This section of the FEDERAL REGISTER

contains regulatory documents having general

applicability and legal effect, most of which

are keyed to and codified in the Code of

Federal Regulations, which is published under

50 titles pursuant to 44 U.S.C. 1510.

The Code of Federal Regulations is sold by

the Superintendent of Documents.

Rules and Regulations Federal Register

77495 

Vol. 88, No. 217 

Monday, November 13, 2023 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2023–0436; Project 

Identifier AD–2022–00395–T; Amendment 

39–22581; AD 2023–21–09] 

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 777–200, 777– 

200LR, 777–300, 777–300ER, and 777F 

series airplanes. This AD was prompted 

by a report of a ‘‘FLAPS DRIVE’’ caution 

message in flight due to the torque trip 

indicator of the No. 2 trailing edge (TE) 

flap transmission assembly being in the 

set position, which resulted in an air 

turn-back. This AD requires an 

inspection or records review to 

determine the serial numbers of the TE 

flap transmission and gearbox 

assemblies, and applicable on-condition 

corrective actions. This AD also limits 

the installation of affected parts. The 

FAA is issuing this AD to address the 

unsafe condition on these products. 

DATES: This AD is effective December 

18, 2023. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of December 18, 2023. 

ADDRESSES: 

AD Docket: You may examine the AD 

docket at regulations.gov under Docket 

No. FAA–2023–0436; 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. 

Material Incorporated by Reference: 

• 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; website 

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 at 

regulations.gov under Docket No. FAA– 

2023–0436. 

FOR FURTHER INFORMATION CONTACT: 

Anthony Caldejon, Aviation Safety 

Engineer, FAA, 2200 South 216th St., 

Des Moines, WA 98198; telephone: 206– 

231–3534; email: anthony.v.caldejon@

faa.gov. 

SUPPLEMENTARY INFORMATION: 

Background 

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 

777–200, 777–200LR, 777–300, 777– 

300ER, and 777F series airplanes. The 

NPRM published in the Federal 

Register on April 6, 2023 (88 FR 20433). 

The NPRM was prompted by a report of 

a ‘‘FLAPS DRIVE’’ caution message in 

flight due to the torque trip indicator of 

the No. 2 TE flap transmission assembly 

being in the set position, which resulted 

in an air turn-back. In the NPRM, the 

FAA proposed to require an inspection 

or records review to determine the serial 

numbers of the TE flap transmission and 

gearbox assemblies, and applicable oncondition corrective actions. The FAA 

also proposed to limit the installation of 

affected parts. The FAA is issuing this 

AD to address a broken ratchet pawl 

assembly in combination with an 

upstream torque tube disconnect, which 

can cause failure of the no-back brake to 

hold flap surfaces in a commanded 

position, and possible debris in the 

transmission assembly, which can 

prevent the pawl from engaging the 

ratchet plate or cause other damage to 

the transmission assembly. The unsafe 

condition, if not addressed, could result 

in asymmetric loss of the lift that can 

prevent continued safe flight and 

landing. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received comments from 

Boeing and the Air Line Pilots 

Association, International (ALPA) who 

supported the NPRM without change. 

The FAA received additional 

comments from four commenters, 

including Air France Industries, China 

Eastern Tech, FedEx, and United 

Airlines (United). FedEx and United 

supported the NPRM and had additional 

comments. The following presents the 

comments received on the NPRM and 

the FAA’s response to each comment. 

Request To Allow Installation of 

Additional Parts 

China Eastern Tech, FedEx, and 

United requested that paragraph (j) of 

the proposed AD be revised to allow 

installation of parts on which the 

inspection and applicable corrective 

actions have been accomplished in 

accordance with Boeing Alert 

Requirements Bulletin 777–27A0123 

RB, dated October 11, 2021. 

The FAA agrees with the commenters’ 

request. Paragraph (i) of this AD allows 

credit for actions accomplished using 

Boeing Alert Requirements Bulletin 

777–27A0123 RB, dated October 11, 

2021. Therefore, the FAA has 

determined that it is also acceptable to 

allow installation of parts on which, 

prior to the effective date of this AD, the 

inspection and applicable corrective 

actions have been accomplished as 

specified in Boeing Alert Requirements 

Bulletin 777–27A0123 RB, dated 

October 11, 2021. The FAA has revised 

paragraph (j) of this AD accordingly. 

Request To Specify That the AD Is 

Applicable to the Component 

Air France Industries requested that 

the FAA specify that the service 

information and proposed AD are 

applicable to the component (assembly), 

regardless of the component’s 

installation status. The commenter 

stated that this would clarify the work 

of operators and shops and prevent 

shops from providing airlines with a 

replacement part on which the actions 


khammond on DSKJM1Z7X2PROD with RULES
77496 Federal Register / Vol. 88, No. 217 / Monday, November 13, 2023 / Rules and Regulations 

specified in the proposed AD have not 

been accomplished. Air France 

Industries noted that the proposed AD 

does not provide instructions for spare 

parts. 

The FAA disagrees with the 

commenter’s request. When the unsafe 

condition results from the installation of 

the appliance or part on an aircraft, the 

AD action is issued against the aircraft, 

not the appliance or part. In this case, 

the affected assemblies are rotable parts, 

so it is possible that an affected 

assembly could be installed on 

numerous airplanes during its service 

life. Paragraph (j) of this AD prohibits 

the installation of an affected assembly 

on an airplane, unless the actions 

specified in the service information 

have been accomplished on that 

assembly. Therefore, no change to this 

AD is necessary. 

Request To Standardize Part Tracking 

Method 

United and FedEx requested that the 

proposed AD be revised to specify a 

different method of marking parts on 

which the service information has been 

accomplished. United noted that the 

service information specifies to mark 

the service bulletin number on the part, 

and suggested that having only a visual 

clue can be challenging to track. FedEx 

noted that the part number does not 

change after modification, which will 

present difficulties with operators’ part 

tracking systems. FedEx requested that 

the FAA work with Boeing to identify 

a standardized method for identifying 

modified parts, such as adding a letter 

after the serial number. 

The FAA disagrees with the 

commenters’ request. While the FAA 

acknowledges that it may be easier for 

the commenters to track modified parts 

using a revised serial number, the FAA 

cannot assume all operators would use 

the same tracking system. Additionally, 

part marking with a service bulletin 

number is an established process that 

has been required by other ADs. 

However, under the provisions specified 

in paragraph (k) of this AD, the FAA 

will consider requests for an alternative 

method of compliance (AMOC). 

Conclusion 

The FAA reviewed the relevant data, 

considered any 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 on these 

products. Except for minor editorial 

changes, and any other 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 777–27A0123 

RB, Revision 1, dated January 16, 2023. 

This service information specifies 

procedures for an inspection or records 

review for affected serial numbers of the 

TE flap transmission and gearbox 

assemblies at positions 1 through 8. For 

affected serial numbers, the service 

information specifies procedures for 

either (1) removing the TE flap 

transmission assembly and installing a 

new or serviceable assembly, or (2) 

removing the TE flap transmission and 

ratchet pawl assemblies, inspecting the 

ratchet pawl assembly for damage and 

missing material, and, depending on the 

findings, either installing a new ratchet 

pawl assembly and a changed TE flap 

transmission assembly or replacing the 

ratchet pawl assembly and TE flap 

transmission assembly with new or 

serviceable parts. 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 ADDRESSES. 

Costs of Compliance 

The FAA estimates that this AD 

affects 267 airplanes of U.S. registry. 

The FAA estimates the following costs 

to comply with this AD: 

ESTIMATED COSTS

Action Labor cost Parts cost Cost per 

product 

Cost on U.S. 

operators 

Inspection or records review ........................... 1 work-hour × $85 per hour = $85 ................. $0 $85 $22,695 

The FAA estimates the following 

costs to do any necessary replacements 

that would be required based on the 

results of the inspection or records 

review. The FAA has no way of 

determining the number of aircraft that 

might need these replacements: 

ESTIMATED COSTS FOR ON-CONDITION ACTIONS

Action Labor cost Parts cost Cost per 

product 

Replacement ................ 6 work-hours × $85 per hour = $510 .......................... $5,090 per part ................................................ $5,600 

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 


khammond on DSKJM1Z7X2PROD with RULES
Federal Register / Vol. 88, No. 217 / Monday, November 13, 2023 / Rules and Regulations 77497 

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: 

2023–21–09 The Boeing Company: 

Amendment 39–22581; Docket No. 

FAA–2023–0436; Project Identifier AD– 

2022–00395–T. 

(a) Effective Date 

This airworthiness directive (AD) is 

effective December 18, 2023. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to all The Boeing 

Company Model 777–200, 777–200LR, 777– 

300, 777–300ER, and 777F series airplanes, 

certificated in any category. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 27, Flight controls. 

(e) Unsafe Condition 

This AD was prompted by a report of a 

‘‘FLAPS DRIVE’’ caution message in flight 

due to the torque trip indicator of the No. 2 

trailing edge (TE) flap transmission assembly 

being in the set position, which resulted in 

an air turn-back. The FAA is issuing this AD 

to address a broken ratchet pawl assembly in 

combination with an upstream torque tube 

disconnect, which can cause failure of the 

no-back brake to hold flap surfaces in a 

commanded position, and possible debris in 

the transmission assembly, which can 

prevent the pawl from engaging the ratchet 

plate or cause other damage to the 

transmission assembly. The unsafe condition, 

if not addressed, could result in asymmetric 

loss of the lift that can prevent continued safe 

flight and landing. 

(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 777–27A0123 RB, 

Revision 1, dated January 16, 2023, do all 

applicable actions identified in, and in 

accordance with, the Accomplishment 

Instructions of Boeing Alert Requirements 

Bulletin 777–27A0123 RB, Revision 1, dated 

January 16, 2023. 

Note 1 to paragraph (g): Guidance for 

accomplishing the actions required by this 

AD can be found in Boeing Alert Service 

Bulletin 777–27A0123, Revision 1, dated 

January 16, 2023, which is referred to in 

Boeing Alert Requirements Bulletin 777– 

27A0123 RB, Revision 1, dated January 16, 

2023. 

(h) Exception to Service Information 

Specifications 

Where the Compliance Time columns of 

the tables in the ‘‘Compliance’’ paragraph of 

Boeing Alert Requirements Bulletin 777– 

27A0123 RB, Revision 1, dated January 16, 

2023, use the phrase ‘‘the original issue date 

of Requirements Bulletin 777–27A0123 RB,’’ 

this AD requires using ‘‘the effective date of 

this AD.’’ 

(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 777–27A0123 RB, 

dated October 11, 2021. 

(j) Parts Installation Limitation 

As of the effective date of this AD, no 

person may install, on any airplane, an 

affected TE flap transmission or gearbox 

assembly, as identified in Appendix J of 

Boeing Alert Requirements Bulletin 777– 

27A0123 RB, Revision 1, dated January 16, 

2023, unless the assembly has been inspected 

and all applicable corrective actions have 

been performed in accordance with Boeing 

Alert Requirements Bulletin 777–27A0123 

RB, Revision 1, dated January 16, 2023. 

Affected TE flap transmission or gearbox 

assemblies on which, prior to the effective 

date of this AD, the inspection and all 

applicable corrective actions have been 

performed as specified in Boeing Alert 

Requirements Bulletin 777–27A0123 RB, 

dated October 11, 2021, are acceptable for 

installation. 

(k) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, AIR–520, Continued 

Operational Safety 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 paragraph (l) of this AD. 

Information may be emailed to: 9-ANMSeattle-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 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, AIR–520, Continued Operational 

Safety 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. 

(l) Related Information 

For more information about this AD, 

contact Anthony Caldejon, Aviation Safety 

Engineer, FAA, 2200 South 216th St., Des 

Moines, WA 98198; telephone: 206–231– 

3534; email: anthony.v.caldejon@faa.gov. 

(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 the AD specifies otherwise. 

(i) Boeing Alert Requirements Bulletin 

777–27A0123 RB, Revision 1, dated January 

16, 2023. 

(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; website 

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, 

fr.inspection@nara.gov, or go to: 

www.archives.gov/federal-register/cfr/ibrlocations.html. 

Issued on October 19, 2023. 

Caitlin Locke, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2023–25046 Filed 11–9–23; 8:45 am] 

BILLING CODE 4910–13–P 


khammond on DSKJM1Z7X2PROD with RULES