Back to publication catalog

Published 2021-04-20 · Federal Register document 2021-08055

Airworthiness Directives; The Boeing Company Airplanes

Publication summary

The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC- 10-30F (KC-10A and KDC-10), DC-10-40 and DC-10-40F airplanes; and Model MD-10-10F and MD-10-30F airplanes. This AD was prompted by a report that an operator found a crack in the upper flange of the pylon aft bulkhead bracket. This AD requires a general visual inspection of the left and right wing pylon at the aft bulkhead bracket for any lockbolt and collar; repetitive surface and open hole eddy current high frequency (ETHF) inspections of the left and right wing pylon at the aft bulkhead bracket for any cracking; and applicable on-condition actions. The FAA is issuing this AD to address the unsafe condition on these products.

Why this record is shown

Source: Federal Register annual FAA metadata. Acquired 2026-09-03T22:24:08.106391+00:00. The title, summary and date are source facts.

Source revision
federal_register_ad_metadata_2021-9c919420683447c6
Source row
results[127]
Raw source SHA-256
9c919420683447c683ad0c877cb886e341c11862be32b47c536a001b1d76dcb5

Final-rule publication

Recorded publication clauses

AD identifier printed in this edition
2021-08-10
Effective date printed in this edition
2021-05-25
Read 11 complete recorded clauses
Effective Date
(a) Effective Date

    This airworthiness directive (AD) is effective May 25, 2021.

Exact source excerpt. Text positions 10018–10104, end exclusive, in the original decoded publication. SHA-256: c00a2759d8be66edafc69220605953d6b4be4edd8ff8241629133c0e8f5e0c21

Affected ADs
(b) Affected ADs

    None.

Exact source excerpt. Text positions 10104–10133, end exclusive, in the original decoded publication. SHA-256: 871a4afc60ceeae06e8010585055188633d616078500c45937092bfe892239c0

Applicability wording · Applicability
(c) Applicability

    This AD applies to all The Boeing Company airplanes specified in 
paragraphs (c)(1) through (5) of this AD, certificated in any 
category.
    (1) Model DC-10-10 and DC-10-10F airplanes.
    (2) Model DC-10-15 airplanes.
    (3) Model DC-10-30 and DC-10-30F (KC-10A and KDC-10) airplanes.
    (4) Model DC-10-40 and DC-10-40F airplanes.
    (5) Model MD-10-10F and MD-10-30F airplanes.

Exact source excerpt. Text positions 10133–10543, end exclusive, in the original decoded publication. SHA-256: 290e6bebd35204860545e01290af96f3b2e82a3302674fa2c7f6ac67f71ec5bb

Subject
(d) Subject

    Air Transport Association (ATA) of America Code 54, Nacelles/
pylons.

Exact source excerpt. Text positions 10543–10631, end exclusive, in the original decoded publication. SHA-256: 965d2e1891bda21636b3e8a29c4a3b1fe986ee773e61af574cd84217708deb41

Unsafe Condition
(e) Unsafe Condition

    This AD was prompted by a report that an operator found a crack 
in the upper flange of the pylon aft bulkhead bracket. The FAA is 
issuing this AD to address possible cracking of the wing pylon at 
the aft bulkhead bracket, which could result in the inability of the 
pylon to sustain limit load and adversely affect the structural 
integrity of the airplane.

Exact source excerpt. Text positions 10631–11019, end exclusive, in the original decoded publication. SHA-256: 8ece1d6f819815d1cfd25f6ff11c2c98752c29fb31be9d14baf878208fe23216

Compliance
(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

Exact source excerpt. Text positions 11019–11121, end exclusive, in the original decoded publication. SHA-256: 00fbfa31932483f627d0ce0a11cbd2e35e15d9231842b91ac85623ce533912d3

Required Actions
(g) Required Actions

    Except as specified by paragraph (h) of this AD: At the 
applicable times specified in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin DC10-54A111 RB, dated June 26, 2020, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
DC10-54A111 RB, dated June 26, 2020.

    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
DC10-54A111, dated June 26, 2020, which is referred to in Boeing 
Alert Requirements Bulletin DC10-54A111 RB, dated June 26, 2020.

Exact source excerpt. Text positions 11121–11783, end exclusive, in the original decoded publication. SHA-256: 0b4268b826cd5f72b56efcc92e265f034cc563a77cf87284565e1a86629eb4fd

Exceptions to Service Information Specifications
(h) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Requirements Bulletin DC10-54A111 RB, 
dated June 26, 2020, uses the phrase ``the original issue date of 
Requirements Bulletin DC10-54A111 RB,'' this AD requires using ``the 
effective date of this AD.''
    (2) Where Boeing Alert Requirements Bulletin DC10-54A111 RB, 
dated June 26, 2020, specifies contacting Boeing for repair, 
modification, or replacement instructions: This AD requires doing 
the repair, modification, or replacement using a method approved in 
accordance with the procedures specified in paragraph (i) of this 
AD.

Exact source excerpt. Text positions 11783–12405, end exclusive, in the original decoded publication. SHA-256: e711bc74ad035318fbb0e291690895f8e1a10d20a0d9789c00724c70c0077de4

Alternative Methods of Compliance (AMOCs)
(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles ACO Branch, FAA, has the authority 
to approve AMOCs for this AD, if requested using the procedures 
found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your 
request to your principal inspector or responsible Flight Standards 
Office, as appropriate. If sending information directly to the 
manager of the certification office, send it to the attention of the 
person identified in paragraph (j)(1) of this AD. Information may be 
emailed to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the responsible Flight Standards Office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair, modification, or alteration required by this AD 
if it is approved by The Boeing Company Organization Designation 
Authorization (ODA) that has been authorized by the Manager, Los 
Angeles ACO Branch, FAA, to make those findings. To be approved, the 
repair method, modification deviation, or alteration deviation must 
meet the certification basis of the airplane, and the approval must 
specifically refer to this AD.

Exact source excerpt. Text positions 12405–13644, end exclusive, in the original decoded publication. SHA-256: 89c1fc26d70ffdc768986273151d95e36e78a0c982633056713f0e69e0b53f95

Related Information
(j) Related Information

    (1) For more information about this AD, contact Manuel 
Hernandez, Aerospace Engineer, Airframe Section, FAA, Los Angeles 
ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; 
phone: 562-627-5256; fax: 562-627-5210; email: 
[email protected].
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (k)(3) and (4) of this AD.

Exact source excerpt. Text positions 13644–14099, end exclusive, in the original decoded publication. SHA-256: 37a373976df1855c34ef4ce137e7bde352a3ca166acaaaaec7c7f09a3094ef65

Material Incorporated by Reference
(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Alert Requirements Bulletin DC10-54A111 RB, dated 
June 26, 2020.
    (ii) [Reserved]
    (3) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Contractual & Data Services 
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-
5600; telephone 562-797-1717; internet https://www.myboeingfleet.com.
    (4) You may view this service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 2200 
South 216th St., Des Moines, WA. For information on the

[[Page 20451]]

availability of this material at the FAA, call 206-231-3195.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

Exact source excerpt. Text positions 14099–15396, end exclusive, in the original decoded publication. SHA-256: 914c653cdcc6e8b944423c5da45b7699702fc39a3ef2771e5c8982df7a337fca

No replacement link has been established from this edition. The complete historical rule chain and current legal effect remain unknown.

Find all recorded historical references to AD 2021-08-10 · 0 printed reference observations in this pinned collection.

These are observations from one dated publication. Current legal status is unknown; aircraft applicability, installed configuration, compliance and burden require separate evidence. Missing or unparsed conditions remain unknown.

Why these observations are shown

They were extracted offline from the same immutable official HTML source as the complete recorded text. The dated source wording, original text coordinates and exact quote digests are retained. PDF/text agreement and current regulatory effect have not been qualified.

Observation revision: whole-ad-publication-clause-observations-1.0.1. Text SHA-256: 7476e9becd1b5c113c11e38115366d7d3cfa48fa08b43162cef771ccfad90f3b. Source manifest: 37195f1d970a9855abc2947f0fc6aaf1b60de7007e2eaf03868f397d76b99574.

Official source · 2021-04-20

Publication text

This is the complete recorded text of this dated publication.

Current legal effect is unknown. Aircraft applicability, installed configuration and compliance require separate evidence. PDF/text agreement has not been evaluated.

Read the complete official publication text
[Federal Register Volume 86, Number 74 (Tuesday, April 20, 2021)]
[Rules and Regulations]
[Pages 20448-20451]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-08055]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-1167; Project Identifier AD-2020-01007-T; 
Amendment 39-21504; AD 2021-08-10]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
The Boeing Company Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-
10-30F (KC-10A and KDC-10), DC-10-40

[[Page 20449]]

and DC-10-40F airplanes; and Model MD-10-10F and MD-10-30F airplanes. 
This AD was prompted by a report that an operator found a crack in the 
upper flange of the pylon aft bulkhead bracket. This AD requires a 
general visual inspection of the left and right wing pylon at the aft 
bulkhead bracket for any lockbolt and collar; repetitive surface and 
open hole eddy current high frequency (ETHF) inspections of the left 
and right wing pylon at the aft bulkhead bracket for any cracking; and 
applicable on-condition actions. The FAA is issuing this AD to address 
the unsafe condition on these products.

DATES: This AD is effective May 25, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of May 25, 
2021.

ADDRESSES: For service information identified in this final rule, 
contact Boeing Commercial Airplanes, Attention: Contractual & Data 
Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 
90740-5600; telephone 562-797-1717; internet https://www.myboeingfleet.com. You may view this service information at the 
FAA, Airworthiness Products Section, Operational Safety Branch, 2200 
South 216th St., Des Moines, WA. For information on the availability of 
this material at the FAA, call 206-231-3195. It is also available at 
https://www.regulations.gov by searching for and locating Docket No. 
FAA-2020-1167.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2020-1167; or in person at 
Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The AD docket contains this final rule, any 
comments received, and other information. The address for Docket 
Operations is U.S. Department of Transportation, Docket Operations, M-
30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue 
SE, Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Manuel Hernandez, Aerospace Engineer, 
Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount 
Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5256; fax: 562-627-
5210; email: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to all The Boeing Company 
Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and 
KDC-10), DC-10-40 and DC-10-40F airplanes; and Model MD-10-10F and MD-
10-30F airplanes. The NPRM published in the Federal Register on January 
15, 2021 (86 FR 3885). The NPRM was prompted by a report that an 
operator found a crack in the upper flange of the pylon aft bulkhead 
bracket. In the NPRM, the FAA proposed to require a general visual 
inspection of the left and right wing pylon at the aft bulkhead bracket 
for any lockbolt and collar; repetitive surface and open hole ETHF 
inspections of the left and right wing pylon at the aft bulkhead 
bracket for any cracking; and applicable on-condition actions. The FAA 
is issuing this AD to address possible cracking of the wing pylon at 
the aft bulkhead bracket, which could result in the inability of the 
pylon to sustain limit load and adversely affect the structural 
integrity of the airplane.

Discussion of Final Airworthiness Directive

Comments

    The FAA received a comment from The Air Line Pilots Association, 
International (ALPA) who supported the NPRM without change.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Except for minor editorial changes, this AD is adopted as 
proposed in the NPRM. None of the changes will increase the economic 
burden on any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin DC10-54A111 RB, 
dated June 26, 2020. The service information describes procedures for a 
general visual inspection of the left and right wing pylon at the aft 
bulkhead bracket for any lockbolt and collar; repetitive surface and 
open hole ETHF inspections of the left and right wing pylon at the aft 
bulkhead bracket for any cracking; and applicable on-condition actions. 
On-condition actions include modifying any aft bulkhead bracket that 
has a lockbolt and collar, and repair or replacement of the aft 
bulkhead bracket.
    This service information is reasonably available because the 
interested parties have access to it through their normal course of 
business or by the means identified in ADDRESSES.

Costs of Compliance

    The FAA estimates that this AD affects 103 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                      Estimated Costs for Required Actions
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                     Labor cost          Parts cost     Cost per product        operators
----------------------------------------------------------------------------------------------------------------
General visual inspection......  2 work-hours x $85 per               $0  $170..............  $17,510.
                                  hour = $170.
Surface and open hole ETHF       5 work-hours x $85 per                0  $425 per            $8,755 per
 inspections.                     hour = $425 per                          inspection cycle.   inspection cycle.
                                  inspection cycle.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary on-
condition modifications that would be required. The FAA has no way of 
determining the number of aircraft that might need these on-condition 
modifications:

                                     Estimated Costs of On-Condition Actions
----------------------------------------------------------------------------------------------------------------
             Labor cost                            Parts cost                         Cost per product
----------------------------------------------------------------------------------------------------------------
1 work-hour x $85 per hour = $85     $100 per lockbolt/collar.............  $185 per lockbolt/collar.
 per lockbolt/collar (maximum of 8
 lockbolt/collars).
----------------------------------------------------------------------------------------------------------------


[[Page 20450]]

    The FAA has received no definitive data on which to base the cost 
estimates for the on-condition repairs and replacements specified in 
this AD.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    The FAA is issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: General requirements. 
Under that section, Congress charges the FAA with promoting safe flight 
of civil aircraft in air commerce by prescribing regulations for 
practices, methods, and procedures the Administrator finds necessary 
for safety in air commerce. This regulation is within the scope of that 
authority because it addresses an unsafe condition that is likely to 
exist or develop on products identified in this rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

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


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2021-08-10 The Boeing Company: Amendment 39-21504; Docket No. FAA-
2020-1167; Project Identifier AD-2020-01007-T.

(a) Effective Date

    This airworthiness directive (AD) is effective May 25, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company airplanes specified in 
paragraphs (c)(1) through (5) of this AD, certificated in any 
category.
    (1) Model DC-10-10 and DC-10-10F airplanes.
    (2) Model DC-10-15 airplanes.
    (3) Model DC-10-30 and DC-10-30F (KC-10A and KDC-10) airplanes.
    (4) Model DC-10-40 and DC-10-40F airplanes.
    (5) Model MD-10-10F and MD-10-30F airplanes.

(d) Subject

    Air Transport Association (ATA) of America Code 54, Nacelles/
pylons.

(e) Unsafe Condition

    This AD was prompted by a report that an operator found a crack 
in the upper flange of the pylon aft bulkhead bracket. The FAA is 
issuing this AD to address possible cracking of the wing pylon at 
the aft bulkhead bracket, which could result in the inability of the 
pylon to sustain limit load and adversely affect the structural 
integrity of the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    Except as specified by paragraph (h) of this AD: At the 
applicable times specified in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin DC10-54A111 RB, dated June 26, 2020, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
DC10-54A111 RB, dated June 26, 2020.

    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
DC10-54A111, dated June 26, 2020, which is referred to in Boeing 
Alert Requirements Bulletin DC10-54A111 RB, dated June 26, 2020.

(h) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Requirements Bulletin DC10-54A111 RB, 
dated June 26, 2020, uses the phrase ``the original issue date of 
Requirements Bulletin DC10-54A111 RB,'' this AD requires using ``the 
effective date of this AD.''
    (2) Where Boeing Alert Requirements Bulletin DC10-54A111 RB, 
dated June 26, 2020, specifies contacting Boeing for repair, 
modification, or replacement instructions: This AD requires doing 
the repair, modification, or replacement using a method approved in 
accordance with the procedures specified in paragraph (i) of this 
AD.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles ACO Branch, FAA, has the authority 
to approve AMOCs for this AD, if requested using the procedures 
found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your 
request to your principal inspector or responsible Flight Standards 
Office, as appropriate. If sending information directly to the 
manager of the certification office, send it to the attention of the 
person identified in paragraph (j)(1) of this AD. Information may be 
emailed to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the responsible Flight Standards Office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair, modification, or alteration required by this AD 
if it is approved by The Boeing Company Organization Designation 
Authorization (ODA) that has been authorized by the Manager, Los 
Angeles ACO Branch, FAA, to make those findings. To be approved, the 
repair method, modification deviation, or alteration deviation must 
meet the certification basis of the airplane, and the approval must 
specifically refer to this AD.

(j) Related Information

    (1) For more information about this AD, contact Manuel 
Hernandez, Aerospace Engineer, Airframe Section, FAA, Los Angeles 
ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; 
phone: 562-627-5256; fax: 562-627-5210; email: 
[email protected].
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (k)(3) and (4) of this AD.

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Alert Requirements Bulletin DC10-54A111 RB, dated 
June 26, 2020.
    (ii) [Reserved]
    (3) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Contractual & Data Services 
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-
5600; telephone 562-797-1717; internet https://www.myboeingfleet.com.
    (4) You may view this service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 2200 
South 216th St., Des Moines, WA. For information on the

[[Page 20451]]

availability of this material at the FAA, call 206-231-3195.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on April 1, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-08055 Filed 4-19-21; 8:45 am]
BILLING CODE 4910-13-P


Why this text is shown

The complete text was extracted from the official GovInfo HTML edition for this publication. Acquired 2026-10-09T01:52:02.454575+00:00. Text extraction preserves the recorded source wording; it does not determine current requirements.

Open the captured official edition

Source SHA-256
c7c3295bb1529dfed16a4f0f1d861fc500b34b95a3619d013c944fa6c0b04d4d
Text SHA-256
7476e9becd1b5c113c11e38115366d7d3cfa48fa08b43162cef771ccfad90f3b

Return to the full metadata catalog · Search complete publication text · Explore retained publication text and evidence

Coverage and limits

These are dated publication metadata, recorded clauses and literal source observations. Word, model-label, header and reference matches do not establish current legal effect, manufacturer/model identity, aircraft applicability, installed configuration or compliance.

The collection uses 33 explicit annual source snapshots. Source captures and operative-text qualifications have separate states. Missing information remains unknown.