47258 Federal Register / Vol. 86, No. 161 / Tuesday, August 24, 2021 / Proposed Rules 

airplanes, certificated in any category, as 

identified in Boeing Alert Requirements 

Bulletin 737–53A1388 RB, dated October 27, 

2020. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 53, Fuselage. 

(e) Unsafe Condition 

This AD was prompted by an evaluation by 

the design approval holder (DAH) indicating 

that the frame splice between stringer S–13 

and S–14 is subject to widespread fatigue 

damage (WFD). The FAA is issuing this AD 

to address upper frame cracking common to 

the frame splice between stringer S–13 and 

S–14, which could interact with stringer S– 

14 skin lap splice lower fastener row 

cracking in lower skin and result in an 

uncontrolled decompression of the airplane 

and loss of structural integrity. 

(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 737–53A1388 RB, 

dated October 27, 2020, do all applicable 

actions identified in, and in accordance with, 

the Accomplishment Instructions of Boeing 

Alert Requirements Bulletin 737–53A1388 

RB, dated October 27, 2020. 

Note 1 to paragraph (g): Guidance for 

accomplishing the actions required by this 

AD can be found in Boeing Alert Service 

Bulletin 737–53A1388, dated October 27, 

2020, which is referred to in Boeing Alert 

Requirements Bulletin 737–53A1388 RB, 

dated October 27, 2020. 

(h) Exceptions to Service Information 

Specifications 

(1) Where Boeing Alert Requirements 

Bulletin 737–53A1388 RB, dated October 27, 

2020, uses the phrase ‘‘the Original Issue date 

of Requirements Bulletin 737–53A1388 RB,’’ 

this AD requires using ‘‘the effective date of 

this AD,’’ except where Alert Requirements 

Bulletin 737–53A1388 RB, dated October 27, 

2020, uses the phrase ‘‘the Original Issue date 

of Requirements Bulletin 737–53A1388 RB,’’ 

in a note or flag note. 

(2) Where Boeing Alert Requirements 

Bulletin 737–53A1388 RB, dated October 27, 

2020, specifies contacting Boeing for repair 

instructions or for alternative inspections: 

This AD requires doing the repair, or doing 

the alternative inspections and applicable oncondition actions using a method approved 

in accordance with the procedures specified 

in paragraph (i) of this AD. 

(i) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, 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 responsible Flight 

Standards Office, as appropriate. If sending 

information directly to the manager of the 

certification office, send it to the attention of 

the person identified in Related Information. 

Information may be emailed to: 9-ANMLAACO-AMOC-Requests@faa.gov. 

(2) Before using any approved AMOC, 

notify your appropriate principal inspector, 

or lacking a principal inspector, the manager 

of the responsible Flight Standards Office. 

(3) An AMOC that provides an acceptable 

level of safety may be used for any repair, 

modification, or alteration required by this 

AD if it is approved by The Boeing Company 

Organization Designation Authorization 

(ODA) that has been authorized by the 

Manager, 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. 

(j) 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; fax: 562–627–5210; email: wayne.ha@

faa.gov. 

(2) 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. 

Issued on July 26, 2021. 

Lance T. Gant, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2021–18069 Filed 8–23–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2021–0694; Project 

Identifier MCAI–2021–00305–T] 

RIN 2120–AA64 

Airworthiness Directives; De Havilland 

Aircraft of Canada Limited (Type 

Certificate Previously Held by 

Bombardier, Inc.) Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to adopt a 

new airworthiness directive (AD) for De 

Havilland Aircraft of Canada Limited 

Model DHC–8–401 and –402 airplanes. 

This proposed AD was prompted by 

reports of a possible hard contact 

between the #2 top high level sensor 

(HLS) terminal screw head and the #6 

outer wing fuel access panel stiffener 

flange. This proposed AD would require 

removing and replacing or reworking 

the #6 outer wing fuel access panel 

assembly. The FAA is proposing this 

AD to address the unsafe condition on 

these products. 

DATES: The FAA must receive comments 

on this proposed AD by October 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 NPRM, 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. 

Examining the AD Docket 

You may examine the AD docket at 

https://www.regulations.gov by 

searching for and locating Docket No. 

FAA–2021–0694; 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 

NPRM, any comments received, and 

other information. The street address for 

Docket Operations is listed above. 

FOR FURTHER INFORMATION CONTACT: 

Thomas Niczky, Aerospace Engineer, 

Avionics and Electrical Systems 

Section, FAA, New York ACO Branch, 

1600 Stewart Avenue, Suite 410, 

Westbury, NY 11590; telephone 516– 

228–7347; fax 516–794–5531; email 9- 

avs-nyaco-cos@faa.gov. 

SUPPLEMENTARY INFORMATION: 


lotter on DSK11XQN23PROD with PROPOSALS1
Federal Register / Vol. 86, No. 161 / Tuesday, August 24, 2021 / Proposed Rules 47259 

Comments Invited 

The FAA invites you to send any 

written relevant data, views, or 

arguments about this proposal. Send 

your comments to an address listed 

under ADDRESSES. Include ‘‘Docket No. 

FAA–2021–0694; Project Identifier 

MCAI–2021–00305–T’’ at the beginning 

of your comments. The most helpful 

comments reference a specific portion of 

the proposal, explain the reason for any 

recommended change, and include 

supporting data. The FAA will consider 

all comments received by the closing 

date and may amend the proposal 

because of those comments. 

Except for Confidential Business 

Information (CBI) as described in the 

following paragraph, and other 

information as described in 14 CFR 

11.35, the FAA will post all comments 

received, without change, to https://

www.regulations.gov, including any 

personal information you provide. The 

agency will also post a report 

summarizing each substantive verbal 

contact received about this NPRM. 

Confidential Business Information 

CBI is commercial or financial 

information that is both customarily and 

actually treated as private by its owner. 

Under the Freedom of Information Act 

(FOIA) (5 U.S.C. 552), CBI is exempt 

from public disclosure. If your 

comments responsive to this NPRM 

contain commercial or financial 

information that is customarily treated 

as private, that you actually treat as 

private, and that is relevant or 

responsive to this NPRM, it is important 

that you clearly designate the submitted 

comments as CBI. Please mark each 

page of your submission containing CBI 

as ‘‘PROPIN.’’ The FAA will treat such 

marked submissions as confidential 

under the FOIA, and they will not be 

placed in the public docket of this 

NPRM. Submissions containing CBI 

should be sent to Thomas Niczky, 

Aerospace Engineer, Avionics and 

Electrical Systems Section, FAA, New 

York ACO Branch, 1600 Stewart 

Avenue, Suite 410, Westbury, NY 

11590; telephone 516–228–7347; fax 

516–794–5531; email 9-avs-nyaco-cos@

faa.gov. Any commentary that the FAA 

receives which is not specifically 

designated as CBI will be placed in the 

public docket for this rulemaking. 

Background 

Transport Canada Civil Aviation 

(TCCA), which is the aviation authority 

for Canada, has issued TCCA AD CF– 

2021–08, dated March 9, 2021 (TCCA 

AD CF–2021–08) (also referred to after 

this as the Mandatory Continuing 

Airworthiness Information, or the 

MCAI), to correct an unsafe condition 

for De Havilland Aircraft of Canada 

Limited Model DHC–8–401 and –402 

airplanes, serial numbers 4001 and 4003 

through 4628 inclusive. You may 

examine the MCAI in the AD docket at 

https://www.regulations.gov by 

searching for and locating Docket No. 

FAA–2021–0694. 

This proposed AD was prompted by 

the discovery that as a result of build 

tolerances, a hard contact could occur 

between the #2 top HLS terminal screw 

head and the #6 outer wing fuel access 

panel stiffener flange. The FAA is 

proposing this AD to address the 

possibility of electrical arcing during a 

lightning strike, which could be a 

source of ignition inside the fuel tank. 

See the MCAI for additional background 

information. 

Related Service Information Under 1 

CFR Part 51 

De Havilland Aircraft of Canada 

Limited has issued Service Bulletin 84– 

57–35, Revision A, dated February 11, 

2021. This service information describes 

procedures for replacing or reworking 

the #6 outer wing fuel access panel 

assembly. The rework involves an eddy 

current or fluorescent liquid penetrant 

inspection of the rework area for crack 

indications. 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. 

FAA’s Determination 

This product has been approved by 

the aviation authority of another 

country, and is approved for operation 

in the United States. Pursuant to the 

FAA’s bilateral agreement with the State 

of Design Authority, the FAA has been 

notified of the unsafe condition 

described in the MCAI and service 

information referenced above. The FAA 

is proposing this AD because the FAA 

evaluated all the relevant information 

and determined the unsafe condition 

described previously is likely to exist or 

develop on other products of the same 

type design. 

Proposed AD Requirements in This 

NPRM 

This proposed AD would require 

accomplishing the actions specified in 

the service information already 

described. 

Costs of Compliance 

The FAA estimates that this AD, if 

adopted as proposed, would affect 54 

airplanes of U.S. registry. For either 

replacement or repair of the #6 outer 

wing fuel access panel, depending on 

the option selected by the operator to 

comply with this proposed AD, the FAA 

estimates the following costs: 

ESTIMATED COSTS

Action Labor cost Parts cost Cost per 

product 

Replacement ................................ Up to 10 work-hours × $85 per hour = Up to $850 ......................... Up to $16,430 ...... Up to $17,280. 

Repair .......................................... 13 work-hours × $85 per hour = $1,105 .......................................... $49 ....................... $1,154. 

The FAA has included all known 

costs in its cost estimate. According to 

the manufacturer, however, some or all 

of the costs of this proposed 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. 


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47260 Federal Register / Vol. 86, No. 161 / Tuesday, August 24, 2021 / Proposed Rules 

Regulatory Findings 

The FAA determined that this 

proposed AD would not have federalism 

implications under Executive Order 

13132. This proposed AD would 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 this proposed regulation: 

(1) Is not a ‘‘significant regulatory 

action’’ under Executive Order 12866, 

(2) Would not affect intrastate 

aviation in Alaska, and 

(3) Would 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 Proposed Amendment 

Accordingly, under the authority 

delegated to me by the Administrator, 

the FAA proposes to amend 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: 

De Havilland Aircraft of Canada Limited 

(Type Certificate Previously Held by 

Bombardier, Inc.): Docket No. FAA– 

2021–0694; Project Identifier MCAI– 

2021–00305–T. 

(a) Comments Due Date 

The FAA must receive comments on this 

airworthiness directive (AD) by October 8, 

2021. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to De Havilland Aircraft 

of Canada Limited Model DHC–8–401 and 

–402 airplanes, certificated in any category, 

serial numbers 4001 and 4003 through 4628 

inclusive. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 57, Wings. 

(e) Unsafe Condition 

This AD was prompted by reports of a 

possible hard contact between the #2 top 

high level sensor (HLS) terminal screw head 

and the #6 outer wing fuel access panel 

stiffener flange. The FAA is issuing this AD 

to address the possibility of electrical arcing 

during a lightning strike, which could be a 

source of ignition inside the fuel tank. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Required Actions 

Within 8,000 flight hours after the effective 

date of this AD: Do the actions specified in 

paragraph (g)(1) or (2) of this AD. 

(1) Replace the #6 outer wing fuel access 

panel assembly in accordance with Section 

3.B., Part A, of the Accomplishment 

Instructions of De Havilland Aircraft of 

Canada Limited Service Bulletin 84–57–35, 

Revision A, dated February 11, 2021. 

(2) Rework the #6 outer wing fuel access 

panel assembly, including an eddy current or 

fluorescent liquid penetrant inspection for 

crack indications of the rework area, in 

accordance with Section 3.B., Part B, of the 

Accomplishment Instructions of De 

Havilland Aircraft of Canada Limited Service 

Bulletin 84–57–35, Revision A, dated 

February 11, 2021. If any crack indication is 

found, before further flight, repair using a 

method approved in accordance with the 

procedures specified in paragraph (j)(2) of 

this AD. 

(h) Parts Installation Prohibition 

As of the effective date of this AD, no 

person may install a #6 outer wing fuel 

access panel assembly, part numbers (P/Ns) 

85714233–003/–004 and 85714233–005/– 

006, on any airplane. 

(i) Credit for Previous Actions 

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 De Havilland Aircraft 

of Canada Limited Service Bulletin 84–57– 

35, dated October 1, 2020. 

(j) 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 

responsible Flight Standards 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 

responsible Flight Standards 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. 

(k) Related Information 

(1) Refer to Mandatory Continuing 

Airworthiness Information (MCAI) TCCA AD 

CF–2021–08, dated March 9, 2021, 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–2021–0694. 

(2) For more information about this AD, 

contact Thomas Niczky, Aerospace Engineer, 

Avionics and Electrical Systems Section, 

FAA, New York ACO Branch, 1600 Stewart 

Avenue, Suite 410, Westbury, NY 11590; 

telephone 516–228–7347; fax 516–794–5531; 

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

(3) For service information identified in 

this AD, 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. 

Issued on August 18, 2021. 

Gaetano A. Sciortino, 

Deputy Director for Strategic Initiatives, 

Compliance & Airworthiness Division, 

Aircraft Certification Service. 

[FR Doc. 2021–18111 Filed 8–23–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2021–0665; Project 

Identifier AD–2021–00270–T] 

RIN 2120–AA64 

Airworthiness Directives; The Boeing 

Company Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to 

supersede Airworthiness Directive (AD) 

2017–23–02, which applies to certain 

The Boeing Company Model 737–200, 

–200C, –300, –400, and –500 series 

airplanes. AD 2017–23–02 requires 


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