[Federal Register Volume 86, Number 57 (Friday, March 26, 2021)]
[Proposed Rules]
[Pages 16133-16137]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-06022]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0134; Project Identifier AD-2020-01254-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 777 airplanes. This proposed AD 
was prompted by significant changes, including new or more restrictive 
requirements, made to the airworthiness limitations (AWLs) and Critical 
Design Configuration Control Limitations (CDCCLs) related to fuel tank 
ignition prevention, the engine fuel suction feed system, 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 May 10, 
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.

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-
0134; 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: Kevin Nguyen, Aerospace Engineer, 
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3555; email: 
kevin.nguyen@faa.gov.

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-2021-0134; Project Identifier 
AD AD-2020-01254-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 the 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 proposed AD.

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

[[Page 16134]]

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 Kevin Nguyen, Aerospace Engineer, Propulsion Section, 
FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; 
phone and fax: 206-231-3555; email: kevin.nguyen@faa.gov. 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 examined the underlying safety issues involved in fuel 
tank explosions on several large transport airplanes, including the 
adequacy of existing regulations, the service history of airplanes 
subject to those regulations, and existing maintenance practices for 
fuel tank systems. As a result of those findings, the FAA issued a 
final rule titled ``Transport Airplane Fuel Tank System Design Review, 
Flammability Reduction, and Maintenance and Inspection Requirements'' 
(66 FR 23086, May 7, 2001). In addition to new airworthiness standards 
for transport airplanes and new maintenance requirements that rule 
included Amendment 21-78, which established Special Federal Aviation 
Regulation No. 88 (``SFAR 88'') to 14 CFR part 21. Subsequently, SFAR 
88 was amended by: Amendment 21-82 (67 FR 57490, September 10, 2002; 
corrected at 67 FR 70809, November 26, 2002), Amendment 21-83 (67 FR 
72830, December 9, 2002; corrected at 68 FR 37735, June 25, 2003, to 
change ``21-82'' to ``21-83''), and Amendment 21-101 (83 FR 9162, March 
5, 2018).
    Among other actions, SFAR 88 requires certain type design (i.e., 
type certificate (TC) and supplemental type certificate (STC)) holders 
to substantiate that their fuel tank systems can prevent ignition 
sources in the fuel tanks. This requirement applies to type design 
holders for large turbine-powered transport airplanes and for 
subsequent modifications to those airplanes. It requires them to 
perform design reviews and to develop design changes and maintenance 
procedures if their designs do not meet the new fuel tank safety 
standards. As explained in the preamble to the final rule published on 
May 7, 2001, the FAA intended to adopt airworthiness directives to 
mandate any changes found necessary to address unsafe conditions 
identified as a result of these reviews.
    In evaluating these design reviews, the FAA has established four 
criteria intended to define the unsafe conditions associated with fuel 
tank systems that require corrective actions. The percentage of 
operating time during which fuel tanks are exposed to flammable 
conditions is one of these criteria. The other three criteria address 
the failure types under evaluation: Single failures, single failures in 
combination with another latent condition(s), and in-service failure 
experience. For all four criteria, the evaluations included 
consideration of previous actions taken that may mitigate the need for 
further action.
    The FAA issued AD 2008-11-13, Amendment 39-15536 (73 FR 30737, May 
29, 2008) (AD 2008-11-13), which applies to certain The Boeing Company 
Model 777-200, -200LR, -300, and -300ER series airplanes. The 
applicability of AD 2008-11-13 did not include the Boeing Company Model 
777F series airplane because those airplanes were not yet type 
certificated. AD 2008-11-13 requires incorporation of fuel system AWLs 
and also requires an initial inspection to phase in certain repetitive 
inspections, and repair if necessary. The fuel system AWLs were 
developed to satisfy SFAR 88 requirements and were included in the 
Airworthiness Limitations Section (ALS) of the manufacturer's 
Instructions for Continued Airworthiness. Since the FAA issued AD 2008-
11-13, the ALS has been significantly revised by the manufacturer to 
correct technical and editorial errors and also to add new or more 
restrictive requirements. Many of those changes are related to fuel 
tank ignition prevention, the engine fuel suction feed system, and the 
nitrogen generation system. The FAA has determined that the specific 
revisions of the AWL mandated by AD 2008-11-13 (which applies to 
airplanes with an original standard airworthiness certificate or 
original export certificate of airworthiness issued before December 5, 
2007) and the revisions of the AWL that have been delivered with 
airplanes as part of the type design and airworthiness certificate on 
or after December 5, 2007, are inadequate to provide information 
necessary to maintain critical design features and perform inspections.
    The FAA also issued AD 2014-09-09, Amendment 39-17844 (79 FR 30005, 
May 27, 2014) (AD 2014-09-09), which applies to all The Boeing Company 
Model 777-200, -200LR, -300, -300ER, and 777F series airplanes. AD 
2014-09-09 requires revising the maintenance program to incorporate a 
revision to the Airworthiness Limitations Section of the maintenance 
planning data (MPD) document. Since the FAA issued AD 2014-09-09, 28-
AWL-101 has been revised, therefore, this proposed AD would require the 
incorporation of the revised 28-AWL-101. Incorporating the revision 
required by this proposed AD would terminate all the requirements of AD 
2014-09-09.
    The FAA has received a report indicating that significant changes, 
including new or more restrictive requirements, made to the AWLs and 
CDCCLs related to fuel tank ignition prevention, the engine fuel 
suction feed system, and the nitrogen generation system. The FAA is 
issuing this AD to address ignition sources inside the fuel tanks and 
the increased flammability exposure of the center fuel tank caused by 
latent failures, alterations, repairs, or maintenance actions, which 
could result in a fuel tank explosion and consequent loss of an 
airplane; and to address potential loss of engine fuel suction feed 
capability, which could result in dual engine flameouts, inability to 
restart engines, and consequent forced landing of the airplane.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Section 9, Airworthiness Limitations (AWLs) and 
Certification Maintenance Requirements (CMRs), of Boeing 777-200/200LR/
300/300ER/777F Maintenance Planning Data (MPD) Document, D622W001-9, 
dated November 2019. This service information describes airworthiness 
limitations and CDCCLs tasks related to fuel tank ignition prevention, 
the engine fuel suction feed system, 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 the ADDRESSES section.

FAA's Determination

    The FAA is proposing this AD because the agency evaluated all the 
relevant information and determined the unsafe condition described 
previously is likely to exist or develop in other products of the same 
type design.

Proposed AD Requirements

    This proposed AD would require revising the existing maintenance or 
inspection program, as applicable, to incorporate new or more 
restrictive airworthiness limitations.
    This proposed AD would require revisions to certain operator 
maintenance documents to include new actions (e.g., inspections) and 
CDCCLs. Compliance with these actions and CDCCLs is required by 14 CFR

[[Page 16135]]

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

Differences Between This Proposed AD and the Service Information

    Paragraph (g) of this proposed AD would require operators to revise 
their existing maintenance or inspection program by incorporating, in 
part, AWL No. 28-AWL-11, ``Fuel Quantity Indicating System (FQIS) and 
Auxiliary Fuel Tank (Cell) Electronic Fuel Level Indication System 
(EFLI)--Out Tank Wiring Installation Separation Requirement,'' of 
Section 9, Airworthiness Limitations (AWLs) and Certification 
Maintenance Requirements (CMRs), of Boeing 777-200/200LR/300/300ER/777F 
Maintenance Planning Data (MPD) Document, D622W001-9, dated November 
2019.
    Paragraph (h) of this proposed AD would allow certain changes to be 
made to the requirements specified in AWL No. 28-AWL-11 as an option. 
Where AWL No. 28-AWL-11 identifies certain wire types for routing and 
installation of any new wiring under certain conditions, paragraph (h) 
of this proposed AD provides acceptable alternative wire types. 
Additionally, where AWL No. 28-AWL-11 identifies certain wiring sleeve 
material for new wiring installed under certain conditions, paragraph 
(h) of this proposed AD provides acceptable alternative wire sleeve 
materials.

Alternative Methods of Compliance (AMOCs) Previously Approved for AD 
2008-11-13

    The FAA has previously issued AMOC approvals for compliance with 
paragraph (g)(2) of AD 2008-11-13 to allow operators to incorporate 
alternative versions of AWL No. 28-AWL-11. AWL No. 28-AWL-11 includes 
the requirements for new wiring introduced by any alterations or 
changes to the type design, including STC modifications, in proximity 
to wiring that penetrates the fuel tank wall. Certain STCs that 
introduced new wiring near the fuel quantity indicating system (FQIS) 
wiring utilized design features that were different from the critical 
design features for fuel tank ignition prevention specified in the AD-
mandated version of AWL No. 28-AWL-11. For those STCs, the FAA has 
approved alternative versions of AWL No. 28-AWL-11 that specified 
critical design features associated with STC modifications. The FAA has 
determined that certain critical design features specified in the AMOC-
approved versions of AWL No. 28-AWL-11 are not acceptable to meet the 
intent of this AWL. Therefore, this proposed AD does not allow credit 
for AMOCs previously approved under AD 2008-11-13. However, based on 
the agency's assessment of critical design features, the FAA has 
provided options under paragraph (h) of this proposed AD to allow 
certain changes to be made to the requirements specified in AWL No. 28-
AWL-11.
    The requirements for new wiring versus existing wiring are 
specified in AWL No. 28-AWL-11. Based on these requirements, any STC 
modifications that are installed after the incorporation of the version 
of AWL No. 28-AWL-11 required by paragraph (g) of this proposed AD must 
comply with AWL No. 28-AWL-11, including any mandatory rework, or the 
operator must request approval of an AMOC according to paragraph (k) of 
this proposed AD. Any STC modifications that are installed prior to the 
incorporation of the version of AWL No. 28 AWL-11 required by paragraph 
(g) of this proposed AD are not required to be reworked for compliance 
with the new wiring requirements of AWL No. 28-AWL-11, except that 
future repair and replacement of existing wiring must follow AWL No. 
28-AWL-11.

Costs of Compliance

    The FAA estimates that this proposed AD affects 219 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-2021-0134; Project Identifier AD-
2020-01254-T.

[[Page 16136]]

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) action by May 10, 2021.

(b) Affected ADs

    This AD affects the ADs specified in paragraphs (b)(1) and (2) 
of this AD.
    (1) AD 2008-11-13, Amendment 39-15536 (73 FR 30737, May 29, 
2008) (AD 2008-11-13).
    (2) AD 2014-09-09, Amendment 39-17844 (79 FR 30005, May 27, 
2014) (AD 2014-09-09).

(c) Applicability

    This AD applies to The Boeing Company Model 777-200, -200LR, -
300, -300ER, and 777F series airplanes having line numbers (L/Ns) 1 
through 1609 inclusive, certificated in any category.

(d) Subject

    Air Transport Association (ATA) of America Code 28, Fuel; 47, 
Inert Gas System.

(e) Unsafe Condition

    This AD was prompted by significant changes, including new or 
more restrictive requirements, made to the airworthiness limitations 
(AWLs) and Critical Design Configuration Control Limitations 
(CDCCLs) related to fuel tank ignition prevention, the engine fuel 
suction feed system, and the nitrogen generation system. The FAA is 
issuing this AD to address ignition sources inside the fuel tanks 
and the increased flammability exposure of the center fuel tank 
caused by latent failures, alterations, repairs, or maintenance 
actions, which could result in a fuel tank explosion and consequent 
loss of an airplane; and to address potential loss of engine fuel 
suction feed capability, which could result in dual engine 
flameouts, inability to restart engines, and consequent forced 
landing of the airplane.

(f) Compliance

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

(g) Maintenance or Inspection Program Revision

    Within 60 days after the effective date of this AD, revise the 
existing maintenance or inspection program, as applicable, to 
incorporate the information in Section D, ``Airworthiness 
Limitations--Systems,'' including Subsections D.1, D.2, and D.3, of 
Section 9, Airworthiness Limitations (AWLs) and Certification 
Maintenance Requirements (CMRs), of Boeing 777-200/200LR/300/300ER/
777F Maintenance Planning Data (MPD) Document, D622W001-9, dated 
November 2019; except as provided by paragraph (h) of this AD. The 
initial compliance time for doing the airworthiness limitation 
instructions (ALI) tasks is at the times specified in paragraphs 
(g)(1) through (10) of this AD.
    (1) For AWL 28-AWL-01, ``External Wires Over Center Fuel Tank'': 
Within 16,000 flight cycles or 3,000 days, whichever occurs first 
after the date of issuance of the original airworthiness certificate 
or the date of issuance of the original export certificate of 
airworthiness; or within 16,000 flight cycles or 3,000 days, 
whichever occurs first after the most recent inspection was 
performed as specified in 28-AWL-01; whichever occurs later.
    (2) For AWL 28-AWL-03, ``Fuel Quantity Indicating System 
(FQIS)--Out of Tank Wiring Lightning Shield to Ground Termination'': 
Within 16,000 flight cycles or 3,000 days, whichever occurs first 
after the date of issuance of the original airworthiness certificate 
or the date of issuance of the original export certificate of 
airworthiness; or within 16,000 flight cycles or 3,000 days, 
whichever occurs first after the most recent inspection was 
performed as specified in 28-AWL-03; whichever occurs later.
    (3) For AWL 28-AWL-18, ``Over-Current and Arcing Protection 
Electrical Design Features Operation--AC Fuel Pump GFI and GFP'': 
Within 375 days after the date of issuance of the original 
airworthiness certificate or the date of issuance of the original 
export certificate of airworthiness; or within 375 days after 
accomplishment of the actions specified in Boeing Service Bulletin 
777-28A0037; or within 375 days after accomplishment of the actions 
specified in Boeing Service Bulletin 777-28A0038; or within 375 days 
after the most recent inspection was performed as specified in 28-
AWL-18; whichever occurs latest.
    (4) For AWL 28-AWL-21, ``External Wires Over Auxiliary Fuel Tank 
(Cell)'': Within 16,000 flight cycles or 3,000 days, whichever 
occurs first after the date of issuance of the original 
airworthiness certificate or date of issuance of the original export 
certificate of airworthiness; or within 16,000 flight cycles or 
3,000 days, whichever occurs first after the most recent inspection 
was performed as specified in 28-AWL-21; or within 365 days after 
the effective date of this AD; whichever occurs latest.
    (5) For AWL 28-AWL-26, ``Auxiliary Fuel Tank (Cell) AC Fuel Pump 
Uncommanded ON/Automatic Shutoff Circuit'': Within 375 days after 
the date of issuance of the original airworthiness certificate or 
the date of issuance of the original export certificate of 
airworthiness; or within 375 days after the most recent inspection 
was performed as specified in 28-AWL-26; or within 30 days after the 
effective date of this AD; whichever occurs latest.
    (6) For AWL 28-AWL-32, ``Cushion Clamps and Teflon Sleeving 
Installed on Out-of-Tank Wire Bundles Installed on Brackets that are 
Mounted Directly on the Fuel Tanks'': For airplanes having L/N 1 
through 503 inclusive, within 3,750 days after accomplishment of the 
actions specified in Boeing Service Bulletins 777-57A0050, or within 
60 months after the effective date of this AD, whichever occurs 
later. For airplanes having L/N 504 and subsequent, within 3,750 
days after the date of issuance of the original airworthiness 
certificate or the date of issuance of the original export 
certificate of airworthiness; or within 60 months after the 
effective date of this AD; whichever occurs later.
    (7) For AWL 28-AWL-101, ``Engine Fuel Suction Feed Operational 
Test'': Within 7,500 flight hours after the date of issuance of the 
original airworthiness certificate or the date of issuance of the 
original export certificate of airworthiness; or within 7,500 flight 
hours after the most recent inspection was performed as specified in 
AWL No. 28-AWL-101; whichever occurs later.
    (8) For AWL 47-AWL-04, ``NGS--Thermal Switch'': Within 108,000 
flight hours after the date of issuance of the original 
airworthiness certificate or the date of issuance of the original 
export certificate of airworthiness; or within 108,000 flight hours 
after accomplishment of the actions specified in Boeing Service 
Bulletin 777-47-0002; or within 108,000 flight hours after the most 
recent inspection was performed as specified in 47-AWL-04; whichever 
occurs latest.
    (9) For 47-AWL-05, ``NGS--Cross Vent Check Valve'': Within 
10,682 flight hours after the date of issuance of the original 
airworthiness certificate or the date of issuance of the original 
export certificate of airworthiness; or within 10,682 flight hours 
after accomplishment of the actions specified in Boeing Service 
Bulletin 777-47-0002; or within 10,682 flight hours after the most 
recent inspection was performed as specified in 47-AWL-05; whichever 
occurs latest.
    (10) For AWL 47-AWL-06, ``NGS--NEA Distribution Ducting 
Integrity'': Within 10,682 flight hours after the date of issuance 
of the original airworthiness certificate or the date of issuance of 
the original export certificate of airworthiness; or within 10,682 
flight hours after accomplishment of the actions specified in Boeing 
Service Bulletin 777-47-0002; or within 10,682 flight hours after 
the most recent inspection was performed as specified in 47-AWL-06; 
whichever occurs latest.

(h) Additional Acceptable Wire Types and Sleeving

    As an option, when accomplishing the actions required by 
paragraph (g) of this AD, the changes specified in paragraphs (h)(1) 
and (2) of this AD are acceptable.
    (1) Where AWL No. 28-AWL-11 identifies wire types BMS 13-48, BMS 
13-58, and BMS 13-60, the following wire types are acceptable: MIL-
W-22759/16, SAE AS22759/16 (M22759/16), MIL-W-22759/32, SAE AS22759/
32 (M22759/32), MIL-W-22759/34, SAE AS22759/34 (M22759/34), MIL-W-
22759/41, SAE AS22759/41 (M22759/41), MIL-W-22759/86, SAE AS22759/86 
(M22759/86), MIL-W-22759/87, SAE AS22759/87 (M22759/87), MIL-W-
22759/92, and SAE AS22759/92 (M22759/92); and MIL-C-27500 and NEMA 
WC 27500 cables constructed from these military or SAE specification 
wire types, as applicable.
    (2) Where AWL No. 28-AWL-11 identifies TFE-2X Standard wall 
(manufactured as specified in MIL-I-23053) for wire sleeving, the 
following sleeving materials are acceptable: Roundit 2000NX and 
Varglas Type HO, HP, or HM.

(i) No Alternative Actions, Intervals, or Critical Design Configuration 
Control Limitations (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

[[Page 16137]]

actions, intervals, and CDCCLs are approved as an alternative method 
of compliance (AMOC) in accordance with the procedures specified in 
paragraph (k) of this AD.

(j) Terminating Actions

    Accomplishment of the revision required by paragraph (g) of this 
AD terminates the requirements specified in paragraphs (j)(1) and 
(2) of this AD for that airplane.
    (1) All requirements of AD 2008-11-13 for Model 777-200, -200LR, 
-300, and -300ER series airplanes only.
    (2) All requirements of AD 2014-09-09.

(k) 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 paragraph (l)(1) of this AD. Information may be 
emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (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.

(l) Related Information

    (1) For more information about this AD, contact Kevin Nguyen, 
Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 
2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-
3555; email: kevin.nguyen@faa.gov.
    (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 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 March 2, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-06022 Filed 3-25-21; 8:45 am]
BILLING CODE 4910-13-P


