Federal Register / Vol. 86, No. 106 / Friday, June 4, 2021 / Rules and Regulations 29939 

Reserve Bank solely to those 

participating eligible institutions. 

(2) The participating eligible 

institutions in an excess balance 

account shall authorize another 

institution to act as agent of the 

participating institutions for purposes of 

general account management, including 

but not limited to transferring the 

balances of participating institutions in 

and out of the excess balance account. 

An excess balance account must be 

established at the Reserve Bank where 

the agent maintains its master account, 

unless otherwise determined by the 

Board. The agent may not commingle its 

own funds in the excess balance 

account. 

(3) Balances maintained in an excess 

balance account may not be used for 

general payments or other activities. 

(4) Interest on balances of eligible 

institutions maintained in an excess 

balance account is the amount equal to 

the IORB rate in effect on a day 

multiplied by the total balances 

maintained on that day. 

* * * * * 

By order of the Board of Governors of the 

Federal Reserve System. 

Ann Misback, 

Secretary of the Board. 

[FR Doc. 2021–11758 Filed 6–3–21; 8:45 am] 

BILLING CODE 6210–01–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2020–0975; Project 

Identifier 2020–NM–061–AD; Amendment 

39–21566; AD 2021–11–04] 

RIN 2120–AA64 

Airworthiness Directives; De Havilland 

Aircraft of Canada Limited (Type 

Certificate Previously Held by 

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 

De Havilland Aircraft of Canada Limited 

Model DHC–8–400, –401, and –402 

airplanes. This AD was prompted by a 

report of main landing gear (MLG) 

retractions after striking an obstacle or 

severe wheel imbalance after a tire 

failure. This AD requires inspections for 

correct height of the lock link overcenter stop pin and for correct gaps of 

the left-hand and right-hand MLG 

downlock proximity sensors, 

replacement of the shim if necessary, 

corrective actions, and installation of a 

new, improved proximity sensor 

electronic unit (PSEU) with software 

changes. The FAA is issuing this AD to 

address the unsafe condition on these 

products. 

DATES: This AD is effective July 9, 2021. 

The Director of the Federal Register 

approved the incorporation by reference 

of certain publications listed in this AD 

as of July 9, 2021. 

ADDRESSES: For service information 

identified in this final rule, contact De 

Havilland Aircraft of Canada Limited, 

Q-Series Technical Help Desk, 123 

Garratt Boulevard, Toronto, Ontario 

M3K 1Y5, Canada; telephone 416–375– 

4000; fax 416–375–4539; email thd@

dehavilland.com; internet https://

dehavilland.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–2020–0975. 

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– 

0975; 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-nyacocos@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Background 

Transport Canada Civil Aviation 

(TCCA), which is the aviation authority 

for Canada, has issued TCCA AD CF– 

2016–31R1, dated March 24, 2017 

(TCCA AD CF–2016–31R1) (also 

referred to as the Mandatory Continuing 

Airworthiness Information, or the 

MCAI), to correct an unsafe condition 

for certain De Havilland Aircraft of 

Canada Limited Model DHC–8–400, 

–401, and –402 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– 

0975. 

The FAA issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 by adding an AD that would 

apply to certain De Havilland Aircraft of 

Canada Limited Model DHC–8–400, 

–401, and –402 airplanes. The NPRM 

published in the Federal Register on 

November 2, 2020 (85 FR 69276). The 

NPRM was prompted by a report of 

MLG retractions after striking an 

obstacle or severe wheel imbalance after 

a tire failure. The NPRM proposed to 

require inspections for correct height of 

the lock link over-center stop pin and 

for correct gaps of the left-hand and 

right-hand MLG downlock proximity 

sensors, replacement of the shim if 

necessary, corrective actions, and 

installation of a new improved PSEU 

with software changes. The FAA is 

issuing this AD to address loss of MLG 

downlock signal caused by the 

vibrations from those events, which 

leads to de-energizing the MLG solenoid 

sequence valve (SSV) and subsequent 

removal of hydraulic pressure from the 

MLG downlock actuator. Loss of the 

hydraulic pressure in the downlock 

actuator, combined with the vibrations, 

can cause the stabilizer brace to unlock 

and the MLG to subsequently retract. 

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 comments received on the NPRM 

and the FAA’s response to each 

comment. 

Request To Exclude Certain Steps of the 

Accomplishment Instructions of Service 

Information 

Horizon Air requested that paragraphs 

(g), (h), and (i) of the proposed AD be 

revised to require only paragraph 3.B. of 

the Accomplishment Instructions of the 

service bulletins referenced in those 

paragraphs. Horizon Air stated that the 

Job Set-up section (paragraph 3.A.) of 

the Accomplishment Instructions do not 

directly address the unsafe condition. 

Horizon Air also asserted that retaining 

the Job Set-up sections restricts an 

operator’s ability to do other 

maintenance in conjunction with the 

required service bulletins. 

The FAA disagrees with the request to 

exclude paragraph 3.A., Job Set-up, of 

29940 Federal Register / Vol. 86, No. 106 / Friday, June 4, 2021 / Rules and Regulations 

the Accomplishment Instructions from 

this AD’s requirements. The Job Set-up 

sections of the required service bulletins 

include specific procedures for the 

electrical power and proper 

configurations of the nose landing gear 

(NLG) and MLG, which are necessary 

for accomplishing the applicable 

corrective actions on the PSEUs and 

proximity detectors and to prevent 

possible damage to that equipment. 

Requiring the Job Set-up instructions 

should not, in general, restrict the 

ability to schedule other maintenance 

actions in conjunction with the required 

actions. The FAA has not changed this 

AD in this regard. 

Request To Allow Use of Alternative 

Service Information When Installing a 

Certain Part 

Horizon Air requested that paragraph 

(i) of the proposed AD be revised to also 

allow installation of PSEU part number 

(P/N) 30145–0602 in accordance with 

Bombardier Service Bulletin 84–32–143, 

Revision B, dated November 16, 2016. 

Horizon Air pointed out that both 

documents stated that operators may 

receive a PSEU with P/N 30145–0601 or 

30145–0602. Further, Horizon Air noted 

that PSEU P/N 30145–0602 is ‘‘two-way 

interchangeable’’ with P/N 30145–0601, 

and that the installation instructions are 

the same in both service bulletins. 

The FAA disagrees with the request to 

revise paragraph (i) of this AD. The FAA 

agrees that the service information does 

state a two-way interchangeability of 

PSEU P/N 30145–0601 with PSEU P/N 

30145–0602 and that operators may 

receive either PSEU P/N due to 

component availability. However, the 

service information also states that those 

in receipt of a PSEU must declare the 

appropriate service information specific 

to the PSEU P/N. In addition, while 

most of the Accomplishment 

Instructions between Bombardier 

Service Bulletin 84–32–143, Revision B, 

dated November 16, 2016, and 

Bombardier Service Bulletin 84–32–149, 

dated November 16, 2016, are the same, 

they are not identical. Therefore, 

recording compliance with another 

service bulletin would not be in 

compliance with the applicable 

corrective actions for the PSEU P/N. The 

FAA has not changed the AD in this 

regard. 

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 as proposed, except for 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. 

Related Service Information Under 1 

CFR Part 51 

De Havilland Aircraft of Canada 

Limited has issued Bombardier Service 

Bulletin 84–32–140, Revision B, dated 

January 30, 2018. This service 

information describes set-up procedures 

for proper configuration of the MLG 

prior to performing subsequent 

procedures for inspections for correct 

height of the lock link over-center stop 

pin and for correct gaps of the left-hand 

and right-hand MLG downlock 

proximity sensors, and replacement of 

the shim. 

De Havilland Aircraft of Canada 

Limited has also issued Bombardier 

Service Bulletin 84–32–143, Revision B, 

dated November 16, 2016, which 

describes procedures for installation of 

a new, improved PSEU, P/N 30145– 

0601, with software changes. 

De Havilland Aircraft of Canada 

Limited has also issued Bombardier 

Service Bulletin 84–32–149, dated 

November 16, 2016, which describes 

procedures for installation of a new, 

improved PSEU, P/N 30145–0602, with 

software changes. 

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 57 airplanes of U.S. registry. The 

FAA estimates the following costs to 

comply with this AD: 

ESTIMATED COSTS FOR REQUIRED ACTIONS

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

operators 

Up to 12 work-hours × $85 per hour = Up to $1,020 ..... Up to $4,750 ...................... Up to $5,770 ...................... Up to $328,890. 

The FAA estimates the following 

costs to do any necessary on-condition 

actions that would be required based on 

the results of any required actions. The 

FAA has no way of determining the 

number of aircraft that might need these 

on-condition actions: 

ESTIMATED COSTS OF ON-CONDITION ACTIONS

Labor cost Parts cost Cost per 

product 

1 work-hour × $85 per hour = $85 .......................................................................................................................... $374 $459 

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 

Federal Register / Vol. 86, No. 106 / Friday, June 4, 2021 / Rules and Regulations 29941 

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: 

2021–11–04 De Havilland Aircraft of 

Canada Limited (Type Certificate 

Previously Held by Bombardier, Inc.): 

Amendment 39–21566; Docket No. 

FAA–2020–0975; Project Identifier 

2020–NM–061–AD. 

(a) Effective Date 

This airworthiness directive (AD) is 

effective July 9, 2021. 

(b) Affected Airworthiness Directives (ADs) 

None. 

(c) Applicability 

This AD applies to De Havilland Aircraft 

of Canada Limited (type certificate 

previously held by Bombardier, Inc.) Model 

DHC–8–400, –401, and –402 airplanes, 

certificated in any category, having serial 

numbers 4001, and 4003 through 4534 

inclusive. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 32, Landing Gear. 

(e) Reason 

This AD was prompted by a report of main 

landing gear (MLG) retractions after striking 

an obstacle or severe wheel imbalance after 

a tire failure. The FAA is issuing this AD to 

address loss of MLG downlock signal caused 

by the vibrations from those events, which 

leads to de-energizing the MLG solenoid 

sequence valve and subsequent removal of 

hydraulic pressure from the MLG downlock 

actuator. Loss of the hydraulic pressure in 

the downlock actuator, combined with the 

vibrations, can cause the stabilizer brace to 

unlock and the MLG to subsequently retract. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Downlock Sensor Rigging and Reduced 

Lock Link Over-Center 

Within 9 months after the effective date of 

this AD: Verify both the height of the lock 

link over-center stop pin and the gap of the 

left-hand and right-hand MLG downlock 

proximity sensors, and perform corrective 

actions as required, in accordance with 

paragraphs 3.A. and 3.B. of the 

Accomplishment Instructions of Bombardier 

Service Bulletin 84–32–140, Revision B, 

dated January 30, 2018. Do all applicable 

corrective actions before further flight. 

(h) Installation of Proximity Sensor 

Electronic Unit (PSEU) Part Number (P/N) 

30145–0601 

Within 18 months after the effective date 

of this AD, install PSEU P/N 30145–0601 in 

accordance with paragraphs 3.A. and 3.B. of 

the Accomplishment Instructions of 

Bombardier Service Bulletin 84–32–143, 

Revision B, dated November 16, 2016. 

(i) Installation of PSEU P/N 30145–0602 

Installing PSEU P/N 30145–0602 in 

accordance with paragraphs 3.A. and 3.B. of 

the Accomplishment Instructions of 

Bombardier Service Bulletin 84–32–149, 

dated November 16, 2016, also accomplishes 

the requirements of paragraphs (g) and (h) of 

this AD. 

(j) Credit for Previous Actions 

(1) This paragraph provides credit for 

actions required by paragraph (g) of this AD, 

if those actions were performed before the 

effective date of this AD using the service 

information as specified in paragraphs 

(j)(1)(i) or (ii) of this AD. 

(i) Bombardier Service Bulletin 84–32–140, 

dated August 5, 2016. 

(ii) Bombardier Service Bulletin 84–32– 

140, Revision A, dated June 12, 2017. 

(2) This paragraph provides credit for 

actions required by paragraphs (g) and (h) of 

this AD, if PSEU P/N 30145–0601 was 

installed before the effective date of this AD 

using the service information as specified in 

paragraphs (j)(2)(i) or (ii) of this AD. 

(i) Bombardier Service Bulletin 84–32–143, 

dated June 30, 2016. 

(ii) Bombardier Service Bulletin 84–32– 

143, Revision A, dated August 5, 2016. 

(k) Other FAA AD Provisions 

The following provisions also apply to this 

AD: 

(1) Alternative Methods of Compliance 

(AMOCs): The Manager, New York 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 ATTN: Program Manager, 

Continuing Operational Safety, FAA, New 

York ACO Branch, 1600 Stewart Avenue, 

Suite 410, Westbury, NY 11590; telephone 

516–228–7300; fax 516–794–5531. 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. 

(2) Contacting the Manufacturer: For any 

requirement in this AD to obtain instructions 

from a manufacturer, the instructions must 

be accomplished using a method approved 

by the Manager, New York ACO Branch, 

FAA; or Transport Canada Civil Aviation 

(TCCA); or De Havilland Aircraft of Canada 

Limited’s TCCA Design Approval 

Organization (DAO). If approved by the DAO, 

the approval must include the DAOauthorized signature. 

(l) Related Information 

(1) Refer to Mandatory Continuing 

Airworthiness Information (MCAI) TCCA AD 

CF–2016–31R1, dated March 24, 2017, for 

related information. This MCAI may be 

found in the AD docket on the internet at 

https://www.regulations.gov by searching for 

and locating Docket No. FAA–2020–0975. 

(2) For more information about this AD, 

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-avsnyacocos@faa.gov. 

(3) Service information identified in this 

AD that is not incorporated by reference is 

available at the addresses specified in 

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

(m) 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 this AD specifies otherwise. 

(i) Bombardier Service Bulletin 84–32–140, 

Revision B, dated January 30, 2018. 

(ii) Bombardier Service Bulletin 84–32– 

143, Revision B, dated November 16, 2016. 

(iii) Bombardier Service Bulletin 84–32– 

149, dated November 16, 2016. 

(3) For service information identified in 

this AD, contact De Havilland Aircraft of 

Canada Limited, Q-Series Technical Help 

29942 Federal Register / Vol. 86, No. 106 / Friday, June 4, 2021 / Rules and Regulations 

Desk, 123 Garratt Boulevard, Toronto, 

Ontario M3K 1Y5, Canada; telephone 416– 

375–4000; fax 416–375–4539; email thd@

dehavilland.com; internet https://

dehavilland.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 May 27, 2021. 

Ross Landes, 

Deputy Director for Regulatory Operations, 

Compliance & Airworthiness Division, 

Aircraft Certification Service. 

[FR Doc. 2021–11674 Filed 6–3–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2021–0014; Project 

Identifier MCAI–2020–01457–T; Amendment 

39–21573; AD 2021–11–11] 

RIN 2120–AA64 

Airworthiness Directives; Airbus SAS 

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 

Airbus SAS Model A330–200 Freighter 

series airplanes. This AD was prompted 

by a report indicating occurrences of 

broken brackets of the support structure 

of the halon fire extinguishing bottle 

4005WX; investigation showed that 

fatigue cracks initiated in the 

attachment brackets at the cross beams 

due to dynamic loading, and in some 

cases propagated in the struts. This AD 

requires replacing the support brackets 

of the 4005WX fire extinguisher bottle 

with reinforced support brackets, and 

replacing the strut assembly at the 

affected location, as specified in a 

European Union Aviation Safety Agency 

(EASA) AD, which is incorporated by 

reference. The FAA is issuing this AD 

to address the unsafe condition on these 

products. 

DATES: This AD is effective July 9, 2021. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of July 9, 2021. 

ADDRESSES: For material incorporated 

by reference (IBR) in this AD, contact 

EASA, Konrad-Adenauer-Ufer 3, 50668 

Cologne, Germany; telephone +49 221 

8999 000; email ADs@easa.europa.eu; 

internet www.easa.europa.eu. You may 

find this IBR material on the EASA 

website at https://ad.easa.europa.eu. 

You may view this IBR material 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 in the AD docket on 

the internet at https://

www.regulations.gov by searching for 

and locating Docket No. FAA–2021– 

0014. 

Examining the AD Docket 

You may examine the AD docket on 

the internet at https://

www.regulations.gov by searching for 

and locating Docket No. FAA–2021– 

0014; 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: 

Vladimir Ulyanov, Aerospace Engineer, 

Large Aircraft Section, International 

Validation Branch, FAA, 2200 South 

216th St., Des Moines, WA 98198; 

telephone and fax: 206–231–3229; email 

vladimir.ulyanov@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Background 

EASA, which is the Technical Agent 

for the Member States of the European 

Union, has issued EASA AD 2020–0234, 

dated October 27, 2020 (EASA AD 

2020–0234) (also referred to as the 

Mandatory Continuing Airworthiness 

Information, or the MCAI), to correct an 

unsafe condition for certain Airbus SAS 

Model A330–200 Freighter series 

airplanes. 

The FAA issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 by adding an AD that would 

apply to certain Airbus SAS Model 

A330–200 Freighter series airplanes. 

The NPRM published in the Federal 

Register on February 22, 2021 (86 FR 

10498). The NPRM was prompted by a 

report indicating occurrences of broken 

brackets of the support structure of the 

halon fire extinguishing bottle 4005WX; 

investigation showed that fatigue cracks 

initiated in the attachment brackets at 

the cross beams due to dynamic loading, 

and in some cases propagated in the 

struts. The NPRM proposed to require 

replacing the support brackets of the 

4005WX fire extinguisher bottle with 

reinforced support brackets, and 

replacing the strut assembly at the 

affected location, as specified in EASA 

AD 2020–0234. 

The FAA is issuing this AD to address 

fatigue cracking on the attachment 

brackets, which could lead to damage of 

the tubing and electrical wiring of the 

lower deck cargo compartment (LDCC) 

fire extinguishing system, and possibly 

result in insufficient fire suppression 

capability in the LDCC. See the MCAI 

for additional background information. 

Comments 

The FAA gave the public the 

opportunity to participate in developing 

this final rule. The FAA received no 

comments on the NPRM or on the 

determination of the cost to the public. 

Conclusion 

The FAA reviewed the relevant data 

and determined that air safety and the 

public interest require adopting this 

final rule as proposed, except for 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. 

Related Service Information Under 1 

CFR Part 51 

EASA AD 2020–0234 describes 

procedures for replacing the support 

brackets of the 4005WX fire 

extinguisher bottle with reinforced 

support brackets, and replacing the strut 

assembly at the right-hand underfloor 

section 13/14 at frame (FR) 34/35 and 

FR 35/36. This material 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 6 airplanes of U.S. registry. The 

FAA estimates the following costs to 

comply with this AD: