[Federal Register Volume 89, Number 17 (Thursday, January 25, 2024)]
[Proposed Rules]
[Pages 4841-4856]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-01485]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 21

[Docket No.: FAA-2024-0159; Notice No. 24-10]
RIN 2120-AL87


Disclosure of Safety Critical Information

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This proposed rule would implement certain mandates in the 
Aircraft Certification, Safety, and Accountability Act of 2020 by 
requiring applicants for, and holders of, new and amended transport 
category airplane type certificates to submit, and subsequently 
continue to disclose, certain safety critical information to the FAA. 
The proposed rule would also require all applicants for type 
certificates, including new, amended, and supplemental type 
certificates, to submit a proposed certification plan to the FAA.

DATES: Send comments on or before March 25, 2024.

ADDRESSES: Send comments identified by docket number FAA-2024-0159 
using any of the following methods:
    <bullet> Federal eRulemaking Portal:
    <bullet> Go to www.regulations.gov and follow the online 
instructions for sending your comments electronically.
    <bullet> 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.
    <bullet> 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.
    <bullet> Fax: Fax comments to Docket Operations at (202) 493-2251.
    Docket: Background documents or comments received may be read at 
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: Susan McCormick, Systems Standards, 
Product Policy Management, Policy and Standards Division, Aircraft 
Certification Service, Federal Aviation Administration, 26805 East 68th 
Ave., Denver, CO 80249-6339; telephone (206) 231-3242; email 
<a href="/cdn-cgi/l/email-protection#f88b8d8b9996d6959b9b978a95919b93b89e9999d69f978e"><span class="__cf_email__" data-cfemail="a6d5d3d5c7c888cbc5c5c9d4cbcfc5cde6c0c7c788c1c9d0">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary
II. Background
    A. Congressional Mandate
    B. Regulatory Background (FAA Certification and Oversight 
Processes)
    C. Factual Background (Boeing 737 MAX Accidents and Ensuing 
Investigations)
    D. Legislation Resulting From Reviews of the 737 MAX
III. Authority for This Rulemaking
IV. Discussion of the Proposal
    A. Submittal of Proposed Certification Plans by Applicants
    B. Milestone Component of Applicant's Proposed Certification 
Plan
    C. Updating Transport Category Airplane Certification Plans With 
Safety Critical Information
    D. Continuing Disclosure Requirement for New and Amended 
Transport Category Airplane TC Applications

[[Page 4842]]

    E. Submittal Requirement for Holders of Transport Category 
Airplane TCs Covered Under Part 25
    F. Requirement For Subsequent Continuing Disclosure by TC 
Holders of Transport Category Airplanes Covered Under Part 25
    G. Interaction of This Proposal With Current Submittal and 
Disclosure Requirements
    H. Explanations of Five Categories of Safety Critical 
Information
V. Regulatory Notices and Analyses
    A. Regulatory Impact Analysis
    B. Regulatory Flexibility Act
    C. International Trade Impact Assessment
    D. Unfunded Mandates Assessment
    E. Paperwork Reduction Act
    F. International Compatibility
    G. Environmental Analysis
VI. Executive Order Determinations
    A. Executive Order 13132, Federalism
    B. Executive Order 13175, Consultation and Coordination With 
Indian Tribal Governments
    C. Executive Order 13211, Regulations That Significantly Affect 
Energy Supply, Distribution, or Use
    D. Executive Order 13609, Promoting International Regulatory 
Cooperation
VII. Additional Information
    A. Comments Invited
    B. Confidential Business Information
    C. Electronic Access and Filing
    D. Small Business Regulatory Enforcement Fairness Act

I. Executive Summary

    This proposed rule would implement certain mandates of section 105 
of the Aircraft Certification, Safety, and Accountability Act \1\ 
(ACSAA). It proposes to require applicants for, and holders of, type 
certificates (TCs), including new and amended but not including 
supplemental type certificates (STCs), for a transport category 
airplane covered under part 25 of title 14, Code of Federal Regulations 
(14 CFR), to submit, and subsequently continue to disclose, certain 
safety critical information to the FAA. Applicants would be required to 
submit such information as part of a certification plan.
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    \1\ Division V, title 1 of Consolidated Appropriations Act, 
2021. Public Law 116-260 (Dec. 27, 2020).
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    A certification plan would therefore be required, by regulation, 
for all applicants for TCs, including STCs, and would be required to 
include proposed milestones. After the FAA agrees to the certification 
plan, applicants would be required to keep it updated throughout the 
certification process.
    This proposal also includes requirements applicable to certain 
holders of TCs. Holders of transport category airplane TCs covered 
under part 25 would be required, within 90 days of the effective date 
of a final rule, to submit certain safety critical information, if 
known and not previously submitted. Such holders would thereafter be 
required to continue to disclose such information upon discovery. While 
TC holders already submit much of this information via requirements 
found in Sec. Sec.  21.3 and 183.63, this rule would require specific 
delineation of the safety critical information by the holder.
    Because the FAA's proposal would largely align the new submittal 
and disclosure requirements for TC applicants and holders with existing 
certification and oversight practices and require holders only to 
submit known and previously-undisclosed information, the incremental 
costs of the proposal would be minimal. The FAA has found potential 
benefits from the proposal due to the projected enhancement of the 
identification, and the agency's receipt of, safety critical 
information.

II. Background

A. Congressional Mandate

    On December 21, 2020, Congress passed the Consolidated 
Appropriations Act of 2021, which included the Aircraft Certification, 
Safety, and Accountability Act (Division V, Title 1). Section 105 of 
the Act was codified in title 49 U.S.C. 44704(e) (2021). Section 105 
instructs the FAA to require the submittal, and subsequent ongoing 
disclosure, of certain information related to TCs for transport 
category airplanes covered under part 25 of title 14.
    Section 105(e)(1), now 49 U.S.C. 44704(e)(1), prompts the FAA to 
require an applicant for, or holder of, a TC for a transport category 
airplane to submit safety critical information to the FAA. That section 
defines five categories of required safety critical information, as 
summarized below. It allows the FAA to set the form, manner, and time 
of the submittal.
    Section 105(e)(1)'s requirements are accompanied by certain 
caveats. First, as noted above, it applies to only those TCs for 
transport category airplanes that are ``covered under part 25 of title 
14.'' Second, the section states that the required submittals are to be 
made ``(N)otwithstanding a delegation described in section 44702(d).'' 
\2\ Third, section 105 defines the transport airplane type 
certificatess that are subject to its requirements as those for ``new 
or amended'' certificates, but excludes STCs.
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    \2\ Section 44702(d) of title 49 allows the Administrator to 
delegate certain matters related to type certificates and other 
certificates.
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    Section 105 also directs certain ``Ongoing Communications.'' 
Specifically, Section 105(e)(2)(A) instructs the FAA to require that an 
applicant for, or holder of, a transport airplane type certificate 
disclose to the FAA any newly discovered information, or any design or 
analysis change, that would materially alter the applicant or holder's 
prior submission of safety critical information to the FAA under 
section 105(e)(1). As with the initial disclosure requirement, this 
section allows the FAA to set the form, manner, and time of the 
communication. Section 105(e)(2)(b) directs the FAA to establish 
milestones throughout the certification process at which the systems of 
a proposed transport category airplane design will be assessed. These 
required assessments must determine whether a change made to a system 
during the certification process should prompt the FAA to consider the 
system as novel or unusual.
    Section 105 sets forth five categories of safety critical 
information that applicants or holders must submit and disclose. These 
categories generally relate to information about the proposed design's 
potential to affect the flightcrew's ability to control the airplane, 
and about the analysis of potential hazards that could be posed by the 
design. The following paragraphs summarize the five categories of 
safety critical information.
    (1) Details, functions, and failure modes of any system that, 
without being commanded by the flightcrew, could command the operation 
of a function or feature that is necessary for control of the airplane, 
or could affect its flight path or airspeed.
    (2) Details, functions, failure modes, and mode annunciations about 
the transport category airplane's autopilot and autothrottle systems.
    (3) Failures or operating conditions that the TC applicant or 
holder anticipates or has concluded would result in a hazardous or 
catastrophic outcome.
    (4) Any adverse handling quality that, without adding flight 
control augmenting software to the airplane design, would result in a 
failure to meet the requirements of FAA regulations.
    (5) A system safety assessment with respect to any system described 
in one of the first two categories (i.e., flight controls, and 
autothrottle/autopilot), or with respect to a system or component whose 
failure or erroneous operation could result in a hazardous or 
catastrophic outcome.

[[Page 4843]]

B. Regulatory Background (FAA Certification and Oversight Processes)

    The FAA reviews applicants' proposed designs of products such as 
airplanes and engines, and, if it finds that the design meets 
regulatory standards, issues a design approval known as a ``type 
certificate.'' For transport category airplanes, which are used by air 
carriers to transport the public in scheduled service, the FAA reviews 
proposed designs primarily using the standards in 14 CFR part 25. Part 
25 replaced part 4b of the Civil Air Regulations in 1965.\3\ The FAA 
provides applicants with suggested, but optional, means of compliance 
with many design standards via the publication of guidance documents 
such as advisory circulars (AC).
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    \3\ 29 FR 18289.
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    After obtaining a TC for a transport category airplane from the 
FAA, most TC holders obtain (or seek to amend) a production 
certificate, which the FAA issues after the manufacturer proves that it 
is capable of repeatedly building the product according to its approved 
design. After an individual aircraft is built, the FAA issues an 
airworthiness certificate after finding that the aircraft conforms to 
its design and is in a condition for safe operation.
1. Relevant Part 25 Design Standards
    Several part 25 design standards for transport category airplanes 
are relevant to the safety critical information that Congress has 
defined, and directed the FAA to require from, TC applicants and 
holders.
a. System Safety Assessment
    To ensure the reliability of proposed designs for transport 
category airplanes, the FAA requires applicants to analyze the 
potential effects that failures and malfunctions could have on the 
airplane and its flightcrew. Among the FAA's reliability regulations 
for transport category airplanes is Sec.  25.1309, which generally 
requires the likelihood of a failure to be inversely proportional to 
its potential effect. Specifically, it requires that any failure 
condition which could cause the loss of the airplane (a 
``catastrophic'' failure condition) to be so unlikely as to never occur 
during the expected lifetime of all airplanes of that model (i.e., 
``extremely improbable'' with an associated per hour failure rate of 
10<SUP>-9</SUP>, or less likely than one event per 10\9\ (billion) 
flight hours).\4\ Section 25.1309 also requires that failure conditions 
which are not catastrophic, but which nevertheless could reduce the 
capability of the airplane or the ability of its flightcrew to cope 
with adverse operating conditions (a ``major'' failure condition), to 
be no more likely than improbable (an associated per-hour failure rate 
between every 10<SUP>-9</SUP> and 10<SUP>-5</SUP> flight hours).\5\ The 
requirement to analyze these catastrophic and major failure conditions, 
and thus submit that information to the FAA, has been in place since 
1970.\6\
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    \4\ AC 25.1309-1A, System Design and Analysis (June 21, 1988), 
page 15, paragraph 10.b.(3), available in the docket and at 
drs.faa.gov.
    \5\ AC 25.1309-1A, page 15, paragraph 10.b.(2), available in the 
docket and at drs.faa.gov.
    \6\ Amendment 25-23, 35 FR 5665.
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    An FAA-approved means of compliance with 14 CFR 25.1309 is AC 
25.1309-1A, System Design and Analysis (June 21, 1988).\7\ This AC 
divides the foregoing failure conditions into three categories, 
aligning their severity with their likelihood: (1) Catastrophic (which 
may be no more likely than 10<SUP>-9</SUP>, or extremely improbable); 
(2) Major (between 10<SUP>-9</SUP> and 10<SUP>-5</SUP>, or improbable); 
and (3) Minor, which are unregulated for transport category airplanes 
and may be probable (more likely than 10<SUP>-5</SUP>). An additional 
Aviation Rulemaking Advisory Committee (ARAC) \8\-recommended version 
\9\ of this guidance, known as the ``Arsenal'' version, divides the 
``major'' category into two categories of failures: those that are 
``hazardous'' (from 10<SUP>-9</SUP> to 10<SUP>-7</SUP>) and those that 
are ``major'' (from 10<SUP>-7</SUP> to 10<SUP>-5</SUP>).\10\ Some 
applicants use the guidance in this version when developing their 
system safety assessments (SSA), and the FAA commonly accepts such 
assessments as a means of showing that the proposed design complies 
with Sec.  25.1309.
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    \7\ Available in the docket.
    \8\ The ARAC was created under the Federal Advisory Committee 
Act (FACA), in accordance with title 5 of the United States Code (5 
U.S.C. App. 2) to provide advice and recommendations to the FAA 
concerning rulemaking activities, such as aircraft operations, 
airman and air agency certification, airworthiness standards and 
certification, airports, maintenance, noise, and training.
    \9\ The Arsenal version is a draft revision of AC 25.1309-1A. It 
was developed by the ARAC Systems Design and Analysis Harmonization 
Working Group (SDAHWG). It is in the docket for this rulemaking as 
part of the SDAHWG recommendation, Task 2-System and Analysis 
Harmonization and Technology Update, pp. 61-99.
    \10\ The FAA has proposed to update 14 CFR 25.1309, including 
changes seeking to ensure that applicants protect the airplane from 
the effects of the combination of two failures, the first of which 
is undetected until a second failure occurs. Docket No. FAA-2022-
1544, available at regulations.gov.
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    In some cases, the applicant submits the SSA to a designee of the 
FAA. Designees of the FAA can be individual or organizational. 
Organizational designees are known as ODAs because the FAA has granted 
them ``organization designation authorization.'' \11\ Thus, an 
applicant may be submitting its SSA and other compliance information to 
an entity other than the FAA itself, if the FAA has authorized that 
entity to make a finding of compliance on the FAA's behalf.
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    \11\ See subpart D of 14 CFR part 183.
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b. Function and Installation of Equipment
    The FAA's reliability standards for transport category airplanes 
certified under part 25 also include Sec.  25.1301(a)(4), which 
requires that each item of installed equipment on the airplane function 
properly when installed. Implementing policy for Sec.  25.1301 is 
included in several ACs, such as AC 20-174, Development of Civil 
Aircraft and Systems, and AC 25.1329-1, Approval of Flight Guidance 
Systems.
c. Other Relevant Part 25 Design Standards
    Additional part 25 standards of potential relevance to safety 
critical information as defined by Congress, are Sec.  25.143, general 
flight maneuvers; Sec.  25.672, which governs stability augmentation 
and automatic and power-operated systems; Sec.  25.1322, for flightcrew 
alerting; and Sec.  25.1329, which governs flight guidance systems. The 
foregoing part 25 regulations, which current applicants for transport 
category airplane TCs must show that their proposed design complies 
with,\12\ are pertinent to the ACSAA section 105 requirements for 
applicants and holders of TCs for transport category airplanes to 
submit, and continue to disclose, certain safety critical information.
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    \12\ Per 14 CFR 21.20 and 21.21.
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2. Applicant Certification Plans
    An applicant has 5 years, from the date of application, to obtain 
FAA approval of the applicant's proposed transport category airplane 
TC, or change to such certificate.\13\ To ensure that necessary 
information about an applicant's project is submitted in time for the 
FAA to adequately review, to establish an agreed-upon schedule 
including milestones, and to identify potential issues, applicants 
submit a proposed certification plan for their project,\14\ at the time 
of application, to

[[Page 4844]]

the FAA.\15\ A certification plan includes several categories of 
information.\16\ Such information includes general information about 
the proposed design, but also specific information such as a 
description of how compliance will be shown, a list of the 
documentation that the applicant plans to use to show compliance, and 
the applicant's expected certification date. Applicants also generally 
keep this information updated throughout the development of their 
project, so that they can show compliance with FAA design standards, 
and so that the FAA has correct information to make the findings of 
compliance that are necessary to issue the requested TC.
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    \13\ 14 CFR 21.17(c) and 21.101(e).
    \14\ Certification plans are submitted by nearly all project 
applicants, because the plans are a useful tool for both the FAA and 
industry. FAA Order 8110.4C provides information on their use. Also, 
the FAA and industry jointly developed both the The FAA and Industry 
Guide to Product Certification (i.e., Certification Process Guide 
(CPG)) and the Enhanced Project Specific Certification Plan (ePSCP) 
Guide (i.e., ePSCP Guide) as a means to communicate project 
information via certification plans.
    \15\ Section 2-3 of FAA Order 8110.4C.
    \16\ Id. at para. 2-3(d).
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3. Disclosure of Novel or Unusual Design Features
    Since each proposal for an original or amended TC is different, and 
the designs of modern transport category airplanes are complex, 
proposed designs will inevitably present multiple issues, whether 
technical, regulatory, or administrative, that require a heightened 
degree of analysis by the FAA and engagement with the applicant. The 
FAA analyzes such issues via the development of issue papers.\17\
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    \17\ See FAA Order 8110.4C, at para 2-4(g); FAA Order 8110.112; 
and AC 20-166B.
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    If a proposed design feature is novel or unusual (i.e., it was not 
envisaged by FAA design standards) and therefore, the FAA's design 
standards are inadequate or inappropriate for that feature, the FAA 
addresses that feature with a rule of particular applicability known as 
a ``special condition.'' \18\ Though the goal is to identify and 
address novel or unusual design features early in the certification 
process, regular discussions (e.g., familiarization briefings, 
compliance planning meetings, etc.) between the applicant and the FAA 
are necessary to plan and execute certification activities.
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    \18\ 14 CFR 21.16.
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4. Existing 14 CFR 21.3 Reporting of Failures, Malfunctions, and 
Defects
    In 1969, the FAA noted that while air carriers were required to 
notify the FAA of certain safety issues occurring on their airplanes 
and engines, it is the manufacturers of those products who have the

``expertise . . . to evaluate the seriousness of the failure, 
defect, or malfunction, and to determine the extent to which (it) 
may present a hazard to flight.'' \19\
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    \19\ 34 FR 5441.

    The FAA thus proposed, and subsequently issued, a rule--14 CFR 
21.3--requiring manufacturers to promptly \20\ inform the FAA of the 
occurrence of a host of listed failures, defects, and malfunctions. The 
specific items to be disclosed have not substantively changed in the 
half-century since the rule was issued.
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    \20\ Within 24 hours, or by the end of the next business day. 14 
CFR 21.3(e)(1).
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    Thus, after the FAA approves a proposed design via the issuance of 
a TC, and the manufacturer builds its product according to that 
approved design, and the individual aircraft receives a certificate of 
airworthiness and enters service, the manufacturer's obligation to 
ensure the airworthiness of its product continues. The manufacturer 
must report certain information to the FAA in accordance with Sec.  
21.3. If the FAA determines a design change is required to correct an 
unsafe condition in a product, the manufacturer is required by Sec.  
21.99 to submit a proposed change to its design, and the FAA may 
mandate this change via part 39 of 14 CFR by the issuance of an 
airworthiness directive (AD).
5. Other Ongoing Disclosure Requirements Applicable to TC Holders
    Nearly every domestic holder of an original or amended TC for a 
part 25 transport category airplane in the U.S. is also the holder of 
an ODA.\21\ ODA holders are required by current regulations to submit 
and disclose several categories of safety information to the FAA. Two 
categories are of particular pertinence to the requirements that this 
NPRM proposes to establish. Section 183.63(b)(1) requires ODA holders, 
without prompting by the FAA, to notify the agency of any ``condition 
in a product, part or appliance that could result in a finding of 
unsafe condition by the Administrator.'' Section 183.63(b)(2) requires 
ODA holders to notify the agency of products not meeting airworthiness 
requirements.
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    \21\ The exception is Lockheed Martin Corporation. The Boeing 
Company, Gulfstream Aerospace Corp., Textron Aviation Inc., Piper 
Aircraft, Inc., and LearJet, Inc. are all currently ODA holders.
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    FAA policy provides guidance on the details of the provision of 
such information.\22\ The ODA holder must provide continued support for 
approvals or certificates issued under ODA procedures in accordance 
with Sec.  183.63. Procedures for monitoring service information, 
investigation, and FAA notification must be included in the ODA 
holder's FAA-approved procedures manual, in accordance with Sec.  
183.53(c)(13).
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    \22\ FAA Order 8100.15B at section 3-18.
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C. Factual Background (Boeing 737 MAX <SUP>23</SUP> Accidents and 
Ensuing Investigations)
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    \23\ When the term ``737 MAX'' is used in this NPRM, it is 
referring to the Boeing Model 737-8 and -9 airplanes.
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    The following information, due to its inclusion or reference in 
investigations by Congressional committees, was pertinent to the 
development of the Congressional requirements that this NPRM proposes 
to implement.\24\
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    \24\ See, e.g., House Report H.R. 8408, H. Rept. 116-579--
AIRCRAFT CERTIFICATION REFORM AND ACCOUNTABILITY ACT [verbar] 
Congress.gov [verbar] Library of Congress. Available in the docket.
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    The FAA approved the amended TC for the Boeing Model 737-8 in 2017. 
On October 29, 2018, a Boeing Model 737-8 airplane operated by Lion Air 
(Lion Air Flight 610) was involved in an accident after takeoff in 
Indonesia, resulting in 189 fatalities. The accident was investigated 
by the Indonesian authorities (Komite Nasional Keselamatan Transportasi 
(KNKT)) \25\ with assistance from the National Transportation Safety 
Board (NTSB), the FAA, the manufacturer, and the operator.
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    \25\ Preliminary KNKT.18.10.35.04 Aircraft Accident 
Investigation Report, dated November 2018, and Final 
KNKT.18.10.35.04 Aircraft Accident Investigation Report, dated 
October 2019, can be found in the docket.
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    On March 10, 2019, a Boeing Model 737-8 airplane operated by 
Ethiopian Airlines (Ethiopian Airlines Flight 302) was involved in an 
accident after takeoff in Ethiopia, resulting in 157 fatalities. The 
accident was investigated by the Ethiopian Accident Investigation 
Bureau \26\ with assistance from the NTSB, the FAA, the French Bureau 
of Enquiry and Analysis for Civil Aviation Safety, the European Union 
Aviation Safety Agency, the manufacturer, the operator, and the 
Ethiopian Civil Aviation Authority.
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    \26\ Report No. AI 01/19, Interim Investigation Report on 
Accident to the B737-8 (MAX) Registered ET-AVJ operated by Ethiopian 
Airlines on 10 March 2019, dated March 9, 2020, of the Federal 
Democratic Republic of Ethiopia Ministry of Transport Aircraft 
Accident Investigation Bureau, can be found in the docket.
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    The investigations of these accidents generally found that 
erroneous data from one of the airplane's two angle-of-attack sensors 
could cause the maneuvering characteristics augmentation system (MCAS), 
a function of the airplane's flight control software, to command 
repeated airplane nose-down trim of the horizontal stabilizer, and 
could result in flightdeck

[[Page 4845]]

effects that collectively could affect the ability of the flightcrew to 
accomplish continued safe flight and landing.\27\
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    \27\ See, e.g., p. 7 of NTSB ASR-19-01, Assumptions Used in the 
Safety Assessment Process and the Effects of Multiple Alerts and 
Indications on Pilot Performance, dated September 19, 2019, (``ASR-
19-01''), available in the docket.
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    Flightdeck effects common to both accidents were differences in the 
altitude and airspeed displayed for each pilot and persistent stall 
warning. In the Ethiopian accident, the significant difference in 
airspeeds resulted in the autothrottle becoming inoperative, thus 
leaving the thrust levers at the current takeoff thrust setting. The 
throttles remained at takeoff power throughout the flight, resulting in 
high airspeed, which made it more difficult for the flightcrew to 
control the airplane.
    The Boeing Models 737-8 and 737-9 were certified via amendment of 
the existing Boeing Model 737 TC and were the first of a set of 
derivative models collectively marketed by Boeing as the 737 MAX. To 
certify the 737 MAX airplanes with larger and relocated engines, Boeing 
added MCAS to the airplane's flight control software so that the 
airplane handling qualities would comply with FAA design standards.\28\
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    \28\ See, e.g., pp. 23-24 of Summary of the FAA's Review of the 
Boeing 737 MAX (November 20, 2020), available in the docket.
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    Following the accidents, the FAA mandated corrective actions to 
address the unsafe condition related to MCAS on the 737 MAX. The 
actions included requiring changes to the airplane's flight control 
software related to MCAS and related flightcrew procedures. These 
changes were developed by Boeing and its ODA unit pursuant to 
Sec. Sec.  21.3, 21.99 and 183.63, and, after a public comment process, 
were required by the FAA via the issuance of an AD.\29\
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    \29\ 85 FR 74560.
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1. Investigations of Certification of 737 MAX and FAA Certification 
Processes
    The two accidents also led to investigations of how the Boeing 737 
MAX airplane had been certified by the FAA; of the FAA's delegation of 
certain certification functions to the Boeing ODA; and of how the FAA 
certifies transport category airplanes in general. These investigations 
included reviews by the NTSB \30\ and the U.S. Department of 
Transportation's Office of Inspector General (in June 2020 \31\ and 
February 2021 \32\); a Joint Aviation Technical Review conducted by a 
panel of foreign civil aviation authorities; \33\ and reviews by the 
Aviation Subcommittee of the U.S. House Committee on Transportation and 
Infrastructure \34\ and the U.S. Senate Committee on Commerce, Science, 
and Transportation.\35\ The FAA also performed and published its own 
technical summary when addressing the unsafe condition.\36\
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    \30\ System Safety and Certification Specialist's Report, 
DCA19RA017, dated August 21, 2019, and the aforementioned ASR-19-01, 
available in the docket.
    \31\ Timeline of Activities Leading to the Certification of the 
Boeing 737 MAX 8 Aircraft and Actions Taken After the October 2018 
Lion Air Accident, June 2020, (``OIG I''), available in the docket.
    \32\ Weaknesses in FAA's Certification and Delegation Processes 
Hindered Its Oversight of the 737 MAX 8, U.S. Department of 
Transportation Office of Inspector General, February 2021, (``OIG 
II'') available in the docket.
    \33\ Boeing 737 MAX Flight Control System Joint Authorities 
Technical Review, October 2019, (``JATR''), available in the docket.
    \34\ The Design, Development, & Certification of the Boeing 737 
MAX, Majority Staff of the U.S. House Committee on Transportation 
and Infrastructure, (``House Committee Report''), available in the 
docket.
    \35\ Aviation Safety Oversight, U.S. Senate Committee on 
Commerce, Science, & Transportation, December 2020, (``Senate 
Committee Report''), available in the docket.
    \36\ As referenced at footnote 28.
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2. Disclosure of Information During Certification of 737 MAX
    The investigations of the certification of the 737 MAX generally 
found that Boeing, as the applicant for an amended TC, inadequately 
disclosed certain information about its proposed design, and its 
potential safety risks, to the FAA during the certification 
process.\37\ This information included the manufacturer's increase of 
the authority (from 0.55 to 2.5 degrees of stabilizer movement) and 
circumstances (from high-altitude only, to relatively low altitude and 
airspeed) of the flight-control software's automatic (without pilot 
input) activation of MCAS to move the horizontal stabilizer of the 
airplane.\38\
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    \37\ See, e.g., JATR at pp. VII, 13, and 24-25; House Report at 
p. 57.
    \38\ See, e.g., House Report at p. 103; OIG I at p. 20; OIG II 
at p. 16.
---------------------------------------------------------------------------

    The investigations also generally found that Boeing's hazard and 
safety assessments of these systems on the 737 MAX did not adequately 
account for the severity of hazard that MCAS posed.\39\ According to 
the investigations, the hazard classifications for MCAS failures, given 
that system's potential reliance on a single angle-of-attack indicator, 
should have been catastrophic with an SSA that included commensurate 
rigor.\40\
---------------------------------------------------------------------------

    \39\ See, e.g., JATR at p. 30-31; OIG I at p. 25.
    \40\ See, e.g., House Report at pp. 13 and 29; JATR at pp. 31 
and 33-34.
---------------------------------------------------------------------------

    The investigations found that the company's SSAs that addressed 
MCAS considered the hazard from a single activation, but did not 
address the hazard that could be presented by repeated activations of 
MCAS.\41\
---------------------------------------------------------------------------

    \41\ See, e.g., House Report at pp. 21, 109, and 116; JATR at 
pp. 33-34.
---------------------------------------------------------------------------

D. Legislation Resulting From Reviews of the 737 MAX

    After the foregoing reviews of the FAA's certification of the 737 
MAX, in December of 2020 Congress passed the Aircraft Certification, 
Safety, and Accountability Act (ACSAA).\42\ ACSAA imposed many new 
requirements on the FAA, including those of section 105.
---------------------------------------------------------------------------

    \42\ Public Law 116-260 (ACSAA).
---------------------------------------------------------------------------

    Section 105's provisions generally seek to ensure that information 
about the potential hazards of a transport category airplane's systems 
is adequately disclosed by applicants for design approval, so that such 
information can be adequately evaluated by the applicant and the FAA.
    Section 105 does not apply these requirements only to 
``applicants,'' as it does certain other provisions. Rather, it also 
applies the initial submittal, and ongoing disclosure requirement, to 
the ``holder of'' a type certificate for a transport category airplane 
covered under part 25.

III. 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 FAA's authority.
    This proposed 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 prescribing regulations and 
minimum standards for the design and performance of aircraft that the 
Administrator finds necessary for safety in air commerce. This proposed 
regulation is within the scope of that authority.
    Authority for this particular rulemaking is derived from section 
105(a) of ACSAA. Section 105, ``Disclosure of Safety Critical 
Information,'' of ACSAA directs the Administrator of the FAA to require 
an applicant for, or holder of, a TC for a transport category airplane 
covered under 14 CFR part 25 to submit and disclose certain safety 
critical information to the FAA.

IV. Discussion of the Proposal

    In this rulemaking, the FAA proposes to impose, as required by 
section 105(a),

[[Page 4846]]

the initial submittal and continuing disclosure requirements of that 
section on applicants and holders of TCs, including amended TCs, for 
transport category airplanes covered by 14 CFR part 25.

A. Submittal of Proposed Certification Plans by Applicants

    In this NPRM, the FAA proposes a new Sec.  21.15(d) that would 
require applicants for new or amended TCs to submit proposed 
certification plans to the FAA, and that a new Sec.  21.113(c) would 
require the same for applicants for new or amended STCs. Consistent 
with current practice, such plans would be required to be submitted 
with the application. The proposed certification plans would be 
required to include planning information; proposed milestones; and, for 
transport category airplane applications, subsequent updates to include 
the safety critical information that ACSAA requires the FAA to obtain 
from such applicants.
    Under current practices, applicants typically submit a variety of 
information with their proposed certification plans, as described in 
FAA Order 8110.4C, Type Certification (for applicants) and 8100.15B, 
Organization Designation Authorization Procedures (for ODA holders) and 
associated materials such as The FAA and Industry Guide to Product 
Certification (i.e., Certification Process Guide \43\ (CPG)) and 
Enhanced Project Specific Certification Plan (ePSCP) Guide (i.e., ePSCP 
Guide).\44\ However, to provide transport category airplane applicants 
with a familiar vehicle for the initial submittal of safety critical 
information, the FAA proposes to establish a performance-based 
regulatory requirement for certification plans.
---------------------------------------------------------------------------

    \43\ Available in the docket and at www.faa.gov/sites/faa.gov/files/aircraft/air_cert/design_approvals/transport/CPI_guide.pdf.
    \44\ Available in the docket and at www.faa.gov/sites/faa.gov/files/aircraft/air_cert/design_approvals/dah/ePSCP_guide.pdf.
---------------------------------------------------------------------------

    Thus, proposed certification plans would be required, via a 
regulatory performance standard, to contain sufficient information for 
the applicant's showings of compliance, and the FAA's findings, to be 
timely and accurately made. The provided information would be 
substantially the same as described in the aforementioned FAA guidance 
documents. The information provided in the certification plan would 
need to be sufficiently developed, and detailed, to enable the FAA to 
determine its level of involvement for each compliance showing and 
finding, ensure prompt submittal of all necessary compliance data, and 
allow all showings and findings to be timely and accurately made for 
each project.
    The FAA proposes that applicants would be required to submit these 
proposed certification plans in a manner consistent with current 
practices. Thus, applicants would be required to submit certain 
preliminary key project information, specifically the applicant's 
proposed certification basis; \45\ a compliance checklist that 
identifies the means by which the applicant plans to show that it 
complies with FAA regulations, and that identifies all deliverables 
\46\ that the applicant anticipates will be necessary to show 
compliance; and a proposed project schedule with milestones. Applicants 
for transport category airplane new or amended, but not supplemental, 
type certificates would be required to include their expected 
certification date as part of this proposed schedule. The certification 
plan would also be required to identify any other information that the 
applicant anticipates will be necessary to enable the applicant's 
showings and certifying statement (per Sec.  21.20) and the FAA's 
findings of compliance (per Sec.  21.21(b)) to be timely and accurately 
made.
---------------------------------------------------------------------------

    \45\ A proposed certification basis includes applicable 
regulation paragraphs with amendment levels, and the potential need 
for the FAA to issue exemptions, equivalent level of safety findings 
(ELOSs), and special conditions. See FAA Order 8110.4C at section 2-
3(d).
    \46\ Per current practices, these would include items such as 
test plans, reports, analyses (often called ``deliverables'', 
``documents'', or ``document deliverables''), and inspections that 
are necessary to show compliance with the applicable requirements.
---------------------------------------------------------------------------

    Under current practices, it is common for applicants to describe 
safety critical information as deliverables within the compliance 
checklist, and include preliminary system safety assessment sections 
and referenced documentation. The FAA anticipates that this practice 
would continue, under the new standard for the contents of proposed 
certification plans. FAA Order 8110.4C and the ePSCP Guide would still 
provide applicants with additional information and best practices for 
submittals to meet the new regulatory requirements.

B. Milestone Component of Applicant's Proposed Certification Plan

    TC applicants generally propose a project schedule as part of their 
certification plan. This proposed project schedule includes key events, 
called milestones. Typical milestones include familiarization meetings, 
submittal of issue papers (to develop the resolution of issues that may 
necessitate determinations such as special conditions, ELOSs, and 
exemptions), type board meetings, first airplane flight, data submittal 
requirements, inspection/conformity dates, and associated test dates.
    In addition to the typical milestones that the applicant and the 
FAA use to plan the development and review of the project, the proposed 
schedule would, for applications for new or amended TCs for transport 
category airplanes, need to include sufficient milestones to enable 
compliance with requirements of the proposed rule. Such milestones 
would be consistent with current practices, and would include dates for 
submitting certain compliance documents such as safety assessments 
(including functional hazard assessments, fault tree analyses, the 
requirements validation plan, software development documents, and 
minimum training requirements \47\ and other data to support the flight 
standardization board report and revisions (as needed).
---------------------------------------------------------------------------

    \47\ 14 CFR 121, subpart N defines operator training programs.
---------------------------------------------------------------------------

    Under current practices, an applicant's initial proposed 
certification plan also necessitates subsequent updates. These planned 
updates are, and under this proposal would continue to be, included as 
milestones within the proposed certification plan. This would establish 
``gates'' throughout the certification process at which a proposed 
airplane system will be assessed for changes and impacts to the overall 
certification approach (e.g., certification basis, traceability, 
compliance dependencies, means of compliance, etc.) for the project.
    In summary, the foregoing milestones would be used to monitor, 
review, and assess the progress of the proposed airplane design and 
systems toward compliance, jointly by the FAA and the applicant.

C. Updating Transport Category Airplane Certification Plans With Safety 
Critical Information

    This proposal would require applicants for new and amended TCs for 
transport category airplanes to submit safety critical information as 
an update to the certification plan that proposed Sec.  21.15(d) would 
require. Proposed Sec.  21.15(e) would require that this update to the 
applicant's certification plan include or describe all of the safety 
critical information set forth in proposed Sec.  21.1(c). An 
explanation of each of these five categories of safety critical 
information is set forth later in this proposal.
    Regarding the level of detail to be provided with the submittal of 
safety critical information with the

[[Page 4847]]

certification plan update under Sec.  21.15(e), the FAA recognizes that 
the type design for a transport category airplane project may not be 
sufficiently developed at the time of initial submittal to include a 
thorough discussion of all safety critical information.
    Applicants would be required to describe safety critical 
information in the update required by proposed Sec.  21.15(e). This 
safety critical information would be as described elsewhere in this 
NPRM. The certification plan update would also include the anticipated 
relevant deliverables that are necessary to accomplish the requirements 
of the certification plan. This initial submittal of safety critical 
information with the certification plan update would be one step in the 
iterative process that builds toward the applicant's eventual 
compliance showings with certain regulations.
    For example, the safety assessment process is often used by 
applicants to show compliance with certain regulatory design standards 
that are relevant to the section 105 categories of safety critical 
information, such as Sec.  25.1309. Common and FAA -accepted means of 
compliance with that regulation are SAE Aerospace Recommended Practice 
(ARP)4761, ``Guidelines and Methods for Conducting the Safety 
Assessment Process on Civil Airborne Systems and Equipment,'' AC 
25.1309-1A, and the ``Arsenal'' version of AC 25.1309-1A,\48\ which 
include safety assessment techniques. As previously noted in this NPRM, 
the ``Arsenal'' version of AC 25.1309-1A, has been accepted since 2001 
when used in conjunction with an equivalent level of safety finding. 
That AC documents an established means for an applicant to show 
compliance to regulations, such as Sec.  25.1309, related to safety 
critical information. Thus, the deliverables provided by these means of 
compliance are, and under this proposal would continue to be, regularly 
reviewed at proposed milestones.
---------------------------------------------------------------------------

    \48\ See footnote 9.
---------------------------------------------------------------------------

    The FAA proposes that requiring the submittal of safety critical 
information, even in preliminary form, at the time of application could 
be unreasonably early, given the likely state of the proposed design, 
especially for complex projects or new TCs. Thus, to implement this 
requirement to submit safety critical information, applicants for new 
or amended transport category airplane TCs would be required to 
identify, as part of their initial proposed certification plan, their 
expected (requested) certification date. This would align with current 
practice. Then, to ensure that the FAA has adequate time to review the 
safety critical information, the transport category airplane applicant 
would be required to submit that safety critical information no later 
than 6 months prior to the applicant's requested certification date, or 
within one year of submittal of the application, whichever is earlier. 
The FAA requests comment on these proposed timeframes.
    Section 105 begins with ``Notwithstanding a delegation described in 
section 44702(d). . .'' Section 44702(d) authorizes the Administrator 
to delegate, to qualified private persons, certain matters related to 
the issuance of certificates, including type certificates. Therefore, 
the FAA proposes in this NPRM that all new submittals, and all ongoing 
disclosures, of safety critical information, by applicants be made to 
the FAA itself, not to any individual or organizational designee.
    This initial submittal would not end the applicant's obligation to 
provide safety critical information to the FAA. Section 105 
distinguishes between two required obligations: of the initial 
submittal, and then the ongoing disclosure, of safety critical 
information.

D. Continuing Disclosure Requirement for New and Amended Transport 
Category Airplane TC Applications

    Proposed Sec.  21.15(f) would require transport category airplane 
applicants, for the remainder of the certification process, to inform 
the FAA, within 3 business days of discovery, of any information or 
proposed design or analysis change that would materially alter \49\ 
their previously-submitted safety critical information.
---------------------------------------------------------------------------

    \49\ ``Materially alter'' would mean potentially affecting or 
negating a compliance showing, a certification assumption (e.g., 
design, human factors, operational training, etc.), or the FAA's 
level of involvement (e.g., delegation decisions).
---------------------------------------------------------------------------

    An example of such a proposed ``design or analysis change'' would 
be the discovery that a system safety analysis that the applicant 
previously submitted pursuant to this proposal, or was planned to be 
used as part of the applicant's showing of compliance with Sec.  
25.1309, erroneously misstated the likelihood of a hazard. This 
disclosure could be the applicant's identification of an error in a 
fault tree analysis.
    The FAA proposes that such design or analysis change would be 
required to be submitted within 3 days of discovery, rather than later, 
due to the potential importance of this information to safety and 
compliance, and to minimize the likelihood that the change delays the 
project.

E. Submittal Requirement for Holders of Transport Category Airplane TCs 
Covered Under Part 25

    Proposed Sec.  21.3(g) would require each holder (except STC 
holders) of a transport category airplane TC covered under part 25, 
within 90 days of the effective date of the final rule, to submit 
categories of safety critical information, if known and if not 
previously submitted, to the FAA for each model. The categories of 
required safety critical information for holders would be the same as 
for applicants, and would be defined in proposed Sec.  21.1(c).\50\
---------------------------------------------------------------------------

    \50\ As with the requirement for applicants, athough a 
supplemental type certificate is a form of type certificate (14 CFR 
21.20), per section 105 there would be no requirement for submittal 
of safety critical information that would be triggered by the 
holding of STCs covered under part 25, only by the holding of 
original and amended type certificates.
---------------------------------------------------------------------------

    The FAA does not expect this submittal to be voluminous, or its 
preparation burdensome or overly time-consuming. First, much of the 
required safety critical information will have already been submitted 
to the FAA, through the TC application and certification process. 
Safety critical information is included in the type design, operating 
limitations, substantiation documents, and other required information 
as a part of the TC.
    Also, the FAA proposes that holders would be required to submit 
such information if ``known'' The purpose of this proposed limitation 
is to clarify that the new submittal requirement would not be intended 
to prompt all holders of transport category airplane TCs covered under 
part 25 to reevaluate all of their safety critical information for 
previously-approved designs, or interview past employees. Rather, 
safety critical information is ``known'' to the holder if any FAA 
designee including ODA staff (including administrators and unit 
members), any current manager \51\ or responsible agent of the TC 
holder, or any employee of the TC holder with authority over or 
involvement in certification activities has knowledge of the 
information.
---------------------------------------------------------------------------

    \51\ The FAA intends that ``manager'' would not be limited to 
persons who supervise other persons, and would also include other 
persons with managerial duties, including program managers, project 
managers, risk managers, safety managers, etc.
---------------------------------------------------------------------------

    The FAA also proposes that previously-submitted information would 
not need to be resubmitted by TC holders or ODA holders to the FAA. As 
noted above, much of this information will have been previously 
submitted by

[[Page 4848]]

the holder, as part of the type certification process. While section 
105(a) begins with ``[n]otwithstanding a delegation,'' the FAA does not 
consider that limitation to be retrospective. Thus, the previous 
submittal to a representative of the FAA \52\ that was authorized to 
make a compliance finding on the agency's behalf, would qualify as 
having been previously submitted.
---------------------------------------------------------------------------

    \52\ The FAA proposes that this allowance would only apply to 
organizational, not individual, designees. Only submittals that were 
previously made to Representatives of the Administrator authorized 
in accordance with 14 CFR part 183, subpart D would qualify.
---------------------------------------------------------------------------

    The FAA further proposes to limit the scope of this submittal 
requirement, and the ongoing disclosure requirement described in the 
next section, to just those transport category airplane TC holders 
whose airplanes are ``covered under part 25 [of title 14].'' This would 
make the proposal consistent with the text of section 105. It would 
thus exclude transport category airplanes that do not have 14 CFR part 
25 in their certification basis.

F. Requirement for Subsequent Continuing Disclosure by TC Holders of 
Transport Category Airplanes Covered Under Part 25

    Proposed Sec.  21.3(g), beginning 90 days after the effective date 
of the proposed rule, would require TC holders, should they become 
aware of any newly discovered safety critical information, or a design 
or analysis change that would materially alter \53\ any submission to 
the FAA of the information defined under Sec.  21.1(c), to disclose 
such information to the FAA within 3 business days of the discovery. 
Like the mandated submittal of safety critical information by holders, 
this ongoing disclosure would be required to be made to the FAA itself, 
not to a designee such as an ODA.
---------------------------------------------------------------------------

    \53\ ``Materially alter'' would mean potentially affecting or 
negating a compliance showing, impacting a certification assumption 
(e.g., design, human factors, operational training, etc.), or that 
would affect, or would have affected, the FAA's level of involvement 
(e.g., delegation decisions).
---------------------------------------------------------------------------

    The FAA proposes that the 90-day start date for this ongoing 
disclosure would logically follow the proposed deadline (within 90 
days) for the initial submittal of safety critical information by TC 
holders. The FAA also considers that 90 days would be sufficient time 
for transport category airplane TC holders to review their internal 
procedures and make any necessary revisions in order to facilitate the 
proposed ongoing disclosure requirements.

G. Interaction of This Proposal With Current Submittal and Disclosure 
Requirements

    As discussed in section B of this NPRM, TC and ODA holders 
currently submit certain information to the FAA, under the auspices of 
regulations such as Sec. Sec.  21.3 and 183.63. Some safety critical 
information is likely to also prompt reporting under those two 
regulations. However, under this proposal, a TC holder of an airplane 
covered under part 25 would not be relieved of any other reporting 
obligation such as those under Sec.  21.3, and an ODA holder similarly 
not relieved of any reporting obligation under part 183, as a result of 
the new obligation, which Congress required the FAA to mandate, to 
disclose safety critical information. Section 21.3 reports are, as 
reflected by their precise topics and accelerated timelines, urgent 
safety matters. Existing part 183 reporting may not characterize the 
safety critical information as clearly as is needed to implement this 
statutory mandate. However, the FAA requests comment on how these 
reporting processes might dovetail with this proposal, for greater 
efficiency in implementing the Congressional mandate.
    Existing Sec.  21.3(e) establishes timeframes for the required 
submittal of information under Sec.  21.3. Those timeframes are 
relatively short, due to the likely urgent safety implications of the 
information. Proposed Sec.  21.3(g) includes timelines appropriate to 
the submittal of safety critical information. Therefore, as part of the 
implementation of proposed Sec.  21.3(g), this NPRM proposes a minor 
revision of Sec.  21.3(e), to exclude the information that would be 
submitted as part of Sec.  21.3(g) from the requirements of paragraph 
(e), and to change the title of that section.

H. Explanations of Five Categories of Safety Critical Information

    Proposed Sec.  21.1(c) would contain the definitions of the five 
categories of safety critical information for the purposes of proposed 
Sec. Sec.  21.15(e) and (f), and 21.3(g). Each category of safety 
critical information that the FAA proposes, as required by Congress, to 
require to be submitted and subsequently disclosed by applicants in 
proposed Sec.  21.15(e) and (f), and by holders in proposed Sec.  
21.3(g), is explained as follows.
1. Uncommanded Operation of Safety Critical Functions and Features
    The first category of safety critical information that the FAA, 
pursuant to Congress' direction, would require applicants and holders 
to submit and disclose would be all design and operational details, 
intended functions, and failure modes of any system that, without being 
commanded by the flightcrew, commands the operation of any safety 
critical function or feature required for control of the airplane 
during flight or that otherwise changes the flight path or airspeed of 
an airplane.
    The FAA proposes that the regulatory definition of this category of 
information would be the same as the statutory definition, except for 
changing the opening ``Any'' to ``All'' to ensure that all, not just 
selected, information is provided, and making ``flight crew'' one word 
for consistency with other parts of 14 CFR.\54\ The FAA provides the 
following explanation of some of the terms in this category of safety 
critical information.
---------------------------------------------------------------------------

    \54\ The FAA's proposed definitions of safety critical 
information also include minor, nonsubstantive changes to facilitate 
regulatory implementation, such as replacing ``14 CFR'' with ``this 
chapter,'' etc.
---------------------------------------------------------------------------

    First, the ``system(s)'' which the FAA proposes would be covered by 
this requirement include, but are not limited to, flight control 
systems and other computer (software) controlled systems (e.g., 
autopilot, stability augmentation, automatic trim, autothrottle 
(autothrust), envelope protection), whose failure or erroneous 
activation would present a risk rated hazardous or catastrophic.
    A ``safety critical function or feature'' would be one whose 
failure could be hazardous or catastrophic. This would align with how 
the FAA has defined safety critical in other contexts, including 
transport category airplane SSA.\55\
---------------------------------------------------------------------------

    \55\ Per the ``Arsenal'' version of AC 25.1309-1A, Safety 
critical for transport category airplanes, means a function, 
component or system whose failure could be hazardous or 
catastrophic.
---------------------------------------------------------------------------

    Regarding ``all design and operational details,'' the FAA proposes 
that such details would be those with relevance to a referenced 
system's function, failure, or operational suitability. Under current 
practice, in order to show compliance with Sec. Sec.  25.1301(a) and 
25.1309(a), the submitted information would include sufficient design 
and operational detail, and description of the intended function, to 
enable the FAA to assess whether the equipment is of a kind and design 
appropriate to its intended function and performs its intended function 
under any operating condition. Section 25.1309(d) requires the 
applicant to submit an analysis of the possible modes of failure, 
probability of failures, resulting effects, etc., (i.e., a system 
safety assessment) to show

[[Page 4849]]

compliance to Sec.  25.1309(b).\56\ Thus, applicants for transport 
category airplane TCs covered under part 25 are already required to 
submit this information through the certification process.\57\
---------------------------------------------------------------------------

    \56\ 14 CFR 25.1309(b) establishes certain reliability 
requirements for airplane systems, equipment, and installations.
    \57\ Section 21.20 requires the applicant to show compliance 
with all applicable requirements, provide the FAA the means by which 
such compliance has been shown, and to certify such compliance.
---------------------------------------------------------------------------

    The FAA notes some overlap between this proposed category of 
information and the information that Sec.  21.3(c)(11) requires 
manufacturers to submit to the FAA: ``any . . . flight control 
malfunction, defect, or failure which causes an interference with 
normal control of the aircraft for which derogates the flying 
qualities.'' However, as previously discussed, any such overlap would 
not obviate the initial submittal and subsequent disclosure 
requirements that Congress directed the FAA to mandate, not only upon 
applicants, but also upon holders of transport category airplane TCs.
    The FAA anticipates that this category of safety critical 
information should not be overly difficult or time-consuming for 
holders to submit or continue to disclose. As previously noted, part 25 
transport category airplane TC holders will have disclosed much, if not 
all, of this information when seeking their original or amended TC. For 
example, much ``safety critical'' information would have been disclosed 
as part of showing of compliance with Sec.  25.1309, as described 
above.
2. Aspects of Autopilot and Autothrottle (Autothrust) Systems
    The next category of mandatory safety critical information that the 
FAA would require applicants and holders to submit and disclose would 
be all design and operational details, intended functions, failure 
modes, and mode annunciations of autopilot and autothrottle systems, if 
applicable.
    For purposes of this requirement, the term ``autopilot'' means a 
function that would provide automatic control of the airplane, 
typically in pitch, roll, and yaw. The term includes the sensors, 
computers, power supplies, servo-motors/actuators and associated 
wiring, necessary for its function. It includes any indications and 
controllers necessary for the pilot to manage and supervise the system. 
Any part of the autopilot system that remains connected to the primary 
flight controls when the autopilot is not in use is regarded as a part 
of the primary flight controls.\58\
---------------------------------------------------------------------------

    \58\ Reference AC 25.1329-1C, appendix B.
---------------------------------------------------------------------------

    For purposes of this requirement, the term ``autothrottle 
(autothrust)'' means a function that provides automatic control of the 
thrust of the airplane. The term includes the sensors, computers, power 
supplies, servo-motors/actuators and associated wiring, necessary for 
its function. It includes any indications and controllers necessary for 
the pilot to manage and supervise the system. Any part of the 
autothrust that remains connected to the engine controls when the 
autothrust is not in use is regarded as a part of the engine control 
system.
    For the purposes of this requirement, a ``mode annunciation'' is a 
function that provides the flightcrew with awareness of the current 
automation mode, alerts them of any mode changes or failures that could 
degrade the handling or operational characteristics of the airplane, 
and may require the flightcrew to alter their primary control strategy. 
The mode annunciation is included because it is imperative that the 
flightcrew understand the state of the airplane systems so they can 
interact with those systems appropriately as they fly the airplane. The 
FAA posits that Congress included mode annunciation in this category 
because it is imperative that the flightcrew understand the state of 
the airplane systems to minimize flightcrew errors and confusion 
concerning the behavior and operation of the flight guidance system as 
they fly the airplane.
    Although paragraph (B) of section 105(a) did not begin with the 
term ``any'' or ``all,'' the FAA is proposing that ``all'' such 
details, failure modes, etc., known to the applicant or holder would be 
required to be submitted and subsequently disclosed. This is to ensure 
that all, not just selected, applicable information is provided.
    Again, while there may be overlap with Sec.  21.3(c)(11), as 
discussed in section B of this NPRM, the FAA proposes that this would 
be an independent requirement.
    The FAA again anticipates that this information would not be overly 
difficult or time-consuming for applicants or holders to submit or 
disclose, because the compliance document(s) would have been submitted 
by the applicant as part of its showings of compliance and the company 
would be highlighting how the discovered information affects that prior 
showing of compliance with substantive regulations (for example, 
Sec. Sec.  25.1301(a) and 25.1309(a), (c), and (d) for certain 
equipment, systems, and installations; Sec.  25.1322 for flightcrew 
alerting; and certain paragraphs of Sec.  25.1329 for flight guidance 
systems).
3. Failures That Could Result in Hazardous or Catastrophic Outcomes
    The next category of safety critical information that the FAA 
proposes that applicants and holders be required to submit and continue 
to disclose, is all failure or operating conditions that the TC 
applicant or holder anticipates or has concluded would result in an 
outcome with a severity level of hazardous or catastrophic.
    As previously noted, current FAA guidance for applicants addresses 
catastrophic failure and operating conditions, but does not explicitly 
address ``hazardous'' conditions.\59\ However, as previously discussed, 
the ``Arsenal'' version of AC 25.1309-1A does so, and therefore 
applicants typically address hazardous failure and operating conditions 
in their SSAs.
---------------------------------------------------------------------------

    \59\ AC 25.1309-1A.
---------------------------------------------------------------------------

    ``Hazardous'' for purposes of this proposed rule would be the 
following:
    A failure condition that would reduce the capability of the 
airplane or the ability of the flightcrew to cope with adverse 
operating conditions to the extent that there would be--
    <bullet> A large reduction in safety margins or functional 
capabilities,
    <bullet> Physical distress or excessive workload such that the 
flightcrew cannot be relied upon to perform their tasks accurately or 
completely, or
    <bullet> Serious or fatal injuries to a relatively small number of 
persons other than the flightcrew.\60\
---------------------------------------------------------------------------

    \60\ For the purpose of performing a safety assessment, a 
``small number'' of fatal injuries means one such injury.
---------------------------------------------------------------------------

    ``Catastrophic'' for purposes of this rule would be a failure 
condition that would result in multiple fatalities, usually with the 
loss of the airplane.\61\
---------------------------------------------------------------------------

    \61\ A catastrophic failure condition was defined in previous 
versions of 14 CFR 25.1309, and is currently defined in AC 25.1309-
1A as a failure condition that would prevent continued safe flight 
and landing. Continued safe flight and landing was defined in AC 
25.1309-1A as: ``The capability for continued controlled flight and 
landing at a suitable airport, possibly using emergency procedures, 
but without requiring exceptional pilot skill or strength.'' Some 
airplane damage may be associated with a failure condition, during 
flight or upon landing.'' For the purpose of performing a safety 
assessment, ``multiple fatalities'' means two or more fatalities.
---------------------------------------------------------------------------

    The FAA anticipates that this category of safety critical 
information would not be overly difficult or time-consuming for 
applicants or holders to submit or disclose, for several reasons.
    First, applicants will submit, and all current TC holders would 
have submitted, during certification of

[[Page 4850]]

transport category airplanes with a certification basis after Amendment 
25-23,\62\ information about failure conditions that would result in 
outcomes with a severity level of major and catastrophic. New TC 
applicants include a functional hazard assessment as part of their 
compliance showings. The FAA anticipates that most if not all of the TC 
holders whose designs were approved using the ``Arsenal'' version of AC 
25.1309-1A as a means of compliance would not have to submit any new 
information here, unless a compliance assumption or determination has 
changed which materially alters that assessment. The ``major'' hazard 
category \63\ defined by AC 25.1309-1A is divided into two categories 
in the ``Arsenal'' version: ``hazardous'' and ``major,'' with 
corresponding probability requirements of ``extremely remote'' (on the 
order of 10<SUP>-</SUP>\9\ < p <= 10<SUP>-</SUP>\7\) and ``remote'' (on 
the order of 10<SUP>-</SUP>\7\ < p <= 10<SUP>-</SUP>\5\), respectively. 
The granular assessment of failure conditions in the ``Arsenal'' 
version allows for more accurate analysis of highly integrated systems, 
which perform complex and interrelated functions, particularly through 
the use of electronic technology and software-based techniques. This 
more granular categorization also allows for better differentiation of 
failure effects on flightcrew than the current requirements of Sec.  
25.1309(b). The ``hazardous'' category in the ``Arsenal'' version 
corresponds to the more severe end of the ``major'' category in current 
Sec.  25.1309(b)(2), which is referred to as ``severe major'' in AC 
25.1309-1A. Thus, the FAA is applying the ``Arsenal'' version of 
hazardous for this proposed rule.
---------------------------------------------------------------------------

    \62\ 35 FR 5665 (April 8, 1970), effective May 8, 1970.
    \63\ Reference AC 25.1309-1A, dated June 21, 1988.
---------------------------------------------------------------------------

    The FAA also notes that the requirement in section 105(a), and thus 
this NPRM, is intended to prompt the submittal, disclosure, and 
assessment of potential failure conditions that could have an outcome 
of hazardous or catastrophic. The FAA invites comment on this issue.
4. Software-Dependent Handling Qualities
    The fourth category of safety critical information that the FAA 
would require applicants and holders to submit and disclose would be 
any adverse handling quality that fails to meet the requirements of 
part 25 of this chapter without the addition of a software system to 
augment the flight controls of the airplane to produce compliant 
handling qualities.
    For purposes of this rulemaking, and consistent with FAA policy, an 
``adverse'' handling quality would be one that does not meet the 
applicable regulations on handling qualities in part 25. Some of the 
``applicable regulations'' for purposes of this requirement would be 
the Controllability and Maneuverability regulations in subpart B of 
part 25; Sec.  25.672, Stability augmentation \64\ and automatic and 
power-operated systems; and Sec.  25.1309(d), Equipment, systems, and 
installations. These sections include requirements to ensure the 
airplane is aerodynamically stable, and predictable in its handling. 
``Handling qualities'' as applied here is intended to address pilot in 
the loop control of the aircraft trajectory and thus includes 
assessment of those systems which rely, primarily, on pilot input to 
effect changes in that trajectory.
---------------------------------------------------------------------------

    \64\ Per AC 25.1329-1C, a ``Stability Augmentation System'' 
consists of automatic systems that provide or enhance stability for 
specific aerodynamic characteristics of an airplane (for example, 
yaw damper, longitudinal stability augmentation system, Mach trim).
---------------------------------------------------------------------------

    Examples of such ``software system(s)'' include MCAS on the Boeing 
737 MAX, pitch augmentation for the Boeing Model 777, and a flight 
control system that controls the yaw damper system of an airplane.
    The FAA notes the similarity of this provision of the proposed 
fourth category with the requirement of Sec.  21.3(c)(11), but again 
posits that it is sufficiently different that a separate requirement is 
necessary for holders, in order to comply with the statute.
    The FAA anticipates that this information would not be overly 
difficult or time-consuming for applicants or holders to submit or 
disclose, because by definition the system was required for the 
airplane to be compliant with FAA stability standards, and therefore 
would have been on the airplane's compliance documentation.
5. SSA for Components and Systems With Potentially Hazardous or 
Catastrophic Outcomes
    The fifth and final category of mandatory safety critical 
information that the FAA would require applicants and holders to submit 
and disclose would be a system safety assessment with respect to a 
system described in paragraph (1) or (2) of proposed Sec.  21.1(c), or 
with respect to any component or other system for which failure or 
erroneous operation of such component or system could result in an 
outcome with a severity level of hazardous or catastrophic.
    The FAA anticipates that previously-approved transport category 
airplane designs covered under part 25 will likely have this 
information in their SSAs, and that everything from a ``hazardous'' to 
a ``catastrophic'' failure condition would be included, and therefore 
not required to be resubmitted by a holder. Section 25.1309(d) requires 
all applicants for transport category airplane TCs to submit an 
analysis of the possible modes of failure, probability of failures, 
resulting effects (including effects of erroneous operation), etc., 
(i.e., an SSA) to show that proposed design's compliance to Sec.  
25.1309(b).
    The definitions of catastrophic and hazardous would be as 
previously noted. For purposes of proposed Sec.  21.3(g), applicants 
and holders could use the definitions in the ``Arsenal'' version of AC 
25.1309-1A, or in relevant FAA regulation or policy issued after the 
effective date of this proposed rule.

V. Regulatory Notices and Analyses

    Federal agencies consider impacts of regulatory actions under a 
variety of executive orders and other requirements. First, Executive 
Order 12866 and Executive Order 13563, as amended by Executive Order 
14094 (``Modernizing Regulatory Review''), direct that each Federal 
agency shall propose or adopt a regulation only upon a reasoned 
determination that the benefits of the intended regulation justify the 
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. 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 that 
may result in the expenditure by State, local, and Tribal governments, 
in the aggregate, or by the private sector, of $100,000,000 or more 
(adjusted annually for inflation) in any one year. The current 
threshold after adjustment for inflation is $177,000,000, using the 
most current (2022) Implicit Price Deflator for the Gross Domestic 
Product. This portion of the preamble summarizes the FAA's analysis of 
the economic impacts of this rule.

[[Page 4851]]

    In conducting these analyses, the FAA has determined that this 
rule: would result in minimal costs; is not a `significant regulatory 
action' as defined in section 3(f) of Executive Order 12866; will not 
have a significant economic impact on a substantial number of small 
entities; will not create unnecessary obstacles to the foreign commerce 
of the United States; and will not impose an unfunded mandate on State, 
local, or Tribal governments, or on the private sector.

A. Regulatory Impact Analysis

    This rule would implement a Congressional mandate by imposing new 
regulatory requirements (proposed Sec.  21.15(d), (e), and (f) for 
applicants for new and amended TCs and proposed Sec.  21.113(c)(1) 
through (c)(4) for applicants for new and amended STCs, and new 
regulatory requirements (proposed Sec.  21.3(g)(1) and (2)) for TC 
holders. This proposal would add definitions for safety critical 
information, in proposed Sec.  21.1(c).
    The following paragraphs describe the proposal, the baseline 
(current rule or current practice or current policy), and the costs/
benefits. The FAA expects the costs to be minimal as described below. 
Benefits are addressed qualitatively.
1. Applicants and Holders (Section 21.1(c)(1) Through (5))
    Proposal: As part of its implementation of the Congressional 
mandate related to safety critical information, the FAA would define 
five categories of safety critical information in proposed Sec.  
21.1(c)(1) through (5).
    Baseline: These five specific categories of safety critical 
information are not currently defined in FAA regulations.
    Costs/Benefits: This provision would impose no costs. These 
definitions of safety-critical information would facilitate the 
regulatory implementation of five categories of safety critical 
information in the Congressional mandate, and would inform applicants 
for, and holders of, TCs for transport airplanes covered under part 25 
regarding what must be submitted and disclosed under proposed 
Sec. Sec.  21.15(e), (f), and 21.3(g).
2. Applicants
a. Section 21.15(d)
    Proposal: An application for a TC, including a new or amended TC, 
would be required to be accompanied by a proposed certification plan.
    Baseline: Currently, applicants for TCs submit a proposed 
certification plan to the FAA at the time of application as indicated 
in FAA Order 8110.4C.
    Costs/Benefits: The FAA, as part of its implementation of the 
Congressional mandate, would establish a specific regulatory 
requirement for applicants to submit a certification plan. This would 
continue longstanding existing practices and thus involve minimal cost.
b. Section 21.15(d)(1)
    Proposal: The certification plan must include a proposed 
certification basis.
    Baseline: The proposed certification plan submitted by applicants 
under current practices includes a proposed certification basis, as 
described in FAA Order 8110.4C.\65\
---------------------------------------------------------------------------

    \65\ See footnote 15.
---------------------------------------------------------------------------

    Costs/Benefits: The proposal would implement part of the 
Congressional mandate and would incur minimal costs as the applicant 
already includes a proposed certification basis under the guidance in 
FAA Order 8110.4C.
c. Section 21.15(d)(2)
    Proposal: The applicant's proposed certification plan would be 
required to include a proposed compliance checklist that contains the 
means of compliance, and that identifies all deliverables that the 
applicant anticipates will be necessary to show compliance.
    Baseline: The proposed certification plan is submitted by 
applicants under current practices as described in FAA Order 8110.4C. 
Applicants submit a list of deliverables to show compliance with the 
applicable certification basis and how the applicant will ensure all 
showing have been made. This can be accomplished using a compliance 
checklist addressing each regulation applicable to the product. A 
description of how compliance will be shown (e.g., ground test, flight 
test, analysis, similarity, or other acceptable means of compliance) is 
also included in FAA Order 8110.4C as part of a certification plan.
    Costs/Benefits: The proposal would implement part of the 
Congressional mandate and would incur minimal costs as the applicant is 
already including a proposed compliance checklist with means of 
compliance identifying all known compliance deliverables that the 
applicant anticipates will be necessary to show compliance.
d. Section 21.15(d)(3)
    Proposal: The proposed certification plan would be required to 
include a proposed project schedule with proposed milestones.
    Baseline: Applicants for TCs include a proposed project schedule 
with proposed milestones in their certification plans as described in 
FAA Order 8110.4C.
    Costs/Benefits: The proposal would implement part of the 
Congressional mandate and incur minimal costs as the applicant is 
already including a proposed schedule with proposed milestones.
e. Section 21.15(d)(4)
    Proposal: The applicant's proposed certification plan would be 
required to include any other information necessary to allow the 
applicant's showings and certifying statement, and the FAA's findings, 
of compliance to be timely and accurately made.
    Baseline: Applicants for TCs and amended TCs submit proposed 
certification plans under the guidance in FAA Order 8110.4C \66\ that 
include any information necessary to allow the applicant's showings and 
certifying statement, and the FAA's findings, of compliance to be 
timely and accurately made.
---------------------------------------------------------------------------

    \66\ Paragraphs 2-3d.(1) through (11), as applicable to the 
certification project.
---------------------------------------------------------------------------

    Costs/Benefits: This rule would establish specific regulatory 
requirements for the information to be submitted in certification 
plans. These specific regulatory standards would be consistent with the 
informational and planning purposes of the categories of information 
typically submitted by applicants. Applicants could, and the FAA 
expects most applicants still would, use those existing categories as a 
means of compliance.
f. Section 21.15(d)(5)
    Proposal: An application for a new or amended, but not 
supplemental, TC for a transport category airplane would be required to 
include a proposed milestone that identifies the applicant's requested 
date for TC issuance.
    Baseline: Applicants for TCs include milestones in their 
certification plans that include the applicant's expected certification 
date as indicated in FAA Order 8110.4C.
    Costs/Benefits: Due to the alignment of the proposal with current 
practices, the FAA expects minimal costs.
g. Section 21.15(e)
    Proposal: For applicants for a new or amended, but not 
supplemental, type certificate for a transport category airplane, the 
proposed certification plan would be required to be updated to include 
or describe all of the safety critical information set forth in Sec.  
21.1(c).

[[Page 4852]]

The applicant would be required to submit this update to the FAA within 
1 year of submitting the application, but no later than 6 months prior 
to the requested date of issuance of the type certificate.
    Baseline: Applicants for transport category airplane TCs currently 
submit information describing their proposed design and operational 
details, means of showings of compliance and proposals for findings of 
compliance, in order to show that their proposed designs comply with 
several relevant regulations. Currently, applicants submit this 
compliance information throughout the certification process.
    Costs/Benefits: Safety critical information about its proposed 
design and operational suitability should already be available to the 
transport airplane applicant, even in preliminary form, at the time of 
submittal of the required update to the certification plan, so there 
should be no additional costs of identifying this information for 
submission. Submission costs should be negligible.
    The FAA would be more likely to receive safety critical information 
in a timely manner. The agency would also be more likely to receive 
safety critical information as the applicant would be aware of what 
information is considered safety critical due to the definitions in 
proposed Sec.  21.1(c).
    This could have a safety benefit because the agency would be aware 
of this important information relatively early in the certification 
process and would be more likely to receive specific safety critical 
information at that point. The FAA could then identify and provide 
feedback to the applicant about their proposed design and compliance 
information specific to safety critical information early.
h. Section 21.15(f)
    Proposal: Each applicant for a new or amended TC for a transport 
category airplane would, within 3 business days of discovery, be 
required to disclose to the FAA any information or design or analysis 
change that would materially alter any prior submission of the safety 
critical information defined in Sec.  21.1(c). The proposed rule would 
clearly define the FAA, not a designee, who would receive the safety 
critical information for transport category airplanes from applicants.
    Baseline: The transport category airplane applicant currently keeps 
its proposed design, operational, and compliance information updated 
throughout the project, but there is no specific timeframe for them to 
disclose new safety critical information to the FAA or for the types of 
changes that require disclosure. Under the current practice it can 
sometimes be a designee, or person within an ODA unit, who receives the 
updated information.
    Costs/Benefits: The FAA expects that the cost would be minimal 
because the applicant is currently expected to keep their information 
current. However, the rule would require the information or design or 
analysis change to be disclosed to the FAA within 3 business days of 
discovery. The FAA does not expect this prompt submission of the 
information to the FAA to be costly.
    This could have a safety benefit because the agency would be aware 
of changes to safety critical information earlier (within 3 business 
days of discovery). The FAA could then identify and share potential 
concerns about the changes with the applicant earlier, and resolve 
these concerns earlier.
    Also, there might be a benefit of submitting directly to the FAA, 
as it would be more likely that the appropriate information would get 
to the FAA. When investigating the FAA's certification of the Boeing 
737 MAX, a Congressional committee found that Boeing did not clearly 
relay important safety related information to the FAA because there was 
no requirement to do so.\67\ According to the committee report,\68\ 
this
---------------------------------------------------------------------------

    \67\ House Report at pg. 57.
    \68\ By quoting this report, the FAA is not taking a position on 
the causes or avoidance of the accidents, but simply noting what 
appears to have led to the legislation.

    ``. . . hinder[ed] a more comprehensive FAA review of the 737 
---------------------------------------------------------------------------
MAX which may have improved the safety of the airplane . . .''

i. Section 21.113(c)
    Proposal: Applications for new and amended STCs would, like 
applications for new and amended TCs, be required to be accompanied by 
a proposed certification plan.
    Baseline: Currently, applicants for STCs submit a proposed 
certification plan to the FAA at the time of application.
    Costs/Benefits: The proposal would incur minimal costs as STC 
applicants already submit proposed certification plans. The proposal 
would establish consistency in the requirements for TC and STC 
applicants by also adding the requirement for STC applicants and 
aligning the process for both certificate types.
j. Section 21.113(c)(1)
    Proposal: The certification plan must include a proposed 
certification basis.
    Baseline: The proposed certification plan submitted by applicants 
under current practices includes a proposed certification basis as 
described in FAA Order 8110.4C.
    Costs/Benefits: The proposal would establish consistency in the 
requirements for TC and STC applicants by aligning the process for both 
certificates and would incur minimal costs as the applicant is already 
including a proposed certification basis.
k. Section 21.113(c)(2)
    Proposal: The applicant's proposed certification plan would be 
required to include a proposed compliance checklist that contains means 
of compliance, and that identifies all deliverables that the applicant 
anticipates will be necessary to show compliance.
    Baseline: The proposed certification plan is submitted by 
applicants under current practices as described in FAA Order 8110.4C. 
Applicants submit a list of deliverables to show compliance with the 
applicable certification basis and to show how the applicant will 
ensure all showings have been made. This can be accomplished by using a 
compliance checklist that addresses each regulation applicable to the 
product. A description of how compliance will be shown (e.g., ground 
test, flight test, analysis, similarity, or other acceptable means of 
compliance) is also included in FAA Order 8110.4C as part of a 
certification plan.
    Costs/Benefits: The proposal would incur minimal costs as the 
applicant already includes a proposed compliance checklist that 
contains means of compliance, and that identifies all deliverables that 
the applicant anticipates will be necessary to show compliance. The 
proposal would establish consistency in the requirements for TC and STC 
applicants by also adding the requirement for STC applicants.
l. Section 21.113(c)(3)
    Proposal: The proposed certification plan would be required to 
include a proposed project schedule with proposed milestones.
    Baseline: Applicants for STCs include a proposed project schedule 
with proposed milestones in their certification plans as described in 
FAA Order 8110.4C.
    Costs/Benefits: The proposal would incur minimal costs as STC 
applicants are already submitting proposed milestones with their 
certification plans. The proposal would establish consistency in the 
requirements for TC and STC applicants by aligning the process for both 
certificate types.

[[Page 4853]]

m. Section 21.113(c)(4)
    Proposal: The certification plan for an STC would be required to 
include any other information necessary to allow the applicant's 
showings and certifying statement, and the FAA's findings, of 
compliance to be timely and accurately made.
    Baseline: Applicants for STCs submit proposed certification plans, 
that include under the guidance in FAA Order 8110.4C any information 
necessary to allow the applicant's showings, and the FAA's findings, of 
compliance to be timely and accurately made.
    Costs/Benefits: The proposal would incur minimal costs as STC 
applicants are already submitting proposed certification plans with 
information necessary to allow the applicant's showings, and the FAA's 
findings, of compliance to be timely and accurately made. The proposal 
would also establish consistency in the requirements for TC and STC 
applicants by also adding the requirement for STC applicants and 
aligning the process for both certificate types.
3. Holders
a. Section 21.3(g)(1)
    Proposal: The holder of a TC, including an amended TC but not 
including an STC, for a transport category airplane covered under part 
25 would, within 90 days of (effective date of final rule), be required 
to submit to the FAA, for each model, all safety critical information, 
as defined by Sec.  21.1(c), which is known and which has not 
previously been submitted to the FAA.
    Baseline: Holders of transport category airplane TCs are currently 
required to submit much of the safety critical information defined by 
Sec.  21.1(c) to the FAA. TC holders currently submit, or have already 
submitted, much of this information via a variety of regulatory and 
policy mechanisms. As an applicant, prior to receiving the transport 
category airplane TC, the holder would have had to have shown 
compliance with regulations such as Sec.  25.1309. Such compliance 
would have included compliance data which correlates with the five 
categories of safety critical information. Also, holders of such 
certificates have an ongoing regulatory obligation to inform the FAA of 
certain failures, malfunctions, and defects, including those that would 
affect the flight control system pursuant to Sec.  21.3(c)(11). The 
majority of current domestic holders of part 25 transport category 
airplane TCs are also ODA holders. Such ODA holders have an ongoing 
obligation to inform the FAA of potential safety and compliance issues 
with their approved designs, pursuant to Sec.  183.63.
    Cost/Benefits: The FAA expects minimal cost. First, the scope of 
the covered information is relatively narrow. Second, as described in 
the preceding paragraph, FAA expects that much if not all of such 
information will have already been submitted by the holder.
    The benefits of this requirement would be ensuring that the FAA 
would be aware of safety critical information, if any, that it had not 
previously been made aware of. This would be a potential safety benefit 
as the FAA would be able to identify and address any potential issues.
b. Section 21.3(g)(2)
    Proposal: The holder of a transport category airplane TC covered 
under part 25 would be required to disclose to the FAA, within 3 
business days of discovery, any newly discovered information or design 
or analysis change that would materially alter any safety critical 
information as defined by Sec.  21.1(c).
    Baseline: As described above, TC holders and ODA holders are 
required to submit certain information to the FAA on an ongoing basis. 
Some of this information, such as that required by Sec.  21.3, must 
generally be submitted within 24 hours. The timeline for submittal of 
other information is dependent on the nature of the information and the 
provisions of the ODA holder's FAA-approved ODA procedures manual. 
However, there is not a specific requirement to disclose safety 
critical information, as would be defined in proposed Sec.  21.1, 
within 3 business days.
    Costs/Benefits: Because, as described above, most of this 
information is already being updated (disclosed to the FAA) pursuant to 
existing processes, the FAA expects that this requirement, of 
disclosing information to the FAA within 3 days, will carry a minimal 
cost. The FAA expects that the provision would ensure that the safety 
critical information as specifically defined by Congress would be 
provided to the FAA in a timely manner.
    The FAA calls for comment on all the preceding determinations.
4. Conclusion
    Based on the preceding discussion, the FAA concludes that the 
proposed rule would impose minimal costs on industry, as discussed in 
the regulatory notices and analyses section. The FAA has found 
potential benefits from the proposal. The FAA may receive, and 
therefore be aware of, safety critical information that it had not 
previously been made aware of, not only from transport category 
airplane TC applicants but also from holders. It would receive the 
safety critical information earlier in, and more definitively 
throughout, the certification process. This could result in a safety 
benefit, as the FAA would be able to identify and share concerns with 
the applicant and address any potential issues. The proposed rule would 
codify the current practice of submitting a proposed certification plan 
with milestones, and thus provide a planning benefit, and increased 
certainty and predictability, for applicants. As it would follow 
current practice, this requirement would impose minimal cost. The 
regulatory implementation of the Congressional requirement that 
applicants and holders submit and disclose five categories of safety 
critical information would be another safety benefit. The submittal of 
previously undisclosed, and continued disclosure of newly discovered, 
safety critical information by transport category airplane TC holders 
may also provide a safety benefit.

B. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) of 1980, Public Law 96-354, 94 
Stat. 1164 (5 U.S.C. 601-612), as amended by the Small Business 
Regulatory Enforcement Fairness Act of 1996 (Pub. L. 104-121, 110 Stat. 
857, Mar. 29, 1996) and the Small Business Jobs Act of 2010 (Pub. L. 
111-240, 124 Stat. 2504 Sept. 27, 2010), requires Federal agencies to 
consider the effects of the regulatory action on small business and 
other small entities and to minimize any significant economic impact. 
The term ``small entities'' comprises small businesses and not-for-
profit organizations that are independently owned and operated and are 
not dominant in their fields, and governmental jurisdictions with 
populations of less than 50,000.
    The FAA has determined that, based on the Small Business 
Administration (SBA) size standard for aircraft manufacturing, (Table 
1), none of the entities that would be subject to the proposed 
rulemaking are small entities. Also, as described in the RIA, the 
proposed rule would impose minimal costs. Therefore, the FAA proposes 
to certify that the rule would not have a significant economic impact 
on a substantial number of small entities. The FAA welcomes comments on 
the basis for this certification.

[[Page 4854]]



                  Table 1--Small Business Size Standard
------------------------------------------------------------------------
         NAICS code                Description          Size standard
------------------------------------------------------------------------
336411......................  Aircraft              1,500 employees.
                               manufacturing.
------------------------------------------------------------------------
Source: SBA (2019) \69\.
NAICS = North American Industrial Classification System.

C. International Trade Impact Assessment
---------------------------------------------------------------------------

    \69\ Small Business Administration (SBA). 2019. Table of Size 
Standards. Effective August 12, 2019. www.sba.gov/document/support-table-size-standards.
---------------------------------------------------------------------------

    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 rule and 
determined that as it results in a minimal cost to U.S. manufacturers, 
it would not create an unnecessary obstacle to foreign commerce. As a 
result, the FAA does not consider this rule as creating an unnecessary 
obstacle to foreign commerce.

D. Unfunded Mandates Assessment

    The Unfunded Mandates Reform Act of 1995 (2 U.S.C. 1531-1538) 
governs the issuance of Federal regulations that require unfunded 
mandates. An unfunded mandate is a regulation that requires a State, 
local, or Tribal government or the private sector to incur direct costs 
without the Federal government having first provided the funds to pay 
those costs. The FAA determined that the proposed rule would not result 
in the expenditure of $177,000,000 or more by State, local, or Tribal 
governments, in the aggregate, or the private sector, in any one year.

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 the proposed requirement for transport category airplane TC 
applicants and holders to submit and disclose safety critical 
information because this information is already submitted under 
existing processes, as described elsewhere in this NPRM. Approval to 
collect such information under those processes was previously approved 
by the Office of Management and Budget (OMB) under the provisions of 
the Paperwork Reduction Act of 1995 (44 U.S.C. 3507(d)) and was 
assigned OMB Control Number 2120-0018.

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 (NEPA) in the absence of extraordinary circumstances. The FAA has 
determined this rulemaking action qualifies for the categorical 
exclusion identified in paragraph 5-6.6f for regulations and involves 
no extraordinary circumstances.

VI. Executive Order Determinations

A. Executive Order 13132, Federalism

    The FAA has analyzed this proposed rule under the principles and 
criteria of Executive Order (E.O.) 13132, Federalism. The FAA 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 13175, Consultation and Coordination With Indian 
Tribal Governments

    Consistent with Executive Order 13175, Consultation and 
Coordination with Indian Tribal Governments,\70\ and FAA Order 1210.20, 
American Indian and Alaska Native Tribal Consultation Policy and 
Procedures,\71\ the FAA ensures that Federally Recognized Tribes 
(Tribes) are given the opportunity to provide meaningful and timely 
input regarding proposed Federal actions that have the potential to 
affect uniquely or significantly their respective Tribes. At this 
point, the FAA has not identified any unique or significant effects, 
environmental or otherwise, on Tribes resulting from this proposed 
rule.
---------------------------------------------------------------------------

    \70\ 65 FR 67249 (Nov. 6, 2000).
    \71\ FAA Order No. 1210.20 (Jan. 28, 2004), available at 
www.faa.gov/documentLibrary/media/1210.pdf.
---------------------------------------------------------------------------

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

    The FAA analyzed this proposed rule under E.O. 13211, Actions 
Concerning Regulations that Significantly Affect Energy Supply, 
Distribution, or Use (May 18, 2001). The FAA 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.

D. Executive Order 13609, Promoting International Regulatory 
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 
E.O. 13609 and has determined that this action would have no effect on 
international regulatory cooperation.

[[Page 4855]]

VII. Additional Information

A. Comments Invited

    The FAA invites interested persons to participate in this 
rulemaking by submitting written comments, data, or views. The FAA 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 submit only one time if comments 
are filed electronically, or commenters should send only one copy of 
written comments if comments are filed in writing.
    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 FAA may change this proposal in light 
of the comments it receives.
    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.

B. Confidential Business Information

    Confidential Business Information (CBI) is commercial or financial 
information that is both customarily and actually treated as private by 
its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), 
CBI is exempt from public disclosure. If your comments responsive to 
this NPRM contain commercial or financial information that is 
customarily treated as private, that you actually treat as private, and 
that is relevant or responsive to this NPRM, it is important that you 
clearly designate the submitted comments as CBI. Please mark each page 
of your submission containing CBI as ``PROPIN.'' The FAA will treat 
such marked submissions as confidential under the FOIA, and they will 
not be placed in the public docket of this NPRM. Submissions containing 
CBI should be sent to the person in the FOR FURTHER INFORMATION CONTACT 
section of this document. Any commentary that the FAA receives which is 
not specifically designated as CBI will be placed in the public docket 
for this rulemaking.

C. Electronic Access and Filing

    A copy of this NPRM, all comments received, any final rule, and all 
background material may be viewed online at www.regulations.gov using 
the docket number listed above. A copy of this proposed rule will be 
placed in the docket. Electronic retrieval help and guidelines are 
available on the website. It is available 24 hours each day, 365 days 
each year. An electronic copy of this document may also be downloaded 
from the Office of the Federal Register's website at 
www.federalregister.gov and the Government Publishing Office's website 
at www.govinfo.gov. A copy may also be found at the FAA's Regulations 
and Policies website at www.faa.gov/regulations_policies.
    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) 267-9677. 
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 in 
the electronic docket for this rulemaking.

D. Small Business Regulatory Enforcement Fairness Act

    The Small Business Regulatory Enforcement Fairness Act (SBREFA) of 
1996 requires the 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 
www.faa.gov/regulations_policies/rulemaking/sbre_act/.

List of Subjects in 14 CFR Part 21

    Aircraft, Aviation safety, Exports, Imports, 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 21--CERTIFICATION PROCEDURES FOR PRODUCTS AND ARTICLES

0
1. The authority citation for part 21 continues to read as follows:

    Authority:  42 U.S.C. 7572; 49 U.S.C. 106(f), 106(g), 40105, 
40113, 44701-44702, 44704, 44707, 44709, 44711, 44713, 44715, 45303.

0
2. Amend Sec.  21.1 by adding paragraph (c) to read as follows:


Sec.  21.1  Applicability and definitions.

* * * * *
    (c) For purposes of Sec. Sec.  21.3 and 21.15, safety critical 
information is:
    (1) All design and operational details, intended functions, and 
failure modes of any system that, without being commanded by the 
flightcrew, commands the operation of any safety critical function or 
feature required for control of the airplane during flight or that 
otherwise changes the flight path or airspeed of an airplane;
    (2) all design and operational details, intended functions, failure 
modes, and mode annunciations of autopilot and autothrottle systems, if 
applicable;
    (3) all failure or operating conditions that the type certificate 
applicant or holder anticipates or has concluded would result in an 
outcome with a severity level of hazardous or catastrophic;
    (4) any adverse handling quality that fails to meet the 
requirements of part 25 of this chapter without the addition of a 
software system to augment the flight controls of the airplane to 
produce compliant handling qualities; and
    (5) a system safety assessment with respect to a system described 
in paragraph (1) or (2) of this paragraph, or with respect to any 
component or other system for which failure or erroneous operation of 
such component or system could result in an outcome with a severity 
level of hazardous or catastrophic.
0
3. Amend Sec.  21.3 by revising the section heading and the 
introductory text of paragraph (e), and adding paragraph (g) to read as 
follows:


Sec.  21.3  Reporting of failures, malfunctions, defects, and safety 
critical information.

* * * * *
    (e) Each report required by this section, except as provided in 
Sec.  21.3(g)--
* * * * *
    (g) The holder of a type certificate, including an amended type 
certificate but not including a supplemental type

[[Page 4856]]

certificate, for a transport category airplane covered under part 25 of 
this chapter must:
    (1) Within 90 days of [date 60 days after publication of final rule 
in the Federal Register], submit to the FAA, for each model, all safety 
critical information, as defined by Sec.  21.1(c), which is known and 
which has not previously been submitted to the FAA, and;
    (2) After 90 days of [date 60 days after publication of final rule 
in the Federal Register], disclose to the FAA, within 3 business days 
of discovery, any newly discovered safety critical information as 
defined by Sec.  21.1(c), or design or analysis change that would 
materially alter such information.
0
4. Amend Sec.  21.15 by adding paragraphs (d), (e), and (f) to read as 
follows:


Sec.  21.15  Application for type certificate.

* * * * *
    (d) An application for a type certificate, including a new or 
amended type certificate, must be accompanied by a proposed 
certification plan. The certification plan must include:
    (1) A proposed certification basis;
    (2) A proposed compliance checklist that contains means of 
compliance, and that identifies all deliverables that the applicant 
anticipates will be necessary to show compliance;
    (3) A proposed project schedule, with milestones;
    (4) Any other information necessary to allow the applicant's 
showings and certifying statement, and the FAA's findings, of 
compliance to be timely and accurately made; and
    (5) For applications for a new or amended, but not supplemental, 
type certificate for a transport category airplane, a proposed 
milestone that identifies the applicant's requested date for type 
certificate issuance.
    (e) Within 1 year of submitting the application for a new or 
amended, but not supplemental, type certificate for a transport 
category airplane, but no later than 6 months prior to the requested 
date of issuance of the type certificate, the applicant must update the 
proposed certification plan required by Sec.  21.15(d) to include or 
describe all of the safety critical information set forth in Sec.  
21.1(c).
    (f) Each applicant for a new or amended, but not supplemental, type 
certificate for a transport category airplane must, within 3 business 
days of discovery, disclose to the FAA any information or design or 
analysis change that would materially alter any prior submission of the 
safety critical information set forth in Sec.  21.1(c).
0
5. Amend Sec.  21.113 by revising paragraph (c) and adding paragraphs 
(c)(1) through (c)(4) to read as follows:


Sec.  21.113  Requirement for supplemental type certificate.

* * * * *
    (c) The application for an STC must be made in the form and manner 
prescribed by the FAA and must be accompanied by a proposed 
certification plan. The certification plan must include:
    (1) A proposed certification basis;
    (2) A proposed compliance checklist that contains means of 
compliance, and that identifies all deliverables that the applicant 
anticipates will be necessary to show compliance;
    (3) A proposed project schedule, with milestones; and
    (4) Any other information necessary to allow the applicant's 
showings and certifying statement, and the FAA's findings, of 
compliance to be timely and accurately made.

    Issued under authority provided by 49 U.S.C. 106(f), 44701, and 
44704 in Washington, DC, on January 22, 2024.
Lirio Liu,
Executive Director of Aircraft Certification.
[FR Doc. 2024-01485 Filed 1-24-24; 8:45 am]
BILLING CODE 4910-13-P


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