief valve setting combined with gust 

and maneuver loads; 

(2) From zero up to the maximum 

relief valve setting combined with 

ground and water loads if the airplane 

may land with the cabin pressurized; 

and 

(3) At the maximum relief valve 

setting multiplied by 1.33, omitting all 

other loads. 

§ 23.330 Limit and ultimate loads. 

Unless special or other factors of 

safety are necessary to meet the 

requirements of this subpart, the 

applicant must determine— 

(a) The limit loads, which are equal to 

the structural design loads; and 

(b) The ultimate loads, which are 

equal to the limit loads multiplied by a 

1.5 factor of safety. 

Structural Performance 

§ 23.400 Structural strength. 

The applicant must demonstrate that 

the structure will support: 

(a) Limit loads without— 

(1) Interference with the operation of 

the airplane; and 

(2) Detrimental permanent 

deformation. 

(b) Ultimate loads. 

§ 23.405 Structural durability. 

(a) The applicant must develop and 

implement procedures to prevent 

structural failures due to foreseeable 

causes of strength degradation, which 

could result in serious or fatal injuries, 

loss of the airplane, or extended periods 

of operation with reduced safety 

margins. The Instructions for Continued 

Airworthiness must include procedures 

developed under this section. 

(b) If a pressurized cabin has two or 

more compartments separated by 

bulkheads or a floor, the applicant must 

design the structure for a sudden release 

of pressure in any compartment that has 

a door or window, considering failure of 

the largest door or window opening in 

the compartment. 

(c) For airplanes with maximum 

operating altitude greater than 41,000 

feet, the procedures developed for 

compliance to paragraph (a) of this 

section must be capable of detecting 

damage to the pressurized cabin 

structure before the damage could result 

in rapid decompression that would 

result in serious or fatal injuries. 

(d) The airplane must be capable of 

continued safe flight and landing with 

structural damage caused by highenergy fragments from an uncontained 

engine or rotating machinery failure. 

§ 23.410 Aeroelasticity. 

(a) The airplane must be free from 

flutter, control reversal, and 

divergence— 

(1) At all speeds within and 

sufficiently beyond the structural design 

envelope; 

(2) For any configuration and 

condition of operation; 

(3) Accounting for critical degrees of 

freedom; and 

(4) Accounting for any critical failures 

or malfunctions. 

(b) The applicant must establish and 

account for tolerances for all quantities 

that affect flutter. 

Design 

§ 23.500 Structural design. 

(a) The applicant must design each 

part, article, and assembly for the 

expected operating conditions of the 

airplane. 

(b) Design data must adequately 

define the part, article, or assembly 

configuration, its design features, and 

any materials and processes used. 

(c) The applicant must determine the 

suitability of each design detail and part 

having an important bearing on safety in 

operations. 

(d) The control system must be free 

from jamming, excessive friction, and 

excessive deflection when— 

(1) The control system and its 

supporting structure are subjected to 

loads corresponding to the limit 

airloads; 

(2) The primary controls are subjected 

to the lesser of the limit airloads or limit 

pilot forces; and 

(3) The secondary controls are 

subjected to loads not less than those 

corresponding to maximum pilot effort. 

§ 23.505 Protection of structure. 

(a) The applicant must protect each 

part of the airplane, including small 

parts such as fasteners, against 

deterioration or loss of strength due to 

any cause likely to occur in the 

expected operational environment. 

(b) Each part of the airplane must 

have adequate provisions for ventilation 

and drainage. 

(c) For each part that requires 

maintenance, preventive maintenance, 

or servicing, the applicant must 

incorporate a means into the aircraft 

design to allow such actions to be 

accomplished. 

§ 23.510 Materials and processes. 

(a) The applicant must determine the 

suitability and durability of materials 

used for parts, articles, and assemblies, 

the failure of which could prevent 

continued safe flight and landing. The 

applicant must account for the effects of 

likely environmental conditions 

expected in service. 

(b) The methods and processes of 

fabrication and assembly used must 

produce consistently sound structures. 

If a fabrication process requires close 

control to reach this objective, the 

applicant must perform the process 

under an approved process 

specification. 

(c) Except as provided in paragraphs 

(f) and (g) of this section, the applicant 

must select design values that ensure 

material strength with probabilities that 

account for the criticality of the 

structural element. Design values must 

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account for the probability of structural 

failure due to material variability. 

(d) If material strength properties are 

required, a determination of those 

properties must be based on sufficient 

tests of material meeting specifications 

to establish design values on a statistical 

basis. 

(e) If thermal effects are significant on 

an essential component or structure 

under normal operating conditions, the 

applicant must determine those effects 

on allowable stresses used for design. 

(f) Design values, greater than the 

minimums specified by this section, 

may be used, where only guaranteed 

minimum values are normally allowed, 

if a specimen of each individual item is 

tested before use to determine that the 

actual strength properties of that 

particular item will equal or exceed 

those used in the design. 

(g) An applicant may use other 

material design values if approved by 

the Administrator. 

§ 23.515 Special factors of safety. 

(a) The applicant must determine a 

special factor of safety for any critical 

design value that is— 

(1) Uncertain; 

(2) Used for a part, article, or 

assembly that is likely to deteriorate in 

service before normal replacement; or 

(3) Subject to appreciable variability 

because of uncertainties in 

manufacturing processes or inspection 

methods. 

(b) The applicant must determine a 

special factor of safety using quality 

controls and specifications that account 

for each— 

(1) Structural application; 

(2) Inspection method; 

(3) Structural test requirement; 

(4) Sampling percentage; and 

(5) Process and material control. 

(c) The applicant must apply any 

special factor of safety in the design for 

each part of the structure by multiplying 

each limit load and ultimate load by the 

special factor of safety. 

Structural Occupant Protection 

§ 23.600 Emergency conditions. 

(a) The airplane, even when damaged 

in an emergency landing, must protect 

each occupant against injury that would 

preclude egress when— 

(1) Properly using safety equipment 

and features provided for in the design; 

(2) The occupant experiences ultimate 

static inertia loads likely to occur in an 

emergency landing; and 

(3) Items of mass, including engines 

or auxiliary power units (APUs), within 

or aft of the cabin, that could injure an 

occupant, experience ultimate static 

inertia loads likely to occur in an 

emergency landing. 

(b) The emergency landing conditions 

specified in paragraph (a) of this 

section, must— 

(1) Include dynamic conditions that 

are likely to occur with an impact at 

stall speed, accounting for variations in 

aircraft mass, flight path angle, flight 

pitch angle, yaw, and airplane 

configuration, including likely failure 

conditions at impact; and 

(2) Not exceed established human 

injury criteria for human tolerance due 

to restraint or contact with objects in the 

airplane. 

(c) The airplane must have seating 

and restraints for all occupants. The 

airplane seating, restraints, and cabin 

interior must account for likely flight 

and emergency landing conditions. 

(d) Each occupant restraint system 

must consist of a seat, a method to 

restrain the occupant’s pelvis and torso, 

and a single action restraint release. For 

all flight and ground loads during 

normal operation and any emergency 

landing conditions, the restraint system 

must perform its intended function and 

not create a hazard that could cause a 

secondary injury to an occupant. The 

restraint system must not prevent 

occupant egress or interfere with the 

operation of the airplane when not in 

use. 

(e) Each baggage and cargo 

compartment must— 

(1) Be designed for its maximum 

weight of contents and for the critical 

load distributions at the maximum load 

factors corresponding to the flight and 

ground load conditions determined 

under this part; 

(2) Have a means to prevent the 

contents of the compartment from 

becoming a hazard by impacting 

occupants or shifting; and 

(3) Protect any controls, wiring, lines, 

equipment, or accessories whose 

damage or failure would affect 

operations. 

Subpart D—Design and Construction 

§ 23.700 Flight control systems. 

(a) The applicant must design 

airplane flight control systems to: 

(1) Prevent major, hazardous, and 

catastrophic hazards, including— 

(i) Failure; 

(ii) Operational hazards; 

(iii) Flutter; 

(iv) Asymmetry; and 

(v) Misconfiguration. 

(2) Operate easily, smoothly, and 

positively enough to allow normal 

operation. 

(b) The applicant must design trim 

systems to: 

(1) Prevent inadvertent, incorrect, or 

abrupt trim operation. 

(2) Provide a means to indicate— 

(i) The direction of trim control 

movement relative to airplane motion; 

(ii) The trim position with respect to 

the trim range; 

(iii) The neutral position for lateral 

and directional trim; and 

(iv) For all airplanes, except simple 

airplanes, the range for takeoff for all 

applicant requested center of gravity 

ranges and configurations. 

(3) Except for simple airplanes, 

provide control for continued safe flight 

and landing when any one connecting 

or transmitting element in the primary 

flight control system fails. 

(4) Limit the range of travel to allow 

safe flight and landing, if an adjustable 

stabilizer is used. 

(c) For an airplane equipped with an 

artificial stall barrier system, the system 

must— 

(1) Prevent uncommanded control or 

thrust action; and 

(2) Provide for a preflight check. 

(d) For level 3 high-speed and all 

level 4 airplanes, an applicant must 

install a takeoff warning system on the 

airplane unless the applicant 

demonstrates the airplane, for each 

configuration, can takeoff at the limits of 

the trim and flap ranges. 

§ 23.705 Landing gear systems. 

(a) For airplanes with retractable 

landing gear: 

(1) The landing gear and retracting 

mechanism, including the wheel well 

doors, must be able to withstand 

operational and flight loads. 

(2) The airplane must have— 

(i) A positive means to keep the 

landing gear extended; 

(ii) A secondary means of extension 

for landing gear that cannot be extended 

using the primary means; 

(iii) A means to inform the pilot that 

each landing gear is secured in the 

extended and retracted positions; and 

(iv) Except for airplanes intended for 

operation on water, a warning to the 

pilot if the thrust and configuration is 

selected for landing and the landing 

gear is not fully extended and locked. 

(3) If the landing gear bay is used as 

the location for equipment other than 

the landing gear, that equipment must 

be designed and installed to avoid 

damage from tire burst and from items 

that may enter the landing gear bay. 

(b) The design of each landing gear 

wheel, tire, and ski must account for 

critical loads, including those 

experienced during landing and rejected 

takeoff. 

(c) A reliable means of stopping the 

airplane must provide kinetic energy 

absorption within the airplane’s design 

specifications for landing. 

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(d) For levels 3 and 4 multiengine 

airplanes, the braking system must 

provide kinetic energy absorption 

within the airplane’s design 

specifications for rejected takeoff. 

§ 23.710 Buoyancy for seaplanes and 

amphibians. 

Airplanes intended for operations on 

water, must— 

(a) Provide buoyancy of 80 percent in 

excess of the buoyancy required to 

support the maximum weight of the 

airplane in fresh water; and 

(b) Have sufficient watertight 

compartments so the airplane will stay 

afloat at rest in calm water without 

capsizing if any two compartments of 

any main float or hull are flooded. 

Occupant System Design Protection 

§ 23.750 Means of egress and emergency 

exits. 

(a) The airplane cabin exit design 

must provide for evacuation of the 

airplane within 90 seconds in 

conditions likely to occur following an 

emergency landing. Likely conditions 

exclude ditching for all but levels 3 and 

4 multiengine airplanes. 

(b) Each exit must have a means to be 

opened from both inside and outside the 

airplane, when the internal locking 

mechanism is in the locked and 

unlocked position. The means of 

opening must be simple, obvious, and 

marked inside and outside the airplane. 

(c) Airplane evacuation paths must 

protect occupants from serious injury 

from the propulsion system. 

(d) Each exit must not be obstructed 

by a seat or seat back, unless the seat or 

seat back can be easily moved in one 

action to clear the exit. 

(e) Airplanes certified for aerobatics 

must have a means to egress the 

airplane in flight. 

(f) Doors, canopies, and exits must be 

protected from opening inadvertently in 

flight. 

§ 23.755 Occupant physical environment. 

(a) The applicant must design the 

airplane to— 

(1) Allow clear communication 

between the flightcrew and passengers; 

(2) Provide a clear, sufficiently 

undistorted external view to enable the 

flightcrew to perform any maneuvers 

within the operating limitations of the 

airplane; 

(3) Protect the pilot from serious 

injury due to high energy rotating 

failures in systems and equipment; and 

(4) Protect the occupants from serious 

injury due to damage to windshields, 

windows, and canopies. 

(b) For level 4 airplanes, each 

windshield and its supporting structure 

directly in front of the pilot must— 

(1) Withstand, without penetration, 

the impact equivalent to a two-pound 

bird when the velocity of the airplane is 

equal to the airplane’s maximum 

approach flap speed; and 

(2) Allow for continued safe flight and 

landing after the loss of vision through 

any one panel. 

(c) The airplane must provide each 

occupant with air at a breathable 

pressure, free of hazardous 

concentrations of gases and vapors, 

during normal operations and likely 

failures. 

(d) If an oxygen system is installed in 

the airplane, it must include— 

(1) A means to allow the flightcrew to 

determine the quantity of oxygen 

available in each source of supply on 

the ground and in flight; 

(2) A means to determine whether 

oxygen is being delivered; and 

(3) A means to permit the flightcrew 

to turn on and shut off the oxygen 

supply at any high-pressure source in 

flight. 

(e) If a pressurization system is 

installed in the airplane, it must 

include— 

(1) A warning if an unsafe condition 

exists; and 

(2) A pressurization system test. 

Fire and High Energy Protection 

§ 23.800 Fire protection outside 

designated fire zones. 

Outside designated fire zones: 

(a) The following materials must be 

self-extinguishing— 

(1) Insulation on electrical wire and 

electrical cable; 

(2) For levels 1, 2, and 3 airplanes, 

materials in the baggage and cargo 

compartments inaccessible in flight; and 

(3) For level 4 airplanes, materials in 

the cockpit, cabin, baggage, and cargo 

compartments. 

(b) The following materials must be 

flame resistant— 

(1) For levels 1, 2 and 3 airplanes, 

materials in each compartment 

accessible in flight; and 

(2) Any electrical cable installation 

that would overheat in the event of 

circuit overload or fault. 

(c) Thermal acoustic materials, if 

installed, must not be a flame 

propagation hazard. 

(d) Sources of heat that are capable of 

igniting adjacent objects must be 

shielded and insulated to prevent such 

ignition. 

(e) For level 4 airplanes, each baggage 

and cargo compartment must— 

(1) Be located where a fire would be 

visible to the pilots, or equipped with a 

fire detection system and warning 

system; and 

(2) Be accessible for the manual 

extinguishing of a fire, have a built-in 

fire extinguishing system, or be 

constructed and sealed to contain any 

fire within the compartment. 

(f) There must be a means to 

extinguish any fire in the cabin such 

that— 

(1) The pilot, while seated, can easily 

access the fire extinguishing means; and 

(2) For levels 3 and 4 airplanes, 

passengers have a fire extinguishing 

means available within the passenger 

compartment. 

(g) Each area where flammable fluids 

or vapors might escape by leakage of a 

fluid system must— 

(1) Be defined; and 

(2) Have a means to make fluid and 

vapor ignition, and the resultant hazard, 

if ignition occurs, improbable. 

(h) Combustion heater installations 

must be protected from uncontained 

fire. 

§ 23.805 Fire protection in designated fire 

zones. 

Inside designated fire zones: 

(a) Flight controls, engine mounts, 

and other flight structures within or 

adjacent to those zones must be capable 

of withstanding the effects of a fire. 

(b) Engines must remain attached to 

the airplane in the event of a fire or 

electrical arcing. 

(c) Terminals, equipment, and 

electrical cables used during emergency 

procedures must be fire-resistant. 

§ 23.810 Lightning protection of structure. 

(a) For airplanes approved for 

instrument flight rules, no structural 

failure preventing continued safe flight 

and landing may occur from exposure to 

the direct effects of lightning. 

(b) Airplanes approved only for visual 

flight rules must achieve lightning 

protection by following FAA accepted 

design practices. 

Subpart E—Powerplant 

§ 23.900 Powerplant installation. 

(a) For the purpose of this subpart, the 

airplane powerplant installation must 

include each component necessary for 

propulsion, affects propulsion safety, or 

provides auxiliary power to the 

airplane. 

(b) The applicant must construct and 

arrange each powerplant installation to 

account for likely hazards in operation 

and maintenance. 

(c) Except for simple airplanes, each 

aircraft power unit must be type 

certificated. 

§ 23.905 Propeller installation. 

(a) Except for simple airplanes, each 

propeller must be type certificated. 

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(b) Each pusher propeller must be 

marked so that it is conspicuous under 

daylight conditions. 

(c) Each propeller installation must 

account for vibration and fatigue. 

§ 23.910 Powerplant installation hazard 

assessment. 

The applicant must assess each 

powerplant separately and in relation to 

other airplane systems and installations 

to show that a failure of any powerplant 

system component or accessory will 

not— 

(a) Prevent continued safe flight and 

landing; 

(b) Cause serious injury that may be 

avoided; and 

(c) Require immediate action by 

crewmembers for continued operation 

of any remaining powerplant system. 

§ 23.915 Automatic power control 

systems. 

A power or thrust augmentation 

system that automatically controls the 

power or thrust on the operating 

powerplant, must— 

(a) Provide indication to the 

flightcrew when the system is operating; 

(b) Provide a means for the pilot to 

deactivate the automatic function; and 

(c) Prevent inadvertent deactivation. 

§ 23.920 Reversing systems. 

The airplane must be capable of 

continued safe flight and landing under 

any available reversing system setting. 

§ 23.925 Powerplant operational 

characteristics. 

(a) The powerplant must operate at 

any negative acceleration that may 

occur during normal and emergency 

operation, within the airplane operating 

limitations. 

(b) The pilot must have the capability 

to stop and restart the powerplant in 

flight. 

(c) The airplane must have an 

independent power source for restarting 

each powerplant following an in-flight 

shutdown. 

§ 23.930 Fuel system 

(a) Each fuel system must— 

(1) Provide an independent fuel 

supply to each powerplant in at least 

one configuration; 

(2) Avoid ignition from unplanned 

sources; 

(3) Provide the fuel required to 

achieve maximum power or thrust plus 

a margin for likely variables, in all 

temperature and altitude conditions 

within the airplane operating envelope; 

(4) Provide a means to remove the fuel 

from the airplane; 

(5) Be capable of retaining fuel when 

subject to inertia loads under expected 

operating conditions; and 

(6) Prevent hazardous contamination 

of the fuel supply. 

(b) Each fuel storage system must— 

(1) Withstand the loads and pressures 

under expected operating conditions; 

(2) Provide a means to prevent loss of 

fuel during any maneuver under 

operating conditions for which 

certification is requested; 

(3) Prevent discharge when 

transferring fuel; 

(4) Provide fuel for at least one-half 

hour of operation at maximum 

continuous power or thrust; and 

(5) Be capable of jettisoning fuel if 

required for landing. 

(c) If a pressure refueling system is 

installed, it must have a means to— 

(1) Prevent the escape of hazardous 

quantities of fuel; 

(2) Automatically shut-off before 

exceeding the maximum fuel quantity of 

the airplane; and 

(3) Provide an indication of a failure 

at the fueling station. 

§ 23.935 Powerplant induction and 

exhaust systems. 

The air induction system for each 

power unit and its accessories must— 

(a) Supply the air required by that 

power unit and its accessories under 

expected operating conditions; and 

(b) Provide a means to discharge 

potential harmful material. 

§ 23.940 Powerplant ice protection. 

(a) The airplane design must prevent 

foreseeable accumulation of ice or snow 

that adversely affects powerplant 

operation. 

(b) The powerplant design must 

prevent any accumulation of ice or 

snow that adversely affects powerplant 

operation, in those icing conditions for 

which certification is requested. 

§ 23.1000 Powerplant fire protection. 

(a) A powerplant may only be 

installed in a designated fire zone. 

(b) Each component, line, and fitting 

carrying flammable fluids, gases, or air 

subject to fire conditions must be fire 

resistant, except components storing 

concentrated flammable material must 

be fireproof or enclosed by a fireproof 

shield. 

(c) The applicant must provide a 

means to shut off fuel or flammable 

material for each powerplant that 

must— 

(1) Not restrict fuel to remaining 

units; and 

(2) Prevent inadvertent operation. 

(d) For levels 3 and 4 airplanes with 

a powerplant located outside the pilot’s 

view that uses combustible fuel, the 

applicant must install a fire 

extinguishing system. 

(e) For levels 3 and 4 airplanes, the 

applicant must install a fire detection 

system in each designated fire zone. 

(f) Each fire detection system must 

provide a means to alert the flightcrew 

in the event of a detection of fire or 

failure of the system. 

(g) There must be a means to check 

the fire detection system in flight. 

Subpart F—Equipment 

§ 23.1300 Airplane level systems 

requirements. 

(a) The equipment and systems 

required for an airplane to operate safely 

in the kinds of operations for which 

certification is requested (Day VFR, 

Night VFR, IFR) must be designed and 

installed to— 

(1) Meet the level of safety applicable 

to the certification and performance 

level of the airplane; and 

(2) Perform their intended function 

throughout the operating and 

environmental limits specified by the 

applicant. 

(b) Non-required airplane equipment 

and systems, considered separately and 

in relation to other systems, must be 

designed and installed so their 

operation or failure does not have an 

adverse effect on the airplane or its 

occupants. 

§ 23.1305 Function and installation. 

(a) Each item of installed equipment 

must— 

(1) Perform its intended function; 

(2) Be installed according to 

limitations specified for that equipment; 

and 

(3) Be labeled, if applicable, as to its 

identification, function or operating 

limitations, or any combination of these 

factors. 

(b) There must be a discernable means 

of providing system operating 

parameters required to operate the 

airplane, including warnings, cautions, 

and normal indications to the 

responsible crewmember. 

(c) Information concerning an unsafe 

system operating condition must be 

provided in a timely manner to the 

crewmember responsible for taking 

corrective action. Presentation of this 

information must be clear enough to 

avoid likely crewmember errors. 

§ 23.1310 Flight, navigation, and 

powerplant instruments. 

(a) Installed systems must provide the 

flightcrew member who sets or monitors 

flight parameters for the flight, 

navigation, and powerplant the 

information necessary to do so during 

each phase of flight. This information 

must include— 

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(1) Parameters and trends, as needed 

for normal, abnormal, and emergency 

operation; and 

(2) Limitations, unless the applicant 

shows each limitation will not be 

exceeded in all intended operations. 

(b) Indication systems that integrate 

the display of flight or powerplant 

parameters to operate the airplane or are 

required by the operating rules of this 

chapter must— 

(1) Not inhibit the primary display of 

flight or powerplant parameters needed 

by any flightcrew member in any 

normal mode of operation; and 

(2) In combination with other 

systems, be designed and installed so 

information essential for continued safe 

flight and landing will be available to 

the flightcrew in a timely manner after 

any single failure or probable 

combination of failures. 

§ 23.1315 Equipment, systems, and 

installations. 

For any airplane system or equipment 

whose failure or abnormal operation has 

not been specifically addressed by 

another requirement in this part, the 

applicant must: 

(a) Examine the design and 

installation of airplane systems and 

equipment, separately and in relation to 

other airplane systems and equipment 

to determine— 

(1) If a failure would prevent 

continued safe flight and landing; and 

(2) If any other failure would 

significantly reduce the capability of the 

airplane or the ability of the flightcrew 

to cope with adverse operating 

conditions. 

(b) Design and install each system and 

equipment, examined separately and in 

relation to other airplane systems and 

equipment, such that— 

(1) Each catastrophic failure condition 

is extremely improbable; 

(2) Each hazardous failure condition 

is extremely remote; and 

(3) Each major failure condition is 

remote. 

§ 23.1320 Electrical and electronic system 

lightning protection. 

For an airplane approved for IFR 

operations: 

(a) Each electrical or electronic system 

that performs a function, the failure of 

which would prevent the continued safe 

flight and landing of the airplane, must 

be designed and installed such that— 

(1) The airplane system level function 

continues to perform during and after 

the time the airplane is exposed to 

lightning; and 

(2) The system automatically recovers 

normal operation of that function in a 

timely manner after the airplane is 

exposed to lightning unless the system’s 

recovery conflicts with other 

operational or functional requirements 

of the system. 

(b) Each electrical and electronic 

system that performs a function, the 

failure of which would reduce the 

capability of the airplane or the ability 

of the flightcrew to respond to an 

adverse operating condition, must be 

designed and installed such that the 

function recovers normal operation in a 

timely manner after the airplane is 

exposed to lightning. 

§ 23.1325 High-intensity Radiated Fields 

(HIRF) protection. 

(a) Electrical and electronic systems 

that perform a function, the failure of 

which would prevent the continued safe 

flight and landing of the airplane, must 

be designed and installed such that— 

(1) The airplane system level function 

is not adversely affected during and 

after the time the airplane is exposed to 

the HIRF environment; and 

(2) The system automatically recovers 

normal operation of that function in a 

timely manner after the airplane is 

exposed to the HIRF environment, 

unless the system’s recovery conflicts 

with other operational or functional 

requirements of the system. 

(b) For airplanes approved for IFR 

operations, the applicant must design 

and install each electrical and electronic 

system that performs a function, the 

failure of which would reduce the 

capability of the airplane or the ability 

of the flightcrew to respond to an 

adverse operating condition, so the 

function recovers normal operation in a 

timely manner after the airplane is 

exposed to the HIRF environment. 

§ 23.1330 System power generation, 

storage, and distribution. 

The power generation, storage, and 

distribution for any system must be 

designed and installed to— 

(a) Supply the power required for 

operation of connected loads during all 

likely operating conditions; 

(b) Ensure no single failure or 

malfunction will prevent the system 

from supplying the essential loads 

required for continued safe flight and 

landing; and 

(c) Have enough capacity, if the 

primary source fails, to supply essential 

loads, including non-continuous 

essential loads for the time needed to 

complete the function, for— 

(1) At least 30 minutes for airplanes 

certificated with a maximum altitude of 

25,000 feet (7,620 meters) or less; and 

(2) At least 60 minutes for airplanes 

certificated with a maximum altitude 

over 25,000 feet (7,620 meters). 

§ 23.1335 External and cockpit lighting. 

(a) The applicant must design and 

install all lights to prevent adverse 

effects on the performance of flightcrew 

duties. 

(b) Any position and anti-collision 

lights, if required by part 91 of this 

chapter, must have the intensities, flash 

rate, colors, fields of coverage, and other 

characteristics to provide sufficient time 

for another aircraft to avoid a collision. 

(c) Any position lights, if required by 

part 91 of this chapter, must include a 

red light on the left side of the airplane, 

a green light on the right side of the 

airplane, spaced laterally as far apart as 

space allows, and a white light facing 

aft, located on an aft portion of the 

airplane or on the wing tips. 

(d) The applicant must design and 

install taxi and landing lights so they 

provide sufficient light for night 

operations. 

(e) For seaplanes or amphibian 

airplanes, riding lights must provide a 

white light visible in clear atmospheric 

conditions. 

§ 23.1400 Safety equipment. 

Safety and survival equipment, 

required by the operating rules of this 

chapter, must be reliable, readily 

accessible, easily identifiable, and 

clearly marked to identify its method of 

operation. 

§ 23.1405 Flight in icing conditions. 

(a) If an applicant requests 

certification for flight in icing 

conditions, the applicant must 

demonstrate that— 

(1) The ice protection system provides 

for safe operation; and 

(2) The airplane is protected from 

stalling when the autopilot is operating 

in a vertical mode. 

(b) The demonstration specified in 

paragraph (a) of this section, must be 

conducted in atmospheric icing 

conditions specified in part 1 of 

appendix C to part 25 of this chapter, 

and any additional icing conditions for 

which certification is requested. 

§ 23.1410 Pressurized systems elements. 

(a) The minimum burst pressure of 

hydraulic systems must be at least 2.5 

times the design operating pressure. The 

proof pressure must be at least 1.5 times 

the maximum operating pressure. 

(b) On multiengine airplanes, engine 

driven accessories essential to safe 

operation must be distributed among 

multiple engines. 

(c) The minimum burst pressure of 

cabin pressurization system elements 

must be at least 2.0 times, and proof 

pressure must be at least 1.5 times, the 

maximum normal operating pressure. 

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(d) The minimum burst pressure of 

pneumatic system elements must be at 

least 3.0 times, and proof pressure must 

be at least 1.5 times, the maximum 

normal operating pressure. 

(e) Other pressurized system elements 

must have pressure margins that take 

into account system design and 

operating conditions. 

§ 23.1457 Cockpit voice recorders. 

(a) Each cockpit voice recorder 

required by the operating rules of this 

chapter must be approved and must be 

installed so that it will record the 

following: 

(1) Voice communications transmitted 

from or received in the airplane by 

radio. 

(2) Voice communications of 

flightcrew members on the flight deck. 

(3) Voice communications of 

flightcrew members on the flight deck, 

using the airplane’s interphone system. 

(4) Voice or audio signals identifying 

navigation or approach aids introduced 

into a headset or speaker. 

(5) Voice communications of 

flightcrew members using the passenger 

loudspeaker system, if there is such a 

system and if the fourth channel is 

available in accordance with the 

requirements of paragraph (c)(4)(ii) of 

this section. 

(6) If datalink communication 

equipment is installed, all datalink 

communications, using an approved 

data message set. Datalink messages 

must be recorded as the output signal 

from the communications unit that 

translates the signal into usable data. 

(b) The recording requirements of 

paragraph (a)(2) of this section must be 

met by installing a cockpit-mounted 

area microphone, located in the best 

position for recording voice 

communications originating at the first 

and second pilot stations and voice 

communications of other crewmembers 

on the flight deck when directed to 

those stations. The microphone must be 

so located and, if necessary, the 

preamplifiers and filters of the recorder 

must be so adjusted or supplemented, so 

that the intelligibility of the recorded 

communications is as high as 

practicable when recorded under flight 

cockpit noise conditions and played 

back. Repeated aural or visual playback 

of the record may be used in evaluating 

intelligibility. 

(c) Each cockpit voice recorder must 

be installed so that the part of the 

communication or audio signals 

specified in paragraph (a) of this section 

obtained from each of the following 

sources is recorded on a separate 

channel: 

(1) For the first channel, from each 

boom, mask, or handheld microphone, 

headset, or speaker used at the first pilot 

station. 

(2) For the second channel from each 

boom, mask, or handheld microphone, 

headset, or speaker used at the second 

pilot station. 

(3) For the third channel—from the 

cockpit-mounted area microphone. 

(4) For the fourth channel from: 

(i) Each boom, mask, or handheld 

microphone, headset, or speaker used at 

the station for the third and fourth 

crewmembers. 

(ii) If the stations specified in 

paragraph (c)(4)(i) of this section are not 

required or if the signal at such a station 

is picked up by another channel, each 

microphone on the flight deck that is 

used with the passenger loudspeaker 

system, if its signals are not picked up 

by another channel. 

(5) And that as far as is practicable all 

sounds received by the microphone 

listed in paragraphs (c)(1), (2), and (4) of 

this section must be recorded without 

interruption irrespective of the position 

of the interphone-transmitter key 

switch. The design shall ensure that 

sidetone for the flightcrew is produced 

only when the interphone, public 

address system, or radio transmitters are 

in use. 

(d) Each cockpit voice recorder must 

be installed so that: 

(1) (i) It receives its electrical power 

from the bus that provides the 

maximum reliability for operation of the 

cockpit voice recorder without 

jeopardizing service to essential or 

emergency loads. 

(ii) It remains powered for as long as 

possible without jeopardizing 

emergency operation of the airplane. 

(2) There is an automatic means to 

simultaneously stop the recorder and 

prevent each erasure feature from 

functioning, within 10 minutes after 

crash impact. 

(3) There is an aural or visual means 

for preflight checking of the recorder for 

proper operation. 

(4) Any single electrical failure 

external to the recorder does not disable 

both the cockpit voice recorder and the 

flight data recorder. 

(5) It has an independent power 

source— 

(i) That provides 10±1 minutes of 

electrical power to operate both the 

cockpit voice recorder and cockpitmounted area microphone; 

(ii) That is located as close as 

practicable to the cockpit voice 

recorder; and 

(iii) To which the cockpit voice 

recorder and cockpit-mounted area 

microphone are switched automatically 

in the event that all other power to the 

cockpit voice recorder is interrupted 

either by normal shutdown or by any 

other loss of power to the electrical 

power bus. 

(6) It is in a separate container from 

the flight data recorder when both are 

required. If used to comply with only 

the cockpit voice recorder requirements, 

a combination unit may be installed. 

(e) The recorder container must be 

located and mounted to minimize the 

probability of rupture of the container as 

a result of crash impact and consequent 

heat damage to the recorder from fire. 

(1) Except as provided in paragraph 

(e)(2) of this section, the recorder 

container must be located as far aft as 

practicable, but need not be outside of 

the pressurized compartment, and may 

not be located where aft-mounted 

engines may crush the container during 

impact. 

(2) If two separate combination digital 

flight data recorder and cockpit voice 

recorder units are installed instead of 

one cockpit voice recorder and one 

digital flight data recorder, the 

combination unit that is installed to 

comply with the cockpit voice recorder 

requirements may be located near the 

cockpit. 

(f) If the cockpit voice recorder has a 

bulk erasure device, the installation 

must be designed to minimize the 

probability of inadvertent operation and 

actuation of the device during crash 

impact. 

(g) Each recorder container must— 

(1) Be either bright orange or bright 

yellow; 

(2) Have reflective tape affixed to its 

external surface to facilitate its location 

under water; and 

(3) Have an underwater locating 

device, when required by the operating 

rules of this chapter, on or adjacent to 

the container, which is secured in such 

manner that they are not likely to be 

separated during crash impact. 

§ 23.1459 Flight data recorders. 

(a) Each flight recorder required by 

the operating rules of this chapter must 

be installed so that— 

(1) It is supplied with airspeed, 

altitude, and directional data obtained 

from sources that meet the aircraft level 

system requirements of § 23.1300 and 

the functionality specified in § 23.1305; 

(2) The vertical acceleration sensor is 

rigidly attached, and located 

longitudinally either within the 

approved center of gravity limits of the 

airplane, or at a distance forward or aft 

of these limits that does not exceed 25 

percent of the airplane’s mean 

aerodynamic chord; 

(3)(i) It receives its electrical power 

from the bus that provides the 

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maximum reliability for operation of the 

flight data recorder without jeopardizing 

service to essential or emergency loads; 

(ii) It remains powered for as long as 

possible without jeopardizing 

emergency operation of the airplane; 

(4) There is an aural or visual means 

for preflight checking of the recorder for 

proper recording of data in the storage 

medium; 

(5) Except for recorders powered 

solely by the engine-driven electrical 

generator system, there is an automatic 

means to simultaneously stop a recorder 

that has a data erasure feature and 

prevent each erasure feature from 

functioning, within 10 minutes after 

crash impact; 

(6) Any single electrical failure 

external to the recorder does not disable 

both the cockpit voice recorder and the 

flight data recorder; and 

(7) It is in a separate container from 

the cockpit voice recorder when both 

are required. If used to comply with 

only the flight data recorder 

requirements, a combination unit may 

be installed. If a combination unit is 

installed as a cockpit voice recorder to 

comply with § 23.1457(e)(2), a 

combination unit must be used to 

comply with this flight data recorder 

requirement. 

(b) Each non-ejectable record 

container must be located and mounted 

so as to minimize the probability of 

container rupture resulting from crash 

impact and subsequent damage to the 

record from fire. In meeting this 

requirement, the record container must 

be located as far aft as practicable, but 

need not be aft of the pressurized 

compartment, and may not be where aftmounted engines may crush the 

container upon impact. 

(c) A correlation must be established 

between the flight recorder readings of 

airspeed, altitude, and heading and the 

corresponding readings (taking into 

account correction factors) of the first 

pilot’s instruments. The correlation 

must cover the airspeed range over 

which the airplane is to be operated, the 

range of altitude to which the airplane 

is limited, and 360 degrees of heading. 

Correlation may be established on the 

ground as appropriate. 

(d) Each recorder container must— 

(1) Be either bright orange or bright 

yellow; 

(2) Have reflective tape affixed to its 

external surface to facilitate its location 

under water; and 

(3) Have an underwater locating 

device, when required by the operating 

rules of this chapter, on or adjacent to 

the container, which is secured in such 

a manner that they are not likely to be 

separated during crash impact. 

(e) Any novel or unique design or 

operational characteristics of the aircraft 

shall be evaluated to determine if any 

dedicated parameters must be recorded 

on flight recorders in addition to or in 

place of existing requirements. 

Subpart G—Flightcrew Interface and 

Other Information 

§ 23.1500 Flightcrew interface. 

(a) The pilot compartment and its 

equipment must allow each pilot to 

perform his or her duties, including 

taxi, takeoff, climb, cruise, descent, 

approach, landing, and perform any 

maneuvers within the operating 

envelope of the airplane, without 

excessive concentration, skill, alertness, 

or fatigue. 

(b) The applicant must install flight, 

navigation, surveillance, and 

powerplant controls and displays so 

qualified flightcrew can monitor and 

perform all tasks associated with the 

intended functions of systems and 

equipment. The system and equipment 

design must make the possibility that a 

flightcrew error could result in a 

catastrophic event highly unlikely. 

§ 23.1505 Instrument markings, control 

markings, and placards. 

(a) Each airplane must display in a 

conspicuous manner any placard and 

instrument marking necessary for 

operation. 

(b) The applicant must clearly mark 

each cockpit control, other than primary 

flight controls, as to its function and 

method of operation. 

(c) The applicant must include 

instrument marking and placard 

information in the Airplane Flight 

Manual. 

§ 23.1510 Airplane flight manual. 

The applicant must provide an 

Airplane Flight Manual that must be 

delivered with each airplane that 

contains the following information— 

(a) Operating limitations and 

procedures; 

(b) Performance information; 

(c) Loading information; and 

(d) Any other information necessary 

for the operation of the airplane. 

§ 23.1515 Instructions for continued 

airworthiness. 

The applicant must prepare 

Instructions for Continued 

Airworthiness, in accordance with 

appendix A of this part, that are 

acceptable to the Administrator prior to 

the delivery of the first airplane or 

issuance of a standard certification of 

airworthiness, whichever occurs later. 

Appendix A to Part 23—Instructions for 

Continued Airworthiness 

A23.1 General 

(a) This appendix specifies 

requirements for the preparation of 

Instructions for Continued 

Airworthiness as required by this part. 

(b) The Instructions for Continued 

Airworthiness for each airplane must 

include the Instructions for Continued 

Airworthiness for each engine and 

propeller (hereinafter designated 

‘‘products’’), for each appliance required 

by this chapter, and any required 

information relating to the interface of 

those appliances and products with the 

airplane. If Instructions for Continued 

Airworthiness are not supplied by the 

manufacturer of an appliance or product 

installed in the airplane, the 

Instructions for Continued 

Airworthiness for the airplane must 

include the information essential to the 

continued airworthiness of the airplane. 

(c) The applicant must submit to the 

FAA a program to show how changes to 

the Instructions for Continued 

Airworthiness made by the applicant or 

by the manufacturers of products and 

appliances installed in the airplane will 

be distributed. 

A23.2 Format 

(a) The Instructions for Continued 

Airworthiness must be in the form of a 

manual or manuals as appropriate for 

the quantity of data to be provided. 

(b) The format of the manual or 

manuals must provide for a practical 

arrangement. 

A23.3 Content 

The contents of the manual or 

manuals must be prepared in the 

English language. The Instructions for 

Continued Airworthiness must contain 

the following manuals or sections and 

information: 

(a) Airplane maintenance manual or 

section. 

(1) Introduction information that 

includes an explanation of the 

airplane’s features and data to the extent 

necessary for maintenance or preventive 

maintenance. 

(2) A description of the airplane and 

its systems and installations including 

its engines, propellers, and appliances. 

(3) Basic control and operation 

information describing how the airplane 

components and systems are controlled 

and how they operate, including any 

special procedures and limitations that 

apply. 

(4) Servicing information that covers 

details regarding servicing points, 

capacities of tanks, reservoirs, types of 

fluids to be used, pressures applicable 

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to the various systems, location of 

access panels for inspection and 

servicing, locations of lubrication 

points, lubricants to be used, equipment 

required for servicing, tow instructions 

and limitations, mooring, jacking, and 

leveling information. 

(b) Maintenance Instructions 

(1) Scheduling information for each 

part of the airplane and its engines, 

auxiliary power units, propellers, 

accessories, instruments, and equipment 

that provides the recommended periods 

at which they should be cleaned, 

inspected, adjusted, tested, and 

lubricated, and the degree of inspection, 

the applicable wear tolerances, and 

work recommended at these periods. 

However, the applicant may refer to an 

accessory, instrument, or equipment 

manufacturer as the source of this 

information if the applicant shows that 

the item has an exceptionally high 

degree of complexity requiring 

specialized maintenance techniques, 

test equipment, or expertise. The 

recommended overhaul periods and 

necessary cross reference to the 

Airworthiness Limitations section of the 

manual must also be included. In 

addition, the applicant must include an 

inspection program that includes the 

frequency and extent of the inspections 

necessary to provide for the continued 

airworthiness of the airplane. 

(2) Troubleshooting information 

describing probable malfunctions, how 

to recognize those malfunctions, and the 

remedial action for those malfunctions. 

(3) Information describing the order 

and method of removing and replacing 

products and parts with any necessary 

precautions to be taken. 

(4) Other general procedural 

instructions including procedures for 

system testing during ground running, 

symmetry checks, weighing and 

determining the center of gravity, lifting 

and shoring, and storage limitations. 

(c) Diagrams of structural access 

plates and information needed to gain 

access for inspections when access 

plates are not provided. 

(d) Details for the application of 

special inspection techniques including 

radiographic and ultrasonic testing 

where such processes are specified by 

the applicant. 

(e) Information needed to apply 

protective treatments to the structure 

after inspection. 

(f) All data relative to structural 

fasteners such as identification, discard 

recommendations, and torque values. 

(g) A list of special tools needed. 

(h) In addition, for level 4 airplanes, 

the following information must be 

furnished— 

(1) Electrical loads applicable to the 

various systems; 

(2) Methods of balancing control 

surfaces; 

(3) Identification of primary and 

secondary structures; and 

(4) Special repair methods applicable 

to the airplane. 

A23.4 Airworthiness limitations 

section 

The Instructions for Continued 

Airworthiness must contain a section 

titled Airworthiness Limitations that is 

segregated and clearly distinguishable 

from the rest of the document. This 

section must set forth each mandatory 

replacement time, structural inspection 

interval, and related structural 

inspection procedure required for type 

certification. If the Instructions for 

Continued Airworthiness consist of 

multiple documents, the section 

required by this paragraph must be 

included in the principal manual. This 

section must contain a legible statement 

in a prominent location that reads ‘‘The 

Airworthiness Limitations section is 

FAA approved and specifies 

maintenance required under §§ 43.16 

and 91.403 of Title 14 of the Code of 

Federal Regulations unless an 

alternative program has been FAA 

approved.’’ 

PART 35—AIRWORTHINESS 

STANDARDS: PROPELLERS 

■ 9. The authority citation for part 35 is 

revised to read as follows: 

Authority: 49 U.S.C. 106(f), 106(g), 40113, 

44701–44702, 44704. 

■ 10. In § 35.1, revise paragraph (c) to 

read as follows: 

§ 35.1 Applicability. 

* * * * * 

(c) An applicant is eligible for a 

propeller type certificate and changes to 

those certificates after demonstrating 

compliance with subparts A, B, and C 

of this part. However, the propeller may 

not be installed on an airplane unless 

the applicant has shown compliance 

with either § 23.905(c) or § 25.907 of 

this chapter, as applicable, or 

compliance is not required for 

installation on that airplane. 

* * * * * 

■ 11. In § 35.37, revise paragraph (c)(1) 

to read as follows: 

§ 35.37 Fatigue limits and evaluation. 

* * * * * 

(c) * * * 

(1) The intended airplane by 

complying with § 23.905(c) or § 25.907 

of this chapter, as applicable; or 

* * * * * 

PART 43—MAINTENANCE, 

PREVENTIVE MAINTENANCE, 

REBUILDING, AND ALTERATION 

■ 12. The authority citation for part 43 

is revised to read as follows: 

Authority: 42 U.S.C. 7572; 49 U.S.C. 106(f), 

106(g), 40105, 40113, 44701–44702, 44704, 

44707, 44709, 44711, 44713, 44715, 45303. 

■ 13. In part 43, appendix E, revise the 

introductory text and paragraph (a)(2) to 

read as follows: 

Appendix E to Part 43—Altimeter 

System Test and Inspection 

Each person performing the altimeter 

system tests and inspections required by 

§ 91.411 must comply with the 

following: 

(a) * * * 

(2) Perform a proof test to demonstrate 

the integrity of the static pressure 

system in a manner acceptable to the 

Administrator. For airplanes certificated 

under part 25 of this chapter, determine 

that leakage is within the tolerances 

established by § 25.1325. 

* * * * * 

PART 91—GENERAL OPERATING AND 

FLIGHT RULES 

■ 14. The authority citation for part 91 

continues to read as follows: 

Authority: 49 U.S.C. 106(f), 106(g), 1155, 

40101, 40103, 40105, 40113, 40120, 44101, 

44111, 44701, 44704, 44709, 44711, 44712, 

44715, 44716, 44717, 44722, 46306, 46315, 

46316, 46504, 46506–46507, 47122, 47508, 

47528–47531, 47534, articles 12 and 29 of the 

Convention on International Civil Aviation 

(61 Stat. 1180), (126 Stat. 11). 

■ 15. In § 91.205, revise paragraphs 

(b)(13) and (b)(14), and remove 

paragraph (b)(16) to read as follows: 

§ 91.205 Powered civil aircraft with 

standard category U.S. airworthiness 

certificates: Instrument and equipment 

requirements. 

* * * * * 

(b) * * * 

(13) An approved safety belt with an 

approved metal-to-metal latching 

device, or other approved restraint 

system for each occupant 2 years of age 

or older. 

(14) For small civil airplanes 

manufactured after July 18, 1978, an 

approved shoulder harness or restraint 

system for each front seat. For small 

civil airplanes manufactured after 

December 12, 1986, an approved 

shoulder harness or restraint system for 

all seats. Shoulder harnesses installed at 

flightcrew stations must permit the 

flightcrew member, when seated and 

with the safety belt and shoulder 

harness fastened, to perform all 

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13528 Federal Register / Vol. 81, No. 49 / Monday, March 14, 2016 / Proposed Rules 

functions necessary for flight 

operations. For purposes of this 

paragraph— 

(i) The date of manufacture of an 

airplane is the date the inspection 

acceptance records reflect that the 

airplane is complete and meets the 

FAA-approved type design data; and 

(ii) A front seat is a seat located at a 

flightcrew member station or any seat 

located alongside such a seat. 

* * * * * 

■ 16. In § 91.313, revise paragraph (g) 

introductory text to read as follows: 

§ 91.313 Restricted category civil aircraft: 

Operating limitations. 

* * * * * 

(g) No person may operate a small 

restricted-category civil airplane 

manufactured after July 18, 1978, unless 

an approved shoulder harness or 

restraint system is installed for each 

front seat. The shoulder harness or 

restraint system installation at each 

flightcrew station must permit the 

flightcrew member, when seated and 

with the safety belt and shoulder 

harness fastened or the restraint system 

engaged, to perform all functions 

necessary for flight operation. For 

purposes of this paragraph— 

* * * * * 

■ 17. In § 91.323, revise paragraph (b)(3) 

to read as follows: 

§ 91.323 Increased maximum certificated 

weights for certain airplanes operated in 

Alaska. 

* * * * * 

(b) * * * 

(3) The weight at which the airplane 

meets the positive maneuvering load 

factor n, where n = 2.1 + (24,000/(W + 

10,000)) and W = design maximum 

takeoff weight, except that n need not be 

more than 3.8; or 

* * * * * 

■ 18. In § 91.531, revise paragraphs 

(a)(1) and (a)(3) to read as follows: 

§ 91.531 Second in command 

requirements. 

(a) * * * 

(1) A large airplane or normal 

category level 4 airplane, except that a 

person may operate an airplane 

certificated under SFAR 41 without a 

pilot who is designated as second in 

command if that airplane is certificated 

for operation with one pilot. 

* * * 

(3) A commuter category airplane or 

normal category level 3 airplane, except 

that a person may operate those 

airplanes notwithstanding paragraph 

(a)(1) of this section, that have a 

passenger seating configuration, 

excluding pilot seats, of nine or less 

without a pilot who is designated as 

second in command if that airplane is 

type certificated for operations with one 

pilot. 

* * * * * 

PART 121—OPERATING 

REQUIREMENTS: DOMESTIC, FLAG, 

AND SUPPLEMENTAL OPERATIONS 

■ 19. The authority citation for part 121 

continues to read as follows: 

Authority: 49 U.S.C. 106(f), 106(g), 40103, 

40113, 40119, 41706, 42301 preceding note 

added by Pub. L. 112–95, Sec. 412, 126 Stat. 

89, 44101, 44701–44702, 44705, 44709– 

44711, 44713, 44716–44717, 44722, 44729, 

44732; 46105; Pub. L. 111–216, 124 Stat. 

2348 (49 U.S.C. 44701 note); Pub. L. 112–95, 

126 Stat. 62 (49 U.S.C. 44732 note). 

■ 20. In § 121.310, revise paragraph 

(b)(2)(iii) to read as follows: 

§ 121.310 Additional emergency 

equipment. 

* * * * * 

(b) * * * 

(2) * * * 

(iii) For a nontransport category 

turbopropeller powered airplane type 

certificated after December 31, 1964, 

each passenger emergency exit marking 

and each locating sign must be 

manufactured to meet the requirements 

of § 23.811(b) of this chapter in effect on 

June 16, 1994. On these airplanes, no 

sign may continue to be used if its 

luminescence (brightness) decreases to 

below 100 microlamberts. 

* * * * * 

PART 135—OPERATING 

REQUIREMENTS: COMMUTER AND 

ON DEMAND OPERATIONS AND 

RULES GOVERNING PERSONS ON 

BOARD SUCH AIRCRAFT 

■ 21. The authority citation for part 135 

continues to read as follows: 

Authority: 49 U.S.C. 106(f), 106(g), 41706, 

40113, 44701–44702, 44705, 44709, 44711– 

44713, 44715–44717, 44722, 44730, 45101– 

45105; Pub. L. 112–95, 126 Stat. 58 (49 U.S.C. 

44730). 

■ 22. In § 135.169, revise paragraphs (b) 

introductory text, (b)(6), and (b)(7), and 

add paragraph (b)(8) to read as follows: 

§ 135.169 Additional airworthiness 

requirements. 

* * * * * 

(b) No person may operate a small 

airplane that has a passenger seating 

configuration, excluding pilot seats, of 

10 seats or more unless it is type 

certificated— 

* * * * * 

(6) In the normal category and 

complies with section 1.(b) of Special 

Federal Aviation Regulation No. 41; 

(7) In the commuter category; or 

(8) In the normal category, using a 

means of compliance accepted by the 

Administrator equivalent to the 

airworthiness standards applicable to 

the certification of airplanes in the 

commuter category found in part 23 of 

this chapter through amendment 23–62, 

effective January 31, 2012. 

* * * * * 

Issued under authority provided by 49 

U.S.C. 106(f), 44701(a), 44703 and Pub. L. 

113–53 (127 Stat. 584; 49 U.S.C. 44704 note) 

in Washington, DC, on March 7, 2016. 

Dorenda D. Baker, 

Director, Aircraft Certification Service. 

[FR Doc. 2016–05493 Filed 3–9–16; 11:15 am] 

BILLING CODE 4910–13–P 

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