Proposed Rule2023-07011
Airworthiness Directives; The Boeing Company Airplanes
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
April 6, 2023
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to adopt a new airworthiness directive (AD) for all The Boeing Company Model 777-200, 777-200LR, 777-300, 777- 300ER, and 777F series airplanes. This proposed 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 proposed AD would 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. This proposed AD would also limit the installation of affected parts. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 88 Issue 66 (Thursday, April 6, 2023)</title>
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[Federal Register Volume 88, Number 66 (Thursday, April 6, 2023)]
[Proposed Rules]
[Pages 20433-20436]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-07011]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2023-0436; Project Identifier AD-2022-00395-T]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for all The Boeing Company Model 777-200, 777-200LR, 777-300, 777-
300ER, and 777F series airplanes. This proposed 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 proposed AD would 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. This
proposed AD would also limit the installation of affected parts. 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 May 22,
2023.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="http://regulations.gov">regulations.gov</a>. Follow
the instructions for submitting comments.
<bullet> Fax: 202-493-2251.
<bullet> 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.
<bullet> Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a> 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 NPRM, any comments received, and other
information. The street address for Docket Operations is listed above.
Material Incorporated by Reference:
<bullet> For service information identified in this NPRM, 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 <a href="http://myboeingfleet.com">myboeingfleet.com</a>.
<bullet> 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
<a href="http://regulations.gov">regulations.gov</a> by searching for and locating Docket No. FAA-2023-0436.
[[Page 20434]]
FOR FURTHER INFORMATION CONTACT: Douglas Tsuji, Senior Aerospace
Engineer, Systems and Equipment Section, FAA, Seattle ACO Branch, 2200
South 216th St., Des Moines, WA 98198; phone: 206-231-3548; email:
<a href="/cdn-cgi/l/email-protection#fb9f948e9c979a88d58f888e9192bb9d9a9ad59c948d"><span class="__cf_email__" data-cfemail="23474c56444f42500d575056494a634542420d444c55">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
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-2023-0436; Project Identifier
AD-2022-00395-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
this 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
<a href="http://regulations.gov">regulations.gov</a>, 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
Douglas Tsuji, Senior Aerospace Engineer, Systems and Equipment
Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA
98198; phone: 206-231-3548; email: <a href="/cdn-cgi/l/email-protection#593d362c3e35382a772d2a2c3330193f3838773e362f"><span class="__cf_email__" data-cfemail="9cf8f3e9fbf0fdefb2e8efe9f6f5dcfafdfdb2fbf3ea">[email protected]</span></a>. Any
commentary that the FAA receives that is not specifically designated as
CBI will be placed in the public docket for this rulemaking.
Background
The FAA has received a report of a ``FLAPS DRIVE'' caution message
in flight, which resulted in an air turn-back. Subsequent investigation
found that the torque trip indicator of the No. 2 trailing edge (TE)
flap transmission assembly was in the set position, which had caused
the ``FLAPS DRIVE'' caution message. The TE flap transmission assembly
was removed from the airplane and sent for a teardown inspection to
find the cause of the problem. The teardown inspection revealed a
broken no-back brake ratchet pawl; the broken piece had lodged itself
between the housing and a drive gear, which had resulted in a TE flap
transmission assembly lock-up condition. A subsequent Boeing analysis
of the broken pawl found that the spring guide pin bore did not meet
design requirements. The depth of the pawl bore was more than the
specified requirement, and its inner diameter was insufficient.
Further, the drawing requirement for the pawl bore inner diameter
resulted in an undersized spring guide pin bore, which caused an
excessive interference fit between the bore and spring guide, which in
turn caused the ratchet pawl assembly to break.
From in-service reports, there have been three known incidents of
Model 777 TE flap transmission no-back brake ratchet pawls cracking in
service from the same supplier since 2018. The same ratchet pawl part
number is used on all eight TE flap transmissions. Historically, these
pawls have been fabricated by three different sub-tier suppliers. The
three broken pawls were manufactured by the same sub-tier supplier,
which is no longer in business. The root cause of the unsafe condition
has been determined to be the undersized bores in the suspect pawls
causing an interference fit with the mating spring guide pin resulting
in increased hoop stresses in the pawl. A review of two inspection
reports revealed that the sub-tier supplier had misread the bore
requirements.
A broken ratchet pawl assembly, in combination with an upstream
torque tube disconnect, can cause failure of the no-back brake to hold
flap surfaces in a commanded position--a condition referred to as flap
``blowback.'' In addition, a broken ratchet pawl assembly can allow
debris in the transmission assembly, which can prevent the pawl from
engaging the ratchet plate or cause other damage to the transmission
assembly. Both conditions can cause failure of the no-back brake, in
combination with an upstream torque tube disconnect, which could lead
to uncommanded retraction of the TE flap resulting in asymmetric loss
of lift that can affect continued safe flight and landing.
FAA's Determination
The FAA is issuing this NPRM after determining that the unsafe
condition described previously is likely to exist or develop on other
products of the same type design.
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.
Proposed AD Requirements in This NPRM
This proposed AD would require accomplishing the actions specified
in the service information already described. For information on the
procedures and compliance times, see this service information at
<a href="http://regulations.gov">regulations.gov</a> by searching for and locating Docket No. FAA-2023-0436.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 267 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:
[[Page 20435]]
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Inspection or records review........ 1 work-hour x $85 per $0 $85 $22,695
hour = $85.
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The FAA estimates the following costs to do any necessary
replacement(s) 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
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Cost per
Action Labor cost Parts cost product
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Replacement............................ 6 work-hours x $85 per $5,090 per part........... $5,600
hour = $510.
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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
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
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:
The Boeing Company: Docket No. FAA-2023-0436; Project Identifier AD-
2022-00395-T.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by May 22, 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.
[[Page 20436]]
(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.
(k) 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 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: <a href="/cdn-cgi/l/email-protection#794054383734542a1c180d0d151c54383a36543834363a542b1c080c1c0a0d0a391f1818571e160f"><span class="__cf_email__" data-cfemail="330a1e727d7e1e60565247475f561e72707c1e727e7c701e6156424656404740735552521d545c45">[email protected]</span></a>.
(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, Seattle
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.
(l) Related Information
For more information about this AD, contact Douglas Tsuji,
Senior Aerospace Engineer, Systems and Equipment Section, FAA,
Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198;
phone: 206-231-3548; email: <a href="/cdn-cgi/l/email-protection#7d1912081a111c0e53090e0817143d1b1c1c531a120b"><span class="__cf_email__" data-cfemail="bfdbd0cad8d3decc91cbcccad5d6ffd9dede91d8d0c9">[email protected]</span></a>.
(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 <a href="http://myboeingfleet.com">myboeingfleet.com</a>.
(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, <a href="/cdn-cgi/l/email-protection#bfd9cd91d6d1cccfdadccbd6d0d1ffd1decdde91d8d0c9"><span class="__cf_email__" data-cfemail="2046520e494e5350454354494f4e604e4152410e474f56">[email protected]</span></a>, or go to: <a href="http://www.archives.gov/federal-register/cfr/ibr-locations.html">www.archives.gov/federal-register/cfr/ibr-locations.html</a>.
Issued on March 9, 2023.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2023-07011 Filed 4-5-23; 8:45 am]
BILLING CODE 4910-13-P
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