
[Federal Register Volume 88, Number 217 (Monday, November 13, 2023)]
[Rules and Regulations]
[Pages 77495-77497]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-25046]



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 Rules and Regulations
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  Federal Register / Vol. 88, No. 217 / Monday, November 13, 2023 / 
Rules and Regulations  

[[Page 77495]]



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: [email protected].

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 on-condition 
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

[[Page 77496]]

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
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Inspection or records review..........  1 work-hour x $85 per                 $0             $85         $22,695
                                         hour = $85.
----------------------------------------------------------------------------------------------------------------

    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
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                 Action                           Labor cost                  Parts cost              product
----------------------------------------------------------------------------------------------------------------
Replacement.............................  6 work-hours x $85 per      $5,090 per part...........          $5,600
                                           hour = $510.
----------------------------------------------------------------------------------------------------------------

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

[[Page 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

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13   [Amended]

0
2. The FAA amends Sec.  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: [email protected].
    (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: [email protected].

(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, [email protected], or go to: www.archives.gov/federal-register/cfr/ibr-locations.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


