41522 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Parts 1 and 23 

[Docket No. FAA–2009–0738; Notice No. 09– 

09] 

RIN 2120–AJ22 

Certification of Turbojets 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: This action proposes to 

enhance safety by amending the 

applicable standards for part 23 

turbojet-powered airplanes—which are 

commonly referred to as ‘‘turbojets’’—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 

levels of safety findings necessary to 

certificate light part 23 turbojets. The 

intended effect of the proposed changes 

would: Standardize and simplify the 

certification of part 23 turbojets; clarify 

areas of frequent non-standardization 

and misinterpretation, particularly for 

electronic equipment and system 

certification; and codify existing 

certification requirements in special 

conditions for new turbojets that 

incorporate new technologies. 

DATES: Send your comments on or 

before November 16, 2009. 

ADDRESSES: You may send comments 

identified by Docket Number FAA– 

2009–0738 using any of the following 

methods: 

• Federal eRulemaking Portal: Go to 

http://www.regulations.gov and follow 

the online instructions for sending your 

comments electronically. 

• Mail: Send comments to Docket 

Operations, M–30, U.S. Department of 

Transportation, 1200 New Jersey 

Avenue, SE., Room W12–140, West 

Building Ground Floor, Washington, DC 

20590–0001. 

• Hand Delivery or Courier: Bring 

comments to Docket Operations in 

Room W12–140 of the West Building 

Ground Floor at 1200 New Jersey 

Avenue, SE., Washington, DC, between 

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

Friday, except Federal holidays. 

• Fax: Fax comments to Docket 

Operations at 202–493–2251. 

For more information on the rulemaking 

process, see the SUPPLEMENTARY

INFORMATION section of this document. 

Privacy: We will post all comments 

we receive, without change, to http:// 

www.regulations.gov, including any 

personal information you provide. 

Using the search function of our docket 

Web site, anyone can find and read the 

electronic form of all comments 

received into any of our dockets, 

including the name of the individual 

sending the comment (or signing the 

comment for an association, business, 

labor union, etc.). You may review 

DOT’s complete Privacy Act Statement 

in the Federal Register published on 

April 11, 2000 (65 FR 19477–78) or you 

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

Docket: To read background 

documents or comments received, go to 

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

and follow the online instructions for 

accessing the docket. Or, go to Docket 

Operations in Room W12–140 of the 

West Building Ground Floor at 1200 

New Jersey Avenue, SE., Washington, 

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

through Friday, except Federal holidays. 

FOR FURTHER INFORMATION CONTACT: For 

technical questions concerning this 

proposed rule, contact Pat Mullen, 

Regulations and Policy, ACE–111, 

Federal Aviation Administration, 901 

Locust St., Kansas City, MO 64106; 

telephone: (816) 329–4111; facsimile 

(816) 329–4090; e-mail: 

pat.mullen@faa.gov. For legal questions 

concerning this proposed rule, contact 

Mary Ellen Loftus, ACE–7, Federal 

Aviation Administration, 901 Locust St., 

Kansas City, MO 64106; telephone: 

(816) 329–3764; e-mail: 

mary.ellen.loftus@faa.gov. 

SUPPLEMENTARY INFORMATION: Later in 

this preamble under the Additional 

Information section, we discuss how 

you can comment on this proposal and 

how we will handle your comments. 

Included in this discussion is related 

information about the docket, privacy, 

and the handling of proprietary or 

confidential business information. We 

also discuss how you can get a copy of 

this proposal and related rulemaking 

documents. 

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. Historical Certification Requirements 

Overview 

B. Aviation Rulemaking Committee (ARC) 

Recommendations 

C. Proposed Regulatory Requirements 

Overview 

II. Discussion of the Proposed Regulatory 

Requirements 

III. Regulatory Notices and Analyses 

IV. The Proposed Amendments 

I. Background 

A. Historical Certification Requirements 

Overview 

Title 14 Code of Federal Regulations 

(14 CFR) part 23 provides the 

airworthiness standards for Normal, 

Utility, Acrobatic, and Commuter 

Category Airplanes. The first 

application for the certification of a 

turbojet airplane under part 23 occurred 

in the 1970s before many of the current 

turbine requirements were added to part 

23. Prior to this, turbojet powered 

airplanes were certificated to the 

standards under part 25. Part 25 

provides the airworthiness standards for 

Transport category airplanes. A turbojet 

is a jet engine that develops thrust using 

a turbine compressor which is propelled 

by high speed exhaust gases expelled as 

a jet. The FAA implemented many of 

the certification requirements for early 

part 23 turbojets through special 

conditions based on 14 CFR part 25 

(pre-amendment 25–42, (43 FR 2320)) 

requirements. Almost all special 

conditions applied to turbojets were for 

part 23, subpart B, Flight, and subpart 

G, Operating Limitations and 

Information. 

Special conditions for part 23 

certification increased performance 

requirements for emerging turbojets 

similar to those covered by early part 25 

standards. The FAA established these 

special conditions to ensure a minimum 

one-engine inoperative (OEI) 

performance level that would be 

included in the airplane’s limitations, 

thereby guaranteeing single-engine 

climb performance. The level of safety 

provided by the special conditions was 

purposely higher for the early turbojets 

than for propeller-driven airplanes in 

the same weight band because the 

manufacturers and the FAA wanted part 

23 turbojets to be similar to part 25 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41523 

1 68 FR 5488 

business jets. Special conditions also 

addressed the following safety concerns: 

(1) The lack of turbine requirements in 

part 23, (2) the sensitivity of turbine 

engines to altitude and temperature 

effects, and (3) the high takeoff and 

landing speeds associated with turbojets 

that typically required long takeoff and 

landing distances, as compared to the 

performance of reciprocating, 

multiengine airplanes of that era. 

In the mid-1990s, the FAA hosted a 

meeting for flight test pilot 

representatives from the Aircraft 

Certification Offices. The purpose of 

that meeting was to discuss how 

emerging 600 to 1,200 pound thrust 

engines were being developed and how 

the FAA would certificate future 

turbojet programs. The participants 

considered the prospect for small singleand multi-engine turbojets. At that time, 

the FAA assumed that any new part 23 

turbojet would have similar 

characteristics to any existing small part 

25 turbojet. However, using the 

preliminary design estimates from 

several new turbojets, FAA flight test 

personnel realized these assumptions 

were outdated. Therefore, the FAA 

needed to reevaluate its certification 

standards for turbojets against existing 

light-weight airplanes. 

The meeting participants did not want 

to discourage development of small part 

23 turbojets by applying significantly 

higher standards than for an equivalent 

propeller airplane. Therefore, the 

participants decided the best approach 

for future turbojet certification programs 

was to apply the existing part 23 weight 

differentiator of 6,000 pounds in 

establishing requirements. 

B. Aviation Rulemaking Committee 

(ARC) Recommendations 

On February 3, 2003, we published a 

notice announcing the creation of the 

part 125/135 Aviation Rulemaking 

Committee.1 Part 125 addresses the 

certification and operations of airplanes 

having a seating capacity of 20 or more 

passengers or a maximum payload 

capacity of 6,000 pounds or more. Part 

135 addresses the operating 

requirements for commuter and ondemand operations and rules governing 

persons on board such aircraft. Since 

some part 23 airplanes operate under 

parts 125 or 135, the ARC provided 

recommendations to the FAA for safety 

standards applicable for part 23 turbojet 

airplanes to reflect the current industry, 

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. In addition, the ARC 

reviewed the special conditions applied 

to part 23 turbojets. The ARC completed 

its work in 2005 and submitted its 

recommendations to the FAA. Those 

documents may be reviewed in the 

docket for this proposed rule. The ARC 

recommended modifying forty-one 14 

CFR part 23 sections as a result of its 

review of these areas. 

As stated earlier, the FAA’s intent is 

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 above 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 pistonpowered and turboprop multiengine 

airplanes. The FAA ultimately accepted 

thirty-nine of the forty-one ARC 

recommendations and developed this 

proposed rulemaking in accordance 

with them. The two recommendations 

we disagreed with would have lowered 

the standards previously applied 

through special conditions. 

C. Proposed Regulatory Requirements 

Overview 

The FAA currently issues type 

certificates (TCs) to part 23 turbojets 

using extensive special conditions, 

exemptions, and equivalent levels of 

safety (ELOS). Until recently, this 

practice of using special conditions, 

exemptions, and ELOS did not represent 

a significant workload because there 

were relatively few part 23 turbojet 

programs. However, in the past five 

years, the number of new part 23 

turbojet type certification programs has 

increased more than 100 percent over 

the program numbers of the past three 

decades. The need to incorporate 

special conditions, exemptions, and 

ELOS into part 23 stems from this rise 

in the number of new turbojet programs 

and the expected growth in the number 

of future programs. Codifying special 

conditions would standardize and 

clarify the requirements for 

manufacturers during the design phase 

of turbojets. Doing so would prevent 

instances where manufacturers design 

turbojets and later have to demonstrate 

compliance with special conditions that 

may require redesign. Codifying special 

conditions, exemptions, and ELOS 

would also eliminate the manufacturers’ 

and the FAA’s workload associated with 

processing these documents and could 

reduce potential delays to project 

schedules. Many of the proposed 

changes in this notice would codify 

certification requirements and practices 

currently accomplished through use of 

special conditions, exemptions, and 

ELOS. 

We propose changes to part 1 

definitions to clarify new requirements 

proposed for part 23. In addition, we 

propose changes to part 23 in the areas 

of: 

• Airplane categories to allow 

commuter category certification of 

multiengine turbojets; 

• Flight requirements, including 

standards for performance, stability, 

stalls, and other flight characteristics; 

• Structure requirements, including 

standards for emergency landing 

conditions and fatigue evaluation; 

• Design and construction 

requirements, including standards for 

flutter, takeoff warning system, brakes, 

personnel and cargo accommodations, 

pressurization, and fire protection; 

• Powerplant requirements, including 

standards for engines, powerplant 

controls and accessories, and 

powerplant fire protection; 

• Equipment requirements, including 

general equipment standards and 

standards for instruments installation, 

electrical systems and equipment, and 

oxygen systems; and 

• Operating limitations and 

information, including standards for 

airspeed limitations, kinds of operation, 

markings and placards, and airplane 

flight manual and approved manual 

material. 

II. Discussion of the Proposed 

Regulatory Amendments 

1. Part 1: Definitions Clarifying Power 

and Engine Terms 

We propose to amend part 1 

definitions for ‘‘rated takeoff power,’’ 

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

‘‘turbojet engine,’’ and ‘‘turboprop 

engine.’’ Defining engine-specific terms 

would clarify the new requirements 

proposed for part 23. The need to define 

some of these terms was also shown by 

the following communications between 

the FAA and members of industry. 

These communications were based on 

the existing part 1 definitions for ‘‘rated 

takeoff power’’ and ‘‘rated takeoff 

thrust’’, which limit the use of these 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
41524 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

power and thrust ratings to no more 

than five minutes for takeoff operation. 

In 1990, the Airline Transport 

Association (ATA) sent a letter to the 

FAA asking the FAA to allow 10-minute 

OEI takeoff approval. At some airports 

(mostly foreign), the climb gradient 

capability needed to clear distant 

obstacles after takeoff requires more 

time at takeoff thrust than 5 minutes. 

Using only 5 minutes of takeoff thrust 

to clear distant obstacles limits the 

maximum allowable airplane takeoff 

weight. The availability of takeoff thrust 

or power for use up to 10 minutes, 

granted by some foreign authorities, 

enabled some foreign operators to 

dispatch at an increased gross weight 

over that allowed for U.S. operators. 

U.S. operators asked for equal treatment 

in similar circumstances. The FAA has 

approved these requests when they have 

been properly substantiated. This policy 

would also apply to operators of part 23 

turbojet-powered airplanes in order to 

achieve a climb gradient necessary to 

clear obstacles. 

2. Expanding Commuter Category to 

Include Turbojets 

Currently, we limit commuter 

category airplane requirements to 

propeller-driven, multiengine airplanes. 

The FAA has issued exemptions to 

allow turbojets weighing more than 

12,500 pounds to be certificated under 

part 23. The proposal to change § 23.3 

would codify the current FAA practice 

of certificating multiengine turbojets 

weighing up to and including 19,000 

pounds under part 23 in the commuter 

category. 

3. Performance, Flight Characteristics, 

and Other Design Considerations 

a. Performance 

We propose to extend the commuter 

category performance requirements to 

multiengine turbojets weighing more 

than 6,000 pounds. This proposal 

codifies requirements that we currently 

impose by special conditions for these 

airplanes. Amendment 23–45 (58 FR 

42136) requires all turbine-powered 

airplanes weighing 6,000 pounds or less 

to meet many of the same performance 

standards for reciprocating-powered 

airplanes weighing more than 6,000 

pounds. The FAA has determined that 

turbojets should meet a higher level of 

safety than reciprocating-powered 

airplanes in the same weight band. By 

requiring turbojets over 6,000 pounds to 

meet the higher commuter category 

certification requirements, the FAA 

would remain consistent in establishing 

more stringent requirements for turbojet 

airplanes than for reciprocating 

airplanes. 

The ARC recommended no changes to 

performance requirements in §§ 23.51, 

23.53, 23.55, 23.57, 23.59 and 23.61. 

The ARC pointed out that applying the 

commuter category takeoff performance 

requirements to multiengine turbojets 

weighing more than 6,000 pounds 

would include restrictions that could 

become a takeoff weight limitation for 

operations. The ARC stated that these 

requirements are too restrictive for part 

91 operations. However, existing 

multiengine turbojets weighing more 

than 6,000 pounds are required to meet 

these standards through special 

conditions, and we have seen negligible 

operational impact. We have no 

rationale or basis to support a reduced 

level of safety for part 23 turbojets. 

The ARC also reviewed FAA and 

Flight Safety Foundation accident 

studies for engine failure on takeoff. The 

ARC determined that existing normal 

category part 23 turboprops operated 

under part 135 have an acceptable safety 

record when compared to turbojets. 

Furthermore, turboprops in the accident 

studies were not certificated with any of 

the commuter category performance 

requirements for climb gradients. 

The ARC believed the safety record of 

the turboprops had more to do with the 

inherent reliability of turbine engines 

rather than the higher climb gradient. 

An ARC member suggested the higher 

OEI climb gradients originated in part 

25 during the large piston transport 

airplane engine era. Back then, the large 

piston engines were prone to failure on 

takeoff or initial climb, and the 

requirements for OEI climb gradients 

were necessary for safety. 

The ARC further believed raising the 

OEI climb performance requirements for 

most multiengine airplanes was 

appropriate. However, the ARC debated 

the appropriate OEI climb gradients for 

turbine-powered airplanes over 6,000 

pounds. Based on the reliability of 

turbine engines, the ARC only 

recommended raising the climb 

performance to 1 percent. This matched 

the ARC’s recommendation of 1 percent 

for turbojets under 6,000 pounds. The 

ARC’s recommendation, however, 

would reduce the OEI climb 

performance that is currently required 

through special conditions from 2 to 1 

percent for turbojet-powered airplanes 

over 6,000 pounds. 

Existing multiengine turbojets 

weighing more than 6,000 pounds are 

required through special conditions to 

meet the commuter category 

performance requirements (2 percent 

climb gradient) for OEI. We propose to 

maintain the 2 percent OEI climb 

gradient currently applied through 

special conditions for multiengine 

turbojets over 6,000 pounds. This climb 

gradient requirement is safe and 

prudent, and it is not reasonable to 

reduce the level of safety that already 

exists with part 23 turbojets. 

Although special conditions have 

required 2 percent OEI climb gradient 

for multiengine turbojets over 6,000 

pounds, there was no data to support 

whether small turbojets under 6,000 

pounds could meet the higher 2 percent 

climb gradient while maintaining 

reasonable utility. If our rule changes to 

§§ 23.63 and 23.67 negatively impacted 

their utility (i.e., weight-carrying 

ability), the rule might give the pistonpowered, multiengine airplanes a 

distinct market advantage. Accident 

studies show that turbojets are generally 

safer than piston-powered airplanes. 

Therefore, we wanted to compromise by 

proposing a requirement that would 

provide an adequate minimum safety 

standard and encourage production of 

more turbojets. One multiengine 

turbojet in this weight band has been 

operated as an air taxi, and the FAA 

expects this type of operation to grow. 

While this particular jet is capable of 

higher climb performance, we propose 

only to increase the OEI climb 

performance requirement to 1.2 percent 

because other jets in this weight band 

may not be capable of the higher 2 

percent climb performance. Based on 

accident data, 1.2 percent provides an 

adequate minimum safety standard. 

Historically, piston-powered, 

multiengine airplanes were allowed a 

lower climb requirement because they 

would not have any weight-carrying 

utility if forced to meet the same 

requirements of the larger airplanes. We 

are continuing this philosophy in this 

proposal. (See summary in the table 

below.) 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41525 

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

Multiengine type/airplane weight band Current rule 

ARC 

recommendation 

(percent) 

FAA proposal 

(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 

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

Turbojets >6,000 lbs. ................................................ 2.0 percent imposed through special conditions ..... 1.0 2.0

In addition to the proposed changes 

in takeoff and climb performance 

requirements described above, we also 

propose changes to other performance 

rules. Currently, part 23 reflects the 

traditional small airplane definition of 

landing configuration stall speed (VSO). 

However, certification personnel have 

interpreted VSO in part 23 as being the 

same as that in part 25. This 

interpretation has resulted in an 

unnecessary burden to the applicant. 

We are revising the part 23 requirement 

so that it is distinct from the part 25 

requirement and to retain the original 

definition of the term. We are proposing 

to revise paragraphs (a) and (c) of 

§ 23.49 to clarify the section. We are 

also proposing to correct the title of this 

section in the CFR to ‘‘Stalling speed’’ 

instead of ‘‘Stalling period.’’ 

VSO, by definition, is the stall speed 

in the maximum landing flap 

configuration and is not applicable to 

other flap configurations. (V speeds are 

defined in part 1. To simplify the 

understanding of the proposed rule, we 

are adding this information here.) 

Current § 23.73 references VSO. The 

reference to VSO in this paragraph is an 

error and should be changed to 

reference the stall speed for a specified 

flap configuration (VS1). The reference 

landing approach speed (VREF) should 

be based on 1.3 times the VS1. We 

propose to amend the standards to 

address airplanes certificated under part 

23 that may have more than one landing 

flap setting. We also propose to apply 

the commuter category requirements for 

VREF to multiengine turbojets over 6,000 

pounds maximum weight. In addition, 

we propose to apply the commuter 

category requirements for balked 

landings in § 23.77 to all multiengine 

turbine-powered airplanes over 6,000 

pounds, consistent with current special 

conditions for multiengine turbojets and 

turbine-powered airplanes over 6,000 

pounds. 

b. Flight Characteristics 

The FAA proposes to define 

‘‘maximum allowable speed’’ and to 

clarify the specific speed limitations, 

which include specific criteria for VFC, 

VLE, or VFC/MFC as appropriate. The 

proposal for § 23.177 would codify 

special conditions that include specific 

speed limitations. Furthermore, we are 

adding a new paragraph to § 23.175(b) to 

define the VFC/MFC (maximum speed for 

stability characteristics) term in part 23. 

This definition was inadvertently 

omitted in the last revision to part 23. 

The FAA proposes to amend the 

combined lateral-directional dynamic 

stability damping requirements for 

airplanes that operate above 18,000 feet. 

The existing stability damping 

requirements, which apply at all 

certificated altitudes, were developed 

when small airplanes typically operated 

under 18,000 feet and were not 

equipped with yaw dampers. The 

existing requirement remains 

appropriate for low altitude operations, 

such as for approaches, but it is not 

appropriate for larger airplanes that 

typically use yaw dampers and fly at 

altitudes well above 18,000 feet. The 

FAA has issued exemptions for most 

turbojets certificated under part 23 

because it is appropriate for highaltitude, high-speed operations. The 

proposed changes to § 23.181 would 

reduce the stability damping 

requirement at 18,000 feet and above. If 

adopted, this amendment would reduce 

the number of exemptions processed by 

the FAA by codifying what is allowed 

as an acceptable means of compliance. 

The FAA proposes to amend the 

existing stall requirements in §§ 23.201 

and 23.203 to include language from the 

turbojet special conditions. We propose 

clarifying the requirements for wingslevel and accelerated turning stalls. We 

also propose changing the roll-off 

requirements for wings-level, highaltitude stalls. 

The FAA proposes additional highspeed and high-altitude requirements to 

§§ 23.251 and 23.253 to address the new 

generation of high performance part 23 

airplanes. The FAA also proposes to 

extend provisions from part 25, 

§§ 25.251(d) and (e), to part 23. 

However, we would limit the 

requirements to airplanes that fly over 

25,000 feet and have a Mach dive speed 

(MD) faster than Mach 0.6 (M 0.6) to be 

consistent with part 25 requirements. 

The FAA also proposes the use of VDF/ 

MDF, which is demonstrated flight dive 

speed (VDF) or Mach (MDF) as referenced 

in the part 23 turbojet special 

conditions. 

Furthermore, we propose adding 

requirements in a new § 23.255 that 

would be based on § 25.255 and would 

address potential high-speed Mach 

effects for airplanes with MD greater 

than M 0.6. The FAA’s approach would 

only apply the part 25-based 

requirements to airplanes that 

incorporate a trimmable horizontal 

stabilizer, which is consistent with the 

ARC’s recommendation. The ARC’s 

recommendation was based on the 

positive service history with the existing 

fleet of part 23 and part 25 turbojets 

designed with conventional horizontal 

tails that use trimmable elevators. The 

industry manufacturers have designed 

airplanes that have experienced upset 

incidents involving out-of-trim 

conditions with a trimmable horizontal 

stabilizer. Service experience shows that 

out-of-trim conditions can occur in 

flight for various reasons, and the 

control and maneuvering characteristics 

of the airplane may be critical in 

recovering from upsets. The proposed 

language would require exploring the 

airplane’s high-speed control and 

maneuvering characteristics. 

c. Other Design Considerations 

We propose to revise language in 

§ 23.703 in the introductory text and 

paragraph (b) to add takeoff warning 

system requirements to all airplanes 

over 6,000 pounds and all turbojets. 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. 

We have proposed the commuter 

category, rejected takeoff requirements 

for all multiengine turbojets over 6,000 

pounds. The higher takeoff speeds and 

distances for these airplanes make the 

ability to stop in a specified distance a 

safety issue. Additional braking 

considerations accompany the rejected 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
41526 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

2 58 FR 38028. 

3 60 FR 65832 and 61 FR 2608. 

takeoff requirements. Therefore, we 

propose to apply the requirements for 

brakes in § 23.735 to all multiengine 

turbojets over 6,000 pounds, as well as 

to all commuter category airplanes. 

4. Structural Considerations for 

Crashworthiness and High-Altitude 

Operations 

The FAA proposes to codify into 

§ 23.561 the recent turbojet special 

conditions that were not available 

during the ARC’s effort. This proposal 

applies to single-engine turbojets with 

centerline engines embedded in the 

fuselage. Part 23 did not encompass 

embedded centerline engine 

installations, except for in-line 

propeller-pusher types. In light of 

several new turbojet designs, it is 

prudent to require greater engine 

retention strength for engines mounted 

aft of the cabin. This is especially true 

for engines mounted inside the fuselage 

behind the passengers. The proposed 

requirement would reduce the potential 

for the engine to separate from its 

mounts under forward-acting crash 

loads and subsequently intrude into the 

cabin. We recently applied this 

proposed requirement to a single-engine 

turbojet through special conditions. 

The ARC did not consider emergency 

landing dynamic conditions in § 23.562. 

We recognize, however, that § 23.562 

should be applicable to all turbojets, 

including those operating in the 

commuter category. All manufacturers 

of recently certificated commuter 

category turbojets have agreed to 

comply with § 23.562. The FAA 

proposes to amend § 23.562 to include 

all commuter category turbojets. This 

proposal would adopt current industry 

practice and ensure a consistent level of 

safety for all turbojets. 

At one time, the FAA proposed to 

apply the requirements for emergency 

landing dynamic conditions to all 

commuter category airplanes.2

Subsequently, we published new 

certification and operations 

requirements for commuter operations.3

These actions required certain 

commuter operators that previously 

conducted operations under part 135 to 

conduct those operations under part 

121. This rule, in effect, eliminated the 

use of new part 23 airplanes with 10 

seats or more in scheduled service. This 

action negated any projected benefits 

supporting the addition of emergency 

landing dynamic conditions to 

commuter category airplanes. 

The commuter operators affected were 

those conducting scheduled passengercarrying operations in airplanes that 

have passenger-seating configurations of 

10 to 30 seats (excluding any 

crewmember seat) and those conducting 

scheduled passenger-carrying 

operations in turbojet airplanes 

regardless of seating configuration. The 

action increased safety in scheduled 

passenger-carrying operations and 

clarified, updated, and consolidated the 

certification and operations 

requirements for persons who transport 

passengers or property by air for 

compensation or hire. 

In terms of overall configuration, 

commuter category turbojets have little 

resemblance to their propeller-driven 

counterparts. During an emergency 

landing, most commuter category 

turbojets will have more structure 

underneath the cabin floor available to 

absorb energy than traditional propellerdriven airplanes. This capability, along 

with the differences in the overall 

airplane configuration of turbojets, 

would suggest the test conditions 

specified in the current rule should be 

applicable to all turbojets. However, 

commuter category airplanes cannot 

exceed a maximum takeoff weight of 

19,000 pounds. With this limitation, the 

amount of crushable, energy absorbing 

structure is small when compared to 

most part 25 airplanes. For this reason, 

we propose to require the dynamic test 

conditions specified in part 23 rather 

than those in § 25.562. 

We also propose to modify the seating 

head injury criteria (HIC) calculation in 

the proposed rule to be consistent with 

the HIC definition in part 25. This 

proposal addresses the concern that the 

HIC definition in part 23 would lead to 

a HIC calculation only for the total time 

of the head impact, which would not 

necessarily maximize HIC. 

In the event of a ditching, the 

proposed change in § 23.807 would 

provide an alternative to meeting the 

current requirement for an emergency 

exit, above the waterline, on both sides 

of the cabin for multiengine airplanes. 

Proposed section 23.807 would allow 

the placement of a water barrier in the 

doorway before the door would be 

opened as a means to comply with the 

above waterline exit requirement. This 

barrier would be used to slow the inflow 

of water. The FAA has approved the use 

of this barrier as an alternative to the 

above waterline exit for several 

airplanes by issuing an ELOS finding. 

Several new part 23 turbojet programs 

include approval for operations at 

altitudes above 40,000 feet. 

Additionally, the FAA has issued 

special conditions for operations up to 

49,000 feet. We propose rule changes for 

structures and the cabin environment to 

ensure structural integrity of the 

airplane at higher altitudes. We also 

propose 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. 

We propose to amend § 23.831 to add 

new paragraphs (c) and (d), which 

include standards appropriate for 

airplanes operating at high altitudes 

beyond those included in part 23. The 

proposed changes are intended to 

ensure flight deck and cabin 

environments do not result in the crew’s 

mental errors or physical exhaustion 

that would prevent the crew from 

successfully completing assigned tasks 

for continued safe flight and landing. 

An applicant may demonstrate 

compliance with paragraph (d) of this 

requirement if the applicant can show 

that the flight deck crew’s performance 

is not degraded. 

The cabin environment must be 

conservatively specified such that no 

occupant would incur any permanent 

physiological harm after 

depressurization. The environmental 

and physiological performance limits 

used for demonstrating compliance 

must originate from recognized and 

cognizant authorities as accepted by the 

regulatory authority reviewing the 

compliance finding. 

As part of the certification process, we 

would consider the entire flight profile 

of the airplane during the 

depressurization event. The profile 

would include cruise and transient 

conditions during descent, approach, 

landing, and rollout to a stop on the 

runway. We would not include taxiing 

as a compliance consideration because 

the airplane would be on the ground 

and could be evacuated, or flight deck 

windows and cabin doors could be 

opened for ventilation. The condition of 

the airplane from the beginning of the 

event to the end of the landing roll is 

accounted for when assessing the safe 

exit of an airplane. 

We chose the words ‘‘* * * shall not 

adversely affect crew performance 

* * *’’ to mean the crew can be 

expected to reliably perform either their 

published or trained duties, or both, to 

complete a safe flight and landing. We 

have measured this in the past by a 

person’s ability to track and perform 

tasks. The event should not result in 

expecting the crew to perform tasks 

beyond the procedures defined by the 

manufacturer or required by existing 

regulations. We use the phrase ‘‘No 

occupant shall sustain permanent 

physiological harm’’ to mean the 

occupants who may have required some 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41527 

form of assistance, once treated, must be 

expected to return to their normal 

activities. 

To show compliance to the proposed 

rule, the applicant should consider what 

would happen to the airplane and 

systems during depressurization. The 

applicant may also consider operational 

provisions, which provide for or 

mitigate the resulting environmental 

effects to airplane occupants. If the 

manufacturer provides an approved 

procedure(s) for depressurization, the 

flight deck and cabin crew may 

configure the airplane to moderate 

either temperature or humidity 

extremes, or both, on the flight deck and 

in the cabin. This configuration may 

include turning off non-critical 

electrical equipment and opening the 

flight deck door, or opening the flight 

deck window(s). 

As with § 23.831, we find it necessary 

to amend the standards 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 intent of the proposed changes to 

§ 23.841 is to provide airworthiness 

standards that allow subsonic, 

pressurized turbojets 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 would 

be protected from the effects of hypoxia 

(i.e., deprivation of adequate oxygen 

supply), and (3) if some occupants do 

not receive supplemental oxygen, they 

would be protected against permanent 

physiological harm. 

Existing rules require the cabin 

pressure control system maintain the 

cabin at an altitude of not more than 

15,000 feet if any probable failure or 

malfunction in the pressurization 

system occurs. 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. We have 

granted ELOS findings for this 

characteristic because physiological 

data shows the brief duration of the 

overshoot would have no significant 

effect on an airplane’s occupants. 

Special conditions issued for part 23 

turbojets are similar and, for operating 

altitudes above 41,000 feet, equivalent 

to the requirements in § 25.841 adopted 

in Amendment 25–87 (61 FR 28684). 

That amendment revised § 25.841(a) to 

include requirements for pressurized 

cabins that were previously covered 

only in special conditions. The special 

conditions required consideration of 

specific failures. The FAA incorporated 

reliability, probability, and damage 

tolerance concepts addressing other 

failures and methods of analysis into 

part 25 after the issuance of the special 

conditions. Sections 23.571, 23.573, and 

23.574 address damage tolerance 

requirements. We propose to require the 

use of these additional methods of 

analysis as part of this rulemaking. 

This proposal also specifies a more 

performance-based criterion, such that 

failures cannot adversely affect crew 

performance nor result in permanent 

physiological harm to passengers. 

(Note: There is a different standard for the 

crew than the passengers.) 

Part 23 requires a warning of an 

excessive cabin altitude at 10,000 feet. 

Those regulations do not adequately 

address airfield operation above 10,000 

feet. Rather than disable the cabin 

altitude warning to prevent nuisance 

warnings, we have issued ELOS 

findings that allow the warning altitude 

setting to be shifted above the maximum 

approved field elevation, not to exceed 

15,000 feet. We propose to revise 

§ 23.841 to incorporate language from 

existing ELOSs into the regulation. 

Currently, we address oxygen systems 

for airplanes operating above 41,000 feet 

using special conditions derived from 

part 25. A large number of new turbojets 

and high-performance airplanes 

entering part 23 certification will 

operate at higher altitudes than 

previously envisioned for part 23 

airplanes. We are proposing revisions to 

§§ 23.1443, 23.1445, and 23.1447 to 

establish requirements for oxygen 

systems. These new requirements would 

eliminate the need for special 

conditions for airplanes operating above 

40,000 feet. 

5. General Fire Protection and 

Flammability Standards for Insulation 

Materials 

When we initially introduced 

powerplant fire protection provisions in 

part 23, we did not foresee turbojet 

engines embedded in the fuselage, nor 

in pylons on the aft fuselage, for 

airplanes certificated to part 23 

standards. We propose to add fire 

protection requirements for turbojets in 

§§ 23.1193, 23.1195, 23.1197, 23.1199, 

and 23.1201. Part 23 has historically 

addressed fire protection through 

prevention, identification, and 

containment. Manufacturers have 

provided prevention through 

minimizing the potential for ignition of 

flammable fluids and vapors. Also 

historically, pilots had been able to see 

the engines and identify the fire or use 

the incorporated fire detection systems, 

or both. The ability to see the engine 

provided for the rapid detection of a 

fire, which led to a fire 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. 

Isolating designated fire zones, 

through flammable fluid shutoff valves 

and firewalls, provides for containment 

of a fire. Containing fires ensures that 

components of the engine control 

system function effectively to permit a 

safe shutdown of the engine. We have 

only required a demonstration of 

containment for 15 minutes. If a fire 

occurs in a traditional part 23 airplane, 

the corrective action is to land as soon 

as possible. For a small, simple airplane 

originally envisioned by part 23, it is 

possible to descend the airplane to a 

suitable landing site within 15 minutes. 

If the isolation means do not extinguish 

the fire, the occupants can safely exit 

the airplane before the fire breaches the 

firewall. 

Simple and traditional airplanes 

normally have the engine located away 

from critical flight control systems and 

the primary structure. This location has 

ensured that throughout the fire event, 

the pilot can continue safe flight and 

control of the airplane and predict the 

effects of a fire. Other design features of 

simple and traditional airplanes (e.g., 

low stall speeds and short landing 

distances) ensure that even if an offfield landing occurs, the potential for a 

catastrophic outcome is minimized. 

Specifically for airplanes equipped 

with embedded engines, the 

consequences of a fire in an engine 

embedded in the fuselage are more 

varied, adverse, and difficult to predict 

than the engine fire for a typical part 23 

airplane. Engine(s) embedded in the 

fuselage offer minimal opportunity to 

actually see a fire. The ability to 

extinguish an engine fire becomes 

extremely critical due to this location. 

With the engine(s) embedded in the 

fuselage, an engine fire could affect both 

the airplane’s fuselage and the 

empennage structure, which includes 

the pitch and yaw controls. A sustained 

fire could result in damage to this 

primary structure and loss of airplane 

control before a pilot could make an 

emergency landing. For embedded 

engine installations, we also propose 

requiring a two-shot fire-extinguishing 

system because the metallic components 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
41528 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

4Under the proposed changes, we would 

certificate new engines, which include electronic 

ignition systems and engines with electronic 

controls necessary for the engine’s operation, 

through the Engine and Propeller Directorate. 

in the fire zone can become hot enough 

to reignite flammable fumes after 

someone extinguishes the first fire. 

We propose to upgrade flammability 

standards for thermal and acoustic 

insulation materials used in part 23 

airplanes. The current standards do not 

realistically address situations where 

thermal or acoustic insulation materials 

may contribute to propagating a fire. 

The changes we propose are based on 

the requirements in § 25.856(a), which 

were adopted following accidents 

involving part 25 airplanes, such as the 

Swissair MD–11. We believe the 

proposed 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. 

The proposed standards include new 

flammability tests and criteria that 

address flame propagation, which 

would apply to thermal/acoustic 

insulation material installed in the 

fuselage of part 23 airplanes. 

Certification tests would consist of 

samples of thermal/acoustic insulation 

that would be exposed to a radiant heat 

source and a propane burner flame for 

15 seconds. The insulation must not 

propagate flame more than 2 inches 

away from the burner. The flame time 

after removal of the burner must not 

exceed 3 seconds on any specimen. (See 

proposed Part II, Appendix F to part 23 

for more details.) 

Current flammability requirements 

focus almost exclusively on materials 

located in occupied compartments 

(§ 23.853) and cargo 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/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. Proposed 

§ 23.856 would be 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, dated April 2000. 

A copy of the handbook has been placed 

in the docket for this rulemaking. 

Insulation is usually constructed in 

what is commonly referred to as a 

‘‘blanket.’’ Insulation blankets typically 

consist of two things: (1) A batting of a 

material generically referred to as 

fiberglass (i.e., glass fiber or glass wool), 

and (2) a film covering to contain the 

batting and to resist moisture 

penetration, usually metalized or nonmetalized polyethylene terephthalate 

(PET), or metalized polyvinyl fluoride 

(PVF). Polyimide, a heat-resistant fiber 

used in insulation and adhesive, is 

another film used on certain airplanes. 

Regardless of the film type used, there 

are variations associated with its 

assembly for manufacture that result in 

performance differences from a fire 

safety standpoint. These variations 

include the density of the film, the type 

and fineness of the scrim bonded to the 

film, and the adhesive used to bond the 

scrim to the film. The scrim resembles 

a screen, and the mesh can vary in 

fineness. The scrim is usually 

constructed of either nylon or polyester 

and is bonded to the backside of the 

film to add shape and strength to the 

surface area. The adhesive used to bond 

the scrim to the film also varies. 

However, the type of adhesive used is 

important because fire retardant is 

frequently concentrated in the adhesive 

of the assembled sheet. 

6. Powerplant and Operational 

Considerations 

Current § 23.777 standardizes the 

height and location of powerplant 

controls because pilots may become 

confused and use the wrong controls on 

propeller-driven airplanes. This 

requirement, however, does not include 

single-power levers (which are typical 

for electronically-controlled engines). 

The FAA currently makes an ELOS 

finding for each airplane program that 

includes a single-power lever. We 

propose to revise paragraph (d) in 

§ 23.777 to incorporate the ELOS 

language. 

We propose to revise § 23.903, 

paragraph (b)(2), to add requirements for 

fuselage-embedded, turbofan engine 

installations. These types of engine 

installations may have a negative impact 

on passenger safety because passengers 

occupy an area directly ahead of the 

turbojet engine fan disk. Certain 

turbofan engine designs have failure 

conditions that allow the fan disk to exit 

the front of the engine. This failure 

condition occurs if engines have 

bearing/shaft configurations that would 

allow the disk to separate from the 

engine and travel forward. If the engine 

has demonstrated this failure mode or if 

an analysis shows such a failure is 

conceivable, then the requirements of 

this section would apply. This 

requirement would be applicable to 

engines embedded in the airplane’s 

fuselage where it could move forward 

into areas occupied by passengers or 

crew when a disk fails. 

In addition to the changes described 

above, we also propose requiring that 

electronic engine control systems meet 

the equipment, systems, and installation 

standards of § 23.1309. We have applied 

this requirement to all digital engine 

controls in part 23 airplanes by special 

condition. The proposed rule change for 

§ 23.1141 would largely eliminate the 

need to issue special conditions on 

future certification programs. 

The ARC believed few single-engine 

airplane manufacturers have analyzed 

the criticality of their control system to 

meet the requirements of this proposed 

rule. The fundamental rule change 

recommended by the ARC for § 23.1141 

was not intended to invalidate or 

overrule the 14 CFR part 33 certification 

requirements. The proposed change for 

§ 23.1141 is intended for consideration 

of the airframe/engine interface and 

how that interface protects against high 

intensity radiated fields (HIRF) and 

lightning. 

Over the years, airplane engines, 

including turbines, generated their own 

ignition system electrical power 

separate from the airplane’s electrical 

generation system. Even with a 

complete electrical failure of the 

primary electrical systems, the engines 

would still run and be fully functional. 

However, all new engines are not 

designed with self-electrical-generation 

capability. Some new engines rely on 

the airplane’s electrical system to 

continue running and to be fully 

functional. Revising § 23.1165(f) would 

ensure that when approved engines are 

installed on part 23 airframes, the 

engine ignition system is identified as 

an essential load. This would ensure 

that those engines have power during 

emergencies.4

7. Avionics, Systems, and Equipment 

Changes 

Updated system requirements should 

reduce the regulatory burden on the 

applicant by clarifying and expanding 

the applicability of §§ 23.1301 and 

23.1309 to specific systems and 

functions. Most new part 23 airplane 

manufacturers are installing electronic 

primary flight displays (PFD) and 

multifunction displays (MFD) that 

replace conventional electromechanical 

and mechanical instruments. These new 

systems also offer more capability, 

reliability, and features that improve 

safety. 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41529 

5A copy of the advisory circular is available on 

the Internet at http://www.faa.gov/ 

regulations_policies/. 

We propose changes that would 

address displays, software, hardware, 

and power requirements. Besides 

advanced avionics and integrated 

systems, we propose to update the 

certification requirements to consider 

other advanced technologies (e.g., 

digital engine controls). We intend to 

apply lessons learned from recent small 

turbojet certification programs to update 

requirements for intended function and 

system safety. 

The ARC did not make a specific 

recommendation for § 23.1301. 

However, the FAA seeks to clarify the 

intent of this section because it is 

frequently misinterpreted and 

misapplied. Clarifying the intent of 

§ 23.1301 would improve 

standardization for systems and 

equipment certification, particularly for 

non-required equipment and nonessential functions embedded within 

complex avionic systems. Our intent is 

for the applicant to define proper 

functionality and to propose a means of 

compliance acceptable to the 

Administrator. We expect applicants to 

coordinate or negotiate deviations from 

established means of compliance with 

the Administrator as early as possible to 

minimize delay to project schedules. 

We propose to remove § 23.1301(d), 

which currently states that equipment 

must ‘‘function properly when 

installed.’’ The proposed change would 

limit the scope of the rule since it would 

apply only to equipment required for 

type certification or operation. We 

propose a related change to clarify 

similar language in § 23.1309 for proper 

functionality of installed equipment. 

The ARC did not make a specific 

recommendation for § 23.1303. 

However, the FAA seeks to clarify the 

intent of this rule to accommodate new 

technology and eliminate the need to 

issue an ELOS for part 23 airplanes. We 

propose to amend § 23.1303(c) by 

changing the current requirement from 

‘‘A direction indicator (non-stabilized 

magnetic compass)’’ to ‘‘A magnetic 

direction indicator.’’ Section 23.1303 

does not include a direction indicator, 

other than the typical non-stabilized 

compass for part 23 airplanes. As new 

technology becomes more affordable for 

part 23 airplanes, many electronic flight 

instrument systems will use 

magnetically stabilized direction 

indicators (or electric compass systems) 

to measure and indicate the airplane 

heading to provide better performance. 

Current regulations require 

powerplant displays, referred to as 

‘‘indicators’’ in § 23.1305, to provide 

trend or rate-of-change information. 

Advisory Circular (AC) 23.1311–1B, 

Installation of Electronic Displays in 

Part 23 Airplanes, dated June 14, 2005, 

currently provides a basis for an ELOS 

finding for digital engine display 

parameters.5 The proposed rule changes 

to §§ 23.1303, 23.1305, and 23.1311 

would largely eliminate the need to 

issue ELOS findings for these systems 

and help standardize certification of 

new technology. 

The ARC also did not make a specific 

recommendation for § 23.1307. 

However, the FAA seeks to clarify 

language so applicants understand they 

may need additional equipment to 

operate their airplane. Part 23 is a 

minimum performance standard, and it 

may not include all the required 

equipment for commercial operations 

under 14 CFR part 135. We propose to 

include parts 91 and 135 operations as 

examples to use when deciding which 

equipment is necessary for an airplane 

to operate at the maximum altitude. 

a. System SafetyAssessment 

Requirements 

We originally designed the system 

safety assessment requirements of 

§ 23.1309 to address certification of 

electronic systems driven by 

microprocessors and other complex 

systems. However, the requirements of 

§ 23.1309 are being applied to 

conventional mechanical and 

electromechanical systems with wellestablished design and certification 

processes. This was not our intent, and 

we propose to revise § 23.1309 to clarify 

the intended application of the rule. 

Proposed changes for § 23.1309 also 

clarify the intent for certification of 

electronic engine controls. The current 

section excludes systems certificated 

with the engine. Therefore, we use 

special conditions for all electronic 

engine control installation approvals to 

capture the evaluation requirements of 

§ 23.1309. We applied special 

conditions to the interface of the 

electronic engine control system and the 

airplane. We also applied special 

conditions to verify that the installation 

does not invalidate the assumptions 

made during part 33 certification of the 

engine. This proposal would address 

electronic engine controls and eliminate 

the need for special conditions to apply 

§ 23.1309 to electronic engine control 

systems. 

Proposed § 23.1309(a) would have 

requirements for two different types of 

equipment and systems installed in the 

airplane. Proposed § 23.1309(a)(1) 

would cover the equipment and systems 

that have no negative safety effect and 

those installed to meet a regulatory 

requirement. Such systems and 

equipment are required to ‘‘perform as 

intended under the airplane operating 

and environmental conditions.’’ 

Proposed § 23.1309(a)(2) would require 

the applicant to show that all equipment 

and systems (including approved 

‘‘amenities,’’ such as a coffee pot and 

entertainment systems) have no safety 

effect on the operation of the airplane. 

The phrase ‘‘improper functioning’’ 

identifies equipment and system 

failures that have a potentially negative 

effect on airplane safety. Therefore, we 

must consider their potential failure 

condition(s). Using § 23.1309, we must 

analyze any installed equipment or 

system that has potential failure 

condition(s) that are catastrophic, 

hazardous, major, or minor to determine 

their impact on the safe operation of the 

airplane. 

We propose to clarify the certification 

requirements, environmental 

qualification test requirements, and our 

intent for determining proper ‘‘intended 

function’’ of non-required systems and 

equipment that do not have a safety 

effect on the airplane. A problem with 

the current requirements for airplane 

manufacturers arises when certification 

authorities question installation of nonrequired systems and equipment that do 

not perform following their 

specifications and, therefore, are ‘‘not 

functioning properly when installed.’’ 

Usually, normal installation practices 

can be based on a relatively simple 

qualitative installation evaluation. If the 

possible safety impacts (including 

failure modes or effects) are 

questionable, or isolation between 

systems is provided by complex means, 

more formal structured evaluation 

methods or a design change may be 

necessary. We do not require these types 

of equipment and systems to function 

properly when installed. However, we 

would require them to function when 

they are tested to verify that they do not 

interfere with the operation of other 

airplane equipment and systems and do 

not pose a hazard in and of themselves. 

Also under proposed changes to 

§ 23.1309(a), we would replace the 

conditional qualifiers of ‘‘under any 

foreseeable operating condition,’’ 

contained in the current § 23.1309(b)(1), 

with ‘‘under the airplane operating and 

environmental conditions.’’ Our intent 

with this proposal is for the applicant to 

take two actions. First, the applicant 

must consider the full normal operating 

envelope of the airplane, as defined by 

the airplane flight manual (AFM), with 

any modification to that envelope 

associated with abnormal or emergency 

procedures and any anticipated crew 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
41530 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

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.’’ We propose to make this 

change in response to an observation 

that although certain operating 

conditions are foreseeable, achieving 

normal performance when they exist is 

not always possible (e.g., you may 

foresee ash clouds from volcanic 

eruptions, but airplanes with current 

technology cannot safely fly in such 

clouds). 

The FAA currently accepts equipment 

that is susceptible to failures if these 

failures do not contribute significantly 

to the existing risks (e.g., some 

degradation in functionality and 

capability is routinely allowed during 

some environmental qualifications, such 

as HIRF and lightning testing). System 

lightning protection specifically allows 

the loss of function and capability of 

some electrical/electronic systems when 

the airplane is exposed to lightning, if 

‘‘these functions can be recovered in a 

timely manner.’’ 

Proposed § 23.1309(a)(3) is applicable 

for all functional reliability, flight 

testing, or flight evaluations. This 

proposed change clarifies the FAA’s 

expectations for functional testing 

during certification of complex systems, 

but it is not meant to increase the testing 

burden on the applicant. The FAA’s 

intent is to prohibit certification of 

systems with known defects in required 

functions that could impact safety. For 

example, it would not be acceptable for 

an integrated avionics system to be 

approved until known functional 

defects in required functions are 

corrected. The system would not be 

allowed to exhibit unintended or 

improper functionality for flight critical 

functions. The rate of occurrence of 

failures, malfunctions, and design errors 

must be appropriate for the failure 

condition(s) of the type of system and 

airplane. 

Proposed § 23.1309(b) would codify a 

long-established means of compliance 

with current § 23.1309(b) and update 

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)). 

This means of compliance identifies 

four classes of airplanes as defined in 

Appendix K of this proposal and applies 

appropriate probability values and 

development assurance levels for each 

class. The original text of § 23.1309(b)(4) 

has been retained and appears as 

§ 23.1309(b)(5) in this revision. The 

proposed changes to § 23.1309(c) and 

(d) are meant to define the proper scope 

and intent for applying § 23.1309 depth 

of analysis for system safety assessments 

to all systems. 

With proposed § 23.1309(f), we would 

make § 23.1309 compatible with the 

current § 23.1322 (‘‘Warning, caution, 

and advisory lights’’) that distinguishes 

between caution, warning, and advisory 

lights installed on the flight deck. 

Rather than only providing a warning to 

the flight crew, which is required by the 

current rule, proposed § 23.1309(f) 

would require that information 

concerning an unsafe system operating 

condition(s) be provided to the flight 

crew. 

A warning indication would still be 

required if immediate action by a flight 

crewmember were required. The 

particular method of indication would 

depend on the urgency and need for 

flight crew awareness or action that is 

necessary for the particular failure. 

Inherent airplane characteristics may be 

used in lieu of dedicated indications 

and annunciations that can be shown to 

be timely and effective. The use of 

periodic maintenance or flight crew 

checks to detect significant latent 

failures when they occur should not be 

used in lieu of practical and reliable 

failure monitoring and indications. 

Proposed § 23.1309(f) would clarify 

the current rule by specifying 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 

would be those that are caused by 

inappropriate actions made by a 

crewmember in response to the failure, 

or those that could occur after a failure. 

Any procedures for the flight crew to 

follow after the occurrence of a failure 

indication or annunciation would be 

described in the approved Airplane 

Flight Manual (AFM), AFM revision, or 

AFM supplement, unless they are 

accepted as part of normal aviation 

abilities. 

Current § 23.1309 (c) and (d) are not 

directly related to the other safety and 

analysis requirements of § 23.1309. The 

ARC considered it appropriate to state 

the requirements separately for clarity. 

We agree with this suggested change 

and propose to add a new § 23.1310 to 

accommodate the change. The 

requirements as originally stated in 

current § 23.1309 would not change, 

except for a new section number. 

We propose several changes to 

§ 23.1311(a)(5) for plain language 

purposes. In proposed § 23.1311(a)(5), 

we replace the phrase ‘‘individual 

electronic display indicators’’ with 

‘‘electronic display parameters.’’ The 

term ‘‘indicator’’ has a long-standing 

definition based on conventional, 

mechanical indicators; therefore, the 

term has caused confusion. These 

electronic display parameters could be 

integrated on one electronic display that 

is independent of the primary flight 

display. In proposed § 23.1311(a)(6), we 

add the phrase ‘‘that provide a quickglance sense of rate and, when 

appropriate, trend information’’ to 

clarify ‘‘sensory cues.’’ 

We propose to add the term ‘‘when 

appropriate’’ to eliminate the 

requirement to display trend 

information when it would otherwise 

provide intuitive information to the 

pilot. For example, the trend for fuel 

burn is always negative. We propose to 

remove the remainder of section (a)(6), 

‘‘* * * that are equivalent to those in 

the instrument being replaced by the 

electronic display indicator’’ to prevent 

confusion since most instruments will 

be electronic. In proposed 

§ 23.1311(a)(7), we have added the word 

‘‘equivalent’’ to make acceptable 

instrument markings on electronic 

displays that are equivalent to those 

instrument markings on conventional 

mechanical and electromechanical 

instruments. 

In proposed § 23.1311(b), we replace 

the phrase ‘‘remain available to the 

crew, without need for immediate 

action’’ with ‘‘be available within one 

second to the crew with a single pilot 

action or by automatic means.’’ The 

proposed language allows an applicant 

to take credit for reversionary or 

secondary flight displays on a multifunction flight display (MFD) that 

provides a secondary means of primary 

flight information (PFI). This is 

acceptable if the display can ‘‘be 

available within one second to the crew 

with a single pilot action or by 

automatic means.’’ MFD’s may also 

display PFI as needed to ensure 

continuity of operations. The display of 

PFI on reversionary (secondary) 

displays must be arranged in the basic 

T-configuration. Also, such displays 

must be legible and usable from the 

pilot’s position with minimal head 

movement to meet the requirements of 

§ 23.1321. 

There are three acceptable methods 

for meeting the requirements of 

§ 23.1311(b)—(1) Dedicated standby 

instruments, (2) dual primary flight 

displays (PFDs), or (3) reversionary 

displays that display independent 

attitude. The standby instruments, or 

another independent PFD, would ensure 

that primary flight information is 

available to the pilot during all phases 

of flight and system failures. The 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41531 

electronic display systems with dual 

PFDs should incorporate dual, 

independently-powered sensors that 

would provide primary flight 

parameters (e.g., attitude heading 

reference system (AHRS) with 

comparators and dual air data computer 

(ADC)). A reversionary configuration 

would have a single pilot action that 

would force MFD displays into 

reversionary mode operation by a single 

pilot action within one second or less. 

However, the PFI must be displayed in 

substantially the same format and size 

in the reversionary mode as it is in 

normal mode. The single pilot action 

should be easily recognized, readily 

accessible, and have the control within 

the pilot’s primary field of view. 

The reversionary method could 

include an automatic reversionary 

display with a single pilot action. If PFI 

on another display is not provided, we 

would require automatic switching to 

ensure PFI is available to the pilot. This 

automatic reversionary capability would 

cover most possible malfunctions. 

While a total loss of the display may not 

be reliably detected automatically, such 

a failure condition would be obvious to 

the pilot. Malfunctions that result in 

automatic switching would be extensive 

enough to ensure PFI is available at the 

reliability level required by § 23.1309. If 

such a malfunction occurs, a single pilot 

action would provide a full display of 

the essential information on the 

remaining display within one second. 

All modes, sources, frequencies, and 

flight plan data would be exactly as they 

were on the PFD before the failure. 

Another reversionary method would 

include a means to access the 

reversionary mode manually through a 

single pilot action. Manual activation of 

the reversionary mode on the MFD 

through single action by the pilot would 

be acceptable when procedures to 

activate the PFI are accomplished before 

entering critical phases of flight. The 

PFI would display continuously on the 

reversionary display during critical 

phases of flight (e.g., takeoff, landing, 

and missed or final approach). 

To meet the proposed turbojet 

performance requirements in subpart B, 

the pilot would need accurate speed 

indicators while accelerating on the 

runway. We propose to revise 

§ 23.1323(e) to add the requirement to 

calibrate the airspeed system down to 

0.8 of the minimum value of V1. Also, 

we propose to adopt the language used 

in part 25 for this same requirement 

because it is more in line with operating 

new part 23 turbojets. 

The proposed changes to § 23.1331 

would apply to instruments that rely on 

a power source to provide required 

flight information for instrument flight 

rules (IFR) operations. Consequently, 

this section would apply to all flight 

instruments, such as those required by 

parts 23, 91, 121, and 135. Airplanes 

limited by type design to visual flight 

rules (VFR) operations would not have 

to comply with the requirements of 

proposed § 23.1331(c). 

Each independent power source must 

provide sufficient power for normal 

operations throughout the approved 

flight envelope of the airplane and for 

any operations approved for the 

airplane. Section 23.1331(c) would not 

require the installation of dual 

alternators or vacuum systems on 

single-engine airplanes. One option 

would include a dedicated battery that 

meets the requirements of § 23.1353(h) 

for electrical instrument loads essential 

to continued safe flight and landing. 

Another option would include 

separately powered instruments for 

primary and standby use. The last 

option would include performing a 

system safety analysis, per § 23.1309, to 

identify the procedures necessary to 

verify the charge state of any airplane 

starting battery that is used to power a 

stand-by system. 

The ARC did not make a specific 

recommendation for § 23.1353. 

However, we propose to add additional 

battery endurance requirements 

depending on the airplane’s altitude 

performance. Proposed § 23.1353 

addresses the power needs of new allelectrical instruments, navigation and 

communications equipment, and engine 

controls. 

When § 23.1353(h) was adopted, part 

23 airplanes were mostly mechanical. 

We did not envision all-electric, or 

almost all-electric, airplanes. Current 

§ 23.1353(h) requires 30 minutes of 

sufficient electrical power for a reduced 

or emergency group of equipment and 

instrumentation. We 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. We did not envision 

integrated electric cockpits when we 

developed § 23.1353(h). New part 23 

airplanes are being certificated with allelectrical instruments, including the 

standby instruments. This reliance on 

electric power increases the importance 

of ensuring adequate battery power until 

the pilot can descend and make a safe 

landing. 

Most new engines utilize electronic 

engine controls. These engine controls 

may rely on the airplane’s electrical 

system for power and to control fuel and 

ignition. Large engines typically 

installed on part 25 airplanes have a 

dedicated power source running off the 

engine; as long as the engine is running, 

the electronic engine control has power. 

Some of the smaller, simpler engines 

emerging in part 23 airplanes may not 

have these dedicated power sources and 

may rely on the airplane’s electrical 

system to keep functioning. 

We believe that most new turbinepowered airplanes, and some 

turbocharged, piston-powered airplanes, 

will operate at high altitudes under IFR. 

Under these conditions, 30 minutes may 

not be adequate for battery power 

because of the time it would take 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, proposed § 23.1353(h) would 

extend the battery time requirement to 

60 minutes for airplanes approved with 

a maximum altitude above 25,000 feet. 

Many new single-engine airplanes are 

intended for use in part 135 passenger 

service. Proposed § 23.1353(h) provides 

consistency with the operating 

requirements for single-engine IFR in 

§ 135.163(i). That section requires a 60- 

minute battery to power all emergency 

equipment, as specified by the 

manufacturer, to allow continued safe 

flight and landing. 

b. Allowable Qualitative Failure 

Condition Probabilities 

We propose to add Appendix K to 

show the appropriate airplane systems 

probability standards, failure 

conditions, and related development 

assurance for four certification classes of 

airplanes designed to part 23 standards. 

Proposed Appendix K includes 

development assurance levels that 

correlate to the software levels in RTCA/ 

DO–178B and the complex design 

assurance levels in RTCA/DO–254. We 

provided quantitative values in 

Appendix K to indicate the order of 

probability range for each certification 

class and failure condition. 

As used in § 23.1309, the FAA 

proposes the following definitions for 

terms used in Appendix K: 

i. Extremely remote failure conditions: 

Those failure conditions not anticipated 

to occur to each airplane during its total 

life but which may occur a few times 

when considering the total operational 

life of all airplanes of this type. For 

quantitative assessments, refer to the 

probability values shown for hazardous 

failure conditions in Appendix K. 

ii. Extremely improbable failure 

conditions: For commuter category 

airplanes, those failure conditions so 

unlikely that they are not anticipated to 

occur during the entire operational life 

of all airplanes of one type. For other 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
41532 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

classes of airplanes, the likelihood of 

occurrence may be greater. For 

quantitative assessments, refer to the 

probability values shown for 

catastrophic failure conditions in 

Appendix K. 

iii. Probable failure conditions: Those 

failure conditions anticipated to occur 

one or more times during the entire 

operational life of each airplane. These 

failure conditions may be determined 

on the basis of past service experience 

with similar components in comparable 

airplane applications. For quantitative 

assessments, refer to the probability 

values shown for minor failure 

conditions in Appendix K. 

iv. Remote failure conditions: Those 

failure conditions that are unlikely to 

occur to each airplane during its total 

life but that may occur several times 

when considering the total operational 

life of a number of airplanes of this type. 

For quantitative assessments, refer to 

the probability values shown for major 

failure conditions in Appendix K. 

v. Design appraisal: A qualitative 

appraisal of the integrity and safety of 

the system design. An effective 

appraisal requires experienced 

judgment. 

vi. Development assurance level: All 

planned and systematic actions used to 

substantiate, to an adequate level of 

confidence, that errors in requirements, 

design, and implementation have been 

identified and corrected such that the 

system satisfies the applicable 

certification basis. (The development 

assurance levels in Appendix K are 

intended to correlate to software levels 

in RTCA/DO–178B and complex 

hardware design assurance levels in 

RTCA/DO–254 for the system or item.) 

vii. Simple and conventional systems: 

A system is considered ‘‘simple’’ or 

‘‘conventional’’ if its function, the 

technological means to implement its 

function, and its intended usage are all 

the same as, or closely similar to, that 

of previously approved systems 

commonly used. The systems that have 

established an adequate service history 

and the means of compliance for 

approval are generally accepted as 

‘‘simple’’ or ‘‘conventional.’’ Simple 

systems do not contain software or 

complex hardware requiring compliance 

by documents. These documents are the 

developmental assurance levels 

assigned in RTCA/DO–178A/B, 

Software Considerations in Airborne 

Systems and Equipment Certification, or 

RTCA/DO–254, Design Assurance 

Guidance for Airborne Electronic 

Hardware documents or later versions. 

For simple and conventional 

installations, it may be possible to 

assess a hazardous or catastrophic 

failure condition(s) as being extremely 

remote or extremely improbable, 

respectively, based on an FAA approved 

qualitative analysis. The basis for the 

assessment would be the degree of 

redundancy, the established 

independence and isolation of the 

channels, and the reliability record of 

the technology involved. Satisfactory 

service experience on similar systems 

commonly used in many airplanes may 

be sufficient when a close similarity is 

established regarding both the system 

design and operating conditions. 

viii. Installation appraisal: A 

qualitative appraisal of the integrity and 

safety of the installation. Any deviations 

from normal industry-accepted 

installation practices should be 

evaluated. 

8. Placards, Speeds, Operating 

Limitations, and Information 

Currently, § 23.853(d)(2) requires 

placards for commuter category 

airplanes to have red letters at least 1⁄2

inch high on a white background at least 

1 inch high. The letter size is not a 

requirement for the part 23 normal 

category or for the part 25 transport 

category airplanes. We propose 

removing the letter size requirement 

from this section. We also propose 

removing the ashtray requirement from 

this section since smoking is no longer 

allowed in parts 121 and 135 

operations. We propose to amend 

paragraph (d)(2) of this section to read 

‘‘Lavatories must have ‘No Smoking’ or 

‘No Smoking in Lavatory’ placards 

located conspicuously on each side of 

the entry door.’’ 

Proposed § 23.629 would allow the 

use of VDF in place of VD for flight 

testing turbojets. In addition, the 

proposed amendment for § 23.1505 

would require airspeed limits based on 

a combination of analytical (VD/MD) and 

demonstrated (VDF/MDF) dive speeds for 

turbojets. Proposed § 23.1505(c) would 

include specific turbojet speed 

designations. 

The ARC did not make a specific 

recommendation regarding § 23.1525. 

However, we propose to clarify language 

so applicants understand that additional 

equipment may be needed to operate 

their airplane. Part 23 is a minimum 

performance standard, and it may not 

include all the required equipment for 

operations under part 135. We propose 

to include parts 91 and 135 operations 

as examples of the kinds of operation 

authorized. 

Proposed § 23.1545 limits the white 

flap arc to reciprocating engine 

airplanes. This change reflects standard 

practice for turbojets and is included in 

all part 23 turbojet special conditions. 

Proposed § 23.1555(d)(3) would 

require fuel systems with a calibrated 

fuel quantity indication system to 

comply with § 23.1337(b)(1) while 

removing current placard requirements. 

Most modern turbine-powered airplanes 

have a calibrated fuel quantity 

indicating system that is density 

compensated and accurately indicates 

the actual usable fuel quantity in each 

tank. When using these types of fuel 

indicating systems, we consider the 

placards required by §§ 23.1555(d)(1) 

and (2) redundant. The placards or 

markings required by §§ 23.1555(d)(1) 

and (2) indicate the maximum capacity 

of the tank. For these reasons, we 

propose to remove the placard 

requirement for these accurate fuel 

quantity indicating systems. 

The placard requirements of 

§§ 23.1559, 23.1563 and 23.1567 have 

been a source of confusion to both FAA 

and industry personnel relative to 

placard lighting. We are proposing 

changes to these three rules to clarify 

the intent of these requirements. The 

requirements specified on the placard in 

§ 23.1559 are relative to preflight 

planning, and this placard is not 

normally referenced in flight. As long as 

the placard is ‘‘in clear view of the 

pilot’’ and the pilot can view it at night 

using a flashlight or other means, the 

intent of the rule is met. The 

requirement has been confusing for 

certification offices and this proposal 

makes the placard lighting intent clear. 

We propose to add a new paragraph 

§ 23.1559(d), which states ‘‘The placard 

required by this section need not be 

lighted.’’ 

With modern flight display 

equipment, the necessary information 

may now be available on that equipment 

and is automatically illuminated as part 

of the display. Therefore, we also 

propose to update § 23.1563 to clarify 

requirements for night lighting of the 

placard. Maneuvering speed is 

applicable to operations that may 

involve intentional large control input 

and is therefore not applicable to 

normal night operations. Most modern 

airplanes have means for the landing 

gear speed to be displayed in the 

airspeed indicator or on lighted portions 

of the landing gear control. They have 

the means for the airspeed indicator to 

display low speed awareness or other 

airspeed reference information to 

provide safety above VMC. Lighting this 

placard is unnecessary for safety and 

provides another source of unwanted 

lighting reflections in the cockpit. 

The requirements specified in 

§ 23.1567 for the limitation placard 

relate to acrobatic maneuvers and spin 

information related to preflight 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41533 

planning. Since these maneuvers are not 

normally conducted during night 

operations, the placard information is 

not required for night flight. If the 

placard is ‘‘in clear view of the pilot’’ 

and the pilot can view the placard at 

night using a flashlight or other means, 

it meets the intent of the rule. The 

proposed change to § 23.1567 clarifies 

our intent of this rule relative to 

lighting. 

We propose to incorporate the 

existing special conditions into the 

AFM requirements in §§ 23.1583, 

23.1585, and 23.1587. These are 

necessary to be consistent with the 

performance requirements proposed in 

subpart B. These requirements include 

the ARC recommended, single-engine 

climb performance increase for 

turboprops. 

III. Regulatory Notices and Analyses 

Paperwork Reduction Act 

According to the 1995 amendments to 

the Paperwork Reduction Act (5 CFR 

1320.8(b)(2)(vi)), an agency may not 

collect or sponsor the collection of 

information, nor may it impose an 

information collection requirement 

unless it displays a currently valid OMB 

control number. The OMB control 

number for this information collection 

will be published in the Federal 

Register, after the Office of Management 

and Budget approval. 

International Compatibility 

In keeping with U.S. obligations 

under the Convention on International 

Civil Aviation, it is FAA policy to 

comply with 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 proposed 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 Trade Agreements 

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

from setting standards that create 

unnecessary obstacles to the foreign 

commerce of the United States. In 

developing U.S. standards, this Trade 

Act requires agencies to consider 

international standards and, where 

appropriate, that they be the basis of 

U.S. standards. Fourth, the Unfunded 

Mandates Reform Act of 1995 (Pub. L. 

104–4) requires agencies to prepare a 

written assessment of the costs, benefits, 

and other effects of proposed or final 

rules that include a Federal mandate 

likely to result in the expenditure by 

State, local, or tribal governments, in the 

aggregate, or by the private sector, of 

$100 million or more annually (adjusted 

for inflation with base year of 1995). 

This portion of the preamble 

summarizes the FAA’s analysis of the 

economic impacts of this proposed rule. 

We suggest readers seeking greater 

detail read the full regulatory 

evaluation, a copy of which we have 

placed in the docket for this rulemaking. 

In conducting these analyses, FAA 

has determined that this proposed rule: 

(1) 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) the 

Office of Management and Budget has 

determined this proposal is 

‘‘significant’’; (4) would not have a 

significant economic impact on a 

substantial number of small entities; (5) 

would not create unnecessary obstacles 

to the foreign commerce of the United 

States; and (6) would not impose an 

unfunded mandate on state, local, or 

tribal governments, or on the private 

sector by exceeding the threshold 

identified above. These analyses are 

summarized below. 

Total Benefits and Costs of This Rule 

The estimated base case cost of this 

proposed rule is about $472,000 

($443,000 in 7 percent present value 

terms). The estimated safety benefits 

would be to avoid 14 accidents and are 

valued at about $82.7 million. The 

estimated base case efficiency benefits 

to streamline the part 23 certification 

process are valued at about $1.6 million. 

The total base case benefit is equal to 

the sum of the safety and efficiency 

benefits and is valued at about $84.2 

million. 

Who Is Potentially Affected by This 

Rule 

This proposed rulemaking will affect 

manufacturers and operators of part 23 

reciprocal engine, turboprop and 

turbojet airplanes. 

Assumptions 

The proposed rule makes the 

following assumptions: 

1. The base year is 2008. 

2. The average retirement age of a U.S. 

operated part 23 airplane is 32 years. 

3. The average part 23 airplane 

production life cycle is 24 years. 

4. The analysis period extends for 56 

(32 + 24) years. 

5. U.S companies would manufacture 

75 percent of the turbojets forecasted by 

the FAA. 

6. All business and commercial part 

23 airplanes would operate in commuter 

service. 

7. The value of a fatality avoided is 

$5.8 million. 

Benefits of This Rule 

For part 23 airplanes, we estimated 

that the proposed changes would avoid 

about 14 accidents over the 24-year 

operating lives of 37,657 newproduction airplanes. The resulting 

benefits include averted fatalities and 

injuries, loss of airplanes, investigation 

cost, and collateral damages for the 

accidents. The safety benefits for 

averting the 14 accidents are about 

$82.7 million ($17.8 million in 7 

percent present value terms). 

Other benefits of this proposal 

include FAA and industry paperwork 

and certification time saved by 

standardizing and streamlining the 

certification of part 23 airplanes. The 

base case efficiency benefits for 

standardizing and streamlining the 

certification process is valued at $1.6 

million. 

The total base case benefit is equal to 

the sum of the safety and efficiency 

benefits and is about $84.2 million 

($19.3 million in 7 percent present 

value terms). 

Costs of This Rule 

Constant-dollar (2008$) unit costs per 

aircraft by 14 CFR Part 23 could be as 

high as: $165 for turboprop airplanes 

and $6,550 for turbojet airplanes. Total 

incremental costs equal the constantdollar unit costs multiplied by the 

number of aircraft produced over 10 

years. The base case costs of this rule 

are about $472,000 ($443,000 in 7 

percent present value terms) and the 

high case costs of this rule are about 

$11.1 million ($5.0 million in 7 percent 

present value terms). 

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. 

Alternative 2—The FAA continue to 

enforce the current regulations that 

affect single engine climb performance. 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
41534 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

6 13 CFR 121.201, Size Standards Used to Define 

Small Business Concerns, Sector 48–49 

Transportation, Subsector 481 Air Transportation. 

The FAA rejected this alternative 

because the accident rate on twin piston 

engine and turboprop 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 believes that this proposed 

rule would not have a significant impact 

on a substantial number of entities. The 

purpose of this analysis is to provide the 

reasoning underlying the FAA 

determination. 

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 

proposed rule. Next we explain there 

are no relevant federal rules which may 

overlap, duplicate, or conflict with the 

proposed rule. Lastly, we will describe 

and provide an estimate of the number 

of small entities affected by the 

proposed rule and why the FAA 

believes this proposed rule would 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 proposes this action to 

amend safety and applicability 

standards of the part 23 turbojet 

industry to reflect the current needs of 

the industry, accommodate future 

trends, address emerging technologies, 

and provide for future aircraft 

operations. This proposal primarily 

standardizes and streamlines the 

certification of part 23 turbojet 

airplanes. The intent of the proposed 

changes to parts 1 and 23 are necessary 

to eliminate the current workload of 

exemptions, special conditions, and 

equivalent levels of safety 

determinations necessary to certificate 

part 23 turbojets. These proposed 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 turbojet, turboprop 

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 programs. However, in the 

past five years, the number of new 

turbojet certification programs in part 23 

has increased more than 100 percent 

over the past three decades. 

The need to incorporate these special 

conditions into part 23 stems from both 

the existing number of new jet programs 

and the expected future jet programs. 

Codifying these special conditions will 

allow manufacturers to know the 

requirements during their 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 TC an airplane and reduces 

the potential for program delays. These 

proposed changes would also clarify 

areas of frequent non-standardization 

and misinterpretation, particularly for 

electronic equipment and system 

certification. 

The revisions include general 

definitions, error correction, and 

specific requirements for performance 

and handling characteristics to ensure 

safe operation of part 23 transport 

category airplanes. The proposed 

revisions would apply to all future new 

part 23 turbojet, turboprop and 

reciprocating engine airplane 

certifications. 

We now discuss the legal basis for, 

and objective of, the proposed rule. 

Next, we discuss if there are relevant 

federal rules, which may overlap, 

duplicate, or conflict with the proposed 

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 proposed rule will 

amend Title 14 of the Code of Federal 

Regulations to address deficiencies in 

current regulations regarding the 

certification of part 23 light jets, 

turboprops and reciprocating engine 

airplanes. The proposed rule would 

clarify areas of frequent nonstandardization and misinterpretation 

and codify certification requirements 

that currently exist in special 

conditions. 

The FAA is unaware the proposed 

rule will overlap, duplicate, or conflict 

with existing Federal Rules. 

We now discuss our methodology to 

determine the number of small entities 

for which the proposed rule will apply. 

Under the RFA, the FAA must 

determine whether a proposed 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.6

There are 11 U.S. aircraft 

manufacturers currently producing part 

23 airplanes and could be affected by 

this proposal. These manufacturers are 

American Champion, Cessna, Cirrus, 

Eclipse, Hawker Beechcraft, Liberty, 

Maule, Mooney, Piper, Quest, and Sino 

Swearingen. 

Using information provided by the 

World Aviation Directory, Internet 

filings and industry contacts, 

manufacturers that are subsidiary 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41535 

7http://www.sba.gov/advo/research/us05_n6.pdf. 

businesses of larger businesses, 

manufacturers that are foreign owned, 

and businesses with more than 1,500 

employees were eliminated from the list 

of 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 proposed rule is 

2008. Although the FAA forecasts traffic 

and air carrier fleets, we can not 

determine the number of new entrants 

nor who will be in business in the 

future. Therefore we use current U.S. 

manufacturer’s revenue and 

employment in order to determine the 

number of operators this proposal 

would affect. 

The methodology discussed above 

resulted in the following six U.S. part 23 

aircraft manufacturers, with less than 

1,500 employees, shown in Table RF1. 

TABLE RF1 

Company Employees Annual revenue 

Quest ................................................................................................................................................................... 60 $4,600,000 

Maule ................................................................................................................................................................... 86 5,700,000 

Piper ..................................................................................................................................................................... 100 7,600,000 

Mooney ................................................................................................................................................................ 400 42,083,000 

Sino Swearingen .................................................................................................................................................. 400 25,300,000 

Eclipse ................................................................................................................................................................. 1,000 36,700,000 

The majority of this proposal affects 

the certification of turbojets and has a 

minor affect on the certification of 

turboprop and reciprocating engine 

airplanes by clarifying frequent nonstandardization and misinterpretations 

of the current part 23 rules. 

From the list of part 23 small entity 

U.S. airplane manufacturers above, only 

Eclipse and Sino Swearingen produce 

turbojet airplanes and Piper and Quest 

produce turboprop airplanes. The 

remaining part 23 small entity U.S. 

airplane manufacturers produce 

reciprocating engine airplanes. 

In the regulatory evaluation, we 

estimated that operators of newly 

certificated part 23 airplanes would 

incur additional fuel costs. 

Additionally, operators could incur 

costs from added weight and a reduced 

payload capacity. The U.S. Census 

Bureau data on the Small Business 

Administration’s Web site shows an 

estimate of the total number of small 

business entities who could be affected 

if they purchase newly certificated part 

23 airplanes.7 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 nonscheduled businesses are in part 25. 

Other small businesses may own aircraft 

and not be included in the U.S. Census 

Bureau Non-scheduled Air 

Transportation Industry category. The 

estimate of the affect of this proposal on 

the total number of small entities that 

operate part 23 airplanes is developed 

below. 

We now discuss our methodology to 

estimate the costs of this proposal to the 

small entities part 23 airplane 

manufacturers and operators. We will 

also discuss why the FAA believes this 

proposed rule would 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). FAA and 

the part 23 industry have worked 

together to develop common 

certification part 23 airplane 

requirements proposed in this 

rulemaking. We contacted the part 23 

aircraft manufacturers, the ARC, and 

General Aviation Manufacturers 

Association (GAMA) (an industry 

association for part 23 aircraft 

manufacturers) for specific cost 

estimates for each proposed section 

change for this 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 this 

proposed rule. We are basing our cost 

estimates for this proposed rule from 

these part 23 U.S. aircraft 

manufacturers, ARC members and 

GAMA. 

The part 23 U.S. airplane 

manufacturers, ARC members, and 

industry association informed us that 

this proposed rulemaking would add 

manufacturer certification costs for fire 

extinguishing systems, climb, and takeoff warning systems. Industry informed 

us that this proposal would save the 

manufacturers design time for the 

certification of cockpit controls. 

Industry has also informed us that every 

other proposed section of this rule is 

either clarifying, error correcting, or 

would only add minimal to no costs. 

The proposed rule adds certification 

requirements for the following part 23 

airplane categories: 

1. All turbojet airplanes, 

2. All turbojet airplanes with a 

MTOW less than 6,000 pounds, 

3. All turboprop airplanes, 

4. All reciprocal engine airplanes, and 

5. All reciprocal twin engine airplanes 

with a MTOW greater than 6,000 

pounds. 

In some cases the proposed 

regulations 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 personal use of a part 23 

airplane by analyzing the number of all 

US-operated airplanes from Table 3.1 of 

the 2006 General Aviation and Part 135 

Activity Survey. Table 3.1 shows the 

breakout of the 2006 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 2006 

General Aviation and Part 135 Activity 

Survey would operate in Commuter 

service. Table RF2 shows these results. 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
41536 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

8http://www.faa.gov/regulations_policies/policy

_guidance/benefit_cost/media/050404%20Critical

%20Values%20Dec%2031%20Report%2007

Jan05.pdf. 

TABLE RF2—2006 GENERAL AVIATION AND PART 135 ACTIVITY SURVEY—TABLE 3.1 

Aircraft type Total active Personal % Personal % Business 

Piston ............................................................................................................... 163,743 118,618 72.44 27.56 

Turboprop ........................................................................................................ 8,063 1,177 14.60 85.40 

Turbojet ............................................................................................................ 10,379 750 7.23 92.77 

Table RF3 shows the results of the 

proposed sections that add (or subtract) 

incremental costs by increasing design 

or flight testing times, adds weight, or 

reducing payload. 

TABLE RF3 

Certification Flight Operation Part 23 Airplane Categories Affected 

Part 23 Section Section title Design 

hours 

Flight test 

hours 

Additional 

weight 

Payload 

reduction Turbojet 

Turbojet 

<6,000 # 

MTOW 

Turboprop 

Reciprocal engine 

Twin reciprocal 

engine 

>6,000 # 

MTOW 

Category 

23.1193(g), 

23.1195(a), 

23.1197, 

23.1199, 

23.1201.

Cowling and Nacelle, Fire Extinguisher Systems, Fire Extinguishing 

Agents, Extinguishing Agent 

Containers, Fire 

Extinguishing 

System Materials.

................ 50 25 ................ ................ ................ X ................ ................ Commuter. 

23.63, 23.67, 

23.77.

Climb: General, 

Climb—One Engine, Balked 

Landing.

................ ................ ................ 10% ................ X X ................ X All. 

23.703 .................. Take-Off Warning 

System.

1,000 25 ................ ................ ................ X X ................ X All. 

23.777 .................. Cockpit Controls .. ¥25 ................ ................ ................ X ................ X X ................ All. 

We estimated part 23 airplane 

manufacturer fixed (added certification 

plus flight test hours) and operator 

variable (added fuel burn plus 10 

percent reduction in payload) costs and 

applied our estimated costs to expected 

fleet delivered in compliance with this 

proposal. The total cost of this rule is 

the sum of the fixed certification cost 

plus the airplane fuel-burn variable cost 

multiplied by the expected fleet 

delivered over the analysis period. 

The total fixed certification 

compliance cost equals the average 

compliance cost multiplied by the 

expected number of certifications of 

newly delivered part 23 turbojet, 

turboprop and reciprocating engine 

airplane. In the regulatory evaluation we 

estimated a base case and high case 

range for the certification costs. This 

range was based on the estimated 

number of new turbojet certifications. In 

the base case, we estimated five new 

turbojet certifications in the analysis 

interval. In the high case, we estimated 

eight new turbojet certifications. We 

will use the high cost case scenario for 

this analysis. 

We estimated the certification costs 

for fire extinguishing systems, climb, 

and take-off warning systems. Based on 

the hours provided by the part 23 U.S. 

airplane manufacturers, ARC members 

and industry association and the 

Economic Values For FAA Investment 

and Regulatory Decisions, A Guide for 

the hourly rates.8 Table RF4 shows the 

incremental certification costs estimate 

we calculated. 

TABLE RF4—HIGH COST SCENARIO FOR PART 23 MANUFACTURERS

Costs Recip Commuter TP TJ < 6,000 

Design .......................................................................................................................................... $0 $152,020 $94,496 

Design .......................................................................................................................................... (9,501) (3,801) (22,803) 

Flight Test .................................................................................................................................... 0 114,400 93,489 

Total High Cost ............................................................................................................................ (9,501) 262,620 165,181 

# Certifications ............................................................................................................................. 5 4 12 

Cost per Cert ............................................................................................................................... (1,900) 65,655 13,765 

We applied the estimated incremental 

certification costs to the each of the 

small part 23 airplane manufacturing 

average number of historical 

certifications over a ten-year period. We 

then divided the small part 23 airplane 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41537 

9Table 3.15 of the Economic Values For FAA 

Investment and Regulatory Decisions, A Guide 

10 Ibid. 

manufacturer’s annual revenue by the incremental costs. Table RF5 shows 

these results. 

TABLE RF5 

Company Employees Annual 

revenue 

Average # certs 10 

years Airplane certificated Estimated cert cost Percent 

Quest ................................ 60 $4,600,000 1.00 ........................... Turboprop .................. $65,655 1.43 

Maule ............................... 86 5,700,000 0.20 ........................... Recip ......................... ¥380 ¥0.01 

Piper ................................. 100 7,600,000 1.00 (Recip) + 33 

(TP).

Recip + Turboprop .... 65,022 0.86 

Mooney ............................ 400 42,083,000 0.17 ........................... Recip ......................... ¥317 0.00 

Sino Swearingen .............. 400 25,300,000 1.00 ........................... Turbojet ..................... 13,765 0.05 

Eclipse .............................. 1,000 36,700,00 1.00 ........................... Turbojet ..................... 13,765 0.04 

We estimated that the incremental 

fixed certification cost this proposed 

rule would be less than one percent in 

five of the six small entity part 23 

airplane manufacturers, and less than 

1.5 percent in the remaining one. We do 

not believe these are significant 

economic costs. Further, we believe that 

the manufacturers of the part 23 

airplanes would have additional costs 

savings associated with the proposal 

standardizes and streamlining the 

certification process. Additional costs 

savings of the proposed changes to parts 

1 and 23 would be to eliminate the 

current workload of exemptions, special 

conditions, and equivalent levels of 

safety necessary to certificate part 23 

turbojets and by clarifying frequent nonstandardization and misinterpretations 

of current part 23 rules. 

To estimate the incremental variable 

costs to a part 23 operator, we 

multiplied the annual per-unit fuel burn 

cost by the expected fleet delivered over 

the analysis interval. 

In the regulatory evaluation, we 

estimated a minimal base and high case 

cost for the 10 percent loss in capacity 

occurs the operators may incur. The 

base case was a no cost scenario because 

the average GA airplane has about 3.7 

seats and flies about half full.9 The 

cargo load factor for all cargo carriers is 

60 percent.10 Therefore, we conclude 

that the 10 percent reduction in payload 

caused by the proposed sections on 

climb and balked landings could have a 

minimum cost impact on part 23 

airplanes for the base case. For the high 

case we realize that a percentage of the 

part 23 airplanes, in commuter service, 

could have a load factor over 90 percent 

on some of their flights. Although we 

believe any capacity affected would be 

distributed over other flights in the 

operator’s network, we estimate the cost 

of a 10 percent payload capacity 

reduction. Table RF6 shows the results 

of our calculations. 

TABLE RF6 

Recip TurboProp Commuter TP Total TJ TJ<6,000 

Base Case Cost ................................................................... $0 $0 $8,430 $0 $0 

High Case Cost .................................................................... $0 $0 $1,413,692 $0 $3,086,919 

Number of A/P ..................................................................... 23,160 1,248 1,066 11,040 1,143 

Base Case Cost / A/P .......................................................... $0 $0 $8 $0 $0 

High Case Cost / A/P .......................................................... $0 $0 $1,326 $0 $2,700 

A/P Value ............................................................................. $431,681 $3,389,054 $3,389,054 $6,300,000 $6,300,000 

% Base of Value .................................................................. 0.00% 0.00% 0.00% 0.00% 0.00% 

% High of Value ................................................................... 0.00% 0.00% 0.04% 0.00% 0.04% 

For this proposal, our high case 

estimate for small business part 23 

operators of turboprop airplanes would 

pay an additional $1,326 to operate a 

newly certificated airplane. Operators of 

newly certificated and delivered part 23 

turbojet airplanes with a maximum take 

off weight less than 6,000 pounds would 

pay an additional $2,700 to operate a 

newly certificated airplane. Operators 

would not incur these costs unless they 

purchase a newly certificated part 23 

airplane. 

We do not believe that these 

proposals costs would 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 0.04 percent for 

a turboprop and 0.04 percent for a 

turbojet with a maximum take-off 

weight less than 6,000 pounds, of the 

price of a newly certificated airplane. 

Therefore the FAA certifies that this 

proposed rule would not have a 

significant economic impact on a 

substantial number of small entities. 

The FAA solicits comments regarding 

this determination. 

International Trade Impact Assessment 

The Trade Agreements Act of 1979 

(Pub. L. 96–39) prohibits Federal 

agencies from establishing any 

standards or engaging in related 

activities that create unnecessary 

obstacles to the foreign commerce of the 

United States. Legitimate domestic 

objectives, such as safety, are not 

considered unnecessary obstacles. 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 

has no basis for believing the rule will 

impose substantially different costs on 

domestic and international entities. 

Thus the FAA believes the rule has a 

neutral trade impact. 

Unfunded Mandates Assessment 

Title II of the Unfunded Mandates 

Reform Act of 1995 (Pub. L. 104–4) 

requires each Federal agency to prepare 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
41538 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

a written statement assessing the effects 

of any Federal mandate in a proposed or 

final agency rule that may result in an 

expenditure of $100 million or more (in 

1995 dollars) in any one year by State, 

local, and tribal governments, in the 

aggregate, or by the private sector; such 

a mandate is deemed to be a ‘‘significant 

regulatory action.’’ The FAA currently 

uses an inflation-adjusted value of 

$136.1 million in lieu of $100 million. 

This proposed rule does not contain 

such a mandate; therefore, the 

requirements of Title II of the Act do not 

apply. 

Executive Order 13132, Federalism 

The FAA has analyzed this proposed 

rule under the principles and criteria of 

Executive Order 13132, Federalism. We 

determined that this action would not 

have a substantial direct effect on the 

States, on the relationship between the 

national Government and the States, or 

on the distribution of power and 

responsibilities among the various 

levels of government, and, therefore, 

would not have federalism implications. 

Regulations Affecting Intrastate 

Aviation in Alaska 

Section 1205 of the FAA 

Reauthorization Act of 1996 (110 Stat. 

3213) requires the Administrator, when 

modifying regulations in Title 14, Code 

of Federal Regulations in a manner 

affecting intrastate aviation in Alaska, to 

consider the extent to which Alaska is 

not served by transportation modes 

other than aviation and to establish 

appropriate regulatory distinctions. 

Because this proposed rule would apply 

to the certification of future designs of 

transport category airplanes and their 

subsequent operation, it could, if 

adopted, affect intrastate aviation in 

Alaska. The FAA, therefore, specifically 

requests comments on whether there is 

justification for applying the proposed 

rule differently in intrastate operations 

in Alaska. 

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 proposed 

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 has analyzed this NPRM 

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 while it is a 

‘‘significant regulatory action,’’ it is not 

likely to have a significant adverse effect 

on the supply, distribution, or use of 

energy. 

Additional Information 

Comments Invited 

The FAA invites interested persons to 

participate in this rulemaking by 

submitting written comments, data, or 

views. We also invite comments relating 

to the economic, environmental, energy, 

or federalism impacts that might result 

from adopting the proposals in this 

document. The most helpful comments 

reference a specific portion of the 

proposal, explain the reason for any 

recommended change, and include 

supporting data. To ensure the docket 

does not contain duplicate comments, 

please send only one copy of written 

comments, or if you are filing comments 

electronically, please submit your 

comments only one time. 

We will file in the docket all 

comments we receive, as well as a 

report summarizing each substantive 

public contact with FAA personnel 

concerning this proposed rulemaking. 

Before acting on this proposal, we will 

consider all comments we receive on or 

before the closing date for comments. 

We will consider comments filed after 

the comment period has closed if it is 

possible to do so without incurring 

expense or delay. We may change this 

proposal in light of the comments we 

receive. 

Proprietary or Confidential Business 

Information 

Do not file in the docket information 

that you consider to be proprietary or 

confidential business information. Send 

or deliver this information directly to 

the person identified in the FOR FURTHER

INFORMATION CONTACT section of this 

document. You must mark the 

information that you consider 

proprietary or confidential. If you send 

the information on a disk or CD ROM, 

mark the outside of the disk or CD ROM, 

and also identify electronically within 

the disk or CD ROM the specific 

information that is proprietary or 

confidential. 

Under 14 CFR 11.35(b), when we are 

aware of proprietary information filed 

with a comment, we do not place it in 

the docket. We hold it in a separate file 

to which the public does not have 

access, and we place a note in the 

docket that we have received it. If we 

receive a request to examine or copy 

this information, we treat it as any other 

request under the Freedom of 

Information Act (5 U.S.C. 552). We 

process such a request under the DOT 

procedures found in 49 CFR part 7. 

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, 

ARM–1, 800 Independence Avenue 

SW., Washington, DC 20591, or by 

calling 202–267–9680. Make sure to 

identify the docket number or notice 

number of this rulemaking. 

You may access all documents the 

FAA considered in developing this 

proposed rule, including economic 

analyses and technical reports, from the 

Internet through the Federal 

eRulemaking Portal referenced in 

paragraph (1). 

List of Subjects 

14 CFR Part 1 

Air transportation. 

14 CFR Part 23 

Aviation Safety, Signs, Symbols, 

Aircraft. 

The Proposed Amendments 

In consideration of the foregoing, the 

Federal Aviation Administration 

proposes to amend Chapter I of Title 14, 

Code of Federal Regulations, as follows: 

PART 1—DEFINITIONS AND 

ABBREVIATIONS 

1. The authority citation for part 1 

continues to read as follows: 

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

2. Revise the definitions of ‘‘Rated 

takeoff power’’ and ‘‘Rated takeoff 

thrust’’ and add the definitions of 

‘‘Turbine engine’’, ‘‘Turbojet engine’’, 

and ‘‘Turboprop engine’’ in alphabetical 

order in § 1.1 to read as follows: 

§ 1.1 General definitions. 

* * * * * 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41539 

Rated takeoff power, with respect to 

reciprocating, turbopropeller, and 

turboshaft engine type certification, 

means the approved brake horsepower 

that is developed statically under 

standard sea level conditions, within 

the engine operating limitations 

established under part 33 of this 

chapter, and limited in use— 

(1) To periods of not more than 5 

minutes for takeoff operations with 

reciprocating, turbopropeller, and 

turboshaft engines; and 

(2) When specifically requested by the 

engine manufacturer, to periods of not 

more than 10 minutes for one-engineinoperative takeoff operations with 

turbopropeller engines. 

Rated takeoff thrust, with respect to 

turbojet engine type certification, means 

the approved turbojet thrust that is 

developed statically under standard sea 

level conditions, without fluid injection 

and without the burning of fuel in a 

separate combustion chamber, within 

the engine operating limitations 

established under part 33 of this 

chapter, and limited in use— 

(1) To periods of not more than 5 

minutes for takeoff operations; and 

(2) When specifically requested by the 

engine manufacturer, to periods of not 

more than 10 minutes for one-engineinoperative takeoff operations. 

* * * * * 

Turbine engine, with respect to part 

23 airplane type certification, consists of 

an air compressor, a combustion 

section, and a turbine. Thrust is 

produced by increasing the velocity of 

the air flowing through the engine. 

Turbojet engine, with respect to part 

23 airplane type certification, is a 

turbine engine which produces its 

thrust entirely by accelerating the air 

through the engine. 

Turboprop engine, with respect to 

part 23 airplane type certification, is a 

turbine engine which drives a propeller 

through a reduction gearing 

arrangement. Most of the energy in the 

exhaust gases is converted into torque, 

rather than using its acceleration to 

drive the airplane. 

* * * * * 

PART 23—AIRWORTHINESS 

STANDARDS: NORMAL, UTILITY, 

ACROBATIC, AND COMMUTER 

CATEGORY AIRPLANES 

3. The authority citation for part 23 

continues to read as follows: 

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

44702, 44704. 

4. 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. * * * 

* * * * * 

5. Amend § 23.45 by revising the 

introductory text of paragraph (h) to 

read as follows: 

§ 23.45 General. 

* * * * * 

(h) For multiengine turbojet powered 

airplanes over 6,000 pounds in the 

normal, utility, and acrobatic category 

and commuter category airplanes the 

following also apply: 

* * * * * 

6. 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— 

* * * * * 

7. 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 turbojet airplanes 

of more than 6,000 pounds maximum 

weight and commuter category 

airplanes, the following apply: 

* * * * * 

8. Amend § 23.53 by revising 

paragraph (c) to read as follows: 

§ 23.53 Takeoff performance. 

* * * * * 

(c) For normal, utility, and acrobatic 

category multiengine turbojet airplanes 

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. 

9. Amend § 23.55 by revising the 

introductory text to read as follows: 

§ 23.55 Accelerate-stop distance. 

For normal, utility, and acrobatic 

category multiengine turbojet airplanes 

of more than 6,000 pounds maximum 

weight and commuter category 

airplanes, the accelerate-stop distance 

must be determined as follows: 

* * * * * 

10. Amend § 23.57 by revising the 

introductory text to read as follows: 

§ 23.57 Takeoff path. 

For normal, utility, and acrobatic 

category multiengine turbojet airplanes 

of more than 6,000 pounds maximum 

weight and commuter category 

airplanes, the takeoff path is as follows: 

* * * * * 

11. 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 turbojet airplanes 

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. 

* * * * * 

12. Amend § 23.61 by revising the 

introductory text to read as follows: 

§ 23.61 Takeoff flight path. 

For normal, utility, and acrobatic 

category multiengine turbojet airplanes 

of more than 6,000 pounds maximum 

weight and commuter category 

airplanes, the takeoff flight path must be 

determined as follows: 

* * * * * 

13. 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 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
41540 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

and ambient temperature within the 

operational limits established for takeoff 

and landing, respectively, with— 

* * * * * 

14. Amend § 23.67 by: 

a. Revising paragraph (b) introductory 

text and (b)(1) introductory text; 

b. Redesignating paragraph (c) as 

paragraph (d) 

c. Revising newly redesignated 

paragraph (d) introductory text, 

paragraph (d)(2) introductory text, 

paragraph (d)(3) introductory text, and 

paragraph (d)(4) introductory text; and 

d. Adding new paragraph (c). 

The revisions and addition 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 

may be no less than 1 percent with 

the— 

* * * * * 

(c) For normal, utility, and acrobatic 

category turbojet engine-powered 

airplanes of 6,000 pounds or less 

maximum weight— 

(1) The steady gradient of climb at an 

altitude of 400 feet above the takeoff 

may 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 turbojet powered airplanes 

over 6,000 pounds maximum weight in 

the normal, utility and acrobatic 

category and commuter category 

airplanes, the following apply: 

* * * * * 

(2) Takeoff; landing gear retracted. 

The steady gradient of climb at an 

altitude of 400 feet above the takeoff 

surface must be at least 2.0 percent of 

two-engine airplanes, 2.3 percent for 

three-engine airplanes, and 2.6 percent 

for four-engine airplanes with— 

* * * * * 

(3) Enroute. The steady gradient of 

climb at an altitude of 1,500 feet above 

the takeoff or landing surface, as 

appropriate, must be at least 1.2 percent 

for two-engine airplanes, 1.5 percent for 

three-engine airplanes, and 1.7 percent 

for four-engine airplanes with— 

* * * * * 

(4) Discontinued approach. The 

steady gradient of climb at an altitude 

of 400 feet above the landing surface 

must be at least 2.1 percent for twoengine airplanes, 2.4 percent for threeengine airplanes, and 2.7 percent for 

four-engine airplanes, with— 

* * * * * 

15. 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 turbojet engine-powered 

airplanes 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. 

16. 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— 

* * * * * 

17. Amend § 23.175 by adding a new 

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

§ 23.175 Demonstration of static 

longitudinal stability. 

* * * * * 

(b) * * * 

(3) 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. 

* * * * * 

18. 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 

the landing gear or wing flap operating 

limit speeds, or VNO or 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 may 

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, 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41541 

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 angle 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 

appropriate for the airplane may not 

result in uncontrollable flight 

characteristics. 

19. 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 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. 

* * * * * 

20. Amend § 23.201 by revising 

paragraphs (d) and (e) and by adding a 

new paragraph (f) 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 above 

25,000 feet, during the entry into and 

the recovery from stalls performed 

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 little to 

no effect at low speeds. 

(5) Power: 

(i) Power/Thrust off; and 

(ii) For reciprocating engine powered 

airplanes: 75 percent 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 must 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 1.6 

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. 

21. 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 little to 

no effect at low speeds. 

(5) Power: 

(i) Power/Thrust off; and 

(ii) For reciprocating engine powered 

airplanes: 75 percent 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 1.6 

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. 

22. Revise § 23.251 to read as follows: 

§ 23.251 Vibration and buffeting. 

(a) There may 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 

may 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 may 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 and 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 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
41542 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

normal operations. Probable inadvertent 

excursions beyond the boundaries of the 

buffet onset envelopes may not result in 

unsafe conditions. 

23. Amend § 23.253 by revising 

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

adding a new paragraph (b)(3) to read as 

follows: 

§ 23.253 High speed characteristics. 

* * * * * 

(b) * * * 

(1) Exceptional piloting strength or 

skill; 

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

turbojet, 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. 

* * * * * 

24. 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 

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 mis-trim 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 +2.5g; or 

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

an acceptable method to ¥1g and +2.5g. 

(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 1g 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 1.5g 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 1.5g. 

(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. 

25. Amend § 23.561 by adding new 

paragraphs (e)(1) and (e)(2) to read as 

follows: 

§ 23.561 General. 

* * * * * 

(e) * * * 

(1) For turbojet 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 

18.0g plus the maximum takeoff engine 

thrust; or 

(ii) The airplane structure is designed 

to deflect the engine and its attached 

accessories away from the cabin should 

the engine mounts fail. 

(2) [Reserved] 

26. 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 turbojet powered 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 turbojet powered 

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— 

HIC = t t

t t

a t dt

t

t

Max

( ) 2 − ( ) − ( ) ⎡

⎣

⎢

⎢

⎤

⎦

⎥

⎥

⎧

⎨

⎪

⎩

⎪

⎫

⎬

⎪

⎭

⎪ 1 ∫ 2 1 1

2 2 5

1 .


srobinson on DSKHWCL6B1PROD with PROPOSALS2EP17AU09.000</GPH>
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41543 

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 

expressed as a multiple of g (units of 

gravity). 

* * * * * 

27. 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 and the evaluation must 

factor in the environmental 

requirements of § 23.841. 

28. Amend § 23.573 by adding a new 

paragraph (c) to read as follows: 

§ 23.573 Damage tolerance and fatigue 

evaluation of structure. 

* * * * * 

(c) If certification for operation above 

41,000 feet is requested, the damage 

tolerance evaluation of this paragraph 

for the fuselage pressure boundary must 

factor in the requirements of § 23.841. 

29. Amend § 23.574 by adding a new 

paragraph (c) to read as follows: 

§ 23.574 Metallic damage tolerance and 

fatigue evaluation of commuter category 

airplanes. 

* * * * * 

(c) If certification for operation above 

41,000 feet is requested, the damage 

tolerance evaluation of this paragraph 

for the fuselage pressure boundary must 

factor in the requirements of § 23.841. 

30. Amend § 23.629 by revising 

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

read as follows: 

§ 23.629 Flutter. 

* * * * * 

(b) * * * 

(1) Proper and adequate attempts to 

induce flutter have been made within 

the speed range up to VD/MD; 

* * * * * 

(3) A proper margin of damping exists 

at VD/MD, or VDF/MDF for turbojet 

airplanes; and 

(4) As VD/MD (or VDF/MDF for turbojet 

airplanes) is approached, there may not 

be a 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/MD, or 1.2 VDF/MDF

for turbojet airplanes. 

* * * * * 

31. Amend § 23.703 by revising the 

introductory text and paragraph (b) to 

read as follows: 

§ 23.703 Takeoff warning system. 

For all airplanes with a maximum 

weight more than 6,000 pounds and all 

turbojet airplanes, 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: 

* * * * * 

(b) 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. 

32. 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. 

33. 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 at least one inch higher 

or longer than propeller (rpm control) or 

mixture controls to make them more 

prominent. 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. 

* * * * * 

34. 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 or exits 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 in a ditching 

emergency. For commuter category 

airplanes, the clear opening of such exit 

or exits must meet the requirements 

defined in paragraph (d) of this section. 

35. Amend § 23.831 by adding 

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

§ 23.831 Ventilation. 

* * * * * 

(c) For turbojet powered pressurized 

airplanes, 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 crew members to perform their 

duties without undue discomfort or 

fatigue and to provide reasonable 

passenger comfort. 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 must not be less than 0.4 pounds 

per minute for any period exceeding 

five minutes. 

(d) Other probable and improbable 

Environmental Control System failure 

conditions that adversely affect the 

passenger and crew compartment 

environmental conditions may not affect 

crew performance so as to result in a 

hazardous condition, and no occupant 

shall sustain permanent physiological 

harm. 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
41544 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

36. Amend § 23.841 by revising 

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

paragraphs (c), (d), and (e) 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 the decompression, the 

cabin altitude shall 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 crew 

action beyond normal pressurization 

system operation. 

(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, 

(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 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. 

Note: For Figure 1, time starts at the 

moment cabin altitude exceeds 10,000 feet 

during decompression. 


srobinson on DSKHWCL6B1PROD with PROPOSALS2EP17AU09.001</GPH>
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41545 

Note: For Figure 2, time starts at the 

moment cabin altitude exceeds 10,000 feet 

during decompression. 

(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. 

(e) If certification for operation above 

41,000 feet is requested, additional 

damage-tolerance requirements are 

necessary to prevent fatigue damage that 

could result in a loss of pressure that 

exceeds the requirements of paragraphs 

(c) and (d) of this section. Sufficient full 

scale fatigue test evidence must be 

provided to demonstrate that this type 

of pressure loss due to fatigue cracking 

will not occur within the Limit of 

Validity of the Maintenance program for 

the airplane. In addition, a damage 

tolerance evaluation of the fuselage 

pressure boundary must be performed 

assuming visually detectable cracks and 

the maximum damage size for which the 

requirements of paragraphs (c) and (d) 

of this section can be met. Based on this 

evaluation, inspections or other 

procedures must be established and 

included in the Limitations Section of 

the Instructions for Continued 

Airworthiness required by § 23.1529. 

37. 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. 

* * * * * 

38. 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 

part I of Appendix F of this part. 

39. Amend § 23.903 by revising 

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

§ 23.903 Engines. 

* * * * * 

(b) * * * 

(2) 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 have the ability to 

maintain controlled flight and landing. 

* * * * * 

40. Amend § 23.1141 by adding a new 

paragraph (h) to read as follows: 

§ 23.1141 Powerplant controls: General. 

* * * * * 

(h) Electronic engine control system 

installations must meet the 

requirements of § 23.1309. 

41. 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. 

42. Amend § 23.1193 by revising 

paragraph (g) to read as follows: 

§ 23.1193 Cowling and nacelle. 

* * * * * 

(g) In addition, for all turbojet 

airplanes and commuter category 

airplanes, 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. 

43. Amend § 23.1195 by revising the 

introductory text of paragraph (a) and by 

revising paragraph (a)(2) to read as 

follows: 


srobinson on DSKHWCL6B1PROD with PROPOSALS2EP17AU09.002</GPH>
41546 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

§ 23.1195 Fire extinguishing systems. 

(a) For all turbojet airplanes and 

commuter category airplanes, fire 

extinguishing 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. 

* * * * * 

44. Amend § 23.1197 by revising the 

introductory text to read as follows: 

§ 23.1197 Fire extinguishing agents. 

For all turbojet airplanes and 

commuter category airplanes, the 

following applies: 

* * * * * 

45. Amend § 23.1199 by revising the 

introductory text to read as follows: 

§ 23.1199 Extinguishing agent containers. 

For all turbojet airplanes and 

commuter category airplanes, the 

following applies: 

* * * * * 

46. Amend § 23.1201 by revising the 

introductory text to read as follows: 

§ 23.1201 Fire extinguishing systems 

materials. 

For all turbojet airplanes and 

commuter category airplanes, the 

following apply: 

* * * * * 

47. 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. 

48. Amend § 23.1303 by revising 

paragraph (c) to read as follows: 

§ 23.1303 Flight and navigation 

instruments. 

* * * * * 

(c) A magnetic direction indicator. 

* * * * * 

49. Amend § 23.1305 by adding a new 

paragraph (f) to read as follows: 

§ 23.1305 Powerplant instruments. 

* * * * * 

(f) Powerplant indicators must either 

provide trend or rate-of-change 

information, or have the ability to: 

(1) Allow the pilot to assess necessary 

trend information quickly, including if 

and when this information is needed 

during engine restart; 

(2) Allow the pilot to assess how close 

the indicated parameter is relative to a 

limit; 

(3) Forewarn the pilot before the 

parameter reaches an operating limit; 

and 

(4) For multiengine airplanes, allow 

the pilot to quickly and accurately 

compare engine-to-engine data. 

50. Revise § 23.1307 to read as 

follows: 

§ 23.1307 Miscellaneous equipment. 

The equipment necessary for an 

airplane to operate at the maximum 

operating altitude and in the kinds of 

operations (e.g., part 91, part 135) and 

meteorological conditions for which 

certification is requested and is 

approved in accordance with § 23.1559 

must be included in the type design. 

51. Revise § 23.1309 to read as 

follows: 

§ 23.1309 Equipment, systems, and 

installations. 

The requirements of this section, 

except as identified below, 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. It does not 

supersede any specific requirements 

contained in another section of part 23. 

This section should be used to 

determine software and hardware 

development assurance levels. This 

section does not apply to the 

performance, flight characteristics 

requirements of subpart B of this part, 

and structural loads and strength 

requirements of subparts C and D of this 

part, but it does apply to any system on 

which compliance with the 

requirements of subparts B, C, D, and E 

of this part are based. The flight 

structure such as wing, empennage, 

control surfaces and their simple, or 

simple and conventional systems, the 

fuselage, engine mounting, and landing 

gear and their related primary 

attachments are excluded. For example, 

it does not apply to an airplane’s 

inherent stall characteristics or their 

evaluation of § 23.201, but it does apply 

to a stick pusher (stall barrier) system 

installed to attain compliance with 

§ 23.201. 

(a) The airplane equipment and 

systems must be designed and installed 

so that: 

(1) Those required for type 

certification or by operating rules, or 

whose improper functioning would 

reduce safety, perform as intended 

under the airplane operating and 

environmental conditions, including 

radio frequency energy and the effects 

(both direct and indirect) of lightning 

strikes. 

(2) Those required for type 

certification or by operating rules and 

other equipment and systems do 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. 

(3) For minor, major, hazardous, or 

catastrophic failure condition(s), the 

results of certification testing must not 

be inconsistent with the results of the 

safety analysis process. 

(b) The airplane systems and 

associated components for the 

appropriate classes of airplane, 

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; 

(3) Each major failure condition is 

remote; and 

(4) Each failure condition meets the 

relationship among airplane classes, 

probabilities, severity of failure 

condition(s), and software and complex 

hardware development assurance levels 

shown in Appendix K of this part. 

(5) Compliance with the requirements 

of paragraph (b)(2) of this section may 

be shown by analysis and, where 

necessary, by appropriate ground, flight, 

or simulator tests. The analysis must 

consider— 

(i) Possible modes of failure, 

including malfunctions and damage 

from external sources; 

(ii) The probability of multiple 

failures and the probability of 

undetected faults; 

(iii) The resulting effects of the 

airplane and occupants, considering the 

stage of flight and operating conditions; 

and 

(iv) The crew warning cues, corrective 

action required, and the crew’s 

capability of determining faults. 

(c) Functional failure condition(s) that 

are classified as minor do not require a 

quantitative analysis, but verification by 

a design and installation appraisal is 

required. 

(d) Systems with major failure 

condition(s)— 

(1) May be verified by a qualitative 

analysis, if the systems are simple, 

simple and conventional, or 

conventional and redundant. 

(2) Must be verified by a qualitative 

and quantitative analysis, if the systems 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41547 

do not meet the condition(s) prescribed 

in paragraph (d)(1) of this section. 

(e) Systems with hazardous or 

catastrophic failure condition(s)— 

(1) May be verified by a qualitative 

and quantitative analysis, if the systems 

are simple and conventional. 

(2) Must be verified by a qualitative 

and quantitative analysis if the systems 

are not simple and conventional. 

(f) Information concerning an unsafe 

system operating condition(s) must be 

provided to the crew to enable them to 

take appropriate corrective action. A 

warning indication must be provided if 

immediate corrective action is required. 

Systems and controls, including 

indications and annunciations must be 

designed to minimize crew errors, 

which could create additional hazards. 

52. Add a new § 23.1310 to read as 

follows: 

§ 23.1310 Power source capacity and 

distribution. 

(a) Each item of equipment, each 

system, and each installation whose 

functioning is required by this chapter 

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 power 

distribution system with the system 

functioning normally. 

(2) Essential loads after failure of— 

(i) Any one engine on two-engine 

airplanes, or 

(ii) Any two engines on an airplane 

with three or more engines, or 

(iii) Any power converter or energy 

storage device. 

(3) Essential loads for which an 

alternate source of power is required, as 

applicable, by the operating rules of this 

chapter, after any failure or malfunction 

in any one power supply system, 

distribution system, or other utilization 

system. 

(b) In determining compliance with 

paragraph (a)(2) of this section, the 

power loads may be assumed to be 

reduced under a monitoring procedure 

consistent with safety in the kinds of 

operations authorized. Loads not 

required in controlled flight need not be 

considered for the two-engineinoperative condition on airplanes with 

three or more engines. 

53. 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) Have an independent magnetic 

direction indicator and an independent 

secondary mechanical altimeter, 

airspeed indicator, and attitude 

instrument or 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, 

when appropriate, trend information 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 with a single pilot action or by 

automatic means for continued safe 

operation, after any single failure or 

probable combination of failures. 

* * * * * 

54. 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 turbojet 

airplanes 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. 

* * * * * 

55. 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) An additional display of 

parameters for heading, altitude, 

airspeed, and attitude that is 

independent from the airplane’s 

primary electrical power system. 

56. Amend § 23.1353 by revising 

paragraph (h) to read as follows: 

§ 23.1353 Storage battery design and 

installation. 

* * * * * 

(h) 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: 

(1) At least 30 minutes for airplanes 

that are certificated with a maximum 

altitude of 25,000 feet or less, and 

(2) At least 60 minutes for airplanes 

that are certificated with a maximum 

altitude over 25,000 feet. 

57. Revise § 23.1443 to read as 

follows: 

§ 23.1443 Minimum mass flow of 

supplemental oxygen. 

(a) If the airplane is to be certified 

above 40,000 feet, a continuous flow 

oxygen system must be provided for 

each passenger and crewmember. 

(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. 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
41548 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

(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. 

(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 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). 

58. 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. 

59. 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 40,000 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. 

60. Amend § 23.1505 by revising 

paragraph (c) to read as follows: 

§ 23.1505 Airspeed limitations. 

* * * * * 

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

section do not apply to turbine airplanes 

or the 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. 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 turbojets, and the 

maximum speed shown under § 23.251 

to make it highly improbable that the 

latter speeds will be inadvertently 

exceeded in operations. The speed 

margin between VMO/MMO and VD/MD, 


srobinson on DSKHWCL6B1PROD with PROPOSALS2EP17AU09.003</GPH>
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41549 

or VDF/MDF for turbojets, 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. 

61. Revise § 23.1525 to read as 

follows: 

§ 23.1525 Kinds of operation. 

The kinds of operation authorized 

(e.g., VFR, IFR, day, night, part 91, part 

135) and the meteorological conditions 

(e.g., icing) to which the operation of the 

airplane is limited or from which it is 

prohibited, must be established 

appropriate to the installed equipment. 

62. 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 

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 

the lowest value of VMO/MMO

established for any altitude up to the 

maximum operating altitude for the 

airplane. 

63. 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. 

* * * * * 

64. 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. 

65. Amend § 23.1563 by adding a new 

paragraph (d) to read as follows: 

§ 23.1563 Airspeed placards. 

* * * * * 

(d) The airspeed placard 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. 

66. Amend § 23.1567 by adding a new 

paragraph (e) to read as follows: 

§ 23.1567 Flight maneuver placard. 

* * * * * 

(e) The placards required by this 

section need not be lighted. 

67. 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 to read as follows: 

§ 23.1583 Operating limitations. 

* * * * * 

(c) * * * 

(3) For reciprocating engine-powered 

airplanes of more than 6,000 pounds 

maximum weight, single-engine 

turbines, and multiengine turbine 

airplanes 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 turbojet powered 

airplanes 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 turbojet powered 

airplanes 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— 

* * * * * 

68. 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 

turbojet powered airplanes over 6,000 

pounds, and commuter category 

airplanes, the information must include 

the following: 

* * * * * 

69. 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 turbojet 

powered airplanes over 6,000 pounds, 

and commuter category airplanes, the 

following information must be 

furnished— 

* * * * * 

70. Amend Appendix F to Part 23 by: 

a. Redesignating the existing text as 

Part I and adding a new Part I heading; 

b. Removing the introductory 

paragraph; and 

c. Adding a new Part II. 

The additions read as follows: 

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. 


srobinson on DSKHWCL6B1PROD with PROPOSALS2
41550 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

(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 

(495 mm) deep by 28 (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 12 7⁄8 by 18 1⁄2 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 3a and 3b. 


srobinson on DSKHWCL6B1PROD with PROPOSALS2EP17AU09.004</GPH> EP17AU09.005</GPH>
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41551 

(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 noncombustible sheets of material are available 

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

A sliding platform that is deeper than the 2- 


srobinson on DSKHWCL6B1PROD with PROPOSALS2EP17AU09.006</GPH>
41552 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

inch (50.8 mm) 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 must 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. 


srobinson on DSKHWCL6B1PROD with PROPOSALS2EP17AU09.007</GPH> EP17AU09.008</GPH>
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41553 

(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/ft2 -second (0 to 5.7 

Watts/cm2). 

(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. 

(B) The standardized transducer must meet 

the specifications given in paragraph VI(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), nor greater than 0.375 inches (9.5 mm). 

(H) The range used in calibration must be 

at least 0–3.5 BTUs/ft2 second (0–3.9 Watts/ 

cm2) and no greater than 0–5.7 BTUs/ft2

second (0–6.4 Watts/cm2). 

(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. 


srobinson on DSKHWCL6B1PROD with PROPOSALS2EP17AU09.009</GPH>
41554 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

(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 over-cut enough 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 

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

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

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

(584 mm) 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. 

TABLE 1—CALIBRATION TABLE

Position BTU’s/feet2 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 must 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 (51 

mm) in length, must be centered 3 inches 

± 1⁄2 inch (76 mm ± 13 mm) 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. 


srobinson on DSKHWCL6B1PROD with PROPOSALS2EP17AU09.010</GPH>
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 41555 

(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. 

71. Add a new Appendix K to part 23 

to read as follows: 

Appendix K to Part 23—Relationship 

Among Airplane Classes, Probabilities, 

Severity of Failure Conditions, and 

Software and Complex Hardware 

Development Assurance Levels 

Classification of failure 

conditions 

No safety effect Minor Major Hazardous Catastrophic 

Allowable qualitative 

probability 

No probability 

requirement 

Probable Remote Extremely remote Extremely improbable 

Effect on Airplane ....... No effect on operational capabilities 

or safety.

Slight reduction in 

functional capabilities or safety margins.

Significant reduction 

in functional capabilities or safety 

margins.

Large reduction in 

functional capabilities or safety margins.

Normally with hull 

loss. 

Effect on Occupants ... Inconvenience for 

passengers.

Physical discomfort 

for passengers.

Physical distress to 

passengers, possibly including injuries.

Serious or fatal injury 

to an occupant.

Multiple fatalities 

Effect on Flight Crew .. No effect on flight 

crew.

Slight increase in 

workload or use of 

emergency procedures.

Physical discomfort or 

a significant increase in workload.

Physical distress or 

excessive workload 

impairs ability to 

perform tasks.

Fatal Injury or incapacitation. 

Classes of Airplanes Allowable Quantitative Probabilities and Software (SW) and Complex Hardware (HW) Development Assurance Levels 

(Note 2) 

Class I 

(Typically SRE under 

6,000#).

No Probability or SW 

& HW Development 

Assurance Levels 

Requirement.

<10¥3, Note 1, P=D <10¥4, Notes 1 & 4, 

P=C, S=D.

<10¥5, Notes 4, P=C, 

S=D.

<10¥6, Note 3, P=C, 

S=C. 

Class II 

(Typically MRE, STE, 

or MTE under 

6,000#).

No Probability or SW 

& HW Development 

Assurance Levels 

Requirement.

<10¥3, Note 1, P=D <10¥5, Notes 1 & 4, 

P=C, S=D.

<10¥6, Notes 4, P=C, 

S=C.

<10¥7, Note 3, P=C, 

S=C. 


srobinson on DSKHWCL6B1PROD with PROPOSALS2EP17AU09.011</GPH>
41556 Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 / Proposed Rules 

Class III 

(Typically SRE, STE, 

MRE, & MTE equal 

or over 6,000#).

No Probability or SW 

& HW Development 

Assurance Levels 

Requirement.

<10¥3, Note 1, P=D <10¥5, Notes 1 & 4, 

P=C, S=D.

<10¥7, Notes 4, P=C, 

S=C.

<10¥8, Note 3, P=B, 

S=C. 

Class IV 

(Typically Commuter 

Category).

No Probability or SW 

& HW Development 

Assurance Levels 

Requirement.

<10¥3, Note 1, P=D <10¥5, Notes 1 & 4, 

P=C, S=D.

<10¥7, Notes 4, P=B, 

S=C.

<10¥9, Note 3, P=A, 

S=B. 

Note 1: Numerical values indicate an order of probability range and are provided here as a reference. 

Note 2: The alphabets denote the typical SW and HW Development Assurance Levels for Primary System (P) and Secondary System (S). For 

example, HW or SW Development Assurance Level A on Primary System is noted by P=A. 

Note 3: At airplane function level, no single failure will result in a Catastrophic Failure Condition. 

Note 4: Secondary System (S) may not be required to meet probability goals. If installed, S must meet stated criteria. 

Acronyms: SRE—single, reciprocating engine, MRE—multiple, reciprocating engines, STE—single, turbine engine, MTE—multiple, turbine engines, SW—software, HW—hardware. 

Issued in Washington, DC, on August 6, 

2009. 

Dorenda D. Baker, 

Director, Aircraft Certification Service, Office 

of Aviation Safety. 

[FR Doc. E9–19350 Filed 8–14–09; 8:45 am] 

BILLING CODE 4910–13–P 


srobinson on DSKHWCL6B1PROD with PROPOSALS2