FAA发布波音737NG水平安定面自由间隙最终适航令：仅检查维修、全行业成本约101万美元，无停飞且为1月提案的程序性落地

[4910-13-P]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-5403; Project Identifier AD-2025-01167-T; Amendment 3923487; AD 2026-20-14]
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 reports from multiple operators of pitch oscillation events due
to excessive horizontal stabilizer freeplay. This AD requires measuring the freeplay of
the horizontal stabilizer pivot hinges and the jackscrew and applicable on-condition
actions. The FAA is issuing this AD to address the unsafe condition on these products.
DATES: This AD is effective [INSERT DATE 35 DAYS AFTER DATE OF
PUBLICATION IN THE FEDERAL REGISTER].
The Director of the Federal Register approved the incorporation by reference of a
certain publication listed in this AD as of [INSERT DATE 35 DAYS AFTER DATE OF
PUBLICATION IN THE FEDERAL REGISTER].
ADDRESSES:
AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA2025-5403; 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 Boeing material 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.
• You may view this material 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-2025-5403.
FOR FURTHER INFORMATION CONTACT: Raymond Vital, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3521;
email: Raymond.J.Vital@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 certain The Boeing Company Model
737-600, -700, -700C, -800, -900, and -900ER series airplanes. The NPRM was
published in the Federal Register on January 9, 2026 (91 FR 931); corrected January 16,
2026 (91 FR 2090). The NPRM was prompted by reports from multiple operators of
pitch oscillation events due to excessive horizontal stabilizer freeplay. In the NPRM, the
FAA proposed to require measuring the freeplay of the horizontal stabilizer pivot hinges
and the jackscrew and applicable on-condition actions. The FAA is issuing this AD to
address excessive horizontal stabilizer freeplay. The unsafe condition, if not addressed,
could lead to a flutter event, which can result in loss of control of the airplane.

Discussion of Final Airworthiness Directive
Comments
The FAA received comments from five commenters, including the Air Line Pilots
Association, International, Boeing, and two individuals who supported the NPRM
without change.
The FAA received additional comments from four commenters, including Alaska
Airlines, Aviation Partners Boeing (APB), Canadian North, and United Airlines. The
following presents the comments received on the NPRM and the FAA’s response to each
comment.
Effect of Winglets on Accomplishment of the Proposed Actions
APB stated that the blended or split scimitar winglets installed per Supplemental
Type Certificate (STC) ST00830SE does not affect compliance with the proposed
requirements. APB further stated that, for airplanes with the split scimitar winglet (SSW)
configuration, an alternative method of compliance (AMOC) might not be able to be
obtained from The Boeing Company Organization Designation Authorization (ODA) per
paragraph (i)(2) of the proposed AD for either (1) a repair of any worn parts identified as
SSW-affected, as a result of proposed inspections, or (2) a deviation from the instructions
of the Boeing service information in an SSW-affected area. APB noted that Boeing does
not have delegated authority to approve repairs or deviations in areas affected by the
SSW configuration, but that operators of airplanes accomplishing a repair of SSWaffected parts or deviation from Boeing service information in an SSW-affected area may
obtain an alternative method of compliance (AMOC) according to paragraph (i)(1) of the
proposed AD.
The FAA agrees that the installation of STC ST00830SE does not affect the
ability to accomplish the actions required by this AD. The FAA has not changed this AD
in this regard.

Request to Extend Certain Compliance Times
Canadian North requested that the FAA extend the initial inspection threshold
from 12 months to 36 months after the original issue date of Boeing Alert Requirements
Bulletin 737-55A1104 RB, dated June 12, 2025 (Boeing Alert Requirements Bulletin
737-55A1104 RB), to align it with the repetitive inspection interval. The commenter
stated this would also align the initial inspection with the typical heavy maintenance visit,
which would allow sufficient time for procurement, planning, and logistical coordination,
thereby minimizing the risk of unscheduled downtime and reducing administrative
burden.
United Airlines noted the repetitive inspection intervals are the same regardless of
the inspection findings and applicable follow-on action, i.e., either keeping the original
parts installed or replacing or repairing a worn part. The commenter stated it believes the
repetitive inspection intervals for airplanes with newly replaced parts (specifically hinge
bearings) should be longer than the intervals for airplanes that have original production
parts installed.
The FAA disagrees with extending the initial inspection threshold and the
repetitive inspection intervals for airplanes with newly replaced parts. The FAA has
determined that the compliance times identified in the required service information will
ensure an acceptable level of safety for the fleet. Further, the repetitive inspection
intervals were chosen to ensure that excessive freeplay does not exist for either original
or new or replaced parts. However, under the provisions of paragraph (i) of this AD, the
FAA will consider requests for approval of an extension of a compliance time, if
sufficient data are submitted to substantiate that the new compliance time would provide
an acceptable level of safety. The FAA has not changed this AD in this regard.

Request to Allow a Deviation to Certain Required Actions
Alaska Airlines requested that the FAA revise paragraph (g) of the proposed AD
to allow accomplishment of Actions 1, 2, and 3 of Table 3, Condition 3 of Boeing Alert
Requirements Bulletin 737-55A1104 RB as an option to the required actions in Table 3,
Condition 2. The commenter stated that Table 3, Condition 2 drives operators to Table 4,
Condition 2, which consists of doing an interim freeplay check within 3,100 flight hours
or within 6 months after the last freeplay check, and that a second interim freeplay check
is required if the measurements of the first interim freeplay check fall under Table 4,
Condition 2.1. The commenter stated that this change would allow operators to repair or
replace parts to bring the airplane within the Level 1 limits and avoid interim freeplay
checks.
The FAA disagrees with providing a deviation to the tables in the “Compliance”
paragraph and Accomplishment Instructions of Boeing Alert Requirements Bulletin 73755A1104 RB. Table 3, Condition 2 and Table 4, Condition 2 do not prohibit
accomplishing an inspection earlier than the specified compliance time; therefore,
operators may accomplish the interim inspection in Table 4, Condition 2 early, and then
perform the repair or replacement as soon as practical within the same maintenance
period. A post-repair/replacement inspection is still required to verify freeplay values D1,
D2, D3, and H are within the Level 1 limits before the airplane is returned to service.
Additionally, under the provisions of paragraph (i) of this AD, the FAA will consider
AMOC requests for a deviation to the required actions, provided adequate supporting
information is submitted. The FAA has not changed this AD in this regard.
Request to Provide Credit for Other Service Information
United Airlines requested that the FAA revise the proposed AD to provide credit
for inspecting the horizontal stabilizer for free play using Boeing Multi-Operator
Message (MOM) MOM-MOM-22-0187-01B(R1), dated May 27, 2022 (Boeing MOM-

MOM-22-0187-01B(R1)). The commenter noted that Boeing MOM-MOM-22-018701B(R1) states operators are able to obtain credit for performing this inspection once the
eventual service bulletin and the potential AD are released. The commenter also stated it
reviewed Boeing MOM-MOM-22-0187-01B(R1) and Boeing Alert Requirements
Bulletin 737-55A1104 RB and confirmed they contain identical work instructions for the
freeplay inspection.
The FAA disagrees because it is not necessary to provide credit in this AD.
Airplanes on which accepted freeplay measurement procedures were accomplished using
Boeing MOM-MOM-22-0187-01B(R1), or other certain service information, are
classified as Group 1, Configuration 1 airplanes. Refer to the note under paragraph 1.A.,
“Effectivity,” of Boeing Alert Requirements Bulletin 737-55A1104 RB. The work
instructions for Group 1, Configuration 1 airplanes already provide some relief for prior
accomplishment of the freeplay measurement. The FAA has not changed this AD in this
regard.
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, this AD is adopted as proposed in the NPRM. None of the changes will
increase the economic burden on any operator.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Boeing Alert Requirements Bulletin 737-55A1104 RB, dated
June 12, 2025. This material specifies procedures for measuring freeplay of the left and
right horizontal stabilizer pivot hinges and the jackscrew to determine freeplay value, and
applicable on-condition actions. On-condition actions include determining total
horizontal stabilizer freeplay, repeating the freeplay measurement procedure of the

horizontal stabilizer pivot hinges and the jackscrew, and replacement or repair of any
worn parts.
This material 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 1,987 airplanes of U.S. registry. The FAA
estimates the following costs to comply with this AD:
Estimated costs
Action

Labor cost

Parts cost

Freeplay measurement
procedure

6 work-hours X $85
$0
per hour = $510

Cost per
product

Cost on U.S.
operators

$510

$1,013,370

The FAA estimates the following costs to do any necessary replacements that
would be required based on the results of the inspection. The agency has no way of
determining the number of aircraft that might need these replacements:
On-condition costs
Action

Labor cost

Parts cost

Cost per product

Repeat freeplay
measurement procedure

6 work-hours X $85
per hour = $510

$0

$510

Replacement or repair of
worn parts

1 work-hour X $85 per
hour = $85

$0*

$85

* The FAA has received no definitive data on which to base the cost estimate for the
worn parts.
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.
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:
2026-20-14 The Boeing Company: Amendment 39-23487; Docket No. FAA-20255403; Project Identifier AD-2025-01167-T.
(a) Effective Date
This airworthiness directive (AD) is effective [INSERT DATE 35 DAYS AFTER
DATE OF PUBLICATION IN THE FEDERAL REGISTER].
(b) Affected ADs
None.
(c) Applicability
This AD applies to The Boeing Company Model 737-600, -700, -700C, -800,
-900, and -900ER series airplanes, certificated in any category, as identified in Boeing
Alert Requirements Bulletin 737-55A1104 RB, dated June 12, 2025.
(d) Subject
Air Transport Association (ATA) of America Code 55, Stabilizers.
(e) Unsafe Condition
This AD was prompted by reports from multiple operators of pitch oscillation
events due to excessive horizontal stabilizer freeplay. The FAA is issuing this AD to
address excessive horizontal stabilizer freeplay. The unsafe condition, if not addressed,
could lead to a flutter event, which can result in loss of control 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 737-55A1104 RB,
dated June 12, 2025, do all applicable actions identified in, and in accordance with, the

Accomplishment Instructions of Boeing Alert Requirements Bulletin 737-55A1104 RB,
dated June 12, 2025.
Note 1 to paragraph (g): Guidance for accomplishing the actions required by
this AD can be found in Boeing Alert Service Bulletin 737-55A1104, dated June 12,
2025, which is referred to in Boeing Alert Requirements Bulletin 737-55A1104 RB,
dated June 12,2025.
(h) Exception to Requirements Bulletin Specifications
Where the “Effectivity” paragraph and the Boeing Recommended Compliance
Time columns of the tables in the “Compliance” paragraph of Boeing Alert Requirements
Bulletin 737-55A1104 RB, dated June 12, 2025, refer to the original issue date of the
Requirements Bulletin 737-55A1104 RB, this AD requires using the effective date of this
AD.
(i) 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 Continued Operational Safety Branch, send it to the
attention of the person identified in paragraph (j) of this AD. Information may be emailed
to: AMOC@faa.gov. Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager of the responsible Flight
Standards Office.
(2) 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.
(j) Additional Information
(1) For more information about this AD, contact Raymond Vital, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3521;
email: Raymond.J.Vital@faa.gov.
(2) Material identified in this AD that is not incorporated by reference is available
at the address specified in paragraph (k)(3) of this AD.
(k) Material Incorporated by Reference
(1) The Director of the Federal Register approved the incorporation by reference
of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this material as applicable to do the actions required by this AD,
unless the AD specifies otherwise.
(i) Boeing Alert Requirements Bulletin 737-55A1104 RB, dated June 12, 2025.
(ii) [Reserved]
(3) For Boeing material 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 material 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 material at the National Archives and Records
Administration (NARA). For information on the availability of this material at NARA,

visit www.archives.gov/federal-register/cfr/ibr-locations or email
fr.inspection@nara.gov.
Issued on October 9, 2026.

Brian Knaup,
Acting Deputy Director, Integrated Certificate Management Division,
Aircraft Certification Service.
[FR Doc. 2026-21333 Filed: 10/16/2026 8:45 am; Publication Date: 10/19/2026]