10776 Federal Register / Vol. 86, No. 34 / Tuesday, February 23, 2021 / Rules and Regulations 

work-hours per product to comply with 

the requirements of this AD. The 

average labor rate is $85 per work-hour. 

Required parts will cost about $75 per 

product. 

Based on these figures, the FAA 

estimates the cost of this AD on U.S. 

operators at $63,900, or $1,775 per 

product. 

The FAA has included all costs in this 

cost estimate. According to the 

manufacturer, however, some 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. 

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: 

2021–01–05 Pilatus Aircraft Ltd.: 

Amendment 39–21381; Docket No. 

FAA–2020–0818; Project Identifier 

MCAI–2020–00987–A. 

(a) Effective Date 

This airworthiness directive (AD) is 

effective March 30, 2021. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to Pilatus Aircraft Ltd. 

Model PC–24 airplanes, serial numbers 101 

through 160 inclusive, certificated in any 

category. 

(d) Subject 

Joint Aircraft System Component (JASC) 

Code 2497, ELECTRICAL POWER SYSTEM 

WIRING; 3197, INSTRUMENT SYSTEM 

WIRING. 

(e) Unsafe Condition 

This AD was prompted by electrical 

harness installations on some PC–24 

airplanes in production that did not comply 

with the approved design. The FAA is 

issuing this AD to prevent wire chafing and 

potential arcing or failure of wires having the 

incorrect length. The unsafe condition, if not 

addressed, could result in loss of system 

redundancy, electrical arcing, or loss of 

power plant fire protection. 

(f) Actions and Compliance 

Unless already accomplished, during the 

next annual inspection after the effective date 

of this AD or within 12 months after the 

effective date of this AD, whichever occurs 

later, modify the electrical harness 

installation in accordance with sections 3.A. 

through 3.H. of the Accomplishment 

Instructions in Pilatus PC–24 Service 

Bulletin No. 91–001, dated April 7, 2020. 

(g) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, International Validation 

Branch, FAA, has the authority to approve 

AMOCs for this AD, if requested using the 

procedures found in 14 CFR 39.19. Send 

information to Doug Rudolph, Aerospace 

Engineer, FAA, General Aviation & Rotorcraft 

Section, International Validation Branch, 901 

Locust, Room 301, Kansas City, Missouri 

64106; phone: (816) 329–4059; fax: (816) 

329–4090; email: doug.rudolph@faa.gov. 

(2) Before using any approved AMOC on 

any airplane to which the AMOC applies, 

notify your appropriate principal inspector 

(PI) in the FAA Flight Standards District 

Office (FSDO), or lacking a PI, your local 

FSDO. 

(h) Related Information 

(1) Refer to European Union Aviation 

Safety Agency (EASA) AD No. 2020–0158, 

dated July 16, 2020, for more information. 

You may examine the EASA AD at https:// 

www.regulations.gov by searching for and 

locating Docket No. FAA–2020–0818. 

(i) Material Incorporated by Reference 

(1) The Director of the Federal Register 

approved the incorporation by reference 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) Pilatus PC–24 Service Bulletin No. 91– 

001, dated April 7, 2020. 

(ii) [Reserved] 

(3) For Pilatus Aircraft Ltd service 

information identified in this AD, contact 

Pilatus Aircraft Ltd., CH–6371, Stans, 

Switzerland; phone: +41 848 24 7 365; email: 

techsupport.ch@pilatus-aircraft.com; 

website: http://www.pilatus-aircraft.com/. 

(4) You may view this service information 

at FAA, Airworthiness Products Section, 

Operational Safety Branch, 901 Locust, 

Kansas City, Missouri 64106. For information 

on the availability of this material at the 

FAA, call (816) 329–4148. 

(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/ 

ibr-locations.html. 

Issued on December 30, 2020. 

Lance T. Gant, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2021–03511 Filed 2–22–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2019–0705; Product 

Identifier 2019–NM–098–AD; Amendment 

39–21396; AD 2021–02–13] 

RIN 2120–AA64 

Airworthiness Directives; The Boeing 

Company Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

Federal Register / Vol. 86, No. 34 / Tuesday, February 23, 2021 / Rules and Regulations 10777 

SUMMARY: The FAA is adopting a new 

airworthiness directive (AD) for certain 

The Boeing Company Model 737–600, 

–700, –700C, –800, and –900 series 

airplanes. This AD was prompted by 

reports of cracks in the bear strap from 

station (STA) 290 to STA 296, and 

between stringers S–8R and S–9R, 

sometimes common to fasteners in the 

gap cover and emanating from rough 

sanding marks found on the surface of 

the bear strap. This AD requires 

inspections of the fuselage skin and bear 

strap at the forward galley door between 

certain stations for cracks, and 

applicable on-condition actions. The 

FAA is issuing this AD to address the 

unsafe condition on these products. 

DATES: This AD is effective March 30, 

2021. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of March 30, 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; 

phone: 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–2019–0705. 

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–2019– 

0705; 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 certain The Boeing Company 

Model 737–600, –700, –700C, –800, and 

–900 series airplanes. The NPRM 

published in the Federal Register on 

October 1, 2019 (84 FR 52047). The 

NPRM was prompted by reports of 

cracks in the bear strap between certain 

stations, sometimes common to 

fasteners in the gap cover and 

emanating from rough sanding marks 

found on the surface of the bear strap. 

The NPRM proposed to require 

inspections of the fuselage skin and bear 

strap at the forward galley door between 

certain stations for cracks, and 

applicable on-condition actions. 

The FAA issued a supplemental 

NPRM (SNPRM) to amend 14 CFR part 

39 by adding an AD that would apply 

to certain The Boeing Company Model 

737–600, –700, –700C, –800, and –900 

series airplanes. The SNPRM published 

in the Federal Register on May 1, 2020 

(85 FR 25348). The FAA issued the 

SNPRM to revise certain inspections to 

provide the correct thickness callouts 

for the fuselage skin and bear strap. 

The FAA is issuing this AD to address 

cracking of the bear strap, which could 

result in severing of the bear strap, 

possibly leading to uncontrolled 

decompression and loss of structural 

integrity of the airplane. 

Comments 

The FAA gave the public the 

opportunity to participate in developing 

this final rule. The following presents 

the comments received on the SNPRM 

and the FAA’s response to each 

comment. 

Support for the SNPRM 

United Airlines stated that it has no 

technical objection to the SNPRM and 

that it concurs with the proposed 

rulemaking. 

Request for an Alternative Method of 

Compliance for a Certain Repair 

Southwest Airlines (SWA) requested 

that the Boeing 737–700/-800 Structural 

Repair Manual (SRM) 53–10–01, Repair 

6, be approved as an alternative method 

of compliance (AMOC) to certain 

corrective actions specified in Boeing 

Alert Requirements Bulletin 737– 

53A1383 RB, Revision 1, dated February 

19, 2020. SWA contended that this 

repair covers the affected inspection 

zone, and that this SRM repair should 

be a terminating action to the 

inspections specified in Boeing Alert 

Requirements Bulletin 737–53A1383 

RB, Revision 1, dated February 19, 2020, 

because the entire inspection area 

covered is common to the repair given 

in Boeing 737–700/-800 SRM 53–10–01, 

Repair 6. SWA asserted that operators 

should be able to accomplish this SRM 

repair without contacting Boeing, 

provided there are no deviations and 

that the findings meet the criteria listed 

in the Boeing 737–700/-800 SRM 53– 

10–01, Repair 6. SWA also noted that 

the SRM was published after Boeing 

Alert Requirements Bulletin 737– 

53A1383 RB, Revision 1, dated February 

19, 2020, so there was no way to 

reference the SRM repair within it. 

The FAA disagrees with the request 

because the referenced SRM repair has 

not yet been approved for the specified 

conditions. However, under the 

provisions of paragraph (j) of this AD, 

the FAA will consider requests for 

approval of an AMOC if a proposal is 

submitted that is supported by technical 

data indicating that the proposed repair 

will provide an acceptable level of 

safety. If the referenced SRM repair is 

determined to be acceptable to address 

the specified conditions, the FAA may 

approve, and Boeing may issue, a global 

AMOC for the SRM repair. The FAA has 

not changed this AD as a result of this 

comment. 

Request for an Altered Compliance 

Time for Condition 1, Action 1, of the 

Service Information 

Southwest Airlines requested that 

where table 1 of paragraph 1.E., 

‘‘Compliance,’’ of Boeing Alert 

Requirements Bulletin 737–53A1383 

RB, Revision 1, dated February 19, 2020, 

states a compliance time of ‘‘Before 

further flight’’ for certain on-condition 

actions, the proposed AD should specify 

this compliance time as ‘‘Before 15,000 

total flight cycles or within 6,000 flight 

cycles after the original issue of the AD, 

whichever occurs later.’’ Southwest 

Airlines also requested that the FAA 

clarify the requirement of Condition 1, 

Action 1, and Condition 3 and 

Condition 4.1.1, within Boeing Alert 

Requirements Bulletin 737–53A1383 

RB, Revision 1, dated February 19, 2020, 

paragraph 1.E., ‘‘Compliance,’’ in Tables 

1 and 2, to do the alternative 

inspections and applicable on-condition 

action(s) before further flight. SWA 

asserted that there is an equivalent level 

of safety between an airplane without a 

repair reaching the compliance time 

threshold to perform the Boeing service 

bulletin inspection and an airplane with 

a repair reaching the compliance time 

threshold before an action is required. 

Therefore, the compliance times for 

obtaining the alternative inspection(s) 

for the existing repairs should align 

with the compliance times allowed for 

10778 Federal Register / Vol. 86, No. 34 / Tuesday, February 23, 2021 / Rules and Regulations 

the initial service bulletin general visual 

inspection in lieu of ‘‘before further 

flight.’’ SWA proposed that this 

allowance be listed within paragraph (h) 

of the proposed AD, similar to the 

allowance provided by paragraph (i) of 

the proposed AD. 

The FAA agrees that allowing the AD 

compliance time for an airplane with an 

existing repair to be the same as an 

aircraft without an existing repair will 

provide an acceptable level of safety. 

Any alternative inspection program 

including compliance times must be 

done in accordance with an approved 

AMOC. The FAA has added paragraph 

(h)(3) of this AD to address this change. 

Request To Clarify Authority for 

Approval of Alternative Inspection 

Programs 

Southwest Airlines requested that the 

FAA clarify who has the authority to 

approve an alternative inspection 

program for any repair found during 

Boeing Alert Requirements Bulletin 

737–53A1383 RB, Revision 1, dated 

February 19, 2020, paragraph 1.E, 

‘‘Compliance,’’ Table 1, Condition 1, 

Action 1. Paragraph (j)(1) of the 

proposed AD clearly indicated that the 

manager of the Seattle ACO Branch has 

that authority; paragraph (j)(3) of the 

proposed AD provided the path to 

obtain an AMOC by The Boeing 

Company Organization Designation 

Authorization (ODA) as delegated only 

for a repair, modification, and 

alteration. SWA requested clarification 

whether paragraph (j)(3) of the proposed 

AD encompasses both existing repairs 

and repairs installed as a result of 

inspection findings. SWA asserted that 

it is unclear whether the reference to the 

repair is for an existing repair that is 

located in the inspection area or for a 

repair that is installed as a result of any 

crack finding. 

The FAA agrees to clarify. The Boeing 

Company ODA has authority to approve 

AMOCs as authorized and delegated for 

repairs installed prior to the AD and 

repairs due to a crack finding, as well 

as repairs not due to a crack finding. An 

operator would need to provide The 

Boeing Company ODA with all details 

and geometry needed to design and 

analyze the repair data. 

Request To Clarify the Use of ‘‘Covers’’ 

in the Service Information 

SWA commented that Boeing Alert 

Requirements Bulletin 737–53A1383 

RB, Revision 1, dated February 19, 2020, 

paragraph 1.E., ‘‘Compliance,’’ Table 1, 

note (b), omits the inspection in areas 

where a repair covers the affected zone, 

provided conditions 1 and 2 are met. A 

similar note is included in paragraph 

1.E., ‘‘Compliance,’’ Table 2, note (c). 

SWA would like clarification of the 

word ‘‘covers’’ as it relates to repairs in 

the area. Since the configuration has 

changed because of the repair, SWA 

stated that the repair’s damage tolerance 

program provides an equivalent level of 

safety for this area. 

The FAA has coordinated with Boeing 

to clarify the intent of the wording in 

this section. Note (b) in Table 1 and note 

(c) in Table 2 of Boeing Alert 

Requirements Bulletin 737–53A1383 

RB, Revision 1, dated February 19, 2020, 

paragraph 1.E., ‘‘Compliance,’’ apply to 

the area ‘‘covered by’’ a repair, but not 

for the area ‘‘common to’’ a repair. A 

repair that is ‘‘common to’’ the area, 

meaning physically in the same area as 

the NPRM-proposed repair, but that was 

not meant to address the issue specified 

in the NPRM (i.e., ‘‘covered’’ areas), 

could potentially be obscuring the 

inspections that would detect crack 

growth which this AD is meant to 

mitigate. Therefore, if a repair was not 

done as a corrective action for a crack 

in the bear strap, and the operator does 

not perform the inspections specified in 

the Boeing Alert Requirements Bulletin 

737–53A1383 RB, Revision 1, dated 

February 19, 2020, it may result in the 

unsafe condition. The FAA has not 

changed this AD as a result of this 

comment. 

Request To Include Inspection 

Programs 

SWA commented that paragraph (j)(3) 

of the proposed AD (in the SNPRM) 

stated that an AMOC may be used for 

any required repair, modification, or 

alteration if approved by The Boeing 

Company ODA. SWA stated that 

inspection programs should be included 

in this list of conditions for which The 

Boeing Company ODA can provide an 

AMOC, as paragraph (h)(2) explicitly 

states it is acceptable to accomplish 

alternative inspections approved in 

accordance with the procedures 

specified in paragraph (j) of the 

proposed AD. 

The FAA agrees with the assertion 

that the inspection program may be part 

of the AMOC because the inspection 

program for the repaired area may be 

part of the repair, which in turn is part 

of the AMOC. However, the FAA 

disagrees with changing this AD 

because an AMOC issued for a repair 

will include the inspection program. 

The request to add certain inspection 

programs to The Boeing Company ODAauthorized list of AMOC approvals is 

outside the scope of this rulemaking. 

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 and the 

public interest require adopting this 

final rule with the change described 

previously and minor editorial changes. 

The FAA has determined that these 

minor changes: 

• Are consistent with the intent that 

was proposed in the SNPRM for 

addressing the unsafe condition; and 

• Do not add any additional burden 

upon the public than was already 

proposed in the SNPRM. 

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 737–53A1383 

RB, Revision 1, dated February 19, 2020. 

This service information describes 

procedures for inspecting for cracks of 

the fuselage skin and bear strap at the 

forward galley door between certain 

stations, through the use of two 

alternative inspection methods for the 

initial inspections: (1) Internal and 

external general visual inspections and 

internal surface high frequency eddy 

current (HFEC) inspections, and (2) 

external general visual and external 

eddy current inspections. This service 

information also describes procedures 

for applicable on-condition actions 

including inspections for cracks, HFEC 

inspections for cracks, low frequency 

eddy current (LFEC) inspections for 

cracks, and repair, depending on the 

inspection method selected. 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 752 airplanes of U.S. registry. 

The FAA estimates the following costs 

to comply with this AD: 

Federal Register / Vol. 86, No. 34 / Tuesday, February 23, 2021 / Rules and Regulations 10779 

ESTIMATED COSTS FOR REQUIRED ACTIONS: OPTION 1 

Action Labor cost Parts cost Cost per 

product 

Cost on U.S. 

operators 

Internal general visual inspection ........... 11 work-hours × $85 per hour = $935 ... $0 $935 ....................... $703,120. 

External general visual inspection ......... 1 work-hour × $85 per hour = $85 ........ 0 85 ........................... 63,920. 

Internal Surface HFEC inspections ........ 3 work-hours × $85 per hour = $255 

per inspection cycle.

0 255 per inspection 

cycle.

191,760 per inspection cycle. 

ESTIMATED COSTS FOR REQUIRED ACTIONS: OPTION 2 

Action Labor cost Parts cost Cost per 

product 

Cost on U.S. 

operators 

External general visual inspection ......... 1 work-hour × $85 per hour = $85 ........ $0 $85 ......................... $63,920. 

External LFEC and HFEC inspections ... 18 work-hours × $85 per hour = $1,530 

per inspection cycle.

0 1,530 per inspection cycle.1,150,560 per inspection cycle. 

The FAA has received no definitive 

data that would enable the agency to 

provide cost estimates for the oncondition actions specified in this AD. 

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. 

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: 

2021–02–13 The Boeing Company: 

Amendment 39–21396; Docket No. 

FAA–2019–0705; Product Identifier 

2019–NM–098–AD. 

(a) Effective Date 

This airworthiness directive (AD) is 

effective March 30, 2021. 

(b) Affected ADs 

None. 

(c) Applicability 

(1) This AD applies to The Boeing 

Company Model 737–600, –700, –700C, 

–800, and –900 series airplanes, certificated 

in any category, as identified in Boeing Alert 

Requirements Bulletin 737–53A1383 RB, 

Revision 1, dated February 19, 2020. 

(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 53, Fuselage. 

(e) Unsafe Condition 

This AD was prompted by reports of cracks 

in the bear strap from station (STA) 290 to 

STA 296, and between stringers S–8R and S– 

9R, sometimes common to fasteners in the 

gap cover and emanating from rough sanding 

marks found on the surface of the bear strap. 

The FAA is issuing this AD to address 

cracking of the bear strap, which could result 

in severing of the bear strap, possibly leading 

to uncontrolled decompression and loss of 

structural integrity of the airplane. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Required Actions 

Except as specified by paragraph (h) of this 

AD: At the applicable times specified in the 

‘‘Compliance’’ paragraph of Boeing Alert 

Requirements Bulletin 737–53A1383 RB, 

Revision 1, dated February 19, 2020, do all 

applicable actions identified in, and in 

accordance with, the Accomplishment 

Instructions of Boeing Alert Requirements 

Bulletin 737–53A1383 RB, Revision 1, dated 

February 19, 2020. 

Note 1 to paragraph (g): Guidance for 

accomplishing the actions required by this 

AD can be found in Boeing Alert Service 

Bulletin 737–53A1383, Revision 1, dated 

February 19, 2020, which is referred to in 

Boeing Alert Requirements Bulletin 737– 

53A1383 RB, Revision 1, dated February 19, 

2020. 

(h) Exceptions to Service Information 

Specifications 

(1) Where Boeing Alert Requirements 

Bulletin 737–53A1383 RB, Revision 1, dated 

February 19, 2020, uses the phrase ‘‘the 

original issue date of Requirements Bulletin 

737–53A1383 RB,’’ this AD requires using 

‘‘the effective date of this AD,’’ except where 

Boeing Alert Requirements Bulletin 737– 

53A1383 RB, Revision 1, dated February 19, 

10780 Federal Register / Vol. 86, No. 34 / Tuesday, February 23, 2021 / Rules and Regulations 

2020, uses the phrase ‘‘the original issue date 

of Requirements Bulletin 737–53A1383 RB’’ 

in a note or flag note. 

(2) Where Boeing Alert Requirements 

Bulletin 737–53A1383 RB, Revision 1, dated 

February 19, 2020, specifies contacting 

Boeing for repair instructions or for 

alternative inspections: This AD requires 

doing the repair, or doing the alternative 

inspections and applicable on-condition 

actions, using a method and compliance time 

approved in accordance with the procedures 

specified in paragraph (j) of this AD. 

(3) Where Boeing Alert Requirements 

Bulletin 737–53A13833 RB, Revision 1, dated 

February 19, 2020, in Tables 1 and 2, 

Condition 1 (Action 1), Condition 3, and 

Condition 4.1.1 (Action 1), specifies a 

compliance time of ‘‘before further flight’’: 

This AD requires compliance before 15,000 

total flight cycles or within 6,000 flight 

cycles after the effective date of this AD, 

whichever occurs later. 

(i) Credit for Previous Actions 

This paragraph provides credit for the 

actions specified in paragraph (g) of this AD, 

if those actions were performed before the 

effective date of this AD, using Boeing Alert 

Requirements Bulletin 737–53A1383 RB, 

dated May 9, 2019, except for airplanes on 

which Option 2, Condition 4, has been done. 

For airplanes on which Option 2, Condition 

4, has been done, credit is given for Boeing 

Alert Requirements Bulletin 737–53A1383 

RB, dated May 9, 2019, provided operators 

do the external low frequency eddy current 

(LFEC) inspection of the forward galley door 

bear strap and external high frequency eddy 

current (HFEC) inspection of the fuselage 

skin for any crack in accordance with Figure 

4 of the Accomplishment Instructions of 

Boeing Alert Requirements Bulletin 737– 

53A1383 RB, Revision 1, dated February 19, 

2020. The compliance time for 

accomplishing these actions is at the later of 

the times specified in paragraphs (i)(1) and 

(2) of this AD. Except as specified in 

paragraph (h)(3), do all applicable oncondition actions identified in, and in 

accordance with, the Accomplishment 

Instructions of Boeing Alert Requirements 

Bulletin 737–53A1383 RB, Revision 1, dated 

February 19, 2020, at the applicable times 

specified in the ‘‘Compliance’’ paragraph of 

Boeing Alert Requirements Bulletin 737– 

53A1383 RB, Revision 1, dated February 19, 

2020. 

(1) Before 15,000 total flight cycles. 

(2) Within 6,000 flight cycles after the 

effective date 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, 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 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 

737–53A1383 RB, Revision 1, dated February 

19, 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; 

phone: 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 January 14, 2021. 

Gaetano A. Sciortino, 

Deputy Director for Strategic Initiatives, 

Compliance & Airworthiness Division, 

Aircraft Certification Service. 

[FR Doc. 2021–03572 Filed 2–22–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2020–0331; Product 

Identifier 2020–NM–019–AD; Amendment 

39–21397; AD 2021–02–14] 

RIN 2120–AA64 

Airworthiness Directives; The Boeing 

Company Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: The FAA is adopting a new 

airworthiness directive (AD) for certain 

The Boeing Company Model 737–600, 

–700, –700C, –800, –900, and –900ER 

series airplanes. This AD was prompted 

by a report that the necessary sealant 

was not applied to the side of body 

(SOB) slot as a result of a production 

drawing that provided unclear SOB slot 

sealant application instructions. This 

AD requires a general visual inspection 

for insufficient sealant in the SOB slot, 

and related investigative and corrective 

actions. The FAA is issuing this AD to 

address the unsafe condition on these 

products. 

DATES: This AD is effective March 30, 

2021. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of March 30, 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–2020–0331. 

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– 

0331; 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