Document ID: FAA-2019-0343-0001
Agency: faa
Document Type: Proposed Rule
Title: Decompression Criteria for Interior Compartments
Posted Date: 2019-05-15T04:00Z

[Federal Register Volume 84, Number 94 (Wednesday, May 15, 2019)]
[Proposed Rules]
[Pages 21733-21738]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-09823]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No.: FAA-2019-0343; Notice No. 19-04]
RIN 2120-AL11

Decompression Criteria for Interior Compartments

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to revise its standards for pressurized 
compartment loads such that partitions located immediately adjacent to 
a decompression hole need not be designed to withstand certain 
decompression conditions. This action is necessary because, in some 
cases, it is not practical to design partitions in certain airplane 
compartments to withstand a large decompression event that occurs 
within that compartment. Even though individual partition failure would 
be allowed, continued safe flight and landing would still be required.

DATES: Send comments on or before June 14, 2019.

ADDRESSES: Send comments identified by docket number FAA-2019-0343 
using any of the following methods:

[[Page 21734]]

     Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the online instructions for sending your 
comments electronically.
     Mail: Send comments to Docket Operations, M-30; U.S. 
Department of Transportation (DOT), 1200 New Jersey Avenue SE, Room 
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
     Hand Delivery or Courier: Take comments to Docket 
Operations in Room W12-140 of the West Building Ground Floor at 1200 
New Jersey Avenue SE, Washington, DC, between 9 a.m. and 5 p.m., Monday 
through Friday, except Federal holidays.
     Fax: Fax comments to Docket Operations at 202-493-2251.
    Privacy: In accordance with 5 U.S.C. 553(c), DOT solicits comments 
from the public to better inform its rulemaking process. DOT posts 
these comments, without edit, including any personal information the 
commenter provides, to www.regulations.gov, as described in the system 
of records notice (DOT/ALL-14 FDMS), which can be reviewed at 
www.dot.gov/privacy.
    Docket: Background documents or comments received may be read at 
http://www.regulations.gov at any time. Follow the online instructions 
for accessing the docket or go to the Docket Operations in Room W12-140 
of the West Building Ground Floor at 1200 New Jersey Avenue SE, 
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays.

FOR FURTHER INFORMATION CONTACT: For questions concerning this action, 
contact Todd Martin, Airframe and Cabin Safety Section, AIR-675, 
Transport Standards Branch, Policy and Innovation Division, Aircraft 
Certification Service, Federal Aviation Administration, 2200 South 
216th Street, Des Moines, WA 98198; telephone and fax (206) 231-3210; 
email Todd.Martin@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 issued 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 as it prescribes new 
safety standards for the design and performance of transport category 
airplanes.

I. Overview of Proposed Rule

    The FAA proposes to revise Sec.  25.365, ``Pressurized compartment 
loads,'' in Title 14, Code of Federal Regulations (14 CFR) Part 25, 
``Airworthiness Standards: Transport Category Airplanes.''
    The airworthiness standards in Sec.  25.365 address the safety 
effects of decompression. When the fuselage skin or another part of the 
pressurized boundary of an airplane fails for any reason, a 
decompression occurs if the cabin pressure is greater than the outside 
air pressure. When a decompression occurs, the pressurized air inside 
the airplane exits the hole, or opening, in the fuselage until 
equilibrium is reached. This can result in potentially high air loads 
on floors, partitions, and bulkheads.
    Section 25.365(e) addresses the structural integrity of the 
airplane by requiring that the airplane be capable of continued safe 
flight and landing following a sudden release of pressure through an 
opening in any compartment (i.e., a ``sudden decompression'').
    Section 25.365(g) requires applicants to design bulkheads, floors, 
and partitions, in pressurized compartments for occupants, to withstand 
the sudden decompression conditions specified in paragraph (e). Section 
25.365(g) also requires applicants to take reasonable design 
precautions to minimize the probability of parts becoming detached and 
injuring seated occupants.
    For certain smaller compartments on the airplane, such as 
lavatories, private suites, and crew rest areas, it may be difficult to 
achieve compliance with Sec.  25.365(g) because a large decompression 
hole, of the size specified in Sec.  25.365(e)(2), occurring in one of 
these compartments would result in very high air loads on the 
partitions that form the compartment. Thus, strengthening the 
partitions to sustain such high loads has been shown to be impractical 
in many cases for these smaller compartments because it could adversely 
affect the structural integrity of the aircraft and continued safe 
flight and landing. Further, alternative design strategies may impede 
the compartment's intended function.
    Therefore, due to the difficulty of safely designing partitions 
around small compartments to withstand the decompression without 
adversely affecting the safety of the airplane or the compartment's 
intended function, the FAA proposes to revise Sec.  25.365(g) to allow 
the failure of partitions that are immediately adjacent to the 
decompression hole. This allowance would only apply to the formula 
decompression hole specified in Sec.  25.365(e)(2). A hole of this size 
is typically the most severe decompression load design requirement for 
small compartments, such as lavatories, private suites, and crew rest 
areas. Finally, partition failure would only be allowed if (1) failure 
of the partition would not interfere with continued safe flight and 
landing, and (2) meeting the decompression condition in paragraph 
(e)(2) would be impractical.

II. Background

A. Statement of the Problem

    As previously noted, for compartments such as lavatories, private 
suites, and crew rest areas, compliance with the partition strength 
requirements of Sec.  25.365(g) may be difficult for applicants to 
achieve and could potentially reduce the safety of the airplane since 
the current regulation requires all partitions to withstand all 
decompression events. Therefore, designing compliant lavatories, 
private suites, and crew rest areas may not be practical unless the FAA 
grants relief, such as an exemption in accordance with 14 CFR part 11 
or an equivalent level of safety finding in accordance with 14 CFR 
21.21.

B. History

    Amendment 25-54 to Sec.  25.365, 45 FR 60154, September 11, 1980, 
introduced the requirement that bulkheads, floors, and partitions be 
designed to withstand the decompression conditions specified in the 
rule.
    In amendment 25-71 to Sec.  25.365, 55 FR 13474, April 10, 1990, 
the specific references to ``bulkheads, floors, and partitions'' were 
moved from paragraph (e) to paragraph (g) to stipulate the passenger 
protection criteria related to failure of these structures in occupied 
compartments, regardless of whether their failure could interfere with 
safe flight and landing.
    The current rule requires that the applicant consider partition 
failure in terms of the effects on occupant safety. However, in 
developing this requirement, the FAA recognized that structural 
integrity might not be maintained near the decompression hole. The 
preamble of the NPRM for amendment 25-71, 53 FR 8742, March 16, 1988, 
states, ``The loss of structural integrity at the opening location or

[[Page 21735]]

physiological effects on occupants are not considerations of the 
proposed rule,'' which indicates the FAA was aware of and accepted this 
risk to the occupant next to the opening location.
    The FAA has certified numerous airplanes for which the partition 
strength criteria in Sec.  25.365(e) at amendment 25-54 or Sec.  
25.365(g) at amendment 25-71 were included in the certification basis. 
Since the issuance of amendment 25-54, the FAA has found compliance on 
several projects to install small compartments on these airplanes based 
on a finding of equivalent level of safety (ELOS) to Sec.  25.365(e) at 
amendment 25-54 or Sec.  25.365(g) at amendment 25-71 (as applicable) 
in accordance with 14 CFR 21.21, the first of which was made in 
1989.\1\
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    \1\ An ELOS finding is made when the design does not comply with 
the applicable airworthiness provisions, but compensating factors, 
such as incorporating mitigating features (e.g., lanyards to 
restrain loose parts, and frangible structure to cause structural 
failure in a direction away from the seated occupant), provide an 
equivalent level of safety in accordance with 14 CFR 21.21(b)(1) for 
small compartment design. The FAA documents an ELOS finding in an 
ELOS memorandum that communicates to the public the rationale for 
the FAA's determination of equivalency to the level of safety 
intended by the regulations.
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    The FAA notes, however, that it has not consistently applied the 
rule and applicants have raised questions about the intent of the rule 
during recent certification programs.

III. Discussion of the Proposal

    Section 25.365 addresses the safety effects of decompression. When 
the fuselage skin or another part of the pressurized boundary of an 
airplane fails for any reason, a decompression occurs if the cabin 
pressure is greater than the outside air pressure. Decompressions can 
occur due to a number of causes, such as a fatigue failure, an engine 
rotor burst, or an explosive or incendiary device. When a decompression 
occurs, the pressurized air inside the airplane exits the hole, or 
opening, in the fuselage until equilibrium is reached. This can result 
in potentially high air loads on floors, partitions, and bulkheads. The 
magnitude of these forces depends on the size of the hole, its 
location, and the initial pressure differential between the cabin and 
the outside air.
    Section 25.365(e) requires structural integrity of the airplane 
following a sudden decompression. The rule specifies that the design be 
able to withstand the following sudden decompression conditions:
    Paragraph (e)(1)--penetration of any pressurized compartment by a 
portion of an engine following engine disintegration;
    Paragraph (e)(2)--an opening up to a ``formula'' size calculated 
from the diameter of the airplane's fuselage; and
    Paragraph (e)(3)--any other opening caused by failures not shown to 
be extremely improbable.
    Section 25.365(g) addresses occupant safety in that it requires 
applicants to design bulkheads, floors, and partitions, in pressurized 
compartments for occupants, to withstand the sudden decompression 
conditions specified in paragraph (e). Section 25.365(g) also requires 
applicants to take reasonable design precautions to minimize the 
probability of parts becoming detached and injuring seated occupants.
    For certain smaller compartments on the airplane, such as 
lavatories, private suites, and crew rest areas, it may be difficult to 
achieve compliance with Sec.  25.365(g) because a large decompression 
hole, of the size specified in Sec.  25.365(e)(2), occurring in one of 
these compartments would result in very high air loads on the 
partitions that form the compartment. Compliance is typically 
demonstrated by either: 1) Strengthening the partition to the extent 
that it would not fail, or 2) adding sufficient venting to reduce the 
loads on the partition, or some combination thereof. In some cases, 
both of these approaches have been shown to be impractical because the 
design cannot maintain the airplane's structural integrity or the 
partition's intended function, or a combination thereof. For example, 
strengthening the partition to the extent that it would not fail can 
actually increase the loads on the floor, thereby causing a potentially 
more serious floor failure, which could jeopardize continued safe 
flight either through structural failure or by damaging control systems 
routed through the floor. Adding venting would reduce loads on the 
partition, but in some cases, it is not possible to add enough venting 
and also maintain the intended purpose of the compartment. 
Additionally, if a large decompression hole occurs in one of these 
compartments, the risk to occupants of that compartment from the 
decompression itself is likely to be significant, and exceed any risk 
from the partition collapse.
    Therefore, due to the difficulty of safely designing partitions 
around small compartments to withstand the decompression without 
adversely affecting the safety of the airplane, the FAA proposes to 
revise Sec.  25.365(g) to allow the failure of partitions. This 
proposed change would not impact safety because it conforms the 
regulatory text to longstanding FAA practice established through 
equivalent level of safety findings and methods of compliance for small 
compartment design. This proposed change would also improve 
certification efficiency by eliminating the need for design-by-design 
equivalent level of safety analyses and findings to allow for such 
partition design. Accordingly, the FAA proposes to revise Sec.  
25.365(g) to state that partitions adjacent to the opening specified in 
paragraph (e)(2) need not be designed to withstand that condition if 
(1) failure of the partition would not interfere with continued safe 
flight and landing, and (2) meeting this decompression condition would 
be impractical.
    The proposed rule would only apply to partitions, meaning any non-
structural wall, non-structural floor, or non-structural ceiling panel, 
the failure of which would not compromise the structural integrity of 
the airplane. The term ``floor'' means a structural floor, such as a 
passenger or cargo floor that carries airplane structural loads. The 
floor of an overhead crew rest area, which is elevated above the main 
floor, would not be a structural floor because it does not carry 
airplane structural loads. This type of non-structural floor is a 
partition. The term ``bulkhead,'' as used in the proposed regulation, 
means a structural pressure bulkhead. The FAA considers a non-
structural, non-pressure bulkhead to be a partition because it does not 
carry airplane structural loads. The applicability of this rule is 
limited to partitions because the integrity of bulkheads and floors 
must be maintained to ensure continued safe flight and landing.
    The proposed rule would only allow failure of partitions for the 
decompression condition specified in Sec.  25.365(e)(2). This 
decompression condition, referred to as the ``formula'' hole size, is 
typically the most severe condition required by Sec.  25.365(e). 
Partition failure due to the other decompression conditions specified 
in Sec.  25.365(e) would continue to be prohibited because it is 
practical to design partitions to withstand those less significant 
decompression events.
    The exception provided in proposed Sec.  25.365(g)(2) only applies 
to the occupant safety provision of Sec.  25.365(g)(1). All partitions 
would still be required to meet the requirements in Sec.  25.365(e), 
which requires continued safe flight and landing. For example, if 
flight control cables run through a particular partition, and failure 
of that partition would cause a hazardous or catastrophic flight 
control system failure, then that partition would still be required to 
withstand all the

[[Page 21736]]

decompression conditions specified in Sec.  25.365(e).
    The proposed rule would also only allow failure of partitions for 
the ``formula hole'' decompression condition of paragraph (e)(2) if the 
applicant can show that withstanding that condition is impractical 
(i.e., there is no way to design the partitions to withstand the 
decompression condition of paragraph (e)(2) without adversely affecting 
safety or without affecting the functionality of the compartment). In 
some cases, depending on the particular partition configuration and the 
formula decompression hole size for the airplane, it may be practical 
to design all partitions to meet the decompression condition specified 
in paragraph (e)(2), regardless of their location. For example, the 
applicant may be able to add venting or make other changes to relieve 
the decompression loads on the partitions. Under the proposed rule, the 
applicant would only be allowed to design for partition failure if 
there is no practical way to design the partitions to withstand the 
decompression condition of paragraph (e)(2).
    For a compartment such as a lavatory, remote crew rest, or private 
suite, having a solid door is a fundamental feature for the intended 
use of the compartment. While using a curtain in place of a solid door 
would greatly improve the decompression capability of the compartment 
and is physically practical for the purpose of compliance with Sec.  
25.365(g), the FAA accepts that changing the door to a curtain in these 
instances would be impractical because the resulting design would not 
fulfill the purpose of the compartment.
    The second sentence of Sec.  25.365(g) requires that applicants 
take reasonable design precautions to minimize the probability of parts 
becoming detached and injuring occupants while in their seats. This 
proposal would not change that requirement. Therefore, in those cases 
where partitions are not required to withstand the decompression 
condition of Sec.  25.365(e)(2), the applicant must nevertheless take 
reasonable design precautions to minimize the probability that a failed 
partition will injure an occupant in the compartment. For example, the 
applicant can employ lanyards or other devices to reduce the chance 
that a failed partition will impact the occupant. The applicant, in 
this situation, must also add venting, as a reasonable design 
precaution, to the extent practical to reduce the chance the partition 
will fail as a result of smaller decompression hole sizes.

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 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, the Trade Act requires agencies to consider 
international standards and, where appropriate, that they be the basis 
of U.S. standards. Fourth, the Unfunded Mandates Reform Act of 1995 
(Pub. L. 104-4) requires agencies to prepare a written assessment of 
the costs, benefits, and other effects of proposed or final rules that 
include a Federal mandate likely to result in the expenditure by State, 
local, or tribal governments, in the aggregate, or by the private 
sector, of $100 million or more annually (adjusted for inflation with 
base year of 1995). This portion of the preamble summarizes the FAA's 
analysis of the economic impacts of this proposed rule.
    This proposed rule would codify current practice and would not 
result in additional costs or significant benefits to airplane 
manufacturers. As noted previously, in some cases, the FAA accepted the 
possibility of local partition failure based on a finding of equivalent 
level of safety. This proposed rule would relieve type certification 
applicants who might otherwise be required to submit requests for an 
equivalent level of safety under Sec.  21.21(b)(1). However, cost 
savings for the FAA would be minimal because the FAA received only two 
such type certification applications in the past 5 years, and would not 
expect numerous similar applications in the future. Cost savings for 
industry would be minimal because the cost of administration of the 
FAA's finding of equivalent safety on each applicable certification 
project is not high, even though it is applied several times per year. 
The FAA, therefore, has determined that this proposed rule is not a 
``significant regulatory action'' as defined in section 3(f) of 
Executive Order 12866.

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 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.
    This proposed rule would only have impact on transport category 
airplanes. All United States transport category aircraft manufacturers 
exceed the Small Business Administration small-entity criteria of 1,500 
employees.
    If an agency determines that a rulemaking will not result in a 
significant economic impact on a substantial number of small entities, 
the head of the agency may so certify under section 605(b) of the RFA. 
Therefore, based on the foregoing analysis, as provided in section 
605(b), the head of the FAA certifies that this rulemaking will not 
result in 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

[[Page 21737]]

the foreign commerce of the United States, so long as the standard has 
a legitimate domestic objective, such as the protection of safety, and 
does not operate in a manner that excludes imports that meet this 
objective. The statute also requires consideration of international 
standards and, where appropriate, that they be the basis for U.S. 
standards. The FAA has assessed the potential effect of this proposed 
rule and determined that it would impose no costs on domestic and 
international entities and thus has a neutral trade impact.

D. Unfunded Mandates Assessment

    Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires each Federal agency to prepare a written statement 
assessing the effects of any Federal mandate in a proposed or final 
agency rule that may result in an expenditure of $100 million or more 
(in 1995 dollars) in any one year by State, local, and tribal 
governments, in the aggregate, or by the private sector; such a mandate 
is deemed to be a ``significant regulatory action.'' The FAA currently 
uses an inflation-adjusted value of $155 million in lieu of $100 
million. This proposed rule does not contain such a mandate; therefore, 
the requirements of Title II of the Act do not apply.

E. Paperwork Reduction Act

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

G. Environmental Analysis

    FAA Order 1050.1F identifies FAA actions that are categorically 
excluded from preparation of an environmental assessment or 
environmental impact statement under the National Environmental Policy 
Act in the absence of extraordinary circumstances. The FAA has 
determined this rulemaking action qualifies for the categorical 
exclusion identified in paragraph 5-6.6 of FAA Order 1050.1F and 
involves no extraordinary circumstances.

V. Executive Order Determinations

A. Executive Order 13132, Federalism

    The FAA has analyzed this proposed rule under the principles and 
criteria of Executive Order 13132, ``Federalism.'' The agency has 
determined that this action would not have a substantial direct effect 
on the States, or the relationship between the Federal Government and 
the States, or on the distribution of power and responsibilities among 
the various levels of government, and, therefore, would not have 
Federalism implications.

B. Executive Order 13211, Regulations That Significantly Affect Energy 
Supply, Distribution, or Use

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

C. Executive Order 13609, International Cooperation

    Executive Order 13609, ``Promoting International Regulatory 
Cooperation,'' promotes international regulatory cooperation to meet 
shared challenges involving health, safety, labor, security, 
environmental, and other issues and to reduce, eliminate, or prevent 
unnecessary differences in regulatory requirements. The FAA has 
analyzed this action under the policies and agency responsibilities of 
Executive Order 13609, and has determined that this action would have 
no effect on international regulatory cooperation.

D. Executive Order 13771, Reducing Regulation and Controlling 
Regulatory Costs

    This proposed rule is an Executive Order 13771 deregulatory action. 
Details on the regulatory relief provided by this proposed rule can be 
found in the Regulatory Evaluation section.

VI. Additional Information

E. Comments Invited

    The FAA invites interested persons to participate in this 
rulemaking by submitting written comments, data, or views. The agency 
also invites comments relating to the economic, environmental, energy, 
or federalism impacts that might result from adopting the proposals in 
this document. The most helpful comments reference a specific portion 
of the proposal, explain the reason for any recommended change, and 
include supporting data. To ensure the docket does not contain 
duplicate comments, commenters should send only one copy of written 
comments, or if comments are filed electronically, commenters should 
submit only one time.
    The FAA will file in the docket all comments it receives, as well 
as a report summarizing each substantive public contact with FAA 
personnel concerning this proposed rulemaking. Before acting on this 
proposal, the FAA will consider all comments it receives on or before 
the closing date for comments. The FAA will consider comments filed 
after the comment period has closed if it is possible to do so without 
incurring expense or delay. The agency may change this proposal in 
light of the comments it receives.
    Proprietary or Confidential Business Information: Commenters should 
not file proprietary or confidential business information in the 
docket. Such information must be sent or delivered directly to the 
person identified in the FOR FURTHER INFORMATION CONTACT section of 
this document, and marked as proprietary or confidential. If submitting 
information on a disk or CD ROM, mark the outside of the disk or CD 
ROM, and identify electronically within the disk or CD ROM the specific 
information that is proprietary or confidential.
    Under 14 CFR 11.35(b), if the FAA is aware of proprietary 
information filed with a comment, the agency does not place it in the 
docket. It is held in a separate file to which the public does not have 
access, and the FAA places a note in the docket that it has received 
it. If the FAA receives a request to examine or copy this information, 
it treats it as any other request under the Freedom of Information Act 
(5 U.S.C. 552). The FAA processes such a request under Department of 
Transportation procedures found in 49 CFR part 7.

F. Availability of Rulemaking Documents

    An electronic copy of rulemaking documents may be obtained from the 
internet by--
    1. Searching the Federal eRulemaking Portal (http://www.regulations.gov);
    2. Visiting the FAA's Regulations and Policies web page at http://www.faa.gov/regulations_policies or

[[Page 21738]]

    3. Accessing the Government Printing Office's web page at http://www.gpo.gov/fdsys/.
    Copies may also be obtained by sending a request to the Federal 
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence 
Avenue SW, Washington, DC 20591, or by calling (202) 267-9680. 
Commenters must identify the docket or notice number of this 
rulemaking.
    All documents the FAA considered in developing this proposed rule, 
including economic analyses and technical reports, may be accessed from 
the internet through the Federal eRulemaking Portal referenced in item 
(1) above.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

The Proposed Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration proposes to amend chapter I of title 14, Code of Federal 
Regulations as follows:

PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES

0
1. The authority citation for part 25 continues to read as follows:

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

0
2. Amend Sec.  25.365 by revising paragraph (g) to read as follows:

Sec.  25.365  Pressurized compartment loads.

* * * * *
    (g)(1) Except as provided in paragraph (g)(2) of this section, 
bulkheads, floors, and partitions in pressurized compartments for 
occupants must be designed to withstand the conditions specified in 
paragraph (e) of this section. In addition, reasonable design 
precautions must be taken to minimize the probability of parts becoming 
detached and injuring occupants while in their seats.
    (2) Partitions adjacent to the opening specified in paragraph 
(e)(2) of this section need not be designed to withstand that condition 
provided--
    (i) Failure of the partition would not interfere with continued 
safe flight and landing; and
    (ii) The applicant shows that designing the partition to withstand 
the condition specified in paragraph (e)(2) of this section would be 
impractical.

    Issued under authority provided by 49 U.S.C. 106(f), 44701(a), 
and 44703 in Washington, DC, on May 3, 2019.
Earl Lawrence,
Executive Director, Aircraft Certification Service.
[FR Doc. 2019-09823 Filed 5-14-19; 8:45 am]
 BILLING CODE 4910-13-P