Document ID: FAA-2009-0738-0022
Agency: faa
Document Type: Rule
Title: Certification of Part 23 Turbofan- and Turbojet-Powered Airplanes and Miscellaneous Amendments
Posted Date: 2011-12-02T05:00Z

[Federal Register Volume 76, Number 232 (Friday, December 2, 2011)]
[Rules and Regulations]
[Pages 75736-75769]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-30412]

[[Page 75735]]

Vol. 76

Friday,

No. 232

December 2, 2011

Part IV

Department of Transportation

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Federal Aviation Administration

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14 CFR Part 23

Certification of Part 23 Turbofan- and Turbojet-Powered Airplanes and 
Miscellaneous Amendments; Final Rule

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

[[Page 75736]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. FAA-2009-0738; Amendment No. 23-62]
RIN 2120-AJ22

Certification of Part 23 Turbofan- and Turbojet-Powered Airplanes 
and Miscellaneous Amendments

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: This action enhances safety by amending the applicable 
standards for part 23 turbofan- and turbojet-powered airplanes--which 
are commonly referred to as ``part 23 jets,'' or ``jets''--as well as 
turbopropeller-driven and reciprocating-engine airplanes, to reflect 
the current needs of industry, accommodate future trends, address 
emerging technologies, and provide for future airplane operations. This 
action is necessary to eliminate the current workload of processing 
exemptions, special conditions, and equivalent level of safety findings 
necessary to certificate jets. The effect of the changes will: Enhance 
safety by requiring additional battery endurance requirements; increase 
the climb gradient performance for certain part 23 airplanes; 
standardize and simplify the certification of jets; clarify areas of 
frequent non-standardization and misinterpretation, particularly for 
electronic equipment and system certification; and codify existing 
certification requirements in special conditions for jets that 
incorporate new technologies.

DATES: These amendments become effective January 31, 2012.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning 
this final rule, contact Pat Mullen, Regulations and Policy, ACE-111, 
Federal Aviation Administration, 901 Locust Street, Kansas City, MO 
64106; telephone: (816) 329-4111; facsimile: (816) 329-4090; email: 
pat.mullen@faa.gov. For legal questions concerning this final rule, 
contact Mary Ellen Loftus, ACE-7, Federal Aviation Administration, 901 
Locust Street, Kansas City, MO 64106; telephone: (816) 329-3764; email: 
mary.ellen.loftus@faa.gov.

SUPPLEMENTARY INFORMATION:

Authority for This Rulemaking

    The FAA's authority to issue rules on aviation safety is found in 
Title 49 of the United States Code. Subtitle I, Section 106 describes 
the authority of the FAA Administrator. Subtitle VII, Aviation Programs 
describes in more detail the scope of the agency's authority. This 
rulemaking is promulgated under the authority described in Subtitle 
VII, Part A, Subpart III, Section 44701. Under that section, the FAA is 
charged with promoting safe flight of civil airplanes in air commerce 
by prescribing minimum standards required in the interest of safety for 
the design and performance of airplanes. This regulation is within the 
scope of that authority because it prescribes new safety standards for 
the design of normal, utility, acrobatic, and commuter category 
airplanes.

Table of Contents

I. Background
    A. Aviation Rulemaking Committee (ARC) Recommendations
    B. Summary of the Notice of Proposed Rulemaking
    C. Summary of the Final Rule
    D. Summary of the Comments
II. Discussion of the Final Rule
    A. 14 CFR Part 1: Clarifying Power and Engine Definitions
    B. Expanding Commuter Category To Include Turbojets
    C. Performance, Flight Characteristics, and Other Design 
Considerations
    D. Structural Considerations for Crashworthiness and High-
Altitude Operations
    E. Powerplant and Operational Considerations
    F. General Fire Protection and Flammability Standards for 
Insulation Materials
    G. Additional Powerplant and Operational Considerations
    H. Additional Powerplant Fire Protection and Flammability 
Standards
    I. Avionics, Systems, and Equipment Changes
    J. Placards, Operating Limitations, and Information
    K. Test Procedures and Appendices
III. Regulatory Analyses

I. Background

A. Aviation Rulemaking Committee (ARC) Recommendations

    On February 3, 2003, we published a notice announcing the creation 
of the part 125/135 Aviation Rulemaking Committee (68 FR 5488). The ARC 
completed its work in 2005 and submitted its recommendations to the FAA 
for safety standards applicable to part 23 turbojets. The ARC 
recommended modifying forty-one 14 CFR part 23 sections as a result of 
its review of these areas. Those documents may be reviewed in the 
docket for this final rule.
    The safety standards are to reflect the current industry trends, 
emerging technologies and operations under parts 125 and 135, and 
associated regulations. The ARC also reviewed the existing part 23 
certification requirements and the accident history of light piston-
powered, multiengine airplanes up through small turbojets used 
privately and for business purposes. In addition, the ARC reviewed the 
special conditions applied to part 23 turbojets.
    Based on those ARC recommendations, the FAA's intent is to enhance 
safety and to codify standards consistent with the level of safety 
currently required through special conditions. We compared the special 
conditions applied to part 23 turbojets, as well as several additional 
proposed part 23 changes, with the ARC's recommendations. With few 
exceptions, the ARC recommendations validated the FAA's long-held 
approach to certification of part 23 turbojets.
    The ARC did not want to impose commuter category takeoff speeds for 
turbojets weighing more than 6,000 pounds, nor did the ARC want to 
impose more stringent requirements for one-engine inoperative (OEI) 
climb performance than those established for similar-sized piston-
powered and turboprop, multiengine airplanes. The FAA ultimately 
accepted thirty-nine of the forty-one ARC recommendations and developed 
the proposed rulemaking in accordance with them. The two 
recommendations we disagreed with would have lowered the standards 
previously applied through special conditions.

B. Summary of the Notice of Proposed Rulemaking

    The FAA issued the notice of proposed rulemaking (NPRM), 
``Certification of Turbojets,'' on August 6, 2009 and published it for 
public comment on August 17, 2009 (74 FR 41556). The comment period for 
the NPRM closed on December 16, 2009 after a one-month extension.
    The FAA proposed the adoption of 67 new or revised amendments in 
the NPRM. The amendments were proposed to codify previous certification 
activity.

C. Summary of the Final Rule

    This final rule adopts 59 of the 67 proposed amendments. We have 
also amended Sec. Sec.  23.65 and 23.1431 in this final rule based on 
comments received. Changes to Sec.  23.65 make it consistent with the 
changes made to Sec.  23.63. Editorial changes to Sec.  23.1431 are 
based on paragraph designation changes to Sec.  23.1309.
    This final rule mainly levies new regulations for part 23 jets. 
These new

[[Page 75737]]

regulations generally fall into the following categories:

 Airplane flight performance and stability
 Airplane structural and cabin environment
 Airplane avionics systems and electrical equipment
 Powerplant considerations
 Flammability standards

    The majority of this final rule allows manufacturers of jets to 
achieve product certification without the numerous special conditions, 
equivalent level of safety (ELOS) findings, and exemptions previously 
required to certificate these products. Therefore, this final rule 
reduces the certification burden on the applicant and allows the FAA to 
focus resources on other safety-critical items. In addition, this final 
rule enhances safety by requiring additional battery endurance 
requirements and increasing the climb gradient performance for certain 
part 23 airplanes.

D. Summary of the Comments

    The FAA received 244 substantive comments from 14 commenters. All 
of the commenters generally supported the proposed changes. The 
comments included suggested changes, which are discussed more fully 
below in Section II, Discussion of the Final Rule.
    The FAA received no comments on the following sections, and they 
are adopted as proposed or with minor editorial changes:

 23.77, Balked landing
 23.853(d)(2), Passenger and crew compartment interiors
 23.1303(c), Flight and navigation instruments
 23.1445, Oxygen distribution system
 23.1447, Equipment standards for oxygen dispensing units
 23.1545, Airspeed indicator
 23.1555, Control markings
 23.1559, Operating limitations placard
 23.1563, Airspeed placards
 23.1567, Flight maneuver placard

    The FAA received comments from manufacturers, foreign aviation 
authorities, and industry associations. No commenters recommended 
withdrawing the NPRM. Most of the commenters provided suggestions for 
improvement or requested clarification of specific proposed amendments. 
Some commenters recommended that several proposed amendments (or 
portions of them) not be adopted. However, objection to one proposed 
amendment did not equate to overall objection to the NPRM.
    The following areas are the key concerns expressed by industry:

 Mandating software and complex hardware development assurance 
levels
 Requirement for electronic engine controls to meet the 
requirements of Sec.  23.1309 ``Equipment, systems and installations''
 Subpart B, Flight, and Subpart G, Operating Limitations and 
Information
 Requirement for ``two shot'' fire extinguishing systems for 
engines embedded within the fuselage
 Codifying high-altitude operations
 Requirements for electronic displays in part 23 airplanes
 Part 1 definitions (Sec.  1.1)

    The FAA also received comments regarding FAA policy, means of 
compliance, and suggested changes to advisory circulars and regulations 
not included in the NPRM. These comments are considered to be beyond 
the scope of this rulemaking effort. No further discussion of them 
occurs in this final rule.

II. Discussion of the Final Rule

A. 14 CFR Part 1: Clarifying Power and Engine Definitions

    The FAA proposed to amend Sec.  1.1 definitions for ``rated takeoff 
power,'' ``rated takeoff thrust,'' ``turbine engine,'' ``turbojet 
engine,'' and ``turboprop engine.'' Defining engine-specific terms was 
proposed to clarify the new requirements in part 23. Communications 
between the FAA and members of industry indicated a need to define 
those terms. These communications were mainly based on current part 1 
definitions for ``rated takeoff power'' and ``rated takeoff thrust,'' 
which currently limit the use of power and thrust ratings to no more 
than five minutes for takeoff operation.
    The FAA received comments from Rolls Royce, Transport Canada, 
General Electric (GE), and the European Aviation Safety Agency (EASA) 
objecting to the proposed definitions. The FAA agrees with the 
commenters that ``rated takeoff power,'' ``rated takeoff thrust,'' 
``turbine engine,'' ``turbojet engine,'' and ``turboprop engine'' are 
not used consistently in Title 14, Code of Federal Regulations (14 
CFR).
    Defining engine types--whether turbine-powered (turbine), turbojet-
powered (turbojet), or turbopropeller-driven (turboprop)--is 
unnecessary because they are commonly understood by those within 
industry. However, the commenters make a valid point regarding changes 
to the definitions for ``rated takeoff power'' and ``rated takeoff 
thrust.'' These terms may not necessarily be accepted for use in part 
25, and as such, should not be defined under Sec.  1.1.
    The Engine and Propeller Directorate is currently working to 
establish common definitions for ``rated takeoff power'' and ``rated 
takeoff thrust'' that would apply to both part 23 and part 25 
airplanes. The proposals to add these definitions are withdrawn to 
allow the Engine and Propeller Directorate time to complete its work on 
this effort.

B. Expanding Commuter Category to Include Jets

    The FAA proposed to revise Sec.  23.3 to codify the current FAA 
practice of certificating multiengine jets weighing up to and including 
19,000 pounds under part 23 in the commuter category. Prior amendments 
to part 23 limited Sec.  23.3 commuter category to propeller-driven, 
multiengine airplanes weighing no more than 19,000 pounds. However, the 
FAA issued exemptions to allow jets weighing more than 12,500 pounds to 
be certificated under part 23, commuter category.
    The FAA received comments from Transport Canada and EASA. Transport 
Canada proposed that jets with seating capacity of 10 or more 
(excluding pilot seats), or maximum certificated take-off weight of 
more than 12,500 pounds, continue to be certificated using part 25 
transport category requirements in Subpart B: Performance. EASA 
suggested the rule pertain to ``high performance'' rather than 
``multiengine'' airplanes.
    The FAA did not adopt either comment. Transport Canada's comment 
was not adopted because part 23, Subpart B has been shown to be an 
acceptable means of compliance for airplanes weighing up to 19,000 
pounds. This final rule retains that weight limit. EASA's comment was 
not adopted because ``high performance'' is an undefined, subjective 
term relative to airplane certification. Therefore, Sec.  23.3 is 
adopted as proposed.

C. Performance, Flight Characteristics, and Other Design Considerations

1. Performance
    The FAA proposed to incorporate in part 23 the current special 
conditions approach for jets weighing more than 6,000 pounds by 
applying most commuter category performance requirements. The proposed 
revisions to Sec.  23.45 would apply the commuter category performance 
requirements for the normal, utility, and acrobatic categories to 
multiengine jets weighing more than 6,000 pounds.
    As a general matter, several commenters recommended replacing

[[Page 75738]]

the proposed propulsion-based criteria with performance-based criteria. 
The FAA agrees, as indicated in the Small Airplane Directorate's 
Certification Process Study from 2009 which recommends revising part 23 
based on airplane performance and complexity versus propulsion and 
weight. However, amending part 23 to a performance-based standard is a 
substantially larger initiative than this rulemaking effort.
    During rulemaking discussions, the ARC decided that applying the 
commuter category takeoff performance requirements in proposed 
revisions to Sec. Sec.  23.51 through 23.61 would include restrictions 
that could become a takeoff weight limitation for operations. The 
concern was that these requirements would be too restrictive for part 
91 operations.
    The FAA disagreed with the ARC concerning multiengine jets weighing 
more than 6,000 pounds. The FAA has several decades of experience 
applying existing special conditions to part 23 jets. The performance 
requirements for these jets have proven successful for part 91 
operations and are necessary to maintain the existing level of safety.
    We received three comments regarding this proposal. EASA supported 
the changes and suggested requirements be extended to all jets, not 
just to those weighing more than 6,000 pounds. Diamond Aircraft 
(Diamond) asked why this rule did not apply to turboprops and piston-
powered airplanes. Transport Canada proposed that the all-engines-
operating accelerate-stop distance be determined in addition to the 
one-engine inoperative (OEI) distance, and the greater of the two be 
used as the accelerate-stop distance.
    Again, the Small Airplane Directorate's Certification Process Study 
from 2009 recommends revising part 23 based on performance and 
complexity versus propulsion and weight. We have not yet proposed to 
completely rewrite part 23, and doing so would be beyond the scope of 
this rulemaking. Accordingly, no change was made to the proposal in 
this final rule, except to change the word ``turbojet'' to ``jet'' 
wherever appropriate in this final rule.
    The FAA proposed revisions to Sec. Sec.  23.63 and 23.67 to enhance 
safety by increasing the OEI climb gradient performance for multiengine 
piston-powered airplanes weighing more than 6,000 pounds and for all 
multiengine turbines. We proposed no change to the current 2 percent 
OEI climb gradient that has been consistently applied via special 
condition for multiengine jets weighing more than 6,000 pounds.
    We proposed to revise the OEI climb gradient requirements to 
require a 1 percent OEI climb gradient for all multiengine turboprops 
and multiengine piston-powered airplanes weighing more than 6,000 
pounds. We did so because of the similarity in how these two types of 
airplanes are used. Multiengine jets weighing 6,000 pounds or less will 
be required to meet an OEI climb gradient of 1.2 percent with this 
revision.
    The FAA has revised Sec.  23.63(c) and (d), and Sec.  23.67(b) and 
(c) to reflect these changes to the climb gradient requirements. The 
FAA also made a minor editorial change to replace ``turbojet engine-
powered'' with ``jet'' wherever appropriate in this final rule to 
simplify the term. Table 1 summarizes those changes:

           Table 1--One-Engine Inoperative (OEI) Climb Requirements to 400 Feet Above Ground Level AGL
----------------------------------------------------------------------------------------------------------------
                                                                                 ARC's         FAA's position in
           Multiengine category                     Current rule            recommendation        final rule
                                                                               (percent)           (percent)
----------------------------------------------------------------------------------------------------------------
Pistons > 6,000 lbs.......................  Measurably positive.........                 1.0                 1.0
Turboprops <= 6,000 lbs...................  Measurably positive.........                 1.0                 1.0
Turboprops > 6,000 lbs....................  Measurably positive.........                 1.0                 1.0
Jets <= 6,000 lbs.........................  Measurably positive.........                 1.0                 1.2
Jets > 6,000 lbs..........................  2.0% imposed through special                 1.0                 2.0
                                             conditions.
----------------------------------------------------------------------------------------------------------------

    The FAA received comments on Sec. Sec.  23.63, 23.65, and 23.67 
from Transport Canada, Hawker Beechcraft, and Diamond. Transport Canada 
stated that the proposed Sec.  23.63 would conflict with the existing 
Sec.  23.65. The FAA has accordingly revised Sec.  23.65 for 
consistency. Hawker Beechcraft stated that the change from ``must be 
measurably positive'' to ``may be no less than 1 percent'' could reduce 
takeoff payload by a maximum of 900 pounds. This would limit the 
utility of a normal category turboprop under high-hot conditions with 
takeoff flaps. The FAA understands that leveling the turboprop 
requirements with certain jets will cause a loss of utility and market 
disadvantage. However, given similar missions (many in revenue 
service), turboprops should be held to a performance standard similar 
to that for jets. The FAA reviewed the current service history safety 
data for these airplanes. Based on this data, the FAA only required 
half the single-engine climb requirements of multiengine jets.
    Diamond stated that this makes sense to a certain degree if the 
reasoning behind it is that turbines are capable of better performance 
than piston-powered airplanes. However, Diamond asked if there is a 
need to require compensating features if the airplane cannot meet a 
reasonable climb gradient. Diamond also asked why the FAA would change 
to a safer engine type if history has not shown there to be a problem 
with the current engine type. Diamond further stated that this 
requirement should be consistent with those for turbines, with no 
distinction between jets and turboprops. The FAA partially agreed and, 
as stated above, adopted an OEI climb gradient of 1 percent.
    The FAA received a comment from GE on the economic benefit of 
improved climb performance. GE stated that the improved climb 
performance is not a new requirement, and it is currently imposed by 
special condition. Since that special condition is not changing--it is 
now only being levied by this final rule--GE asked how a safety benefit 
can be credited to the rule.
    The FAA believes that adding this special condition as a 
requirement in part 23 will not only have a safety benefit, but it will 
also enhance our efforts toward continued operational safety. Special 
conditions are aircraft-specific and have not been issued for every 
part 23 airplane. Section 23.67 (and Sec.  23.77, which was adopted 
without change) addresses the additional climb performance for all part 
23 turbojets and turboprops. The additional climb performance 
requirements will apply to all new part 23 turboprops and part 23 
turbojets under 6,000 pounds, thereby increasing the operational safety 
of those newly certificated airplanes.
    In addition, special conditions increase paperwork and workload for 
FAA and industry. Also, they create uncertainty for the manufacturer 
during

[[Page 75739]]

design. By incorporating the improved climb performance into part 23, 
special condition paperwork will be reduced and, in effect, will allow 
FAA and industry resource leveraging towards other safety-critical 
endeavors in our goal of continued operational safety.
    In developing cost estimates for the NPRM, the FAA contacted 
members of the ARC to determine when and if special conditions were 
voluntarily accepted by industry. When a special condition is 
voluntarily accepted by industry, the FAA does not include the special 
condition(s) cost in the regulatory impact assessment (RIA). When 
industry informs the FAA that a special condition will impose costs on 
industry, as do Sec. Sec.  23.67 and 23.77, the FAA estimates the 
incremental cost between the current and final rule.
    The FAA proposed to correct a reference error to a velocity term in 
Sec.  23.73. Maximum landing configuration stall speed (VSO) 
was changed to specified flap configuration stall speed 
(VS1). VSO is not applicable to other flap 
configurations. The reference landing approach speed (VREF) 
is based on 1.3 times the VS1. The FAA proposed to amend the 
standards to address airplanes certificated under part 23 that may have 
more than one landing flap setting. Additionally, the FAA proposed to 
include multiengine jets weighing more than 6,000 pounds in the 
commuter category requirements.
    The FAA received one comment. Diamond stated that the distinction 
between jet engines and other engine types may not be appropriate. It 
suggested the requirement for a higher level of safety be related to 
performance, not to engine type. As stated earlier, the FAA has 
determined that amending part 23 to a performance-based standard is a 
substantially larger initiative and beyond the scope of this rulemaking 
effort.
2. Flight Characteristics
    In Sec.  23.175(b), the FAA proposed to define the maximum speed 
for stability characteristics (VFC/MFC). The term 
VFC/MFC was added to part 23 in the last large-
scale revision to Subpart B, but the definition was inadvertently 
omitted.
    EASA commented on multiple proposed sections that it applies a 
special condition for high-speed characteristics that are not included 
in our proposal. EASA's comments suggested these sections be drafted as 
a performance-based standard. However, amending part 23 to a 
performance-based standard is a substantially larger initiative than 
this rulemaking effort.
    The FAA also received comments from Transport Canada and Cessna 
regarding flight characteristics. Both commenters recommended that we 
include the definition of VFC/MFC in Sec.  23.253 
for consistency with part 25. The FAA agrees and has relocated the 
definition for it from Sec.  23.175 to Sec.  23.253.
    The FAA proposed revisions to Sec.  23.177 that would have 
clarified the specific speed limitations to include jets. The proposed 
speed limitations also included specific criteria (``VFE, 
VLE, VNO or VFC/MFC as 
appropriate'' as defined in Part 1).
    The FAA proposed to relax the stability requirements in Sec.  
23.181 for airplanes operating above 18,000. The original requirements 
were developed for small airplanes typically operated under 18,000 feet 
and not equipped with yaw dampers. The existing requirement is still 
appropriate for low-altitude operations, such as for approaches. 
However, the existing requirement is not appropriate for larger 
airplanes that typically use yaw dampers and fly at altitudes above 
18,000 feet. In fact, the FAA has issued multiple ELOS findings for 
most certificated part 23 jets because such findings were appropriate 
for high-altitude, high-speed operations.
    The FAA received comments from EASA, Cessna, and Emivest. EASA 
commented in multiple sections that it applies a special condition for 
high-speed characteristic not included in our proposal. EASA's comment 
suggests a performance-based standard. Amending part 23 to a 
performance-based standard is a substantially larger initiative than 
this rulemaking effort.
    Cessna suggested Sec.  23.181 include a similar definition to the 
revised Sec.  23.177. The FAA agrees with Cessna's comment and added 
that definition to Sec.  23.181.
    Emivest recommended that part 23 allow the lower standard found in 
part 25 for flight above 18,000 feet. The FAA disagrees with this 
recommendation. Part 23 airplanes are frequently flown by a single 
pilot and operated under part 91. Single pilots operating part 23 
airplanes may not necessarily have the same experience level as part 25 
airplane pilots. Therefore, the stability and control requirements in 
part 23 will remain higher than in part 25.
    We proposed revisions to the stall requirements in Sec. Sec.  
23.201 and 23.203 to include jets and a new generation of part 23 
airplanes with high-power and high-altitude capability.
    The proposed revisions included:
     Incorporating additional configurations for all part 23 
airplanes;
     Clarifying flap and gear position as appropriate for the 
altitude and flight phase;
     Relaxing the roll-off requirements for high-altitude 
stalls; and
     Defining what is meant by ``extreme nose-high attitudes.''
    The FAA received comments from the General Aviation Manufacturers 
Association (GAMA) and Emivest. GAMA stated the requirement for the 
demonstration of control during entry and recovery from wings level 
stall is unnecessary above 1.5 VS1 instead of 1.6 
VS1, as this requirement matches the requirements applicable 
to part 25 airplanes. The FAA agrees and has made the necessary change 
to be consistent with the requirements for part 23 jets.
    Emivest recommended the FAA allow the lower handling characteristic 
standards from part 25, specifically being able to control rolling from 
15 to 20 degrees of roll. The FAA does not believe that this is 
appropriate for all altitudes. Parts 23 and 25 still have a 
considerable number of stall/departure accidents at low altitudes, even 
with stall barrier devices. The FAA is moving part 23 towards even more 
benign stall characteristics and additional stall protection systems.
    The FAA determined that relieving the controllability requirements 
in Sec.  23.201 across the entire altitude capability would move part 
23 in the wrong direction--inconsistent with current stall 
requirements. Considering that most stall accidents occur at low 
altitudes, this revision would relax the stall handling characteristic 
roll requirement to 25 degrees for stalls at or above 25,000 feet. We 
believe this is an acceptable action for this flight regimen for the 
class of airplane operating at or above 25,000 feet.
    The FAA proposed to incorporate provisions from Sec. Sec.  
25.251(d) and (e) into Sec.  23.251 while limiting the requirements to 
airplanes that fly over 25,000 feet or that have a Mach Dive Speed 
(MD) faster than Mach (M) 0.6. The proposed revision also 
included the use of VDF/MDF, as referenced in 
part 23 jet special conditions.
    The FAA received similar comments from Cirrus and Transport Canada. 
Cirrus stated that Sec.  23.251(b) and (c) use the term ``perceptible 
buffeting,'' which is a subjective term. Cirrus requested a concise 
term to differentiate ``normal vibration'' from ``perceptible 
buffeting,'' or a standard definition of ``perceptible buffeting.'' The 
FAA will address this comment in an advisory circular, which we believe 
is the appropriate place to address it.

[[Page 75740]]

    Transport Canada stated that the use of operational speeds is 
considered more appropriate than using a design speed as criteria. The 
FAA understands the commenter's point. For this situation, however, the 
FAA believes the part 23 speed rationale should parallel the rationale 
in part 25 for consistency in our decisions for continued aviation 
safety.
    The FAA revised Sec.  23.253(b) to add the use of demonstrated 
flight diving speed (VDF/MDF) as applicable, 
consistent with standards in Sec.  25.253. The FAA also moved the 
proposed definition for VFC/MFC from Sec.  23.175 
to this section as paragraph (d).
    The FAA proposed adding Sec.  23.255 to include new requirements 
that consider potential high-speed Mach effects for airplanes with 
MD greater than M 0.6. The FAA proposed these requirements, 
which came from part 25, for airplanes that incorporate a trimmable 
horizontal stabilizer. This decision was based on the positive service 
history with the existing fleet of part 23 jets designed with 
conventional horizontal tails and those that use trimmable elevators. 
Airplanes that experienced upset incidents involving out-of-trim 
conditions were part 25 certificated airplanes and designed with a 
trimmable horizontal stabilizer.
    The FAA received a comment from Transport Canada, stating that this 
requirement should apply to all horizontal tail configurations as 
required for transport category airplanes. The FAA disagrees with 
Transport Canada. The high-performance airplanes that will be 
certificated under part 23 are similar to those that have established a 
positive service history using similar regulations; therefore, this 
final rule has not been changed as a result of this comment.

D. Structural Considerations for Crashworthiness and High-Altitude 
Operations

1. Design and Construction
    The FAA proposed changes to Sec.  23.561 to address structural 
requirements for engines contained within the fuselage and located 
behind the passenger cabin. The FAA proposed these changes to: (1) Add 
structural requirements to single-engine jets with centerline engines 
embedded in the fuselage, and (2) minimize the likelihood of the engine 
breaching the passenger compartment in the event of an emergency 
landing. The proposal would have reduced the potential for the engine 
to separate from its mounts under forward-acting crash loads and 
subsequently intrude into the passenger compartment (i.e., cabin).
    The FAA received several comments on this proposed change. EASA 
suggested the proposed rule should be expanded to include any engine 
mounted inside the fuselage and aft of the cabin, not just turbojet 
engines. The FAA agrees with EASA. Any engine mounted in this type of 
configuration may be a hazard to cabin occupants in the event of an 
emergency landing, so the regulation should not be limited to turbojet 
engines. The proposed amendment has been modified to capture this 
comment.
    Transport Canada stated that the proposed load factors should be 
adjusted upward if the VS0 of the airplane exceeds 61 knots. 
The FAA disagrees with Transport Canada since the proposed regulation 
would require the engine to be retained at 18 g in combination with 
maximum takeoff thrust. This approach is reasonable for engine 
retention.
    Transport Canada also stated that the attached accessories need not 
be required to withstand the added load of maximum engine takeoff 
thrust since accessories do not react to engine thrust loads. The FAA 
disagrees with this comment. While engine accessories should not 
directly react to engine thrust loads, engine accessories impart a load 
to their mounting structure. This load is typically highest when the 
engine is producing maximum takeoff thrust. The intent of this rule is 
to ensure the engine and its accessories do not penetrate the cabin in 
an emergency landing.
    Transport Canada further stated that proposed Sec.  
23.561(e)(1)(ii), which in the relevant part states ``to deflect the 
engine'' may be too limited. The commenter suggested there are other 
methods an airplane designer may propose, such as an energy-absorbing 
bulkhead or barrier. We agree, and by adopting this comment, the rule 
will be more performance-based and preclude dictation of the airframe 
design. The FAA has changed this final rule accordingly.
    The FAA proposed changes to Sec.  23.562 to require dynamic seat 
testing for commuter category jets. The FAA also proposed changes to 
the Head Injury Criteria (HIC) calculation in Sec.  23.562 to be 
consistent with the HIC calculation contained in Sec.  25.562.
    Our intent with the proposed rule was to codify a requirement that 
has become industry practice. All manufacturers of those recently 
certificated commuter category jets have agreed to comply with Sec.  
23.562. It was not our intent to include commuter category propeller-
driven airplanes in Sec.  23.562 in light of the rulemaking history 
associated with that effort.\1\ The FAA has decided against adding 
commuter category propeller-driven airplanes to Sec.  23.562 at this 
time. The FAA reserves the right, however, to reconsider this position 
in the future should adverse service history suggest changes are 
necessary.
---------------------------------------------------------------------------

    \1\ The FAA provided a history of the previous rulemaking effort 
in the NPRM. 74 FR 41522.
---------------------------------------------------------------------------

    In addition, the FAA received comments from several organizations 
indicating a mistake in the proposed HIC calculation. The commenters 
stated that the proposed definition of ``a(t)'' would require 
calculating HIC for the entire head acceleration time, not just for the 
time of impact with interior components. The FAA agrees the proposed 
rule did not specify the word ``strike'' when defining ``a(t)'' as the 
total acceleration versus the time curve for a head strike. The FAA has 
made the necessary changes to the definition of ``a(t)'' in this final 
rule so it is clear that HIC is calculated for the head strike only.
    The NPRM included new sections in Sec. Sec.  23.571, 23.573, and 
23.574, which noted additional requirements referencing the new high 
altitude requirements of Sec.  23.841(e). These additional requirements 
included the establishment of a Limit of Validity (LOV), as well as 
additional test requirements. Several commenters, including Cessna and 
GAMA, objected to the LOV concept due to the burden it could place on 
applicants. Upon consideration of these comments the FAA agrees we need 
additional time to consider the need for LOV. Therefore, we 
consolidated the requirements into Sec.  23.571(d) and removed the 
reference to Sec.  23.841. Proposed Sec.  23.841(e), which contained 
the LOV and additional test requirements, has been withdrawn.
    Section 23.571(d) still requires the damage tolerance option under 
Sec.  23.573 to be used on airplanes that exceed 41,000 feet. Section 
23.571(d) will also require that damage tolerance be used to evaluate 
structure for operations above 41,000 feet on all airplanes except 
commuter category. Commuter category airplanes are already required to 
use damage tolerance under Sec.  23.574. The FAA has modified Sec.  
23.571 as discussed and withdrawn the proposed revisions to Sec. Sec.  
23.573 and 23.574.
    In addition, GE stated it would be difficult to comply with the 
proposed Sec.  23.841, given all of the exemptions granted for this 
rule in the past. The FAA disagrees with this comment, but GE is 
correct that a number of exemptions have been granted.

[[Page 75741]]

However, all but one of the exemptions were for part 25 airplanes. This 
single part 23 airplane exemption dealt with the method of compliance 
for this rule. (See Exemption No. 5223; also, a copy of this exemption 
will be placed in the docket for this rulemaking.)
    As noted above, the proposed rule has been revised, and previous 
part 25 exemptions are irrelevant to the subject part 23 airplanes. 
Several jets have successfully met depressurization profiles, thereby 
meeting appropriate part 23 certification requirements.
    The FAA proposed to clarify the use of either the MD or 
the Dive Velocity (VD) in Sec.  23.629, whichever is 
appropriate, for jets. As dive speeds increase with high performance 
airplanes, the compressibility effects of the air become more 
significant; therefore, it is more appropriate to refer to 
MD instead of VD. Proposed changes would have 
also allowed the use of a ``demonstrated'' flight dive speed 
(VDF/MDF) instead of the theoretical speeds 
(VD/MD) when flight flutter testing jets. Using a 
demonstrated speed, in lieu of a theoretical speed, can relieve some 
compliance burden when an airplane is unable to attain those 
theoretical dive speeds during the test phase of an airplane 
certification program.
    Cessna stated that the FAA was attempting to align the part 23 
small airplane flutter requirements with those of part 25 for transport 
category airplanes. The FAA does not agree with this summary of the 
change. While the change is similar to certain transport category 
requirements, there was no decision in this case to make this part 23 
requirement identical to part 25 requirements. The FAA seeks only to 
establish a category-appropriate rule for jets which balances many 
factors; those factors include risk management, safety, and cost.
    Cessna stated that in one paragraph the FAA only made the change to 
add the Mach dive speed designation, but did not include the option for 
the demonstrated flight speeds. The FAA agrees with Cessna. It was 
inadvertently omitted from the proposed rule language. The FAA adopted 
that change in the final rule.
    Cessna further stated the proposal implied that the flutter 
analysis need only be performed to the demonstrated flight speed. The 
FAA agrees the wording was misleading and ambiguous. Therefore, the 
proposed language is revised to clarify that the flutter analysis must 
be performed to 20 percent above the design dive speed or 20 percent 
above the design Mach dive speed, whichever is appropriate. 
Additionally, Sec.  23.629 is revised to clarify that the 20 percent 
margin above the design dive speed need not go above Mach 1.0, as this 
unnecessarily complicates the analysis.
2. Other Design Considerations
    Proposed revisions to Sec.  23.703 introductory text and paragraph 
(b) would have added takeoff warning system requirements to all 
airplanes weighing more than 6,000 pounds and to all jets. The 
definition of an unsafe condition, in this case, is the inability to 
rotate or prevent an immediate stall after rotation. High temporary 
control forces that can be quickly ``trimmed out'' would not 
necessarily be considered unsafe.
    The FAA received two comments. EASA suggested the rule did not 
address all devices for a safe takeoff. Diamond asked why this rule did 
not apply to turboprops and piston-powered airplanes.
    Parking brakes and antiskid devices are optional installations and 
cannot be required by this rule; but if installed, optional 
installations can be included in the determination of an unsafe takeoff 
condition. Also, this rule applies to all airplanes weighing more than 
6,000 pounds and to jets of any weight. Therefore, turboprops and 
piston-powered airplanes weighing more than 6,000 pounds are included. 
The FAA inadvertently modified Sec.  23.703(b) in the NPRM. Our intent 
was to add a new section, Sec.  23.703(c). The FAA is adopting Sec.  
23.703(c) as originally intended and with a minor editorial change.
    The FAA changed the rejected takeoff requirements in Sec.  23.735, 
which were previously only for commuter category airplanes, to be 
applicable for all multiengine jets weighing more than 6,000 pounds. 
The higher takeoff speeds and distances for these airplanes make the 
ability to stop in a specified distance a safety issue.
    Two commenters suggested adding similar rejected requirements from 
part 25. Adding these part 25 requirements, however, was not part of 
the NPRM. In this case, the part 25 requirements are too stringent for 
part 23 airplanes. We cannot justify those more stringent requirements 
based on our current service history.

E. Powerplant and Operational Considerations

    Previous amendments to Sec.  23.777 standardized the height and 
location of powerplant controls because pilots may become confused and 
use the wrong controls on propeller-driven airplanes. However, previous 
amendments did not include single-power levers (which are typical for 
electronically-controlled engines). The FAA made an ELOS finding for 
each airplane program that included a single-power lever. Revised 
paragraph (d) in Sec.  23.777 incorporates the ELOS language.
    The FAA received one comment that the requirement for power 
(thrust) levers should be easily distinguishable for human factor 
considerations instead of one inch higher than mixture and propeller 
levers. The FAA agrees with this comment and revised the rule to delete 
the one-inch requirement and changed the wording to easily distinguish 
the power levers from other controls.
    The FAA proposed to provide an alternative to meeting the 
requirement for an emergency exit above the waterline on both sides of 
the cabin for multiengine airplanes. The proposed change to Sec.  
23.807 allows the placement of a water barrier in the main cabin 
doorway before the door is opened as a means to comply with the above 
waterline exit requirement. This barrier is above the waterline and 
slows the water inflow, thus allowing exit through the main cabin door 
in a ditched airplane. The FAA approved the use of this barrier as an 
alternative to the above waterline exit for several airplanes by 
issuing an ELOS finding.
    The FAA received two comments. Emivest stated the rule language 
would permit a main cabin door below the waterline to be approved as an 
emergency exit. Embraer stated a water barrier should be allowed 
regardless of whether the main cabin door is above the waterline since 
the determination of the waterline is undefined.
    The FAA disagrees with both comments. The new Sec.  23.807(e)(3) 
states ``may'' because the new paragraph is an option for paragraph 
(e)(2), which specifies an overhead exit if side exits cannot be above 
the waterline. Furthermore, buoyancy analysis is standard practice to 
determine the waterline of an airplane. There is no reason to provide a 
water barrier if the emergency exit is above the waterline. Therefore, 
no changes were made to the proposal in this final rule.
    The FAA proposed amending Sec.  23.831 by adding new paragraphs (c) 
and (d), which would include standards appropriate for airplanes 
operating at high altitudes beyond those included in part 23. The 
changes were intended to ensure that flight deck and cabin environments 
do not result in the crew's mental errors or physical exhaustion. Such 
an event would prevent the crew from successfully completing assigned 
tasks for continued safe flight and landing of an airplane. An 
applicant

[[Page 75742]]

may demonstrate compliance with paragraph (d) of this requirement if 
the applicant can show the flight deck crew's performance is not 
degraded.
    Several new part 23 jet certification programs include approval for 
operations at altitudes above 41,000 feet. Additionally, the FAA issued 
special conditions for operations up to 49,000 feet and changed rules 
for structures and the cabin environment to ensure structural integrity 
of the airplane at higher altitudes. The FAA also made rule changes to 
prevent exposure of the occupants to cabin pressure altitudes that 
could cause them physiological injury or prevent the flight crew from 
safely flying and landing the airplane.
    The FAA intended the requirement ``* * * must not affect crew 
performance so as to result in a hazardous condition * * *'' to mean 
the crew can reliably perform published and trained duties to complete 
a safe flight and landing. In the past, a person's ability to track and 
perform tasks was measured by crew performance; however, acceptable 
crew performance is limited to the procedures defined by the 
manufacturer or required by existing regulations. The FAA uses ``No 
occupant shall sustain permanent physiological harm'' to describe the 
requirement that occupants who may have required some form of 
assistance must be expected to return to their normal activities once 
treated.
    Cirrus and Transport Canada stated the proposal, as written, 
applied to all phases of flight, including slow speed phases. The 
proposal was intended to apply to flight above 41,000 feet. The final 
rule for paragraphs (c) and (d) is changed to state the paragraphs are 
applicable only for the cruise phase of flight above 41,000 feet.
    Diamond suggested the rule should apply to all pressurized 
airplanes, not just to jets. The intent of the proposal was for it to 
apply to airplanes that operate above 41,000 feet. The FAA is unaware 
of any turboprops or piston-powered airplanes that operate above 41,000 
feet. Special conditions would be applied to a turboprop or piston-
powered airplane with a maximum service ceiling above 41,000 feet.
    EASA stated two figures used for high-altitude airplanes, regarding 
the time temperature correlation, were not included. That oversight is 
corrected in this final rule.
    We proposed amending requirements in Sec.  23.841 to prevent 
exposure of the occupants to cabin pressure altitudes that could keep 
the flight crew from safely flying and landing the airplane, or cause 
permanent physiological injury to the occupants. The changes provide 
airworthiness standards that allow subsonic, pressurized jets to 
operate at their maximum achievable altitudes--the highest altitude an 
applicant can choose to demonstrate the effects to several occupant-
related items after decompression. The applicant must show that: (1) 
The flight crew would remain alert and be able to fly the airplane, (2) 
the cabin occupants are protected from the effects of hypoxia (i.e., 
deprivation of adequate oxygen supply), and (3) if some occupants do 
not receive supplemental oxygen, they are protected against permanent 
physiological harm.
    Several new part 23 jet certification programs include approval for 
operations at altitudes above 41,000 feet. Additionally, we issued 
special conditions for operations up to 49,000 feet. In this final 
rule, we changed rules for structures and the cabin environment to 
ensure structural integrity of the airplane at higher altitudes.
    Earlier amendments required the cabin pressure control system to 
maintain the cabin at an altitude of not more than 15,000 feet if any 
probable failure or malfunction in the pressurization system occurred. 
Cabin pressure control systems on part 23 airplanes frequently exhibit 
a slight overshoot above 15,000 feet cabin altitude before stabilizing 
below 15,000 feet. Existing technology for cabin pressure control 
systems on part 23 airplanes cannot prevent this momentary overshoot, 
which prevents strict compliance with the rule. The FAA granted ELOS 
findings for this characteristic because physiological data show that 
the brief duration of the overshoot has no significant effect on an 
airplane's occupants.
    Special conditions issued for part 23 jets to operate at altitudes 
above 41,000 feet are equivalent to the requirements in Sec.  25.841 
adopted in Amendment 25-87 (61 FR 28684, June 5, 1996). The amendment 
in this final rule modified Sec.  23.841 to include requirements for 
pressurized cabins previously covered only in special conditions. The 
special conditions required consideration of specific failures. Part 25 
incorporated reliability, probability, and damage tolerance concepts 
addressing other failures and methods of analysis after the issuance of 
the special conditions. Sections 23.571, 23.573, and 23.574 address the 
damage tolerance requirements. This final rule requires the use of 
these additional methods of analysis.
    Part 23 requires a warning of an excessive cabin altitude at 10,000 
feet. Part 23 does not adequately address operations at airfield 
elevations above 10,000 feet. Rather than disable the cabin altitude 
warning to prevent nuisance warnings, the FAA has issued ELOS findings 
allowing the warning altitude setting to be shifted above the maximum 
approved field elevation, not to exceed 15,000 feet. The FAA proposed 
to modify Sec.  23.841 to incorporate language from existing ELOS 
findings into the regulation.
    The FAA received nine comments on this proposal. Several commenters 
disagreed with the structure of the initial proposed rule, the use of 
the noted damage tolerance principles, and the general systems rule for 
pressurization at high altitude. While EASA supported establishment of 
a Limit of Validity (LOV) and additional testing, Cessna, Embraer, and 
GAMA disagreed with the implementation of these concepts, which are not 
currently used in part 23.
    In response to comments from GAMA and Embraer, the FAA changed 
paragraph (b)(6)(ii) to permit a single operation for high altitude 
takeoffs and landings. In response to a comment from GE, paragraph 
(c)(2) is changed to exclude improbable failures.
    In addition, ruptures must be limited to control pressurized cabin 
breeches. Rapid pressure loss at high altitudes may result in 
physiological damage to the occupants. Section 23.841 defines 
acceptable depressurization profiles in such an event, and the 
pressurized structure serves as a part of the system to ensure the 
minimum cabin pressure is maintained. To control the cabin pressure 
vessel breeches in the fuselage structure, the noted damage tolerance 
principles are used (specifically borrowing the process referenced in 
Sec.  23.573(a) or (b)).

F. General Fire Protection and Flammability Standards for Insulation 
Materials

    The FAA proposed upgrading flammability standards for thermal and 
acoustic insulation materials by adding a new Sec.  23.856. The 
previous standards did not realistically address situations where 
thermal or acoustic insulation materials may contribute to producing a 
fire. The changes are based on the requirements in Sec.  25.856(a) and 
part VI, Appendix F, which were adopted following accidents involving 
part 25 airplanes, such as the Swissair MD-11. The proposed new 
standards would enhance safety by reducing the incidence and severity 
of cabin fires, particularly those in inaccessible areas where thermal 
and acoustic insulation materials are installed.

[[Page 75743]]

    The proposed new standards also would include flammability tests 
and criteria that address flame propagation. They would apply to 
thermal/acoustic insulation material installed in the fuselage of part 
23 airplanes.
    Prior amendments focus almost exclusively on materials located in 
occupied compartments (Sec.  23.853) and cargo and baggage compartments 
(Sec.  23.855). The potential for an in-flight fire is not limited to 
those specific compartments. Thermal/acoustic insulation can be 
installed throughout the fuselage in other areas, such as electrical or 
electronic compartments or surrounding air ducts, where the potential 
also exists for materials to spread fire.
    Proposed Sec.  23.856 accounts for insulation installed within a 
specific compartment in areas the regulations might not otherwise cover 
and is applicable to all part 23 airplanes, regardless of size or 
passenger capacity. Advisory material describing test sample 
configurations to address design details (e.g., tapes and hook-and-loop 
fasteners) is available in DOT/FAA/AR-00/12, Aircraft Materials Fire 
Test Handbook, April 2000.
    Cessna stated this proposal should be limited to commuter category 
airplanes. The FAA disagrees because this hazard is not limited to 
commuter category airplanes. In addition, there has been a 
certification project to install this insulation in a normal category 
airplane.

G. Additional Powerplant and Operational Considerations

    We inadvertently proposed to add requirements to Sec.  23.903(b)(2) 
when we meant to propose a new paragraph (b)(3). This proposal was 
intended to protect passengers and maintain the ability for continued 
safe flight and landing following a fan disconnect event for fuselage-
embedded, jet-engine installations.
    The FAA received six comments on this proposed rule change. Cirrus 
favors avoiding the use of the ``embedded'' classification altogether; 
the FAA does not. The crux of Cirrus' position relates to the 
requirements for fire protection of embedded engines, and not 
protection against fan disconnect. Hawker Beechcraft, GE, and EASA 
commented on assessing the threat from fan disconnect questions as the 
means of compliance to this rule change.
    For each airplane with an embedded engine, the FAA will provide 
project-specific guidance for an acceptable means of compliance 
regarding fan-disconnect concerns. If the engine does not have a 
failure mode that results in a fan-disconnect event, then basic 
compliance would need to show the failure cannot occur. In this 
instance, no further showing of compliance would be required. Transport 
Canada supports the rule change.
    The FAA proposed adding a paragraph to Sec.  23.1141 to require 
electronic engine control systems to meet the equipment, systems, and 
installation standards of Sec.  23.1309. The FAA has applied this 
requirement to all digital engine control installations in part 23 
airplanes by special condition for over ten years. The proposed rule 
change for Sec.  23.1141 would have codified the requirements 
previously applied via special condition.
    The FAA received six comments on this proposed rule change. Most of 
the comments questioned the need for the specific application of Sec.  
23.1309 to electronic engine control systems. Diamond, GAMA, and Hawker 
Beechcraft stated that compliance was already required. Cessna stated 
there were similar requirements in Sec.  23.1141(e). GE stated there 
were no commensurate requirements in part 25, and that engine control 
was certificated in part 33. Transport Canada suggested the change 
should only address the electromagnetic environment and compatibility 
requirements, rather than all of Sec.  23.1309.
    The FAA has not directly adopted these comments. However, the 
comments highlighted the difficulties in using Sec.  23.1309 as the 
primary means by which to certificate electronic engine control system 
installation. There are conflicts between the guidance material for 
Sec.  23.1309 and propulsion system certification. One example is a 
single-engine turbine-powered airplane with a failure of the electronic 
engine control system which cannot meet the failure probability 
commensurate with the hazard. As a result, applicants have elected to 
declare a reduced hazard severity of a failure of the electronic engine 
control system. This is not the intent of Sec.  23.1309. The greater 
hazard severity should drive lower probability of failure, and the 
higher probability of failure should not drive the lower hazard 
severity.
    There is also a conflict between the hazard severity of a failure 
of an electronic engine control system and the required test levels for 
lightning and high intensity radiated frequency (HIRF). Testing to a 
level lower than required for a catastrophic failure results in a lower 
level of safety than the mechanical system it replaces. This is 
contrary to the intent of the certification requirements. As a result, 
the FAA decided to withdraw the proposed rule change and will continue 
to require the test levels via special conditions.
    We also proposed to expand the requirement in Sec.  23.1165(f) for 
all turbine engine installations in commuter category airplanes, as it 
is currently limited to turboprops. The revision to the rule covers all 
turbines in the commuter category and removes the propeller driven 
restriction. (The definition of commuter category is also changed in 
Sec.  23.3(d).)
    Transport Canada stated that the proposed rule conflicted with the 
gas turbine ignition systems for restarting an engine in flight, as 
required by Sec.  23.903(e)(3), (f) and (g). The FAA does not agree 
with this comment, as there is no conflict with the cited rules. 
Embraer suggested that the rule should be reworded to state ``* * * 
each turbine engine ignition system must be considered an essential 
electrical load.'' The FAA disagrees, as the suggested change does not 
change the substance of the rule. The proposal is adopted without 
change.

H. Additional Powerplant Fire Protection and Flammability Standards

    When the FAA initially introduced powerplant fire protection 
provisions in part 23, jet engines were not embedded in the fuselage, 
or in pylons on the aft fuselage, for airplanes certificated to part 23 
standards. Sections 23.1193, 23.1195, 23.1197, 23.1199, and 23.1201 
added fire protection requirements for commuter category airplanes.
    Manufacturers also provide fire prevention through minimizing the 
potential for the ignition of flammable fluids and vapors. 
Historically, pilots were able to see engines and identify fires or use 
the incorporated fire detection systems, or both. The ability to see 
engines provided for the rapid detection of fires, which led to fires 
being rapidly extinguished. However, engine(s) embedded in the fuselage 
or in pylons on the aft fuselage do not allow the pilot to see a fire.
    For airplanes equipped with fuselage-embedded engines, the 
consequences of a fire are more varied, adverse, and difficult to 
predict than an engine fire for a typical part 23 airplane. An engine 
embedded in the fuselage offers minimal opportunity to actually see a 
fire. Therefore, an engine's location becomes critical to the ability 
to see and extinguish an engine fire. With fuselage-embedded engines, 
an engine fire could affect both the airplane's fuselage and the 
empennage structure, which include the pitch and yaw controls. A 
sustained fire could further result in the loss of airplane control 
before a pilot could make an emergency landing.

[[Page 75744]]

    Transport Canada stated that a clarification for embedded engines 
would be useful. The FAA believes the term ``embedded'' is not 
confusing. A general definition of the term, which is to enclose 
closely in a surrounding mass, is adequate. Therefore, we do not 
provide further clarification of the term in this final rule.
    The FAA also proposed to change requirements in Sec.  23.1195 for 
fire extinguishing systems, extinguishing agent containers, and fire 
extinguishing system materials. Diamond and Cirrus stated the issue is 
location of the engine(s) rather than the airplane category or type of 
engine. The FAA agrees and modified the rule to make it applicable to 
all part 23 airplanes with fuselage-embedded engines and to any part 23 
airplanes with engines mounted in pylons on the aft fuselage. For 
embedded engine installations, a two-shot fire-extinguishing system 
would be required because the metallic components in the fire zone can 
become hot enough to reignite flammable fumes after extinguishing the 
first fire.
    GAMA, Cessna, and Cirrus objected to the requirement for a two-shot 
fire extinguishing system if an engine is embedded. Commenters had 
various reasons for their objections. However, while engines other than 
those embedded in a fuselage could reignite a fire, the hazard of fire 
damage to empennage flight controls or primary structure is greater for 
embedded engines than for other engine mounting installations. Cirrus 
also stated the rule change was not needed because small airplanes, 
including some jets, can descend and land in 15 minutes, as stated in 
the NPRM.
    We agree that some jets will likely be able to descend and land in 
15 minutes without a problem, if an adequate airport is available. 
However, altitude is only one issue. These airplanes are approved for 
Instrument Flight Rules (IFR), so the ability to continue safe flight 
and landing also must consider time to descend under Air Traffic 
Control (ATC) through Instrument Meteorological Conditions (IMC) and 
make an approach and a go-around. Also, the ability to land off airport 
is an issue for an airplane with a 65 knot or higher stall speed.

I. Avionics, Systems, and Equipment Changes

    The FAA proposed removing Sec.  23.1301(d) to improve 
standardization for systems and equipment certification, particularly 
for non-required equipment and non-essential functions embedded within 
complex avionic systems. EASA stated it will retain Sec.  23.1301(d). 
Individuals also asked the FAA to retain this paragraph for non-
required equipment and systems and intended functions.
    Section 23.1301(d) is directed towards environmental qualifications 
and operating conditions of the equipment and systems. The requirement 
in Sec.  23.1309(a) replaces the requirement in Sec.  23.1301(d) and, 
if Sec.  23.1301(d) were retained, there would be a duplication of 
requirements. The requirement for intended function is further 
explained in Sec. Sec.  23.1309(a)(1) and (a)(2) and the NPRM.
    Removal of Sec.  23.1301(d) aligns with the proposed changes to 
Sec.  25.1301(d) that was developed by the Joint Aviation Authorities 
(JAA) of Europe and the Aviation Rulemaking Advisory Committee (ARAC), 
which was established on January 22, 1991 (56 FR 2190). We have decided 
to adopt this proposal without change.
    Proposed Sec.  23.1305 would have eliminated the need for an ELOS 
finding for digital engine display parameters. It would have added 
requirements regarding usability for an ELOS finding. In addition, the 
ELOS finding would include the requirements for color indications for 
normal operation, operation in a caution range, and exceeding any 
limitation. These changes, however, were not part of the NPRM. 
Furthermore, there would still be a need for an ELOS finding for 
digital engine display parameters due to the digital indications being 
noncompliant with the requirements of Sec.  23.1549.
    The FAA received seven comments. The FAA did not adopt these 
comments since the FAA is withdrawing the proposed change to Sec.  
23.1305.
    The FAA proposed Sec.  23.1307 to require applicants to install the 
equipment necessary for anticipated operations (for example, operations 
identified in parts 91 and 135 and meteorological conditions). Cirrus, 
Embraer, and GAMA stated that the examples identified in proposed Sec.  
23.1307 add little value and could increase burden on the manufacturer. 
The FAA agrees the certification applicant does not need to comply with 
the operational requirements of parts 91 and 135 at the time of 
certification. Therefore, we are withdrawing this proposal.
    The FAA proposed changing the requirements for two different types 
of equipment and systems installed in the airplane. Section 23.1309 
lists the qualifiers ``under the airplane operating and environmental 
conditions.'' This section also describes two actions for the 
applicant. First, the applicant must consider the full normal operating 
envelope of the airplane, as defined by the Airplane Flight Manual, 
with any modification to that envelope associated with abnormal or 
emergency procedures and any anticipated crew action. Second, the 
applicant must consider the anticipated external and internal airplane 
environmental conditions, as well as any additional conditions where 
equipment and systems are assumed to ``perform as intended.''
    Section 23.1309(a)(2) requires analysis of any installed equipment 
or system with potential failure condition that are catastrophic, 
hazardous, major, or minor to determine their impact on the safe 
operation of the airplane. The applicant must show that they do not 
adversely affect proper functioning of the equipment, systems, or 
installations covered by Sec.  23.1309 and do not otherwise adversely 
influence the safety of the aircraft or its occupants.
    Section 23.1309(a)(2) does not mandate that non-required equipment 
and systems function properly during all airplane operations once in 
service, provided all potential failure conditions have no effect on 
the safe operation of the airplane. The equipment or system must 
function in the manner expected by the manufacturer's operating manual 
for the equipment or system. An applicant's statement of intended 
function must be sufficiently specific and detailed so that the FAA can 
evaluate whether the system is appropriate for the intended 
function(s).
    Garmin and Hawker Beechcraft stated, ``* * * radio frequency energy 
and the effects (both direct and indirect) of lightning strikes'' 
should be removed from Sec.  23.1309(a)(1). Their rationale is that 
there are specific requirements in Sec.  23.1308 for HIRF and for 
lightning in Sec. Sec.  23.867 and 23.954.
    The NPRM included this phrase to replace the existing general 
requirements in Sec.  23.1309(e) for the indirect effects of lightning. 
Since there is a specific HIRF requirement in Sec.  23.1308, the FAA 
agrees to remove the words ``radio frequency.'' Sections 23.867 and 
23.954 are requirements for the direct effects of lightning; therefore, 
the FAA also agrees to remove the word ``direct.''
    Several months after the FAA issued the NPRM for this rule, the FAA 
issued an NPRM (75 FR 16676, April 2, 2010) proposing specific 
requirements for the indirect effects of lightning in proposed Sec.  
23.1306. The FAA plans to keep the requirement for indirect effects of 
lightning in Sec.  23.1309(a)(1) until that final rule publishes.
    GAMA and Garmin suggested deleting the phrase ``or systems whose 
improper function could reduce safety'' in

[[Page 75745]]

Sec.  23.1309(a)(1). However, they agree to the explanation of the 
requirements in the preamble of the NPRM. They also stated the rule 
would be challenging to comply with since proposed Sec.  23.1309(b) 
deals with failure conditions such as the effects of malfunctions. The 
FAA agrees and has removed the phrase.
    Several commenters stated that Sec.  23.1309(a)(2) should be 
revised by replacing the beginning phrase ``Those required for type 
certification or by operating rules and other'' with ``Any.'' This 
revision is not a substantive change, and the FAA has revised the 
phrase as requested.
    Cessna and Garmin stated that the safety assessment process in 
proposed Sec.  23.1309(b) should not supersede the HIRF requirements of 
Sec.  23.1308 and proposed Sec.  23.1306, electrical and electronic 
system lightning protection. They also stated that the environmental 
effects, such as HIRF and lightning, should not be considered in 
combination with another single failure or pre-existing latent failure. 
The FAA agrees.
    We proposed that Sec.  23.1309(a)(3) be applicable for all 
functional reliability, flight testing, or flight evaluations. Proposed 
Sec.  23.1309(a)(3) was revised to be applicable during Type Inspection 
Authorization (TIA) and FAA flight-certification testing.
    Proposed Sec.  23.1309(a)(3) is being changed to Sec.  23.1309(b) 
in this final rule. Cessna, Embraer, and Garmin stated that the 
probability requirements were not appropriate for typical certification 
flight test, but portions of the preamble material are appropriate for 
advisory material. They also commented that root cause analysis and 
corrective action is the current industry practice and should be 
reflected in the rule. The FAA does not intend for the probability 
requirements, based on random distribution across a fleet of aircraft, 
to be applied on the beginning phase of operation. The FAA accepted 
these comments and modified proposed Sec.  23.1309(b) in this final 
rule. This section was revised to be applicable during TIA and FAA 
flight-certification testing. This requirement now reads: ``Minor, 
major, hazardous, or catastrophic failure condition(s), which occur 
during TIA or FAA flight-certification testing, must have root cause 
analysis and corrective action.''
    The FAA expects the applicant to show the system does not exhibit 
unintended or undesirable failure conditions that are minor, major, 
hazardous, or catastrophic. Guidance will be provided in AC 23.1309-1E.
    Garmin stated that the FAA removed the catastrophic failure 
condition limitation for the Visual Flight Rules (VFR) airplane from 
proposed Sec.  23.1309(b) without explanation. We removed this 
limitation since airplanes limited to VFR operation may have 
technologies that were not envisioned when Amendment 23-41 was 
developed. The advanced complex technologies now being installed also 
need to undergo the system safety assessment process.
    Several proposed amendments to introductory text for Sec.  23.1309 
and Appendix K would have codified a long-established means of 
compliance with current equipment, systems, and installations 
requirements. We also proposed updating failure condition(s) 
terminology used in related system safety assessment documents 
developed by industry working groups (e.g., RTCA and the Society of 
Automotive Engineers (SAE)). Some of this material identifies four 
classes of airplanes, as defined in Appendix K, and applies appropriate 
probability values and development assurance levels for each class. The 
FAA added this material as proposed requirements in the NPRM due to 
problems with one significant certification program.
    EASA stated that the proposed requirements and current requirements 
are applicable and no hierarchy is implied. EASA also stated that both 
specific and general requirements should apply, and the exceptions to 
other requirements should be listed. Time and the often case-by-case 
nature of exceptions do not permit the FAA to list all (potential) 
exceptions for Sec.  23.1309. The FAA has withdrawn the proposed 
exceptions from Sec.  23.1309 but will list some of them in AC 23.1309-
1E. The FAA will determine and consider additional exceptions in future 
revisions of AC 23.1309. Until then, applicants and certification 
authorities should contact the FAA, Small Airplane Directorate for 
approval of additional exceptions.
    Boeing, Cessna, Cirrus, Diamond, Embraer, GAMA, Garmin, GE, and 
Hawker Beechcraft stated that the guidance and clarification to 
proposed sections and Appendix K should not be regulatory text and 
should only be in the guidance material of AC 23.1309-1E. They stated 
that most of these proposed changes would result in more confusion and 
less standardization. They also asserted that there would be more 
exemptions, ELOS findings, and complicated compliance demonstrations 
with no safety benefit. As such, this would cause additional burden, 
inefficiencies, and cost. The commenters further asserted that having 
this material available only as guidance would allow the applicant to 
choose an alternative to the proposed requirements as a means of 
compliance.
    The FAA acknowledges that there has not been a problem with most 
applicants using this material as a means of compliance when only using 
AC 23.1309-1D, except for one type-certification program. Therefore, 
the FAA has decided not to proceed with the pertinent proposed 
amendments to Sec.  23.1309(b)(4), (b)(5), (c), (d), and (e) and will 
also not codify Appendix K. As requested, this material will remain 
available as a means of compliance in AC 23.1309-1E. Proposed 
Sec. Sec.  23.1309 (b)(1), (b)(2), and (b)(3) are now redesignated as 
Sec. Sec.  23.1309(c)(1), (c)(2), and (c)(3) since proposed Sec.  
23.1309(a)(3) is redesignated as Sec.  23.1309(b) in this final rule, 
as discussed above.
    Cirrus stated that note 5 in figure 2 of AC 23.1309-1C/D, should 
also be in Appendix K. Neither Appendix K nor figure 2 of AC 23.1309-1E 
contained note 5 as AC 23.1309-1C/D did. Note 5 allows an additional 
reduction of Development Assurance Level (DAL) for Navigation, 
Communication, and Surveillance Systems if an altitude encoding 
altimeter transponder is installed and it provides the appropriate 
mitigations.
    This note was deleted since it was misused, and it is not 
appropriate to use a transponder as mitigation. If the transponder is 
actually providing mitigations for failure conditions, then the note is 
unnecessary for the system assessment process. Note 5 is removed from 
AC 23.1309-1E and, as stated above, the proposal to codify Appendix K 
is withdrawn.
    GE stated that the implementation of the four classes of airplanes, 
in Appendix K of the NPRM, has a sliding scale of acceptable risk/
severity. That scale depends on airplane category, and it introduces 
inconsistency with other rules. GE believes this may lead to confusion 
of different numeric interpretations depending on the size of the 
airplane.
    The FAA developed the four classes of airplanes in AC 23.1309-1C 
over 10 years ago for the implementation of modern avionics that 
provide safety benefits in part 23 airplanes. History has shown that 
developing the four classes improves safety, without confusion, due to 
the new features on electronic systems being installed. The aviation 
industry as a whole is on the threshold of a revolutionary change in 
communication, navigation, and surveillance of aircraft operations. The 
four-class certification criteria have

[[Page 75746]]

been shown to be beneficial for new technologies and affordable for 
General Aviation. The FAA considers the four-classes more appropriate 
for an advisory circular and has decided to retain the four classes of 
airplanes in AC 23.1309-1E and to remove Appendix K.
    The FAA proposed revising Sec.  23.1309(f) to make it compatible 
with the current Sec.  23.1322 (``Warning, caution, and advisory 
lights''), which distinguishes between caution, warning, and advisory 
lights installed on the flight deck. Other paragraphs were deleted from 
this section, as mentioned earlier; therefore, Sec.  23.1309(f) has 
been redesignated as Sec.  23.1309(d). Rather than only providing a 
warning to the flight crew, which is required by the current rule, 
newly redesignated Sec.  23.1309(d) requires that information 
concerning an unsafe system operating condition(s) be provided to the 
flight crew.
    Section 23.1309(d) also specifies that the design of systems and 
controls, including indications and annunciations, must reduce crew 
errors that could create more hazards. The additional hazards to be 
minimized include those caused by inappropriate actions by a crewmember 
in response to the failure, or those that could occur after a failure.
    The FAA proposed a new Sec.  23.1310 that was previously part of 
Sec.  23.1309. The proposed change would not have changed the current 
requirements; the only change would have been the new section 
designation.
    In the past, Sec.  23.1309 and Sec.  25.1309 had the same power 
source requirements. Then, there was a proposal for part 25 to move 
these requirements from Sec.  25.1309 to Sec.  25.1310 without change. 
In Amendment 25-123 (72 FR 63405, November 8, 2007), the proposed 
requirements were changed for clarification without substantial changes 
to the requirements.
    GAMA suggested a revision for clarification. Therefore, the FAA 
made a change to Sec.  23.1310 in the final rule by adopting the 
requirements in Sec.  25.1310. This will also provide consistency in 
our standards.
    The FAA also proposed amendments for plain language purposes. 
Transport Canada stated the word ``instrument,'' which appears in 
several section titles in part 23, should be replaced with 
``indications.'' The FAA disagrees and maintains that the use of the 
word ``instrument'' is clear and appropriate.
    GAMA stated the requirements in Sec.  23.1311(a)(5) should only be 
applicable when part 23 airplanes are operating in IFR conditions. GAMA 
also noted that some of the equipment listed, like attitude, is not 
required for Visual Flight Rules (VFR). The FAA agrees attitude 
instruments are not required for VFR operations under part 91.
    The redundancy requirements for some flight instruments or 
indicators may be too restrictive for airplanes limited to VFR 
operations only. This has caused several applicants to request an ELOS 
from Sec.  23.1311(a)(5) for installation approval of electronic 
displays in part 23 airplanes limited to VFR operations only. The FAA 
agrees with this comment since it would reduce the burden of processing 
multiple ELOS findings.
    We proposed clarifying the requirements for ``sensory cues'' in 
Sec.  23.1311(a)(6). We also proposed amending Sec.  23.1311(a)(7) to 
make acceptable instrument markings on electronic displays equivalent 
to those instrument markings on conventional mechanical and 
electromechanical instruments. Several commenters suggested minor 
changes to the requirements for clarification. The FAA agrees with most 
of these changes and has made them in this final rule.
    The FAA proposed amending Sec.  23.1311(b) by replacing the phrase 
``remain available to the crew, without need for immediate action'' 
with ``be available within one second to the crew by a single pilot 
action or by automatic means.'' This proposal would allow an applicant 
to take credit for reversionary or secondary flight displays on multi-
function flight displays that provide a secondary means of primary 
flight information.
    Embraer stated the one-second requirement in Sec.  23.1311(b) 
should be limited to the display of attitude. The FAA disagrees but 
acknowledges that in most current certifications of part 23 airplanes, 
the attitude is the only information considered essential for continued 
safe flight and landing. The FAA does not want to limit the one-second 
requirement to only attitude. With the expansion of future advanced 
technologies, some airplanes may have other information essential for 
continued safe flight and landing.
    GAMA, Cessna, and Garmin commented on making minor changes to 
proposed Sec.  23.1311 for clarification. We incorporated most of these 
changes. Garmin suggested other minor recommendations to the NPRM. We 
also accepted most of these recommendations. They will be reflected in 
AC 23.1311-1C.
    To meet the jet performance requirements in Subpart B, the pilot 
needs accurate speed indicators while accelerating on the runway. We 
proposed revisions to add the requirement to calibrate the airspeed 
system down to 0.8 of the minimum value of V1. We also 
proposed the language used in part 25 for this same requirement because 
it is more in line with operating new part 23 jets.
    Diamond asked why this requirement is specific to jets and commuter 
category aircraft. Additionally, Diamond found the wording used in 
proposed Sec.  23.1323(e) confusing and suggested that it be reworded. 
If the intent is to keep this rule applicable to multiengine and 
commuter jets, then the commenter recommends removing the words normal, 
utility, and acrobatic (which represent the different categories of 
aircraft).
    The requirement in the prior amendment for Sec.  23.1323(e) was 
applicable to the commuter category because only those part 23 
airplanes were required to be certificated for accelerate-stop testing. 
The proposed amendment changed Sec.  23.55 to require accelerate-stop 
testing for multiengine jets weighing more than 6,000 pounds, as well 
as commuter category airplanes. A multiengine airplane can be commuter 
category, but it may also be in the normal, utility, or the acrobatic 
category. This final rule will clarify that all multiengine jets 
weighing more than 6,000 pounds are subject to accelerate-stop testing, 
regardless of category or whether it is a turboprop or jet. This final 
rule also adds the requirement to calibrate the airspeed system down to 
0.8 of the minimum value of V1.
    Changes to pitot heat indication systems requirements in Sec.  
23.1326 were not included in the NPRM. Cessna stated that the previous 
rule required an amber light during startup and taxi when there was no 
safety issue. Since current annunciation systems provide the ability to 
change the annunciation of pitot heat during flight phases to amber, 
the rule should acknowledge the capability. Cessna suggested that the 
rule specify the following: ``If a flight instrument pitot heating 
system is installed to meet the requirements specified in Sec.  
23.1323(d), an indication system must be provided to indicate to the 
flight crew when that pitot heating system is not operating during 
takeoff or in flight.''
    The FAA agrees, but the amber light must be operating except when 
the airplane is on the ground. However, since this comment is beyond 
the scope of the current rulemaking, the FAA did not include this 
change in the final rule.
    The FAA further proposed to change requirements for instruments 
that use a power source. Proposed Sec.  23.1331 would apply to 
instruments that rely on

[[Page 75747]]

a power source to provide required flight information for IFR 
operations. Independent power sources must be provided for these 
instruments or a separate display of the parameters that have a power 
source independent from the airplane's primary electrical power system. 
Embraer requested clarification of Sec.  23.1331(c)(2) without 
substantial change to the requirements. The FAA agrees and made those 
changes in this final rule.
    Cirrus stated that an additional heading display should not be 
required in Sec.  23.1331(c)(2) for small general aviation aircraft 
since heading has a low safety criticality relative to altitude, 
attitude, and airspeed for this class of airplane. The FAA disagrees 
since an additional or separate display is not required if there are 
two independent power sources. Heading is an important parameter, and 
Sec.  91.205 requires a stabilized heading source for IFR operations, 
in addition to the magnetic direction indicator.
    Proposed amendments for storage battery design and installation in 
Sec.  23.1353 would have added additional battery endurance 
requirements to enhance safety based on the airplane's altitude 
performance. The proposal addressed the power needs of new all-
electrical instruments, navigation and communications equipment, and 
engine controls.
    When those requirements were initially adopted, part 23 airplanes 
were mostly mechanical. All-electric, or almost all-electric airplanes 
were not envisioned. Previously, the FAA required 30 minutes of 
sufficient electrical power for a reduced or emergency group of 
equipment and instrumentation. The FAA considered 30 minutes adequate 
to reach VFR conditions to continue flying to an adequate airport and 
to accomplish a safe landing for traditional part 23 airplanes.
    Integrated electrical cockpits were also not envisioned during 
initial development of those requirements. Currently, new part 23 
airplanes are being certificated with all-electrical instruments, 
including the standby instruments. This reliance on electric power has 
increased the importance of ensuring adequate battery power until the 
pilot can descend and make a safe landing.
    Most new turbine-powered airplanes, and some turbocharged, piston-
powered airplanes, operate at high altitudes under IFR. Under these 
conditions, 30 minutes may not be adequate for battery power because it 
would take more time to descend from maximum altitude to find visual 
meteorological conditions (VMC) and land, or to perform an instrument 
approach for a landing. For these reasons, the proposed requirement 
would extend the battery time requirement to 60 minutes for approved 
airplanes with a maximum operating altitude above 25,000 feet. The 30 
minute battery capacity was retained for airplanes with a maximum 
operating altitude of 25,000 feet or less.
    We received five comments on this issue. Cessna, Diamond, and GAMA 
stated that the 60-minute battery capacity should not be required. They 
suggested a requirement to demonstrate descent and landing plus 10 
minutes. Cirrus recommended a second energy source instead of a 60-
minute battery. EASA suggested including the time to recognize the 
failure and take load shedding action, which was inadvertently omitted 
in the NPRM.
    The FAA disagrees with the Cessna, Diamond, and GAMA's comments. 
While jets often have speed brakes and a high dive speed, the rule 
requires descent and landing. Jets also typically have high stall 
speeds, which may limit the number of airports where they can safely 
land, and off-airport landing capability is minimal. There are also 
piston-powered airplanes that operate above 25,000 feet with 
turbocharging, which do not have the dive speed and speed brakes often 
installed in jets. All of these airplanes can operate in IMC, which can 
delay the landing. Thus, the 60-minute battery capacity is valid for 
higher performance aircraft that operate above 25,000 feet.
    The FAA also disagrees with Cirrus that a separate power source is 
superior to a 60-minute battery. Single- or dual-power sources are not 
causes for concern because the intent of Sec.  23.1353(h) is to assume 
the loss of all generated power.
    There was not a proposal in the NPRM to revise Sec.  23.1431, 
electronic equipment, but editorial changes have become necessary since 
there were paragraph designation changes in Sec.  23.1309.
    We proposed changing requirements in Sec.  23.1443 for minimum mass 
flow of supplemental oxygen. The FAA has addressed oxygen systems for 
airplanes operating above 41,000 feet using special conditions derived 
from part 25. A large number of new jets and high-performance airplanes 
applying for part 23 certification operate at higher altitudes than 
previously envisioned for part 23 airplanes. Proposed revisions would 
establish requirements for those oxygen systems. These proposed 
revisions would also eliminate the need for oxygen system special 
conditions for airplanes with maximum operating altitudes above 41,000 
feet.
    Cessna and EASA stated that the proposed rule conflicted with 
another rule for crew oxygen equipment since a continuous oxygen system 
is unacceptable for the crew at that altitude. The FAA agrees and has 
modified Sec.  23.1443(a) to apply continuous flow oxygen systems only 
to passengers for operations above 41,000 feet as required by Sec.  
23.1441(d).

J. Placards, Operating Limitations, and Information

    Proposed revisions to airspeed limitations in Sec.  23.1505(c) 
would include jet-specific V-speeds. This proposal would base airspeed 
limits on a combination of analytical (VD/MD) and 
demonstrated (VDF/MDF) dive speeds for jets.
    The FAA received one comment from EASA. EASA stated that it applies 
a special condition for high-speed characteristics not included in our 
proposal. Again, EASA's comment suggests performance-based standards. 
Amending part 23 to a performance-based standard is a substantially 
larger initiative than this rulemaking effort.
    The FAA also proposed amendments that were clarifying in nature so 
applicants would understand that they may need additional equipment for 
their airplane(s) to conduct part 135 operations. Part 23 is a minimum-
performance standard, and it may not include all the required equipment 
for operations under part 135. Proposed revisions to Sec.  23.1525 
would include parts 91 and 135 as potential kinds of authorized 
operation.
    The FAA received comments from Transport Canada, Embraer, Cirrus, 
and Diamond. All four commenters stated that the operating rules should 
not be referenced in part 23. There was concern the proposed revisions 
could be misinterpreted and increase the certification burden to 
manufacturers. We do not intend to add any burden to manufacturers. We 
simply wanted to remind them that in many cases, part 135 operations 
require additional equipment not typically installed as standard 
equipment in part 23 airplanes. However, in light of those comments, 
this proposal is withdrawn.
    The FAA proposed revising Sec. Sec.  23.1583(c)(3), 23.1583(c)(4), 
and 23.1583(c)(5), operating limitations; Sec.  23.1585(f), operating 
procedures; and Sec.  23.1587(d) performance information by applying 
most commuter category performance requirements to jets weighing over 
6,000 pounds. The proposed AFM requirements would maintain consistency 
with the

[[Page 75748]]

performance requirements proposed in Subpart B. These requirements 
include the single-engine climb performance increase for turboprops.
    The FAA received three comments, one from EASA, Diamond, and 
Transport Canada. EASA states that it requires a special condition for 
landing distance factors not included in our proposal. This comment is 
outside the scope of this rulemaking effort. Diamond questioned the 
distinction between turbines and high-performance piston airplanes. The 
FAA agrees conceptually with these comments, but they are also beyond 
the scope of this rulemaking effort. Transport Canada stated that part 
23 jets should include data for wet and contaminated runways. The 
upcoming part 23 regulatory review for future rulemaking will consider 
performance data.

K. Test Procedure and Appendices

    The FAA proposed changing Appendix F, which is the test procedure 
for the requirement in Sec.  23.856. GE asked if the test procedure was 
new. The test procedure is not new; Appendix F modifications made new 
part 23, Appendix F, part II, identical to part 25, Appendix F, part 
VI. GAMA questioned the use of a brand name in the discussion of 
Appendix F, Figure F1. In response, we reaffirm the use of the brand 
name as adopted from part 25, Appendix F. Again, our efforts toward 
standardization should be maintained wherever appropriate in our 
requirements. Appendix F is adopted as proposed.

III. Regulatory Analyses

Paperwork Reduction Act

    The Paperwork Reduction Act of 1995 (44 U.S.C. 3507(d)) requires 
that the FAA consider the impact of paperwork and other information 
collection burdens imposed on the public. The FAA has determined that 
there is no new requirement for information collection associated with 
this final rule.

International Compatibility

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation, it is FAA policy to conform to 
International Civil Aviation Organization (ICAO) Standards and 
Recommended Practices to the maximum extent practicable. The FAA has 
reviewed the corresponding ICAO Standards and Recommended Practices and 
has identified no differences with these regulations.

Regulatory Evaluation, Regulatory Flexibility Determination, 
International Trade Impact Assessment, and Unfunded Mandates Assessment

    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Order 12866 directs that each Federal agency 
shall propose or adopt a regulation only upon a reasoned determination 
that the benefits of the intended regulation justify its costs. Second, 
the Regulatory Flexibility Act of 1980 (Pub. L. 96-354) requires 
agencies to analyze the economic impact of regulatory changes on small 
entities. Third, the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires agencies to prepare a written assessment of the costs, 
benefits, and other effects of proposed or final rules that include a 
Federal mandate likely to result in the expenditure by State, local, or 
Tribal governments, in the aggregate, or by the private sector, of $100 
million or more annually (adjusted for inflation with base year of 
1995). This portion of the preamble summarizes the FAA's analysis of 
the economic impacts of this final rule. Readers seeking greater detail 
should read the full regulatory evaluation, a copy of which we have 
placed in the docket for this rulemaking.
    In conducting these analyses, the FAA has determined that this 
final rule: (1) Has benefits that justify its costs, (2) is not an 
economically ``significant regulatory action'' as defined in section 
3(f) of Executive Order 12866, (3) is ``significant'' as defined in 
DOT's Regulatory Policies and Procedures; (4) will not have a 
significant economic impact on a substantial number of small entities; 
(5) will not create unnecessary obstacles to the foreign commerce of 
the United States; and (6) will not impose an unfunded mandate on 
state, local, or Tribal governments, or on the private sector by 
exceeding the threshold identified above. These analyses are summarized 
below.
Total Benefits and Costs of This Rule
    The estimated cost of this final rule ranges from a low of $65.2 
million to a high of $72.9 million in nominal dollars ($22.9 million to 
$26.7 million at a seven percent present value).
    The total benefits are equal to the sum of the safety and 
efficiency benefits. The estimated safety benefits of avoiding 26 
accidents on newly certificated part 23 airplanes over the 57-year 
analysis interval are estimated at about $187.1 million in nominal 
dollars ($46.5 million at a seven percent present value).
    The estimated efficiency benefits to streamline the part 23 
certification process are valued at about $965 thousand, in nominal 
dollars, for five special conditions per aircraft certification, to 
about $1.5 million, in nominal dollars, for eight special conditions 
per aircraft certification. The total benefits range from a low of 
about $188.1 million to high of about $188.6 million in nominal 
dollars. The following table shows these results.
[GRAPHIC] [TIFF OMITTED] TR02DE11.078

Who is Potentially Affected by This Rule
    This rulemaking will affect U.S. manufacturers and operators of 
part 23 turbojets, turboprops, and reciprocating engine airplanes.
Assumptions
    This final rule makes the following assumptions:
     The base year is 2010;

[[Page 75749]]

     The average life of a U.S.-operated part 23 airplane is 32 
years;
     The average part 23 airplane production life cycle is 25 
years;
     The analysis period extends for 57 years (32 + 25); and
     The value of a fatality avoided is $6.0 million.
Benefits of This Rule
    The FAA estimates the final rule will avoid 26 accidents over the 
32-year operating life of 29,725 newly certificated and delivered part 
23 airplanes. The resulting benefits include standardizing and 
streamlining the certification process, averted fatalities and 
injuries, loss of airplanes, investigation cost, and collateral damages 
for the accidents.
    The safety benefits for averting the 26 accidents are about $187.1 
million in nominal dollars ($46.5 million at a seven percent present 
value). Other benefits of this final rule include FAA and industry 
paperwork and certification time saved by standardizing and 
streamlining the certification of part 23 airplanes. These efficiency 
benefits for standardizing and streamlining the certification process 
range from a low estimate of about $965 thousand to a high estimate of 
$1.5 million in nominal dollars.
    The total benefits are equal to the sum of the safety and 
efficiency benefits and range from a low of about $188.1 million to 
high of about $188.6 million in nominal dollars.
Costs of This Rule
    Estimated nominal dollar unit costs per part 23 airplane could be 
as high as: $1,009 for reciprocating engine airplanes, $6,105 for 
turboprops, and $8,053 for turbojets. Total incremental costs equal the 
nominal dollar unit costs multiplied by the number of newly 
certificated airplanes produced and delivered over the analysis 
interval. The estimated cost of this final rule ranges from a low of 
$65.2 million to high of $72.9 million in nominal dollars ($22.9 
million to $26.7 at a seven percent present value).
Alternatives Considered
     Alternative 1--The FAA would continue to issue special 
exemptions, exceptions and equivalent levels of safety to certificate 
part 23 airplanes. As that would perpetuate ``rulemaking by 
exemption,'' we choose not to continue with the status quo; and
     Alternative 2--The FAA would continue to enforce the 
current regulations that affect single-engine climb performance and 
power loss. The FAA rejected this alternative because the accident rate 
for part 23 airplanes identified a safety issue that had to be 
addressed.

Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA) 
establishes ``as a principle of regulatory issuance that agencies shall 
endeavor, consistent with the objectives of the rule and of applicable 
statutes, to fit regulatory and informational requirements to the scale 
of the businesses, organizations, and governmental jurisdictions 
subject to regulation. To achieve this principle, agencies are required 
to solicit and consider flexible regulatory proposals and to explain 
the rationale for their actions to assure that such proposals are given 
serious consideration.'' The RFA covers a wide range of small entities, 
including small businesses, not-for-profit organizations, and small 
governmental jurisdictions.
    Agencies must perform a review to determine whether a rule will 
have a significant economic impact on a substantial number of small 
entities. If the agency determines that it will, the agency must 
prepare a regulatory flexibility analysis as described in the RFA.
    However, if an agency determines that a rule is not expected to 
have a significant economic impact on a substantial number of small 
entities, Section 605(b) of the RFA provides that the head of the 
agency may so certify and a regulatory flexibility analysis is not 
required. The certification must include a statement providing the 
factual basis for this determination, and the reasoning should be 
clear.
    The FAA has determined that this final rule will not have a 
significant impact on a substantial number of small entities. The 
purpose of this analysis is to provide the reasoning underlying the 
FAA's determination.
    The FAA made the same determination that this proposal would not 
have a significant impact on a substantial number of small entities in 
the notice of proposed rulemaking (NPRM). The only comment regarding 
small entities for the NPRM was Sino Swearingen, who requested we note 
that it is now Emivest Aerospace, which is foreign owned.
    First, we will discuss the reasons why the FAA is considering this 
action. We will follow with a discussion of the objective of, and legal 
basis for, the rule. Next we explain there are no relevant federal 
rules which may overlap, duplicate, or conflict with the final rule. 
Lastly, we will describe and provide an estimate of the number of small 
entities affected by the final rule and why the FAA believes this final 
rule will not result in a significant economic impact on a substantial 
number of small entities.
    We now discuss the reasons why the FAA is considering this action.
    The FAA proposed this action to amend safety and applicability 
standards for part 23 turbojets to reflect the current needs of the 
industry, accommodate future trends, address emerging technologies, and 
provide for future aircraft operations. This final rule primarily 
standardizes and streamlines the certification of part 23 turbojets. 
The changes to part 23 are necessary to eliminate the current workload 
of exemptions, special conditions, and equivalent levels of safety 
necessary to certificate part 23 turbojets. These part 23 changes will 
also clarify areas of frequent non-standardization and 
misinterpretation and provide appropriate safety and applicability 
standards that reflect the current state of the industry, emerging 
technologies and new types of operations for all part 23 airplanes, 
including turbojets, turboprops, and reciprocating engine airplanes.
    The FAA currently issues type certificates (TCs) for part 23 
turbojets using extensive special conditions. Issuance of TCs has not 
been significant until now because there were few part 23 turbojet 
certification programs. However, in the past seven years, the number of 
new part 23 turbojet certification programs has increased by more than 
100 percent when compared to over the past three decades.
    The need to incorporate these special conditions into part 23 stems 
from both the existing number of new turbojet certification programs 
and the expected number of future turbojet programs. Codifying these 
special conditions will allow manufacturers to know the requirements 
during the design phase instead of designing the turbojet and then 
having to apply for special conditions that may ultimately require a 
redesign. Codifying will also reduce the manufacturers and FAA's paper 
process required to type certificate an airplane and reduces the 
potential for program delays. These final rule changes will also 
clarify areas of frequent non-standardization and misinterpretation, 
particularly for electronic equipment and system certification on all 
newly certificated part 23 airplanes.
    The revisions include general definitions, error corrections, and 
specific requirements for performance and handling characteristics to 
ensure safe operation of part 23 airplanes. The revisions will apply to 
all future new part 23 turbojets, turboprops, and

[[Page 75750]]

reciprocating engine airplane certifications.
    We now discuss the legal basis for, and objective of, the rule. 
Next, we discuss if there are relevant federal rules that may overlap, 
duplicate, or conflict with the rule.
    The FAA's authority to issue rules on aviation safety is found in 
Title 49 of the United States Code. Subtitle I, Section 106 describes 
the authority of the FAA Administrator. Subtitle VII, Aviation 
Programs, describes in more detail the scope of the agency's authority.
    This rulemaking is promulgated under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701. Under that section, 
the FAA is charged with promoting safe flight of civil aircraft in air 
commerce by prescribing minimum standards required in the interest of 
safety for the design and performance of aircraft. This regulation is 
within the scope of that authority because it prescribes new safety 
standards for the design of part 23 normal, utility, acrobatic, and 
commuter category airplanes.
    Accordingly, this final rule will amend Title 14, the Code of 
Federal Regulations to address deficiencies in current regulations 
regarding the certification of part 23 light turbojets, turboprops and 
reciprocating engine airplanes. The final rule will also clarify areas 
of frequent non-standardization and misinterpretation and codify 
certification requirements that currently exist in special conditions.
    The rule will not overlap, duplicate, or conflict with existing 
federal rules.
    We now discuss our methodology to determine the number of small 
entities for which the rule will apply.
    Under the RFA, the FAA must determine whether a proposed or final 
rule significantly affects a substantial number of small entities. This 
determination is typically based on small entity size and cost 
thresholds that vary depending on the affected industry.
    Using the size standards from the Small Business Administration for 
Air Transportation and Aircraft Manufacturing, we defined companies as 
small entities if they have fewer than 1,500 employees.\2\
---------------------------------------------------------------------------

    \2\ 13 CFR 121.201, Size Standards Used to Define Small Business 
Concerns, Sector 48-49 Transportation, Subsector 481 Air 
Transportation.
---------------------------------------------------------------------------

    There are nine U.S.-owned aircraft manufacturers who deliver part 
23 airplanes in the 1998-2009 analysis interval. These manufacturers 
are American Champion, Cessna, Cirrus, Hawker Beechcraft, Liberty, 
Maule, Mooney, Piper, and Quest.
    Using information provided by the World Aviation Directory, 
Internet filings and industry contacts, manufacturers that are 
subsidiary businesses of larger businesses, manufacturers that are 
foreign owned, and businesses with more than 1,500 employees were 
eliminated from the list of small entities. Cessna and Hawker 
Beechcraft are businesses with more than 1,500 employees and Cirrus and 
Liberty are foreign owned. We found no source of employment or revenue 
data for American Champion. For the remaining businesses, we obtained 
company revenue and employment from the above sources.
    The base year for the final rule is 2010. Although the FAA 
forecasts traffic and air carrier fleets, we cannot determine the 
number of new entrants, nor who will be in the part 23 aircraft 
manufacturing business in the future. Therefore we use current U.S. 
part 23 aircraft manufacturers' revenue and employment in order to 
determine the number of operators this final rule will affect.
    The methodology discussed above resulted in the following list of 
four U.S. part 23 aircraft manufactures, with less than 1,500 
employees.
[GRAPHIC] [TIFF OMITTED] TR02DE11.079

    From the list of small entity U.S. airplane manufacturers above, 
there are no manufacturers currently producing part 23 turbojets; only 
Piper and Quest produce turboprops. The remaining small entity U.S. 
aircraft manufacturers produce part 23 reciprocating engine airplanes.
    The U.S. Census Bureau data on the Small Business Administration's 
Web site shows an estimate of the total number of small entities who 
could be affected if they purchase newly certificated part 23 
airplanes. The U.S. Census Bureau data lists 39,754 small entities in 
the Non-scheduled Air Transportation Industry that employ less than 500 
employees. Many of these non-scheduled businesses are subject to part 
25. Other small businesses may own aircraft and not be included in the 
U.S. Census Bureau Non-scheduled Air Transportation Industry 
category.\3\ Therefore, we will use the list of small entities from 
Table RF1 instead of the U.S. Census Bureau data for our Final 
Regulatory Flexibility Act (FRFA) analysis.
---------------------------------------------------------------------------

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

    We will now develop the estimate of the effect of this final rule 
on the total number of small entities that manufacture part 23 
airplanes.
    First, we discuss our methodology to estimate the costs of the 
final rule to the small entity part 23 airplane manufacturers and 
operators. Next, we will discuss why the FAA believes the final rule 
will not result in a significant economic impact to part 23 airplane 
manufacturers and operators.
    In 2003, we published a notice (68 FR 5488) creating the part 125/
135 Aviation Rulemaking Committee (ARC). The FAA and the part 23 
industry have worked together to develop common part 23 airplane 
certification requirements for this rulemaking. We contacted the part 
23 aircraft manufacturers, the ARC, and GAMA (an industry association 
for part 23 aircraft manufacturers) for specific cost estimates for 
each section change for the final rule. Not every party we contacted 
responded to our request for costs. Many of the ARC members, from the 
domestic and international manufacturing community, collaborated and 
filed a joint cost estimate for the proposed rule.
    We are basing our cost estimates for this final rule from data 
provided by the domestic part 23 U.S. aircraft manufacturers, ARC 
members, and GAMA. They informed us that the final

[[Page 75751]]

rule will add costs for fire extinguishing systems, climb, take-off 
warning systems, ventilation systems, system designs, and batteries. 
Industry informed us that this proposal will save the manufacturers 
design time for the certification of cockpit controls. Industry has 
also informed us that every other section of this final rule is either 
clarifying, error correcting, or will only add minimal to no costs.
    The final rule adds certification requirements for the following 
part 23 airplane categories:
    1. Turbojets;
    2. Turbojets with a MTOW less than 6,000 pounds;
    3. Turboprops;
    4. Turboprops with a MTOW less than 6,000 pounds;
    5. Reciprocating engine airplanes; and
    6. Reciprocating engine airplanes with a MTOW greater than 6,000 
pounds.
    In some cases the final rule will only affect part 23 airplanes 
operated in revenue service. Any part 23 airplane could be used as a 
business airplane to haul passengers and cargo in commercial service. 
We estimated the business versus the personal use of a part 23 airplane 
by analyzing the number of all U.S.-operated airplanes from Table 3.1 
of the 2008 General Aviation and Part 135 Activity Survey.
    Table 3.1 of that survey shows the breakout of the 2008 General 
Aviation fleet by business, corporate, instructional, aerial 
applications, aerial observations, aerial other, external load, other 
work, sight see, air medical, other, part 135 Air Taxi, Air Tours, and 
Air Medical airplane usage. For the purpose of estimating the cost of 
this proposal, we assume all-business part 23 airplane operators from 
Table 3.1 of the 2008 General Aviation and Part 135 Activity Survey 
will operate in commuter service.
    Table RF2 shows these results:
    [GRAPHIC] [TIFF OMITTED] TR02DE11.080
    
    Table RF3 shows the final rule sections that add (or subtract) 
incremental costs by increasing design or flight testing times, adding 
weight, adding batteries, or reducing payload:
[GRAPHIC] [TIFF OMITTED] TR02DE11.081

    We estimated part 23 airplane fixed manufacturer (added 
certification plus flight test hours) and operator-variable flight 
operation (added weight, batteries, or a reduction in payload) costs 
and applied our estimated costs to the expected fleet delivered in 
compliance with this final rule. The total cost of this final rule is 
the sum of the fixed certification cost plus the variable flight 
operation cost multiplied by the expected newly certificated part 23 
fleet delivered over the analysis interval.
    The total fixed certification compliance cost equals the industry-
provided incremental hours or dollar costs multiplied by the expected 
number of new certifications for part 23 turbojets, turboprops, and 
reciprocating engine airplanes.
    The total variable flight operation compliance cost equals the 
industry-provided incremental weight, payload reduction, or dollar 
costs multiplied by the expected number of newly certificated part 23 
turbojets, turboprops, and reciprocating engine airplanes delivered. In 
the regulatory analysis, we estimated a low case and a high case cost 
range for the fixed operation compliance costs. The range was based on 
the 10% loss in payload capacity noted in Table RF3.
    In the low case, we estimated no loss in capacity because our 
analysis showed that part 23 airplanes operate well below the 
airplane's payload capacity. In the high case, we estimated a cost to 
operators for the 10% loss in payload capacity. We will use the high-
variable, flight operation cost scenario for this FRFA analysis.
    We estimated the nominal dollar unit costs for all part 23 
airplanes by summing the fixed certification costs

[[Page 75752]]

with the variable flight operations compliance costs by part 23 
turbojets, turboprops, and reciprocating engine airplanes. Next, we 
divided these sums by the number of newly certificated delivered part 
23 turbojets, turboprops, and reciprocating engine airplanes. Our 
calculations yielded that unit costs could be as high as $1,009 for 
newly certificated reciprocating engine airplanes and $6,105 for 
turboprop airplanes.
    We then took the product of the estimated unit airplane cost with 
the average annual number of part 23 turbojets, turboprops, and 
reciprocating engine airplanes that each of the four small business 
part 23 manufacturers (from Table RF1) delivered from 1998 to 2009. 
This product determined the annual impact of the final rule to each 
small business part 23 manufacturer. Lastly, we divided each small part 
23 airplane manufacturer's annual revenue by the incremental costs.
    Table RF4 shows these results:
    [GRAPHIC] [TIFF OMITTED] TR02DE11.082
    
    We do not believe that these final rule costs will be a significant 
impact to small entity operators because, even for the high-cost case, 
the compliance costs of this proposal to operators would only be less 
than one percent of annual revenue for each of the small business part 
23 manufacturers. Again, the only comment regarding small entities for 
the NPRM was the noted comment from Sino Swearingen.
    Therefore, as the FAA Administrator, I certify that this final rule 
will not have a significant economic impact on a substantial number of 
small entities.

International Trade Impact Assessment

    The Trade Agreements Act of 1979 (Pub. L. 96-39), as amended by the 
Uruguay Round Agreements Act (Pub. L. 103-465), prohibits Federal 
agencies from establishing standards or engaging in related activities 
that create unnecessary obstacles to the foreign commerce of the United 
States. Pursuant to these Acts, the establishment of standards is not 
considered an unnecessary obstacle to the foreign commerce of the 
United States, so long as the standard has a legitimate domestic 
objective, such as the protection of safety, and does not operate in a 
manner that excludes imports that meet this objective. The statute also 
requires consideration of international standards and, where 
appropriate, that they be the basis for U.S. standards.
    The FAA has assessed the potential effect of this final rule and 
determined that the standards are necessary for aviation safety and 
will not create unnecessary obstacles to the foreign commerce of the 
United States.

Unfunded Mandates Assessment

    Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires each Federal agency to prepare a written statement 
assessing the effects of any Federal mandate in a proposed or final 
agency rule that may result in an expenditure of $100 million or more 
(in 1995 dollars) in any one year by State, local, and Tribal 
governments, in the aggregate, or by the private sector; such a mandate 
is deemed to be a ``significant regulatory action.''
    The FAA currently uses an inflation-adjusted value of $140.8 
million in lieu of $100 million. This final rule does not contain such 
a mandate; therefore, the requirements of Title II of the Act do not 
apply.

Executive Order 13132, Federalism

    The FAA has analyzed this final rule under the principles and 
criteria of Executive Order 13132, Federalism. We determined that this 
action will not have a substantial direct effect on the States, or the 
relationship between the Federal Government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government; therefore, it does not have federalism implications.

Regulations Affecting Intrastate Aviation in Alaska

    Section 1205 of the FAA Reauthorization Act of 1996 (110 Stat. 
3213) requires the FAA, when modifying its regulations in a manner 
affecting intrastate aviation in Alaska, to consider the extent to 
which Alaska is not served by transportation modes other than aviation, 
and to establish appropriate regulatory distinctions. In the NPRM, we 
requested comments on whether the proposed rule should apply 
differently to intrastate operations in Alaska. We did not receive any 
comments. We have determined, based on the administrative record of 
this rulemaking, that there is no need to make any regulatory 
distinctions applicable to intrastate aviation in Alaska.

Environmental Analysis

    FAA Order 1050.1E identifies FAA actions that are categorically 
excluded from preparation of an environmental assessment or 
environmental impact statement under the National Environmental Policy 
Act in the absence of extraordinary circumstances. The FAA has 
determined this rulemaking action qualifies for the categorical 
exclusion identified in paragraph 312(f) and involves no extraordinary 
circumstances.

Regulations That Significantly Affect Energy Supply, Distribution, or 
Use

    The FAA analyzed this final rule under Executive Order 13211, 
Actions Concerning Regulations that Significantly Affect Energy Supply, 
Distribution, or Use (May 18, 2001). We have determined that it is not 
a ``significant energy action'' under the executive order because it is 
not a ``significant regulatory action,'' and it is not likely to have a 
significant adverse effect on the supply, distribution, or use of 
energy.

Availability of Rulemaking Documents

    You can get an electronic copy of rulemaking documents using the 
Internet by--
    1. Searching the Federal eRulemaking Portal (http://www.regulations.gov);
    2. Visiting the FAA's Regulations and Policies Web page at http://www.faa.gov/regulations_policies/ or
    3. Accessing the Government Printing Office's Web page at http://www.gpoaccess.gov/fr/index.html.
    You can also get a copy by sending a request to the Federal 
Aviation Administration, Office of Rulemaking,

[[Page 75753]]

ARM-1, 800 Independence Avenue SW., Washington, DC 20591, or by calling 
(202) 267-9680. Make sure to identify the notice, amendment, or docket 
number of this rulemaking.
    Anyone is able to search the electronic form of all comments 
received into any of our dockets by the name of the individual 
submitting the comment (or by signing the comment, if submitted on 
behalf of an association, business, labor union, etc.). You may review 
DOT's complete Privacy Act statement in the Federal Register published 
on April 11, 2000 (Volume 65, Number 70; Pages 19477-78) or you may 
visit http://DocketsInfo.dot.gov.

Small Business Regulatory Enforcement Fairness Act

    The Small Business Regulatory Enforcement Fairness Act (SBREFA) of 
1996 requires FAA to comply with small entity requests for information 
or advice about compliance with statutes and regulations within its 
jurisdiction. If you are a small entity and you have a question 
regarding this document, you may contact your local FAA official, or 
the person listed under the FOR FURTHER INFORMATION CONTACT heading at 
the beginning of the preamble. You can find out more about SBREFA on 
the Internet at http://www.faa.gov/regulations_policies/rulemaking/sbre_act/.

List of Subjects in 14 CFR Part 23

    Aviation safety, Signs, Symbols, Aircraft.

The Amendments

    In consideration of the foregoing, the Federal Aviation 
Administration amends Chapter I of Title 14, Code of Federal 
Regulations, as follows:

PART 23--AIRWORTHINESS STANDARDS; NORMAL, UTILITY, ACROBATIC, AND 
COMMUTER CATEGORY AIRPLANES

0
1. The authority citation for part 23 continues to read as follows:

    Authority: 49 U.S.C. 106(G), 40113, 44701-44702, 44704.

0
2. Amend Sec.  23.3 by revising the first sentence in paragraph (d) to 
read as follows:

Sec.  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. * * *
* * * * *

0
3. Amend Sec.  23.45 by revising the introductory text of paragraph (h) 
to read as follows:

Sec.  23.45  General.

* * * * *
    (h) For multiengine jets weighing over 6,000 pounds in the normal, 
utility, and acrobatic category and commuter category airplanes, the 
following also apply:
* * * * *

0
4. Amend Sec.  23.49 by revising the section heading and the 
introductory text of paragraphs (a) and (c) to read as follows:

Sec.  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--
* * * * *

0
5. Amend Sec.  23.51 by revising paragraph (b)(1) introductory text and 
paragraph (c) introductory text to read as follows:

Sec.  23.51  Takeoff speeds.

* * * * *
    (b) * * *
    (1) For multiengine airplanes, the highest of--
* * * * *
    (c) For normal, utility, and acrobatic category multiengine jets of 
more than 6,000 pounds maximum weight and commuter category airplanes, 
the following apply:
* * * * *

0
6. Amend Sec.  23.53 by revising paragraph (c) to read as follows:

Sec.  23.53  Takeoff performance.

* * * * *
    (c) For normal, utility, and acrobatic category multiengine jets of 
more than 6,000 pounds maximum weight and commuter category airplanes, 
takeoff performance, as required by Sec. Sec.  23.55 through 23.59, 
must be determined with the operating engine(s) within approved 
operating limitations.

0
7. Amend Sec.  23.55 by revising the introductory text to read as 
follows:

Sec.  23.55  Accelerate-stop distance.

    For normal, utility, and acrobatic category multiengine jets of 
more than 6,000 pounds maximum weight and commuter category airplanes, 
the accelerate-stop distance must be determined as follows:
* * * * *

0
8. Amend Sec.  23.57 by revising the introductory text to read as 
follows:

Sec.  23.57  Takeoff path.

    For normal, utility, and acrobatic category multiengine jets of 
more than 6,000 pounds maximum weight and commuter category airplanes, 
the takeoff path is as follows:
* * * * *

0
9. Amend Sec.  23.59 by revising the introductory text to read as 
follows:

Sec.  23.59  Takeoff distance and takeoff run.

    For normal, utility, and acrobatic category multiengine jets of 
more than 6,000 pounds maximum weight and commuter category airplanes, 
the takeoff distance and, at the option of the applicant, the takeoff 
run, must be determined.
* * * * *

0
10. Amend Sec.  23.61 by revising the introductory text to read as 
follows:

Sec.  23.61  Takeoff flight path.

    For normal, utility, and acrobatic category multiengine jets of 
more than 6,000 pounds maximum weight and commuter category airplanes, 
the takeoff flight path must be determined as follows:
* * * * *

0
11. Amend Sec.  23.63 by revising the introductory text of paragraphs 
(c) and (d) to read as follows:

Sec.  23.63  Climb: General.

* * * * *
    (c) For reciprocating engine-powered airplanes of more than 6,000 
pounds maximum weight, single-engine turbines, and multiengine turbine 
airplanes of 6,000 pounds or less maximum weight in the normal, 
utility, and acrobatic category, compliance must be shown at weights as 
a function of airport altitude and ambient temperature, within the 
operational limits established for takeoff and landing, respectively, 
with--
* * * * *
    (d) For multiengine turbine airplanes over 6,000 pounds maximum 
weight in the normal, utility, and acrobatic category and commuter 
category airplanes, compliance must be shown at weights as a function 
of airport altitude and ambient temperature within the operational 
limits established for takeoff and landing, respectively, with--
* * * * *

0
12. Amend Sec.  23.65 by revising paragraph (b) to read as follows:

[[Page 75754]]

Sec.  23.65  Climb: All engines operating.

* * * * *
    (b) Each normal, utility, and acrobatic category reciprocating 
engine-powered airplane of more than 6,000 pounds maximum weight, 
single-engine turbine, and multiengine turbine airplanes of 6,000 
pounds or less maximum weight in the normal, utility, and acrobatic 
category must have a steady gradient of climb after takeoff of at least 
4 percent with
* * * * *

0
13. Amend Sec.  23.67 by revising paragraph (b) introductory text and 
(b)(1) introductory text, redesignating paragraph (c) as paragraph (d), 
revising newly redesignated paragraph (d) introductory text, and adding 
new paragraph (c) to read as follows:

Sec.  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 
turbopropeller-powered airplanes in the normal, utility, and acrobatic 
category--
    (1) The steady gradient of climb at an altitude of 400 feet above 
the takeoff must be no less than 1 percent with the--
* * * * *
    (c) For normal, utility, and acrobatic category jets of 6,000 
pounds or less maximum weight--
    (1) The steady gradient of climb at an altitude of 400 feet above 
the takeoff must be no less than 1.2 percent with the--
    (i) Critical engine inoperative;
    (ii) Remaining engine(s) at takeoff power;
    (iii) Landing gear retracted;
    (iv) Wing flaps in the takeoff position(s); and
    (v) Climb speed equal to that achieved at 50 feet in the 
demonstration of Sec.  23.53.
    (2) The steady gradient of climb may not be less than 0.75 percent 
at an altitude of 1,500 feet above the takeoff surface, or landing 
surface, as appropriate, with the--
    (i) Critical engine inoperative;
    (ii) Remaining engine(s) at not more than maximum continuous power;
    (iii) Landing gear retracted;
    (iv) Wing flaps retracted; and
    (v) Climb speed not less than 1.2 VS1.
    (d) For jets over 6,000 pounds maximum weight in the normal, 
utility and acrobatic category and commuter category airplanes, the 
following apply:
* * * * *

0
14. Revise Sec.  23.73 to read as follows:

Sec.  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 Sec.  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 Sec.  23.149(c), and 1.3 
VS1.
    (c) For normal, utility, and acrobatic category jets of more than 
6,000 pounds maximum weight and commuter category airplanes, the 
reference landing approach speed, VREF, may not be less than 
the greater of 1.05 VMC, determined in Sec.  23.149(c), and 
1.3 VS1.

0
15. Amend Sec.  23.77 by revising the introductory text of paragraphs 
(b) and (c) to read as follows:

Sec.  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--
* * * * *

0
16. Amend Sec.  23.177 by revising paragraphs (a), (b), and (d) to read 
as follows:

Sec.  23.177  Static directional and lateral stability.

    (a)(1) The static directional stability, as shown by the tendency 
to recover from a wings level sideslip with the rudder free, must be 
positive for any landing gear and flap position appropriate to the 
takeoff, climb, cruise, approach, and landing configurations. This must 
be shown with symmetrical power up to maximum continuous power, and at 
speeds from 1.2 VS1 up to VFE, VLE, 
VNO, VFC/MFC, whichever is 
appropriate.
    (2) The angle of sideslip for these tests must be appropriate to 
the type of airplane. The rudder pedal force must not reverse at larger 
angles of sideslip, up to that at which full rudder is used or a 
control force limit in Sec.  23.143 is reached, whichever occurs first, 
and at speeds from 1.2 VS1 to VO.
    (b)(1) The static lateral stability, as shown by the tendency to 
raise the low wing in a sideslip with the aileron controls free, may 
not be negative for any landing gear and flap position appropriate to 
the takeoff, climb, cruise, approach, and landing configurations. This 
must be shown with symmetrical power from idle up to 75 percent of 
maximum continuous power at speeds from 1.2 VS1 in the 
takeoff configuration(s) and at speeds from 1.3 VS1 in other 
configurations, up to the maximum allowable airspeed for the 
configuration being investigated (VFE, VLE, 
VNO, VFC/MFC, whichever is 
appropriate) in the takeoff, climb, cruise, descent, and approach 
configurations. For the landing configuration, the power must be that 
necessary to maintain a 3-degree angle of descent in coordinated 
flight.
    (2) The static lateral stability may not be negative at 1.2 
VS1 in the takeoff configuration, or at 1.3 VS1 
in other configurations.
    (3) The angel of sideslip for these tests must be appropriate to 
the type of airplane, but in no case may the constant heading sideslip 
angle be less than that obtainable with a 10 degree bank or, if less, 
the maximum bank angle obtainable with full rudder deflection or 150 
pound rudder force.
* * * * *
    (d)(1) In straight, steady slips at 1.2 VS1 for any 
landing gear and flap position appropriate to the takeoff, climb, 
cruise, approach, and landing configurations, and for any symmetrical 
power conditions up to 50 percent of maximum continuous power, the 
aileron and rudder control movements and forces must increase steadily, 
but not necessarily in constant proportion, as the angle of sideslip is 
increased up to the maximum appropriate to the type of airplane.
    (2) At larger slip angles, up to the angle at which the full rudder 
or aileron control is used or a control force limit contained in Sec.  
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

[[Page 75755]]

appropriate for the airplane may not result in uncontrollable flight 
characteristics.

0
17. Amend Sec.  23.181 by revising paragraph (b) to read as follows:

Sec.  23.181  Dynamic stability.

* * * * *
    (b) Any combined lateral-directional oscillations (Dutch roll) 
occurring between the stalling speed and the maximum allowable speed 
(VFE, VLE, VN0, VFC/
MFC) appropriate to the configuration of the airplane with 
the primary controls in both free and fixed position, must be damped to 
1/10 amplitude in:
    (1) Seven (7) cycles below 18,000 feet and
    (2) Thirteen (13) cycles from 18,000 feet to the certified maximum 
altitude.
* * * * *

0
18. Amend Sec.  23.201 by revising paragraph (d), by revising and 
redesignating current paragraph (e) as paragraph (f), and by adding a 
new paragraph (e) to read as follows:

Sec.  23.201  Wings level stall.

* * * * *
    (d) During the entry into and the recovery from the maneuver, it 
must be possible to prevent more than 15 degrees of roll or yaw by the 
normal use of controls except as provided for in paragraph (e) of this 
section.
    (e) For airplanes approved with a maximum operating altitude at or 
above 25,000 feet during the entry into and the recovery from stalls 
performed at or above 25,000 feet, it must be possible to prevent more 
than 25 degrees of roll or yaw by the normal use of controls.
    (f) Compliance with the requirements of this section must be shown 
under the following conditions:
    (1) Wing flaps: Retracted, fully extended, and each intermediate 
normal operating position, as appropriate for the phase of flight.
    (2) Landing gear: Retracted and extended as appropriate for the 
altitude.
    (3) Cowl flaps: Appropriate to configuration.
    (4) Spoilers/speedbrakes: Retracted and extended unless they have 
no measureable effect at low speeds.
    (5) Power:
    (i) Power/Thrust off; and
    (ii) For reciprocating engine powered airplanes: 75 percent of 
maximum continuous power. However, if the power-to-weight ratio at 75 
percent of maximum continuous power results in nose-high attitudes 
exceeding 30 degrees, the test may be carried out with the power 
required for level flight in the landing configuration at maximum 
landing weight and a speed of 1.4 VSO, except that the power 
may not be less than 50 percent of maximum continuous power; or
    (iii) For turbine engine powered airplanes: The maximum engine 
thrust, except that it need not exceed the thrust necessary to maintain 
level flight at 1.5 VS1 (where VS1 corresponds to 
the stalling speed with flaps in the approach position, the landing 
gear retracted, and maximum landing weight).
    (6) Trim: At 1.5 VS1 or the minimum trim speed, 
whichever is higher.
    (7) Propeller: Full increase r.p.m. position for the power off 
condition.

0
19. Amend Sec.  23.203 by revising paragraph (c) to read as follows:

Sec.  23.203  Turning flight and accelerated turning stalls.

* * * * *
    (c) Compliance with the requirements of this section must be shown 
under the following conditions:
    (1) Wings flaps: Retracted, fully extended, and each intermediate 
normal operating position as appropriate for the phase of flight.
    (2) Landing gear: Retracted and extended as appropriate for the 
altitude.
    (3) Cowl flaps: Appropriate to configuration.
    (4) Spoilers/speedbrakes: Retracted and extended unless they have 
no measureable effect at low speeds.
    (5) Power:
    (i) Power/Thrust off; and
    (ii) For reciprocating engine powered airplanes: 75 percent of 
maximum continuous power. However, if the power-to-weight ratio at 75 
percent of maximum continuous power results in nose-high attitudes 
exceeding 30 degrees, the test may be carried out with the power 
required for level flight in the landing configuration at maximum 
landing weight and a speed of 1.4 VSO, except that the power 
may not be less than 50 percent of maximum continuous power; or
    (iii) For turbine engine powered airplanes: The maximum engine 
thrust, except that it need not exceed the thrust necessary to maintain 
level flight at 1.5 VS1 (where VS1 corresponds to 
the stalling speed with flaps in the approach position, the landing 
gear retracted, and maximum landing weight).
    (6) Trim: The airplane trimmed at 1.5 VS1.
    (7) Propeller: Full increase rpm position for the power off 
condition.

0
20. Revise Sec.  23.251 to read as follows:

Sec.  23.251  Vibration and buffeting.

    (a) There must be no vibration or buffeting severe enough to result 
in structural damage, and each part of the airplane must be free from 
excessive vibration, under any appropriate speed and power conditions 
up to VD/MD, or VDF/MDF for 
turbojets. In addition, there must be no buffeting in any normal flight 
condition, including configuration changes during cruise, severe enough 
to interfere with the satisfactory control of the airplane or cause 
excessive fatigue to the flight crew. Stall warning buffeting within 
these limits is allowable.
    (b) There must be no perceptible buffeting condition in the cruise 
configuration in straight flight at any speed up to VMO/
MMO, except stall buffeting, which is allowable.
    (c) For airplanes with MD greater than M 0.6 or a 
maximum operating altitude greater than 25,000 feet, the positive 
maneuvering load factors at which the onset of perceptible buffeting 
occurs must be determined with the airplane in the cruise configuration 
for the ranges of airspeed or Mach number, weight, and altitude for 
which the airplane is to be certificated. The envelopes of load factor, 
speed, altitude, and weight must provide a sufficient range of speeds 
and load factors for normal operations. Probable inadvertent excursions 
beyond the boundaries of the buffet onset envelopes may not result in 
unsafe conditions.

0
21. Amend Sec.  23.253 by revising paragraphs (b)(1) and (b)(2), and by 
adding new paragraphs (b)(3) and (d) to read as follows:

Sec.  23.253  High speed characteristics.

* * * * *
    (b) * * *
    (1) Exceptional piloting strength or skill;
    (2) Exceeding VD/MD, or VDF/
MDF for turbojets, the maximum speed shown under Sec.  
23.251, or the structural limitations; and
    (3) Buffeting that would impair the pilot's ability to read the 
instruments or to control the airplane for recovery.
* * * * *
    (d) Maximum speed for stability characteristics, VFC/MFC. 
VFC/MFC may not be less than a speed midway 
between VMO/MMO and VDF/MDF 
except that, for altitudes where Mach number is the limiting factor, 
MFC need not exceed the Mach number at which effective speed 
warning occurs.

0
22. Section 23.255 is added to subpart B to read as follows:

Sec.  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

[[Page 75756]]

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-of-trim 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 Sec.  23.655(b) for adjustable 
stabilizers; or
    (2) The maximum mistrim that can be sustained by the autopilot 
while maintaining level flight in the high speed cruising condition.
    (b) In the out-of-trim condition specified in paragraph (a) of this 
section, when the normal acceleration is varied from +l g to the 
positive and negative values specified in paragraph (c) of this 
section, the following apply:
    (1) The stick force versus g curve must have a positive slope at 
any speed up to and including VFC/MFC; and
    (2) At speeds between VFC/MFC and 
VDF/MDF, the direction of the primary 
longitudinal control force may not reverse.
    (c) Except as provided in paragraphs (d) and (e) of this section, 
compliance with the provisions of paragraph (a) of this section must be 
demonstrated in flight over the acceleration range as follows:
    (1) -1 g to +2.5 g; or
    (2) 0 g to 2.0 g, and extrapolating by an acceptable method to -1 g 
and +2.5 g.
    (d) If the procedure set forth in paragraph (c)(2) of this section 
is used to demonstrate compliance and marginal conditions exist during 
flight test with regard to reversal of primary longitudinal control 
force, flight tests must be accomplished from the normal acceleration 
at which a marginal condition is found to exist to the applicable limit 
specified in paragraph (b)(1) of this section.
    (e) During flight tests required by paragraph (a) of this section, 
the limit maneuvering load factors, prescribed in Sec. Sec.  23.333(b) 
and 23.337, need not be exceeded. In addition, the entry speeds for 
flight test demonstrations at normal acceleration values less than 1 g 
must be limited to the extent necessary to accomplish a recovery 
without exceeding VDF/MDF.
    (f) In the out-of-trim condition specified in paragraph (a) of this 
section, it must be possible from an overspeed condition at 
VDF/MDF to produce at least 1.5 g for recovery by 
applying not more than 125 pounds of longitudinal control force using 
either the primary longitudinal control alone or the primary 
longitudinal control and the longitudinal trim system. If the 
longitudinal trim is used to assist in producing the required load 
factor, it must be shown at VDF/MDF that the 
longitudinal trim can be actuated in the airplane nose-up direction 
with the primary surface loaded to correspond to the least of the 
following airplane nose-up control forces:
    (1) The maximum control forces expected in service, as specified in 
Sec. Sec.  23.301 and 23.397.
    (2) The control force required to produce 1.5 g.
    (3) The control force corresponding to buffeting or other phenomena 
of such intensity that it is a strong deterrent to further application 
of primary longitudinal control force.

0
23. Amend Sec.  23.561 by adding new paragraph (e)(1), and adding and 
reserving paragraph (e)(2), to read as follows:

Sec.  23.561  General.

* * * * *
    (e) * * *
    (1) For engines mounted inside the fuselage, aft of the cabin, it 
must be shown by test or analysis that the engine and attached 
accessories, and the engine mounting structure--
    (i) Can withstand a forward acting static ultimate inertia load 
factor of 18.0 g plus the maximum takeoff engine thrust; or
    (ii) The airplane structure is designed to preclude the engine and 
its attached accessories from entering or protruding into the cabin 
should the engine mounts fail.
    (2) [Reserved]

0
24. Amend Sec.  23.562 by revising paragraphs (a) introductory text, 
(b) introductory text, and (c)(5)(ii) to read as follows:

Sec.  23.562  Emergency landing dynamic conditions.

    (a) Each seat/restraint system for use in a normal, utility, or 
acrobatic category airplane, or in a commuter category jet airplane, 
must be designed to protect each occupant during an emergency landing 
when--
* * * * *
    (b) Except for those seat/restraint systems that are required to 
meet paragraph (d) of this section, each seat/restraint system for crew 
or passenger occupancy in a normal, utility, or acrobatic category 
airplane, or in a commuter category jet airplane, must successfully 
complete dynamic tests or be demonstrated by rational analysis 
supported by dynamic tests, in accordance with each of the following 
conditions. These tests must be conducted with an occupant simulated by 
an anthropomorphic test dummy (ATD) defined by 49 CFR part 572, subpart 
B, or an FAA-approved equivalent, with a nominal weight of 170 pounds 
and seated in the normal upright position.
* * * * *
    (c) * * *
    (5) * * *
    (ii) The value of HIC is defined as--
    [GRAPHIC] [TIFF OMITTED] TR02DE11.083
    
Where--

t1 is the initial integration time, expressed in seconds, 
t2 is the final integration time, expressed in seconds, 
and a(t) is the total acceleration vs. time curve for the head 
strike expressed as a multiple of g (units of gravity).
* * * * *

0
25. Amend Sec.  23.571 by adding a new paragraph (d) to read as 
follows:

Sec.  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 
Sec.  23.573(b) must be conducted.

0
26. Amend Sec.  23.629 by revising paragraphs (b)(1), (b)(3), (b)(4), 
and (c) to read as follows:

[[Page 75757]]

Sec.  23.629  Flutter.

* * * * *
    (b) * * *
    (1) Proper and adequate attempts to induce flutter have been made 
within the speed range up to VD/MD, or 
VDF/MDF for jets;
* * * * *
    (3) A proper margin of damping exists at VD/
MD, or VDF/MDF for jets; and
    (4) As VD/MD (or VDF/
MDF for jets) is approached, there is no large or rapid 
reduction in damping.
    (c) Any rational analysis used to predict freedom from flutter, 
control reversal and divergence must cover all speeds up to 1.2 
VD/1.2 MD, limited to Mach 1.0 for subsonic 
airplanes.
* * * * *

0
27. Amend Sec.  23.703 by revising the introductory text and adding a 
new paragraph (c) to read as follows:

Sec.  23.703  Takeoff warning system.

    For all airplanes with a maximum weight more than 6,000 pounds and 
all jets, unless it can be shown that a lift or longitudinal trim 
device that affects the takeoff performance of the airplane would not 
give an unsafe takeoff configuration when selected out of an approved 
takeoff position, a takeoff warning system must be installed and meet 
the following requirements:
* * * * *
    (c) For the purpose of this section, an unsafe takeoff 
configuration is the inability to rotate or the inability to prevent an 
immediate stall after rotation.

0
28. Amend Sec.  23.735 by revising paragraph (e) to read as follows:

Sec.  23.735  Brakes.

* * * * *
    (e) For airplanes required to meet Sec.  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 WV\2\/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 Sec.  23.51(c)(1);
N = Number of main wheels with brakes.

0
29. Amend Sec.  23.777 by revising paragraph (d) to read as follows:

Sec.  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 turbine-
powered airplanes). Power (thrust) levers must be easily 
distinguishable from other controls, and provide for accurate, 
consistent operation. Carburetor heat or alternate air control must be 
to the left of the throttle or at least eight inches from the mixture 
control when located other than on a pedestal. Carburetor heat or 
alternate air control, when located on a pedestal, must be aft or below 
the power (thrust) lever. Supercharger controls must be located below 
or aft of the propeller controls. Airplanes with tandem seating or 
single-place airplanes may utilize control locations on the left side 
of the cabin compartment; however, location order from left to right 
must be power (thrust) lever, propeller (rpm control), and mixture 
control.
* * * * *

0
30. Amend Sec.  23.807 by adding a new paragraph (e)(3) to read as 
follows:

Sec.  23.807  Emergency exits.

* * * * *
    (e) * * *
    (3) In lieu of paragraph (e)(2) of this section, if any side 
exit(s) cannot be above the waterline, a device may be placed at each 
of such exit(s) prior to ditching. This device must slow the inflow of 
water when such exit(s) is opened with the airplane ditched. For 
commuter category airplanes, the clear opening of such exit(s) must 
meet the requirements defined in paragraph (d) of this section.

0
31. Amend Sec.  23.831 by adding paragraphs (c) and (d) to read as 
follows:

Sec.  23.831  Ventilation.

* * * * *
    (c) For jet pressurized airplanes that operate at altitudes above 
41,000 feet, under normal operating conditions and in the event of any 
probable failure conditions of any system which would adversely affect 
the ventilating air, the ventilation system must provide reasonable 
passenger comfort. The ventilation system must also provide a 
sufficient amount of uncontaminated air to enable the flight crew 
members to perform their duties without undue discomfort or fatigue. 
For normal operating conditions, the ventilation system must be 
designed to provide each occupant with at least 0.55 pounds of fresh 
air per minute. In the event of the loss of one source of fresh air, 
the supply of fresh airflow may not be less than 0.4 pounds per minute 
for any period exceeding five minutes.
    (d) For jet pressurized airplanes that operate at altitudes above 
41,000 feet, other probable and improbable Environmental Control System 
failure conditions that adversely affect the passenger and flight crew 
compartment environmental conditions may not affect flight crew 
performance so as to result in a hazardous condition, and no occupant 
shall sustain permanent physiological harm.

0
32. Amend Sec.  23.841 by revising paragraphs (a) and (b)(6), and by 
adding paragraphs (c) and (d) to read as follows:

Sec.  23.841  Pressurized cabins.

    (a) If certification for operation above 25,000 feet is requested, 
the airplane must be able to maintain a cabin pressure altitude of not 
more than 15,000 feet, in the event of any probable failure condition 
in the pressurization system. During decompression, the cabin altitude 
may not exceed 15,000 feet for more than 10 seconds and 25,000 feet for 
any duration.
    (b) * * *
    (6) Warning indication at the pilot station to indicate when the 
safe or preset pressure differential is exceeded and when a cabin 
pressure altitude of 10,000 feet is exceeded. The 10,000 foot cabin 
altitude warning may be increased up to 15,000 feet for operations from 
high altitude airfields (10,000 to 15,000 feet) provided:
    (i) The landing or the take off modes (normal or high altitude) are 
clearly indicated to the flight crew.
    (ii) Selection of normal or high altitude airfield mode requires no 
more than one flight crew action and goes to normal airfield mode at 
engine stop.
    (iii) The pressurization system is designed to ensure cabin 
altitude does not exceed 10,000 feet when in flight above flight level 
(FL) 250.
    (iv) The pressurization system and cabin altitude warning system is 
designed to ensure cabin altitude warning at 10,000 feet when in flight 
above FL250.
* * * * *
    (c) If certification for operation above 41,000 feet and not more 
than 45,000 feet is requested--

[[Page 75758]]

    (1) The airplane must prevent cabin pressure altitude from 
exceeding the following after decompression from any probable 
pressurization system failure in conjunction with any undetected, 
latent pressurization system failure condition:
    (i) If depressurization analysis shows that the cabin altitude does 
not exceed 25,000 feet, the pressurization system must prevent the 
cabin altitude from exceeding the cabin altitude-time history shown in 
Figure 1 of this section.
    (ii) Maximum cabin altitude is limited to 30,000 feet. If cabin 
altitude exceeds 25,000 feet, the maximum time the cabin altitude may 
exceed 25,000 feet is 2 minutes; time starting when the cabin altitude 
exceeds 25,000 feet and ending when it returns to 25,000 feet.
    (2) The airplane must prevent cabin pressure altitude from 
exceeding the following after decompression from any single 
pressurization system failure in conjunction with any probable fuselage 
damage:
    (i) If depressurization analysis shows that the cabin altitude does 
not exceed 37,000 feet, the pressurization system must prevent the 
cabin altitude from exceeding the cabin altitude-time history shown in 
Figure 2 of this section.
    (ii) Maximum cabin altitude is limited to 40,000 feet. If cabin 
altitude exceeds 37,000 feet, the maximum time the cabin altitude may 
exceed 25,000 feet is 2 minutes; time starting when the cabin altitude 
exceeds 25,000 feet and ending when it returns to 25,000 feet.
    (3) In showing compliance with paragraphs (c)(1) and (c)(2) of this 
section, it may be assumed that an emergency descent is made by an 
approved emergency procedure. A 17-second flight crew recognition and 
reaction time must be applied between cabin altitude warning and the 
initiation of an emergency descent. Fuselage structure, engine and 
system failures are to be considered in evaluating the cabin 
decompression.
[GRAPHIC] [TIFF OMITTED] TR02DE11.084

[[Page 75759]]

[GRAPHIC] [TIFF OMITTED] TR02DE11.085

    (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 Sec.  
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.

0
33. Amend Sec.  23.853 by revising paragraph (d)(2) to read as follows:

Sec.  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.
* * * * *
0
34. Add a new Sec.  23.856 to read as follows:

Sec.  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 Sec.  
23.853(d)(3)(v).

0
35. Amend Sec.  23.903 by adding paragraph (b)(3) to read as follows:

Sec.  23.903  Engines.

* * * * *
    (b) * * *
    (3) For engines embedded in the fuselage behind the cabin, the 
effects of a fan exiting forward of the inlet case (fan disconnect) 
must be addressed, the passengers must be protected, and the airplane 
must be controllable to allow for continued safe flight and landing.
* * * * *

0
36. Amend Sec.  23.1165 by revising paragraph (f) to read as follows:

Sec.  23.1165  Engine ignition systems.

* * * * *
    (f) In addition, for commuter category airplanes, each turbine 
engine ignition system must be an essential electrical load.

0
37. Amend Sec.  23.1193 by revising paragraph (g) to read as follows:

Sec.  23.1193  Cowling and nacelle.

* * * * *
    (g) In addition, for all airplanes with engine(s) embedded in the 
fuselage or in pylons on the aft fuselage, the airplane must be 
designed so that no fire originating in any engine compartment can 
enter, either through openings or by burn-through, any other region 
where it would create additional hazards.

0
38. Amend Sec.  23.1195 by revising the introductory text of paragraph 
(a) and by revising paragraph (a)(2) to read as follows:

Sec.  23.1195  Fire extinguishing systems.

    (a) For all airplanes with engine(s) embedded in the fuselage or in 
pylons on the aft fuselage, fire extinguishing

[[Page 75760]]

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.
* * * * *

0
39. Amend Sec.  23.1197 by revising the introductory text to read as 
follows:

Sec.  23.1197  Fire extinguishing agents.

    For all airplanes with engine(s) embedded in the fuselage or in 
pylons on the aft fuselage the following applies:
* * * * *

0
40. Amend Sec.  23.1199 by revising the introductory text to read as 
follows:

Sec.  23.1199  Extinguishing agent containers.

    For all airplanes with engine(s) embedded in the fuselage or in 
pylons on the aft fuselage the following applies:
* * * * *

0
41. Amend Sec.  23.1201 by revising the introductory text to read as 
follows:

Sec.  23.1201  Fire extinguishing systems materials.

    For all airplanes with engine(s) embedded in the fuselage or in 
pylons on the aft fuselage the following applies:
* * * * *

0
42. Revise Sec.  23.1301 by revising paragraphs (b) and (c) and by 
removing paragraph (d) to read as follows:

Sec.  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.
* * * * *

0
43. Amend Sec.  23.1303 by revising paragraph (c) to read as follows:

Sec.  23.1303  Flight and navigation instruments.

* * * * *
    (c) A magnetic direction indicator.
* * * * *

0
44. Revise Sec.  23.1309 to read as follows:

Sec.  23.1309  Equipment, systems, and installations.

    The requirements of this section, except as identified in 
paragraphs (a) through (d), are applicable, in addition to specific 
design requirements of part 23, to any equipment or system as installed 
in the airplane. This section is a regulation of general requirements 
and does not supersede any requirements contained in another section of 
part 23.
    (a) The airplane equipment and systems must be designed and 
installed so that:
    (1) Those required for type certification or by operating rules 
perform as intended under the airplane operating and environmental 
conditions, including the indirect effects of lightning strikes.
    (2) Any equipment and system does not adversely affect the safety 
of the airplane or its occupants, or the proper functioning of those 
covered by paragraph (a)(1) of this section.
    (b) Minor, major, hazardous, or catastrophic failure condition(s), 
which occur during Type Inspection Authorization or FAA flight-
certification testing, must have root cause analysis and corrective 
action.
    (c) The airplane systems and associated components considered 
separately and in relation to other systems, must be designed and 
installed so that:
    (1) Each catastrophic failure condition is extremely improbable and 
does not result from a single failure;
    (2) Each hazardous failure condition is extremely remote; and
    (3) Each major failure condition is remote.
    (d) Information concerning an unsafe system operating condition 
must be provided in a timely manner to the crew to enable them to take 
appropriate corrective action. An appropriate alert must be provided if 
immediate pilot awareness and immediate or subsequent corrective action 
is required. Systems and controls, including indications and 
annunciations, must be designed to minimize crew errors which could 
create additional hazards.

0
45. Add a new Sec.  23.1310 to read as follows:

Sec.  23.1310  Power source capacity and distribution.

    (a) Each installation whose functioning is required for type 
certification or under operating rules and that requires a power supply 
is an ``essential load'' on the power supply. The power sources and the 
system must be able to supply the following power loads in probable 
operating combinations and for probable durations:
    (1) Loads connected to the system with the system functioning 
normally.
    (2) Essential loads, after failure of any one prime mover, power 
converter, or energy storage device.
    (3) Essential loads after failure of--
    (i) Any one engine on two-engine airplanes; and
    (ii) Any two engines on airplanes with three or more engines.
    (4) Essential loads for which an alternate source of power is 
required, after any failure or malfunction in any one power supply 
system, distribution system, or other utilization system.
    (b) In determining compliance with paragraphs (a)(2) and (3) of 
this section, the power loads may be assumed to be reduced under a 
monitoring procedure consistent with safety in the kinds of operation 
authorized. Loads not required in controlled flight need not be 
considered for the two-engine-inoperative condition on airplanes with 
three or more engines.

0
46. Amend Sec.  23.1311 by revising paragraphs (a)(5), (a)(6), (a)(7), 
and paragraph (b) to read as follows:

Sec.  23.1311  Electronic display instrument systems.

    (a) * * *
    (5) For certification for Instrument Flight Rules (IFR) operations, 
have an independent magnetic direction indicator and either an 
independent secondary mechanical altimeter, airspeed indicator, and 
attitude instrument or an electronic display parameters for the 
altitude, airspeed, and attitude that are independent from the 
airplane's primary electrical power system. These secondary instruments 
may be installed in panel positions that are displaced from the primary 
positions specified by Sec.  23.1321(d), but must be located where they 
meet the pilot's visibility requirements of Sec.  23.1321(a).
    (6) Incorporate sensory cues that provide a quick glance sense of 
rate and, where appropriate, trend information to the parameter being 
displayed to the pilot.
    (7) Incorporate equivalent visual displays of the instrument 
markings required by Sec. Sec.  23.1541 through 23.1553, or visual 
displays that alert the pilot to abnormal operational values or 
approaches to established limitation values, for each parameter 
required to be displayed by this part.
    (b) The electronic display indicators, including their systems and 
installations, and considering other airplane systems, must be designed 
so that one display of information essential for continued safe flight 
and landing will be available within one second to the crew by a single 
pilot action or by automatic means for continued safe operation, after 
any single failure or probable combination of failures.
* * * * *

[[Page 75761]]

0
47. Amend Sec.  23.1323 by revising paragraph (e) to read as follows:

Sec.  23.1323  Airspeed indicating system.

* * * * *
    (e) In addition, for normal, utility, and acrobatic category 
multiengine jets of more than 6,000 pounds maximum weight and commuter 
category airplanes, each system must be calibrated to determine the 
system error during the accelerate-takeoff ground run. The ground run 
calibration must be determined--
    (1) From 0.8 of the minimum value of V1 to the maximum 
value of V2, considering the approved ranges of altitude and 
weight; and
    (2) The ground run calibration must be determined assuming an 
engine failure at the minimum value of V1.
* * * * *

0
48. Amend Sec.  23.1331 by revising paragraph (c) to read as follows:

Sec.  23.1331  Instruments using a power source.

* * * * *
    (c) For certification for Instrument Flight Rules (IFR) operations 
and for the heading, altitude, airspeed, and attitude, there must be at 
least:
    (1) Two independent sources of power (not driven by the same engine 
on multiengine airplanes), and a manual or an automatic means to select 
each power source; or
    (2) A separate display of parameters for heading, altitude, 
airspeed, and attitude that has a power source independent from the 
airplane's primary electrical power system.

0
49. Amend Sec.  23.1353 by revising paragraph (h) to read as follows:

Sec.  23.1353  Storage battery design and installation.

* * * * *
    (h)(1) In the event of a complete loss of the primary electrical 
power generating system, the battery must be capable of providing 
electrical power to those loads that are essential to continued safe 
flight and landing for:
    (i) At least 30 minutes for airplanes that are certificated with a 
maximum altitude of 25,000 feet or less; and
    (ii) At least 60 minutes for airplanes that are certificated with a 
maximum altitude over 25,000 feet.
    (2) The time period includes the time to recognize the loss of 
generated power and to take appropriate load shedding action.

0
50. Amend Sec.  23.1431, paragraph (a) to read as follows:

Sec.  23.1431  Electronic equipment.

    (a) In showing compliance with Sec.  23.1309(a), (b), and (c) with 
respect to radio and electronic equipment and their installations, 
critical environmental conditions must be considered.
* * * * *

0
51. Revise Sec.  23.1443 to read as follows:

Sec.  23.1443  Minimum mass flow of supplemental oxygen.

    (a) If the airplane is to be certified above 41,000 feet, a 
continuous flow oxygen system must be provided for each passenger.
    (b) If continuous flow oxygen equipment is installed, an applicant 
must show compliance with the requirements of either paragraphs (b)(1) 
and (b)(2) or paragraph (b)(3) of this section:
    (1) For each passenger, the minimum mass flow of supplemental 
oxygen required at various cabin pressure altitudes may not be less 
than the flow required to maintain, during inspiration and while using 
the oxygen equipment (including masks) provided, the following mean 
tracheal oxygen partial pressures:
    (i) At cabin pressure altitudes above 10,000 feet up to and 
including 18,500 feet, a mean tracheal oxygen partial pressure of 100mm 
Hg when breathing 15 liters per minute, Body Temperature, Pressure, 
Saturated (BTPS) and with a tidal volume of 700cc with a constant time 
interval between respirations.
    (ii) At cabin pressure altitudes above 18,500 feet up to and 
including 40,000 feet, a mean tracheal oxygen partial pressure of 
83.8mm Hg when breathing 30 liters per minute, BTPS, and with a tidal 
volume of 1,100cc with a constant time interval between respirations.
    (2) For each flight crewmember, the minimum mass flow may not be 
less than the flow required to maintain, during inspiration, a mean 
tracheal oxygen partial pressure of 149mm Hg when breathing 15 liters 
per minute, BTPS, and with a maximum tidal volume of 700cc with a 
constant time interval between respirations.
    (3) The minimum mass flow of supplemental oxygen supplied for each 
user must be at a rate not less than that shown in the following figure 
for each altitude up to and including the maximum operating altitude of 
the airplane.

[[Page 75762]]

[GRAPHIC] [TIFF OMITTED] TR02DE11.086

    (c) If demand equipment is installed for use by flight crewmembers, 
the minimum mass flow of supplemental oxygen required for each flight 
crewmember may not be less than the flow required to maintain, during 
inspiration, a mean tracheal oxygen partial pressure of 122mm Hg up to 
and including a cabin pressure altitude of 35,000 feet, and 95 percent 
oxygen between cabin pressure altitudes of 35,000 and 40,000 feet, when 
breathing 20 liters per minutes BTPS. In addition, there must be means 
to allow the flight crew to use undiluted oxygen at their discretion.
    (d) If first-aid oxygen equipment is installed, the minimum mass 
flow of oxygen to each user may not be less than 4 liters per minute, 
STPD. However, there may be a means to decrease this flow to not less 
than 2 liters per minute, STPD, at any cabin altitude. The quantity of 
oxygen required is based upon an average flow rate of 3 liters per 
minute per person for whom first-aid oxygen is required.
    (e) As used in this section:
    (1) BTPS means Body Temperature, and Pressure, Saturated (which is 
37 [deg]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 
[deg]C).
    (2) STPD means Standard, Temperature, and Pressure, Dry (which is 0 
[deg]C at 760mm Hg with no water vapor).

0
52. Amend Sec.  23.1445 by adding a new paragraph (c) to read as 
follows:

Sec.  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.

0
53. Amend Sec.  23.1447 by adding a new paragraph (g) to read as 
follows:

Sec.  23.1447  Equipment standards for oxygen dispensing units.

* * * * *
    (g) If the airplane is to be certified for operation above 41,000 
feet, a quick-donning 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.

0
54. Amend Sec.  23.1505 by revising paragraph (c) to read as follows:

Sec.  23.1505  Airspeed limitations.

* * * * *
    (c)(1) Paragraphs (a) and (b) of this section do not apply to 
turbine airplanes or to airplanes for which a design diving speed 
VD/MD is established under Sec.  23.335(b)(4). 
For those airplanes, a maximum operating limit speed (VMO/
MMO airspeed or Mach number, whichever is critical at a 
particular altitude) must be established as a speed that may not be 
deliberately exceeded in any regime of flight (climb, cruise, or 
descent) unless a higher speed is authorized for flight test or pilot 
training operations.
    (2) VMO/MMO must be established so that it is 
not greater than the design cruising speed VC/MC 
and so that it is sufficiently below VD/MD, or 
VDF/MDF for jets, and the maximum speed shown 
under Sec.  23.251 to make it highly improbable that the latter speeds 
will be inadvertently exceeded in operations.
    (3) The speed margin between VMO/MMO and 
VD/MD, or VDF/MDF for jets, 
may not be less than that determined under Sec.  23.335(b), or the 
speed margin found necessary in the flight tests conducted under Sec.  
23.253.

0
55. Amend Sec.  23.1545 by revising paragraph (d) to read as follows:

Sec.  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 Sec.  23.1505(c). 
For those airplanes, there must either be a maximum allowable airspeed 
indication

[[Page 75763]]

showing the variation of VMO/MMO with altitude or 
compressibility limitations (as appropriate), or a radial red line 
marking for VMO/MMO must be made at lowest value 
of VMO/MMO established for any altitude up to the 
maximum operating altitude for the airplane.

0
56. Amend Sec.  23.1555 by adding a new paragraph (d)(3) to read as 
follows:

Sec.  23.1555  Control markings.

* * * * *
    (d) * * *
    (3) For fuel systems having a calibrated fuel quantity indication 
system complying with Sec.  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.
* * * * *

0
57. Amend Sec.  23.1559 by adding a new paragraph (d) to read as 
follows:

Sec.  23.1559  Operating limitations placard.

* * * * *
    (d) The placard(s) required by this section need not be lighted.

0
58. Amend Sec.  23.1563 by adding a new paragraph (d) to read as 
follows:

Sec.  23.1563  Airspeed placard.

* * * * *
    (d) The airspeed placard(s) required by this section need not be 
lighted if the landing gear operating speed is indicated on the 
airspeed indicator or other lighted area such as the landing gear 
control and the airspeed indicator has features such as low speed 
awareness that provide ample warning prior to VMC.

0
59. Amend Sec.  23.1567 by adding a new paragraph (e) to read as 
follows:

Sec.  23.1567  Flight maneuver placard.

* * * * *
    (e) The placard(s) required by this section need not be lighted.

0
60. Amend Sec.  23.1583 as follows:
0
A. Revise the introductory text of paragraphs (c)(3) and (c)(4);
0
B. Redesignate paragraphs (c)(4)(iii) and (c)(4)(iv) as paragraphs 
(c)(4)(ii)(A) and (c)(4)(ii)(B); and
0
C. Revise paragraph (c)(5) introductory text:

Sec.  23.1583  Operating limitations.

* * * * *
    (c) * * *
    (3) For reciprocating engine-powered airplanes of more than 6,000 
pounds maximum weight, single-engine turbines, and multiengine jets 
6,000 pounds or less maximum weight in the normal, utility, and 
acrobatic category, performance operating limitations as follows--
* * * * *
    (4) For normal, utility, and acrobatic category multiengine jets 
over 6,000 pounds and commuter category airplanes, the maximum takeoff 
weight for each airport altitude and ambient temperature within the 
range selected by the applicant at which--
* * * * *
    (5) For normal, utility, and acrobatic category multiengine jets 
over 6,000 pounds and commuter category airplanes, the maximum landing 
weight for each airport altitude within the range selected by the 
applicant at which--
* * * * *
0
61. Amend Sec.  23.1585 by revising paragraph (f) introductory text to 
read as follows:

Sec.  23.1585  Operating procedures.

* * * * *
    (f) In addition to paragraphs (a) and (c) of this section, for 
normal, utility, and acrobatic category multiengine jets weighing over 
6,000 pounds, and commuter category airplanes, the information must 
include the following:
* * * * *

0
62. Amend Sec.  23.1587 by revising paragraph (d) introductory text to 
read as follows:

Sec.  23.1587  Performance information.

* * * * *
    (d) In addition to paragraph (a) of this section, for normal, 
utility, and acrobatic category multiengine jets weighing over 6,000 
pounds, and commuter category airplanes, the following information must 
be furnished--
* * * * *

0
63. Amend Appendix F to Part 23 as follows:
0
A. Redesignate the existing text as Part I and add a new Part I 
heading;
0
B. Add a new Part II.

Appendix F to Part 23--Test Procedure

Part I--Acceptable Test Procedure for Self-Extinguishing Materials for 
Showing Compliance With Sec. Sec.  23.853, 23.855, and 23.1359

* * * * *

Part II--Test Method To Determine the Flammability and Flame 
Propagation Characteristics of Thermal/Acoustic Insulation Materials

    Use this test method to evaluate the flammability and flame 
propagation characteristics of thermal/acoustic insulation when 
exposed to both a radiant heat source and a flame.
    (a) Definitions.
    Flame propagation means the furthest distance of the propagation 
of visible flame towards the far end of the test specimen, measured 
from the midpoint of the ignition source flame. Measure this 
distance after initially applying the ignition source and before all 
flame on the test specimen is extinguished. The measurement is not a 
determination of burn length made after the test.
    Radiant heat source means an electric or air propane panel.
    Thermal/acoustic insulation means a material or system of 
materials used to provide thermal and/or acoustic protection. 
Examples include fiberglass or other batting material encapsulated 
by a film covering and foams.
    Zero point means the point of application of the pilot burner to 
the test specimen.
    (b) Test apparatus.
BILLING CODE 4910-13-P

[[Page 75764]]

[GRAPHIC] [TIFF OMITTED] TR02DE11.087

    (1) Radiant panel test chamber. Conduct tests in a radiant panel 
test chamber (see figure F1 above). Place the test chamber under an 
exhaust hood to facilitate clearing the chamber of smoke after each 
test. The radiant panel test chamber must be an enclosure 55 inches 
(1397 mm) long by 19.5 inches (495 mm) deep by 28 inches (710 mm) to 
30 inches (maximum) (762 mm) above the test specimen. Insulate the 
sides, ends, and top with a fibrous ceramic insulation, such as 
Kaowool MTM board. On the front side, provide a 52 by 12-inch (1321 
by 305 mm) draft-free, high-temperature, glass window for viewing 
the sample during testing. Place a door below the window to provide 
access to the movable specimen platform holder. The bottom of the 
test chamber must be a sliding steel platform that has provision for 
securing the test specimen holder in a fixed and level position. The 
chamber must have an internal chimney with exterior dimensions of 
5.1 inches (129 mm) wide, by 16.2 inches (411 mm) deep by 13 inches 
(330 mm) high at the opposite end of the chamber from the radiant 
energy source. The interior dimensions must be 4.5 inches (114 mm) 
wide by 15.6 inches (395 mm) deep. The chimney must extend to the 
top of the chamber (see figure F2).
[GRAPHIC] [TIFF OMITTED] TR02DE11.088

    (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 [deg]F (704 [deg]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 
[deg]F (816 [deg]C). See figures F3a and F3b.

[[Page 75765]]

[GRAPHIC] [TIFF OMITTED] TR02DE11.089

BILLING CODE 4910-13-C
    (i) Electric radiant panel. The radiant panel must be 3-phase 
and operate at 208 volts. A single-phase, 240 volt panel is also 
acceptable. Use a solid-state power controller and microprocessor-
based controller to set the electric panel operating parameters.
    (ii) Gas radiant panel. Use propane (liquid petroleum gas--2.1 
UN 1075) for the radiant panel fuel. The panel fuel system must 
consist of a venturi-type aspirator for mixing gas and air at 
approximately atmospheric pressure. Provide suitable instrumentation 
for monitoring and controlling the flow of fuel and air to the 
panel. Include an air flow gauge, an air flow regulator, and a gas 
pressure gauge.
    (iii) Radiant panel placement. Mount the panel in the chamber at 
30 degrees to the horizontal specimen plane, and 7\1/2\ 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 non-

[[Page 75766]]

combustible sheets of material are available in \1/4\-inch (6 mm) 
thicknesses. See figure F4. A sliding platform that is deeper than 
the 2-inch (50.8mm) platform shown in figure F4 is also acceptable 
as long as the sample height requirement is met.
[GRAPHIC] [TIFF OMITTED] TR02DE11.090

    (ii) Attach a \1/2\-inch (13 mm) piece of Kaowool MTM board or 
other high temperature material measuring 41\1/2\ by 8\1/4\ inches 
(1054 by 210 mm) to the back of the platform. This board serves as a 
heat retainer and protects the test specimen from excessive 
preheating. The height of this board may not impede the sliding 
platform movement (in and out of the test chamber). If the platform 
has been fabricated such that the back side of the platform is high 
enough to prevent excess preheating of the specimen when the sliding 
platform is out, a retainer board is not necessary.
    (iii) Place the test specimen horizontally on the non-
combustible board(s). Place a steel retaining/securing frame 
fabricated of mild steel, having a thickness of \1/8\-inch (3.2 mm) 
and overall dimensions of 23 by 13\1/8\ inches (584 by 333 mm) with 
a specimen opening of 19 by 10\3/4\ 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.

[[Page 75767]]

[GRAPHIC] [TIFF OMITTED] TR02DE11.091

    (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 2\7/8\ 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.
[GRAPHIC] [TIFF OMITTED] TR02DE11.092

    (5) Thermocouples. Install a 24 American Wire Gauge (AWG) Type K 
(Chromel- Alumel) 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, 
11\1/2\ inches (292 mm) from the right side of the chamber wall, and 
is 2 inches (51 mm) below the radiant panel. The use of other 
thermocouples is optional.
    (6) Calorimeter. The calorimeter must be a one-inch cylindrical 
water-cooled, total heat flux density, foil type Gardon Gage that 
has a range of 0 to 5 BTU/ft \2\-second (0 to 5.7 Watts/cm \2\).
    (7) Calorimeter calibration specification and procedure.
    (i) Calorimeter specification.
    (A) Foil diameter must be 0.25 +/-0.005 inches (6.35 +/-0.13 
mm).
    (B) Foil thickness must be 0.0005 +/-0.0001 inches (0.013 +/- 
0.0025 mm).
    (C) Foil material must be thermocouple grade Constantan.
    (D) Temperature measurement must be a Copper Constantan 
thermocouple.
    (E) The copper center wire diameter must be 0.0005 inches (0.013 
mm).
    (F) The entire face of the calorimeter must be lightly coated 
with ``Black Velvet'' paint having an emissivity of 96 or greater.
    (ii) Calorimeter calibration.
    (A) The calibration method must be by comparison to a like 
standardized transducer.

[[Page 75768]]

    (B) The standardized transducer must meet the specifications 
given in paragraph II(b)(6) of this appendix.
    (C) Calibrate the standard transducer against a primary standard 
traceable to the National Institute of Standards and Technology 
(NIST).
    (D) The method of transfer must be a heated graphite plate.
    (E) The graphite plate must be electrically heated, have a clear 
surface area on each side of the plate of at least 2 by 2 inches (51 
by 51 mm), and be \1/8\-inch +/- \1/16\-inch thick (3.2 +/- 1.6 mm).
    (F) Center the 2 transducers on opposite sides of the plates at 
equal distances from the plate.
    (G) The distance of the calorimeter to the plate must be no less 
than 0.0625 inches (1.6 mm), and no greater than 0.375 inches (9.5 
mm).
    (H) The range used in calibration must be at least 0-3.5 BTUs/ft 
\2\-second (0-3.9 Watts/cm \2\) and no greater than 0-5.7 BTUs/ft 
\2\-second (0-6.4 Watts/cm \2\).
    (I) The recording device used must record the 2 transducers 
simultaneously or at least within \1/10\ of each other.
    (8) Calorimeter fixture. With the sliding platform pulled out of 
the chamber, install the calorimeter holding frame and place a sheet 
of non-combustible material in the bottom of the sliding platform 
adjacent to the holding frame. This will prevent heat losses during 
calibration. The frame must be 13\1/8\ 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 7\1/2\  \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.
[GRAPHIC] [TIFF OMITTED] TR02DE11.093

    (9) Instrumentation. Provide a calibrated recording device with 
an appropriate range or a computerized data acquisition system to 
measure and record the outputs of the calorimeter and the 
thermocouple. The data acquisition system must be capable of 
recording the calorimeter output every second during calibration.
    (10) Timing device. Provide a stopwatch or other device, 
accurate to  1 second/hour, to measure the time of 
application of the pilot burner flame.
    (c) Test specimens.
    (1) Specimen preparation. Prepare and test a minimum of three 
test specimens. If an oriented film cover material is used, prepare 
and test both the warp and fill directions.
    (2) Construction. Test specimens must include all materials used 
in construction of the insulation (including batting, film, scrim, 
tape, etc.). Cut a piece of core material such as foam or 
fiberglass, and cut a piece of film cover material (if used) large 
enough to cover the core material. Heat sealing is the preferred 
method of preparing fiberglass samples, since they can be made 
without compressing the fiberglass (``box sample''). Cover materials 
that are not heat sealable may be stapled, sewn, or taped as long as 
the cover material is sufficiently over-cut to be drawn down the 
sides without compressing the core material. The fastening means 
should be as continuous as possible along the length of the seams. 
The specimen thickness must be of the same thickness as installed in 
the airplane.
    (3) Specimen Dimensions. To facilitate proper placement of 
specimens in the sliding platform housing, cut non-rigid core 
materials, such as fiberglass, 12\1/2\ inches (318mm) wide by 23 
inches (584mm) long. Cut rigid materials, such as foam, 11\1/2\ 
 \1/4\ inches (292 mm  6mm) wide by 23 
inches (584mm) long in order to fit properly in the sliding platform 
housing and provide a flat, exposed surface equal to the opening in 
the housing.
    (d) Specimen conditioning. Condition the test specimens at 70 
 5 [deg]F (21  2 [deg]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 7\1/2\ 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/feet\2\-second  5 percent (1.7 Watts/cm\2\  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.

[[Page 75769]]

                       Table 1--Calibration Table
------------------------------------------------------------------------
           Position               BTU/feet\ 2\ sec       Watts/cm\2\
------------------------------------------------------------------------
``Zero'' Position.............                 1.5                  1.7
Position 1....................      1.51-1.50-1.49       1.71-1.70-1.69
Position 2....................           1.43-1.44            1.62-1.63
------------------------------------------------------------------------

     (4) Open the bottom door, remove the calorimeter and holder 
fixture. Use caution as the fixture is very hot.
    (f) Test Procedure.
    (1) Ignite the pilot burner. Ensure that it is at least 2 inches 
(51 mm) above the top of the platform. The burner may not contact 
the specimen until the test begins.
    (2) Place the test specimen in the sliding platform holder. 
Ensure that the test sample surface is level with the top of the 
platform. At ``zero'' point, the specimen surface must be 7\1/2\ 
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 (7\1/2\ inches  \1/8\ inch (191 mm  3) at ``zero'' position). With film/fiberglass assemblies, it 
is critical to make a slit in the film cover to purge any air 
inside. This allows the operator to maintain the proper test 
specimen position (level with the top of the platform) and to allow 
ventilation of gases during testing. A longitudinal slit, 
approximately 2 inches (51mm) in length, must be centered 3 inches 
 \1/2\ inch (76mm  13mm) from the left 
flange of the securing frame. A utility knife is acceptable for 
slitting the film cover.
    (4) Immediately push the sliding platform into the chamber and 
close the bottom door.
    (5) Bring the pilot burner flame into contact with the center of 
the specimen at the ``zero'' point and simultaneously start the 
timer. The pilot burner must be at a 27 degree angle with the sample 
and be approximately \1/2\ inch (12 mm) above the sample. See figure 
F7. A stop, as shown in figure F8, allows the operator to position 
the burner correctly each time.
[GRAPHIC] [TIFF OMITTED] TR02DE11.094

    (6) Leave the burner in position for 15 seconds and then remove 
to a position at least 2 inches (51 mm) above the specimen.
    (g) Report.
    (1) Identify and describe the test specimen.
    (2) Report any shrinkage or melting of the test specimen.
    (3) Report the flame propagation distance. If this distance is 
less than 2 inches, report this as a pass (no measurement required).
    (4) Report the after-flame time.
    (h) Requirements.
    (1) There must be no flame propagation beyond 2 inches (51 mm) 
to the left of the centerline of the pilot flame application.
    (2) The flame time after removal of the pilot burner may not 
exceed 3 seconds on any specimen.

    Issued in Washington, DC, on November 16, 2011.
J. Randolph Babbitt,
Administrator.
[FR Doc. 2011-30412 Filed 12-1-11; 8:45 am]
BILLING CODE 4910-13-P