[Federal Register Volume 86, Number 144 (Friday, July 30, 2021)]
[Rules and Regulations]
[Pages 40927-40932]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-16174]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0333; Product Identifier 2020-NM-015-AD; Amendment 
39-21623; AD 2021-13-18]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
The Boeing Company Model 737 airplanes powered by LEAP-1B engines. This 
AD was prompted by reports of inadvertent release of the spring energy 
of the spring door opening system (SDOS) actuator with a certain part 
number, causing injury and the potential for injury to maintenance 
personnel. This AD requires replacing each affected SDOS actuator with 
a new SDOS actuator, and verifying that new safety markers are 
installed in the proper locations. The FAA is issuing this AD to 
address the unsafe condition on these products.

DATES: This AD is effective September 3, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of September 3, 
2021.

ADDRESSES: 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; internet https://www.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 on 
the internet at https://www.regulations.gov by searching for and 
locating Docket No. FAA-2020-0333.

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-
0333; 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

[[Page 40928]]

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.

FOR FURTHER INFORMATION CONTACT: Rose Len, Aerospace Engineer, 
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3604; 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 737-8 and 737-9 airplanes. The NPRM published in the Federal 
Register on April 20, 2020 (85 FR 21791).
    The NPRM was prompted by a report of an incident involving an SDOS 
actuator. The SDOS actuator is a telescopic, spring-loaded actuator 
that assists the mechanic in raising the engine fan cowl. Even when the 
actuator is extended (uncompressed), it retains energy in the spring 
(preloaded). In the incident, after an SDOS actuator with part number 
BOE-2001-901F was removed, a part separation occurred at the joint 
between the actuator's inner tube and its related ``back end'' bracket. 
The actuator came apart with spring-propelled force, injuring one of 
the maintenance personnel. This SDOS actuator used two roll pins and 
epoxy at this joint. The FAA has determined that this design, together 
with spring preload, caused these parts to break.
    The FAA received a second report of a hazardous sudden extension of 
this actuator when, during improper removal of the SDOS actuator from 
the engine fan cowl while it was retracted, the SDOS actuator rapidly 
extended, with the potential to cause injury. This was possible because 
the fastener connecting the SDOS actuator to the fan cowl can be 
removed by cracking open the fan cowl and reaching under it. After the 
fastener was removed, the SDOS actuator was still connected to the 
engine fan case and was held in the retracted position by the ``catch'' 
hook, per the design. When the SDOS was rotated upward by hand, the 
catch hook released, and the SDOS actuator rapidly extended. The FAA 
has determined that the design of the SDOS actuator with part number 
BOE-2001-901H obscures the safety marker when the fan cowl is opened. 
The design of this SDOS actuator could, during maintenance, result in 
injury to maintenance personnel or damage to the airplane.
    The manufacturer of the SDOS actuator, General Aerospace, has 
changed the design to have a stronger joint between the inner tube and 
the ``back end'' bracket that uses blind rivets rather than pins, 
together with an improved shape of the ``catching'' bracket. This 
redesign addressed the aforementioned part separation of the SDOS 
actuator, and the redesigned actuator became part number BOE-2001-901H. 
General Aerospace then modified part number BOE-2001-901H to include 
more detailed safety markers in new locations that display the warnings 
more clearly to maintenance personnel. That redesign addressed the 
aforementioned extension of the SDOS actuator from release of the catch 
hook. With the addition of the more detailed safety markers in the new 
locations, the SDOS actuator part number changed from BOE-2001-901H to 
BOE-2001-901J. General Aerospace Service Bulletin BOE-2001-901-71-01, 
dated November 2, 2019, which is referenced in Boeing Service Bulletin 
737-71-1911, Revision 1, dated September 10, 2020, provides 
instructions for changing a BOE-2001-901H SDOS actuator to a BOE-2001-
901J SDOS actuator.
    The NPRM therefore proposed to require replacing each affected SDOS 
actuator with a new SDOS actuator, and verifying that the new safety 
markers are installed in the proper locations on the SDOS actuator.
    The FAA is issuing this AD to address the possible separation of 
the SDOS actuator, and the visual obstruction of the SDOS actuator 
safety marker, either of which, during maintenance, could cause injury 
to maintenance personnel or damage to the airplane.

Actions Since the NPRM Was Issued

    In the NPRM, the FAA proposed that the AD would apply to Boeing 
model 737-8 and 737-9 airplanes. Since then, the FAA determined that 
all Boeing model 737 airplanes powered by LEAP-1B engines (737 MAX 
airplanes), have engine fan cowls on which affected SDOS actuators 
could be installed. The affected SDOS actuators are rotable parts, so 
the future replacement of an SDOS actuator could reintroduce the unsafe 
condition. The 737 airplane models that are powered by LEAP-1B engines, 
and therefore that have fan cowls on which affected SDOS actuators 
could be installed, are currently the Model 737-8, 737-9, and 737-
8200.\1\ The airplane models on which affected actuators could be 
installed could include any 737 models which will be powered by LEAP-1B 
engines, such as the Model 737-7. Therefore the FAA has revised the 
applicability of this AD to include all Model 737 airplanes powered by 
LEAP-1B engines. The prohibition on the installation of an affected 
SDOS actuator similarly applies to all airplanes identified in the 
applicability of this AD.
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    \1\ The FAA type certificated the Model 737-8200 on March 31, 
2021; there are currently no U.S. operators of that model.
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Comments

    The FAA gave the public the opportunity to participate in 
developing this final rule. The following presents the comments 
received on the NPRM and the FAA's response to each comment.

Request To Update the Service Information to the Latest Revision

    Boeing requested that the FAA mandate Boeing Special Attention 
Requirements Bulletin 737-71-1911 RB, Revision 1, dated September 10, 
2020, because of various updates including removing retrofitted 
airplanes from the effectivity, group and configuration changes, and 
adapting certain instructions to allow work to be done on an individual 
fan cowl instead of all fan cowls at once. The revised service 
information does not add work for any airplane.
    The FAA agrees. The service information mandated by this AD has 
been updated, to Boeing Special Attention Requirements Bulletin 737-71-
1911 RB, Revision 1, dated September 10, 2020.

Request To Include Later Approved Revisions of the Service Information

    American Airlines and United Airlines requested that paragraph (g) 
of the proposed AD be changed to include the words ``or later approved 
revisions'' with regards to Boeing Special Attention Requirements 
Bulletin 737-71-1911 RB, dated November 26, 2019.
    The requested revision to paragraph (g) of the proposed AD to allow 
use of later-approved revisions of the service information would be 
contrary to Office of the Federal Register (OFR) regulations regarding 
incorporation by reference. Specifically, incorporation by reference of 
a publication is limited to the edition of the publication that is 
approved by OFR. 1 CFR 51.1(f). To allow operators to use later 
revisions of the referenced document that are not approved by the OFR 
and identified in the AD, either the FAA must (1) seek OFR approval to 
incorporate a later revision of the service document and revise the AD 
to reference the approved later revision, or (2) operators must request 
approval to use a later revision as an alternative

[[Page 40929]]

method of compliance with this AD under the provisions of paragraph (k) 
of this AD.

Request for Clarification of the RC Steps in the Service Information

    American Airlines requested clarification of paragraph (g) of the 
proposed AD. The commenter stated that it believes that the RC steps in 
both Boeing Special Attention Service Bulletin 737-71-1911 and 
Requirements Bulletin 737-71-1911 RB can be interpreted to mean that 
all steps of each Work Package are Required for Compliance. The company 
also states that the instruction to ``Refer to the listed procedures in 
SB 737-71-1911 Original Issue or later approved revisions as an 
accepted procedure'' found in each Work Package can be interpreted to 
mean that any part of the Work Package can be deviated from at the 
discretion of the operator, using the accepted procedures in the 
service information.
    The FAA notes that Boeing's intention in including the multiple 
Work Packages, and the FAA's intention in mandating them, is to provide 
flexibility to the operator in the sequence of performing the mandated 
corrective actions. Each Work Package can be implemented one at a time. 
Each Work Package is defined by a unique combination of Group, 
Configuration, Engine 1 or Engine 2, and LEFT or RIGHT Fan Cowl 
descriptors. All of the Work Packages do not apply to every affected 
airplane.
    The FAA further notes that both Boeing Special Attention Service 
Bulletin 737-71-1911 and Requirements Bulletin 737-71-1911 RB are 
consistent in their ``RC: Start'' and ``RC: End'' designations, which 
clearly delineate those Required Actions that are mandated by this AD. 
The instructions outside of the ``RC: Start'' and ``RC: End'' steps can 
be used to accomplish the required actions, but the AD does not 
authorize operators to use them as alternatives to the required 
actions. Where the service information specifies to ``refer to'' a 
recommended procedure, and only for those steps, operators may use an 
accepted alternative procedure.
    The FAA has added paragraph (i) to this AD to provide credit for 
the previous accomplishment of Boeing Special Attention Requirements 
Bulletin 737-71-1911 RB, dated November 26, 2019.

Request for Clarification on the Correct Number of Safety Markers

    American Airlines asked if the FAA requires a certain number of 
safety markers on SDOS part number (P/N) BOE-2001-901J units that have 
been changed from SDOS P/N BOE-2001-901H units. The AD requires that 
two P/N 12299 safety markers be installed on the SDOS actuator outer 
tube (cowl door side) if they are not already installed, but the 
commenter noted that there could be a third safety marker, P/N BOE-
2001-713, already installed.
    The FAA notes that an operator can comply with this AD by 
installing either (1) a P/N BOE-2001-901J actuator with its two 
original safety markers, or (2) a P/N BOE-2001-901H actuator that has 
been converted to a P/N BOE-2001-901J actuator with two new safety 
markers, with or without a third marker. The FAA has not changed this 
AD regarding this request.

Request for Clarification on Newly Delivered Airplanes

    American Airlines requested clarification on whether the operator 
would need to request an AMOC for the newly delivered airplanes that 
already have the SDOS part number BOE-2001-901J. The commenter noted 
that paragraph (g) of the proposed AD did not include Boeing Special 
Attention Requirements Bulletin 737-71-1911 RB, Revision 1, dated 
September 10, 2020.
    The FAA notes that AMOCs will not be necessary for airplanes that 
are newly delivered with the P/N BOE-2001-901J SDOS actuator installed. 
As previously explained, paragraph (g) of this AD has been updated to 
include Boeing Special Attention Requirements Bulletin 737-71-1911 RB, 
Revision 1, dated September 10, 2020, which includes a revised 
effectivity list. No further change to this AD is necessary.

Request for Change to the Airplane Applicability

    American Airlines and United Airlines requested that paragraph (c) 
of the proposed AD be amended to be limited to airplanes identified in 
the Effectivity section of Boeing Special Attention Requirements 
Bulletin 737-71-1911 RB. As an alternative, American Airlines requested 
that a sub-paragraph be added to paragraph (h) of the proposed AD to 
state that a review of maintenance and delivery records can be used to 
determine the installed SDOS actuator part number, provided the SDOS 
part number can be definitively determined from the records check.
    The FAA notes that paragraph (c) of this AD now includes all Boeing 
Model 737 airplanes powered by LEAP-1B engines. Paragraph (g) of this 
AD now mandates Boeing Special Attention Requirements Bulletin 737-71-
1911 RB, Revision 1, dated September 10, 2020. Because all Model 737 
airplanes powered by LEAP-1B engines have engine fan cowls that, due to 
the rotability of the affected parts, are subject to the same SDOS 
actuator issue, paragraph (j) of this AD now prohibits the installation 
of SDOS actuators having part numbers BOE-2001-901F and BOE-2001-901H 
on all Model 737 airplanes powered by LEAP-1B engines.

Request To Allow Use of Alternative Lockwire

    American Airlines requested that the FAA allow use of .040 lockwire 
for the lock wire specified in steps 1(b) and 2(b) of the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 737-71-1911, dated November 26, 2019. American Airlines noted 
that the .040 lockwire is more common and readily available than .041 
lockwire and would provide an equivalent level of safety. American 
Airlines expressed concern that if the FAA interpreted use of .041 
lockwire as an RC step, the .040 lockwire could easily be mistakenly 
used due to the similarity to the .041 lockwire. The commenter 
requested that the FAA include an exception regarding this issue if 
appropriate.
    The FAA notes that for the purposes of the SDOS actuator, .040 
lockwire will function the same as .041 lockwire. The FAA further notes 
that Boeing Special Attention Requirements Bulletin 737-71-1911 RB, 
Revision 1, dated September 10, 2020, does not specify the use of 
lockwire in an RC step. Therefore, no change to this AD is necessary as 
a result of this comment.

Request To Change Description of the Incidents Prompting This AD

    Boeing requested an update to the SUMMARY and Discussion sections 
of the NPRM, and paragraph (e) of the proposed AD, to clarify that 
there were two different causes and corrective actions.
    The FAA agrees and has revised the Summary, Background, and 
paragraph (e) of this AD to delineate the two corrective actions. The 
Background section of this final rule describes in detail the two 
incidents and how each resulted in the actuator's sudden and hazardous 
extension. To address the cause of each incident, this AD requires two 
actions, both of which are unchanged from the NPRM: (1) Replacing each 
affected SDOS actuator with a new SDOS actuator, and (2) verifying that 
new safety markers are installed in the proper locations.

[[Page 40930]]

Request To Update the Number of Affected U.S. Airplanes

    Boeing stated that the number of affected U.S.-registered airplanes 
identified in the Costs of Compliance section depends on whether the 
NPRM covers only the SDOS attachment issue (in which case Boeing stated 
the number is correct), or also covers the safety marker issue (in 
which case Boeing stated an additional 240 airplanes would be 
affected).
    The FAA notes that since this AD addresses both the SDOS actuator 
attachment issue and the safety marker issue, both types of affected 
SDOS actuators must be replaced, resulting in an additional 240 U.S.-
registered airplanes that would be affected. The estimated cost for 
this AD has been updated to reflect a total of 400 U.S.-registered 
airplanes.

Request To Revise Cost Estimate

    Boeing requested that the FAA revise the Costs of Compliance 
section of the NPRM to correct the labor cost calculation to $425 per 
airplane.
    The FAA agrees that the NPRM provided an incorrect estimate for the 
number of work-hours to replace the SDOS actuators. The FAA has revised 
the costs accordingly in this final rule.

Request To Modify the Affected Part Without Removal

    Southwest Airlines requested clarification as to whether the SDOS 
actuator part number BOE-2001-901H can be changed on wing to part 
number BOE-2001-901J using the General Aerospace Service Bulletin BOE-
2001-901-71-01 referenced in the Boeing Special Attention Service 
Bulletin 737-71-1911, Revision 1, dated September 10, 2020. Southwest 
Airlines stated that it believes it is possible to do so.
    The FAA notes that neither General Aerospace Service Bulletin BOE-
2001-901-71-01, which is referenced in Boeing Special Attention Service 
Bulletin 737-71-1911, nor Boeing Special Attention Requirements 
Bulletin 737-71-1911 RB, Revision 1, both dated September 10, 2020, 
requires removing the SDOS actuator before applying the safety markers. 
No change to this final rule is necessary as a result of this comment.

Request To Clarify the Need for Ongoing Inspections

    Southwest Airlines asked whether the FAA was developing a 
requirement for ongoing inspections to make sure the safety markers are 
still present. The commenter stated that Boeing Special Attention 
Requirements Bulletin 737-71-1911 RB, dated November 26, 2019, does not 
mention inspecting for safety markers after the initial compliance.
    The FAA notes that proper installation of the safety markers is 
intended to be permanent; therefore, no repetitive inspections of the 
safety marker installation are necessary. Because all Model 737 
airplanes powered by LEAP-1B engines have engine fan cowls that, due to 
parts rotability, are subject to reinstallation of affected SDOS 
actuators, those airplanes are subject to the requirements of paragraph 
(j) of this AD, which prohibits the installation of SDOS actuators 
having part numbers BOE-2001-901F and BOE-2001-901H. The FAA has not 
changed this AD as a result of the comment.

Request To Include Instructions for Examination of Spare Parts

    United Airlines requested clarification of actions required for 
spare parts. The commenter asserted that spare parts should be handled 
in the same manner as parts found installed on the aircraft once they 
are removed and that Paragraph 3.B., Work Instructions, provided in the 
Boeing Special Attention Service Bulletin 737-71-1911, dated November 
26, 2019, are intended to be performed at an aircraft level with some 
steps not being applicable.
    The FAA disagrees and has not changed the AD with regard to this 
request. ADs in general do not apply directly to spare parts because 
under 14 CFR part 39, ADs are legally enforceable rules that apply only 
to products such as airplanes, and not to parts that are not installed 
on an airplane. The FAA can, by AD, prohibit or condition the 
installation of a part on a product. This AD prohibits the installation 
of SDOS actuators having part numbers BOE-2001-901F and BOE-2001-901H. 
However, the FAA notes that Boeing Special Attention Service Bulletin 
737-71-1911, Revision 1, dated September 10, 2020, includes non-
mandatory information on how to contact General Aerospace for shipping 
instructions for SDOS actuator part number BOE-2001-901F, although this 
AD does not require the return of any parts. Further, the BOE-2001-901H 
SDOS actuators can be changed to BOE-2001-901J SDOS actuators.

Conclusion

    The FAA reviewed the relevant data, considered the comments 
received, and determined that air safety and the public interest 
require adopting this final rule with the changes described previously 
and minor editorial changes. The FAA has determined that these minor 
changes:
     Are consistent with the intent that was proposed in the 
NPRM for addressing the unsafe condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    The FAA also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this final 
rule.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Special Attention Requirements Bulletin 
737-71-1911 RB, Revision 1, dated September 10, 2020. This service 
information describes procedures for replacing each affected SDOS 
actuator with a new SDOS actuator and verifying that safety markers are 
installed. 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 the ADDRESSES section.

Costs of Compliance

    The FAA estimates that this AD affects 400 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                      Estimated Costs for Required Actions
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                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
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Replace SDOS actuator.................  5 work-hours x $85 per               * $          * $425      * $170,000
                                         hour = $425.
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* The FAA has received no definitive data that would enable the agency to provide parts cost estimates for the
  actions specified in this proposed AD.


[[Page 40931]]

    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, some or all of the costs of 
this AD may be covered under warranty, thereby reducing the cost impact 
on affected persons.

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.

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:

2021-13-18 The Boeing Company: Amendment 39-21623; Docket No. FAA-
2020-0333; Product Identifier 2020-NM-015-AD.

(a) Effective Date

    This AD is effective September 3, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737 airplanes 
powered by LEAP-1B engines, certificated in any category.

(d) Subject

    Air Transport Association (ATA) of America Code 71, Powerplant.

(e) Unsafe Condition

    This AD was prompted by reports of inadvertent release of the 
spring energy of certain spring door opening system (SDOS) 
actuators. The FAA is issuing this AD to address possible separation 
of the SDOS actuator and visual obstruction of the SDOS actuator 
safety marker, which, during maintenance, can cause injury to 
maintenance personnel or damage to the airplane.

(f) Compliance

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

(g) Required Actions

    For airplanes identified in Boeing Special Attention 
Requirements Bulletin 737-71-1911 RB, Revision 1, dated September 
10, 2020: At the applicable times specified in the ``Compliance'' 
paragraph of Boeing Special Attention Requirements Bulletin 737-71-
1911 RB, Revision 1, dated September 10, 2020, except as specified 
by paragraph (h) of this AD, do all applicable actions identified 
in, and in accordance with, the Accomplishment Instructions of 
Boeing Special Attention Requirements Bulletin 737-71-1911 RB, 
Revision 1, dated September 10, 2020.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Special Attention Service 
Bulletin 737-71-1911, Revision 1, dated September 10, 2020, which is 
referred to in Boeing Special Attention Requirements Bulletin 737-
71-1911 RB, Revision 1, dated September 10, 2020.

(h) Exception to Service Information Specifications

    Where Boeing Special Attention Requirements Bulletin 737-71-1911 
RB, Revision 1, dated September 10, 2020, uses the phrase ``the 
original issue date of Requirements Bulletin 737-71-1911 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 Special Attention 
Requirements Bulletin 737-71-1911 RB, dated November 26, 2019.

(j) Parts Installation Prohibition

    As of the effective date of this AD, no person may install on 
any airplane an SDOS actuator having part number BOE-2001-901F or 
BOE-2001-901H.

(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 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 (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 local flight standards district office/certificate holding 
district 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 Rose Len, Aerospace 
Engineer, Propulsion Section, FAA, Seattle ACO Branch, 2200 South 
216th St., Des Moines, WA 98198; phone and fax: 206-231-3604; 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 Special Attention Requirements Bulletin 737-71-1911 
RB, Revision 1, dated September 10, 2020.
    (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; internet https://www.myboeingfleet.com.
    (4) You may view this service information at the FAA, 
Airworthiness Products Section,

[[Page 40932]]

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

    Issued on June 18, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-16174 Filed 7-29-21; 8:45 am]
BILLING CODE 4910-13-P