Federal Register / Vol. 86, No. 133 / Thursday, July 15, 2021 / Rules and Regulations 37219 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2020–1030; Project 

Identifier AD–2020–01079–T; Amendment 

39–21607; AD 2021–13–02] 

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 certain 

The Boeing Company Model 777–300ER 

series airplanes. This AD was prompted 

by a report that a production design 

change to certain insulation blankets 

inadvertently opened up leakage paths 

for halon and smoke to escape from the 

aft cargo compartment in the event of a 

fire. This AD requires installation of an 

insulation blanket assembly on top of 

existing insulation blankets in certain 

areas of the forward endwall in the aft 

cargo compartment. The FAA is issuing 

this AD to address the unsafe condition 

on these products. 

DATES: This AD is effective August 19, 

2021. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of August 19, 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– 

1030. 

Examining the AD Docket 

You may examine the AD docket at 

https://www.regulations.gov by 

searching for and locating Docket No. 

FAA–2020–1030; 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: 

Courtney Kronenberger, Aerospace 

Engineer, Cabin Safety and 

Environmental Systems Section, FAA, 

Seattle ACO Branch, 2200 South 216th 

St., Des Moines, WA 98198; phone and 

fax: 206–231–3986; email: 

courtney.a.kronenberger@faa.gov. 

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 certain The Boeing Company 

Model 777–300ER series airplanes. The 

NPRM published in the Federal 

Register on December 29, 2020 (85 FR 

85557). The NPRM was prompted by 

report indicating that a production 

design change to certain insulation 

blankets inadvertently opened up 

leakage paths for halon and smoke to 

escape from the aft cargo compartment 

in the event of a fire. In the NPRM, the 

FAA proposed to require installation of 

an insulation blanket assembly on top of 

existing insulation blankets in certain 

areas of the forward endwall in the aft 

cargo compartment. The FAA is issuing 

this AD to address increased leakage 

paths, which, in the event of a fire, 

could result in loss of fire suppressant 

in the cargo compartment, and could 

lead to an uncontained fire and 

subsequent loss of the airplane. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received comments from 

one commenter, Boeing, who supported 

the NPRM without change. 

The FAA received additional 

comments from one commenter, United 

Airlines. The following presents the 

comments received on the NPRM and 

the FAA’s response to each comment. 

Request for Update to Illustrated Parts 

Catalog (IPC) 

United Airlines stated that it agrees 

with the intent of the proposed AD. 

United Airlines also recommended that 

Boeing update the applicable IPC to 

show configuration control of the new 

part numbers that are installed during 

the accomplishment of the actions 

specified in the referenced service 

information. United Airlines noted that 

the update would provide proper 

configuration control and 

documentation support to maintain the 

new insulation blanket installation 

changes made prior to the release of the 

AD. United Airlines also asserted that 

the change could mitigate incorrect 

blanket installation. 

The FAA acknowledges the 

commenter’s recommendation and 

reasoning. However, the FAA does not 

control or require changes to the IPC. 

The FAA has not changed this AD in 

this regard. 

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 Special 

Attention Requirements Bulletin 777– 

25–0753 RB, dated July 31, 2020. This 

service information specifies procedures 

for installing an insulation blanket 

assembly on top of existing insulation 

blankets on the left and right side corner 

of the forward endwall in the aft cargo 

compartment. 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 22 airplanes of U.S. registry. The 

FAA estimates the following costs to 

comply with this AD: 

ESTIMATED COSTS FOR REQUIRED ACTIONS

Action Labor cost Parts cost Cost per 

product 

Cost on U.S. 

operators 

Insulation blanket installation .......................... 1 work-hour × $85 per hour = $85 ................. $240 $325 $7,150 


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37220 Federal Register / Vol. 86, No. 133 / Thursday, July 15, 2021 / Rules and Regulations 

According to the manufacturer, some 

or all of the costs of this AD may be 

covered under warranty, thereby 

reducing the cost impact on affected 

operators. The FAA does not control 

warranty coverage for affected operators. 

As a result, the FAA has included all 

known costs in the cost estimate. 

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 PROJECT NO. 15021–000 

■ 1. The authority citation for part 39 

continues to read as follows: 

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

§ 39.13 [Amended] Project No. 15021–000 

■ 2. The FAA amends § 39.13 by adding 

the following new airworthiness 

directive: 

2021–13–02 The Boeing Company: 

Amendment 39–21607; Docket No. 

FAA–2020–1030; Project Identifier AD– 

2020–01079–T. 

(a) Effective Date 

This airworthiness directive (AD) is 

effective August 19, 2021. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to The Boeing Company 

Model 777–300ER series airplanes, 

certificated in any category, as identified in 

Boeing Special Attention Requirements 

Bulletin 777–25–0753 RB, dated July 31, 

2020. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 25, Equipment/Furnishings. 

(e) Unsafe Condition 

This AD was prompted by a report that a 

production design change to certain 

insulation blankets inadvertently opened up 

leakage paths for halon and smoke to escape 

from the aft cargo compartment in the event 

of a fire. The FAA is issuing this AD to 

address increased leakage paths, which, in 

the event of a fire, could result in loss of fire 

suppressant in the cargo compartment, and 

could lead to an uncontained fire and 

subsequent loss 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 Special 

Attention Requirements Bulletin 777–25– 

0753 RB, dated July 31, 2020, do all 

applicable actions identified in, and in 

accordance with, the Accomplishment 

Instructions of Boeing Special Attention 

Requirements Bulletin 777–25–0753 RB, 

dated July 31, 2020. 

Note 1 to paragraph (g): Guidance for 

accomplishing the actions required by this 

AD can be found in Boeing Special Attention 

Service Bulletin 777–25–0753, dated July 31, 

2020, which is referred to in Boeing Special 

Attention Requirements Bulletin 777–25– 

0753 RB, dated July 31, 2020. 

(h) Exceptions to Service Information 

Specifications 

Where Boeing Special Attention 

Requirements Bulletin 777–25–0753 RB, 

dated July 31, 2020, uses the phrase ‘‘the 

original issue date of the Requirements 

Bulletin 777–25–0753 RB,’’ this AD requires 

using ‘‘the effective date of this AD.’’ 

(i) 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 (j)(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. 

(j) Related Information 

(1) For more information about this AD, 

contact Courtney Kronenberger, Aerospace 

Engineer, Cabin Safety and Environmental 

Systems Section, FAA, Seattle ACO Branch, 

2200 South 216th St., Des Moines, WA 

98198; phone and fax: 206–231–3986; email: 

courtney.a.kronenberger@faa.gov. 

(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 Special Attention Requirements 

Bulletin 777–25–0753 RB, dated July 31, 

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 

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 


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Federal Register / Vol. 86, No. 133 / Thursday, July 15, 2021 / Rules and Regulations 37221 

National Archives and Records 

Administration (NARA). For information on 

the availability of this material at NARA, 

email fedreg.legal@nara.gov, or go to: https:// 

www.archives.gov/federal-register/cfr/ibrlocations.html. 

Issued on June 9, 2021. 

Lance T. Gant, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2021–15028 Filed 7–14–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2020–0981; Project 

Identifier AD–2020–00919–T; Amendment 

39–21615; AD 2021–13–10] 

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 certain 

The Boeing Company Model 777 

airplanes. This AD was prompted by 

reports indicating that during 

investigation of a fuel leak, fatigue 

cracking was found on the forward 

inboard side of the fuel tank access door 

cutouts on the left and right lower wing 

skin. The cause of the cracking is 

attributed to corrosion damage. This AD 

requires repetitive inspections for any 

existing repair of the wing lower skin 

fuel tank and dry bay access door 

cutouts on the left and right lower wing 

skin, and applicable on-condition 

actions. The FAA is issuing this AD to 

address the unsafe condition on these 

products. 

DATES: This AD is effective August 19, 

2021. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of August 19, 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– 

0981. 

Examining the AD Docket 

You may examine the AD docket at 

https://www.regulations.gov by 

searching for and locating Docket No. 

FAA–2020–0981; 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: Luis 

A. Cortez-Muniz, Aerospace Engineer, 

Airframe Section, FAA, Seattle ACO 

Branch, 2200 South 216th St., Des 

Moines, WA 98198; phone and fax: 206– 

231–3958; email: luis.a.cortez-muniz@

faa.gov. 

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 certain The Boeing Company 

Model 777 airplanes. The NPRM 

published in the Federal Register on 

November 18, 2020 (85 FR 73430). The 

NPRM was prompted by reports 

indicating that during investigation of a 

fuel leak, fatigue cracking was found on 

the forward inboard side of the fuel tank 

access door cutouts on the left and right 

lower wing skin. The cause of the 

cracking is attributed to corrosion 

damage. In the NPRM, the FAA 

proposed to require repetitive 

inspections for any existing repair of the 

wing lower skin fuel tank and dry bay 

access door cutouts on the left and right 

lower wing skin, and applicable oncondition actions. The FAA is issuing 

this AD to address fatigue cracking, 

which could result in the inability of a 

principal structural element to sustain 

limit load, and consequent reduced 

structural integrity of the airplane. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received comments from 

Boeing and United Airlines. Those 

commenters supported the NPRM 

without change. 

The FAA received additional 

comments from six commenters, 

including AeroLogic, Air France, 

American Airlines, Emirates, FedEx 

Express (FedEx), and one individual. 

The following presents the comments 

received on the NPRM and the FAA’s 

response to each comment. 

Request To Revise Compliance Time 

AeroLogic, Air France, American 

Airlines, and Emirates asked that the 

FAA re-evaluate and extend the initial 

and repetitive calendar-based 

compliance times in the proposed AD to 

match heavy maintenance intervals. The 

commenters stated that the 1,125-day 

compliance time does not align with 

existing MPD intervals of 3,000 days 

and 4,500 days or the existing heavy 

maintenance intervals. One commenter 

stated that, as a long-range freight 

specialist it has an average flight hour/ 

flight cycle ratio of 6.0 to 6.3, thus 

reaching the flight hour LOV of the 

Model 777F before reaching the flight 

cycle utilization that the aircraft with 

crack findings had at the time of crack 

detection. The commenters also stated 

that more frequent opening and closing 

of the access doors could increase the 

chance of corrosion. although the 

airplane with the initial crack finding 

was 19 years old at the time cracking 

was found, and Boeing reported that 

only minimal corrosion was found 

during lab testing of the cracking. 

The FAA does not agree with the 

requests to extend the compliance time. 

The compliance times were coordinated 

with the design approval holder based 

on its analysis and fleet findings. 

Additionally, the commenters did not 

provide substantiation data that shows 

that the proposed extended inspection 

intervals provide adequate crack 

detection. However, under the 

provisions of paragraph (i) of this AD, 

the FAA will consider requests for 

approval of an extension of the 

compliance time if sufficient data are 

submitted to substantiate that the 

extension would provide an acceptable 

level of safety. This AD has not been 

changed in this regard. 

Request To Change Exception 

Air France stated that paragraph (h)(1) 

of the proposed AD would require using 

‘‘the effective date of this AD,’’ except 

where Boeing Alert Requirements 

Bulletin 777–57A0118 RB, dated June 

23, 2020, uses the phrase ‘‘the original 

issue date of Requirements Bulletin 

777–57A0118 RB’’ in a note or flag note. 

Air France noted that making the 

exception depend on a note or flag note 

is confusing. Air France asked that the 

FAA change the exception to apply 

throughout the proposed AD 

requirements instead of depending on 


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