75736 Federal Register / Vol. 76, No. 232 / Friday, December 2, 2011 / Rules and Regulations 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 23 

[Docket No. FAA–2009–0738; Amendment 

No. 23–62] 

RIN 2120–AJ22 

Certification of Part 23 Turbofan- and 

Turbojet-Powered Airplanes and 

Miscellaneous Amendments 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: This action enhances safety 

by amending the applicable standards 

for part 23 turbofan- and turbojetpowered airplanes—which are 

commonly referred to as ‘‘part 23 jets,’’ 

or ‘‘jets’’—as well as turbopropellerdriven and reciprocating-engine 

airplanes, to reflect the current needs of 

industry, accommodate future trends, 

address emerging technologies, and 

provide for future airplane operations. 

This action is necessary to eliminate the 

current workload of processing 

exemptions, special conditions, and 

equivalent level of safety findings 

necessary to certificate jets. The effect of 

the changes will: Enhance safety by 

requiring additional battery endurance 

requirements; increase the climb 

gradient performance for certain part 23 

airplanes; standardize and simplify the 

certification of jets; clarify areas of 

frequent non-standardization and 

misinterpretation, particularly for 

electronic equipment and system 

certification; and codify existing 

certification requirements in special 

conditions for jets that incorporate new 

technologies. 

DATES: These amendments become 

effective January 31, 2012. 

FOR FURTHER INFORMATION CONTACT: For 

technical questions concerning this final 

rule, contact Pat Mullen, Regulations 

and Policy, ACE–111, Federal Aviation 

Administration, 901 Locust Street, 

Kansas City, MO 64106; telephone: 

(816) 329–4111; facsimile: (816) 329– 

4090; email: pat.mullen@faa.gov. For 

legal questions concerning this final 

rule, contact Mary Ellen Loftus, ACE–7, 

Federal Aviation Administration, 901 

Locust Street, Kansas City, MO 64106; 

telephone: (816) 329–3764; email: 

mary.ellen.loftus@faa.gov. 

SUPPLEMENTARY INFORMATION: 

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 

safety standards for the design of 

normal, utility, acrobatic, and commuter 

category airplanes. 

Table of Contents 

I. Background 

A. Aviation Rulemaking Committee (ARC) 

Recommendations 

B. Summary of the Notice of Proposed 

Rulemaking 

C. Summary of the Final Rule 

D. Summary of the Comments 

II. Discussion of the Final Rule 

A. 14 CFR Part 1: Clarifying Power and 

Engine Definitions 

B. Expanding Commuter Category To 

Include Turbojets 

C. Performance, Flight Characteristics, and 

Other Design Considerations 

D. Structural Considerations for 

Crashworthiness and High-Altitude 

Operations 

E. Powerplant and Operational 

Considerations 

F. General Fire Protection and 

Flammability Standards for Insulation 

Materials 

G. Additional Powerplant and Operational 

Considerations 

H. Additional Powerplant Fire Protection 

and Flammability Standards 

I. Avionics, Systems, and Equipment 

Changes 

J. Placards, Operating Limitations, and 

Information 

K. Test Procedures and Appendices 

III. Regulatory Analyses 

I. Background 

A. Aviation Rulemaking Committee 

(ARC) Recommendations 

On February 3, 2003, we published a 

notice announcing the creation of the 

part 125/135 Aviation Rulemaking 

Committee (68 FR 5488). The ARC 

completed its work in 2005 and 

submitted its recommendations to the 

FAA for safety standards applicable to 

part 23 turbojets. The ARC 

recommended modifying forty-one 14 

CFR part 23 sections as a result of its 

review of these areas. Those documents 

may be reviewed in the docket for this 

final rule. 

The safety standards are to reflect the 

current industry trends, emerging 

technologies and operations under parts 

125 and 135, and associated regulations. 

The ARC also reviewed the existing part 

23 certification requirements and the 

accident history of light pistonpowered, multiengine airplanes up 

through small turbojets used privately 

and for business purposes. In addition, 

the ARC reviewed the special 

conditions applied to part 23 turbojets. 

Based on those ARC 

recommendations, the FAA’s intent is to 

enhance safety and to codify standards 

consistent with the level of safety 

currently required through special 

conditions. We compared the special 

conditions applied to part 23 turbojets, 

as well as several additional proposed 

part 23 changes, with the ARC’s 

recommendations. With few exceptions, 

the ARC recommendations validated the 

FAA’s long-held approach to 

certification of part 23 turbojets. 

The ARC did not want to impose 

commuter category takeoff speeds for 

turbojets weighing more than 6,000 

pounds, nor did the ARC want to 

impose more stringent requirements for 

one-engine inoperative (OEI) climb 

performance than those established for 

similar-sized piston-powered and 

turboprop, multiengine airplanes. The 

FAA ultimately accepted thirty-nine of 

the forty-one ARC recommendations 

and developed the proposed rulemaking 

in accordance with them. The two 

recommendations we disagreed with 

would have lowered the standards 

previously applied through special 

conditions. 

B. Summary of the Notice of Proposed 

Rulemaking 

The FAA issued the notice of 

proposed rulemaking (NPRM), 

‘‘Certification of Turbojets,’’ on August 

6, 2009 and published it for public 

comment on August 17, 2009 (74 FR 

41556). The comment period for the 

NPRM closed on December 16, 2009 

after a one-month extension. 

The FAA proposed the adoption of 67 

new or revised amendments in the 

NPRM. The amendments were proposed 

to codify previous certification activity. 

C. Summary of the Final Rule 

This final rule adopts 59 of the 67 

proposed amendments. We have also 

amended §§ 23.65 and 23.1431 in this 

final rule based on comments received. 

Changes to § 23.65 make it consistent 

with the changes made to § 23.63. 

Editorial changes to § 23.1431 are based 

on paragraph designation changes to 

§ 23.1309. 

This final rule mainly levies new 

regulations for part 23 jets. These new 

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regulations generally fall into the 

following categories: 

• Airplane flight performance and 

stability 

• Airplane structural and cabin 

environment 

• Airplane avionics systems and 

electrical equipment 

• Powerplant considerations 

• Flammability standards 

The majority of this final rule allows 

manufacturers of jets to achieve product 

certification without the numerous 

special conditions, equivalent level of 

safety (ELOS) findings, and exemptions 

previously required to certificate these 

products. Therefore, this final rule 

reduces the certification burden on the 

applicant and allows the FAA to focus 

resources on other safety-critical items. 

In addition, this final rule enhances 

safety by requiring additional battery 

endurance requirements and increasing 

the climb gradient performance for 

certain part 23 airplanes. 

D. Summary of the Comments 

The FAA received 244 substantive 

comments from 14 commenters. All of 

the commenters generally supported the 

proposed changes. The comments 

included suggested changes, which are 

discussed more fully below in Section 

II, Discussion of the Final Rule. 

The FAA received no comments on 

the following sections, and they are 

adopted as proposed or with minor 

editorial changes: 

• 23.77, Balked landing 

• 23.853(d)(2), Passenger and crew 

compartment interiors 

• 23.1303(c), Flight and navigation 

instruments 

• 23.1445, Oxygen distribution system 

• 23.1447, Equipment standards for 

oxygen dispensing units 

• 23.1545, Airspeed indicator 

• 23.1555, Control markings 

• 23.1559, Operating limitations 

placard 

• 23.1563, Airspeed placards 

• 23.1567, Flight maneuver placard 

The FAA received comments from 

manufacturers, foreign aviation 

authorities, and industry associations. 

No commenters recommended 

withdrawing the NPRM. Most of the 

commenters provided suggestions for 

improvement or requested clarification 

of specific proposed amendments. Some 

commenters recommended that several 

proposed amendments (or portions of 

them) not be adopted. However, 

objection to one proposed amendment 

did not equate to overall objection to the 

NPRM. 

The following areas are the key 

concerns expressed by industry: 

• Mandating software and complex 

hardware development assurance 

levels 

• Requirement for electronic engine 

controls to meet the requirements of 

§ 23.1309 ‘‘Equipment, systems and 

installations’’ 

• Subpart B, Flight, and Subpart G, 

Operating Limitations and 

Information 

• Requirement for ‘‘two shot’’ fire 

extinguishing systems for engines 

embedded within the fuselage 

• Codifying high-altitude operations 

• Requirements for electronic displays 

in part 23 airplanes 

• Part 1 definitions (§ 1.1) 

The FAA also received comments 

regarding FAA policy, means of 

compliance, and suggested changes to 

advisory circulars and regulations not 

included in the NPRM. These comments 

are considered to be beyond the scope 

of this rulemaking effort. No further 

discussion of them occurs in this final 

rule. 

II. Discussion of the Final Rule 

A. 14 CFR Part 1: Clarifying Power and 

Engine Definitions 

The FAA proposed to amend § 1.1 

definitions for ‘‘rated takeoff power,’’ 

‘‘rated takeoff thrust,’’ ‘‘turbine engine,’’ 

‘‘turbojet engine,’’ and ‘‘turboprop 

engine.’’ Defining engine-specific terms 

was proposed to clarify the new 

requirements in part 23. 

Communications between the FAA and 

members of industry indicated a need to 

define those terms. These 

communications were mainly based on 

current part 1 definitions for ‘‘rated 

takeoff power’’ and ‘‘rated takeoff 

thrust,’’ which currently limit the use of 

power and thrust ratings to no more 

than five minutes for takeoff operation. 

The FAA received comments from 

Rolls Royce, Transport Canada, General 

Electric (GE), and the European 

Aviation Safety Agency (EASA) 

objecting to the proposed definitions. 

The FAA agrees with the commenters 

that ‘‘rated takeoff power,’’ ‘‘rated 

takeoff thrust,’’ ‘‘turbine engine,’’ 

‘‘turbojet engine,’’ and ‘‘turboprop 

engine’’ are not used consistently in 

Title 14, Code of Federal Regulations 

(14 CFR). 

Defining engine types—whether 

turbine-powered (turbine), turbojetpowered (turbojet), or turbopropellerdriven (turboprop)—is unnecessary 

because they are commonly understood 

by those within industry. However, the 

commenters make a valid point 

regarding changes to the definitions for 

‘‘rated takeoff power’’ and ‘‘rated takeoff 

thrust.’’ These terms may not 

necessarily be accepted for use in part 

25, and as such, should not be defined 

under § 1.1. 

The Engine and Propeller Directorate 

is currently working to establish 

common definitions for ‘‘rated takeoff 

power’’ and ‘‘rated takeoff thrust’’ that 

would apply to both part 23 and part 25 

airplanes. The proposals to add these 

definitions are withdrawn to allow the 

Engine and Propeller Directorate time to 

complete its work on this effort. 

B. Expanding Commuter Category to 

Include Jets 

The FAA proposed to revise § 23.3 to 

codify the current FAA practice of 

certificating multiengine jets weighing 

up to and including 19,000 pounds 

under part 23 in the commuter category. 

Prior amendments to part 23 limited 

§ 23.3 commuter category to propellerdriven, multiengine airplanes weighing 

no more than 19,000 pounds. However, 

the FAA issued exemptions to allow jets 

weighing more than 12,500 pounds to 

be certificated under part 23, commuter 

category. 

The FAA received comments from 

Transport Canada and EASA. Transport 

Canada proposed that jets with seating 

capacity of 10 or more (excluding pilot 

seats), or maximum certificated take-off 

weight of more than 12,500 pounds, 

continue to be certificated using part 25 

transport category requirements in 

Subpart B: Performance. EASA 

suggested the rule pertain to ‘‘high 

performance’’ rather than ‘‘multiengine’’ 

airplanes. 

The FAA did not adopt either 

comment. Transport Canada’s comment 

was not adopted because part 23, 

Subpart B has been shown to be an 

acceptable means of compliance for 

airplanes weighing up to 19,000 

pounds. This final rule retains that 

weight limit. EASA’s comment was not 

adopted because ‘‘high performance’’ is 

an undefined, subjective term relative to 

airplane certification. Therefore, § 23.3 

is adopted as proposed. 

C. Performance, Flight Characteristics, 

and Other Design Considerations 

1. Performance 

The FAA proposed to incorporate in 

part 23 the current special conditions 

approach for jets weighing more than 

6,000 pounds by applying most 

commuter category performance 

requirements. The proposed revisions to 

§ 23.45 would apply the commuter 

category performance requirements for 

the normal, utility, and acrobatic 

categories to multiengine jets weighing 

more than 6,000 pounds. 

As a general matter, several 

commenters recommended replacing 

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the proposed propulsion-based criteria 

with performance-based criteria. The 

FAA agrees, as indicated in the Small 

Airplane Directorate’s Certification 

Process Study from 2009 which 

recommends revising part 23 based on 

airplane performance and complexity 

versus propulsion and weight. However, 

amending part 23 to a performancebased standard is a substantially larger 

initiative than this rulemaking effort. 

During rulemaking discussions, the 

ARC decided that applying the 

commuter category takeoff performance 

requirements in proposed revisions to 

§§ 23.51 through 23.61 would include 

restrictions that could become a takeoff 

weight limitation for operations. The 

concern was that these requirements 

would be too restrictive for part 91 

operations. 

The FAA disagreed with the ARC 

concerning multiengine jets weighing 

more than 6,000 pounds. The FAA has 

several decades of experience applying 

existing special conditions to part 23 

jets. The performance requirements for 

these jets have proven successful for 

part 91 operations and are necessary to 

maintain the existing level of safety. 

We received three comments 

regarding this proposal. EASA 

supported the changes and suggested 

requirements be extended to all jets, not 

just to those weighing more than 6,000 

pounds. Diamond Aircraft (Diamond) 

asked why this rule did not apply to 

turboprops and piston-powered 

airplanes. Transport Canada proposed 

that the all-engines-operating acceleratestop distance be determined in addition 

to the one-engine inoperative (OEI) 

distance, and the greater of the two be 

used as the accelerate-stop distance. 

Again, the Small Airplane 

Directorate’s Certification Process Study 

from 2009 recommends revising part 23 

based on performance and complexity 

versus propulsion and weight. We have 

not yet proposed to completely rewrite 

part 23, and doing so would be beyond 

the scope of this rulemaking. 

Accordingly, no change was made to the 

proposal in this final rule, except to 

change the word ‘‘turbojet’’ to ‘‘jet’’ 

wherever appropriate in this final rule. 

The FAA proposed revisions to 

§§ 23.63 and 23.67 to enhance safety by 

increasing the OEI climb gradient 

performance for multiengine pistonpowered airplanes weighing more than 

6,000 pounds and for all multiengine 

turbines. We proposed no change to the 

current 2 percent OEI climb gradient 

that has been consistently applied via 

special condition for multiengine jets 

weighing more than 6,000 pounds. 

We proposed to revise the OEI climb 

gradient requirements to require a 1 

percent OEI climb gradient for all 

multiengine turboprops and 

multiengine piston-powered airplanes 

weighing more than 6,000 pounds. We 

did so because of the similarity in how 

these two types of airplanes are used. 

Multiengine jets weighing 6,000 pounds 

or less will be required to meet an OEI 

climb gradient of 1.2 percent with this 

revision. 

The FAA has revised § 23.63(c) and 

(d), and § 23.67(b) and (c) to reflect 

these changes to the climb gradient 

requirements. The FAA also made a 

minor editorial change to replace 

‘‘turbojet engine-powered’’ with ‘‘jet’’ 

wherever appropriate in this final rule 

to simplify the term. Table 1 

summarizes those changes: 

TABLE 1—ONE-ENGINE INOPERATIVE (OEI) CLIMB REQUIREMENTS TO 400 FEET ABOVE GROUND LEVEL AGL 

Multiengine category Current rule 

ARC’s 

recommendation 

(percent) 

FAA’s position in 

final rule 

(percent) 

Pistons > 6,000 lbs ............................................... Measurably positive .............................................. 1.0 1.0 

Turboprops ≤ 6,000 lbs ........................................ Measurably positive .............................................. 1.0 1.0 

Turboprops > 6,000 lbs ........................................ Measurably positive .............................................. 1.0 1.0 

Jets ≤ 6,000 lbs .................................................... Measurably positive .............................................. 1.0 1.2 

Jets > 6,000 lbs .................................................... 2.0% imposed through special conditions ........... 1.0 2.0 

The FAA received comments on 

§§ 23.63, 23.65, and 23.67 from 

Transport Canada, Hawker Beechcraft, 

and Diamond. Transport Canada stated 

that the proposed § 23.63 would conflict 

with the existing § 23.65. The FAA has 

accordingly revised § 23.65 for 

consistency. Hawker Beechcraft stated 

that the change from ‘‘must be 

measurably positive’’ to ‘‘may be no less 

than 1 percent’’ could reduce takeoff 

payload by a maximum of 900 pounds. 

This would limit the utility of a normal 

category turboprop under high-hot 

conditions with takeoff flaps. The FAA 

understands that leveling the turboprop 

requirements with certain jets will cause 

a loss of utility and market 

disadvantage. However, given similar 

missions (many in revenue service), 

turboprops should be held to a 

performance standard similar to that for 

jets. The FAA reviewed the current 

service history safety data for these 

airplanes. Based on this data, the FAA 

only required half the single-engine 

climb requirements of multiengine jets. 

Diamond stated that this makes sense 

to a certain degree if the reasoning 

behind it is that turbines are capable of 

better performance than piston-powered 

airplanes. However, Diamond asked if 

there is a need to require compensating 

features if the airplane cannot meet a 

reasonable climb gradient. Diamond 

also asked why the FAA would change 

to a safer engine type if history has not 

shown there to be a problem with the 

current engine type. Diamond further 

stated that this requirement should be 

consistent with those for turbines, with 

no distinction between jets and 

turboprops. The FAA partially agreed 

and, as stated above, adopted an OEI 

climb gradient of 1 percent. 

The FAA received a comment from 

GE on the economic benefit of improved 

climb performance. GE stated that the 

improved climb performance is not a 

new requirement, and it is currently 

imposed by special condition. Since 

that special condition is not changing— 

it is now only being levied by this final 

rule—GE asked how a safety benefit can 

be credited to the rule. 

The FAA believes that adding this 

special condition as a requirement in 

part 23 will not only have a safety 

benefit, but it will also enhance our 

efforts toward continued operational 

safety. Special conditions are aircraftspecific and have not been issued for 

every part 23 airplane. Section 23.67 

(and § 23.77, which was adopted 

without change) addresses the 

additional climb performance for all 

part 23 turbojets and turboprops. The 

additional climb performance 

requirements will apply to all new part 

23 turboprops and part 23 turbojets 

under 6,000 pounds, thereby increasing 

the operational safety of those newly 

certificated airplanes. 

In addition, special conditions 

increase paperwork and workload for 

FAA and industry. Also, they create 

uncertainty for the manufacturer during 

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design. By incorporating the improved 

climb performance into part 23, special 

condition paperwork will be reduced 

and, in effect, will allow FAA and 

industry resource leveraging towards 

other safety-critical endeavors in our 

goal of continued operational safety. 

In developing cost estimates for the 

NPRM, the FAA contacted members of 

the ARC to determine when and if 

special conditions were voluntarily 

accepted by industry. When a special 

condition is voluntarily accepted by 

industry, the FAA does not include the 

special condition(s) cost in the 

regulatory impact assessment (RIA). 

When industry informs the FAA that a 

special condition will impose costs on 

industry, as do §§ 23.67 and 23.77, the 

FAA estimates the incremental cost 

between the current and final rule. 

The FAA proposed to correct a 

reference error to a velocity term in 

§ 23.73. Maximum landing 

configuration stall speed (VSO) was 

changed to specified flap configuration 

stall speed (VS1). VSO is not applicable 

to other flap configurations. The 

reference landing approach speed (VREF) 

is based on 1.3 times the VS1. The FAA 

proposed to amend the standards to 

address airplanes certificated under part 

23 that may have more than one landing 

flap setting. Additionally, the FAA 

proposed to include multiengine jets 

weighing more than 6,000 pounds in the 

commuter category requirements. 

The FAA received one comment. 

Diamond stated that the distinction 

between jet engines and other engine 

types may not be appropriate. It 

suggested the requirement for a higher 

level of safety be related to performance, 

not to engine type. As stated earlier, the 

FAA has determined that amending part 

23 to a performance-based standard is a 

substantially larger initiative and 

beyond the scope of this rulemaking 

effort. 

2. Flight Characteristics 

In § 23.175(b), the FAA proposed to 

define the maximum speed for stability 

characteristics (VFC/MFC). The term VFC/ 

MFC was added to part 23 in the last 

large-scale revision to Subpart B, but the 

definition was inadvertently omitted. 

EASA commented on multiple 

proposed sections that it applies a 

special condition for high-speed 

characteristics that are not included in 

our proposal. EASA’s comments 

suggested these sections be drafted as a 

performance-based standard. However, 

amending part 23 to a performancebased standard is a substantially larger 

initiative than this rulemaking effort. 

The FAA also received comments 

from Transport Canada and Cessna 

regarding flight characteristics. Both 

commenters recommended that we 

include the definition of VFC/MFC in 

§ 23.253 for consistency with part 25. 

The FAA agrees and has relocated the 

definition for it from § 23.175 to 

§ 23.253. 

The FAA proposed revisions to 

§ 23.177 that would have clarified the 

specific speed limitations to include 

jets. The proposed speed limitations 

also included specific criteria (‘‘VFE, 

VLE, VNO or VFC/MFC as appropriate’’ as 

defined in Part 1). 

The FAA proposed to relax the 

stability requirements in § 23.181 for 

airplanes operating above 18,000. The 

original requirements were developed 

for small airplanes typically operated 

under 18,000 feet and not equipped 

with yaw dampers. The existing 

requirement is still appropriate for lowaltitude operations, such as for 

approaches. However, the existing 

requirement is not appropriate for larger 

airplanes that typically use yaw 

dampers and fly at altitudes above 

18,000 feet. In fact, the FAA has issued 

multiple ELOS findings for most 

certificated part 23 jets because such 

findings were appropriate for highaltitude, high-speed operations. 

The FAA received comments from 

EASA, Cessna, and Emivest. EASA 

commented in multiple sections that it 

applies a special condition for highspeed characteristic not included in our 

proposal. EASA’s comment suggests a 

performance-based standard. Amending 

part 23 to a performance-based standard 

is a substantially larger initiative than 

this rulemaking effort. 

Cessna suggested § 23.181 include a 

similar definition to the revised 

§ 23.177. The FAA agrees with Cessna’s 

comment and added that definition to 

§ 23.181. 

Emivest recommended that part 23 

allow the lower standard found in part 

25 for flight above 18,000 feet. The FAA 

disagrees with this recommendation. 

Part 23 airplanes are frequently flown 

by a single pilot and operated under 

part 91. Single pilots operating part 23 

airplanes may not necessarily have the 

same experience level as part 25 

airplane pilots. Therefore, the stability 

and control requirements in part 23 will 

remain higher than in part 25. 

We proposed revisions to the stall 

requirements in §§ 23.201 and 23.203 to 

include jets and a new generation of 

part 23 airplanes with high-power and 

high-altitude capability. 

The proposed revisions included: 

• Incorporating additional 

configurations for all part 23 airplanes; 

• Clarifying flap and gear position as 

appropriate for the altitude and flight 

phase; 

• Relaxing the roll-off requirements 

for high-altitude stalls; and 

• Defining what is meant by ‘‘extreme 

nose-high attitudes.’’ 

The FAA received comments from the 

General Aviation Manufacturers 

Association (GAMA) and Emivest. 

GAMA stated the requirement for the 

demonstration of control during entry 

and recovery from wings level stall is 

unnecessary above 1.5 VS1 instead of 1.6 

VS1, as this requirement matches the 

requirements applicable to part 25 

airplanes. The FAA agrees and has 

made the necessary change to be 

consistent with the requirements for 

part 23 jets. 

Emivest recommended the FAA allow 

the lower handling characteristic 

standards from part 25, specifically 

being able to control rolling from 15 to 

20 degrees of roll. The FAA does not 

believe that this is appropriate for all 

altitudes. Parts 23 and 25 still have a 

considerable number of stall/departure 

accidents at low altitudes, even with 

stall barrier devices. The FAA is moving 

part 23 towards even more benign stall 

characteristics and additional stall 

protection systems. 

The FAA determined that relieving 

the controllability requirements in 

§ 23.201 across the entire altitude 

capability would move part 23 in the 

wrong direction—inconsistent with 

current stall requirements. Considering 

that most stall accidents occur at low 

altitudes, this revision would relax the 

stall handling characteristic roll 

requirement to 25 degrees for stalls at or 

above 25,000 feet. We believe this is an 

acceptable action for this flight regimen 

for the class of airplane operating at or 

above 25,000 feet. 

The FAA proposed to incorporate 

provisions from §§ 25.251(d) and (e) 

into § 23.251 while limiting the 

requirements to airplanes that fly over 

25,000 feet or that have a Mach Dive 

Speed (MD) faster than Mach (M) 0.6. 

The proposed revision also included the 

use of VDF/MDF, as referenced in part 23 

jet special conditions. 

The FAA received similar comments 

from Cirrus and Transport Canada. 

Cirrus stated that § 23.251(b) and (c) use 

the term ‘‘perceptible buffeting,’’ which 

is a subjective term. Cirrus requested a 

concise term to differentiate ‘‘normal 

vibration’’ from ‘‘perceptible buffeting,’’ 

or a standard definition of ‘‘perceptible 

buffeting.’’ The FAA will address this 

comment in an advisory circular, which 

we believe is the appropriate place to 

address it. 

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1The FAA provided a history of the previous 

rulemaking effort in the NPRM. 74 FR 41522. 

Transport Canada stated that the use 

of operational speeds is considered 

more appropriate than using a design 

speed as criteria. The FAA understands 

the commenter’s point. For this 

situation, however, the FAA believes 

the part 23 speed rationale should 

parallel the rationale in part 25 for 

consistency in our decisions for 

continued aviation safety. 

The FAA revised § 23.253(b) to add 

the use of demonstrated flight diving 

speed (VDF/MDF) as applicable, 

consistent with standards in § 25.253. 

The FAA also moved the proposed 

definition for VFC/MFC from § 23.175 to 

this section as paragraph (d). 

The FAA proposed adding § 23.255 to 

include new requirements that consider 

potential high-speed Mach effects for 

airplanes with MD greater than M 0.6. 

The FAA proposed these requirements, 

which came from part 25, for airplanes 

that incorporate a trimmable horizontal 

stabilizer. This decision was based on 

the positive service history with the 

existing fleet of part 23 jets designed 

with conventional horizontal tails and 

those that use trimmable elevators. 

Airplanes that experienced upset 

incidents involving out-of-trim 

conditions were part 25 certificated 

airplanes and designed with a 

trimmable horizontal stabilizer. 

The FAA received a comment from 

Transport Canada, stating that this 

requirement should apply to all 

horizontal tail configurations as 

required for transport category 

airplanes. The FAA disagrees with 

Transport Canada. The highperformance airplanes that will be 

certificated under part 23 are similar to 

those that have established a positive 

service history using similar regulations; 

therefore, this final rule has not been 

changed as a result of this comment. 

D. Structural Considerations for 

Crashworthiness and High-Altitude 

Operations 

1. Design and Construction 

The FAA proposed changes to 

§ 23.561 to address structural 

requirements for engines contained 

within the fuselage and located behind 

the passenger cabin. The FAA proposed 

these changes to: (1) Add structural 

requirements to single-engine jets with 

centerline engines embedded in the 

fuselage, and (2) minimize the 

likelihood of the engine breaching the 

passenger compartment in the event of 

an emergency landing. The proposal 

would have reduced the potential for 

the engine to separate from its mounts 

under forward-acting crash loads and 

subsequently intrude into the passenger 

compartment (i.e., cabin). 

The FAA received several comments 

on this proposed change. EASA 

suggested the proposed rule should be 

expanded to include any engine 

mounted inside the fuselage and aft of 

the cabin, not just turbojet engines. The 

FAA agrees with EASA. Any engine 

mounted in this type of configuration 

may be a hazard to cabin occupants in 

the event of an emergency landing, so 

the regulation should not be limited to 

turbojet engines. The proposed 

amendment has been modified to 

capture this comment. 

Transport Canada stated that the 

proposed load factors should be 

adjusted upward if the VS0 of the 

airplane exceeds 61 knots. The FAA 

disagrees with Transport Canada since 

the proposed regulation would require 

the engine to be retained at 18 g in 

combination with maximum takeoff 

thrust. This approach is reasonable for 

engine retention. 

Transport Canada also stated that the 

attached accessories need not be 

required to withstand the added load of 

maximum engine takeoff thrust since 

accessories do not react to engine thrust 

loads. The FAA disagrees with this 

comment. While engine accessories 

should not directly react to engine 

thrust loads, engine accessories impart a 

load to their mounting structure. This 

load is typically highest when the 

engine is producing maximum takeoff 

thrust. The intent of this rule is to 

ensure the engine and its accessories do 

not penetrate the cabin in an emergency 

landing. 

Transport Canada further stated that 

proposed § 23.561(e)(1)(ii), which in the 

relevant part states ‘‘to deflect the 

engine’’ may be too limited. The 

commenter suggested there are other 

methods an airplane designer may 

propose, such as an energy-absorbing 

bulkhead or barrier. We agree, and by 

adopting this comment, the rule will be 

more performance-based and preclude 

dictation of the airframe design. The 

FAA has changed this final rule 

accordingly. 

The FAA proposed changes to 

§ 23.562 to require dynamic seat testing 

for commuter category jets. The FAA 

also proposed changes to the Head 

Injury Criteria (HIC) calculation in 

§ 23.562 to be consistent with the HIC 

calculation contained in § 25.562. 

Our intent with the proposed rule was 

to codify a requirement that has become 

industry practice. All manufacturers of 

those recently certificated commuter 

category jets have agreed to comply with 

§ 23.562. It was not our intent to include 

commuter category propeller-driven 

airplanes in § 23.562 in light of the 

rulemaking history associated with that 

effort.1 The FAA has decided against 

adding commuter category propellerdriven airplanes to § 23.562 at this time. 

The FAA reserves the right, however, to 

reconsider this position in the future 

should adverse service history suggest 

changes are necessary. 

In addition, the FAA received 

comments from several organizations 

indicating a mistake in the proposed 

HIC calculation. The commenters stated 

that the proposed definition of ‘‘a(t)’’ 

would require calculating HIC for the 

entire head acceleration time, not just 

for the time of impact with interior 

components. The FAA agrees the 

proposed rule did not specify the word 

‘‘strike’’ when defining ‘‘a(t)’’ as the 

total acceleration versus the time curve 

for a head strike. The FAA has made the 

necessary changes to the definition of 

‘‘a(t)’’ in this final rule so it is clear that 

HIC is calculated for the head strike 

only. 

The NPRM included new sections in 

§§ 23.571, 23.573, and 23.574, which 

noted additional requirements 

referencing the new high altitude 

requirements of § 23.841(e). These 

additional requirements included the 

establishment of a Limit of Validity 

(LOV), as well as additional test 

requirements. Several commenters, 

including Cessna and GAMA, objected 

to the LOV concept due to the burden 

it could place on applicants. Upon 

consideration of these comments the 

FAA agrees we need additional time to 

consider the need for LOV. Therefore, 

we consolidated the requirements into 

§ 23.571(d) and removed the reference 

to § 23.841. Proposed § 23.841(e), which 

contained the LOV and additional test 

requirements, has been withdrawn. 

Section 23.571(d) still requires the 

damage tolerance option under § 23.573 

to be used on airplanes that exceed 

41,000 feet. Section 23.571(d) will also 

require that damage tolerance be used to 

evaluate structure for operations above 

41,000 feet on all airplanes except 

commuter category. Commuter category 

airplanes are already required to use 

damage tolerance under § 23.574. The 

FAA has modified § 23.571 as discussed 

and withdrawn the proposed revisions 

to §§ 23.573 and 23.574. 

In addition, GE stated it would be 

difficult to comply with the proposed 

§ 23.841, given all of the exemptions 

granted for this rule in the past. The 

FAA disagrees with this comment, but 

GE is correct that a number of 

exemptions have been granted. 

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However, all but one of the exemptions 

were for part 25 airplanes. This single 

part 23 airplane exemption dealt with 

the method of compliance for this rule. 

(See Exemption No. 5223; also, a copy 

of this exemption will be placed in the 

docket for this rulemaking.) 

As noted above, the proposed rule has 

been revised, and previous part 25 

exemptions are irrelevant to the subject 

part 23 airplanes. Several jets have 

successfully met depressurization 

profiles, thereby meeting appropriate 

part 23 certification requirements. 

The FAA proposed to clarify the use 

of either the MD or the Dive Velocity 

(VD) in § 23.629, whichever is 

appropriate, for jets. As dive speeds 

increase with high performance 

airplanes, the compressibility effects of 

the air become more significant; 

therefore, it is more appropriate to refer 

to MD instead of VD. Proposed changes 

would have also allowed the use of a 

‘‘demonstrated’’ flight dive speed (VDF/ 

MDF) instead of the theoretical speeds 

(VD/MD) when flight flutter testing jets. 

Using a demonstrated speed, in lieu of 

a theoretical speed, can relieve some 

compliance burden when an airplane is 

unable to attain those theoretical dive 

speeds during the test phase of an 

airplane certification program. 

Cessna stated that the FAA was 

attempting to align the part 23 small 

airplane flutter requirements with those 

of part 25 for transport category 

airplanes. The FAA does not agree with 

this summary of the change. While the 

change is similar to certain transport 

category requirements, there was no 

decision in this case to make this part 

23 requirement identical to part 25 

requirements. The FAA seeks only to 

establish a category-appropriate rule for 

jets which balances many factors; those 

factors include risk management, safety, 

and cost. 

Cessna stated that in one paragraph 

the FAA only made the change to add 

the Mach dive speed designation, but 

did not include the option for the 

demonstrated flight speeds. The FAA 

agrees with Cessna. It was inadvertently 

omitted from the proposed rule 

language. The FAA adopted that change 

in the final rule. 

Cessna further stated the proposal 

implied that the flutter analysis need 

only be performed to the demonstrated 

flight speed. The FAA agrees the 

wording was misleading and 

ambiguous. Therefore, the proposed 

language is revised to clarify that the 

flutter analysis must be performed to 20 

percent above the design dive speed or 

20 percent above the design Mach dive 

speed, whichever is appropriate. 

Additionally, § 23.629 is revised to 

clarify that the 20 percent margin above 

the design dive speed need not go above 

Mach 1.0, as this unnecessarily 

complicates the analysis. 

2. Other Design Considerations 

Proposed revisions to § 23.703 

introductory text and paragraph (b) 

would have added takeoff warning 

system requirements to all airplanes 

weighing more than 6,000 pounds and 

to all jets. The definition of an unsafe 

condition, in this case, is the inability 

to rotate or prevent an immediate stall 

after rotation. High temporary control 

forces that can be quickly ‘‘trimmed 

out’’ would not necessarily be 

considered unsafe. 

The FAA received two comments. 

EASA suggested the rule did not 

address all devices for a safe takeoff. 

Diamond asked why this rule did not 

apply to turboprops and piston-powered 

airplanes. 

Parking brakes and antiskid devices 

are optional installations and cannot be 

required by this rule; but if installed, 

optional installations can be included in 

the determination of an unsafe takeoff 

condition. Also, this rule applies to all 

airplanes weighing more than 6,000 

pounds and to jets of any weight. 

Therefore, turboprops and pistonpowered airplanes weighing more than 

6,000 pounds are included. The FAA 

inadvertently modified § 23.703(b) in 

the NPRM. Our intent was to add a new 

section, § 23.703(c). The FAA is 

adopting § 23.703(c) as originally 

intended and with a minor editorial 

change. 

The FAA changed the rejected takeoff 

requirements in § 23.735, which were 

previously only for commuter category 

airplanes, to be applicable for all 

multiengine jets weighing more than 

6,000 pounds. The higher takeoff speeds 

and distances for these airplanes make 

the ability to stop in a specified distance 

a safety issue. 

Two commenters suggested adding 

similar rejected requirements from part 

25. Adding these part 25 requirements, 

however, was not part of the NPRM. In 

this case, the part 25 requirements are 

too stringent for part 23 airplanes. We 

cannot justify those more stringent 

requirements based on our current 

service history. 

E. Powerplant and Operational 

Considerations 

Previous amendments to § 23.777 

standardized the height and location of 

powerplant controls because pilots may 

become confused and use the wrong 

controls on propeller-driven airplanes. 

However, previous amendments did not 

include single-power levers (which are 

typical for electronically-controlled 

engines). The FAA made an ELOS 

finding for each airplane program that 

included a single-power lever. Revised 

paragraph (d) in § 23.777 incorporates 

the ELOS language. 

The FAA received one comment that 

the requirement for power (thrust) 

levers should be easily distinguishable 

for human factor considerations instead 

of one inch higher than mixture and 

propeller levers. The FAA agrees with 

this comment and revised the rule to 

delete the one-inch requirement and 

changed the wording to easily 

distinguish the power levers from other 

controls. 

The FAA proposed to provide an 

alternative to meeting the requirement 

for an emergency exit above the 

waterline on both sides of the cabin for 

multiengine airplanes. The proposed 

change to § 23.807 allows the placement 

of a water barrier in the main cabin 

doorway before the door is opened as a 

means to comply with the above 

waterline exit requirement. This barrier 

is above the waterline and slows the 

water inflow, thus allowing exit through 

the main cabin door in a ditched 

airplane. The FAA approved the use of 

this barrier as an alternative to the above 

waterline exit for several airplanes by 

issuing an ELOS finding. 

The FAA received two comments. 

Emivest stated the rule language would 

permit a main cabin door below the 

waterline to be approved as an 

emergency exit. Embraer stated a water 

barrier should be allowed regardless of 

whether the main cabin door is above 

the waterline since the determination of 

the waterline is undefined. 

The FAA disagrees with both 

comments. The new § 23.807(e)(3) states 

‘‘may’’ because the new paragraph is an 

option for paragraph (e)(2), which 

specifies an overhead exit if side exits 

cannot be above the waterline. 

Furthermore, buoyancy analysis is 

standard practice to determine the 

waterline of an airplane. There is no 

reason to provide a water barrier if the 

emergency exit is above the waterline. 

Therefore, no changes were made to the 

proposal in this final rule. 

The FAA proposed amending § 23.831 

by adding new paragraphs (c) and (d), 

which would include standards 

appropriate for airplanes operating at 

high altitudes beyond those included in 

part 23. The changes were intended to 

ensure that flight deck and cabin 

environments do not result in the crew’s 

mental errors or physical exhaustion. 

Such an event would prevent the crew 

from successfully completing assigned 

tasks for continued safe flight and 

landing of an airplane. An applicant 

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may demonstrate compliance with 

paragraph (d) of this requirement if the 

applicant can show the flight deck 

crew’s performance is not degraded. 

Several new part 23 jet certification 

programs include approval for 

operations at altitudes above 41,000 

feet. Additionally, the FAA issued 

special conditions for operations up to 

49,000 feet and changed rules for 

structures and the cabin environment to 

ensure structural integrity of the 

airplane at higher altitudes. The FAA 

also made rule changes to prevent 

exposure of the occupants to cabin 

pressure altitudes that could cause them 

physiological injury or prevent the flight 

crew from safely flying and landing the 

airplane. 

The FAA intended the requirement 

‘‘* * * must not affect crew 

performance so as to result in a 

hazardous condition * * *’’ to mean 

the crew can reliably perform published 

and trained duties to complete a safe 

flight and landing. In the past, a 

person’s ability to track and perform 

tasks was measured by crew 

performance; however, acceptable crew 

performance is limited to the 

procedures defined by the manufacturer 

or required by existing regulations. The 

FAA uses ‘‘No occupant shall sustain 

permanent physiological harm’’ to 

describe the requirement that occupants 

who may have required some form of 

assistance must be expected to return to 

their normal activities once treated. 

Cirrus and Transport Canada stated 

the proposal, as written, applied to all 

phases of flight, including slow speed 

phases. The proposal was intended to 

apply to flight above 41,000 feet. The 

final rule for paragraphs (c) and (d) is 

changed to state the paragraphs are 

applicable only for the cruise phase of 

flight above 41,000 feet. 

Diamond suggested the rule should 

apply to all pressurized airplanes, not 

just to jets. The intent of the proposal 

was for it to apply to airplanes that 

operate above 41,000 feet. The FAA is 

unaware of any turboprops or pistonpowered airplanes that operate above 

41,000 feet. Special conditions would be 

applied to a turboprop or pistonpowered airplane with a maximum 

service ceiling above 41,000 feet. 

EASA stated two figures used for 

high-altitude airplanes, regarding the 

time temperature correlation, were not 

included. That oversight is corrected in 

this final rule. 

We proposed amending requirements 

in § 23.841 to prevent exposure of the 

occupants to cabin pressure altitudes 

that could keep the flight crew from 

safely flying and landing the airplane, or 

cause permanent physiological injury to 

the occupants. The changes provide 

airworthiness standards that allow 

subsonic, pressurized jets to operate at 

their maximum achievable altitudes— 

the highest altitude an applicant can 

choose to demonstrate the effects to 

several occupant-related items after 

decompression. The applicant must 

show that: (1) The flight crew would 

remain alert and be able to fly the 

airplane, (2) the cabin occupants are 

protected from the effects of hypoxia 

(i.e., deprivation of adequate oxygen 

supply), and (3) if some occupants do 

not receive supplemental oxygen, they 

are protected against permanent 

physiological harm. 

Several new part 23 jet certification 

programs include approval for 

operations at altitudes above 41,000 

feet. Additionally, we issued special 

conditions for operations up to 49,000 

feet. In this final rule, we changed rules 

for structures and the cabin 

environment to ensure structural 

integrity of the airplane at higher 

altitudes. 

Earlier amendments required the 

cabin pressure control system to 

maintain the cabin at an altitude of not 

more than 15,000 feet if any probable 

failure or malfunction in the 

pressurization system occurred. Cabin 

pressure control systems on part 23 

airplanes frequently exhibit a slight 

overshoot above 15,000 feet cabin 

altitude before stabilizing below 15,000 

feet. Existing technology for cabin 

pressure control systems on part 23 

airplanes cannot prevent this 

momentary overshoot, which prevents 

strict compliance with the rule. The 

FAA granted ELOS findings for this 

characteristic because physiological 

data show that the brief duration of the 

overshoot has no significant effect on an 

airplane’s occupants. 

Special conditions issued for part 23 

jets to operate at altitudes above 41,000 

feet are equivalent to the requirements 

in § 25.841 adopted in Amendment 25– 

87 (61 FR 28684, June 5, 1996). The 

amendment in this final rule modified 

§ 23.841 to include requirements for 

pressurized cabins previously covered 

only in special conditions. The special 

conditions required consideration of 

specific failures. Part 25 incorporated 

reliability, probability, and damage 

tolerance concepts addressing other 

failures and methods of analysis after 

the issuance of the special conditions. 

Sections 23.571, 23.573, and 23.574 

address the damage tolerance 

requirements. This final rule requires 

the use of these additional methods of 

analysis. 

Part 23 requires a warning of an 

excessive cabin altitude at 10,000 feet. 

Part 23 does not adequately address 

operations at airfield elevations above 

10,000 feet. Rather than disable the 

cabin altitude warning to prevent 

nuisance warnings, the FAA has issued 

ELOS findings allowing the warning 

altitude setting to be shifted above the 

maximum approved field elevation, not 

to exceed 15,000 feet. The FAA 

proposed to modify § 23.841 to 

incorporate language from existing 

ELOS findings into the regulation. 

The FAA received nine comments on 

this proposal. Several commenters 

disagreed with the structure of the 

initial proposed rule, the use of the 

noted damage tolerance principles, and 

the general systems rule for 

pressurization at high altitude. While 

EASA supported establishment of a 

Limit of Validity (LOV) and additional 

testing, Cessna, Embraer, and GAMA 

disagreed with the implementation of 

these concepts, which are not currently 

used in part 23. 

In response to comments from GAMA 

and Embraer, the FAA changed 

paragraph (b)(6)(ii) to permit a single 

operation for high altitude takeoffs and 

landings. In response to a comment 

from GE, paragraph (c)(2) is changed to 

exclude improbable failures. 

In addition, ruptures must be limited 

to control pressurized cabin breeches. 

Rapid pressure loss at high altitudes 

may result in physiological damage to 

the occupants. Section 23.841 defines 

acceptable depressurization profiles in 

such an event, and the pressurized 

structure serves as a part of the system 

to ensure the minimum cabin pressure 

is maintained. To control the cabin 

pressure vessel breeches in the fuselage 

structure, the noted damage tolerance 

principles are used (specifically 

borrowing the process referenced in 

§ 23.573(a) or (b)). 

F. General Fire Protection and 

Flammability Standards for Insulation 

Materials 

The FAA proposed upgrading 

flammability standards for thermal and 

acoustic insulation materials by adding 

a new § 23.856. The previous standards 

did not realistically address situations 

where thermal or acoustic insulation 

materials may contribute to producing a 

fire. The changes are based on the 

requirements in § 25.856(a) and part VI, 

Appendix F, which were adopted 

following accidents involving part 25 

airplanes, such as the Swissair MD–11. 

The proposed new standards would 

enhance safety by reducing the 

incidence and severity of cabin fires, 

particularly those in inaccessible areas 

where thermal and acoustic insulation 

materials are installed. 

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The proposed new standards also 

would include flammability tests and 

criteria that address flame propagation. 

They would apply to thermal/acoustic 

insulation material installed in the 

fuselage of part 23 airplanes. 

Prior amendments focus almost 

exclusively on materials located in 

occupied compartments (§ 23.853) and 

cargo and baggage compartments 

(§ 23.855). The potential for an in-flight 

fire is not limited to those specific 

compartments. Thermal/acoustic 

insulation can be installed throughout 

the fuselage in other areas, such as 

electrical or electronic compartments or 

surrounding air ducts, where the 

potential also exists for materials to 

spread fire. 

Proposed § 23.856 accounts for 

insulation installed within a specific 

compartment in areas the regulations 

might not otherwise cover and is 

applicable to all part 23 airplanes, 

regardless of size or passenger capacity. 

Advisory material describing test 

sample configurations to address design 

details (e.g., tapes and hook-and-loop 

fasteners) is available in DOT/FAA/AR– 

00/12, Aircraft Materials Fire Test 

Handbook, April 2000. 

Cessna stated this proposal should be 

limited to commuter category airplanes. 

The FAA disagrees because this hazard 

is not limited to commuter category 

airplanes. In addition, there has been a 

certification project to install this 

insulation in a normal category airplane. 

G. Additional Powerplant and 

Operational Considerations 

We inadvertently proposed to add 

requirements to § 23.903(b)(2) when we 

meant to propose a new paragraph 

(b)(3). This proposal was intended to 

protect passengers and maintain the 

ability for continued safe flight and 

landing following a fan disconnect 

event for fuselage-embedded, jet-engine 

installations. 

The FAA received six comments on 

this proposed rule change. Cirrus favors 

avoiding the use of the ‘‘embedded’’ 

classification altogether; the FAA does 

not. The crux of Cirrus’ position relates 

to the requirements for fire protection of 

embedded engines, and not protection 

against fan disconnect. Hawker 

Beechcraft, GE, and EASA commented 

on assessing the threat from fan 

disconnect questions as the means of 

compliance to this rule change. 

For each airplane with an embedded 

engine, the FAA will provide projectspecific guidance for an acceptable 

means of compliance regarding fandisconnect concerns. If the engine does 

not have a failure mode that results in 

a fan-disconnect event, then basic 

compliance would need to show the 

failure cannot occur. In this instance, no 

further showing of compliance would be 

required. Transport Canada supports the 

rule change. 

The FAA proposed adding a 

paragraph to § 23.1141 to require 

electronic engine control systems to 

meet the equipment, systems, and 

installation standards of § 23.1309. The 

FAA has applied this requirement to all 

digital engine control installations in 

part 23 airplanes by special condition 

for over ten years. The proposed rule 

change for § 23.1141 would have 

codified the requirements previously 

applied via special condition. 

The FAA received six comments on 

this proposed rule change. Most of the 

comments questioned the need for the 

specific application of § 23.1309 to 

electronic engine control systems. 

Diamond, GAMA, and Hawker 

Beechcraft stated that compliance was 

already required. Cessna stated there 

were similar requirements in 

§ 23.1141(e). GE stated there were no 

commensurate requirements in part 25, 

and that engine control was certificated 

in part 33. Transport Canada suggested 

the change should only address the 

electromagnetic environment and 

compatibility requirements, rather than 

all of § 23.1309. 

The FAA has not directly adopted 

these comments. However, the 

comments highlighted the difficulties in 

using § 23.1309 as the primary means by 

which to certificate electronic engine 

control system installation. There are 

conflicts between the guidance material 

for § 23.1309 and propulsion system 

certification. One example is a singleengine turbine-powered airplane with a 

failure of the electronic engine control 

system which cannot meet the failure 

probability commensurate with the 

hazard. As a result, applicants have 

elected to declare a reduced hazard 

severity of a failure of the electronic 

engine control system. This is not the 

intent of § 23.1309. The greater hazard 

severity should drive lower probability 

of failure, and the higher probability of 

failure should not drive the lower 

hazard severity. 

There is also a conflict between the 

hazard severity of a failure of an 

electronic engine control system and the 

required test levels for lightning and 

high intensity radiated frequency 

(HIRF). Testing to a level lower than 

required for a catastrophic failure 

results in a lower level of safety than the 

mechanical system it replaces. This is 

contrary to the intent of the certification 

requirements. As a result, the FAA 

decided to withdraw the proposed rule 

change and will continue to require the 

test levels via special conditions. 

We also proposed to expand the 

requirement in § 23.1165(f) for all 

turbine engine installations in 

commuter category airplanes, as it is 

currently limited to turboprops. The 

revision to the rule covers all turbines 

in the commuter category and removes 

the propeller driven restriction. (The 

definition of commuter category is also 

changed in § 23.3(d).) 

Transport Canada stated that the 

proposed rule conflicted with the gas 

turbine ignition systems for restarting an 

engine in flight, as required by 

§ 23.903(e)(3), (f) and (g). The FAA does 

not agree with this comment, as there is 

no conflict with the cited rules. Embraer 

suggested that the rule should be 

reworded to state ‘‘* * * each turbine 

engine ignition system must be 

considered an essential electrical load.’’ 

The FAA disagrees, as the suggested 

change does not change the substance of 

the rule. The proposal is adopted 

without change. 

H. Additional Powerplant Fire 

Protection and Flammability Standards 

When the FAA initially introduced 

powerplant fire protection provisions in 

part 23, jet engines were not embedded 

in the fuselage, or in pylons on the aft 

fuselage, for airplanes certificated to 

part 23 standards. Sections 23.1193, 

23.1195, 23.1197, 23.1199, and 23.1201 

added fire protection requirements for 

commuter category airplanes. 

Manufacturers also provide fire 

prevention through minimizing the 

potential for the ignition of flammable 

fluids and vapors. Historically, pilots 

were able to see engines and identify 

fires or use the incorporated fire 

detection systems, or both. The ability 

to see engines provided for the rapid 

detection of fires, which led to fires 

being rapidly extinguished. However, 

engine(s) embedded in the fuselage or in 

pylons on the aft fuselage do not allow 

the pilot to see a fire. 

For airplanes equipped with fuselageembedded engines, the consequences of 

a fire are more varied, adverse, and 

difficult to predict than an engine fire 

for a typical part 23 airplane. An engine 

embedded in the fuselage offers 

minimal opportunity to actually see a 

fire. Therefore, an engine’s location 

becomes critical to the ability to see and 

extinguish an engine fire. With fuselageembedded engines, an engine fire could 

affect both the airplane’s fuselage and 

the empennage structure, which include 

the pitch and yaw controls. A sustained 

fire could further result in the loss of 

airplane control before a pilot could 

make an emergency landing. 

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Transport Canada stated that a 

clarification for embedded engines 

would be useful. The FAA believes the 

term ‘‘embedded’’ is not confusing. A 

general definition of the term, which is 

to enclose closely in a surrounding 

mass, is adequate. Therefore, we do not 

provide further clarification of the term 

in this final rule. 

The FAA also proposed to change 

requirements in § 23.1195 for fire 

extinguishing systems, extinguishing 

agent containers, and fire extinguishing 

system materials. Diamond and Cirrus 

stated the issue is location of the 

engine(s) rather than the airplane 

category or type of engine. The FAA 

agrees and modified the rule to make it 

applicable to all part 23 airplanes with 

fuselage-embedded engines and to any 

part 23 airplanes with engines mounted 

in pylons on the aft fuselage. For 

embedded engine installations, a twoshot fire-extinguishing system would be 

required because the metallic 

components in the fire zone can become 

hot enough to reignite flammable fumes 

after extinguishing the first fire. 

GAMA, Cessna, and Cirrus objected to 

the requirement for a two-shot fire 

extinguishing system if an engine is 

embedded. Commenters had various 

reasons for their objections. However, 

while engines other than those 

embedded in a fuselage could reignite a 

fire, the hazard of fire damage to 

empennage flight controls or primary 

structure is greater for embedded 

engines than for other engine mounting 

installations. Cirrus also stated the rule 

change was not needed because small 

airplanes, including some jets, can 

descend and land in 15 minutes, as 

stated in the NPRM. 

We agree that some jets will likely be 

able to descend and land in 15 minutes 

without a problem, if an adequate 

airport is available. However, altitude is 

only one issue. These airplanes are 

approved for Instrument Flight Rules 

(IFR), so the ability to continue safe 

flight and landing also must consider 

time to descend under Air Traffic 

Control (ATC) through Instrument 

Meteorological Conditions (IMC) and 

make an approach and a go-around. 

Also, the ability to land off airport is an 

issue for an airplane with a 65 knot or 

higher stall speed. 

I. Avionics, Systems, and Equipment 

Changes 

The FAA proposed removing 

§ 23.1301(d) to improve standardization 

for systems and equipment certification, 

particularly for non-required equipment 

and non-essential functions embedded 

within complex avionic systems. EASA 

stated it will retain § 23.1301(d). 

Individuals also asked the FAA to retain 

this paragraph for non-required 

equipment and systems and intended 

functions. 

Section 23.1301(d) is directed towards 

environmental qualifications and 

operating conditions of the equipment 

and systems. The requirement in 

§ 23.1309(a) replaces the requirement in 

§ 23.1301(d) and, if § 23.1301(d) were 

retained, there would be a duplication 

of requirements. The requirement for 

intended function is further explained 

in §§ 23.1309(a)(1) and (a)(2) and the 

NPRM. 

Removal of § 23.1301(d) aligns with 

the proposed changes to § 25.1301(d) 

that was developed by the Joint 

Aviation Authorities (JAA) of Europe 

and the Aviation Rulemaking Advisory 

Committee (ARAC), which was 

established on January 22, 1991 (56 FR 

2190). We have decided to adopt this 

proposal without change. 

Proposed § 23.1305 would have 

eliminated the need for an ELOS finding 

for digital engine display parameters. It 

would have added requirements 

regarding usability for an ELOS finding. 

In addition, the ELOS finding would 

include the requirements for color 

indications for normal operation, 

operation in a caution range, and 

exceeding any limitation. These 

changes, however, were not part of the 

NPRM. Furthermore, there would still 

be a need for an ELOS finding for digital 

engine display parameters due to the 

digital indications being noncompliant 

with the requirements of § 23.1549. 

The FAA received seven comments. 

The FAA did not adopt these comments 

since the FAA is withdrawing the 

proposed change to § 23.1305. 

The FAA proposed § 23.1307 to 

require applicants to install the 

equipment necessary for anticipated 

operations (for example, operations 

identified in parts 91 and 135 and 

meteorological conditions). Cirrus, 

Embraer, and GAMA stated that the 

examples identified in proposed 

§ 23.1307 add little value and could 

increase burden on the manufacturer. 

The FAA agrees the certification 

applicant does not need to comply with 

the operational requirements of parts 91 

and 135 at the time of certification. 

Therefore, we are withdrawing this 

proposal. 

The FAA proposed changing the 

requirements for two different types of 

equipment and systems installed in the 

airplane. Section 23.1309 lists the 

qualifiers ‘‘under the airplane operating 

and environmental conditions.’’ This 

section also describes two actions for 

the applicant. First, the applicant must 

consider the full normal operating 

envelope of the airplane, as defined by 

the Airplane Flight Manual, with any 

modification to that envelope associated 

with abnormal or emergency procedures 

and any anticipated crew action. 

Second, the applicant must consider the 

anticipated external and internal 

airplane environmental conditions, as 

well as any additional conditions where 

equipment and systems are assumed to 

‘‘perform as intended.’’ 

Section 23.1309(a)(2) requires 

analysis of any installed equipment or 

system with potential failure condition 

that are catastrophic, hazardous, major, 

or minor to determine their impact on 

the safe operation of the airplane. The 

applicant must show that they do not 

adversely affect proper functioning of 

the equipment, systems, or installations 

covered by § 23.1309 and do not 

otherwise adversely influence the safety 

of the aircraft or its occupants. 

Section 23.1309(a)(2) does not 

mandate that non-required equipment 

and systems function properly during 

all airplane operations once in service, 

provided all potential failure conditions 

have no effect on the safe operation of 

the airplane. The equipment or system 

must function in the manner expected 

by the manufacturer’s operating manual 

for the equipment or system. An 

applicant’s statement of intended 

function must be sufficiently specific 

and detailed so that the FAA can 

evaluate whether the system is 

appropriate for the intended function(s). 

Garmin and Hawker Beechcraft stated, 

‘‘* * * radio frequency energy and the 

effects (both direct and indirect) of 

lightning strikes’’ should be removed 

from § 23.1309(a)(1). Their rationale is 

that there are specific requirements in 

§ 23.1308 for HIRF and for lightning in 

§§ 23.867 and 23.954. 

The NPRM included this phrase to 

replace the existing general 

requirements in § 23.1309(e) for the 

indirect effects of lightning. Since there 

is a specific HIRF requirement in 

§ 23.1308, the FAA agrees to remove the 

words ‘‘radio frequency.’’ Sections 

23.867 and 23.954 are requirements for 

the direct effects of lightning; therefore, 

the FAA also agrees to remove the word 

‘‘direct.’’ 

Several months after the FAA issued 

the NPRM for this rule, the FAA issued 

an NPRM (75 FR 16676, April 2, 2010) 

proposing specific requirements for the 

indirect effects of lightning in proposed 

§ 23.1306. The FAA plans to keep the 

requirement for indirect effects of 

lightning in § 23.1309(a)(1) until that 

final rule publishes. 

GAMA and Garmin suggested deleting 

the phrase ‘‘or systems whose improper 

function could reduce safety’’ in 

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§ 23.1309(a)(1). However, they agree to 

the explanation of the requirements in 

the preamble of the NPRM. They also 

stated the rule would be challenging to 

comply with since proposed 

§ 23.1309(b) deals with failure 

conditions such as the effects of 

malfunctions. The FAA agrees and has 

removed the phrase. 

Several commenters stated that 

§ 23.1309(a)(2) should be revised by 

replacing the beginning phrase ‘‘Those 

required for type certification or by 

operating rules and other’’ with ‘‘Any.’’ 

This revision is not a substantive 

change, and the FAA has revised the 

phrase as requested. 

Cessna and Garmin stated that the 

safety assessment process in proposed 

§ 23.1309(b) should not supersede the 

HIRF requirements of § 23.1308 and 

proposed § 23.1306, electrical and 

electronic system lightning protection. 

They also stated that the environmental 

effects, such as HIRF and lightning, 

should not be considered in 

combination with another single failure 

or pre-existing latent failure. The FAA 

agrees. 

We proposed that § 23.1309(a)(3) be 

applicable for all functional reliability, 

flight testing, or flight evaluations. 

Proposed § 23.1309(a)(3) was revised to 

be applicable during Type Inspection 

Authorization (TIA) and FAA flightcertification testing. 

Proposed § 23.1309(a)(3) is being 

changed to § 23.1309(b) in this final 

rule. Cessna, Embraer, and Garmin 

stated that the probability requirements 

were not appropriate for typical 

certification flight test, but portions of 

the preamble material are appropriate 

for advisory material. They also 

commented that root cause analysis and 

corrective action is the current industry 

practice and should be reflected in the 

rule. The FAA does not intend for the 

probability requirements, based on 

random distribution across a fleet of 

aircraft, to be applied on the beginning 

phase of operation. The FAA accepted 

these comments and modified proposed 

§ 23.1309(b) in this final rule. This 

section was revised to be applicable 

during TIA and FAA flight-certification 

testing. This requirement now reads: 

‘‘Minor, major, hazardous, or 

catastrophic failure condition(s), which 

occur during TIA or FAA flightcertification testing, must have root 

cause analysis and corrective action.’’ 

The FAA expects the applicant to 

show the system does not exhibit 

unintended or undesirable failure 

conditions that are minor, major, 

hazardous, or catastrophic. Guidance 

will be provided in AC 23.1309–1E. 

Garmin stated that the FAA removed 

the catastrophic failure condition 

limitation for the Visual Flight Rules 

(VFR) airplane from proposed 

§ 23.1309(b) without explanation. We 

removed this limitation since airplanes 

limited to VFR operation may have 

technologies that were not envisioned 

when Amendment 23–41 was 

developed. The advanced complex 

technologies now being installed also 

need to undergo the system safety 

assessment process. 

Several proposed amendments to 

introductory text for § 23.1309 and 

Appendix K would have codified a 

long-established means of compliance 

with current equipment, systems, and 

installations requirements. We also 

proposed updating failure condition(s) 

terminology used in related system 

safety assessment documents developed 

by industry working groups (e.g., RTCA 

and the Society of Automotive 

Engineers (SAE)). Some of this material 

identifies four classes of airplanes, as 

defined in Appendix K, and applies 

appropriate probability values and 

development assurance levels for each 

class. The FAA added this material as 

proposed requirements in the NPRM 

due to problems with one significant 

certification program. 

EASA stated that the proposed 

requirements and current requirements 

are applicable and no hierarchy is 

implied. EASA also stated that both 

specific and general requirements 

should apply, and the exceptions to 

other requirements should be listed. 

Time and the often case-by-case nature 

of exceptions do not permit the FAA to 

list all (potential) exceptions for 

§ 23.1309. The FAA has withdrawn the 

proposed exceptions from § 23.1309 but 

will list some of them in AC 23.1309– 

1E. The FAA will determine and 

consider additional exceptions in future 

revisions of AC 23.1309. Until then, 

applicants and certification authorities 

should contact the FAA, Small Airplane 

Directorate for approval of additional 

exceptions. 

Boeing, Cessna, Cirrus, Diamond, 

Embraer, GAMA, Garmin, GE, and 

Hawker Beechcraft stated that the 

guidance and clarification to proposed 

sections and Appendix K should not be 

regulatory text and should only be in 

the guidance material of AC 23.1309– 

1E. They stated that most of these 

proposed changes would result in more 

confusion and less standardization. 

They also asserted that there would be 

more exemptions, ELOS findings, and 

complicated compliance demonstrations 

with no safety benefit. As such, this 

would cause additional burden, 

inefficiencies, and cost. The 

commenters further asserted that having 

this material available only as guidance 

would allow the applicant to choose an 

alternative to the proposed requirements 

as a means of compliance. 

The FAA acknowledges that there has 

not been a problem with most 

applicants using this material as a 

means of compliance when only using 

AC 23.1309–1D, except for one typecertification program. Therefore, the 

FAA has decided not to proceed with 

the pertinent proposed amendments to 

§ 23.1309(b)(4), (b)(5), (c), (d), and (e) 

and will also not codify Appendix K. As 

requested, this material will remain 

available as a means of compliance in 

AC 23.1309–1E. Proposed §§ 23.1309 

(b)(1), (b)(2), and (b)(3) are now 

redesignated as §§ 23.1309(c)(1), (c)(2), 

and (c)(3) since proposed § 23.1309(a)(3) 

is redesignated as § 23.1309(b) in this 

final rule, as discussed above. 

Cirrus stated that note 5 in figure 2 of 

AC 23.1309–1C/D, should also be in 

Appendix K. Neither Appendix K nor 

figure 2 of AC 23.1309–1E contained 

note 5 as AC 23.1309–1C/D did. Note 5 

allows an additional reduction of 

Development Assurance Level (DAL) for 

Navigation, Communication, and 

Surveillance Systems if an altitude 

encoding altimeter transponder is 

installed and it provides the appropriate 

mitigations. 

This note was deleted since it was 

misused, and it is not appropriate to use 

a transponder as mitigation. If the 

transponder is actually providing 

mitigations for failure conditions, then 

the note is unnecessary for the system 

assessment process. Note 5 is removed 

from AC 23.1309–1E and, as stated 

above, the proposal to codify Appendix 

K is withdrawn. 

GE stated that the implementation of 

the four classes of airplanes, in 

Appendix K of the NPRM, has a sliding 

scale of acceptable risk/severity. That 

scale depends on airplane category, and 

it introduces inconsistency with other 

rules. GE believes this may lead to 

confusion of different numeric 

interpretations depending on the size of 

the airplane. 

The FAA developed the four classes 

of airplanes in AC 23.1309–1C over 

10 years ago for the implementation of 

modern avionics that provide safety 

benefits in part 23 airplanes. History has 

shown that developing the four classes 

improves safety, without confusion, due 

to the new features on electronic 

systems being installed. The aviation 

industry as a whole is on the threshold 

of a revolutionary change in 

communication, navigation, and 

surveillance of aircraft operations. The 

four-class certification criteria have 

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been shown to be beneficial for new 

technologies and affordable for General 

Aviation. The FAA considers the fourclasses more appropriate for an advisory 

circular and has decided to retain the 

four classes of airplanes in AC 23.1309– 

1E and to remove Appendix K. 

The FAA proposed revising 

§ 23.1309(f) to make it compatible with 

the current § 23.1322 (‘‘Warning, 

caution, and advisory lights’’), which 

distinguishes between caution, warning, 

and advisory lights installed on the 

flight deck. Other paragraphs were 

deleted from this section, as mentioned 

earlier; therefore, § 23.1309(f) has been 

redesignated as § 23.1309(d). Rather 

than only providing a warning to the 

flight crew, which is required by the 

current rule, newly redesignated 

§ 23.1309(d) requires that information 

concerning an unsafe system operating 

condition(s) be provided to the flight 

crew. 

Section 23.1309(d) also specifies that 

the design of systems and controls, 

including indications and 

annunciations, must reduce crew errors 

that could create more hazards. The 

additional hazards to be minimized 

include those caused by inappropriate 

actions by a crewmember in response to 

the failure, or those that could occur 

after a failure. 

The FAA proposed a new § 23.1310 

that was previously part of § 23.1309. 

The proposed change would not have 

changed the current requirements; the 

only change would have been the new 

section designation. 

In the past, § 23.1309 and § 25.1309 

had the same power source 

requirements. Then, there was a 

proposal for part 25 to move these 

requirements from § 25.1309 to 

§ 25.1310 without change. In 

Amendment 25–123 (72 FR 63405, 

November 8, 2007), the proposed 

requirements were changed for 

clarification without substantial changes 

to the requirements. 

GAMA suggested a revision for 

clarification. Therefore, the FAA made a 

change to § 23.1310 in the final rule by 

adopting the requirements in § 25.1310. 

This will also provide consistency in 

our standards. 

The FAA also proposed amendments 

for plain language purposes. Transport 

Canada stated the word ‘‘instrument,’’ 

which appears in several section titles 

in part 23, should be replaced with 

‘‘indications.’’ The FAA disagrees and 

maintains that the use of the word 

‘‘instrument’’ is clear and appropriate. 

GAMA stated the requirements in 

§ 23.1311(a)(5) should only be 

applicable when part 23 airplanes are 

operating in IFR conditions. GAMA also 

noted that some of the equipment listed, 

like attitude, is not required for Visual 

Flight Rules (VFR). The FAA agrees 

attitude instruments are not required for 

VFR operations under part 91. 

The redundancy requirements for 

some flight instruments or indicators 

may be too restrictive for airplanes 

limited to VFR operations only. This has 

caused several applicants to request an 

ELOS from § 23.1311(a)(5) for 

installation approval of electronic 

displays in part 23 airplanes limited to 

VFR operations only. The FAA agrees 

with this comment since it would 

reduce the burden of processing 

multiple ELOS findings. 

We proposed clarifying the 

requirements for ‘‘sensory cues’’ in 

§ 23.1311(a)(6). We also proposed 

amending § 23.1311(a)(7) to make 

acceptable instrument markings on 

electronic displays equivalent to those 

instrument markings on conventional 

mechanical and electromechanical 

instruments. Several commenters 

suggested minor changes to the 

requirements for clarification. The FAA 

agrees with most of these changes and 

has made them in this final rule. 

The FAA proposed amending 

§ 23.1311(b) by replacing the phrase 

‘‘remain available to the crew, without 

need for immediate action’’ with ‘‘be 

available within one second to the crew 

by a single pilot action or by automatic 

means.’’ This proposal would allow an 

applicant to take credit for reversionary 

or secondary flight displays on multifunction flight displays that provide a 

secondary means of primary flight 

information. 

Embraer stated the one-second 

requirement in § 23.1311(b) should be 

limited to the display of attitude. The 

FAA disagrees but acknowledges that in 

most current certifications of part 23 

airplanes, the attitude is the only 

information considered essential for 

continued safe flight and landing. The 

FAA does not want to limit the onesecond requirement to only attitude. 

With the expansion of future advanced 

technologies, some airplanes may have 

other information essential for 

continued safe flight and landing. 

GAMA, Cessna, and Garmin 

commented on making minor changes to 

proposed § 23.1311 for clarification. We 

incorporated most of these changes. 

Garmin suggested other minor 

recommendations to the NPRM. We also 

accepted most of these 

recommendations. They will be 

reflected in AC 23.1311–1C. 

To meet the jet performance 

requirements in Subpart B, the pilot 

needs accurate speed indicators while 

accelerating on the runway. We 

proposed revisions to add the 

requirement to calibrate the airspeed 

system down to 0.8 of the minimum 

value of V1. We also proposed the 

language used in part 25 for this same 

requirement because it is more in line 

with operating new part 23 jets. 

Diamond asked why this requirement 

is specific to jets and commuter category 

aircraft. Additionally, Diamond found 

the wording used in proposed 

§ 23.1323(e) confusing and suggested 

that it be reworded. If the intent is to 

keep this rule applicable to multiengine 

and commuter jets, then the commenter 

recommends removing the words 

normal, utility, and acrobatic (which 

represent the different categories of 

aircraft). 

The requirement in the prior 

amendment for § 23.1323(e) was 

applicable to the commuter category 

because only those part 23 airplanes 

were required to be certificated for 

accelerate-stop testing. The proposed 

amendment changed § 23.55 to require 

accelerate-stop testing for multiengine 

jets weighing more than 6,000 pounds, 

as well as commuter category airplanes. 

A multiengine airplane can be 

commuter category, but it may also be 

in the normal, utility, or the acrobatic 

category. This final rule will clarify that 

all multiengine jets weighing more than 

6,000 pounds are subject to acceleratestop testing, regardless of category or 

whether it is a turboprop or jet. This 

final rule also adds the requirement to 

calibrate the airspeed system down to 

0.8 of the minimum value of V1. 

Changes to pitot heat indication 

systems requirements in § 23.1326 were 

not included in the NPRM. Cessna 

stated that the previous rule required an 

amber light during startup and taxi 

when there was no safety issue. Since 

current annunciation systems provide 

the ability to change the annunciation of 

pitot heat during flight phases to amber, 

the rule should acknowledge the 

capability. Cessna suggested that the 

rule specify the following: ‘‘If a flight 

instrument pitot heating system is 

installed to meet the requirements 

specified in § 23.1323(d), an indication 

system must be provided to indicate to 

the flight crew when that pitot heating 

system is not operating during takeoff or 

in flight.’’ 

The FAA agrees, but the amber light 

must be operating except when the 

airplane is on the ground. However, 

since this comment is beyond the scope 

of the current rulemaking, the FAA did 

not include this change in the final rule. 

The FAA further proposed to change 

requirements for instruments that use a 

power source. Proposed § 23.1331 

would apply to instruments that rely on 

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a power source to provide required 

flight information for IFR operations. 

Independent power sources must be 

provided for these instruments or a 

separate display of the parameters that 

have a power source independent from 

the airplane’s primary electrical power 

system. Embraer requested clarification 

of § 23.1331(c)(2) without substantial 

change to the requirements. The FAA 

agrees and made those changes in this 

final rule. 

Cirrus stated that an additional 

heading display should not be required 

in § 23.1331(c)(2) for small general 

aviation aircraft since heading has a low 

safety criticality relative to altitude, 

attitude, and airspeed for this class of 

airplane. The FAA disagrees since an 

additional or separate display is not 

required if there are two independent 

power sources. Heading is an important 

parameter, and § 91.205 requires a 

stabilized heading source for IFR 

operations, in addition to the magnetic 

direction indicator. 

Proposed amendments for storage 

battery design and installation in 

§ 23.1353 would have added additional 

battery endurance requirements to 

enhance safety based on the airplane’s 

altitude performance. The proposal 

addressed the power needs of new allelectrical instruments, navigation and 

communications equipment, and engine 

controls. 

When those requirements were 

initially adopted, part 23 airplanes were 

mostly mechanical. All-electric, or 

almost all-electric airplanes were not 

envisioned. Previously, the FAA 

required 30 minutes of sufficient 

electrical power for a reduced or 

emergency group of equipment and 

instrumentation. The FAA considered 

30 minutes adequate to reach VFR 

conditions to continue flying to an 

adequate airport and to accomplish a 

safe landing for traditional part 23 

airplanes. 

Integrated electrical cockpits were 

also not envisioned during initial 

development of those requirements. 

Currently, new part 23 airplanes are 

being certificated with all-electrical 

instruments, including the standby 

instruments. This reliance on electric 

power has increased the importance of 

ensuring adequate battery power until 

the pilot can descend and make a safe 

landing. 

Most new turbine-powered airplanes, 

and some turbocharged, piston-powered 

airplanes, operate at high altitudes 

under IFR. Under these conditions, 30 

minutes may not be adequate for battery 

power because it would take more time 

to descend from maximum altitude to 

find visual meteorological conditions 

(VMC) and land, or to perform an 

instrument approach for a landing. For 

these reasons, the proposed requirement 

would extend the battery time 

requirement to 60 minutes for approved 

airplanes with a maximum operating 

altitude above 25,000 feet. The 30 

minute battery capacity was retained for 

airplanes with a maximum operating 

altitude of 25,000 feet or less. 

We received five comments on this 

issue. Cessna, Diamond, and GAMA 

stated that the 60-minute battery 

capacity should not be required. They 

suggested a requirement to demonstrate 

descent and landing plus 10 minutes. 

Cirrus recommended a second energy 

source instead of a 60-minute battery. 

EASA suggested including the time to 

recognize the failure and take load 

shedding action, which was 

inadvertently omitted in the NPRM. 

The FAA disagrees with the Cessna, 

Diamond, and GAMA’s comments. 

While jets often have speed brakes and 

a high dive speed, the rule requires 

descent and landing. Jets also typically 

have high stall speeds, which may limit 

the number of airports where they can 

safely land, and off-airport landing 

capability is minimal. There are also 

piston-powered airplanes that operate 

above 25,000 feet with turbocharging, 

which do not have the dive speed and 

speed brakes often installed in jets. All 

of these airplanes can operate in IMC, 

which can delay the landing. Thus, the 

60-minute battery capacity is valid for 

higher performance aircraft that operate 

above 25,000 feet. 

The FAA also disagrees with Cirrus 

that a separate power source is superior 

to a 60-minute battery. Single- or dualpower sources are not causes for 

concern because the intent of 

§ 23.1353(h) is to assume the loss of all 

generated power. 

There was not a proposal in the 

NPRM to revise § 23.1431, electronic 

equipment, but editorial changes have 

become necessary since there were 

paragraph designation changes in 

§ 23.1309. 

We proposed changing requirements 

in § 23.1443 for minimum mass flow of 

supplemental oxygen. The FAA has 

addressed oxygen systems for airplanes 

operating above 41,000 feet using 

special conditions derived from part 25. 

A large number of new jets and highperformance airplanes applying for part 

23 certification operate at higher 

altitudes than previously envisioned for 

part 23 airplanes. Proposed revisions 

would establish requirements for those 

oxygen systems. These proposed 

revisions would also eliminate the need 

for oxygen system special conditions for 

airplanes with maximum operating 

altitudes above 41,000 feet. 

Cessna and EASA stated that the 

proposed rule conflicted with another 

rule for crew oxygen equipment since a 

continuous oxygen system is 

unacceptable for the crew at that 

altitude. The FAA agrees and has 

modified § 23.1443(a) to apply 

continuous flow oxygen systems only to 

passengers for operations above 41,000 

feet as required by § 23.1441(d). 

J. Placards, Operating Limitations, and 

Information 

Proposed revisions to airspeed 

limitations in § 23.1505(c) would 

include jet-specific V-speeds. This 

proposal would base airspeed limits on 

a combination of analytical (VD/MD) and 

demonstrated (VDF/MDF) dive speeds for 

jets. 

The FAA received one comment from 

EASA. EASA stated that it applies a 

special condition for high-speed 

characteristics not included in our 

proposal. Again, EASA’s comment 

suggests performance-based standards. 

Amending part 23 to a performancebased standard is a substantially larger 

initiative than this rulemaking effort. 

The FAA also proposed amendments 

that were clarifying in nature so 

applicants would understand that they 

may need additional equipment for their 

airplane(s) to conduct part 135 

operations. Part 23 is a minimumperformance standard, and it may not 

include all the required equipment for 

operations under part 135. Proposed 

revisions to § 23.1525 would include 

parts 91 and 135 as potential kinds of 

authorized operation. 

The FAA received comments from 

Transport Canada, Embraer, Cirrus, and 

Diamond. All four commenters stated 

that the operating rules should not be 

referenced in part 23. There was 

concern the proposed revisions could be 

misinterpreted and increase the 

certification burden to manufacturers. 

We do not intend to add any burden to 

manufacturers. We simply wanted to 

remind them that in many cases, part 

135 operations require additional 

equipment not typically installed as 

standard equipment in part 23 

airplanes. However, in light of those 

comments, this proposal is withdrawn. 

The FAA proposed revising 

§§ 23.1583(c)(3), 23.1583(c)(4), and 

23.1583(c)(5), operating limitations; 

§ 23.1585(f), operating procedures; and 

§ 23.1587(d) performance information 

by applying most commuter category 

performance requirements to jets 

weighing over 6,000 pounds. The 

proposed AFM requirements would 

maintain consistency with the 

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performance requirements proposed in 

Subpart B. These requirements include 

the single-engine climb performance 

increase for turboprops. 

The FAA received three comments, 

one from EASA, Diamond, and 

Transport Canada. EASA states that it 

requires a special condition for landing 

distance factors not included in our 

proposal. This comment is outside the 

scope of this rulemaking effort. 

Diamond questioned the distinction 

between turbines and high-performance 

piston airplanes. The FAA agrees 

conceptually with these comments, but 

they are also beyond the scope of this 

rulemaking effort. Transport Canada 

stated that part 23 jets should include 

data for wet and contaminated runways. 

The upcoming part 23 regulatory review 

for future rulemaking will consider 

performance data. 

K. Test Procedure and Appendices 

The FAA proposed changing 

Appendix F, which is the test procedure 

for the requirement in § 23.856. GE 

asked if the test procedure was new. 

The test procedure is not new; 

Appendix F modifications made new 

part 23, Appendix F, part II, identical to 

part 25, Appendix F, part VI. GAMA 

questioned the use of a brand name in 

the discussion of Appendix F, Figure 

F1. In response, we reaffirm the use of 

the brand name as adopted from part 25, 

Appendix F. Again, our efforts toward 

standardization should be maintained 

wherever appropriate in our 

requirements. Appendix F is adopted as 

proposed. 

III. Regulatory Analyses 

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 

FAA has determined that there is no 

new requirement for information 

collection associated with this final 

rule. 

International Compatibility 

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 no differences with 

these regulations. 

Regulatory Evaluation, Regulatory 

Flexibility Determination, International 

Trade Impact Assessment, and 

Unfunded Mandates Assessment 

Changes to Federal regulations must 

undergo several economic analyses. 

First, Executive Order 12866 directs 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 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 

final rule. Readers seeking greater detail 

should read the full regulatory 

evaluation, a copy of which we have 

placed in the docket for this rulemaking. 

In conducting these analyses, the FAA 

has determined that this final rule: (1) 

Has benefits that justify its costs, (2) is 

not an economically ‘‘significant 

regulatory action’’ as defined in section 

3(f) of Executive Order 12866, (3) is 

‘‘significant’’ as defined in DOT’s 

Regulatory Policies and Procedures; (4) 

will not have a significant economic 

impact on a substantial number of small 

entities; (5) will not create unnecessary 

obstacles to the foreign commerce of the 

United States; and (6) will 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. 

Total Benefits and Costs of This Rule 

The estimated cost of this final rule 

ranges from a low of $65.2 million to a 

high of $72.9 million in nominal dollars 

($22.9 million to $26.7 million at a 

seven percent present value). 

The total benefits are equal to the sum 

of the safety and efficiency benefits. The 

estimated safety benefits of avoiding 26 

accidents on newly certificated part 23 

airplanes over the 57-year analysis 

interval are estimated at about $187.1 

million in nominal dollars ($46.5 

million at a seven percent present 

value). 

The estimated efficiency benefits to 

streamline the part 23 certification 

process are valued at about $965 

thousand, in nominal dollars, for five 

special conditions per aircraft 

certification, to about $1.5 million, in 

nominal dollars, for eight special 

conditions per aircraft certification. The 

total benefits range from a low of about 

$188.1 million to high of about $188.6 

million in nominal dollars. The 

following table shows these results. 

Who is Potentially Affected by This 

Rule 

This rulemaking will affect U.S. 

manufacturers and operators of part 23 

turbojets, turboprops, and reciprocating 

engine airplanes. 

Assumptions 

This final rule makes the following 

assumptions: 

• The base year is 2010; 


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• The average life of a U.S.-operated 

part 23 airplane is 32 years; 

• The average part 23 airplane 

production life cycle is 25 years; 

• The analysis period extends for 57 

years (32 + 25); and 

• The value of a fatality avoided is 

$6.0 million. 

Benefits of This Rule 

The FAA estimates the final rule will 

avoid 26 accidents over the 32-year 

operating life of 29,725 newly 

certificated and delivered part 23 

airplanes. The resulting benefits include 

standardizing and streamlining the 

certification process, averted fatalities 

and injuries, loss of airplanes, 

investigation cost, and collateral 

damages for the accidents. 

The safety benefits for averting the 26 

accidents are about $187.1 million in 

nominal dollars ($46.5 million at a 

seven percent present value). Other 

benefits of this final rule include FAA 

and industry paperwork and 

certification time saved by 

standardizing and streamlining the 

certification of part 23 airplanes. These 

efficiency benefits for standardizing and 

streamlining the certification process 

range from a low estimate of about $965 

thousand to a high estimate of $1.5 

million in nominal dollars. 

The total benefits are equal to the sum 

of the safety and efficiency benefits and 

range from a low of about $188.1 

million to high of about $188.6 million 

in nominal dollars. 

Costs of This Rule 

Estimated nominal dollar unit costs 

per part 23 airplane could be as high as: 

$1,009 for reciprocating engine 

airplanes, $6,105 for turboprops, and 

$8,053 for turbojets. Total incremental 

costs equal the nominal dollar unit costs 

multiplied by the number of newly 

certificated airplanes produced and 

delivered over the analysis interval. The 

estimated cost of this final rule ranges 

from a low of $65.2 million to high of 

$72.9 million in nominal dollars ($22.9 

million to $26.7 at a seven percent 

present value). 

Alternatives Considered 

• Alternative 1—The FAA would 

continue to issue special exemptions, 

exceptions and equivalent levels of 

safety to certificate part 23 airplanes. As 

that would perpetuate ‘‘rulemaking by 

exemption,’’ we choose not to continue 

with the status quo; and 

• Alternative 2—The FAA would 

continue to enforce the current 

regulations that affect single-engine 

climb performance and power loss. The 

FAA rejected this alternative because 

the accident rate for part 23 airplanes 

identified a safety issue that had to be 

addressed. 

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. 

However, if an agency determines that 

a rule is not expected to have a 

significant economic impact on a 

substantial number of small entities, 

Section 605(b) of the RFA provides that 

the head of the agency may so certify 

and a regulatory flexibility analysis is 

not required. The certification must 

include a statement providing the 

factual basis for this determination, and 

the reasoning should be clear. 

The FAA has determined that this 

final rule will not have a significant 

impact on a substantial number of small 

entities. The purpose of this analysis is 

to provide the reasoning underlying the 

FAA’s determination. 

The FAA made the same 

determination that this proposal would 

not have a significant impact on a 

substantial number of small entities in 

the notice of proposed rulemaking 

(NPRM). The only comment regarding 

small entities for the NPRM was Sino 

Swearingen, who requested we note that 

it is now Emivest Aerospace, which is 

foreign owned. 

First, we will discuss the reasons why 

the FAA is considering this action. We 

will follow with a discussion of the 

objective of, and legal basis for, the rule. 

Next we explain there are no relevant 

federal rules which may overlap, 

duplicate, or conflict with the final rule. 

Lastly, we will describe and provide an 

estimate of the number of small entities 

affected by the final rule and why the 

FAA believes this final rule will not 

result in a significant economic impact 

on a substantial number of small 

entities. 

We now discuss the reasons why the 

FAA is considering this action. 

The FAA proposed this action to 

amend safety and applicability 

standards for part 23 turbojets to reflect 

the current needs of the industry, 

accommodate future trends, address 

emerging technologies, and provide for 

future aircraft operations. This final rule 

primarily standardizes and streamlines 

the certification of part 23 turbojets. The 

changes to part 23 are necessary to 

eliminate the current workload of 

exemptions, special conditions, and 

equivalent levels of safety necessary to 

certificate part 23 turbojets. These part 

23 changes will also clarify areas of 

frequent non-standardization and 

misinterpretation and provide 

appropriate safety and applicability 

standards that reflect the current state of 

the industry, emerging technologies and 

new types of operations for all part 23 

airplanes, including turbojets, 

turboprops, and reciprocating engine 

airplanes. 

The FAA currently issues type 

certificates (TCs) for part 23 turbojets 

using extensive special conditions. 

Issuance of TCs has not been significant 

until now because there were few part 

23 turbojet certification programs. 

However, in the past seven years, the 

number of new part 23 turbojet 

certification programs has increased by 

more than 100 percent when compared 

to over the past three decades. 

The need to incorporate these special 

conditions into part 23 stems from both 

the existing number of new turbojet 

certification programs and the expected 

number of future turbojet programs. 

Codifying these special conditions will 

allow manufacturers to know the 

requirements during the design phase 

instead of designing the turbojet and 

then having to apply for special 

conditions that may ultimately require a 

redesign. Codifying will also reduce the 

manufacturers and FAA’s paper process 

required to type certificate an airplane 

and reduces the potential for program 

delays. These final rule changes will 

also clarify areas of frequent nonstandardization and misinterpretation, 

particularly for electronic equipment 

and system certification on all newly 

certificated part 23 airplanes. 

The revisions include general 

definitions, error corrections, and 

specific requirements for performance 

and handling characteristics to ensure 

safe operation of part 23 airplanes. The 

revisions will apply to all future new 

part 23 turbojets, turboprops, and 

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2 13 CFR 121.201, Size Standards Used to Define 

Small Business Concerns, Sector 48–49 

Transportation, Subsector 481 Air Transportation. 

3http://www.sba.gov/advo/research/us05_n6.pdf. 

reciprocating engine airplane 

certifications. 

We now discuss the legal basis for, 

and objective of, the rule. Next, we 

discuss if there are relevant federal rules 

that may overlap, duplicate, or conflict 

with the rule. 

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 aircraft in air commerce by 

prescribing minimum standards 

required in the interest of safety for the 

design and performance of aircraft. This 

regulation is within the scope of that 

authority because it prescribes new 

safety standards for the design of part 23 

normal, utility, acrobatic, and commuter 

category airplanes. 

Accordingly, this final rule will 

amend Title 14, the Code of Federal 

Regulations to address deficiencies in 

current regulations regarding the 

certification of part 23 light turbojets, 

turboprops and reciprocating engine 

airplanes. The final rule will also clarify 

areas of frequent non-standardization 

and misinterpretation and codify 

certification requirements that currently 

exist in special conditions. 

The rule will not overlap, duplicate, 

or conflict with existing federal rules. 

We now discuss our methodology to 

determine the number of small entities 

for which the rule will apply. 

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.2

There are nine U.S.-owned aircraft 

manufacturers who deliver part 23 

airplanes in the 1998–2009 analysis 

interval. These manufacturers are 

American Champion, Cessna, Cirrus, 

Hawker Beechcraft, Liberty, Maule, 

Mooney, Piper, and Quest. 

Using information provided by the 

World Aviation Directory, Internet 

filings and industry contacts, 

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 and Cirrus and 

Liberty are foreign owned. We found no 

source of employment or revenue data 

for American Champion. For the 

remaining businesses, we obtained 

company revenue and employment from 

the above sources. 

The base year for the final rule is 

2010. Although the FAA forecasts traffic 

and air carrier fleets, we cannot 

determine the number of new entrants, 

nor who will be in the part 23 aircraft 

manufacturing business in the future. 

Therefore we use current U.S. part 23 

aircraft manufacturers’ revenue and 

employment in order to determine the 

number of operators this final rule will 

affect. 

The methodology discussed above 

resulted in the following list of four U.S. 

part 23 aircraft manufactures, with less 

than 1,500 employees. 

From the list of small entity U.S. 

airplane manufacturers above, there are 

no manufacturers currently producing 

part 23 turbojets; only Piper and Quest 

produce turboprops. The remaining 

small entity U.S. aircraft manufacturers 

produce part 23 reciprocating engine 

airplanes. 

The U.S. Census Bureau data on the 

Small Business Administration’s Web 

site shows an estimate of the total 

number of small entities who could be 

affected if they purchase newly 

certificated part 23 airplanes. The U.S. 

Census Bureau data lists 39,754 small 

entities in the Non-scheduled Air 

Transportation Industry that employ 

less than 500 employees. Many of these 

non-scheduled businesses are subject to 

part 25. Other small businesses may 

own aircraft and not be included in the 

U.S. Census Bureau Non-scheduled Air 

Transportation Industry category.3

Therefore, we will use the list of small 

entities from Table RF1 instead of the 

U.S. Census Bureau data for our Final 

Regulatory Flexibility Act (FRFA) 

analysis. 

We will now develop the estimate of 

the effect of this final rule on the total 

number of small entities that 

manufacture part 23 airplanes. 

First, we discuss our methodology to 

estimate the costs of the final rule to the 

small entity part 23 airplane 

manufacturers and operators. Next, we 

will discuss why the FAA believes the 

final rule will not result in a significant 

economic impact to part 23 airplane 

manufacturers and operators. 

In 2003, we published a notice (68 FR 

5488) creating the part 125/135 Aviation 

Rulemaking Committee (ARC). The FAA 

and the part 23 industry have worked 

together to develop common part 23 

airplane certification requirements for 

this rulemaking. We contacted the part 

23 aircraft manufacturers, the ARC, and 

GAMA (an industry association for part 

23 aircraft manufacturers) for specific 

cost estimates for each section change 

for the final rule. Not every party we 

contacted responded to our request for 

costs. Many of the ARC members, from 

the domestic and international 

manufacturing community, collaborated 

and filed a joint cost estimate for the 

proposed rule. 

We are basing our cost estimates for 

this final rule from data provided by the 

domestic part 23 U.S. aircraft 

manufacturers, ARC members, and 

GAMA. They informed us that the final 


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rule will add costs for fire extinguishing 

systems, climb, take-off warning 

systems, ventilation systems, system 

designs, and batteries. Industry 

informed us that this proposal will save 

the manufacturers design time for the 

certification of cockpit controls. 

Industry has also informed us that every 

other section of this final rule is either 

clarifying, error correcting, or will only 

add minimal to no costs. 

The final rule adds certification 

requirements for the following part 23 

airplane categories: 

1. Turbojets; 

2. Turbojets with a MTOW less than 

6,000 pounds; 

3. Turboprops; 

4. Turboprops with a MTOW less than 

6,000 pounds; 

5. Reciprocating engine airplanes; and 

6. Reciprocating engine airplanes with 

a MTOW greater than 6,000 pounds. 

In some cases the final rule will only 

affect part 23 airplanes operated in 

revenue service. Any part 23 airplane 

could be used as a business airplane to 

haul passengers and cargo in 

commercial service. We estimated the 

business versus the personal use of a 

part 23 airplane by analyzing the 

number of all U.S.-operated airplanes 

from Table 3.1 of the 2008 General 

Aviation and Part 135 Activity Survey. 

Table 3.1 of that survey shows the 

breakout of the 2008 General Aviation 

fleet by business, corporate, 

instructional, aerial applications, aerial 

observations, aerial other, external load, 

other work, sight see, air medical, other, 

part 135 Air Taxi, Air Tours, and Air 

Medical airplane usage. For the purpose 

of estimating the cost of this proposal, 

we assume all-business part 23 airplane 

operators from Table 3.1 of the 2008 

General Aviation and Part 135 Activity 

Survey will operate in commuter 

service. 

Table RF2 shows these results: 

Table RF3 shows the final rule 

sections that add (or subtract) 

incremental costs by increasing design 

or flight testing times, adding weight, 

adding batteries, or reducing payload: 

We estimated part 23 airplane fixed 

manufacturer (added certification plus 

flight test hours) and operator-variable 

flight operation (added weight, batteries, 

or a reduction in payload) costs and 

applied our estimated costs to the 

expected fleet delivered in compliance 

with this final rule. The total cost of this 

final rule is the sum of the fixed 

certification cost plus the variable flight 

operation cost multiplied by the 

expected newly certificated part 23 fleet 

delivered over the analysis interval. 

The total fixed certification 

compliance cost equals the industryprovided incremental hours or dollar 

costs multiplied by the expected 

number of new certifications for part 23 

turbojets, turboprops, and reciprocating 

engine airplanes. 

The total variable flight operation 

compliance cost equals the industryprovided incremental weight, payload 

reduction, or dollar costs multiplied by 

the expected number of newly 

certificated part 23 turbojets, 

turboprops, and reciprocating engine 

airplanes delivered. In the regulatory 

analysis, we estimated a low case and a 

high case cost range for the fixed 

operation compliance costs. The range 

was based on the 10% loss in payload 

capacity noted in Table RF3. 

In the low case, we estimated no loss 

in capacity because our analysis showed 

that part 23 airplanes operate well 

below the airplane’s payload capacity. 

In the high case, we estimated a cost to 

operators for the 10% loss in payload 

capacity. We will use the high-variable, 

flight operation cost scenario for this 

FRFA analysis. 

We estimated the nominal dollar unit 

costs for all part 23 airplanes by 

summing the fixed certification costs 


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with the variable flight operations 

compliance costs by part 23 turbojets, 

turboprops, and reciprocating engine 

airplanes. Next, we divided these sums 

by the number of newly certificated 

delivered part 23 turbojets, turboprops, 

and reciprocating engine airplanes. Our 

calculations yielded that unit costs 

could be as high as $1,009 for newly 

certificated reciprocating engine 

airplanes and $6,105 for turboprop 

airplanes. 

We then took the product of the 

estimated unit airplane cost with the 

average annual number of part 23 

turbojets, turboprops, and reciprocating 

engine airplanes that each of the four 

small business part 23 manufacturers 

(from Table RF1) delivered from 1998 to 

2009. This product determined the 

annual impact of the final rule to each 

small business part 23 manufacturer. 

Lastly, we divided each small part 23 

airplane manufacturer’s annual revenue 

by the incremental costs. 

Table RF4 shows these results: 

We do not believe that these final rule 

costs will be a significant impact to 

small entity operators because, even for 

the high-cost case, the compliance costs 

of this proposal to operators would only 

be less than one percent of annual 

revenue for each of the small business 

part 23 manufacturers. Again, the only 

comment regarding small entities for the 

NPRM was the noted comment from 

Sino Swearingen. 

Therefore, as the FAA Administrator, 

I certify that this final rule will not have 

a significant economic impact on a 

substantial number of small entities. 

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 final rule and determined 

that the standards are necessary for 

aviation safety and will not create 

unnecessary obstacles to the foreign 

commerce of the United States. 

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 inflationadjusted value of $140.8 million in lieu 

of $100 million. This final rule does not 

contain such a mandate; therefore, the 

requirements of Title II of the Act do not 

apply. 

Executive Order 13132, Federalism 

The FAA has analyzed this final rule 

under the principles and criteria of 

Executive Order 13132, Federalism. We 

determined that this action will 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; therefore, it does 

not have federalism implications. 

Regulations Affecting Intrastate 

Aviation in Alaska 

Section 1205 of the FAA 

Reauthorization Act of 1996 (110 Stat. 

3213) requires the FAA, when 

modifying its 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. In 

the NPRM, we requested comments on 

whether the proposed rule should apply 

differently to intrastate operations in 

Alaska. We did not receive any 

comments. We have determined, based 

on the administrative record of this 

rulemaking, that there is no need to 

make any regulatory distinctions 

applicable to intrastate aviation in 

Alaska. 

Environmental Analysis 

FAA Order 1050.1E 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 312(f) and involves no 

extraordinary circumstances. 

Regulations That Significantly Affect 

Energy Supply, Distribution, or Use 

The FAA analyzed this final rule 

under Executive Order 13211, Actions 

Concerning Regulations that 

Significantly Affect Energy Supply, 

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

have determined that it is not a 

‘‘significant energy action’’ under the 

executive order because it is not a 

‘‘significant regulatory action,’’ and it is 

not likely to have a significant adverse 

effect on the supply, distribution, or use 

of energy. 

Availability of Rulemaking Documents 

You can get an electronic copy of 

rulemaking documents using 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.

gpoaccess.gov/fr/index.html. 

You can also get a copy by sending a 

request to the Federal Aviation 

Administration, Office of Rulemaking, 


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ARM–1, 800 Independence Avenue 

SW., Washington, DC 20591, or by 

calling (202) 267–9680. Make sure to 

identify the notice, amendment, or 

docket number of this rulemaking. 

Anyone is able to search the 

electronic form of all comments 

received into any of our dockets by the 

name of the individual submitting the 

comment (or by signing the comment, if 

submitted on behalf of an association, 

business, labor union, etc.). You may 

review DOT’s complete Privacy Act 

statement in the Federal Register 

published on April 11, 2000 (Volume 

65, Number 70; Pages 19477–78) or you 

may visit http://DocketsInfo.dot.gov. 

Small Business Regulatory Enforcement 

Fairness Act 

The Small Business Regulatory 

Enforcement Fairness Act (SBREFA) of 

1996 requires FAA to comply with 

small entity requests for information or 

advice about compliance with statutes 

and regulations within its jurisdiction. If 

you are a small entity and you have a 

question regarding this document, you 

may contact your local FAA official, or 

the person listed under the FOR FURTHER

INFORMATION CONTACT heading at the 

beginning of the preamble. You can find 

out more about SBREFA on the Internet 

at http://www.faa.gov/regulations_

policies/rulemaking/sbre_act/. 

List of Subjects in 14 CFR Part 23 

Aviation safety, Signs, Symbols, 

Aircraft. 

The Amendments 

In consideration of the foregoing, the 

Federal Aviation Administration 

amends Chapter I of Title 14, Code of 

Federal Regulations, as follows: 

PART 23—AIRWORTHINESS 

STANDARDS; NORMAL, UTILITY, 

ACROBATIC, AND COMMUTER 

CATEGORY AIRPLANES 

■ 1. The authority citation for part 23 

continues to read as follows: 

Authority: 49 U.S.C. 106(G), 40113, 44701– 

44702, 44704. 

■ 2. Amend § 23.3 by revising the first 

sentence in paragraph (d) to read as 

follows: 

§ 23.3 Airplane categories. 

* * * * * 

(d) The commuter category is limited 

to multiengine airplanes that have a 

seating configuration, excluding pilot 

seats, of 19 or less, and a maximum 

certificated takeoff weight of 19,000 

pounds or less. * * * 

* * * * * 

■ 3. Amend § 23.45 by revising the 

introductory text of paragraph (h) to 

read as follows: 

§ 23.45 General. 

* * * * * 

(h) For multiengine jets weighing over 

6,000 pounds in the normal, utility, and 

acrobatic category and commuter 

category airplanes, the following also 

apply: 

* * * * * 

■ 4. Amend § 23.49 by revising the 

section heading and the introductory 

text of paragraphs (a) and (c) to read as 

follows: 

§ 23.49 Stalling speed. 

(a) VSO (maximum landing flap 

configuration) and VS1 are the stalling 

speeds or the minimum steady flight 

speeds, in knots (CAS), at which the 

airplane is controllable with— 

* * * * * 

(c) Except as provided in paragraph 

(d) of this section, VSO at maximum 

weight may not exceed 61 knots for— 

* * * * * 

■ 5. Amend § 23.51 by revising 

paragraph (b)(1) introductory text and 

paragraph (c) introductory text to read 

as follows: 

§ 23.51 Takeoff speeds. 

* * * * * 

(b) * * * 

(1) For multiengine airplanes, the 

highest of— 

* * * * * 

(c) For normal, utility, and acrobatic 

category multiengine jets of more than 

6,000 pounds maximum weight and 

commuter category airplanes, the 

following apply: 

* * * * * 

■ 6. Amend § 23.53 by revising 

paragraph (c) to read as follows: 

§ 23.53 Takeoff performance. 

* * * * * 

(c) For normal, utility, and acrobatic 

category multiengine jets of more than 

6,000 pounds maximum weight and 

commuter category airplanes, takeoff 

performance, as required by §§ 23.55 

through 23.59, must be determined with 

the operating engine(s) within approved 

operating limitations. 

■ 7. Amend § 23.55 by revising the 

introductory text to read as follows: 

§ 23.55 Accelerate-stop distance. 

For normal, utility, and acrobatic 

category multiengine jets of more than 

6,000 pounds maximum weight and 

commuter category airplanes, the 

accelerate-stop distance must be 

determined as follows: 

* * * * * 

■ 8. Amend § 23.57 by revising the 

introductory text to read as follows: 

§ 23.57 Takeoff path. 

For normal, utility, and acrobatic 

category multiengine jets of more than 

6,000 pounds maximum weight and 

commuter category airplanes, the takeoff 

path is as follows: 

* * * * * 

■ 9. Amend § 23.59 by revising the 

introductory text to read as follows: 

§ 23.59 Takeoff distance and takeoff run. 

For normal, utility, and acrobatic 

category multiengine jets of more than 

6,000 pounds maximum weight and 

commuter category airplanes, the takeoff 

distance and, at the option of the 

applicant, the takeoff run, must be 

determined. 

* * * * * 

■ 10. Amend § 23.61 by revising the 

introductory text to read as follows: 

§ 23.61 Takeoff flight path. 

For normal, utility, and acrobatic 

category multiengine jets of more than 

6,000 pounds maximum weight and 

commuter category airplanes, the takeoff 

flight path must be determined as 

follows: 

* * * * * 

■ 11. Amend § 23.63 by revising the 

introductory text of paragraphs (c) and 

(d) to read as follows: 

§ 23.63 Climb: General. 

* * * * * 

(c) For reciprocating engine-powered 

airplanes of more than 6,000 pounds 

maximum weight, single-engine 

turbines, and multiengine turbine 

airplanes of 6,000 pounds or less 

maximum weight in the normal, utility, 

and acrobatic category, compliance 

must be shown at weights as a function 

of airport altitude and ambient 

temperature, within the operational 

limits established for takeoff and 

landing, respectively, with— 

* * * * * 

(d) For multiengine turbine airplanes 

over 6,000 pounds maximum weight in 

the normal, utility, and acrobatic 

category and commuter category 

airplanes, compliance must be shown at 

weights as a function of airport altitude 

and ambient temperature within the 

operational limits established for takeoff 

and landing, respectively, with— 

* * * * * 

■ 12. Amend § 23.65 by revising 

paragraph (b) to read as follows: 

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§ 23.65 Climb: All engines operating. 

* * * * * 

(b) Each normal, utility, and acrobatic 

category reciprocating engine-powered 

airplane of more than 6,000 pounds 

maximum weight, single-engine turbine, 

and multiengine turbine airplanes of 

6,000 pounds or less maximum weight 

in the normal, utility, and acrobatic 

category must have a steady gradient of 

climb after takeoff of at least 4 percent 

with 

* * * * * 

■ 13. Amend § 23.67 by revising 

paragraph (b) introductory text and 

(b)(1) introductory text, redesignating 

paragraph (c) as paragraph (d), revising 

newly redesignated paragraph (d) 

introductory text, and adding new 

paragraph (c) to read as follows: 

§ 23.67 Climb: One-engine inoperative. 

* * * * * 

(b) For normal, utility, and acrobatic 

category reciprocating engine-powered 

airplanes of more than 6,000 pounds 

maximum weight, and turbopropellerpowered airplanes in the normal, utility, 

and acrobatic category— 

(1) The steady gradient of climb at an 

altitude of 400 feet above the takeoff 

must be no less than 1 percent with 

the— 

* * * * * 

(c) For normal, utility, and acrobatic 

category jets of 6,000 pounds or less 

maximum weight— 

(1) The steady gradient of climb at an 

altitude of 400 feet above the takeoff 

must be no less than 1.2 percent with 

the— 

(i) Critical engine inoperative; 

(ii) Remaining engine(s) at takeoff 

power; 

(iii) Landing gear retracted; 

(iv) Wing flaps in the takeoff 

position(s); and 

(v) Climb speed equal to that achieved 

at 50 feet in the demonstration of 

§ 23.53. 

(2) The steady gradient of climb may 

not be less than 0.75 percent at an 

altitude of 1,500 feet above the takeoff 

surface, or landing surface, as 

appropriate, with the— 

(i) Critical engine inoperative; 

(ii) Remaining engine(s) at not more 

than maximum continuous power; 

(iii) Landing gear retracted; 

(iv) Wing flaps retracted; and 

(v) Climb speed not less than 1.2 VS1. 

(d) For jets over 6,000 pounds 

maximum weight in the normal, utility 

and acrobatic category and commuter 

category airplanes, the following apply: 

* * * * * 

■ 14. Revise § 23.73 to read as follows: 

§ 23.73 Reference landing approach 

speed. 

(a) For normal, utility, and acrobatic 

category reciprocating engine-powered 

airplanes of 6,000 pounds or less 

maximum weight, the reference landing 

approach speed, VREF, may not be less 

than the greater of VMC, determined in 

§ 23.149(b) with the wing flaps in the 

most extended takeoff position, and 1.3 

VS1. 

(b) For normal, utility, and acrobatic 

category turbine powered airplanes of 

6,000 pounds or less maximum weight, 

turboprops of more than 6,000 pounds 

maximum weight, and reciprocating 

engine-powered airplanes of more than 

6,000 pounds maximum weight, the 

reference landing approach speed, VREF, 

may not be less than the greater of VMC, 

determined in § 23.149(c), and 1.3 VS1. 

(c) For normal, utility, and acrobatic 

category jets of more than 6,000 pounds 

maximum weight and commuter 

category airplanes, the reference landing 

approach speed, VREF, may not be less 

than the greater of 1.05 VMC, determined 

in § 23.149(c), and 1.3 VS1. 

■ 15. Amend § 23.77 by revising the 

introductory text of paragraphs (b) and 

(c) to read as follows: 

§ 23.77 Balked landing. 

* * * * * 

(b) Each normal, utility, and acrobatic 

category reciprocating engine-powered 

and single engine turbine powered 

airplane of more than 6,000 pounds 

maximum weight, and multiengine 

turbine engine-powered airplane of 

6,000 pounds or less maximum weight 

in the normal, utility, and acrobatic 

category must be able to maintain a 

steady gradient of climb of at least 2.5 

percent with— 

* * * * * 

(c) Each normal, utility, and acrobatic 

multiengine turbine powered airplane 

over 6,000 pounds maximum weight 

and each commuter category airplane 

must be able to maintain a steady 

gradient of climb of at least 3.2 percent 

with— 

* * * * * 

■ 16. Amend § 23.177 by revising 

paragraphs (a), (b), and (d) to read as 

follows: 

§ 23.177 Static directional and lateral 

stability. 

(a)(1) The static directional stability, 

as shown by the tendency to recover 

from a wings level sideslip with the 

rudder free, must be positive for any 

landing gear and flap position 

appropriate to the takeoff, climb, cruise, 

approach, and landing configurations. 

This must be shown with symmetrical 

power up to maximum continuous 

power, and at speeds from 1.2 VS1 up to 

VFE, VLE, VNO, VFC/MFC, whichever is 

appropriate. 

(2) The angle of sideslip for these tests 

must be appropriate to the type of 

airplane. The rudder pedal force must 

not reverse at larger angles of sideslip, 

up to that at which full rudder is used 

or a control force limit in § 23.143 is 

reached, whichever occurs first, and at 

speeds from 1.2 VS1 to VO. 

(b)(1) The static lateral stability, as 

shown by the tendency to raise the low 

wing in a sideslip with the aileron 

controls free, may not be negative for 

any landing gear and flap position 

appropriate to the takeoff, climb, cruise, 

approach, and landing configurations. 

This must be shown with symmetrical 

power from idle up to 75 percent of 

maximum continuous power at speeds 

from 1.2 VS1 in the takeoff 

configuration(s) and at speeds from 1.3 

VS1 in other configurations, up to the 

maximum allowable airspeed for the 

configuration being investigated (VFE, 

VLE, VNO, VFC/MFC, whichever is 

appropriate) in the takeoff, climb, 

cruise, descent, and approach 

configurations. For the landing 

configuration, the power must be that 

necessary to maintain a 3-degree angle 

of descent in coordinated flight. 

(2) The static lateral stability may not 

be negative at 1.2 VS1 in the takeoff 

configuration, or at 1.3 VS1 in other 

configurations. 

(3) The angel of sideslip for these tests 

must be appropriate to the type of 

airplane, but in no case may the 

constant heading sideslip angle be less 

than that obtainable with a 10 degree 

bank or, if less, the maximum bank 

angle obtainable with full rudder 

deflection or 150 pound rudder force. 

* * * * * 

(d)(1) In straight, steady slips at 1.2 

VS1 for any landing gear and flap 

position appropriate to the takeoff, 

climb, cruise, approach, and landing 

configurations, and for any symmetrical 

power conditions up to 50 percent of 

maximum continuous power, the 

aileron and rudder control movements 

and forces must increase steadily, but 

not necessarily in constant proportion, 

as the angle of sideslip is increased up 

to the maximum appropriate to the type 

of airplane. 

(2) At larger slip angles, up to the 

angle at which the full rudder or aileron 

control is used or a control force limit 

contained in § 23.143 is reached, the 

aileron and rudder control movements 

and forces may not reverse as the angle 

of sideslip is increased. 

(3) Rapid entry into, and recovery 

from, a maximum sideslip considered 

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appropriate for the airplane may not 

result in uncontrollable flight 

characteristics. 

■ 17. Amend § 23.181 by revising 

paragraph (b) to read as follows: 

§ 23.181 Dynamic stability. 

* * * * * 

(b) Any combined lateral-directional 

oscillations (Dutch roll) occurring 

between the stalling speed and the 

maximum allowable speed (VFE, VLE, 

VN0, VFC/MFC) appropriate to the 

configuration of the airplane with the 

primary controls in both free and fixed 

position, must be damped to 1/10 

amplitude in: 

(1) Seven (7) cycles below 18,000 feet 

and 

(2) Thirteen (13) cycles from 18,000 

feet to the certified maximum altitude. 

* * * * * 

■ 18. Amend § 23.201 by revising 

paragraph (d), by revising and 

redesignating current paragraph (e) as 

paragraph (f), and by adding a new 

paragraph (e) to read as follows: 

§ 23.201 Wings level stall. 

* * * * * 

(d) During the entry into and the 

recovery from the maneuver, it must be 

possible to prevent more than 15 

degrees of roll or yaw by the normal use 

of controls except as provided for in 

paragraph (e) of this section. 

(e) For airplanes approved with a 

maximum operating altitude at or above 

25,000 feet during the entry into and the 

recovery from stalls performed at or 

above 25,000 feet, it must be possible to 

prevent more than 25 degrees of roll or 

yaw by the normal use of controls. 

(f) Compliance with the requirements 

of this section must be shown under the 

following conditions: 

(1) Wing flaps: Retracted, fully 

extended, and each intermediate normal 

operating position, as appropriate for 

the phase of flight. 

(2) Landing gear: Retracted and 

extended as appropriate for the altitude. 

(3) Cowl flaps: Appropriate to 

configuration. 

(4) Spoilers/speedbrakes: Retracted 

and extended unless they have no 

measureable effect at low speeds. 

(5) Power: 

(i) Power/Thrust off; and 

(ii) For reciprocating engine powered 

airplanes: 75 percent of maximum 

continuous power. However, if the 

power-to-weight ratio at 75 percent of 

maximum continuous power results in 

nose-high attitudes exceeding 30 

degrees, the test may be carried out with 

the power required for level flight in the 

landing configuration at maximum 

landing weight and a speed of 1.4 VSO, 

except that the power may not be less 

than 50 percent of maximum 

continuous power; or 

(iii) For turbine engine powered 

airplanes: The maximum engine thrust, 

except that it need not exceed the thrust 

necessary to maintain level flight at 1.5 

VS1 (where VS1 corresponds to the 

stalling speed with flaps in the 

approach position, the landing gear 

retracted, and maximum landing 

weight). 

(6) Trim: At 1.5 VS1 or the minimum 

trim speed, whichever is higher. 

(7) Propeller: Full increase r.p.m. 

position for the power off condition. 

■ 19. Amend § 23.203 by revising 

paragraph (c) to read as follows: 

§ 23.203 Turning flight and accelerated 

turning stalls. 

* * * * * 

(c) Compliance with the requirements 

of this section must be shown under the 

following conditions: 

(1) Wings flaps: Retracted, fully 

extended, and each intermediate normal 

operating position as appropriate for the 

phase of flight. 

(2) Landing gear: Retracted and 

extended as appropriate for the altitude. 

(3) Cowl flaps: Appropriate to 

configuration. 

(4) Spoilers/speedbrakes: Retracted 

and extended unless they have no 

measureable effect at low speeds. 

(5) Power: 

(i) Power/Thrust off; and 

(ii) For reciprocating engine powered 

airplanes: 75 percent of maximum 

continuous power. However, if the 

power-to-weight ratio at 75 percent of 

maximum continuous power results in 

nose-high attitudes exceeding 30 

degrees, the test may be carried out with 

the power required for level flight in the 

landing configuration at maximum 

landing weight and a speed of 1.4 VSO, 

except that the power may not be less 

than 50 percent of maximum 

continuous power; or 

(iii) For turbine engine powered 

airplanes: The maximum engine thrust, 

except that it need not exceed the thrust 

necessary to maintain level flight at 1.5 

VS1 (where VS1 corresponds to the 

stalling speed with flaps in the 

approach position, the landing gear 

retracted, and maximum landing 

weight). 

(6) Trim: The airplane trimmed at 1.5 

VS1.

(7) Propeller: Full increase rpm 

position for the power off condition. 

■ 20. Revise § 23.251 to read as follows: 

§ 23.251 Vibration and buffeting. 

(a) There must be no vibration or 

buffeting severe enough to result in 

structural damage, and each part of the 

airplane must be free from excessive 

vibration, under any appropriate speed 

and power conditions up to VD/MD, or 

VDF/MDF for turbojets. In addition, there 

must be no buffeting in any normal 

flight condition, including configuration 

changes during cruise, severe enough to 

interfere with the satisfactory control of 

the airplane or cause excessive fatigue 

to the flight crew. Stall warning 

buffeting within these limits is 

allowable. 

(b) There must be no perceptible 

buffeting condition in the cruise 

configuration in straight flight at any 

speed up to VMO/MMO, except stall 

buffeting, which is allowable. 

(c) For airplanes with MD greater than 

M 0.6 or a maximum operating altitude 

greater than 25,000 feet, the positive 

maneuvering load factors at which the 

onset of perceptible buffeting occurs 

must be determined with the airplane in 

the cruise configuration for the ranges of 

airspeed or Mach number, weight, and 

altitude for which the airplane is to be 

certificated. The envelopes of load 

factor, speed, altitude, and weight must 

provide a sufficient range of speeds and 

load factors for normal operations. 

Probable inadvertent excursions beyond 

the boundaries of the buffet onset 

envelopes may not result in unsafe 

conditions. 

■ 21. Amend § 23.253 by revising 

paragraphs (b)(1) and (b)(2), and by 

adding new paragraphs (b)(3) and (d) to 

read as follows: 

§ 23.253 High speed characteristics. 

* * * * * 

(b) * * * 

(1) Exceptional piloting strength or 

skill; 

(2) Exceeding VD/MD, or VDF/MDF for 

turbojets, the maximum speed shown 

under § 23.251, or the structural 

limitations; and 

(3) Buffeting that would impair the 

pilot’s ability to read the instruments or 

to control the airplane for recovery. 

* * * * * 

(d) Maximum speed for stability 

characteristics, VFC/MFC. VFC/MFC may 

not be less than a speed midway 

between VMO/MMO and VDF/MDF except 

that, for altitudes where Mach number 

is the limiting factor, MFC need not 

exceed the Mach number at which 

effective speed warning occurs. 

■ 22. Section 23.255 is added to subpart 

B to read as follows: 

§ 23.255 Out of trim characteristics. 

For airplanes with an MD greater than 

M 0.6 and that incorporate a trimmable 

horizontal stabilizer, the following 

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requirements for out-of-trim 

characteristics apply: 

(a) From an initial condition with the 

airplane trimmed at cruise speeds up to 

VMO/MMO, the airplane must have 

satisfactory maneuvering stability and 

controllability with the degree of out-oftrim in both the airplane nose-up and 

nose-down directions, which results 

from the greater of the following: 

(1) A three-second movement of the 

longitudinal trim system at its normal 

rate for the particular flight condition 

with no aerodynamic load (or an 

equivalent degree of trim for airplanes 

that do not have a power-operated trim 

system), except as limited by stops in 

the trim system, including those 

required by § 23.655(b) for adjustable 

stabilizers; or 

(2) The maximum mistrim that can be 

sustained by the autopilot while 

maintaining level flight in the high 

speed cruising condition. 

(b) In the out-of-trim condition 

specified in paragraph (a) of this 

section, when the normal acceleration is 

varied from +l g to the positive and 

negative values specified in paragraph 

(c) of this section, the following apply: 

(1) The stick force versus g curve must 

have a positive slope at any speed up to 

and including VFC/MFC; and 

(2) At speeds between VFC/MFC and 

VDF/MDF, the direction of the primary 

longitudinal control force may not 

reverse. 

(c) Except as provided in paragraphs 

(d) and (e) of this section, compliance 

with the provisions of paragraph (a) of 

this section must be demonstrated in 

flight over the acceleration range as 

follows: 

(1) ¥1 g to +2.5 g; or 

(2) 0 g to 2.0 g, and extrapolating by 

an acceptable method to ¥1 g and +2.5 

g. 

(d) If the procedure set forth in 

paragraph (c)(2) of this section is used 

to demonstrate compliance and 

marginal conditions exist during flight 

test with regard to reversal of primary 

longitudinal control force, flight tests 

must be accomplished from the normal 

acceleration at which a marginal 

condition is found to exist to the 

applicable limit specified in paragraph 

(b)(1) of this section. 

(e) During flight tests required by 

paragraph (a) of this section, the limit 

maneuvering load factors, prescribed in 

§§ 23.333(b) and 23.337, need not be 

exceeded. In addition, the entry speeds 

for flight test demonstrations at normal 

acceleration values less than 1 g must be 

limited to the extent necessary to 

accomplish a recovery without 

exceeding VDF/MDF. 

(f) In the out-of-trim condition 

specified in paragraph (a) of this 

section, it must be possible from an 

overspeed condition at VDF/MDF to 

produce at least 1.5 g for recovery by 

applying not more than 125 pounds of 

longitudinal control force using either 

the primary longitudinal control alone 

or the primary longitudinal control and 

the longitudinal trim system. If the 

longitudinal trim is used to assist in 

producing the required load factor, it 

must be shown at VDF/MDF that the 

longitudinal trim can be actuated in the 

airplane nose-up direction with the 

primary surface loaded to correspond to 

the least of the following airplane noseup control forces: 

(1) The maximum control forces 

expected in service, as specified in 

§§ 23.301 and 23.397. 

(2) The control force required to 

produce 1.5 g. 

(3) The control force corresponding to 

buffeting or other phenomena of such 

intensity that it is a strong deterrent to 

further application of primary 

longitudinal control force. 

■ 23. Amend § 23.561 by adding new 

paragraph (e)(1), and adding and 

reserving paragraph (e)(2), to read as 

follows: 

§ 23.561 General. 

* * * * * 

(e) * * * 

(1) For engines mounted inside the 

fuselage, aft of the cabin, it must be 

shown by test or analysis that the engine 

and attached accessories, and the engine 

mounting structure— 

(i) Can withstand a forward acting 

static ultimate inertia load factor of 18.0 

g plus the maximum takeoff engine 

thrust; or 

(ii) The airplane structure is designed 

to preclude the engine and its attached 

accessories from entering or protruding 

into the cabin should the engine mounts 

fail. 

(2) [Reserved] 

■ 24. Amend § 23.562 by revising 

paragraphs (a) introductory text, (b) 

introductory text, and (c)(5)(ii) to read 

as follows: 

§ 23.562 Emergency landing dynamic 

conditions. 

(a) Each seat/restraint system for use 

in a normal, utility, or acrobatic 

category airplane, or in a commuter 

category jet airplane, must be designed 

to protect each occupant during an 

emergency landing when— 

* * * * * 

(b) Except for those seat/restraint 

systems that are required to meet 

paragraph (d) of this section, each seat/ 

restraint system for crew or passenger 

occupancy in a normal, utility, or 

acrobatic category airplane, or in a 

commuter category jet airplane, must 

successfully complete dynamic tests or 

be demonstrated by rational analysis 

supported by dynamic tests, in 

accordance with each of the following 

conditions. These tests must be 

conducted with an occupant simulated 

by an anthropomorphic test dummy 

(ATD) defined by 49 CFR part 572, 

subpart B, or an FAA-approved 

equivalent, with a nominal weight of 

170 pounds and seated in the normal 

upright position. 

* * * * * 

(c) * * * 

(5) * * * 

(ii) The value of HIC is defined as— 

Where— 

t1 is the initial integration time, expressed in 

seconds, t2 is the final integration time, 

expressed in seconds, and a(t) is the total 

acceleration vs. time curve for the head 

strike expressed as a multiple of g (units 

of gravity). 

* * * * * 

■ 25. Amend § 23.571 by adding a new 

paragraph (d) to read as follows: 

§ 23.571 Metallic pressurized cabin 

structures. 

* * * * * 

(d) If certification for operation above 

41,000 feet is requested, a damage 

tolerance evaluation of the fuselage 

pressure boundary per § 23.573(b) must 

be conducted. 

■ 26. Amend § 23.629 by revising 

paragraphs (b)(1), (b)(3), (b)(4), and (c) to 

read as follows: 


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§ 23.629 Flutter. 

* * * * * 

(b) * * * 

(1) Proper and adequate attempts to 

induce flutter have been made within 

the speed range up to VD/MD, or VDF/ 

MDF for jets; 

* * * * * 

(3) A proper margin of damping exists 

at VD/MD, or VDF/MDF for jets; and 

(4) As VD/MD (or VDF/MDF for jets) is 

approached, there is no large or rapid 

reduction in damping. 

(c) Any rational analysis used to 

predict freedom from flutter, control 

reversal and divergence must cover all 

speeds up to 1.2 VD/1.2 MD, limited to 

Mach 1.0 for subsonic airplanes. 

* * * * * 

■ 27. Amend § 23.703 by revising the 

introductory text and adding a new 

paragraph (c) to read as follows: 

§ 23.703 Takeoff warning system. 

For all airplanes with a maximum 

weight more than 6,000 pounds and all 

jets, unless it can be shown that a lift 

or longitudinal trim device that affects 

the takeoff performance of the airplane 

would not give an unsafe takeoff 

configuration when selected out of an 

approved takeoff position, a takeoff 

warning system must be installed and 

meet the following requirements: 

* * * * * 

(c) For the purpose of this section, an 

unsafe takeoff configuration is the 

inability to rotate or the inability to 

prevent an immediate stall after 

rotation. 

■ 28. Amend § 23.735 by revising 

paragraph (e) to read as follows: 

§ 23.735 Brakes. 

* * * * * 

(e) For airplanes required to meet 

§ 23.55, the rejected takeoff brake 

kinetic energy capacity rating of each 

main wheel brake assembly may not be 

less than the kinetic energy absorption 

requirements determined under either 

of the following methods— 

(1) The brake kinetic energy 

absorption requirements must be based 

on a conservative rational analysis of 

the sequence of events expected during 

a rejected takeoff at the design takeoff 

weight. 

(2) Instead of a rational analysis, the 

kinetic energy absorption requirements 

for each main wheel brake assembly 

may be derived from the following 

formula— 

KE = 0.0443 WV2/N where; 

KE = Kinetic energy per wheel (ft.-lbs.); 

W = Design takeoff weight (lbs.); 

V = Ground speed, in knots, associated 

with the maximum value of V1

selected in accordance with 

§ 23.51(c)(1); 

N = Number of main wheels with 

brakes. 

■ 29. Amend § 23.777 by revising 

paragraph (d) to read as follows: 

§ 23.777 Cockpit controls. 

* * * * * 

(d) When separate and distinct control 

levers are co-located (such as located 

together on the pedestal), the control 

location order from left to right must be 

power (thrust) lever, propeller (rpm 

control), and mixture control (condition 

lever and fuel cut-off for turbinepowered airplanes). Power (thrust) 

levers must be easily distinguishable 

from other controls, and provide for 

accurate, consistent operation. 

Carburetor heat or alternate air control 

must be to the left of the throttle or at 

least eight inches from the mixture 

control when located other than on a 

pedestal. Carburetor heat or alternate air 

control, when located on a pedestal, 

must be aft or below the power (thrust) 

lever. Supercharger controls must be 

located below or aft of the propeller 

controls. Airplanes with tandem seating 

or single-place airplanes may utilize 

control locations on the left side of the 

cabin compartment; however, location 

order from left to right must be power 

(thrust) lever, propeller (rpm control), 

and mixture control. 

* * * * * 

■ 30. Amend § 23.807 by adding a new 

paragraph (e)(3) to read as follows: 

§ 23.807 Emergency exits. 

* * * * * 

(e) * * * 

(3) In lieu of paragraph (e)(2) of this 

section, if any side exit(s) cannot be 

above the waterline, a device may be 

placed at each of such exit(s) prior to 

ditching. This device must slow the 

inflow of water when such exit(s) is 

opened with the airplane ditched. For 

commuter category airplanes, the clear 

opening of such exit(s) must meet the 

requirements defined in paragraph (d) of 

this section. 

■ 31. Amend § 23.831 by adding 

paragraphs (c) and (d) to read as follows: 

§ 23.831 Ventilation. 

* * * * * 

(c) For jet pressurized airplanes that 

operate at altitudes above 41,000 feet, 

under normal operating conditions and 

in the event of any probable failure 

conditions of any system which would 

adversely affect the ventilating air, the 

ventilation system must provide 

reasonable passenger comfort. The 

ventilation system must also provide a 

sufficient amount of uncontaminated air 

to enable the flight crew members to 

perform their duties without undue 

discomfort or fatigue. For normal 

operating conditions, the ventilation 

system must be designed to provide 

each occupant with at least 0.55 pounds 

of fresh air per minute. In the event of 

the loss of one source of fresh air, the 

supply of fresh airflow may not be less 

than 0.4 pounds per minute for any 

period exceeding five minutes. 

(d) For jet pressurized airplanes that 

operate at altitudes above 41,000 feet, 

other probable and improbable 

Environmental Control System failure 

conditions that adversely affect the 

passenger and flight crew compartment 

environmental conditions may not affect 

flight crew performance so as to result 

in a hazardous condition, and no 

occupant shall sustain permanent 

physiological harm. 

■ 32. Amend § 23.841 by revising 

paragraphs (a) and (b)(6), and by adding 

paragraphs (c) and (d) to read as follows: 

§ 23.841 Pressurized cabins. 

(a) If certification for operation above 

25,000 feet is requested, the airplane 

must be able to maintain a cabin 

pressure altitude of not more than 

15,000 feet, in the event of any probable 

failure condition in the pressurization 

system. During decompression, the 

cabin altitude may not exceed 15,000 

feet for more than 10 seconds and 

25,000 feet for any duration. 

(b) * * * 

(6) Warning indication at the pilot 

station to indicate when the safe or 

preset pressure differential is exceeded 

and when a cabin pressure altitude of 

10,000 feet is exceeded. The 10,000 foot 

cabin altitude warning may be increased 

up to 15,000 feet for operations from 

high altitude airfields (10,000 to 15,000 

feet) provided: 

(i) The landing or the take off modes 

(normal or high altitude) are clearly 

indicated to the flight crew. 

(ii) Selection of normal or high 

altitude airfield mode requires no more 

than one flight crew action and goes to 

normal airfield mode at engine stop. 

(iii) The pressurization system is 

designed to ensure cabin altitude does 

not exceed 10,000 feet when in flight 

above flight level (FL) 250. 

(iv) The pressurization system and 

cabin altitude warning system is 

designed to ensure cabin altitude 

warning at 10,000 feet when in flight 

above FL250. 

* * * * * 

(c) If certification for operation above 

41,000 feet and not more than 45,000 

feet is requested— 

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(1) The airplane must prevent cabin 

pressure altitude from exceeding the 

following after decompression from any 

probable pressurization system failure 

in conjunction with any undetected, 

latent pressurization system failure 

condition: 

(i) If depressurization analysis shows 

that the cabin altitude does not exceed 

25,000 feet, the pressurization system 

must prevent the cabin altitude from 

exceeding the cabin altitude-time 

history shown in Figure 1 of this 

section. 

(ii) Maximum cabin altitude is limited 

to 30,000 feet. If cabin altitude exceeds 

25,000 feet, the maximum time the 

cabin altitude may exceed 25,000 feet is 

2 minutes; time starting when the cabin 

altitude exceeds 25,000 feet and ending 

when it returns to 25,000 feet. 

(2) The airplane must prevent cabin 

pressure altitude from exceeding the 

following after decompression from any 

single pressurization system failure in 

conjunction with any probable fuselage 

damage: 

(i) If depressurization analysis shows 

that the cabin altitude does not exceed 

37,000 feet, the pressurization system 

must prevent the cabin altitude from 

exceeding the cabin altitude-time 

history shown in Figure 2 of this 

section. 

(ii) Maximum cabin altitude is limited 

to 40,000 feet. If cabin altitude exceeds 

37,000 feet, the maximum time the 

cabin altitude may exceed 25,000 feet is 

2 minutes; time starting when the cabin 

altitude exceeds 25,000 feet and ending 

when it returns to 25,000 feet. 

(3) In showing compliance with 

paragraphs (c)(1) and (c)(2) of this 

section, it may be assumed that an 

emergency descent is made by an 

approved emergency procedure. A 

17-second flight crew recognition and 

reaction time must be applied between 

cabin altitude warning and the initiation 

of an emergency descent. Fuselage 

structure, engine and system failures are 

to be considered in evaluating the cabin 

decompression. 


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(d) If certification for operation above 

45,000 feet and not more than 51,000 

feet is requested— 

(1) Pressurized cabins must be 

equipped to provide a cabin pressure 

altitude of not more than 8,000 feet at 

the maximum operating altitude of the 

airplane under normal operating 

conditions. 

(2) The airplane must prevent cabin 

pressure altitude from exceeding the 

following after decompression from any 

failure condition not shown to be 

extremely improbable: 

(i) Twenty-five thousand (25,000) feet 

for more than 2 minutes; or 

(ii) Forty thousand (40,000) feet for 

any duration. 

(3) Fuselage structure, engine and 

system failures are to be considered in 

evaluating the cabin decompression. 

(4) In addition to the cabin altitude 

indicating means in (b)(6) of this 

section, an aural or visual signal must 

be provided to warn the flight crew 

when the cabin pressure altitude 

exceeds 10,000 feet. 

(5) The sensing system and pressure 

sensors necessary to meet the 

requirements of (b)(5), (b)(6), and (d)(4) 

of this section and § 23.1447(e), must, in 

the event of low cabin pressure, actuate 

the required warning and automatic 

presentation devices without any delay 

that would significantly increase the 

hazards resulting from decompression. 

■ 33. Amend § 23.853 by revising 

paragraph (d)(2) to read as follows: 

§ 23.853 Passenger and crew 

compartment interiors. 

* * * * * 

(d) * * * 

(2) Lavatories must have ‘‘No 

Smoking’’ or ‘‘No Smoking in Lavatory’’ 

placards located conspicuously on each 

side of the entry door. 

* * * * * 

■ 34. Add a new § 23.856 to read as 

follows: 

§ 23.856 Thermal/acoustic insulation 

materials. 

Thermal/acoustic insulation material 

installed in the fuselage must meet the 

flame propagation test requirements of 

part II of Appendix F to this part, or 

other approved equivalent test 

requirements. This requirement does 

not apply to ‘‘small parts,’’ as defined in 

§ 23.853(d)(3)(v). 

■ 35. Amend § 23.903 by adding 

paragraph (b)(3) to read as follows: 

§ 23.903 Engines. 

* * * * * 

(b) * * * 

(3) For engines embedded in the 

fuselage behind the cabin, the effects of 

a fan exiting forward of the inlet case 

(fan disconnect) must be addressed, the 

passengers must be protected, and the 

airplane must be controllable to allow 

for continued safe flight and landing. 

* * * * * 

■ 36. Amend § 23.1165 by revising 

paragraph (f) to read as follows: 

§ 23.1165 Engine ignition systems. 

* * * * * 

(f) In addition, for commuter category 

airplanes, each turbine engine ignition 

system must be an essential electrical 

load. 

■ 37. Amend § 23.1193 by revising 

paragraph (g) to read as follows: 

§ 23.1193 Cowling and nacelle. 

* * * * * 

(g) In addition, for all airplanes with 

engine(s) embedded in the fuselage or in 

pylons on the aft fuselage, the airplane 

must be designed so that no fire 

originating in any engine compartment 

can enter, either through openings or by 

burn-through, any other region where it 

would create additional hazards. 

■ 38. Amend § 23.1195 by revising the 

introductory text of paragraph (a) and by 

revising paragraph (a)(2) to read as 

follows: 

§ 23.1195 Fire extinguishing systems. 

(a) For all airplanes with engine(s) 

embedded in the fuselage or in pylons 

on the aft fuselage, fire extinguishing 


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systems must be installed and 

compliance shown with the following: 

* * * * * 

(2) The fire extinguishing system, the 

quantity of the extinguishing agent, the 

rate of discharge, and the discharge 

distribution must be adequate to 

extinguish fires. An individual ‘‘one 

shot’’ system may be used, except for 

engine(s) embedded in the fuselage, 

where a ‘‘two shot’’ system is required. 

* * * * * 

■ 39. Amend § 23.1197 by revising the 

introductory text to read as follows: 

§ 23.1197 Fire extinguishing agents. 

For all airplanes with engine(s) 

embedded in the fuselage or in pylons 

on the aft fuselage the following applies: 

* * * * * 

■ 40. Amend § 23.1199 by revising the 

introductory text to read as follows: 

§ 23.1199 Extinguishing agent containers. 

For all airplanes with engine(s) 

embedded in the fuselage or in pylons 

on the aft fuselage the following applies: 

* * * * * 

■ 41. Amend § 23.1201 by revising the 

introductory text to read as follows: 

§ 23.1201 Fire extinguishing systems 

materials. 

For all airplanes with engine(s) 

embedded in the fuselage or in pylons 

on the aft fuselage the following applies: 

* * * * * 

■ 42. Revise § 23.1301 by revising 

paragraphs (b) and (c) and by removing 

paragraph (d) to read as follows: 

§ 23.1301 Function and installation. 

* * * * * 

(b) Be labeled as to its identification, 

function, or operating limitations, or 

any applicable combination of these 

factors; and 

(c) Be installed according to 

limitations specified for that equipment. 

* * * * * 

■ 43. Amend § 23.1303 by revising 

paragraph (c) to read as follows: 

§ 23.1303 Flight and navigation 

instruments. 

* * * * * 

(c) A magnetic direction indicator. 

* * * * * 

■ 44. Revise § 23.1309 to read as 

follows: 

§ 23.1309 Equipment, systems, and 

installations. 

The requirements of this section, 

except as identified in paragraphs (a) 

through (d), are applicable, in addition 

to specific design requirements of part 

23, to any equipment or system as 

installed in the airplane. This section is 

a regulation of general requirements and 

does not supersede any requirements 

contained in another section of part 23. 

(a) The airplane equipment and 

systems must be designed and installed 

so that: 

(1) Those required for type 

certification or by operating rules 

perform as intended under the airplane 

operating and environmental 

conditions, including the indirect 

effects of lightning strikes. 

(2) Any equipment and system does 

not adversely affect the safety of the 

airplane or its occupants, or the proper 

functioning of those covered by 

paragraph (a)(1) of this section. 

(b) Minor, major, hazardous, or 

catastrophic failure condition(s), which 

occur during Type Inspection 

Authorization or FAA flightcertification testing, must have root 

cause analysis and corrective action. 

(c) The airplane systems and 

associated components considered 

separately and in relation to other 

systems, must be designed and installed 

so that: 

(1) Each catastrophic failure condition 

is extremely improbable and does not 

result from a single failure; 

(2) Each hazardous failure condition 

is extremely remote; and 

(3) Each major failure condition is 

remote. 

(d) Information concerning an unsafe 

system operating condition must be 

provided in a timely manner to the crew 

to enable them to take appropriate 

corrective action. An appropriate alert 

must be provided if immediate pilot 

awareness and immediate or subsequent 

corrective action is required. Systems 

and controls, including indications and 

annunciations, must be designed to 

minimize crew errors which could 

create additional hazards. 

■ 45. Add a new § 23.1310 to read as 

follows: 

§ 23.1310 Power source capacity and 

distribution. 

(a) Each installation whose 

functioning is required for type 

certification or under operating rules 

and that requires a power supply is an 

‘‘essential load’’ on the power supply. 

The power sources and the system must 

be able to supply the following power 

loads in probable operating 

combinations and for probable 

durations: 

(1) Loads connected to the system 

with the system functioning normally. 

(2) Essential loads, after failure of any 

one prime mover, power converter, or 

energy storage device. 

(3) Essential loads after failure of— 

(i) Any one engine on two-engine 

airplanes; and 

(ii) Any two engines on airplanes with 

three or more engines. 

(4) Essential loads for which an 

alternate source of power is required, 

after any failure or malfunction in any 

one power supply system, distribution 

system, or other utilization system. 

(b) In determining compliance with 

paragraphs (a)(2) and (3) of this section, 

the power loads may be assumed to be 

reduced under a monitoring procedure 

consistent with safety in the kinds of 

operation authorized. Loads not 

required in controlled flight need not be 

considered for the two-engineinoperative condition on airplanes with 

three or more engines. 

■ 46. Amend § 23.1311 by revising 

paragraphs (a)(5), (a)(6), (a)(7), and 

paragraph (b) to read as follows: 

§ 23.1311 Electronic display instrument 

systems. 

(a) * * * 

(5) For certification for Instrument 

Flight Rules (IFR) operations, have an 

independent magnetic direction 

indicator and either an independent 

secondary mechanical altimeter, 

airspeed indicator, and attitude 

instrument or an electronic display 

parameters for the altitude, airspeed, 

and attitude that are independent from 

the airplane’s primary electrical power 

system. These secondary instruments 

may be installed in panel positions that 

are displaced from the primary 

positions specified by § 23.1321(d), but 

must be located where they meet the 

pilot’s visibility requirements of 

§ 23.1321(a). 

(6) Incorporate sensory cues that 

provide a quick glance sense of rate and, 

where appropriate, trend information to 

the parameter being displayed to the 

pilot. 

(7) Incorporate equivalent visual 

displays of the instrument markings 

required by §§ 23.1541 through 23.1553, 

or visual displays that alert the pilot to 

abnormal operational values or 

approaches to established limitation 

values, for each parameter required to 

be displayed by this part. 

(b) The electronic display indicators, 

including their systems and 

installations, and considering other 

airplane systems, must be designed so 

that one display of information essential 

for continued safe flight and landing 

will be available within one second to 

the crew by a single pilot action or by 

automatic means for continued safe 

operation, after any single failure or 

probable combination of failures. 

* * * * * 

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■ 47. Amend § 23.1323 by revising 

paragraph (e) to read as follows: 

§ 23.1323 Airspeed indicating system. 

* * * * * 

(e) In addition, for normal, utility, and 

acrobatic category multiengine jets of 

more than 6,000 pounds maximum 

weight and commuter category 

airplanes, each system must be 

calibrated to determine the system error 

during the accelerate-takeoff ground 

run. The ground run calibration must be 

determined— 

(1) From 0.8 of the minimum value of 

V1 to the maximum value of V2, 

considering the approved ranges of 

altitude and weight; and 

(2) The ground run calibration must 

be determined assuming an engine 

failure at the minimum value of V1. 

* * * * * 

■ 48. Amend § 23.1331 by revising 

paragraph (c) to read as follows: 

§ 23.1331 Instruments using a power 

source. 

* * * * * 

(c) For certification for Instrument 

Flight Rules (IFR) operations and for the 

heading, altitude, airspeed, and attitude, 

there must be at least: 

(1) Two independent sources of 

power (not driven by the same engine 

on multiengine airplanes), and a manual 

or an automatic means to select each 

power source; or 

(2) A separate display of parameters 

for heading, altitude, airspeed, and 

attitude that has a power source 

independent from the airplane’s 

primary electrical power system. 

■ 49. Amend § 23.1353 by revising 

paragraph (h) to read as follows: 

§ 23.1353 Storage battery design and 

installation. 

* * * * * 

(h)(1) In the event of a complete loss 

of the primary electrical power 

generating system, the battery must be 

capable of providing electrical power to 

those loads that are essential to 

continued safe flight and landing for: 

(i) At least 30 minutes for airplanes 

that are certificated with a maximum 

altitude of 25,000 feet or less; and 

(ii) At least 60 minutes for airplanes 

that are certificated with a maximum 

altitude over 25,000 feet. 

(2) The time period includes the time 

to recognize the loss of generated power 

and to take appropriate load shedding 

action. 

■ 50. Amend § 23.1431, paragraph (a) to 

read as follows: 

§ 23.1431 Electronic equipment. 

(a) In showing compliance with 

§ 23.1309(a), (b), and (c) with respect to 

radio and electronic equipment and 

their installations, critical 

environmental conditions must be 

considered. 

* * * * * 

■ 51. Revise § 23.1443 to read as 

follows: 

§ 23.1443 Minimum mass flow of 

supplemental oxygen. 

(a) If the airplane is to be certified 

above 41,000 feet, a continuous flow 

oxygen system must be provided for 

each passenger. 

(b) If continuous flow oxygen 

equipment is installed, an applicant 

must show compliance with the 

requirements of either paragraphs (b)(1) 

and (b)(2) or paragraph (b)(3) of this 

section: 

(1) For each passenger, the minimum 

mass flow of supplemental oxygen 

required at various cabin pressure 

altitudes may not be less than the flow 

required to maintain, during inspiration 

and while using the oxygen equipment 

(including masks) provided, the 

following mean tracheal oxygen partial 

pressures: 

(i) At cabin pressure altitudes above 

10,000 feet up to and including 18,500 

feet, a mean tracheal oxygen partial 

pressure of 100mm Hg when breathing 

15 liters per minute, Body Temperature, 

Pressure, Saturated (BTPS) and with a 

tidal volume of 700cc with a constant 

time interval between respirations. 

(ii) At cabin pressure altitudes above 

18,500 feet up to and including 40,000 

feet, a mean tracheal oxygen partial 

pressure of 83.8mm Hg when breathing 

30 liters per minute, BTPS, and with a 

tidal volume of 1,100cc with a constant 

time interval between respirations. 

(2) For each flight crewmember, the 

minimum mass flow may not be less 

than the flow required to maintain, 

during inspiration, a mean tracheal 

oxygen partial pressure of 149mm Hg 

when breathing 15 liters per minute, 

BTPS, and with a maximum tidal 

volume of 700cc with a constant time 

interval between respirations. 

(3) The minimum mass flow of 

supplemental oxygen supplied for each 

user must be at a rate not less than that 

shown in the following figure for each 

altitude up to and including the 

maximum operating altitude of the 

airplane. 

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75762 Federal Register / Vol. 76, No. 232 / Friday, December 2, 2011 / Rules and Regulations 

(c) If demand equipment is installed 

for use by flight crewmembers, the 

minimum mass flow of supplemental 

oxygen required for each flight 

crewmember may not be less than the 

flow required to maintain, during 

inspiration, a mean tracheal oxygen 

partial pressure of 122mm Hg up to and 

including a cabin pressure altitude of 

35,000 feet, and 95 percent oxygen 

between cabin pressure altitudes of 

35,000 and 40,000 feet, when breathing 

20 liters per minutes BTPS. In addition, 

there must be means to allow the flight 

crew to use undiluted oxygen at their 

discretion. 

(d) If first-aid oxygen equipment is 

installed, the minimum mass flow of 

oxygen to each user may not be less 

than 4 liters per minute, STPD. 

However, there may be a means to 

decrease this flow to not less than 2 

liters per minute, STPD, at any cabin 

altitude. The quantity of oxygen 

required is based upon an average flow 

rate of 3 liters per minute per person for 

whom first-aid oxygen is required. 

(e) As used in this section: 

(1) BTPS means Body Temperature, 

and Pressure, Saturated (which is 37 °C, 

and the ambient pressure to which the 

body is exposed, minus 47mm Hg, 

which is the tracheal pressure displaced 

by water vapor pressure when the 

breathed air becomes saturated with 

water vapor at 37 °C). 

(2) STPD means Standard, 

Temperature, and Pressure, Dry (which 

is 0 °C at 760mm Hg with no water 

vapor). 

■ 52. Amend § 23.1445 by adding a new 

paragraph (c) to read as follows: 

§ 23.1445 Oxygen distribution system. 

* * * * * 

(c) If the flight crew and passengers 

share a common source of oxygen, a 

means to separately reserve the 

minimum supply required by the flight 

crew must be provided. 

■ 53. Amend § 23.1447 by adding a new 

paragraph (g) to read as follows: 

§ 23.1447 Equipment standards for oxygen 

dispensing units. 

* * * * * 

(g) If the airplane is to be certified for 

operation above 41,000 feet, a quickdonning oxygen mask system, with a 

pressure demand, mask mounted 

regulator must be provided for the flight 

crew. This dispensing unit must be 

immediately available to the flight crew 

when seated at their station and 

installed so that it: 

(1) Can be placed on the face from its 

ready position, properly secured, sealed, 

and supplying oxygen upon demand, 

with one hand, within five seconds and 

without disturbing eyeglasses or causing 

delay in proceeding with emergency 

duties; and 

(2) Allows, while in place, the 

performance of normal communication 

functions. 

■ 54. Amend § 23.1505 by revising 

paragraph (c) to read as follows: 

§ 23.1505 Airspeed limitations. 

* * * * * 

(c)(1) Paragraphs (a) and (b) of this 

section do not apply to turbine airplanes 

or to airplanes for which a design diving 

speed VD/MD is established under 

§ 23.335(b)(4). For those airplanes, a 

maximum operating limit speed (VMO/ 

MMO airspeed or Mach number, 

whichever is critical at a particular 

altitude) must be established as a speed 

that may not be deliberately exceeded in 

any regime of flight (climb, cruise, or 

descent) unless a higher speed is 

authorized for flight test or pilot training 

operations. 

(2) VMO/MMO must be established so 

that it is not greater than the design 

cruising speed VC/MC and so that it is 

sufficiently below VD/MD, or VDF/MDF

for jets, and the maximum speed shown 

under § 23.251 to make it highly 

improbable that the latter speeds will be 

inadvertently exceeded in operations. 

(3) The speed margin between VMO/ 

MMO and VD/MD, or VDF/MDF for jets, 

may not be less than that determined 

under § 23.335(b), or the speed margin 

found necessary in the flight tests 

conducted under § 23.253. 

■ 55. Amend § 23.1545 by revising 

paragraph (d) to read as follows: 

§ 23.1545 Airspeed indicator. 

* * * * * 

(d) Paragraphs (b)(1) through (b)(4) 

and paragraph (c) of this section do not 

apply to airplanes for which a 

maximum operating speed VMO/MMO is 

established under § 23.1505(c). For 

those airplanes, there must either be a 

maximum allowable airspeed indication 


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showing the variation of VMO/MMO with 

altitude or compressibility limitations 

(as appropriate), or a radial red line 

marking for VMO/MMO must be made at 

lowest value of VMO/MMO established 

for any altitude up to the maximum 

operating altitude for the airplane. 

■ 56. Amend § 23.1555 by adding a new 

paragraph (d)(3) to read as follows: 

§ 23.1555 Control markings. 

* * * * * 

(d) * * * 

(3) For fuel systems having a 

calibrated fuel quantity indication 

system complying with § 23.1337(b)(1) 

and accurately displaying the actual 

quantity of usable fuel in each selectable 

tank, no fuel capacity placards outside 

of the fuel quantity indicator are 

required. 

* * * * * 

■ 57. Amend § 23.1559 by adding a new 

paragraph (d) to read as follows: 

§ 23.1559 Operating limitations placard. 

* * * * * 

(d) The placard(s) required by this 

section need not be lighted. 

■ 58. Amend § 23.1563 by adding a new 

paragraph (d) to read as follows: 

§ 23.1563 Airspeed placard. 

* * * * * 

(d) The airspeed placard(s) required 

by this section need not be lighted if the 

landing gear operating speed is 

indicated on the airspeed indicator or 

other lighted area such as the landing 

gear control and the airspeed indicator 

has features such as low speed 

awareness that provide ample warning 

prior to VMC. 

■ 59. Amend § 23.1567 by adding a new 

paragraph (e) to read as follows: 

§ 23.1567 Flight maneuver placard. 

* * * * * 

(e) The placard(s) required by this 

section need not be lighted. 

■ 60. Amend § 23.1583 as follows: 

■ A. Revise the introductory text of 

paragraphs (c)(3) and (c)(4); 

■ B. Redesignate paragraphs (c)(4)(iii) 

and (c)(4)(iv) as paragraphs (c)(4)(ii)(A) 

and (c)(4)(ii)(B); and 

■ C. Revise paragraph (c)(5) 

introductory text: 

§ 23.1583 Operating limitations. 

* * * * * 

(c) * * * 

(3) For reciprocating engine-powered 

airplanes of more than 6,000 pounds 

maximum weight, single-engine 

turbines, and multiengine jets 6,000 

pounds or less maximum weight in the 

normal, utility, and acrobatic category, 

performance operating limitations as 

follows— 

* * * * * 

(4) For normal, utility, and acrobatic 

category multiengine jets over 6,000 

pounds and commuter category 

airplanes, the maximum takeoff weight 

for each airport altitude and ambient 

temperature within the range selected 

by the applicant at which— 

* * * * * 

(5) For normal, utility, and acrobatic 

category multiengine jets over 6,000 

pounds and commuter category 

airplanes, the maximum landing weight 

for each airport altitude within the 

range selected by the applicant at 

which— 

* * * * * 

■ 61. Amend § 23.1585 by revising 

paragraph (f) introductory text to read as 

follows: 

§ 23.1585 Operating procedures. 

* * * * * 

(f) In addition to paragraphs (a) and 

(c) of this section, for normal, utility, 

and acrobatic category multiengine jets 

weighing over 6,000 pounds, and 

commuter category airplanes, the 

information must include the following: 

* * * * * 

■ 62. Amend § 23.1587 by revising 

paragraph (d) introductory text to read 

as follows: 

§ 23.1587 Performance information. 

* * * * * 

(d) In addition to paragraph (a) of this 

section, for normal, utility, and 

acrobatic category multiengine jets 

weighing over 6,000 pounds, and 

commuter category airplanes, the 

following information must be 

furnished— 

* * * * * 

■ 63. Amend Appendix F to Part 23 as 

follows: 

■ A. Redesignate the existing text as Part 

I and add a new Part I heading; 

■ B. Add a new Part II. 

Appendix F to Part 23—Test Procedure 

Part I—Acceptable Test Procedure for SelfExtinguishing Materials for Showing 

Compliance With §§ 23.853, 23.855, and 

23.1359 

* * * * * 

Part II—Test Method To Determine the 

Flammability and Flame Propagation 

Characteristics of Thermal/Acoustic 

Insulation Materials 

Use this test method to evaluate the 

flammability and flame propagation 

characteristics of thermal/acoustic insulation 

when exposed to both a radiant heat source 

and a flame. 

(a) Definitions. 

Flame propagation means the furthest 

distance of the propagation of visible flame 

towards the far end of the test specimen, 

measured from the midpoint of the ignition 

source flame. Measure this distance after 

initially applying the ignition source and 

before all flame on the test specimen is 

extinguished. The measurement is not a 

determination of burn length made after the 

test. 

Radiant heat source means an electric or 

air propane panel. 

Thermal/acoustic insulation means a 

material or system of materials used to 

provide thermal and/or acoustic protection. 

Examples include fiberglass or other batting 

material encapsulated by a film covering and 

foams. 

Zero point means the point of application 

of the pilot burner to the test specimen. 

(b) Test apparatus. 

BILLING CODE 4910–13–P 

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75764 Federal Register / Vol. 76, No. 232 / Friday, December 2, 2011 / Rules and Regulations 

(1) Radiant panel test chamber. Conduct 

tests in a radiant panel test chamber (see 

figure F1 above). Place the test chamber 

under an exhaust hood to facilitate clearing 

the chamber of smoke after each test. The 

radiant panel test chamber must be an 

enclosure 55 inches (1397 mm) long by 19.5 

inches (495 mm) deep by 28 inches (710 mm) 

to 30 inches (maximum) (762 mm) above the 

test specimen. Insulate the sides, ends, and 

top with a fibrous ceramic insulation, such 

as Kaowool MTM board. On the front side, 

provide a 52 by 12-inch (1321 by 305 mm) 

draft-free, high-temperature, glass window 

for viewing the sample during testing. Place 

a door below the window to provide access 

to the movable specimen platform holder. 

The bottom of the test chamber must be a 

sliding steel platform that has provision for 

securing the test specimen holder in a fixed 

and level position. The chamber must have 

an internal chimney with exterior 

dimensions of 5.1 inches (129 mm) wide, by 

16.2 inches (411 mm) deep by 13 inches (330 

mm) high at the opposite end of the chamber 

from the radiant energy source. The interior 

dimensions must be 4.5 inches (114 mm) 

wide by 15.6 inches (395 mm) deep. The 

chimney must extend to the top of the 

chamber (see figure F2). 

(2) Radiant heat source. Mount the radiant 

heat energy source in a cast iron frame or 

equivalent. An electric panel must have six, 

3-inch wide emitter strips. The emitter strips 

must be perpendicular to the length of the 

panel. The panel must have a radiation 

surface of 127⁄8 by 181⁄2 inches (327 by 470 

mm). The panel must be capable of operating 

at temperatures up to 1300 °F (704 °C). An 

air propane panel must be made of a porous 

refractory material and have a radiation 

surface of 12 by 18 inches (305 by 457 mm). 

The panel must be capable of operating at 

temperatures up to 1,500 °F (816 °C). See 

figures F3a and F3b. 


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BILLING CODE 4910–13–C 

(i) Electric radiant panel. The radiant panel 

must be 3-phase and operate at 208 volts. A 

single-phase, 240 volt panel is also 

acceptable. Use a solid-state power controller 

and microprocessor-based controller to set 

the electric panel operating parameters. 

(ii) Gas radiant panel. Use propane (liquid 

petroleum gas—2.1 UN 1075) for the radiant 

panel fuel. The panel fuel system must 

consist of a venturi-type aspirator for mixing 

gas and air at approximately atmospheric 

pressure. Provide suitable instrumentation 

for monitoring and controlling the flow of 

fuel and air to the panel. Include an air flow 

gauge, an air flow regulator, and a gas 

pressure gauge. 

(iii) Radiant panel placement. Mount the 

panel in the chamber at 30 degrees to the 

horizontal specimen plane, and 71⁄2 inches 

above the zero point of the specimen. 

(3) Specimen holding system. 

(i) The sliding platform serves as the 

housing for test specimen placement. 

Brackets may be attached (via wing nuts) to 

the top lip of the platform in order to 

accommodate various thicknesses of test 

specimens. Place the test specimens on a 

sheet of Kaowool MTM board or 1260 

Standard Board (manufactured by Thermal 

Ceramics and available in Europe), or 

equivalent, either resting on the bottom lip of 

the sliding platform or on the base of the 

brackets. It may be necessary to use multiple 

sheets of material based on the thickness of 

the test specimen (to meet the sample height 

requirement). Typically, these nonVerDate Mar<15>2010 23:10 Dec 01, 2011 Jkt 226001 PO 00000 Frm 00031 Fmt 4701 Sfmt 4700 E:\FR\FM\02DER3.SGM 02DER3

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75766 Federal Register / Vol. 76, No. 232 / Friday, December 2, 2011 / Rules and Regulations 

combustible sheets of material are available 

in 1⁄4-inch (6 mm) thicknesses. See figure F4. 

A sliding platform that is deeper than the 

2-inch (50.8mm) platform shown in figure F4 

is also acceptable as long as the sample 

height requirement is met. 

(ii) Attach a 1⁄2-inch (13 mm) piece of 

Kaowool MTM board or other high 

temperature material measuring 411⁄2 by 81⁄4

inches (1054 by 210 mm) to the back of the 

platform. This board serves as a heat retainer 

and protects the test specimen from excessive 

preheating. The height of this board may not 

impede the sliding platform movement (in 

and out of the test chamber). If the platform 

has been fabricated such that the back side 

of the platform is high enough to prevent 

excess preheating of the specimen when the 

sliding platform is out, a retainer board is not 

necessary. 

(iii) Place the test specimen horizontally on 

the non-combustible board(s). Place a steel 

retaining/securing frame fabricated of mild 

steel, having a thickness of 1⁄8-inch (3.2 mm) 

and overall dimensions of 23 by 131⁄8 inches 

(584 by 333 mm) with a specimen opening 

of 19 by 103⁄4 inches (483 by 273 mm) over 

the test specimen. The front, back, and right 

portions of the top flange of the frame must 

rest on the top of the sliding platform, and 

the bottom flanges must pinch all 4 sides of 

the test specimen. The right bottom flange 

must be flush with the sliding platform. See 

figure F5. 


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(4) Pilot Burner. The pilot burner used to 

ignite the specimen must be a 

BernzomaticTM commercial propane venturi 

torch with an axially symmetric burner tip 

and a propane supply tube with an orifice 

diameter of 0.006 inches (0.15 mm). The 

length of the burner tube must be 27⁄8 inches 

(71 mm). The propane flow must be adjusted 

via gas pressure through an in-line regulator 

to produce a blue inner cone length of 3⁄4- 

inch (19 mm). A 3⁄4-inch (19 mm) guide (such 

as a thin strip of metal) may be soldered to 

the top of the burner to aid in setting the 

flame height. The overall flame length must 

be approximately 5 inches long (127 mm). 

Provide a way to move the burner out of the 

ignition position so that the flame is 

horizontal and at least 2 inches (50 mm) 

above the specimen plane. See figure F6. 

(5) Thermocouples. Install a 24 American 

Wire Gauge (AWG) Type K (ChromelAlumel) thermocouple in the test chamber 

for temperature monitoring. Insert it into the 

chamber through a small hole drilled through 

the back of the chamber. Place the 

thermocouple so that it extends 11 inches 

(279 mm) out from the back of the chamber 

wall, 111⁄2 inches (292 mm) from the right 

side of the chamber wall, and is 2 inches 

(51 mm) below the radiant panel. The use of 

other thermocouples is optional. 

(6) Calorimeter. The calorimeter must be a 

one-inch cylindrical water-cooled, total heat 

flux density, foil type Gardon Gage that has 

a range of 0 to 5 BTU/ft 2-second (0 to 5.7 

Watts/cm 2). 

(7) Calorimeter calibration specification 

and procedure. 

(i) Calorimeter specification. 

(A) Foil diameter must be 0.25 +/¥0.005 

inches (6.35 +/¥0.13 mm). 

(B) Foil thickness must be 0.0005 +/ 

¥0.0001 inches (0.013 +/¥ 0.0025 mm). 

(C) Foil material must be thermocouple 

grade Constantan. 

(D) Temperature measurement must be a 

Copper Constantan thermocouple. 

(E) The copper center wire diameter must 

be 0.0005 inches (0.013 mm). 

(F) The entire face of the calorimeter must 

be lightly coated with ‘‘Black Velvet’’ paint 

having an emissivity of 96 or greater. 

(ii) Calorimeter calibration. 

(A) The calibration method must be by 

comparison to a like standardized transducer. 


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75768 Federal Register / Vol. 76, No. 232 / Friday, December 2, 2011 / Rules and Regulations 

(B) The standardized transducer must meet 

the specifications given in paragraph II(b)(6) 

of this appendix. 

(C) Calibrate the standard transducer 

against a primary standard traceable to the 

National Institute of Standards and 

Technology (NIST). 

(D) The method of transfer must be a 

heated graphite plate. 

(E) The graphite plate must be electrically 

heated, have a clear surface area on each side 

of the plate of at least 2 by 2 inches (51 by 

51 mm), and be 1⁄8-inch +/¥ 1⁄16-inch thick 

(3.2 +/¥ 1.6 mm). 

(F) Center the 2 transducers on opposite 

sides of the plates at equal distances from the 

plate. 

(G) The distance of the calorimeter to the 

plate must be no less than 0.0625 inches 

(1.6 mm), and no greater than 0.375 inches 

(9.5 mm). 

(H) The range used in calibration must be 

at least 0–3.5 BTUs/ft 2-second (0–3.9 Watts/ 

cm 2) and no greater than 0–5.7 BTUs/ft 2- 

second (0–6.4 Watts/cm 2). 

(I) The recording device used must record 

the 2 transducers simultaneously or at least 

within 1⁄10 of each other. 

(8) Calorimeter fixture. With the sliding 

platform pulled out of the chamber, install 

the calorimeter holding frame and place a 

sheet of non-combustible material in the 

bottom of the sliding platform adjacent to the 

holding frame. This will prevent heat losses 

during calibration. The frame must be 131⁄8

inches (333 mm) deep (front to back) by 8 

inches (203 mm) wide and must rest on the 

top of the sliding platform. It must be 

fabricated of 1⁄8-inch (3.2 mm) flat stock steel 

and have an opening that accommodates a 

1⁄2-inch (12.7 mm) thick piece of refractory 

board, which is level with the top of the 

sliding platform. The board must have three 

1-inch (25.4 mm) diameter holes drilled 

through the board for calorimeter insertion. 

The distance to the radiant panel surface 

from the centerline of the first hole (‘‘zero’’ 

position) must be 71⁄2 ± 1⁄8-inches (191 ± 3 

mm). The distance between the centerline of 

the first hole to the centerline of the second 

hole must be 2 inches (51 mm). It must also 

be the same distance from the centerline of 

the second hole to the centerline of the third 

hole. See figure F7. A calorimeter holding 

frame that differs in construction is 

acceptable as long as the height from the 

centerline of the first hole to the radiant 

panel and the distance between holes is the 

same as described in this paragraph. 

(9) Instrumentation. Provide a calibrated 

recording device with an appropriate range 

or a computerized data acquisition system to 

measure and record the outputs of the 

calorimeter and the thermocouple. The data 

acquisition system must be capable of 

recording the calorimeter output every 

second during calibration. 

(10) Timing device. Provide a stopwatch or 

other device, accurate to ± 1 second/hour, to 

measure the time of application of the pilot 

burner flame. 

(c) Test specimens. 

(1) Specimen preparation. Prepare and test 

a minimum of three test specimens. If an 

oriented film cover material is used, prepare 

and test both the warp and fill directions. 

(2) Construction. Test specimens must 

include all materials used in construction of 

the insulation (including batting, film, scrim, 

tape, etc.). Cut a piece of core material such 

as foam or fiberglass, and cut a piece of film 

cover material (if used) large enough to cover 

the core material. Heat sealing is the 

preferred method of preparing fiberglass 

samples, since they can be made without 

compressing the fiberglass (‘‘box sample’’). 

Cover materials that are not heat sealable 

may be stapled, sewn, or taped as long as the 

cover material is sufficiently over-cut to be 

drawn down the sides without compressing 

the core material. The fastening means 

should be as continuous as possible along the 

length of the seams. The specimen thickness 

must be of the same thickness as installed in 

the airplane. 

(3) Specimen Dimensions. To facilitate 

proper placement of specimens in the sliding 

platform housing, cut non-rigid core 

materials, such as fiberglass, 121⁄2 inches 

(318mm) wide by 23 inches (584mm) long. 

Cut rigid materials, such as foam, 111⁄2 ± 1⁄4

inches (292 mm ± 6mm) wide by 23 inches 

(584mm) long in order to fit properly in the 

sliding platform housing and provide a flat, 

exposed surface equal to the opening in the 

housing. 

(d) Specimen conditioning. Condition the 

test specimens at 70 ± 5 °F (21 ± 2 °C) and 

55 percent ± 10 percent relative humidity, for 

a minimum of 24 hours prior to testing. 

(e) Apparatus Calibration. 

(1) With the sliding platform out of the 

chamber, install the calorimeter holding 

frame. Push the platform back into the 

chamber and insert the calorimeter into the 

first hole (‘‘zero’’ position). See figure F7. 

Close the bottom door located below the 

sliding platform. The distance from the 

centerline of the calorimeter to the radiant 

panel surface at this point must be 71⁄2 inches 

± 1⁄8 (191 mm ± 3). Before igniting the radiant 

panel, ensure that the calorimeter face is 

clean and that there is water running through 

the calorimeter. 

(2) Ignite the panel. Adjust the fuel/air 

mixture to achieve 1.5 BTUs/feet2-second ± 

5 percent (1.7 Watts/cm2 ± 5 percent) at the 

‘‘zero’’ position. If using an electric panel, set 

the power controller to achieve the proper 

heat flux. Allow the unit to reach steady state 

(this may take up to 1 hour). The pilot burner 

must be off and in the down position during 

this time. 

(3) After steady-state conditions have been 

reached, move the calorimeter 2 inches (51 

mm) from the ‘‘zero’’ position (first hole) to 

position 1 and record the heat flux. Move the 

calorimeter to position 2 and record the heat 

flux. Allow enough time at each position for 

the calorimeter to stabilize. Table 1 depicts 

typical calibration values at the three 

positions. 


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Federal Register / Vol. 76, No. 232 / Friday, December 2, 2011 / Rules and Regulations 75769 

TABLE 1—CALIBRATION TABLE

Position BTU/feet 2 sec Watts/cm2

‘‘Zero’’ Position ........................................................................................................................................ 1.5 1.7 

Position 1 ................................................................................................................................................. 1.51–1.50–1.49 1.71–1.70–1.69 

Position 2 ................................................................................................................................................. 1.43–1.44 1.62–1.63 

(4) Open the bottom door, remove the 

calorimeter and holder fixture. Use caution 

as the fixture is very hot. 

(f) Test Procedure. 

(1) Ignite the pilot burner. Ensure that it is 

at least 2 inches (51 mm) above the top of 

the platform. The burner may not contact the 

specimen until the test begins. 

(2) Place the test specimen in the sliding 

platform holder. Ensure that the test sample 

surface is level with the top of the platform. 

At ‘‘zero’’ point, the specimen surface must 

be 71⁄2 inches ± 1⁄8 inch (191 mm ± 3) below 

the radiant panel. 

(3) Place the retaining/securing frame over 

the test specimen. It may be necessary (due 

to compression) to adjust the sample (up or 

down) in order to maintain the distance from 

the sample to the radiant panel (71⁄2 inches 

± 1⁄8 inch (191 mm ± 3) at ‘‘zero’’ position). 

With film/fiberglass assemblies, it is critical 

to make a slit in the film cover to purge any 

air inside. This allows the operator to 

maintain the proper test specimen position 

(level with the top of the platform) and to 

allow ventilation of gases during testing. A 

longitudinal slit, approximately 2 inches 

(51mm) in length, must be centered 3 inches 

± 1⁄2 inch (76mm ± 13mm) from the left flange 

of the securing frame. A utility knife is 

acceptable for slitting the film cover. 

(4) Immediately push the sliding platform 

into the chamber and close the bottom door. 

(5) Bring the pilot burner flame into 

contact with the center of the specimen at the 

‘‘zero’’ point and simultaneously start the 

timer. The pilot burner must be at a 27 degree 

angle with the sample and be approximately 

1⁄2 inch (12 mm) above the sample. See figure 

F7. A stop, as shown in figure F8, allows the 

operator to position the burner correctly each 

time. 

(6) Leave the burner in position for 15 

seconds and then remove to a position at 

least 2 inches (51 mm) above the specimen. 

(g) Report. 

(1) Identify and describe the test specimen. 

(2) Report any shrinkage or melting of the 

test specimen. 

(3) Report the flame propagation distance. 

If this distance is less than 2 inches, report 

this as a pass (no measurement required). 

(4) Report the after-flame time. 

(h) Requirements. 

(1) There must be no flame propagation 

beyond 2 inches (51 mm) to the left of the 

centerline of the pilot flame application. 

(2) The flame time after removal of the 

pilot burner may not exceed 3 seconds on 

any specimen. 

Issued in Washington, DC, on November 

16, 2011. 

J. Randolph Babbitt, 

Administrator. 

[FR Doc. 2011–30412 Filed 12–1–11; 8:45 am] 

BILLING CODE 4910–13–P 


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