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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37222 Federal Register / Vol. 86, No. 133 / Thursday, July 15, 2021 / Rules and Regulations 

where the phrase ‘‘the original issue 

date of Requirements Bulletin 777– 

57A0118 RB’’ is used. 

The FAA agrees to change the 

exception in paragraph (h)(1) of this AD. 

The exception specified in paragraph 

(h)(1) of the proposed AD was intended 

to apply only to certain dates referenced 

in Boeing Alert Requirements Bulletin 

777–57A0118 RB, dated June 23, 2020. 

The exception applies to the associated 

date in the Effectivity paragraph and the 

Condition and Compliance columns of 

tables 1 through 10 of paragraph 1.E., 

‘‘Compliance,’’ and not to flag note (c) 

in the tables. Repairs accomplished 

relative to the original issue date of 

Requirements Bulletin 777–57A0118 

RB, as specified in flag note (c) in those 

tables, do not need an exception for 

compliance with this AD. The FAA has 

changed paragraph (h)(1) of this AD 

accordingly. 

Request To Change Estimated Work 

Hours for Inspection 

FedEx stated that the hours estimated 

for ‘‘the inspection’’ in the Costs of 

Compliance section of the NPRM is 

lower than its forecast of 80 work-hours 

and 60 elapsed hours. FedEx noted that 

the NPRM specified only 34 workhours. 

The FAA infers that the commenter is 

asking to increase the work hours for the 

general visual inspections specified in 

the Costs of Compliance section of this 

AD to 80 work-hours. We do not agree. 

The estimate of 34 work-hours includes 

access and close for accomplishing the 

general visual inspections. The FAA 

recognizes that additional on-condition 

inspections could be required, 

depending on the results of the general 

visual inspection. However, since the 

FAA has no way of determining the 

number of aircraft that might need these 

on-condition inspections, the hours and 

cost estimates for the additional 

inspections are provided in the oncondition actions table on a per-airplane 

basis. This AD has not been changed in 

this regard. 

Request To Allow Detailed Inspections 

for Certain Airplanes 

One individual asked that the FAA 

allow detailed and high frequency eddy 

current (HFEC) inspections for airplanes 

in Group 3, Condition 17 (for the right 

wing), similar to the detailed and HFEC 

inspections allowed for airplanes in 

Group 3, Condition 14 (for the left 

wing). The commenter observed that 

Condition 14 specifies detailed and 

HFEC inspections, whereas Condition 

17 specifies contacting Boeing. The 

commenter stated that these conditions 

are the same and symmetrical for the 

left- and right-hand wings. 

The FAA does not agree with the 

commenter’s request. Configurations on 

Group 3 airplanes may be different on 

the left and right sides due to previously 

approved repairs or production changes. 

The inspection procedures were 

coordinated with the design approval 

holder regarding the airplane 

configurations. Therefore, this AD has 

not been changed in this regard. 

Request To Clarify Cost Estimate 

AeroLogic stated that the proposed 

compliance time would result in an 

economic impact that was not 

considered in the operator burden 

provided in the cost estimate. 

The FAA provides the following 

clarification: The cost information 

describes only the direct costs of the 

specific actions required by this AD. 

Based on the best data available, the 

manufacturer provided the number of 

work hours necessary to do the required 

actions. This number represents the 

time necessary to perform only the 

actions actually required by this AD. We 

recognize that, in doing the actions 

required by an AD, operators might 

incur incidental costs in addition to the 

direct costs. The cost analysis in AD 

rulemaking actions, however, typically 

does not include incidental costs such 

as the time necessary for planning or 

time necessitated by other 

administrative actions. Those incidental 

costs, which might vary significantly 

among operators, are almost impossible 

to calculate. 

Aerologic also stated that the aircraft 

maintenance manual (AMM) 

recommends using new gaskets to 

prevent fuel leaks after each tank access. 

Therefore, the parts cost should be 

estimated with up to 240 USD per 

gasket. At 18 Access Doors opened for 

every repeat inspection, this sums up to 

4,320 USD per aircraft for each 

inspection cycle. 

The FAA does not agree to change the 

estimated parts costs, as the actions in 

the AMM are not required by this AD. 

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 777–57A0118 

RB, dated June 23, 2020. The service 

information describes procedures for 

repetitive general visual inspections for 

any existing repair of the fuel tank 

access door cutouts on the left and right 

lower wing skin, and applicable oncondition actions. On-condition actions 

include detailed and HFEC inspections 

for any corrosion, fretting, and cracking; 

a blend out of corrosion or fretting that 

meets certain criteria; and repair. 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 221 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 

General visual inspection ....... Up to 34 work-hours × $85 

per hour = Up to $2,890 

per inspection cycle.

$0 Up to $2,890 per inspection 

cycle.

Up to $638,690 per inspection 

cycle. 

The FAA estimates the following 

costs to do any necessary on-condition 

actions that would be required. The 

FAA has no way of determining the 

number of aircraft that might need these 

on-condition actions: 


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Federal Register / Vol. 86, No. 133 / Thursday, July 15, 2021 / Rules and Regulations 37223 

ESTIMATED COSTS OF ON-CONDITION ACTIONS * 

Action Labor cost Parts cost Cost per product Cost on U.S. operators 

Blend out of corrosion or fretting.2 work-hours × $85 per hour 

= $170 per blend out.

$0 $170 per blend out ................ $170 per blend out. 

Repair of crack 0.2 inch or 

less with no blend repair or 

keyway trim modification.

2 work-hours × $85 per hour 

= $170 per crack.

0 $170 per crack ....................... $170 per crack. 

Detailed and HFEC inspections.2 work-hours × $85 per hour 

= $170 per access door 

cutout.

0 $170 per access door cutout $170 per access door cutout. 

* The FAA has received no definitive data on which to base the cost estimates for the on-condition repairs specified in this AD that require obtaining an alternative method of compliance (AMOC). 

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 

■ 1. The authority citation for part 39 

continues to read as follows: 

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

§ 39.13 [Amended] 

■ 2. The FAA amends § 39.13 by adding 

the following new airworthiness 

directive: 

2021–13–10 The Boeing Company: 

Amendment 39–21615; Docket No. 

FAA–2020–0981; Project Identifier AD– 

2020–00919–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 777–200, –200LR, –300, –300ER, and 

777F series airplanes, certificated in any 

category, as identified in Boeing Alert 

Requirements Bulletin 777–57A0118 RB, 

dated June 23, 2020. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 57, Wings. 

(e) Unsafe Condition 

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. The FAA is issuing this 

AD to address such cracking, which could 

result in the inability of a principal structural 

element to sustain limit load, and consequent 

reduced 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 777–57A0118 RB, 

dated June 23, 2020, do all applicable actions 

identified in, and in accordance with, the 

Accomplishment Instructions of Boeing Alert 

Requirements Bulletin 777–57A0118 RB, 

dated June 23, 2020. 

Note 1 to paragraph (g): Guidance for 

accomplishing the actions required by this 

AD can be found in Boeing Alert Service 

Bulletin 777–57A0118, dated June 23, 2020, 

which is referred to in Boeing Alert 

Requirements Bulletin 777–57A0118 RB, 

dated June 23, 2020. 

(h) Exceptions to Service Information 

Specifications 

(1) Where the ‘‘Effectivity’’ paragraph, and 

the Condition and Compliance Time columns 

of the tables in the ‘‘Compliance’’ paragraph, 

of Boeing Alert Requirements Bulletin 777– 

57A0118 RB, dated June 23, 2020, use the 

phrase ‘‘the original issue date of 

Requirements Bulletin 777–57A0118 RB,’’ 

this AD requires using ‘‘the effective date of 

this AD.’’ 

(2) Where Boeing Alert Requirements 

Bulletin 777–57A0118 RB, dated June 23, 

2020, specifies contacting Boeing for repair 

instructions or for alternative inspections: 

This AD requires doing the repair, or doing 

the alternative inspections and applicable oncondition actions 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, 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, 


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37224 Federal Register / Vol. 86, No. 133 / Thursday, July 15, 2021 / Rules and Regulations 

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 

For more information about this AD, 

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. 

(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 

777–57A0118 RB, dated June 23, 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 

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 10, 2021. 

Ross Landes, 

Deputy Director for Regulatory Operations, 

Compliance & Airworthiness Division, 

Aircraft Certification Service. 

[FR Doc. 2021–15029 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–2021–0258; Project 

Identifier AD–2020–01565–T; Amendment 

39–21637; AD 2021–14–10] 

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 747–400, 

747–400D, and 747–400F series 

airplanes. This AD was prompted by 

reports of burned Boeing Material 

Specification (BMS) 8–39 urethane foam 

found in certain locations on the 

airplane; investigation revealed that the 

fire-retardant properties degrade with 

age. This AD requires inspecting the 

insulation blankets in certain areas of 

the forward cargo compartment for 

exposed BMS 8–39 urethane foam, not 

encapsulated by a protective fire 

resistant barrier, and for seal integrity, 

and replacing the BMS 8–39 urethane 

foam and seal if necessary. 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–2021– 

0258. 

Examining the AD Docket 

You may examine the AD docket at 

https://www.regulations.gov by 

searching for and locating Docket No. 

FAA–2021–0258; 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: Julie 

Linn, Aerospace Engineer, Cabin Safety 

and Environmental Systems Section, 

FAA, Seattle ACO Branch, 2200 South 

216th St., Des Moines, WA 98198; 

phone and fax: 206–231–3584; email: 

Julie.Linn@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 747–400, 747–400D, and 747– 

400F series airplanes. The NPRM 

published in the Federal Register on 

April 13, 2021 (86 FR 19160). The 

NPRM was prompted by reports of 

burned BMS 8–39 urethane foam found 

in certain locations on the airplane; 

investigation revealed that the fireretardant properties degrade with age. In 

the NPRM, the FAA proposed to require 

inspecting the insulation blankets in 

certain areas of the forward cargo 

compartment for exposed BMS 8–39 

urethane foam, not encapsulated by a 

protective fire resistant barrier, and for 

seal integrity, and replacing the BMS 8– 

39 urethane foam and seal if necessary. 

The FAA is issuing this AD to address 

degraded BMS 8–39 urethane foam used 

in seals, which may fail to maintain 

sufficient halon concentrations in the 

cargo compartments to extinguish or 

contain fire or smoke, and may fail to 

prevent penetration of fire or smoke in 

areas of the airplane that are difficult to 

access for fire and smoke detection or 

suppression, which could result in loss 

of control of the airplane. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received comments from Air 

Line Pilots Association, International 

(ALPA), who supported the NPRM 

without change. 

Conclusion 

The FAA reviewed the relevant data, 

considered the comment 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. 


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