[Federal Register Volume 86, Number 191 (Wednesday, October 6, 2021)]
[Proposed Rules]
[Pages 55538-55542]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-21787]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0664; Project Identifier AD-2021-00158-T]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain The Boeing Company Model 787-8, 787-9, and 787-10 
airplanes. This proposed AD was prompted by significant changes, 
including new or more restrictive requirements, made to the 
airworthiness limitations (AWLs) related to fuel tank ignition 
prevention and the nitrogen generation system. This proposed AD would 
require revising the existing maintenance or inspection program, as 
applicable, to incorporate new or more restrictive airworthiness 
limitations. The FAA is proposing this AD to address the unsafe 
condition on these products.

DATES: The FAA must receive comments on this proposed AD by November 
22, 2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, 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.

[[Page 55539]]

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0664; 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 NPRM, any comments 
received, and other information. The street address for Docket 
Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Tak Kobayashi, Aerospace Engineer, 
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA; phone: 206-231-3553; email: [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2021-0664; Project Identifier 
AD-2021-00158-T'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. The FAA 
will consider all comments received by the closing date and may amend 
this proposal because of those comments.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, to 
https://www.regulations.gov, including any personal information you 
provide. The agency will also post a report summarizing each 
substantive verbal contact received about this NPRM.

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 Tak 
Kobayashi, Aerospace Engineer, Propulsion Section, FAA, Seattle ACO 
Branch, 2200 South 216th St., Des Moines, WA; phone: 206-231-3553; 
email: [email protected]. Any commentary that the FAA receives 
which is not specifically designated as CBI will be placed in the 
public docket for this rulemaking.

Background

    The FAA has assessed the changes, including new or more restrictive 
requirements, that have been made to the AWLs related to fuel tank 
ignition prevention and the nitrogen generation system. The FAA is 
issuing this AD to address ignition sources inside the fuel tanks and 
increased flammability exposure of the fuel tanks caused by latent 
failures, alterations, repairs, or maintenance actions, which could 
result in a fuel tank explosion and consequent loss of an airplane.
    The FAA issued AD 2018-11-13, Amendment 39-19301 (83 FR 25894, June 
5, 2018) (AD 2018-11-13), which applies to certain The Boeing Company 
Model 787-8 airplanes. AD 2018-11-13 requires, among other things, 
revising the inspection or maintenance program to incorporate an AWL. 
Since the FAA issued AD 2018-11-13, AWL No. 57-AWL-13, ``Inspection 
Requirements for In-Tank Fasteners and Edge Seal near Disbond 
Arrestment (DBA) Fastener Installations in Lightning Zone 2,'' has not 
been revised, therefore, this proposed AD would require the 
incorporation of AWL No. 57-AWL-13 that is also mandated by AD 2018-11-
13. Incorporating the revision required by this proposed AD would 
terminate the requirements of paragraph (h) of AD 2018-11-13 for 
certain Model 787-8 airplanes only.

Airworthiness Limitations Based on Type Design

    When a type certificate is issued for a type design, the 
Airworthiness Limitations section (ALS) of the Instructions for 
Continued Airworthiness, including its revision level, is part of that 
type design, as specified in 14 CFR 21.31(c). U.S. operators must 
operate their airplanes in an airworthy condition, in accordance with 
14 CFR 91.7(a). Included in this obligation is the requirement to 
perform any maintenance or inspections specified in the ALS, and in 
accordance with the ALS as specified in 14 CFR 43.16 and 91.403(c), 
unless an alternative has been approved by the FAA.
    The sum effect of these requirements is an obligation to comply 
with the ALS revision defined in the type design referenced in the 
manufacturer's conformity statement. Therefore, operators are required 
to maintain each airplane in accordance with the ALS revision that has 
been approved as part of the type design for that airplane. Operators 
are allowed to step up and comply with a ``later'' ALS revision 
published after the ``type design'' ALS revision. However, compliance 
with a later ALS revision is not a mandatory requirement.
    This proposed AD applies to certain Model 787 airplanes. For those 
affected airplanes, this proposed AD would require revising the 
maintenance or inspection program by incorporating the information 
specified in the August 2018 revision of the Model 787 ALS and thereby, 
would mandate the ALS revision in the proposed AD.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing 787 Special Compliance Items/Airworthiness 
Limitations, D011Z009-03-04, dated August 2018. This service 
information specifies AWLs that include airworthiness limitation 
instructions (ALIs) and critical design configuration control 
limitations (CDCCLs) related to fuel tank ignition prevention and the 
nitrogen generation system.
    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.

Proposed AD Requirements in This NPRM

    This proposed AD would require revising the existing maintenance or 
inspection program, as applicable, to incorporate new or more 
restrictive AWLs.
    This proposed AD would also require revisions to certain operator 
maintenance documents to include new actions (e.g., inspections) and 
CDCCLs. Compliance with these actions is required by 14 CFR 91.403(c). 
For airplanes that have been previously modified, altered, or repaired 
in the areas addressed by this proposed AD, the operator may not be 
able to accomplish the actions described in the revisions. In this 
situation, to comply with 14 CFR 91.403(c), the operator must request 
approval for an alternative

[[Page 55540]]

method of compliance according to paragraph (j) of this proposed AD.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 121 airplanes of U.S. registry. The FAA estimates the following 
costs to comply with this proposed AD:
    The FAA has determined that revising the existing maintenance or 
inspection program takes an average of 90 work-hours per operator, 
although the agency recognizes that this number may vary from operator 
to operator. Since operators incorporate maintenance or inspection 
program changes for their affected fleet(s), the FAA has determined 
that a per-operator estimate is more accurate than a per-airplane 
estimate. Therefore, the FAA estimates the average total cost per 
operator to be $7,650 (90 work-hours x $85 per work-hour).

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

    The FAA determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Would not affect intrastate aviation in Alaska, and
    (3) Would 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 Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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:

The Boeing Company: Docket No. FAA-2021-0664; Project Identifier AD-
2021-00158-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by November 22, 2021.

(b) Affected ADs

    This AD affects AD 2018-11-13, Amendment 39-19301 (83 FR 25894, 
June 5, 2018) (AD 2018-11-13).

(c) Applicability

    This AD applies to The Boeing Company Model 787-8, 787-9, and 
787-10 airplanes, certificated in any category, having line numbers 
(L/Ns) 1 through 871 inclusive, excluding L/N 688; and L/Ns 873, 
875, 877, 878, 879, 881, and 883.

(d) Subject

    Air Transport Association (ATA) of America Code 28, Fuel.

(e) Unsafe Condition

    This AD was prompted by significant changes, including new and 
more restrictive requirements, made to the airworthiness limitations 
(AWLs) related to fuel tank ignition prevention and the nitrogen 
generation system. The FAA is issuing this AD to address ignition 
sources inside the fuel tanks and increased flammability exposure of 
the fuel tanks caused by latent failures, alterations, repairs, or 
maintenance actions, which could result in a fuel tank explosion and 
consequent loss of an airplane.

(f) Compliance

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

(g) Maintenance or Inspection Program Revision

    Within 180 days after the effective date of this AD, revise the 
existing maintenance or inspection program, as applicable, to 
incorporate the information specified in Sections C through F of 
Boeing 787 Special Compliance Items/Airworthiness Limitations, 
D011Z009-03-04, dated August 2018. The initial compliance time for 
doing the airworthiness limitation instruction (ALI) tasks is at the 
times specified in paragraphs (g)(1) through (14) of this AD.
    (1) For airworthiness limitation (AWL) No. 28-AWL-89, ``Fuel 
Quantity Data Concentrator (FQDC) Bracket Inspections,'' at the 
applicable time in paragraph (g)(1)(i) or (ii) of this AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 28-AWL-89: Within 5 years or 10,000 flight 
cycles, whichever occur first after the most recent inspection was 
performed as specified in AWL No. 28-AWL-89.
    (ii) For airplanes on which no initial inspection was performed: 
Within 5 years or 10,000 flight cycles, whichever occurs first after 
the date of issuance of the original standard airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness.
    (2) For AWL No. 57-AWL-01, ``Edge and Fillet Seals at Stringer 
and Spar Locations (Zone 2),'' at the applicable time in paragraph 
(g)(2)(i) or (ii) of this AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 57-AWL-01: Within 12 years or 24,000 flight 
cycles, whichever occurs first after the most recent inspection was 
performed as specified in AWL No. 57-AWL-01.
    (ii) For airplanes on which no initial inspection was performed: 
Within 12 years or 24,000 flight cycles, whichever occurs first 
after the date of issuance of the original standard airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness.
    (3) For AWL No. 57-AWL-02, ``Fasteners on Bare Carbon Fiber 
Reinforced Plastic (CFRP) Stripes,'' at the applicable time in 
paragraph (g)(3)(i) or (ii) of this AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 57-AWL-02: Within 12 years or 24,000 flight 
cycles, whichever occurs first after the most recent inspection was 
performed as specified in AWL No. 57-AWL-02.
    (ii) For airplanes on which no initial inspection was performed: 
Within 12 years or 24,000 flight cycles, whichever occurs first 
after the date of issuance of the original standard airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness.
    (4) For AWL No. 57-AWL-03, ``Head-in-tank Thin-Sleeved 
Interference-Fit Fasteners with Heads in the Fuel Tank'' at the 
applicable time in paragraph (g)(4)(i) or (ii) of this AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 57-AWL-03: Within 12 years or 24,000 flight 
cycles, whichever occurs first after the most recent inspection was 
performed as specified in AWL No. 57-AWL-03.
    (ii) For airplanes on which no initial inspection was performed: 
Within 12 years or 24,000 flight cycles, whichever occurs first 
after the date of issuance of the original

[[Page 55541]]

standard airworthiness certificate or the date of issuance of the 
original export certificate of airworthiness.
    (5) For AWL No. 57-AWL-05, ``Titanium Collars--BACC30CT 
Fasteners (Clearance Fit).'' at the applicable time in paragraph 
(g)(5)(i) or (ii) of this AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 57-AWL-05: Within 12 years or 24,000 flight 
cycles, whichever occurs first after the most recent inspection was 
performed as specified in AWL No. 57-AWL-05.
    (ii) For airplanes on which no initial inspection was performed: 
Within 12 years or 24,000 flight cycles, whichever occurs first 
after the date of issuance of the original standard airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness.
    (6) For AWL No. 57-AWL-06, ``Titanium Collars--BACC30CY Collars 
(Interference-Fit with Swaged Collars)'' at the applicable time in 
paragraph (g)(6)(i) or (ii) of this AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 57-AWL-06: Within 12 years or 24,000 flight 
cycles, whichever occurs first after the most recent inspection was 
performed as specified in AWL No. 57-AWL-06.
    (ii) For airplanes on which no initial inspection was performed: 
Within 12 years or 24,000 flight cycles, whichever occurs first 
after the date of issuance of the original standard airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness.
    (7) For AWL No. 57-AWL-07, ``Tension-rated Bolt Locations at 
Side of Body (SOB) and Nacelle Fittings'' at the applicable time in 
paragraph (g)(7)(i) or (ii) of this AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 57-AWL-07: Within 12 years or 24,000 flight 
cycles, whichever occurs first after the most recent inspection was 
performed as specified in AWL No. 57-AWL-07.
    (ii) For airplanes on which no initial inspection was performed: 
Within 12 years or 24,000 flight cycles, whichever occurs first 
after the date of issuance of the original standard airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness.
    (8) For AWL No. 57-AWL-08, ``Dielectric Top on Wing Surface,'' 
at the applicable time in paragraph (g)(8)(i) or (ii) of this AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 57-AWL-08: Within 6 years or 12,000 flight 
cycles, whichever occurs first after the most recent inspection was 
performed as specified in AWL No. 57-AWL-08.
    (ii) For airplanes on which no initial inspection was performed: 
Within 6 years or 12,000 flight cycles, whichever occurs first after 
the date of issuance of the original standard airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness.
    (9) For AWL No. 57-AWL-09, ``Inspection Requirements for Class 
1A Seal Installations created as a result of Boeing Material Review 
Board,'' at the applicable time in paragraph (g)(9)(i) or (ii) of 
this AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 57-AWL-09: Within 12 years or 24,000 flight 
cycles, whichever occurs first after the most recent inspection was 
performed as specified in AWL No. 57-AWL-09.
    (ii) For airplanes on which no initial inspection was performed: 
Within 12 years or 24,000 flight cycles, whichever occurs first 
after the date of issuance of the original standard airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness.
    (10) For AWL No. 57-AWL-10, ``Inspection Requirements for In-
Tank Fasteners near Side of Body (SOB) Rib and between Ribs 7 and 
18,'' at the applicable time in paragraph (g)(10)(i) or (ii) of this 
AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 57-AWL-10: Within 12 years or 24,000 flight 
cycles, whichever occurs first after the most recent inspection was 
performed as specified in AWL No. 57-AWL-10.
    (ii) For airplanes on which no initial inspection was performed: 
Within 12 years or 24,000 flight cycles, whichever occurs first 
after the date of issuance of the original standard airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness.
    (11) For AWL No. 57-AWL-13, ``Inspection Requirements for In-
Tank Fasteners and Edge Seal near Disbond Arrestment (DBA) Fastener 
Installations in Lightning Zone 2,'' at the applicable time in 
paragraph (g)(11)(i) or (ii) of this AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 57-AWL-13: Within 12 years or 24,000 flight 
cycles, whichever occurs first after the most recent inspection was 
performed as specified in AWL No. 57-AWL-13.
    (ii) For airplanes on which no initial inspection was performed: 
At the applicable time in paragraph (g)(11)(ii)(A) or (B) of this 
AD.
    (A) For airplanes on which Boeing Service Bulletin B787-81205-
SB570030-00 is applicable: Within 12 years or 24,000 flight cycles, 
whichever occurs first after the incorporation of Boeing Service 
Bulletin B787-81205-SB570030-00.
    (B) For airplanes on which Boeing Service Bulletin B787-81205-
SB570030-00 is not applicable: Within 12 years or 24,000 flight 
cycles, whichever occurs first after the date of issuance of the 
original standard airworthiness certificate or the date of issuance 
of the original export certificate of airworthiness.
    (12) For AWL No. 57-AWL-14, ``Supplemental Inspection 
Requirements for Pre-cured Sealant Caps, Fillet Seals, and Edge 
Seals associated Stringer Splice Fitting Installation located at 
Right Wing Upper Panel Stringer No.3, just Outboard of the Side of 
Body Rib,'' at the applicable time in paragraph (g)(12)(i) or (ii) 
of this AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 57-AWL-14: Within 12 years or 24,000 flight 
cycles whichever occurs first after the most recent inspection was 
performed as specified in AWL No. 57-AWL-14.
    (ii) For airplanes on which no initial inspection was performed: 
Within 12 years or 24,000 flight cycles, whichever occurs first 
after the date of issuance of the original standard airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness.
    (13) For AWL No. 57-AWL-15, ``Inspection Requirements for Pre-
cured Sealant Caps, Injection Seals, Fillet Seals, and Edge Seals 
associated with the Wing Lower Panel Stringer Attachments to the 
Lower Side of Body (SOB) Chord,'' at the applicable time in 
paragraph (g)(13)(i) or (ii) of this AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 57-AWL-15: Within 12 years or 24,000 flight 
cycles, whichever occurs first after the most recent inspection was 
performed as specified in AWL No. 57-AWL-15.
    (ii) For airplanes on which no initial inspection was performed: 
Within 12 years or 24,000 flight cycles, whichever occurs first 
after the date of issuance of the original standard airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness.
    (14) For AWL No. 57-AWL-16, ``Supplemental Inspection 
Requirements for Edge Seals located at Left Wing Upper Panel 
Stringer No. 19, Between Ribs 8 and 9,'' at the applicable time in 
paragraph (g)(14)(i) or (ii) of this AD.
    (i) For airplanes on which an inspection was performed as 
specified in AWL No. 57-AWL-16: Within 12 years or 24,000 flight 
cycles, whichever occurs first after the most recent inspection was 
performed as specified in AWL No. 57-AWL-16.
    (ii) For airplanes on which no initial inspection was performed: 
Within 12 years or 24,000 flight cycles, whichever occurs first 
after the date of issuance of the original standard airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness.

(h) No Alternative Actions, Intervals, or CDCCLs

    After the existing maintenance or inspection program has been 
revised as required by paragraph (g) of this AD, no alternative 
actions (e.g., inspections), intervals, or CDCCLs may be used unless 
the actions, intervals, and CDCCLs are approved as an alternative 
method of compliance (AMOC) in accordance with the procedures 
specified in paragraph (j) of this AD.

(i) Terminating Actions

    Accomplishment of the revision required by paragraph (g) of this 
AD terminates the requirements specified in paragraph (h) of AD 
2018-11-13, for Model 787-8 airplanes only.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle 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 Related Information.

[[Page 55542]]

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, Seattle 
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.

(k) Related Information

    (1) For more information about this AD, contact Tak Kobayashi, 
Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 
2200 South 216th St., Des Moines, WA; phone: 206-231-3553; email: 
[email protected].
    (2) 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. You may view this referenced 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.

    Issued on August 7, 2021.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2021-21787 Filed 10-5-21; 8:45 am]
BILLING CODE 4910-13-P