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Published 2018-12-06 · Federal Register document 2018-26365

Airworthiness Directives; The Boeing Company Airplanes

Publication summary

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-8 and -9 airplanes. This emergency AD was sent previously to all known U.S. owners and operators of these airplanes. This AD requires revising certificate limitations and operating procedures of the airplane flight manual (AFM) to provide the flight crew with runaway horizontal stabilizer trim procedures to follow under certain conditions. This AD was prompted by analysis performed by the manufacturer showing that if an erroneously high single angle of attack (AOA) sensor input is received by the flight control system, there is a potential for repeated nose-down trim commands of the horizontal stabilizer. We are issuing this AD to address the unsafe condition on these products.

Why this record is shown

Source: Federal Register annual FAA metadata. Acquired 2026-09-03T22:23:58.123663+00:00. The title, summary and date are source facts.

Source revision
federal_register_ad_metadata_2018-258c65fa72d503e0
Source row
results[373]
Raw source SHA-256
258c65fa72d503e0b0dfb928a28beb1793ddc7dd9218bce0413e53dfe11d78fb

Final-rule publication

Recorded publication clauses

AD identifier printed in this edition
2018-23-51
Effective date printed in this edition
Unknown
Read 11 complete recorded clauses
Effective Date
(a) Effective Date

    This AD is effective December 21, 2018 to all persons except 
those persons to whom it was made immediately effective by Emergency 
AD 2018-23-51, issued on November 7, 2018, which contained the 
requirements of this amendment.

Exact source excerpt. Text positions 10566–10819, end exclusive, in the original decoded publication. SHA-256: eb046b28442ba11d91f74db4aa64d48e758ad2a46b3a61a7d18a2904a70c7f8c

Affected ADs
(b) Affected ADs

    None.

Exact source excerpt. Text positions 10819–10848, end exclusive, in the original decoded publication. SHA-256: 871a4afc60ceeae06e8010585055188633d616078500c45937092bfe892239c0

Applicability wording · Applicability
(c) Applicability

    This AD applies to all The Boeing Company Model 737-8 and -9 
airplanes, certificated in any category.

Exact source excerpt. Text positions 10848–10975, end exclusive, in the original decoded publication. SHA-256: feaf23b3dc276aecc2ef66e5e397e2a8e090394998747e4cba950f49f60371ba

Subject
(d) Subject

    Air Transport Association (ATA) of America Code 27, Flight 
controls.

Exact source excerpt. Text positions 10975–11063, end exclusive, in the original decoded publication. SHA-256: 5df668a44f125df3e991e4d0d4055a7abf4e497975e862633d97c2c7cacf4016

Unsafe Condition
(e) Unsafe Condition

    This AD was prompted by analysis performed by the manufacturer 
showing that if an erroneously high single angle of attack (AOA) 
sensor input is received by the flight control system, there is a 
potential for repeated nose-down trim commands of the horizontal 
stabilizer. We are issuing this AD to address this potential 
resulting nose-down trim, which could cause the flight crew to have 
difficulty controlling the airplane, and lead to excessive nose-down 
attitude, significant altitude loss, and possible impact with 
terrain.

Exact source excerpt. Text positions 11063–11626, end exclusive, in the original decoded publication. SHA-256: fe4eb435563673c86156060a2724c1365546ea2dccc3ceab6ffa648dfb44e394

Compliance
(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

Exact source excerpt. Text positions 11626–11728, end exclusive, in the original decoded publication. SHA-256: 00fbfa31932483f627d0ce0a11cbd2e35e15d9231842b91ac85623ce533912d3

Revision of Airplane Flight Manual (AFM): Certificate Limitations
(g) Revision of Airplane Flight Manual (AFM): Certificate Limitations

    Within 3 days after the effective date of this AD, revise the 
Certificate Limitations chapter of the applicable AFM to include the 
information in figure 1 to paragraph (g) of this AD.

[[Page 62699]]

[GRAPHIC] [TIFF OMITTED] TR06DE18.000

Exact source excerpt. Text positions 11728–12045, end exclusive, in the original decoded publication. SHA-256: 92d077607776ec864c72a1bb686a98bab3863a56a30d2cbc3161f7478816c788

AFM Revision: Operating Procedures
(h) AFM Revision: Operating Procedures

    Within 3 days after the effective date of this AD, revise the 
Operating Procedures chapter of the applicable AFM to include the 
information in figure 2 to paragraph (h) of this AD.

[[Page 62700]]

[GRAPHIC] [TIFF OMITTED] TR06DE18.001

Exact source excerpt. Text positions 12045–12328, end exclusive, in the original decoded publication. SHA-256: 18157bd8b721a1b52ee64a468d080ad74cfc7f476194d0399bc21687d390b24c

Alternative Methods of Compliance (AMOCs)
 (i) 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 (j) 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 local flight standards district office/certificate holding 
district office.

Exact source excerpt. Text positions 12328–13095, end exclusive, in the original decoded publication. SHA-256: 3eae382f74f2b2439f7224f47deadfd343b73b93065191016aea372e8c094028

Related Information
(j) 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 and fax: 206-231-3548; email: [email protected].

Exact source excerpt. Text positions 13095–13369, end exclusive, in the original decoded publication. SHA-256: 302ddab89cd1a028b5025f248081c6655730fcd77f04158cec3ab84ce5721bed

Material Incorporated by Reference
(k) Material Incorporated by Reference

    None.

Exact source excerpt. Text positions 13369–13420, end exclusive, in the original decoded publication. SHA-256: 3cd458e4139c18aa2b217c588b225868252e2c1201e03a6c776e06e2cf7b2987

No replacement link has been established from this edition. The complete historical rule chain and current legal effect remain unknown.

Find all recorded historical references to AD 2018-23-51 · 1 printed reference observations in this pinned collection.

These are observations from one dated publication. Current legal status is unknown; aircraft applicability, installed configuration, compliance and burden require separate evidence. Missing or unparsed conditions remain unknown.

Why these observations are shown

They were extracted offline from the same immutable official HTML source as the complete recorded text. The dated source wording, original text coordinates and exact quote digests are retained. PDF/text agreement and current regulatory effect have not been qualified.

Observation revision: whole-ad-publication-clause-observations-1.0.1. Text SHA-256: 524411f1ca4c0da0b526bfdf439f5f39c3a6f38c32e71c4b36637b158db36048. Source manifest: 4c16ba6073c6b75ba5c0c10384b605a54ca1d9ac4eaea17f5f48cc611a100eda.

Official source · 2018-12-06

Publication text

This is the complete recorded text of this dated publication.

Current legal effect is unknown. Aircraft applicability, installed configuration and compliance require separate evidence. PDF/text agreement has not been evaluated.

Read the complete official publication text
[Federal Register Volume 83, Number 234 (Thursday, December 6, 2018)]
[Rules and Regulations]
[Pages 62697-62700]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-26365]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0960; Product Identifier 2018-NM-151-AD; Amendment 
39-19512; AD 2018-23-51]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

-----------------------------------------------------------------------

SUMMARY: We are adopting a new airworthiness directive (AD) for all The 
Boeing Company Model 737-8 and -9 airplanes. This emergency AD was sent 
previously to all known U.S. owners and operators of these airplanes. 
This AD requires revising certificate limitations and operating 
procedures of the airplane flight manual (AFM) to provide the flight 
crew with runaway horizontal stabilizer trim procedures to follow under 
certain conditions. This AD was prompted by analysis performed by the 
manufacturer showing that if an erroneously high single angle of attack 
(AOA) sensor input is received by the flight control system, there is a 
potential for repeated nose-down trim commands of the horizontal 
stabilizer. We are issuing this AD to address the unsafe condition on 
these products.

DATES: This AD is effective December 21, 2018 to all persons except 
those persons to whom it was made immediately effective by Emergency AD 
2018-23-51, issued on November 7, 2018, which contained the 
requirements of this amendment.
    We must receive comments on this AD by January 22, 2019.

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 http://www.regulations.gov. 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.

Examining the AD Docket

    You may examine the AD docket on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2018-
0960; 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, the regulatory evaluation, any comments received, and 
other information. The street address for Docket Operations (phone: 
800-647-5527) is in the ADDRESSES section. Comments will be available 
in the AD docket shortly after receipt.

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 and fax: 206-231-3548; 
email: [email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    On November 7, 2018, we issued Emergency AD 2018-23-51, which 
requires revising certificate limitations and operating procedures of 
the AFM to provide the flight crew with runaway horizontal stabilizer 
trim procedures to follow under certain conditions. This emergency AD 
was sent previously to all known U.S. owners and operators of these 
airplanes. This action was prompted by analysis performed by the 
manufacturer showing that if an erroneously high single AOA sensor 
input is received by the flight control system, there is a potential 
for repeated nose-down trim commands of the horizontal stabilizer. This 
condition, if not addressed, could cause the flight crew to have 
difficulty controlling the airplane, and lead to excessive nose-down 
attitude, significant altitude loss, and possible impact with terrain.

FAA's Determination

    We are issuing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design.

AD Requirements

    This AD requires revising certificate limitations and operating 
procedures of the AFM to provide the flight crew with runaway 
horizontal stabilizer trim procedures to follow under certain 
conditions.

Interim Action

    We consider this AD interim action. If final action is later 
identified, we might consider further rulemaking then.

FAA's Determination of the Effective Date

    An unsafe condition exists that requires the immediate adoption of 
Emergency AD 2018-23-51, issued on November 7, 2018, to all known U.S. 
owners and operators of these airplanes. The FAA found that the risk to 
the flying public justified waiving notice and comment prior to 
adoption of this rule because an erroneously high single AOA sensor 
input received by the flight control system can result in a potential 
for repeated nose-down trim commands of the horizontal stabilizer, 
which could cause the flight crew to have difficulty controlling the 
airplane, and lead to excessive nose-down attitude, significant 
altitude loss, and possible impact with terrain. These conditions still 
exist and the AD is hereby published in the Federal Register as an 
amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 
39.13) to make it effective to all persons. Therefore, we find good 
cause that notice and opportunity for prior public comment are 
impracticable. In addition, for the reason(s) stated above, we find 
that good cause exists for making this amendment effective in less than 
30 days.

Comments Invited

    This AD is a final rule that involves requirements affecting flight 
safety and was not preceded by notice and an opportunity for public 
comment. However, we invite you to send any written data, views, or 
arguments about

[[Page 62698]]

this final rule. Send your comments to an address listed under the 
ADDRESSES section. Include the docket number FAA-2018-0960 and Product 
Identifier 2018-NM-151-AD at the beginning of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of this final rule. We will consider 
all comments received by the closing date and may amend this final rule 
because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this final rule.

Costs of Compliance

    We estimate that this AD affects 45 airplanes of U.S. registry. We 
estimate the following costs to comply with this AD:

                                      Estimated Costs for Required Actions
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Revising the AFM......................  1 work-hour x $85 per                 $0             $85          $3,825
                                         hour = $85.
----------------------------------------------------------------------------------------------------------------

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.
    We are 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.
    This AD is issued in accordance with authority delegated by the 
Executive Director, Aircraft Certification Service, as authorized by 
FAA Order 8000.51C. In accordance with that order, issuance of ADs is 
normally a function of the Compliance and Airworthiness Division, but 
during this transition period, the Executive Director has delegated the 
authority to issue ADs applicable to transport category airplanes and 
associated appliances to the Director of the System Oversight Division.

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) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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

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 (AD):

2018-23-51 The Boeing Company: Amendment 39-19512; Docket No. FAA-
2018-0960; Product Identifier 2018-NM-151-AD.

(a) Effective Date

    This AD is effective December 21, 2018 to all persons except 
those persons to whom it was made immediately effective by Emergency 
AD 2018-23-51, issued on November 7, 2018, which contained the 
requirements of this amendment.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737-8 and -9 
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 analysis performed by the manufacturer 
showing that if an erroneously high single angle of attack (AOA) 
sensor input is received by the flight control system, there is a 
potential for repeated nose-down trim commands of the horizontal 
stabilizer. We are issuing this AD to address this potential 
resulting nose-down trim, which could cause the flight crew to have 
difficulty controlling the airplane, and lead to excessive nose-down 
attitude, significant altitude loss, and possible impact with 
terrain.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Revision of Airplane Flight Manual (AFM): Certificate Limitations

    Within 3 days after the effective date of this AD, revise the 
Certificate Limitations chapter of the applicable AFM to include the 
information in figure 1 to paragraph (g) of this AD.

[[Page 62699]]

[GRAPHIC] [TIFF OMITTED] TR06DE18.000

(h) AFM Revision: Operating Procedures

    Within 3 days after the effective date of this AD, revise the 
Operating Procedures chapter of the applicable AFM to include the 
information in figure 2 to paragraph (h) of this AD.

[[Page 62700]]

[GRAPHIC] [TIFF OMITTED] TR06DE18.001

 (i) 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 (j) 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 local flight standards district office/certificate holding 
district office.

(j) 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 and fax: 206-231-3548; email: [email protected].

(k) Material Incorporated by Reference

    None.

    Issued in Des Moines, Washington, on November 21, 2018.
Michael Kaszycki,
Acting Director, System Oversight Division, Aircraft Certification 
Service.
[FR Doc. 2018-26365 Filed 12-4-18; 8:45 am]
 BILLING CODE 4910-13-P


Why this text is shown

The complete text was extracted from the official GovInfo HTML edition for this publication. Acquired 2026-10-09T02:10:16.962389+00:00. Text extraction preserves the recorded source wording; it does not determine current requirements.

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Source SHA-256
db96f1e335948622efe0595cbe770cb5517fcc2818c4678b9151c2e3bb082d01
Text SHA-256
524411f1ca4c0da0b526bfdf439f5f39c3a6f38c32e71c4b36637b158db36048

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Coverage and limits

These are dated publication metadata, recorded clauses and literal source observations. Word, model-label, header and reference matches do not establish current legal effect, manufacturer/model identity, aircraft applicability, installed configuration or compliance.

The collection uses 33 explicit annual source snapshots. Source captures and operative-text qualifications have separate states. Missing information remains unknown.