Airworthiness Directives; The Boeing Company Airplanes, 38055-38059 [2020-13481]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 85, Number 123 (Thursday, June 25, 2020)]
[Rules and Regulations]
[Pages 38055-38059]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-13481]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0091; Product Identifier 2020-NM-012-AD; Amendment 
39-19916; AD 2020-11-12]
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 
certain The Boeing Company Model 737-8 and 737-9 airplanes. This AD was 
prompted by a report that certain exterior fairing panels on the top of 
the engine nacelle and strut (the thumbnail fairing and mid strut 
fairing panels) may not have the quality of electrical bonding 
necessary to ensure adequate shielding of the underlying wiring from 
the electromagnetic effects of high intensity radiated fields (HIRF), 
which could potentially lead to a dual-engine power loss event and/or 
display of hazardously misleading primary propulsion parameters. This 
AD requires a detailed inspection of the thumbnail fairing panels and 
mid strut fairing panels for excessive rework of the metallic (aluminum 
foil) inner surface layer, replacement of any excessively reworked 
panels, and modification of the thumbnail fairing assembly to ensure 
adequate bonding. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective July 30, 2020.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of July 30, 
2020.

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-2020-0091.

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-
0091; 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.

FOR FURTHER INFORMATION CONTACT: Christopher Baker, Aerospace Engineer, 
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3552; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    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 737-8 and 737-9 airplanes. The NPRM published in the 
Federal Register on February 26, 2020 (85 FR 11000). The NPRM was 
prompted by a report that certain exterior fairing panels on the top of 
the engine nacelle and strut (the thumbnail fairing and mid strut 
fairing panels) may not have the quality of electrical bonding 
necessary to ensure adequate shielding of the underlying wiring from 
the electromagnetic effects of HIRF, which could potentially lead to a 
dual-engine power loss event and/or display of hazardously misleading 
primary propulsion parameters. The NPRM proposed to require a detailed 
inspection of the thumbnail fairing panels and mid strut fairing panels 
for excessive rework of the metallic (aluminum foil) inner surface 
layer, replacement of any excessively reworked panels, and modification 
of the thumbnail fairing assembly to ensure adequate bonding.
    The FAA is issuing this AD to address this condition, which could 
result in a forced off-airport landing or excessive flightcrew 
workload.

Comments

    The FAA gave the public the opportunity to participate in 
developing this final rule. The FAA received comments from several 
organizations and individuals. The following discussion presents the 
comments

[[Page 38056]]

received on the NPRM and the FAA's response to each comment.

Support for the NPRM

    The Air Line Pilots Association, International (ALPA) and three 
individuals expressed support for the NPRM.

Request To Exclude Certain Airplanes From the AD's Applicability

    United Airlines (UAL) requested that the proposed AD be revised to 
exclude airplanes that have not been delivered. UAL noted that the 
proposed AD would apply to all Model 737-8 and 737-9 airplanes included 
in line numbers 5602 through 7901, which is beyond the effectivity of 
Boeing Special Attention Service Bulletin 737-54-1056, dated December 
11, 2019. UAL reasoned that for airplanes that have not been delivered, 
Boeing would incorporate the intent of the service bulletin at the 
factory, which would provide an equivalent level of safety. UAL 
suggested that if those airplanes are not excluded from the proposed 
AD's applicability, the FAA should provide credit to prevent the need 
for future alternative method of compliance (AMOC) requests.
    The FAA agrees with the commenter, for the reasons the commenter 
provided. The FAA has revised paragraph (c) of this AD to limit the 
applicability to those airplanes identified in Boeing Special Attention 
Service Bulletin 737-54-1056, dated December 11, 2019.

Request To Refer To Correct Part Numbers

    American Airlines (AAL) and UAL requested that the proposed AD be 
revised to correct the part number for the thumbnail fairing. UAL noted 
that Figure 2 and Figure 8 of Boeing Special Attention Service Bulletin 
737-54-1056, dated December 11, 2019, specify certain thumbnail 
fairings, but those figures specify the incorrect part numbers. The 
commenters noted that Boeing issued Information Notice 737-54-1056 IN 
01, dated January 29, 2020, to correct the part numbers. This 
Information Notice is in the docket for this rulemaking, attached to 
the comment of Hainan Airlines Aviation Technic (Hainan). UAL added 
that, although the Information Notice specifies the correct ``IS'' part 
numbers, it specifies the wrong ``WAS'' part numbers, and noted that 
Boeing plans to address this in a future Information Notice or service 
bulletin revision. UAL asked that the final rule include an exception 
to allow inspection and installation of thumbnail fairings having the 
correct part number.
    The FAA agrees with the commenters' requests. The FAA has added 
paragraph (h) of this AD to include exceptions to the service 
information; this includes paragraph (h)(1) of this AD, which 
identifies the correct part numbers to be used when accomplishing the 
service instructions. Operators must use part number 313A6110-5, 
313A6110-7, or 313A6110-9 in lieu of part number 311A6111-5, 311A6111-
7, or 311A6111-9 when inspecting or installing affected thumbnail 
fairings. The FAA has also redesignated subsequent paragraphs 
accordingly.

Request To Clarify Rivet Hole Size

    AAL suggested to the FAA that the proposed AD be revised to clarify 
the rivet hole size called out for installing a nutplate. AAL stated 
that note (d) to Figure 4 of Boeing Special Attention Service Bulletin 
737-54-1056, dated December 11, 2019, specifies to drill a hole with a 
diameter of ``0.192--0.196.'' AAL stated that Boeing confirmed the 
rivet hole size will be corrected with a revised service bulletin.
    The FAA agrees that the rivet hole size specified in note (d) to 
Figure 4 of Boeing Special Attention Service Bulletin 737-54-1056, 
dated December 11, 2019, is incorrect. SB 737-54-1056 Revision 1, 
corrects this hole size diameter with the following language: ``(d) 
Drill through Thumbnail Land Assembly with a hole Diameter of 0.097--
0.101.'' The FAA has added paragraph (h)(2) to this AD to clarify the 
correct rivet hole size to use when installing a nutplate.

Request To Clarify the Inspection and Replacement Criteria for Critical 
and Non-Critical Bonding Zones

    Hainan requested that the proposed AD be revised to provide 
clarification regarding the inspection and replacement criteria for 
critical and non-critical bonding zones (which are specified in Step 4 
of Boeing Special Attention Service Bulletin 737-54-1056, dated 
December 11, 2019). Hainan noted that Boeing Information Notice 737-54-
1056 IN 01, dated January 29, 2020, provides clarity regarding the 
inspection and the conditions that require replacement of the panels.
    The FAA agrees with the commenter's request. The FAA has added 
paragraph (h)(3) of this AD to clarify the inspection and replacement 
criteria for critical bonding zones. The FAA has also added paragraph 
(h)(4) of this AD to clarify the inspection and replacement criteria 
for non-critical bonding zones.

Request To Revise Certain Background Information

    Boeing requested that paragraph (e) of the proposed AD as well as 
the SUMMARY and the Discussion section in SUPPLEMENTARY INFORMATION of 
the NPRM be revised to be consistent with the potential aircraft system 
impacts Boeing communicated in reporting this issue to the FAA prior to 
issuance of the NPRM, and to remove any references to an unsafe 
condition resulting from lightning strikes. Boeing stated that the 
descriptions of the potential unsafe conditions in the proposed AD are 
inconsistent with its subject matter expert's evaluation of the safety 
issue. Boeing added that there is not a safety concern in the event of 
a lightning strike, because all of the electrical and electronic 
systems with wiring in the affected area retain sufficient margin 
between their design and qualification levels and the lightning-induced 
transient levels, even with the loss of electrical bonding of the foil-
lined panels in the engine strut. Boeing further noted that the 
proposed AD does not mention the potential for displays of misleading 
primary propulsion parameters on the flight deck displays. Boeing 
stated that the proposed AD inaccurately describes a scenario where 
HIRF or lightning induced on one engine's wiring could cross-couple to 
the opposite engine's wiring via the common avionics system's 
connections. Boeing provided suggestions for revised wording.
    The FAA agrees with the commenter's request for the reasons 
provided. Based on further analysis done after issuance of the NPRM, 
the FAA has determined that lightning strikes are not a safety concern 
for the unsafe condition identified in this AD. The FAA has revised the 
SUMMARY and the Discussion section in SUPPLEMENTARY INFORMATION of this 
final rule as well as paragraph (e) of this AD to incorporate the 
changes requested by Boeing.

Request To Revise Special Flight Permit Conditions

    Boeing requested that the special flight permit language in 
paragraph (i) of the proposed AD be revised to provide guidance on the 
HIRF spectrum of concern to operators. Boeing noted that the potential 
for aircraft systems' exposure to HIRF levels higher than their 
original qualification levels is limited to the frequency range between 
1 MHz and 100 MHz. Boeing stated that operators do not need to consider 
potential HIRF sources outside this frequency spectrum when assessing 
routes for special flight permit requests.

[[Page 38057]]

Boeing added that providing clarification on the frequency range of 
concern would reduce the burden on both operators and the FAA in 
submitting and reviewing special flight permit requests.
    The FAA agrees with the request because the agency has determined 
that only the HIRF frequency range between 1 MHz and 100 MHz is of 
concern. The FAA has revised paragraph (i) of this AD to clarify the 
HIRF frequency range that must be identified when submitting a request 
for a special flight permit.

Request To Change Compliance Time to Before Revenue Flight

    Boeing requested that the compliance time in the proposed AD be 
changed from ``before further flight'' to ``before revenue flight.'' 
Boeing noted that the compliance time in Boeing Special Attention 
Service Bulletin 737-54-1056, dated December 11, 2019, is six months. 
Boeing added that it is revising the service bulletin and plans to 
change the compliance time to ``prior to revenue flight'' in the 
revised service bulletin. Boeing noted that ``prior to revenue flight'' 
aligns with the Boeing safety review board recommendation.
    The FAA disagrees with the commenter's request. Without the safety 
features installed during the modification required by this AD, 
airplanes are exposed to potentially unsafe electromagnetic effects. 
The FAA has included provisions in paragraph (i) of this AD (paragraph 
(h) of the proposed AD) for operators who may need to relocate an 
airplane prior to accomplishing the actions required by this AD. The 
FAA has not changed this AD regarding this issue.

Request To Revise Compliance Time To Include Options

    Hainan requested that the compliance time for the proposed AD be 
revised to ``within six months after the effective date of this AD or 
before further flight, whichever occurs first.'' Hainan noted that 
Boeing recommended a compliance time of within six months after the 
original issue date of Boeing Special Attention Service Bulletin 737-
54-1056, dated December 11, 2019. Hainan suggested that, due to the 
unknown return-to-service dates for the affected airplanes, a revised 
compliance time would allow airlines to plan for the actions required 
by this AD. Hainan pointed out that another recent AD on these same 
airplane models has a compliance time of 24 months.
    The FAA disagrees with the commenter's request. Without the safety 
features installed during the modification required by this AD, 
airplanes are exposed to potentially unsafe electromagnetic effects. 
The FAA notes that the compliance time is designed to ensure the 
actions required by this AD are done before further flight (i.e., 
before the affected airplanes are returned to service), and operators 
may do these actions at any time before further flight. The FAA has not 
changed this AD regarding this issue.

Request To Include a Grace Period

    Hainan requested that the proposed AD be revised to provide a grace 
period for the required modification. Hainan stated that Boeing can 
only provide new panels based on the results of required inspections. 
Hainan suggested that due to the international transportation impacts 
caused by the 2019 Novel Coronavirus, new panels may not be available 
to operators in a timely manner.
    As a result of Hainan's comment, the FAA confirmed in June 2020 
that a sufficient number of required parts will be available from the 
manufacturer to modify the worldwide fleet within the compliance time 
of the NPRM, which is adopted as proposed. However, under the 
provisions of paragraph (j) of this AD, the FAA will consider requests 
for approval of an extension of the 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 
regarding this issue.

Request To Clarify Certain Requirements

    Hainan requested that paragraph (g) of the proposed AD be revised 
to specify ``replacement and modification'' rather than 
``modification.'' Hainan noted that the actions in the proposed AD 
include both modification and replacement.
    Paragraph (g) of the proposed AD specified a detailed inspection 
and the modification as applicable. Replacement is one part of the 
modification, and is required only if excessive rework is found during 
that inspection. Thus, the FAA has determined that specifying 
``replacement and modification'' in paragraph (g) of this AD is not 
necessary, and the agency has not changed this AD regarding this issue.

Request To Revise Wording Regarding Required Steps

    Hainan requested that the wording in paragraph (g) of the proposed 
AD be revised to specify ``Steps 4., 6. or 7. through 9., . . .'' 
instead of ``Steps 4., 6. through 9., inclusive . . . .'' Hainan noted 
that Steps 6. and 7. of Boeing Special Attention Service Bulletin 737-
54-1056, dated December 11, 2019, are two different options for one 
action.
    The FAA acknowledges that Steps 6. and 7. of Boeing Special 
Attention Service Bulletin 737-54-1056, dated December 11, 2019, are 
two options for the same action. However, the FAA notes that this is 
clearly stated in Boeing Special Attention Service Bulletin 737-54-
1056, dated December 11, 2019, which labels Step 6. as ``ACTION 2 
(OPTION 1)'' and Step 7. as ``ACTION 2 (OPTION 2).'' Operators are 
required to do only one of these options to show compliance with this 
AD. The FAA has not changed this AD regarding this issue.

Request To Provide Steps for Deactivating Certain Slats

    AAL suggested to the FAA that the proposed AD be revised to include 
steps to deactivate the slats. AAL noted that Boeing recommended 
deactivating the slats and thrust reversers using the Aircraft 
Maintenance Manual (AMM) as an accepted procedure and stated such 
instructions would be included in a revision of the service 
information.
    The FAA agrees that deactivating the slats prior to accomplishing 
the actions specified in the service bulletin would help to protect any 
maintenance personnel working on that area, and that the AMM provides 
acceptable procedures for deactivating the slats. However, the FAA does 
not agree with making slat deactivation a requirement of this AD, since 
this procedure is not needed to address the unsafe condition. The FAA 
has not changed this AD regarding this issue.

Request To Account for Possible Service Information Revision in the 
Final Rule

    AAL suggested to the FAA that the proposed AD be updated to account 
for a revision of Boeing Special Attention Service Bulletin 737-54-
1056, dated December 11, 2019, if one exists. AAL noted that Boeing 
stated that such a revision is in process and AAL asked if the FAA is 
aware of such a revision.
    The FAA acknowledges that Boeing has informed the agency of its 
intent to issue revised service information. However, that revision has 
not yet been published by Boeing. As stated earlier, the FAA has added 
several exceptions to this AD to correct errors in Boeing Special 
Attention Service Bulletin 737-54-1056, dated December 11, 2019. With 
these exceptions, operators will be able to comply with this AD using 
Boeing Special Attention Service Bulletin 737-54-1056, dated December 
11, 2019.

[[Page 38058]]

Explanation of Additional Change to This AD

    The FAA clarifies that where the AD specifies to perform certain 
``Steps'' of the Boeing service bulletin, such steps refer to the 
numbered actions specified within the Procedures section of the 
Accomplishment Instructions. The FAA has revised paragraph (g) of this 
AD to change the required procedures by not including steps 9 and 12 of 
Boeing Special Attention Service Bulletin 737-54-1056, dated December 
11, 2019. The FAA has determined that these steps, while expected to be 
accomplished, are not required to address the unsafe condition 
identified in this AD and this change makes this AD consistent with 
revision 1 of the Boeing service information.

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 more 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 Service Bulletin 737-54-
1056, dated December 11, 2019. This service information describes 
procedures for a detailed inspection of the thumbnail fairing panels 
and mid strut fairing panels for excessive rework of the metallic 
(aluminum foil) inner surface layer (resulting in foil cuts), 
replacement of any excessively reworked panels, and modification of the 
thumbnail fairing assembly to ensure adequate bonding. Modification 
actions include doing a form-in-place gasket of the thumbnail land 
assemblies; preparing the mating surfaces between the thumbnail fairing 
panel and the left and right thumbnail land assemblies; and doing a 
bond check of the thumbnail fairing panel and the thumbnail land 
assemblies on the left and right side of the thumbnail fairing panel on 
both engines. 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 128 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
               Action                         Labor cost            Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Inspection.........................  5 work-hours x $85 per hour              $0            $425         $54,400
                                      = $425.
----------------------------------------------------------------------------------------------------------------

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

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                Action                           Labor cost             Parts cost         Cost per  product
----------------------------------------------------------------------------------------------------------------
Modification.........................  Up to 7 work-hours x $85 per              (*)  Up to $595.*
                                        hour = Up to $595.
----------------------------------------------------------------------------------------------------------------
* The FAA has received no definitive data that would enable the agency to provide parts cost estimates for the
  on-condition actions specified in this AD.

    According to the manufacturer, all of the costs of this AD will be 
covered under warranty, thereby reducing the cost impact on affected 
operators. The FAA does not control warranty coverage for affected 
operators. As a result, the FAA has included all known costs in the 
cost estimate.

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.

[[Page 38059]]

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):

2020-11-12 The Boeing Company: Amendment 39-19916; Docket No. FAA-
2020-0091; Product Identifier 2020-NM-012-AD.

(a) Effective Date

    This AD is effective July 30, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-8 and 737-9 
airplanes, certificated in any category, as identified in Boeing 
Special Attention Service Bulletin 737-54-1056, dated December 11, 
2019.

(d) Subject

    Air Transport Association (ATA) of America Code 54, Nacelles/
pylons.

(e) Unsafe Condition

    This AD was prompted by a report that certain exterior fairing 
panels on the top of the engine nacelle and strut (the thumbnail 
fairing and mid strut fairing panels) may not have the quality of 
electrical bonding necessary to ensure adequate shielding of the 
underlying wiring from the electromagnetic effects of high intensity 
radiated fields (HIRF), which could potentially lead to a dual-
engine power loss event and/or display of hazardously misleading 
primary propulsion parameters. The FAA is issuing this AD to address 
this condition, which could result in a forced off-airport landing 
or excessive flightcrew workload.

(f) Compliance

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

(g) Detailed Inspection and Modification

    Before further flight, do a detailed inspection of the thumbnail 
fairing panels and mid strut fairing panels for excessive rework of 
the metallic (aluminum foil) inner surface layer, and, before 
further flight, do the modification as applicable in accordance with 
Steps 4., 6. through 8. inclusive, and 11. of the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 737-54-
1056, dated December 11, 2019.

(h) Exceptions to Service Information Specifications

    (1) Where Boeing Special Attention Service Bulletin 737-54-1056, 
dated December 11, 2019, specifies thumbnail fairings having part 
number ``311A6111-5 or 311A6111-7 or 311A6111-9,'' for this AD use 
part number ``313A6110-5 or 313A6110-7 or 313A6110-9.''
    (2) Where note (d) to Figure 4 of Boeing Special Attention 
Service Bulletin 737-54-1056, dated December 11, 2019, specifies to 
drill a hole with a diameter of ``0.192-0.196,'' for this AD the 
hole diameter must be ``0.097-0.101.''
    (3) For inspections of critical bonding areas, as specified in 
Step 4.a. of the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 737-54-1056, dated December 11, 2019, any 
panel with cumulative foil cut lengths greater than 4.0 inches 
within any 12.0 inches in length must be replaced; any panel with a 
foil cut gap greater than 0.25 inch also must be replaced.
    (4) For inspections of non-critical bonding areas, as specified 
in Step 4.b. of the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 737-54-1056, dated December 11, 2019, any 
panel with cumulative foil cut lengths greater than 12.0 inches 
within a 12.0-inch by 12.0-inch area must be replaced; any panel 
with a foil cut gap greater than 0.25 inch also must be replaced.

(i) Special Flight Permit

    Special flight permits, as described in 14 CFR 21.197 and 
21.199, may be issued to operate the airplane to a location where 
the requirements of this AD can be accomplished, but concurrence by 
the Manager, Seattle ACO Branch, FAA, is required before issuance of 
the special flight permit. Requests for a special flight permit must 
be submitted to the FAA with a description of the electromagnetic 
field radiation sources (type, location, frequency, and power level) 
along the planned route. Only electromagnetic field radiation 
sources operating in the frequency spectrum between 1 MHz and 100 
MHz need to be identified when submitting a special flight permit 
request (common examples of such sources include, but are not 
limited to, short wave radio towers, FM radio towers, and some TV 
broadcast transmitters). Send requests for a special flight permit 
to the person identified in paragraph (k) of this AD.

(j) 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 (k) 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.

(k) Related Information

    For more information about this AD, contact Christopher Baker, 
Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 
2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-
3552; email: [email protected].

(l) 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 Service Bulletin 737-54-1056, dated 
December 11, 2019.
    (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, 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 11, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-13481 Filed 6-24-20; 8:45 am]
BILLING CODE 4910-13-P