Federal Register / Vol. 85, No. 247 / Wednesday, December 23, 2020 / Rules and Regulations 83755 

accordance with the procedures specified in 

paragraph (j) of this AD. 

(j) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, Los Angeles ACO Branch, 

FAA, has the authority to approve AMOCs 

for this AD, if requested using the procedures 

found in 14 CFR 39.19. In accordance with 

14 CFR 39.19, send your request to your 

principal inspector or local Flight Standards 

District 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 (k)(1) of 

this AD. Information may be emailed to: 9- 

ANM-LAACO-AMOC-Requests@faa.gov. 

(2) Before using any approved AMOC, 

notify your appropriate principal inspector, 

or lacking a principal inspector, the manager 

of the local flight standards district office/ 

certificate holding district office. 

(3) An AMOC that provides an acceptable 

level of safety may be used for any repair, 

modification, or alteration required by this 

AD if it is approved by The Boeing Company 

Organization Designation Authorization 

(ODA) that has been authorized by the 

Manager, Los Angeles ACO Branch, FAA, to 

make those findings. To be approved, the 

repair method, modification deviation, or 

alteration deviation must meet the 

certification basis of the airplane, and the 

approval must specifically refer to this AD. 

(k) Related Information 

(1) For more information about this AD, 

contact Wayne Ha, Aerospace Engineer, 

Airframe Section, FAA, Los Angeles ACO 

Branch, 3960 Paramount Boulevard, 

Lakewood, CA 90712–4137; phone: 562–627– 

5238; email: Wayne.Ha@faa.gov. 

(2) Service information identified in this 

AD that is not incorporated by reference is 

available at the addresses specified in 

paragraphs (l)(3) and (4) of this AD. 

(l) 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 

737–57A1348 RB, dated June 1, 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 December 9, 2020. 

Lance T. Gant, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2020–28270 Filed 12–22–20; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2020–0465; Product 

Identifier 2020–NM–074–AD; Amendment 

39–21363; AD 2020–26–08] 

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 The 

Boeing Company Model 787–8, 787–9, 

and 787–10 airplanes powered by Rolls 

Royce Trent 1000 engines. This AD was 

prompted by reports of damage to the 

inner fixed structure (IFS) forward 

upper fire seal and damage to thermal 

insulation blankets in the forward upper 

area of the thrust reverser (TR). This AD 

requires repetitive inspections of the IFS 

forward upper fire seal and thermal 

insulation blankets in the forward upper 

area of the TR for damage and 

applicable on-condition actions. The 

FAA is issuing this AD to address the 

unsafe condition on these products. 

DATES: This AD is effective January 27, 

2021. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of January 27, 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 on the internet at 

https://www.regulations.gov by 

searching for and locating Docket No. 

FAA–2020–0465. 

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–2020– 

0465; 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: Tak 

Kobayashi, Aerospace Engineer, 

Propulsion Section, FAA, Seattle ACO 

Branch, 2200 South 216th St., Des 

Moines, WA; phone: 206–231–3553; 

email: Takahisa.Kobayashi@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Discussion 

The FAA issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 by adding an AD that would 

apply to The Boeing Company Model 

787–8, 787–9, and 787–10 airplanes 

powered by Rolls Royce Trent 1000 

engines. The NPRM published in the 

Federal Register on June 16, 2020 (85 

FR 36352). The NPRM was prompted by 

reports of damage to the IFS forward 

upper fire seal and damage to thermal 

insulation blankets in the forward upper 

area of the TR. The NPRM proposed to 

require repetitive inspections of the IFS 

forward upper fire seal and thermal 

insulation blankets in the forward upper 

area of the TR for damage and 

applicable on-condition actions. 

The FAA is issuing this AD to address 

damage to the IFS forward upper fire 

seal and the thermal insulation blankets 

of the TR due to airflow through 

structural gapping that could occur at 

the interface between the leading edge 

of the IFS and the engine splitter 

structure during flight. Failure of the 

IFS forward upper fire seal could cause 

the loss of seal pressurization and 

degrade the ability to detect and 

extinguish an engine fire, resulting in an 

uncontrolled fire. Damage to the TR 

insulation blanket could result in 

thermal damage to the TR inner wall, 

the subsequent release of engine exhaust 

components, and consequent damage to 

critical areas of the airplane. 

Furthermore, damage to the TR inner 

wall and IFS forward upper fire seal 

could compromise the integrity of the 

firewall and its ability to contain an 

engine fire, resulting in an uncontrolled 

fire. 


jbell on DSKJLSW7X2PROD with RULES
83756 Federal Register / Vol. 85, No. 247 / Wednesday, December 23, 2020 / Rules and Regulations 

Comments 

The FAA gave the public the 

opportunity to participate in developing 

this final rule. The following presents 

the comments received on the NPRM 

and the FAA’s response to each 

comment. 

Request for Clarification on Whether 

the Unsafe Condition is Likely To Exist 

on Other New Products 

An individual commenter asked how 

likely it is that the same unsafe 

condition addressed in the proposed AD 

is to occur on other new products that 

are currently being evaluated for 

certification by the FAA, including the 

Boeing Model 777X. The commenter 

stated that the use of an electric thruster 

instead of a hydraulically-driven thrust 

reverser actuator would reduce the 

maintenance of a hydraulic system, and 

eliminate potential corrosion and fire 

risk. 

The FAA agrees to clarify. As required 

by 14 CFR 21.21(b)(2), to certify an 

aircraft, the FAA must find that no 

feature or characteristic makes the 

aircraft unsafe. If the unsafe condition 

identified in this AD is determined to 

exist on any product that has not been 

certified by the FAA, the unsafe 

condition must be adequately addressed 

prior to FAA certification of that 

product. No change to this final rule is 

necessary in this regard. 

Request for Explanation Regarding 

Timing of AD Action 

The individual commenter asked why 

there was a 36 month period after 

August 27, 2018 (the effective date of 

AD 2018–15–03 Amendment 39–19335 

(83 FR 34753, July 23, 2018) (AD 2018– 

15–03)), to take action on Boeing Alert 

Service Bulletin B787–81205– 

SB780033–00, Issue 001, dated 

November 1, 2017, which is required by 

AD 2018–15–03. The FAA infers that 

the commenter is referring to the 36- 

month compliance time for 

accomplishing the actions described in 

Boeing Alert Service Bulletin B787– 

81205–SB780033–00, Issue 001, dated 

November 1, 2017. The FAA also infers 

that the commenter is concerned 

regarding the time it took the FAA to 

take AD action to address the unsafe 

condition. 

The FAA agrees to provide 

clarification regarding the timing of the 

publication of AD 2018–15–03 and the 

relationship between AD 2018–15–03 

and this final rule. In the preamble of 

the NPRM preceding this final rule, the 

FAA stated that the proposed AD would 

not supersede or terminate any 

requirement of AD 2018–15–03. AD 

2018–15–03 and this final rule both 

address damage to the IFS forward 

upper fire seal and damage to the thrust 

reverser thermal blanket. However, the 

damage to these areas is the result of 

two different causes. When the FAA 

developed AD 2018–15–03, that AD 

addressed the cause of damage that was 

identified at that time. The FAA 

assessed the level of risk and the 

compliance time, so that mandatory 

actions would be accomplished as soon 

as reasonably practical while 

maintaining an acceptable level of safety 

during the compliance period. The FAA 

determined that a compliance time of 36 

months was adequate to address the 

unsafe condition identified in AD 2018– 

15–03. 

After AD 2018–15–03 was issued, 

Boeing identified an additional cause of 

the unsafe condition that was different 

from the one specified in AD 2018–15– 

03. This newly identified cause could 

similarly result in damage to the IFS 

forward upper fire seal and the thrust 

reverser thermal blanket. This final rule 

addresses the newly identified cause of 

the unsafe condition that was identified 

after AD 2018–15–03 was issued. As 

discussed in the preamble of the NPRM 

and the preamble of this final rule, the 

actions required by this final rule are 

interim action and the FAA may 

consider further rulemaking when a 

final corrective action becomes 

available. 

No change to this final rule is 

necessary in regard to this comment. 

Request for Clarification Regarding 

Inspection Personnel 

The individual commenter also asked 

for clarification regarding what type of 

inspector would perform the 

inspections of the IFS forward upper 

fire seal and thermal blanket specified 

in the proposed AD. The commenter 

asked if the inspections would be 

performed by flight line inspectors or 

FAA inspectors. 

The FAA agrees to provide 

clarification. The inspections required 

by this AD will be performed by 

qualified and certified maintenance 

personnel employed by airlines and 

airplane operators. No change to this 

final rule is necessary in this regard. 

Request To Clarify the Unsafe 

Condition 

Boeing requested that the Discussion 

section and paragraph (e) of the 

proposed AD be revised to clarify the 

unsafe condition. The commenter stated 

that the unsafe condition statement in 

the proposed AD was not accurate. 

However, the commenter did not 

provide an explanation as to why the 

unsafe condition statement was not 

accurate. 

The commenter indicated that in both 

the Discussion section and paragraph (e) 

of the proposed AD the explanation of 

the unsafe condition should be changed 

by removing the phrase ‘‘the loss of seal 

pressurization’’ from ‘‘Failure of the IFS 

forward upper fire seal could cause the 

loss of seal pressurization and degrade 

the ability to detect and extinguish an 

engine fire, resulting in an uncontrolled 

fire,’’ and replace it with the phrase 

‘‘excessive airflow into the core 

compartment firezone.’’ 

The commenter also requested that in 

both the Discussion section and 

paragraph (e) of the proposed AD the 

explanation of the unsafe condition be 

changed by removing the phrase ‘‘the 

subsequent release of engine exhaust 

components, and consequent damage to 

critical areas of the airplane’’ from 

‘‘Damage to the TR insulation blanket 

could result in thermal damage to the 

TR inner wall, the subsequent release of 

engine exhaust components, and 

consequent damage to critical areas of 

the airplane,’’ and replace it with the 

phrase ‘‘compromising the integrity of 

the firewall barrier which would 

increase the risk of an uncontained 

fire.’’ 

The FAA agrees with the commenter’s 

request to clarify that damage to the TR 

inner wall could increase the risk of an 

uncontained fire. The FAA concurs that, 

depending on the level of damage to the 

TR inner wall and IFS forward upper 

fire seal, the capability of the firewall to 

contain an engine fire could be 

compromised, and therefore, it could 

result in an uncontrolled fire. The FAA 

also considers that damage to the IFS 

forward upper fire seal has the same 

effect. Although the FAA has already 

identified the potential for an 

uncontrolled fire as part of the unsafe 

condition addressed by this AD, the 

FAA has revised the Discussion section 

and paragraph (e) of this AD to provide 

additional clarification on this point. 

The FAA disagrees with the 

commenter’s request to remove the 

reference to ‘‘loss of seal pressurization 

and’’ from the description of the unsafe 

condition. This final rule addresses 

structural gapping that could occur 

between the leading edge of the IFS and 

the engine splitter structure during 

flight. Airflow through this structural 

gapping could damage the IFS forward 

upper fire seal and the thrust reverser 

thermal blanket. When the IFS forward 

fire seal is damaged, airflow can pass 

through the damaged areas of the IFS 

forward fire seal in addition to airflow 

through structural gapping, and this 

condition could further degrade the 


jbell on DSKJLSW7X2PROD with RULES
Federal Register / Vol. 85, No. 247 / Wednesday, December 23, 2020 / Rules and Regulations 83757 

ability to detect and extinguish an 

engine fire, and also damage the TR 

thermal blanket. The FAA’s intent was 

to explain the effect of airflow through 

the damaged IFS forward fire seal due 

to loss of seal pressurization caused by 

the failure of the IFS forward upper fire 

seal. The FAA has not revised this AD 

in this regard. 

The FAA also disagrees with the 

commenter’s request to remove ‘‘the 

subsequent release of engine exhaust 

components, and consequent damage to 

critical areas of the airplane’’ from the 

description of the unsafe condition. The 

FAA has identified the potential of 

engine components departing the 

airplane due to damage to the TR inner 

wall as part of the unsafe condition 

addressed in this AD. This failure effect 

has been similarly discussed and 

addressed in a number of previously 

issued ADs including AD 2018–15–03, 

which is related to this AD. This AD has 

not been revised in this regard. 

Request To Revise the Proposed Cost 

Estimates 

Boeing requested that the cost 

estimate in the NPRM be revised. 

Boeing stated that it initially 

communicated to the FAA that the 

manpower estimate of 0.5 man-hour for 

fire seal inspection and 0.5 man-hour 

for thermal blanket inspection was 

meant to be per engine, instead of per 

thrust reverser half as the FAA 

considered under the estimated cost 

provided in the NPRM. Boeing 

explained that the corrected manpower 

estimate for the fire seal inspection 

should be 0.25 man-hour per thrust 

reverser half, and the corrected 

manpower estimate for the thermal 

blanket inspection should be 0.25 manhour per thrust reverser half. Boeing 

recommended that instead of 4 workhours × $85 per hour = $340 per 

inspection cycle, the FAA update the 

labor cost for the inspection to 2 workhours for a cost of $170 per inspection 

cycle. Boeing asserted that this would 

change the cost on U.S. operators to 

$2,380 per inspection cycle, based on 14 

U.S. airplanes. 

The FAA agrees with Boeing’s 

observation that the cost estimate in the 

NPRM was incorrect based upon 

information that was incorrectly 

communicated from Boeing to the FAA. 

The FAA has revised the Costs of 

Compliance in this final rule. 

Conclusion 

The FAA reviewed the relevant data, 

considered the comments received, and 

determined that air safety and the 

public interest require adopting this 

final rule with the changes described 

previously and minor editorial changes. 

The FAA has determined that these 

minor changes: 

• Are consistent with the intent that 

was proposed in the NPRM for 

addressing the unsafe condition; and 

• Do not add any additional burden 

upon the public than was already 

proposed in the NPRM. 

The FAA also determined that these 

changes will not increase the economic 

burden on any operator or increase the 

scope of this final rule. 

Related Service Information Under 1 

CFR Part 51 

The FAA reviewed Boeing Alert 

Requirements Bulletin B787–81205– 

SB780041–00 RB, Issue 001, dated 

March 31, 2020. The service information 

describes procedures for repetitive 

inspections of the IFS forward upper 

fire seal and thermal insulation blankets 

of the TR for damage and applicable oncondition actions. Damage to a forward 

upper fire seal includes cuts, splits, 

nicks, punctures, and missing sections. 

Damage to an upper thermal blanket 

includes tears, cuts, missing metal skin, 

missing insulation, and overtemperature conditions shown by 

discoloration or scorching. The oncondition actions include replacing any 

damaged forward upper fire seal with a 

new fire seal having an appropriate part 

number, and replacing any damaged 

forward upper thermal blanket with a 

new thermal blanket. 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. 

Interim Action 

The FAA considers this AD interim 

action. If final action is later identified, 

the FAA might consider further 

rulemaking then. 

Costs of Compliance 

The FAA estimates that this AD 

affects 14 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 

Inspection .... 2 work-hours × $85 per hour = $170 per inspection 

cycle.

$0 $170 per inspection cycle $2,380 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: 

ESTIMATED COSTS OF ON-CONDITION ACTIONS

Action Labor cost Parts cost Cost per product 

Fire seal replacement .. 2 work-hours × $85 per hour = $170 per TR 

half.

$1,365 per TR half ..... $1,535 per TR half (4 TR halves per airplane). 

Thermal blanket replacement.1 work-hour × $85 per hour = $85 per TR 

half.

$17,855 per TR half ... $17,940 per TR half (4 TR halves per airplane). 

According to the manufacturer, some 

or all of the costs of this AD may be 

covered under warranty by Goodrich, 

thereby reducing the cost impact on 

affected individuals. The FAA does not 

control warranty coverage for affected 

individuals. 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 


jbell on DSKJLSW7X2PROD with RULES
83758 Federal Register / Vol. 85, No. 247 / Wednesday, December 23, 2020 / Rules and Regulations 

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. 

Adoption of 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 (AD): 

2020–26–08 The Boeing Company: 

Amendment 39–21363; Docket No. 

FAA–2020–0465; Product Identifier 

2020–NM–074–AD. 

(a) Effective Date 

This AD is effective January 27, 2021. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to The Boeing Company 

Model 787–8, 787–9, and 787–10 airplanes, 

certificated in any category, powered by Rolls 

Royce Trent 1000 engines. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 78, Engine Exhaust. 

(e) Unsafe Condition 

This AD was prompted by reports of 

damage to the inner fixed structure (IFS) 

forward upper fire seal and damage to 

thermal insulation blankets in the forward 

upper area of the thrust reverser (TR). The 

FAA is issuing this AD to address the damage 

to the IFS forward upper fire seal and the 

thermal insulation blankets of the TR due to 

airflow through structural gapping that could 

occur at the interface between the leading 

edge of the IFS and the engine splitter 

structure during flight. Failure of the IFS 

forward upper fire seal could cause the loss 

of seal pressurization and degrade the ability 

to detect and extinguish an engine fire, 

resulting in an uncontrolled fire. Damage to 

the TR insulation blanket could result in 

thermal damage to the TR inner wall, the 

subsequent release of engine exhaust 

components, and consequent damage to 

critical areas of the airplane. Furthermore, 

damage to the TR inner wall and IFS forward 

upper fire seal could compromise the 

integrity of the firewall and its ability to 

contain an engine fire, resulting in an 

uncontrolled fire. 

(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 B787–81205– 

SB780041–00 RB, Issue 001, dated March 31, 

2020, do all applicable actions identified in, 

and in accordance with, the Accomplishment 

Instructions of Boeing Alert Requirements 

Bulletin B787–81205–SB780041–00 RB, Issue 

001, dated March 31, 2020. 

Note 1 to paragraph (g): Guidance for 

accomplishing the actions required by this 

AD can be found in Boeing Alert Service 

Bulletin B787–81205–SB780041–00, Issue 

001, dated March 31, 2020, which is referred 

to in Boeing Alert Requirements Bulletin 

B787–81205–SB780041–00 RB, Issue 001, 

dated March 31, 2020. 

(h) Exceptions to Service Information 

Specifications 

Where Boeing Alert Requirements Bulletin 

B787–81205–SB780041–00 RB, Issue 001, 

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

Issue 001 date of Requirements Bulletin 

B787–81205–SB780041–00 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 local Flight Standards 

District 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 local flight standards district office/ 

certificate holding district 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 Tak Kobayashi, Aerospace Engineer, 

Propulsion Section, FAA, Seattle ACO 

Branch, 2200 South 216th St., Des Moines, 

WA; phone: 206–231–3553; email: 

Takahisa.Kobayashi@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 Alert Requirements Bulletin 

B787–81205–SB780041–00 RB, Issue 001, 

dated March 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. 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. 

(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. 


jbell on DSKJLSW7X2PROD with RULES
Federal Register / Vol. 85, No. 247 / Wednesday, December 23, 2020 / Rules and Regulations 83759 

(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 December 9, 2020. 

Lance T. Gant, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2020–28268 Filed 12–22–20; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2020–0458; Product 

Identifier 2020–NM–029–AD; Amendment 

39–21348; AD 2020–25–06] 

RIN 2120–AA64 

Airworthiness Directives; Bombardier, 

Inc., Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Final rule. 

SUMMARY: The FAA is adopting a new 

airworthiness directive (AD) for certain 

Bombardier, Inc., Model BD–100–1A10 

airplanes. This AD was prompted by a 

report that corrosion was found on the 

shock strut cylinders during 

unscheduled maintenance of the nose 

landing gear (NLG). This AD requires a 

modification of the NLG shock strut 

cylinder. The FAA is issuing this AD to 

address the unsafe condition on these 

products. 

DATES: This AD is effective January 27, 

2021. 

The Director of the Federal Register 

approved the incorporation by reference 

of certain publications listed in this AD 

as of January 27, 2021. 

ADDRESSES: For service information 

identified in this final rule, contact 

Bombardier, Inc., 200 Coˆte-Vertu Road 

West, Dorval, Que ́bec H4S 2A3, Canada; 

North America toll-free telephone 1– 

866–538–1247 or direct-dial telephone 

1–514–855–2999; email ac.yul@

aero.bombardier.com; internet http://

www.bombardier.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 on the internet at 

https://www.regulations.gov by 

searching for and locating Docket No. 

FAA–2020–0458. 

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–2020– 

0458; 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: 

Darren Gassetto, Aerospace Engineer, 

Mechanical Systems and Administrative 

Services Section, FAA, New York ACO 

Branch, 1600 Stewart Avenue, Suite 

410, Westbury, NY 11590; telephone 

516–228–7323; fax 516–794–5531; email 

9-avs-nyaco-cos@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Discussion 

Transport Canada Civil Aviation 

(TCCA), which is the aviation authority 

for Canada, has issued Canadian AD 

CF–2019–43, dated November 8, 2019 

(‘‘AD CF–2019–43’’) (also referred to as 

the Mandatory Continuing 

Airworthiness Information, or ‘‘the 

MCAI’’), to correct an unsafe condition 

for certain Bombardier, Inc., Model BD– 

100–1A10 airplanes. You may examine 

the MCAI in the AD docket on the 

internet at https://www.regulations.gov 

by searching for and locating Docket No. 

FAA–2020–0458. 

The FAA issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 by adding an AD that would 

apply to certain Bombardier, Inc., Model 

BD–100–1A10 airplanes. The NPRM 

published in the Federal Register on 

June 3, 2020 (85 FR 34141). The NPRM 

was prompted by a report that corrosion 

was found on the shock strut cylinders 

during unscheduled maintenance of the 

NLG. The NPRM proposed to require a 

modification of the NLG shock strut 

cylinder. The FAA is issuing this AD to 

address corrosion of the NLG, which 

could result in structural failure of the 

NLG. See the MCAI for additional 

background information. 

Comments 

The FAA gave the public the 

opportunity to participate in developing 

this final rule. The following presents 

the comment received on the NPRM and 

the FAA’s response to that comment. 

Request To Revise Certain Compliance 

Language in the Proposed AD 

Flexjet stated that where the 

compliance section of Bombardier 

Service Bulletin 100–32–33, Revision 

02, dated September 30, 2019, and 

Figure 1 to paragraph (g) of the 

proposed AD, specify the compliance 

time for NLG assemblies with more than 

96 months time since new (TSN), the 

compliance time does not take into 

account that the NLG cylinders with 

part number (P/N) 40640–3 and P/N 

40640–5 serialized (next higher 

assembly P/N 40640–105 and 

subcomponents) are life-limited items 

with a 7,500 flight cycle discard 

interval. Flexjet commented that during 

the first 96 month inspection, if the 

operator has high flight cycles, it may 

elect to replace the cylinder at that time. 

Flexjet also commented that the 

compliance section of Bombardier 

Service Bulletin 100–32–33, Revision 

02, dated September 30, 2019, does not 

take into account that a new cylinder 

could be installed at the 96-month 

inspection and it also does not address 

if the cylinder was replaced for another 

reason after the 96-month inspection. 

Flexjet stated that the proposed AD 

needs to be specific on applying to the 

nose gear cylinder and sleeve part 

numbers and not the nose gear or nose 

gear strut assembly part numbers. 

Flexjet also stated that the nose gear 

cylinder and sleeve are the parts with 

corrosion and the primary reason for the 

service information. Flexjet pointed out 

that the sleeve is cut off for inspection 

of the cylinder and the same part 

number sleeve goes back on following 

the inspection. The FAA infers that 

Flexjet was requesting that the language 

in paragraphs (g)(1) and (2) of this AD 

specify that the actions apply to 

airplanes with NLG assemblies having 

NLG cylinder assemblies and sleeves 

with certain part numbers. 

The FAA disagrees with the comment. 

While NLG cylinder assemblies and 

their subcomponents can be replaced 

before or after the 96-month interval 

inspection, paragraphs 2.B. and 2.C. of 

the Accomplishment Instructions of 

Bombardier Service Bulletin 100–32–33, 

Revision 02, dated September 30, 2019, 

ensure the proper corrective actions are 

taken to prevent corrosion with those 

replaced components when reassembled 

on the NLG assembly. This is why the 

identification on the NLG assembly 

modplate is required. In addition, 

paragraph (f) of this AD specifies to, 

‘‘Comply with this AD within the 

compliance times specified, unless 

already done.’’ Therefore, if some of the 

specified corrective actions are already 


jbell on DSKJLSW7X2PROD with RULES