[Federal Register Volume 77, Number 7 (Wednesday, January 11, 2012)]
[Rules and Regulations]
[Pages 1614-1618]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-360]



Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2010-1193; Amdt. No. 25-136]
RIN 2120-AJ80

Harmonization of Airworthiness Standards for Transport Category 
Airplanes--Landing Gear Retracting Mechanisms and Pilot Compartment 

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.


SUMMARY: The Federal Aviation Administration amends the airworthiness 
standards for transport category airplanes on landing gear retracting 
mechanisms and the pilot compartment view. For the landing gear 
retracting mechanism, this rulemaking adopts the 1-g stall speed as a 
reference stall speed instead of the minimum speed obtained in a 
stalling maneuver and adds an additional requirement to keep the 
landing gear and doors in the correct retracted position in flight. For 
the pilot compartment view, this rulemaking revises the requirements 
for pilot compartment view in precipitation conditions. This action 
eliminates regulatory differences between the airworthiness standards 
of the U.S. and the European Aviation Safety Agency (EASA), without 
affecting current industry design practices.

DATES: Effective March 12, 2012.

ADDRESSES: For information on where to obtain copies of rulemaking 
documents and other information related to this final rule, see ``How 
To Obtain Additional Information'' in the SUPPLEMENTARY INFORMATION 
section of this document.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning 
this action, contact Mahinder Wahi, Federal Aviation Administration, 
Propulsion and Mechanical Systems Branch, ANM-112, Transport Airplane 
Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., 
Renton, WA 98057; telephone (425) 227-1262; facsimile (425) 227-1320, 
email mahinder.wahi@faa.gov.
    For legal questions about this proposed rule, contact Doug 
Anderson, FAA, Office of the Regional Counsel (ANM-7), 1601 Lind Avenue 
SW., Renton, Washington 98057; telephone (425) 227-2166; facsimile 
(425) 227-1007; email Douglas.Anderson@faa.gov.


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, ``General 
requirements.'' Under that section, the FAA is charged with promoting 
safe flight of civil aircraft in air commerce by prescribing 
regulations and minimum standards for the design and performance of 
aircraft that the Administrator finds necessary for safety in air 
commerce. This regulation is within the scope of that authority. It 
prescribes new safety standards for the design and operation of 
transport category airplanes.

List of Abbreviations Frequently Used in This Document

Term Definition
VS the stalling speed or the minimum steady flight speed 
at which the airplane is controllable.
VS1 the stalling speed or the minimum steady flight speed 
obtained in a specific configuration.
VSR reference stall speed and may not be less than a 1-g 
stall speed.
VSR1 reference stall speed in a specific configuration.
1-g stall speed minimum speed at which the airplane can develop the 
usable maximum lift force capable of supporting the weight of the 

List of Acronyms Frequently Used in This Document

ALPA Airline Pilots Association
ANAC Ag[ecirc]ncia Nacional de Avia[ccedil][atilde]o Civil
ARAC Aviation Rulemaking Advisory Committee
EASA European Aviation Safety Agency
FAA Federal Aviation Administration
ICAO International Civil Aviation Organization
JAA European Joint Aviation Authorities
NPRM Notice of Proposed Rulemaking
RFA Regulatory Flexibility Act
SBREFA Small Business Regulatory Enforcement Fairness Act

I. Overview of Final Rule

    This action harmonizes airworthiness certification standards for 
landing gear mechanisms and pilot compartment view for transport 
category airplanes with those of EASA. Harmonizing these airworthiness 
standards reduces costs to airplane manufacturers and operators while 
retaining the level of safety.

II. Background

A. Statement of the Problem

    This rulemaking results from an agreement between the European 
Joint Aviation Authorities (JAA), the predecessor to EASA, and the FAA 
to harmonize certain airworthiness standards between the two 
authorities. Differences between the regulations of the FAA and foreign 
certification authorities increase the cost and complexity of 
certification without contributing significantly to safety. These rules 
result from the recommendations of the Aviation Rulemaking Advisory 
Committee, through its Mechanical Systems Harmonization Working Group 

B. Summary of the NPRM

    The FAA published a notice of proposed rulemaking (NPRM), Docket 
No. FAA-2010-1193; Notice No. 10-19 in the Federal Register on January 
5, 2011 (76 FR 472). The NPRM proposed to amend the standards for 
landing gear retraction mechanism and pilot compartment view to 
harmonize with the corresponding EASA standards. The proposed standards 
for landing gear addressed reference stall speed, positive means to 
keep the landing gear and doors in the correct retracted position, gear 
position indication, and protection of equipment on the landing gear 
and in the wheel well. The proposed standards for pilot compartment 
view addressed single failures of rain removal systems, alternatives to 
the openable side window requirement and certain environmental 
    The comment period for the NPRM ended on April 5, 2011.

C. General Overview of Comments

    The FAA received comments from Airbus, Boeing Company, Bombardier, 
Cessna Aircraft Company, Embraer,

[[Page 1615]]

Hawker Beechcraft, Transport Canada, and Air Line Pilots Association, 
International (ALPA). ALPA, Airbus, Bombardier, and Cessna provided 
general comments in support of the proposed changes.
    Embraer correctly noted that a proposed text change to Sec.  
25.729(a)(3) was unnecessary since EASA had already adopted the current 
FAA standard. The proposed change to Sec.  25.729(a)(3) is therefore 
withdrawn. Boeing, Transport Canada, and Hawker Beechcraft proposed 
changes to the regulatory text. Embraer requested that the FAA wait for 
the final rule issuance of NPRM 10-10, Airplane and Engine 
Certification Requirements in Supercooled Large Drop, Mixed Phase, and 
Ice Crystal Icing Conditions (75 FR 37311, June 29, 2010) (Docket No. 
FAA-2010-0636) before issuing this final rule. Boeing, Transport Canada 
and Bombardier noted editorial errors which have been corrected.

D. Associated Advisory Circular Guidance Material

    Advisory Circular AC 25.729-1 has been revised to incorporate 
acceptable means of compliance to the amended requirements of this 
rulemaking action. A draft of this AC was made available for public 
comment during the comment period of the NPRM. The FAA received 
comments on the AC from the Brazilian Civil Aviation Authority 
(Ag[ecirc]ncia Nacional de Avia[ccedil][atilde]o Civil--ANAC), 
Transport Canada, Boeing Company, and Embraer. The disposition of the 
AC public comments is posted along with the final version of the AC on 
the FAA Regulatory and Guidance Library Web site (http://rgl.faa.gov/).

III. Discussion of Public Comments and Final Rule

A. Effect of Flightcrew Alerting Rule

    Boeing recommended the proposed rule for landing gear position 
indication be revised to be consistent with the new flightcrew alerting 
rule, Sec.  25.1322. Boeing's rationale is that the proposed wording of 
Sec.  25.729(e) in the NPRM is inconsistent with retractable landing 
gear and associated door indication systems on existing FAA type 
certificated and recent EASA validated airplanes. Boeing also stated 
the proposed wording and the associated AC guidance material are 
inconsistent with the quiet and dark flight deck philosophy used on 
modern airplanes.
    The proposed wording would have required ``a clear indication or 
warning must be provided whenever the landing gear position is not 
consistent with the landing gear selector lever position.'' In some 
situations, an advisory or caution message would be appropriate, not a 
warning message. Boeing requested a change to make warning, caution, 
and advisory messages compliant with Sec.  25.1322 and provide 
information to the flight crew if the gear or doors are not in the 
commanded position or are in a hazardous configuration. Boeing also 
recommended deleting Sec.  25.729(e)(7) and rewording paragraph (e) to 
reference Sec.  25.1322 for alerting.
    We agree the specification to provide a ``warning'' as in the 
proposed Sec.  25.729(e)(7) is not consistent with the Sec.  25.1322 at 
the current amendment level. ARAC recommended and EASA adopted the 
proposed wording prior to the development of the current Sec.  25.1322 
requirements. The intent of the wording recommended by ARAC was 
consistent with the definition of the term ``flightcrew alert'' in the 
current Sec.  25.1322. We replaced the wording ``clear indication or 
warning'' with ``flightcrew alert'' to be consistent with Sec.  
25.1322. This also addresses the Boeing comment associated with the 
quiet and dark flightdeck concept. It is not necessary to specifically 
refer to Sec.  25.1322 in the rule text, as the current version of 
Sec.  25.1322 will be in the certification basis for new type designs 
and new significant changes to type design (as determined per 14 CFR 
Sec.  21.101).
    Boeing also noted the regulation does not address other landing 
gear actuation functions, such as a landing gear lever lock or truck 
tilt message to prevent retraction or the hazards associated with 
retracting an out of configuration gear, or the necessary indication 
for hazards associated with semi-lever gears or tail skid actuation.
    The FAA considers that Sec. Sec.  25.1301, 25.1309 and 25.1322 
adequately address identification and alerting of these hazards and 
provide the applicant the greatest flexibility in the use of such 
functions. No change to the rule will be made in this regard.

B. Wheel Brake Temperature

    Hawker Beechcraft stated the proposed wording for Sec.  
25.729(f)(3), ``possible wheel brake temperatures,'' is not specific 
enough. Hawker Beechcraft recommends changing the text to ``excessive 
wheel brake temperatures,'' or ``wheel brakes overheating.'' We note 
that because Sec.  25.729(f) refers to the ``damaging effects of'' the 
temperatures, we believe it is clear the regulation refers to high 
``possible'' temperatures. No changes were made to the rule in response 
to this comment.

C. Landing Gear Lock

    Transport Canada concurs with the new requirement for a positive 
means to keep the landing gear and doors in the correct retracted 
position in flight, and would like a similar requirement for a 
downlock. As proposed, Sec.  25.729(b) is a performance-based rule that 
requires positive means to keep the landing gear extended in flight and 
on the ground. Adding specificity to require a downlock, limits design 
options that would otherwise meet the intent of the rule without 
increasing the level of safety. No change to the rule was made in this 

D. Supercooled Large Drop Rulemaking

    Embraer suggested the FAA publish the final rule associated with 
NPRM Notice No. 10-10, previously referenced on page 5, before 
proceeding with proposed changes to Sec.  25.773(b) in this rulemaking 
since the NPRM proposed to change Sec.  25.773(b)(1). This rulemaking 
includes changes to Sec.  25.773(b)(2) and additionally to Sec.  
25.773(b)(3) and (4), but proposed no changes to Sec.  25.773(b)(1). 
Since these rulemaking changes are independent of those proposed in the 
Supercooled Large Drop NPRM, the FAA does not plan to wait on 
publishing this rule.

E. Lightning as a Discrete Damage Source for Pilot Compartment View

    Transport Canada requested we add lightning to the list of discrete 
damage sources presented in Sec.  25.773(b)(4)(ii). The FAA is not 
aware of any data that indicates lightning has resulted in the 
reduction of pilot compartment view, therefore changing the regulatory 
text is unnecessary.

F. Differences Between the NPRM and the Final Rule

    Except for the editorial correction in the rule title for Sec.  
25.729, the withdrawal of proposed text change to Sec.  25.729(a)(3), 
and the change in amendatory language found in Sec.  25.729(e)(7) from 
``A clear indication or warning'' to ``A flightcrew alert,'' the 
changes to Sec. Sec.  25.729 and 25.773 are adopted as proposed.

IV. Regulatory Notices and Analyses

A. Regulatory Evaluation

    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Order 12866 and Executive Order 13563 direct 
that each Federal agency shall propose or adopt a regulation only upon 
a reasoned determination that the benefits of the intended regulation 
justify its costs. Second, the Regulatory Flexibility Act

[[Page 1616]]

of 1980 (Pub. L. 96-354) requires agencies to analyze the economic 
impact of regulatory changes on small entities. Third, the Trade 
Agreements Act (Pub. L. 96-39) prohibits agencies from setting 
standards that create unnecessary obstacles to the foreign commerce of 
the United States. In developing U.S. standards, this Trade Act 
requires agencies to consider international standards and, where 
appropriate, that they be the basis of U.S. standards. Fourth, the 
Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4) requires agencies 
to prepare a written assessment of the costs, benefits, and other 
effects of proposed or final rules that include a Federal mandate 
likely to result in the expenditure by State, local, or tribal 
governments, in the aggregate, or by the private sector, of $100 
million or more annually (adjusted for inflation with base year of 
1995). This portion of the preamble summarizes the FAA's analysis of 
the economic impact of the final rule.
    Department of Transportation Order DOT 2100.5 prescribes policies 
and procedures for simplification, analysis, and review of regulations. 
If the expected cost impact is so minimal that a proposed or final rule 
does not warrant a full evaluation, this order permits that a statement 
to that effect and the basis for it be included in the preamble if a 
full regulatory evaluation of the costs and benefits is not prepared. 
Such a determination has been made for this final rule.
    The reasoning for this determination follows: The final rule will 
amend the airworthiness standards for transport category airplanes for 
landing gear retracting mechanisms and pilot compartment view to 
harmonize with existing, more stringent European Aviation Safety Agency 
(EASA) requirements. For landing gear retracting mechanisms, the more 
stringent EASA requirements ensure (1) The landing gear is in the 
appropriate configuration; (2) the landing gear and its supporting 
structure, doors, and mechanisms operate properly; (3) the flight crew 
is aware of the landing gear position status; and (4) critical 
equipment is protected from tire failure or excessive brake 
    For the pilot compartment view, reliable and safe operation during 
precipitation is ensured by adoption of the EASA design requirements 
for flight deck rain removal systems because there will be no single 
failure of the rain removal system that could lead to a loss of pilot 
view through both windshields. The effect of this requirement is that, 
for newly certificated airplanes, manufacturers must provide a 
separate, mechanically and electrically independent method for clearing 
the windshield during precipitation. This method may include separate 
flight deck control switches for left and right windshield wipers. The 
FAA has determined that installation of the second wiper switch will 
require minimal additional costs when the system is initially designed 
to comply with the EASA requirement and received no comments regarding 
this estimate.
    A review of current practices of U.S. manufacturers of transport 
category airplanes has revealed that only a minority of manufacturers 
are not already in compliance with the EASA requirements. For these 
manufacturers, the FAA has determined that additional costs to comply 
with the EASA requirements will be minimal and that there will be 
additional safety benefits from adoption of the more stringent EASA 
requirements. For the majority of manufacturers already in compliance 
with the EASA requirements as a means of obtaining joint certification, 
there will be no additional compliance costs or additional safety 
benefits. We received no comments regarding this cost estimate. 
However, the final rule will provide benefits from reduced joint 
certification costs--in the requirements for data collection and 
analysis, paperwork, and time spent applying for and obtaining approval 
from the regulatory authorities. The FAA therefore has determined that 
this final rule will have minimal costs and positive net benefits and 
does not warrant a full regulatory evaluation.
    The FAA has also determined that this final rule is not a 
``significant regulatory action'' as defined in section 3(f) of 
Executive Order 12866, and is not ``significant'' as defined in DOT's 
Regulatory Policies and Procedures.

B. 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 would, 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.
    As noted above, this final rule will impose no or little additional 
costs on part 25 manufacturers. Moreover, all U.S. manufacturers of 
transport category airplanes exceed the Small Business Administration 
small-entity criteria of 1,500 employees. Therefore, the FAA certifies 
that this final rule will not have a significant economic impact on a 
substantial number of small entities.

C. International Trade Impact Assessment

    The Trade Agreements Act of 1979 (Pub. L. 96-39), as amended by the 
Uruguay Round Agreements Act (Pub. L. 103-465), prohibits Federal 
agencies from establishing standards or engaging in related activities 
that create unnecessary obstacles to the foreign commerce of the United 
States. Pursuant to these Acts, the establishment of standards is not 
considered an unnecessary obstacle to the foreign commerce of the 
United States, so long as the standard has a legitimate domestic 
objective, such 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 it 
will promote international trade by harmonizing U.S. standards with 
corresponding EASA regulations thus reducing the cost of joint 

D. Unfunded Mandates Assessment

    Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires each Federal agency to prepare a written statement 
assessing the effects of any Federal mandate in a proposed or final 
agency rule that may result in an expenditure of $100 million or more 
(adjusted annually for inflation with the base year 1995) in any one 
year by State,

[[Page 1617]]

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 $141.3 
    This final rule does not contain such a mandate. The requirements 
of Title II do not apply.

E. Paperwork Reduction Act

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

F. 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 
determined that there are no ICAO Standards and Recommended Practices 
that correspond to these regulations.

G. 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 312d and involves no extraordinary 

H. 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, the 
FAA requested comments on whether the proposed rule should apply 
differently to intrastate operations in Alaska. The agency did not 
receive any comments, and has 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.

V. Executive Order Determinations

A. Executive Order 13132, Federalism

    The FAA has analyzed this final rule under the principles and 
criteria of Executive Order 13132, Federalism. The agency 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, and, therefore, does not have Federalism 

B. Executive Order 13211, 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). The agency has determined that it 
is not a ``significant energy action'' under the executive order and it 
is not likely to have a significant adverse effect on the supply, 
distribution, or use of energy.

VI. How To Obtain Additional Information

A. Rulemaking Documents

    An electronic copy of a rulemaking document may be obtained by 
using the Internet:
    1. Search the Federal eRulemaking Portal (http://www.regulations.gov);
    2. Visit the FAA's Regulations and Policies Web page at http://www.faa.gov/regulations_policies/ or
    3. Access the Government Printing Office's Web page at http://www.fdsys.gov.
    Copies may also be obtained by sending a request (identified by 
notice, amendment, or docket number of this rulemaking) to the Federal 
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence 
Avenue SW., Washington, DC 20591, or by calling (202) 267-9680.

B. Comments Submitted to the Docket

    Comments received may be viewed by going to http://www.regulations.gov and following the online instructions to search the 
docket number for this action. Anyone is able to search the electronic 
form of all comments received into any of the FAA's dockets by the name 
of the individual submitting the comment (or signing the comment, if 
submitted on behalf of an association, business, labor union, etc.).

C. 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. A small entity with questions regarding this document, 
may contact its local FAA official, or the person listed under the FOR 
FURTHER INFORMATION CONTACT heading at the beginning of the preamble. 
To find out more about SBREFA on the Internet, visit http://www.faa.gov/regulations_policies/rulemaking/sbre_act/.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety.

The Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration amends part 25 of title 14, Code of Federal Regulations, 
as follows:


1. The authority citation for part 25 continues to read as follows:

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

2. Amend Sec.  25.729 by revising paragraphs (a)(1)(ii) and (iii), (b), 
(e) introductory text, and (e)(5), adding paragraph (e)(7), revising 
paragraphs (f) introductory text and (f)(1), and adding paragraph 
(f)(3) to read as follows:

Sec.  25.729  Retracting mechanism.

    (a) * * *
    (1) * * *
    (ii) The combination of friction loads, inertia loads, brake torque 
loads, air loads, and gyroscopic loads resulting from the wheels 
rotating at a peripheral speed equal to 1.23VSR (with the 
wing-flaps in take-off position at design take-off weight), occurring 
during retraction and extension at any airspeed up to 1.5 
VSR1 (with the wing-flaps in the approach position at design 
landing weight), and
    (iii) Any load factor up to those specified in Sec.  25.345(a) for 
the wing-flaps extended condition.
* * * * *
    (b) Landing gear lock. There must be positive means to keep the 
landing gear extended in flight and on the ground. There must be 
positive means to keep the landing gear and doors in the correct 
retracted position in flight, unless it can be shown that lowering of 
the landing gear or doors, or flight with the landing gear or doors 
extended, at any speed, is not hazardous.
* * * * *
    (e) Position indicator and warning device. If a retractable landing 
gear is

[[Page 1618]]

used, there must be a landing gear position indicator easily visible to 
the pilot or to the appropriate crew members (as well as necessary 
devices to actuate the indicator) to indicate without ambiguity that 
the retractable units and their associated doors are secured in the 
extended (or retracted) position. The means must be designed as 
* * * * *
    (5) The system used to generate the aural warning must be designed 
to minimize false or inappropriate alerts.
* * * * *
    (7) A flightcrew alert must be provided whenever the landing gear 
position is not consistent with the landing gear selector lever 
    (f) Protection of equipment on landing gear and in wheel wells. 
Equipment that is essential to the safe operation of the airplane and 
that is located on the landing gear and in wheel wells must be 
protected from the damaging effects of--
    (1) A bursting tire;
* * * * *
    (3) Possible wheel brake temperatures.

3. Amend Sec.  25.773 by revising paragraph (b)(2) and adding 
paragraphs (b)(3) and (4) to read as follows:

Sec.  25.773  Pilot compartment view.

* * * * *
    (b) * * *
    (2) No single failure of the systems used to provide the view 
required by paragraph (b)(1) of this section must cause the loss of 
that view by both pilots in the specified precipitation conditions.
    (3) The first pilot must have a window that--
    (i) Is openable under the conditions prescribed in paragraph (b)(1) 
of this section when the cabin is not pressurized;
    (ii) Provides the view specified in paragraph (b)(1) of this 
section; and
    (iii) Provides sufficient protection from the elements against 
impairment of the pilot's vision.
    (4) The openable window specified in paragraph (b)(3) of this 
section need not be provided if it is shown that an area of the 
transparent surface will remain clear sufficient for at least one pilot 
to land the airplane safely in the event of--
    (i) Any system failure or combination of failures which is not 
extremely improbable, in accordance with Sec.  25.1309, under the 
precipitation conditions specified in paragraph (b)(1) of this section.
    (ii) An encounter with severe hail, birds, or insects.
* * * * *

    Issued in Washington, DC, on December 27, 2011.
Michael P. Huerta,
Acting Administrator.
[FR Doc. 2012-360 Filed 1-10-12; 8:45 am]