Federal Register / Vol. 86, No. 33 / Monday, February 22, 2021 / Rules and Regulations 10441 

Subpart F—Farm Loan Programs Debt 

Settlement 

■ 2. Amend § 761.403 by revising 

paragraph (c)(3) to read as follows: 

§ 761.403 General. 

* * * * * 

(c) * * * 

(3) The debtor’s account is involved 

in a fiscal irregularity investigation in 

which final action has not been taken or 

the account shows evidence that a 

shortage may exist and an investigation 

will be requested. 

* * * * * 

Steven Peterson, 

Acting Administrator, Farm Service Agency. 

[FR Doc. 2021–03186 Filed 2–19–21; 8:45 am] 

BILLING CODE 3410–05–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2020–0459; Product 

Identifier 2020–NM–049–AD; Amendment 

39–21380; AD 2021–01–04] 

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 all The 

Boeing Company Model 737 series 

airplanes, excluding Model 737–100, 

–200, –200C, –300, –400, and –500 

series airplanes. This AD was prompted 

by reports of cracked or completely 

severed lugs in the upper aft corner stop 

fitting assembly of the forward entry 

door. This AD requires an inspection, a 

measurement, or a records check of that 

assembly to determine the part number, 

and replacement if a certain part is 

found. The FAA is issuing this AD to 

address the unsafe condition on these 

products. 

DATES: This AD is effective March 29, 

2021. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of March 29, 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–2020–0459. 

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– 

0459; 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: 

Michael Bumbaugh, Aerospace 

Engineer, Airframe Section, FAA, 

Seattle ACO Branch, 2200 South 216th 

St., Des Moines, WA 98198; phone and 

fax: 206–231–3522; email: 

michael.bumbaugh@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 all The Boeing Company Model 

737 series airplanes, excluding Model 

737–100, –200, –200C, –300, –400, and 

–500 series airplanes. The NPRM 

published in the Federal Register on 

June 3, 2020 (85 FR 34136). The NPRM 

was prompted by reports of cracked or 

completely severed lugs in the upper aft 

corner stop fitting assembly of the 

forward entry door. Analysis of the 

design of the stop fitting assembly 

revealed that undersized wall thickness 

of the lug made it susceptible to fatigue 

cracking, which may result in the 

forward entry door being unable to 

sustain limit load. In the NPRM, the 

FAA proposed to require an inspection, 

a measurement, or a records check of 

that assembly to determine the part 

number, and replacement if a certain 

part-numbered assembly is installed. 

The FAA is issuing this AD to address 

cracked or completely severed lugs, 

which could result in reduced structural 

integrity of the forward entry door and 

consequent rapid decompression of the 

airplane. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received comments from 

four commenters. The following 

presents the comments received on the 

NPRM and the FAA’s response to each 

comment. 

Effect of Winglets on Accomplishment 

of the Proposed Actions 

Aviation Partners Boeing stated that 

the installation of winglets per 

Supplemental Type Certificate (STC) 

ST00830SE does not affect compliance 

with the proposed actions. 

The FAA agrees that the installation 

of winglets per STC ST00830SE would 

not affect the ability to replace the 

affected stop fitting assembly with a 

newly designed stop fitting assembly as 

required by this AD. Operators of 

airplanes with these winglets do not 

need to request a ‘‘change in product’’ 

alternative method of compliance 

(AMOC) approval as specified in 14 CFR 

39.17. The FAA has redesignated 

paragraph (c) of the proposed AD as 

paragraph (c)(1) of this AD, and added 

paragraph (c)(2) accordingly. 

Request for Compliance Actions at the 

Component Level 

Southwest Airlines (SWA) asked that 

the compliance actions be reported at 

the component level due to the 

interchangeability of the forward entry 

doors between the Model 737 NG and 

737 MAX fleets. 

The FAA infers that the commenter is 

requesting that the AD’s applicability 

point towards the component parts, 

rather than the airplane. The FAA 

acknowledges that the component most 

likely to be rotated is the forward entry 

door because doors are likely removed 

with the stop fittings intact. However, 

the FAA disagrees with changing the 

applicability of this AD because the 

unsafe condition is related to the stop 

fitting assembly and an affected stop 

fitting assembly may be installed on a 

forward entry door of any airplane 

identified in paragraph (c) of this AD. In 

addition, paragraph (i) of this AD, ‘‘Parts 

Installation Prohibition,’’ states that no 

person may install a forward entry door 

that has a stop fitting assembly with part 

number (P/N) 141A6104–3 on any 

airplane. The FAA used this language 

because doors are often rotated among 

aircraft with the stop fitting assembly 

already installed. The FAA has therefore 

determined that an airplane-level 

applicability is appropriate and has not 

changed this AD in this regard. 


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10442 Federal Register / Vol. 86, No. 33 / Monday, February 22, 2021 / Rules and Regulations 

Request for Clarification of Compliance 

Time 

SWA asked for clarification of the 

reference in paragraph (g) of the 

proposed AD to the applicable times 

specified in the ‘‘Compliance’’ 

paragraph of Boeing Alert Requirements 

Bulletin 737–52A1180 RB, dated 

January 24, 2020. SWA asked if once it 

is determined that a P/N 141A6104–3 

fitting is installed on a door through 

records or survey, the fitting must be 

replaced before further flight or whether 

it can be replaced at a later date as long 

as the door is still within its required 

compliance time per the referenced 

service information. 

‘‘Table 1: Forward Entry Door Number 

7 Stop Fitting Assembly Inspection’’ of 

Paragraph 3., ‘‘Compliance’’ of Boeing 

Service Bulletin 737–52A1180, dated 

January 24, 2020, gives the compliance 

time for replacing the P/N 141A6104–3 

fitting if found. The compliance time is 

before 10,000 total flight cycles on the 

forward entry door, or within 5,000 

forward entry door flight cycles after the 

original issue date of Boeing Alert 

Requirements Bulletin 737–52A1180 

RB, dated January 24, 2020, whichever 

occurs later. However, under paragraph 

(h) of this AD, the date for determining 

compliance time is the effective date of 

this AD, and not the issue date of the 

bulletin. Therefore, the FAA clarifies 

that if the compliance time has not yet 

been reached, then the fitting does not 

need to be replaced before further flight. 

The FAA has not changed this AD in 

this regard. 

Request To Change Parts Installation 

Prohibition Paragraph 

SWA asked that the FAA reword 

paragraph (i) of the proposed AD to 

require compliance with the service 

information before installation of the 

fitting instead of prohibiting installation 

of the fitting. 

The intent of paragraph (i) of this AD 

is to prohibit installation of an affected 

part on an airplane with a compliance 

time for this prohibition related to the 

airplane configuration and whether the 

actions specified in Boeing Alert 

Requirements Bulletin 737–52A1180 

RB, dated January 24, 2020, must be 

accomplished on that airplane. The 

FAA has not made the changes 

requested by the commenter. However, 

the FAA has revised paragraph (i) of this 

AD to clarify that, for any airplane 

required to accomplish the actions 

required by paragraph (g) of this AD, the 

parts installation prohibition does not 

take effect until the applicable actions 

required by paragraph (g) of this AD 

have been accomplished on that 

airplane. For airplanes having an 

original airworthiness certificate or 

original export certificate of 

airworthiness dated after the effective 

date of this AD, the parts installation 

prohibition continues to be applicable 

as of the effective date of this AD. 

Request for Correction of Error in 

Service Information 

AIRDO requested the FAA correct an 

error in the service information 

incorporated by reference in paragraph 

(g) of the proposed AD. AIRDO noted 

that page 13 of Boeing Alert 

Requirements Bulletin 737–52A1180 

RB, dated January 24, 2020, refers to the 

procedures in ‘‘SB 747–52A1180’’ when 

the correct reference is ‘‘SB 737– 

52A1180.’’ 

The FAA agrees with the commenter’s 

request. The FAA has added paragraph 

(h)(3) of this AD to clarify the correct 

service information reference. 

Request To Limit the Applicability 

American Airlines (AA) and AIRDO 

requested the FAA limit the 

applicability of the proposed AD to the 

line numbers (L/Ns) identified in the 

effectivity of Boeing Alert Service 

Bulletin 737–52A1180, dated January 

24, 2020. AA stated that because the 

aircraft illustrated parts catalog (IPC) 

does not allow for the unsafe part to be 

installed on aircraft beyond L/N 1075, 

or on the door assemblies allowed to be 

installed on aircraft beyond L/N 1075, 

including all Model 737–600, –700, 

–700C, –800, –900, and –900ER series 

airplanes in the applicability of the 

proposed AD is unnecessarily 

redundant. AIRDO stated Boeing has not 

allowed operators to install P/Ns 

141A6104–3, 141A6150–1, 141A6150– 

2, and 141A6100–678 on airplanes other 

than those with L/N 1–1075 per the IPC 

and related drawings. AIRDO also stated 

that if the fitting or the door assembly 

must be replaced, operators will check 

the IPC and drawing to confirm if the 

affected part number can be used on the 

specific airplane. AIRDO stated that 

based on this general protocol, even 

though the fitting and door assembly are 

physically interchangeable, a suspected 

fitting and door assembly cannot be 

installed on airplanes having L/N 1076 

and subsequent. 

The FAA does not agree with the 

requests to limit the applicability. Both 

the stop fitting assemblies and the doors 

they are installed on are physically 

interchangeable among the airplane 

models listed in the applicability of this 

AD. The FAA has determined it is 

necessary to ensure these rotable parts 

will not be introduced on other 

airplanes by including these airplanes 

in the applicability of this AD. 

Therefore, the FAA has not changed this 

AD in this regard. 

Conclusion 

The FAA reviewed the relevant data, 

considered the comments received, and 

determined that air safety requires 

adopting this AD as proposed. 

Accordingly, the FAA is issuing this AD 

to address the unsafe condition in these 

products. Except for the changes 

described previously, 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 737–52A1180 

RB, dated January 24, 2020. The service 

information specifies procedures for an 

inspection, a measurement, or a records 

check of the upper aft corner stop fitting 

assembly to determine the part number, 

and applicable on-condition actions. 

The on-condition action is to replace the 

affected stop fitting assembly with a 

newly designed stop fitting assembly 

that has improved wall thickness and 

strength. 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. 

Costs of Compliance 

The FAA estimates that this AD 

affects 1,075 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 and part replacement .. Up to 4 work-hours × $85 per hour = Up to $340 ... $4,640 Up to $4,980 .... Up to $5,353,500. 


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Federal Register / Vol. 86, No. 33 / Monday, February 22, 2021 / Rules and Regulations 10443 

The FAA has included all known 

costs in the cost estimate. According to 

the manufacturer, however, some or all 

of the costs of this AD may be covered 

under warranty, thereby reducing the 

cost impact on affected operators. 

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: 

2021–01–04 The Boeing Company: 

Amendment 39–21380; Docket No. 

FAA–2020–0459; Product Identifier 

2020–NM–049–AD. 

(a) Effective Date 

This airworthiness directive (AD) is 

effective March 29, 2021. 

(b) Affected ADs 

None. 

(c) Applicability 

(1) This AD applies to all The Boeing 

Company Model 737 series airplanes, 

excluding Model 737–100, –200, –200C, 

–300, –400, and –500 series airplanes, 

certificated in any category. 

(2) Installation of Supplemental Type 

Certificate (STC) ST00830SE does not affect 

the ability to accomplish the actions required 

by this AD. Therefore, for airplanes on which 

STC ST00830SE is installed, a ‘‘change in 

product’’ alternative method of compliance 

(AMOC) approval request is not necessary to 

comply with the requirements of 14 CFR 

39.17. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 52, Doors. 

(e) Unsafe Condition 

This AD was prompted by reports of 

cracked or completely severed lugs in the 

stop fitting assembly of the forward entry 

door. The FAA is issuing this AD to address 

such cracking or severing, which could result 

in reduced structural integrity of the forward 

entry door and consequent rapid 

decompression of the airplane. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Required Actions 

For airplanes having a date of issuance of 

the original airworthiness certificate or date 

of issuance of the original export certificate 

of airworthiness on or before the effective 

date of this AD: Except as specified by 

paragraph (h) of this AD, at the applicable 

times specified in the ‘‘Compliance’’ 

paragraph of Boeing Alert Requirements 

Bulletin 737–52A1180 RB, dated January 24, 

2020, do all applicable actions identified in, 

and in accordance with, the Accomplishment 

Instructions of Boeing Alert Requirements 

Bulletin 737–52A1180 RB, dated January 24, 

2020. 

Note 1 to paragraph (g): Guidance for 

accomplishing the actions required by this 

AD can be found in Boeing Alert Service 

Bulletin 737–52A1180, dated January 24, 

2020, which is referred to in Boeing Alert 

Requirements Bulletin 737–52A1180 RB, 

dated January 24, 2020. 

(h) Exceptions to Service Information 

Specifications 

(1) Where Boeing Alert Requirements 

Bulletin 737–52A1180 RB, dated January 24, 

2020, uses the phrase ‘‘the original issue date 

of Requirements Bulletin 737–52A1180 RB,’’ 

this AD requires using ‘‘the effective date of 

this AD.’’ 

(2) Where Boeing Alert Requirements 

Bulletin 737–52A1180 RB, dated January 24, 

2020, specifies contacting Boeing for repair 

instructions: This AD requires doing the 

repair before further flight using a method 

approved in accordance with the procedures 

specified in paragraph (j) of this AD. 

(3) Where the heading in Table 1 of the 

Accomplishment Instructions in Boeing Alert 

Requirements Bulletin 737–52A1180 RB, 

dated January 24, 2020, identifies ‘‘SB 747– 

52A1180,’’ the correct reference for this AD 

is ‘‘SB 737–52A1180.’’ 

(i) Parts Installation Prohibition 

No person may install a stop fitting 

assembly with part number 141A6104–3 or a 

forward entry door that has a stop fitting 

assembly with part number 141A6104–3, on 

any airplane, as of the applicable time 

specified in paragraph (i)(1), (2), or (3) of this 

AD. 

(1) For airplanes having an original 

airworthiness certificate or original export 

certificate of airworthiness dated after the 

effective date of this AD: As of the effective 

date of this AD. 

(2) For airplanes on which it is determined 

a stop fitting assembly with part number 

141A6104–3 is not installed, as required by 

paragraph (g) of this AD: After accomplishing 

the inspection, records check, or 

measurement required by paragraph (g) of 

this AD. 

(3) For airplanes on which it is determined 

a stop fitting assembly with part number 

141A6104–3 is installed, as required by 

paragraph (g) of this AD: After accomplishing 

the replacement required by paragraph (g) of 

this AD. 

(j) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, Seattle ACO Branch, 

FAA, has the authority to approve AMOCs 

for this AD, if requested using the procedures 

found in 14 CFR 39.19. In accordance with 

14 CFR 39.19, send your request to your 

principal inspector or 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-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 


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10444 Federal Register / Vol. 86, No. 33 / Monday, February 22, 2021 / Rules and Regulations 

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 Michael Bumbaugh, Aerospace 

Engineer, Airframe Section, FAA, Seattle 

ACO Branch, 2200 South 216th St., Des 

Moines, WA 98198; phone and fax: 206–231– 

3522; email: michael.bumbaugh@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 

737–52A1180 RB, dated January 24, 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 28, 2020. 

Lance T. Gant, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2021–01851 Filed 2–19–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2020–1109; Product 

Identifier 2020–NM–067–AD; Amendment 

39–21383; AD 2021–01–07] 

RIN 2120–AA64 

Airworthiness Directives; The Boeing 

Company Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule; request for 

comments. 

SUMMARY: The FAA is adopting a new 

airworthiness directive (AD) for certain 

The Boeing Company Model 737–700 

series airplanes. This AD requires 

repetitive testing to verify correct 

operation of the smoke clearance mode 

of the equipment cooling system and 

low pressure environmental control 

system, and corrective actions if 

necessary. This AD also requires 

installing new relays and changing the 

wiring to the environmental control 

system, among other actions. This AD 

was prompted by a determination that a 

repetitive test is needed to assess the 

components on airplanes equipped with 

a certain air distribution system 

configuration. The FAA is issuing this 

AD to address the unsafe condition on 

these products. 

DATES: This AD is effective March 9, 

2021. 

The Director of the Federal Register 

approved the incorporation by reference 

of certain publications listed in this AD 

as of March 9, 2021. 

The FAA must receive comments on 

this AD by April 8, 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 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–2020–1109. 

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– 

1109; 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 street address for 

Docket Operations is listed above. 

Comments will be available in the AD 

docket shortly after receipt. 

FOR FURTHER INFORMATION CONTACT: 

Susan L. Monroe, Aerospace Engineer, 

Cabin Safety and Environmental 

Systems Section, FAA, Seattle ACO 

Branch, 2200 South 216th St., Des 

Moines, WA 98198; phone and fax: 206– 

231–3570; email: susan.l.monroe@

faa.gov. 

SUPPLEMENTARY INFORMATION: 

Discussion 

The FAA has determined that a 

repetitive test is needed to assess the 

components on airplanes equipped with 

a certain air distribution system 

configuration. A review by Boeing 

found that there was no maintenance 

procedure available to assess the 

components used to reconfigure the air 

distribution system to the cargo fire 

mode. Without the repetitive test, 

failures of components could be latent 

for extended periods. This condition, if 

not addressed, could result in latent 

failures of the equipment cooling system 

and low pressure environmental control 

system, which, in combination with a 

cargo fire event, could result in smoke 

in the flight deck and/or main cabin, 

and possible loss of aircraft control. 

Other Related Rulemaking 

The FAA issued AD 2016–04–06, 

Amendment 39–18400 (81 FR 9756, 

February 26, 2016) (AD 2016–04–06), 

applicable to all The Boeing Company 

Model 737–600, –700, –700C, –800, 

–900, and –900ER series airplanes. That 

AD requires doing repetitive testing to 

verify correct operation of the 

equipment cooling system and low 

pressure environmental control system, 

and corrective actions if necessary. That 

AD also requires, for certain airplanes, 

installing new relays and changing the 

wiring to the environmental control 

system. That AD was prompted by a 

determination that a repetitive test is 

needed to inspect the components on 

airplanes equipped with a certain air 

distribution system configuration. The 

actions required by that AD are 

intended to address latent failures of the 

equipment cooling system and low 


tkelley on DSKBCP9HB2PROD with RULES