[Federal Register Volume 85, Number 35 (Friday, February 21, 2020)]
[Rules and Regulations]
[Pages 10036-10042]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-03427]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0399; Product Identifier 2018-NM-149-AD; Amendment 
39-19823; AD 2020-03-10]
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 The 
Boeing Company Model 737 series airplanes, except for Model 737-100, -
200, -200C, -300, -400, and -500 series airplanes. This AD was prompted 
by reports of separation of the lower aft wing-to-body fairing panel 
194E (``fairing panel 194E'') during flight, due to worn or damaged 
nutplates on the

[[Page 10037]]

support structure. This AD requires repetitive inspections for 
discrepancies of fairing panel 194E, wheel well panel 193D, and support 
structure, and related investigative and corrective actions if 
necessary. This AD also requires rework of the panels and support 
structure, which terminates the repetitive inspections. The FAA is 
issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective March 27, 2020.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of March 27, 
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, Transport Standards 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-2019-
0399.

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-2019-
0399; 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 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: Michael Bumbaugh, Aerospace Engineer, 
Airframe Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3522; 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 The Boeing Company 
Model 737 series airplanes, except for Model 737-100, -200, -200C, -
300, -400, and -500 series airplanes. The NPRM published in the Federal 
Register on June 19, 2019 (84 FR 28429). The NPRM was prompted by 
reports of separation of the lower aft wing-to-body fairing panel 194E 
(``fairing panel 194E'') during flight, due to worn or damaged 
nutplates on the support structure. In the NPRM, the FAA proposed to 
require repetitive inspections of fairing panel 194E, wheel well panel 
193D, and support structure for discrepancies, and required related 
investigative and corrective actions if necessary. The NPRM also 
proposed to require rework of the panels and support structure, which 
would terminate the repetitive inspections.
    The FAA is issuing this AD to address separation of fairing panel 
194E.

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.

Support for the NPRM

    One individual and United Airlines (United) stated support for the 
NPRM. United, commenting that they had no records of the unsafe 
condition, also concurred with the intent of the NPRM. In a subsequent 
comment submission, United also requested several changes, which are 
addressed later in this comment disposition.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that accomplishing the Supplemental 
Type Certificate (STC) ST00830SE, the installation of blended or split 
scimitar winglets, does not affect the ability to accomplish the 
actions specified in the NPRM, which affect the lower aft wing-to-body 
area.
    The FAA agrees with the commenter. The FAA has added paragraph 
(c)(2) to this AD to state that installation of STC ST00830SE does not 
affect the ability to accomplish the actions required by this final 
rule. Therefore, for airplanes on which STC ST00830SE is installed, a 
``change in product'' alternative method of compliance (AMOC) approval 
request, per 14 CFR 39.17, is not necessary to comply with the 
requirements of this AD.

Request To Delay Issuance of Final Rule Until Service Information Is 
Revised

    Southwest Airlines (SWA) and Delta Airlines (DAL) asked that the 
final rule not be issued until a revision of the Boeing Special 
Attention Service Bulletin 737-53-1307, dated January 12, 2012, has 
been issued.
    SWA stated that the referenced service information should be 
revised and released to include clarification on the fastener and 
hardware installation requirements to prevent the potential of 
overtorquing the fasteners and causing additional damage to the panels 
and the support structure. SWA noted that the referenced service 
information provides minimum and maximum torque values, but added that 
an Aircraft Maintenance Manual (AMM) referenced in the service 
information provides different torque values, including a higher 
maximum torque value. SWA added that the referenced service information 
does not provide an installation torque for the fasteners and nutplate, 
but stated that Boeing told it to use 29 to 31 in-lb.
    The FAA notes that the torque values specified in Boeing Special 
Attention Service Bulletin 737-53-1307, dated January 12, 2012, must, 
as a result of this AD, be complied with. When those values contradict 
the values specified in the AMM referenced in the service information, 
the torque minimum and maximum specified in Boeing Special Attention 
Service Bulletin 737-53-1307, dated January 12, 2012, must be used, 
since it is now mandatory.
    SWA also stated that the guidance currently provided in the 
referenced service information does not include provisions to address 
the open rivet holes after the removal of the existing nutplates. SWA 
added that the referenced service information provides guidance for 
repair of the fairing panel support structure in accordance with 
structural repair manual (SRM) 53-60-71, but that SRM 53-60-71, Repair 
2, specifies installing a repair strap at the damaged nutplate 
location, which SWA states would interfere with the ability to install 
the support/plate assemblies at the nutplate locations specified in the 
referenced service information. SWA concluded that the referenced 
service information cannot be accomplished without multiple deviations, 
and requested clarification whether these deviations would require an 
AMOC.
    DAL also stated that paragraph (g)(1) of the proposed AD would 
require doing a general visual inspection for discrepancies of fairing 
panel 194E, wheel well panel 193D, and support structure, in accordance 
with Part 1 and Part 2 of the Accomplishment Instructions of Boeing 
Special Attention Service Bulletin 737-53-1307, dated January 12, 2012; 
however, Part 1 of the referenced service information does not provide 
any instructions to inspect or

[[Page 10038]]

repair the 193D panel, so it would be necessary to request an AMOC.
    Regarding DAL's suggestion that the referenced service information 
does not provide any instructions to inspect or repair the 193D panel, 
the FAA notes that the torque check specified in figure 1, step 1 of 
the referenced service information is an inspection of the 193D panel. 
If any repairs are needed that are not addressed in the referenced 
service information, operators will need to request an AMOC.
    DAL also stated that it has already performed the actions specified 
in Boeing Special Attention Service Bulletin 737-53-1307, dated January 
12, 2012, on three Model C-40A (737-700C military variant) airplanes 
and found that previous installation of repair parts per SRM 53-60-71 
for damage at the nutplates will interfere with parts installed using 
the instructions provided in the referenced service information. DAL 
also stated that the referenced service information does not currently 
take into account that existing repairs on the fairing support 
structure may inhibit compliance with the service information as 
written, which will drive the need for AMOCs.
    Regarding DAL's comment that the referenced service information 
does not take into account existing repairs, the FAA notes that an AD 
cannot predict every change in product that is different than type 
design; therefore DAL would need to request an AMOC if an existing 
repair prevented it from accomplishing the actions required by this AD.
    The FAA acknowledges the commenters' concerns regarding the need to 
clarify the service information for the specific scenarios raised and 
is working with Boeing to address these concerns as soon as possible. 
If this effort culminates in a global AMOC that is approved by the FAA 
before the 24-month compliance time for the inspection has passed, and 
that AMOC addresses all the necessary deviations, commenters and other 
affected operators would not need to seek a separate AMOC. Therefore, 
the FAA has added paragraph (j)(1) to this AD to provide operators with 
information regarding how to address any actions in the service 
information that cannot be accomplished.
    In light of the critical nature of the identified unsafe condition 
(i.e., the possible separation of the lower aft wing-to-body fairing 
panel during flight) and the scope of affected airplanes, the FAA does 
not consider it warranted to delay the issuance of this final rule. If 
Boeing provides a revision to Boeing Special Attention Service Bulletin 
737-53-1307, dated January 12, 2012, the FAA will review it in 
consideration of an AMOC to this AD or may consider future rulemaking 
action.

Request To Specify Applicability of a Note in the Service Information

    DAL noted that figure 5, sheet 5, of the referenced service 
information includes note (b), which specifies procedures for 
installing a panel but is not referenced in the instructions for figure 
5, and DAL does not know where that note should be applied.
    The FAA clarifies that note (b) in figure 5, sheet 5 applies to 
steps 8 and 10 of figure 5 in Boeing Special Attention Service Bulletin 
737-53-1307, dated January 12, 2012. The FAA has added paragraph (j)(2) 
of this AD to include this information.

Request To Clarify Cleaning Procedures

    SWA and DAL requested that the cleaning procedures in Boeing 
Special Attention Service Bulletin 737-53-1307, dated January 12, 2012, 
be clarified. The commenters stated that although the referenced 
service information refers to cleaning procedures ``CM3'' and ``CM5'' 
in standard wiring practices manual (SWPM) 20-20-00, those procedures 
do not exist. SWA added that SWPM 20-20-00, as revised on June 1, 2015, 
lists what SWA considers to be corresponding cleaning procedures in 
paragraphs 2.E and 2.C. DAL suggested allowing operators to use 
standard cleaning procedures.
    The FAA does not agree that any standard cleaning procedure would 
be acceptable, however the FAA agrees to clarify the acceptable 
cleaning procedures. The FAA has added paragraph (j)(3) to this AD to 
clarify that where note (a) to figure 5 of Boeing Special Attention 
Service Bulletin 737-53-1307, dated January 12, 2012 specifies to clean 
``per abrasive cleaning method CM5'' and refers to ``SWPM 20-20-00,'' 
for this AD operators must use ``cleaning procedure 3'' and refer to 
``SWPM 20-20-00.'' The FAA has also added paragraph (j)(4) to this AD 
to clarify that where note (a) to figure 5 of Boeing Special Attention 
Service Bulletin 737-53-1307, dated January 12, 2012, specifies to 
clean ``per solvent cleaning method CM3,'' and refers to ``SWPM 20-20-
00,'' for this AD operators must use ``cleaning procedure 5'' and refer 
to ``SWPM 20-20-00.''

Request To Limit Inspection Area for Certain Airplanes

    SWA requested that the FAA revise paragraph (g)(2) of the proposed 
AD such that for line numbers 3533 and subsequent that have not altered 
the type design since the original airworthiness certificate, the 
inspection should be limited to an external visual inspection of the 
panels only. SWA noted that, for those airplanes, the rework to the 
support structure can be verified based upon the number of attachments 
on the panels.
    The FAA agrees with the commenter's request because, for those 
airplanes, an equivalent change to the support structure and panels was 
made in production, and this change can be verified by an external 
visual inspection. The FAA has revised paragraphs (g)(1) and (2) of the 
proposed AD and added paragraph (g)(3) to specify that, for airplanes 
having line numbers 3533 and subsequent that have not altered the type 
design since the issuance of an original airworthiness certificate or 
an original export certificate of airworthiness, an external visual 
inspection of fairing panel 194E and wheel well panel 193D may be used 
to verify the correct panel configuration, provided it can be 
determined that fairing panel 194E, wheel well panel 193D, and the 
support structure have the number and type of attachments specified in 
the post-reworked configuration of Boeing Special Attention Service 
Bulletin 737-53-1307, dated January 12, 2012.

Request To Clarify Repairs That Require an AMOC

    SWA and DAL commented on the need for an AMOC for repairs to the 
panel and substructure interface, which are classified as secondary 
structure.
    SWA stated that the subject structure is classified as secondary, 
non-FCBS (fatigue critical baseline structure) in 737NG SRM 51-00-04, 
and repairs to the panel and substructure that do not adversely alter 
the panel to the substructure interface should not require an AMOC to 
the AD (i.e., as long as the required number and type of fasteners 
attaching the panel to the substructure remain the same). SWA added 
that requiring an AMOC would necessitate the original equipment 
manufacturer (OEM) to generate an FAA Form 8100-9 for a minor repair, 
which is in conflict with FAA Order 8100-17B and Boeing Service Letter 
737-SL-51-041-E.
    DAL stated that repairs to AD-related secondary structure per SRM 
51-70 are minor repairs (SRM 51-00-04) and should not require an AMOC 
or additional approvals for any deviations to the SRM repairs. DAL 
added that repairs to the panel or substructure that do not adversely 
affect or inhibit the intended function of the modification of the 
panel-to-substructure interface

[[Page 10039]]

should continue to be done in accordance with approved data or data 
that is acceptable to the Administrator with no additional approval or 
AMOC required.
    The FAA acknowledges the commenters' concerns and infers that the 
commenters are requesting that the agency clarify the requirements of 
paragraph (g) of this AD regarding the need for AMOCs. The FAA agrees 
to clarify this paragraph. Repairs or alterations to the panel that do 
not interfere with the requirements of this AD will not require an 
AMOC. The FAA has added paragraph (g)(4) of this AD to specify that 
repairs that do not affect the number or type of fasteners necessary 
for the post-reworked configuration may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining an AMOC.

Request To Clarify Certain Procedures in the Referenced Service 
Information

    SWA and DAL asked that Boeing Special Attention Service Bulletin 
737-53-1307, dated January 12, 2012, be clarified to define the 
procedures for panels 194E and 193D that have not been reworked.
    SWA stated that the proposed AD does not allow fairing panel 194E 
or wheel well panel 193D to be installed on any airplane after the 
effective date of the AD, if the panels have not been reworked. SWA 
noted that this would prohibit normal maintenance of the panels prior 
to implementing the terminating action. SWA requested that the proposed 
AD be revised to add a grace period for normal maintenance of 
unmodified panels prior to accomplishment of the terminating action. 
SWA added that the referenced service information does not provide part 
numbers for the reworked panels, and should be revised in order to 
control the part number of the modified panels.
    DAL stated that the referenced service information should be 
revised because it does not identify a post-service bulletin part 
number in order to track and maintain the fairing panel configuration. 
DAL recommended that it be revised before issuance of the final rule to 
ensure a separate part number is created for tracking of the attachment 
configuration. DAL noted that as the proposed AD is currently written, 
any panel installed after the effective date of the AD will drive 
immediate full incorporation of the referenced service information. DAL 
believes that paragraph (i) of the proposed AD would force immediate 
compliance in the event of non-routine maintenance action or just 
accomplishment of paragraph (g)(1) of the proposed AD, either of which 
may not be associated with the identified unsafe condition, although 
the proposed compliance time for the terminating action is 72 months. 
The proposed AD would have, at paragraph (i), prohibited installation 
of fairing panel 194E ``unless fairing panel 194E, wheel well panel 
193D, and the support structure have the number and type of attachments 
specified in the post-reworked configuration of Boeing Special 
Attention Service Bulletin 737-53-1307, dated January 12, 2012.'' DAL 
suggested that paragraph (i) be changed to prohibit installation of 
fairing panel 194E ``unless a general visual inspection for 
discrepancies has been accomplished on fairing panel 194E, wheel well 
panel 193D, and the support structure, within the compliance times 
specified in SB 737-53-1307 Paragraph 1.E.''
    The FAA agrees that some clarification is necessary. Boeing Special 
Attention Service Bulletin 737-53-1307, dated January 12, 2012, already 
provides a method of identifying modified panels in figure 5, step 9. 
The FAA has revised paragraph (i) of this AD to include separate 
requirements for airplanes with an original airworthiness certificate 
or an original export certificate of airworthiness dated after the 
effective date of this AD, for airplanes with an original airworthiness 
certificate or an original export certificate of airworthiness dated 
before the effective date of this AD, and for airplanes on which the 
terminating action has been done.

Request To Define Final Configuration of the Panel-to-Substructure

    SWA asked that the final configuration of the panel-to-substructure 
interface be defined in the subject of the proposed AD, rather than 
referenced in Boeing Special Attention Service Bulletin 737-53-1307, 
dated January 12, 2012, in its entirety, by the individual 
configuration of the discrepant panels, or the associated substructure. 
SWA noted that the subject structure is classified as secondary, non-
FCBS in 737NG SRM 51-00-04; therefore, typical repairs given in 737NG 
SRM 51-70 apply to the panel and the associated substructure. SWA 
stated that as there is no specific section in the published SRM for 
the discrepant structure, these typical SRM repairs can be accomplished 
with no additional approval from the operator or the applicable 
regulatory body. SWA and DAL both noted that there are no provisions to 
alert the mechanic that the structure is subject to an AD.
    The FAA acknowledges the commenter's concern; however, the agency 
relies on the referenced service information to define the 
modification, and operators must ensure that they are meeting all the 
requirements of any applicable AD. As noted in prior comments, there 
are a significant number of other SRM repairs or modifications that can 
be present and alter the final configuration of the support structure 
or panel. It would be difficult if not impossible to address all 
possible individual configurations in this AD. Under the provisions of 
paragraph (k) of this AD, the FAA will consider requests for approval 
of other SRM repairs or modifications if sufficient data are submitted 
to substantiate that the change would provide an acceptable level of 
safety. The AD has not been changed in this regard.

Request To Revise Compliance Time for the Inspections

    SWA, DAL, and United asked that the compliance time for the 
inspections be extended.
    United stated that the proposed compliance time of 24 months for 
the initial general visual inspection, with a repetitive interval of 
1,000 flight cycles thereafter, would require operators performing both 
the inspection and the terminating action in a line environment. United 
asked that the FAA and Boeing to consider revising the AD and service 
information to allow an initial detailed visual inspection within 36 
months and the repeat inspections every 4,000 flight cycles thereafter, 
in lieu of the proposed inspection method and compliance times. United 
noted that this would allow more time to properly schedule the 
airplanes in a heavy check environment where both the inspection and 
rework per the referenced service information can be easily 
accomplished.
    DAL stated that a 36-month compliance time for the initial 
inspection would provide a better opportunity to catch the initial 
inspection at a C-check (a type of heavy check) and not drive special 
visits. DAL noted that waiting on approvals if damage is found would 
cause significant delays.
    The FAA does not agree with the commenters' requests to extend the 
compliance time for the initial and repetitive inspections. In 
developing an appropriate compliance time for this action, the FAA 
considered not only the safety implications of the identified unsafe 
condition, but also the average

[[Page 10040]]

utilization rate of the affected fleet, the availability of required 
parts, and the practical aspect of accomplishing the required 
inspections within a period of time that corresponds to the normal 
scheduled maintenance for most affected operators. Further, United did 
not provide substantiation in support of its request to increase 
inspection intervals with a detailed visual inspection. The FAA has not 
changed this AD in this regard.
    SWA stated that the inspection specified in paragraph (g) and the 
terminating action specified in paragraph (h) of the proposed AD 
require compliance within a calendar time of 24 months and 72 months of 
the AD effective date, respectively; however, due to the unknown 
return-to-service (RTS) dates of the Boeing Model 737-8 and -9 (MAX) 
airplanes, SWA is awaiting delivery of several airplanes. SWA 
recommended the compliance thresholds be defined based upon total 
flight cycles, in order to alleviate the concerns regarding the MAX 
airplanes' RTS.
    The FAA does not agree to define the compliance thresholds based on 
total flight cycles. Consistent with 14 CFR 39.7, no person will be in 
violation of this AD because the MAX airplanes are not currently 
operated. The actions required by this AD can be accomplished before 
the airplanes' RTS. In addition, the actions required by this AD will 
be accomplished on all new MAX airplanes before delivery. Therefore, 
this AD has not been changed in this regard.

Request To Change Applicability

    Boeing and United asked that the applicability in the proposed AD 
be changed.
    Boeing noted that there is a difference between Boeing Special 
Attention Service Bulletin 737-53-1307, dated January 12, 2012, and the 
proposed AD in capturing airplane effectivity. Boeing stated that there 
may be some instances where operators are rotating parts outside of 
type design, beyond effectivity limits, or having ``pre-mod'' panels 
installed on airplane configurations where service bulletins and design 
changes have already been incorporated. Boeing noted that it 
understands the FAA's concerns with the possibility of parts being 
rotated outside the effectivity contained in the referenced service 
information, and would like to seek an alternative solution to address 
these FAA concerns. Boeing recommended that it and the FAA collaborate 
with the company's airline partners, other OEMs, and other Civil 
Aviation Authorities (CAAs) to develop an action to implement safe, 
fair, and consistent policy to address the company's concerns on 
rotable parts for the industry. Boeing concluded that the applicability 
of the proposed AD extends beyond that specified in the referenced 
service information, and suggested that rotable parts be addressed 
separately.
    United stated that the proposed airplane effectivity range in the 
proposed AD falls outside of the effectivity specified in Boeing 
Special Attention Service Bulletin 737-53-1307, dated January 12, 2012. 
United added that the specified action is to add airplanes with the new 
panels already incorporated at the OEM to the current effectivity range 
given in the referenced service information, for a one-time inspection 
verification. (The range is for line numbers (L/Ns) 3533 and subsequent 
with an original airworthiness certificate or an original export 
certificate of airworthiness dated on or before the effective date of 
this AD.) United noted that the reason for the inspection verification 
is that the FAA believes that since these parts are rotable, there is a 
possibility the older parts could be installed on future airplanes. 
United respectfully disagreed on this action and requested that the FAA 
revisit this matter and keep the effectivity range limited to those 
airplanes identified in the referenced service information. United 
disagreed with the FAA because even though the subject parts are 
rotable, United controls and maintains all its interchangeability and 
installation of these panels through production drawings and aircraft 
manuals, such as the illustrated parts catalog (IPC), which have always 
shown the latest up-to-date panels affected for L/Ns 3533 and 
subsequent. United concluded that to this day, it has never had a 
parts-departing-airplane (PDA) incident with the subject panels 193D 
and 194E on any of its Model 737-NG airplanes.
    The FAA does not agree to change the applicability. The affected 
parts are rotable parts, and the FAA has determined that, regardless of 
operator diligence, these parts could later be installed on airplanes 
that were initially delivered with acceptable parts, thereby subjecting 
those airplanes to the unsafe condition. The FAA has not changed this 
AD in this regard.

Request To Allow the Use of Later Revisions of the Service Information

    An individual asked the FAA to modify the AD to allow later 
revisions of the referenced service information. He said this would 
ensure that operators are promptly in compliance with obligations and 
all maintenance is certified to the latest approved version of the 
maintenance data. The commenter also stated that this would remove the 
requirement for the proposed AD to be revised to reflect changes in 
revised service information, and to eliminate the need to request an 
AMOC to approve the use of the revised service information, again 
reducing the delay in implementing a revision and reducing the 
maintenance costs associated with the issuance of an AMOC. The 
commenter added that the European Union Aviation Safety Agency (EASA) 
already incorporates the ``or later revision'' statement in any EASA 
AD. The commenter noted that this would demonstrate a further 
harmonization of regulatory control.
    The FAA does not agree to change the AD to allow the use of later 
revisions of the service information. The FAA may not require 
compliance with a document that does not yet exist. In general terms, 
the FAA is required by Office of the Federal Register (OFR) regulations 
for approval of materials incorporated by reference, as specified in 1 
CFR 51.1(f), to either publish the service document contents as part of 
the actual AD language; or submit the service documents to the OFR for 
approval as referenced material, in which case the FAA may only refer 
to such material in the text of an AD. The AD may refer to the service 
document only if the OFR approved it for incorporation by reference. 
See 1 CFR part 51. To allow operators to use later revisions of the 
referenced document (issued after publication of the final rule), 
either the FAA must revise the AD to reference specific later 
revisions, or operators must request approval to use later revisions as 
an AMOC with this AD under the provisions of paragraph (k) of this AD. 
The AD has not been changed regarding this issue.

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.

[[Page 10041]]

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Special Attention Service Bulletin 737-53-
1307, dated January 12, 2012. This service information describes 
procedures for repetitive inspections of fairing panel 194E, wheel well 
panel 193D, and support structure for discrepancies (including 
incorrect torque at the fasteners and worn and damaged nutplates and 
fastener holes) and corrective actions (including repair and 
replacement of nutplates and fasteners). This service information also 
describes procedures for rework of the panels and support structure, 
including related investigative actions (general visual inspection of 
the panel and support structure for damage) and repair, which together 
would eliminate the need for the repetitive inspections. 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 983 airplanes of U.S. 
registry. The agency estimates the following costs to comply with this 
AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Inspection.......................  8 work-hours x $85               $0  $680 per inspection  Up to $668,440 per
                                    per hour = $680                      cycle.               inspection cycle.
                                    per inspection
                                    cycle.
Rework...........................  25 work-hours x $85               0  $2,125.............  Up to $2,088,875.
                                    per hour = $2,125.
----------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data that would enable the 
agency to provide cost estimates for the on-condition repairs specified 
in this AD.

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 (AD):

2020-03-10 The Boeing Company: Amendment 39-19835; Docket No. FAA-
2019-0399; Product Identifier 2018-NM-149-AD.

(a) Effective Date

    This AD is effective March 27, 2020.

(b) Affected ADs

    None.

(c) Applicability

    (1) This AD applies to all The Boeing Company Model 737 series 
airplanes, certificated in any category, except for Model 737-100, -
200, -200C, -300, -400, and -500 series airplanes.
    (2) Installation of Supplemental Type Certificate (STC) 
ST00830SE does not affect the ability to accomplish the actions 
required by this AD. Therefore, for airplanes on which STC ST00830SE 
is installed, a ``change in product'' alternative method of 
compliance (AMOC) approval request, per 14 CFR 39.17, is not 
necessary to comply with the requirements of this AD.

(d) Subject

    Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

    This AD was prompted by reports of separation of lower aft wing-
to-body fairing panel 194E (``fairing panel 194E'') during flight, 
due to worn or damaged nutplates on wheel well panel 193D and 
support structure. The FAA is issuing this AD to address separation 
of fairing panel 194E.

(f) Compliance

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

(g) Repetitive Inspections and Corrective Actions

    (1) For airplanes with an original airworthiness certificate or 
an original export certificate of airworthiness dated on or before 
the effective date of this AD, except as specified in paragraph 
(g)(2) of this AD: Within 24 months after the effective date of this 
AD, do a general visual inspection for discrepancies of fairing 
panel 194E, wheel well panel 193D, and support structure, and do all 
applicable related investigative and corrective actions, in 
accordance with Part 1 and Part 2 of the Accomplishment Instructions 
of Boeing Special Attention Service Bulletin 737-53-1307, dated 
January 12, 2012. All applicable related investigative and 
corrective actions must be done before further flight. Repeat the 
inspection thereafter at intervals not to exceed 1,000 flight 
cycles.
    (2) For airplanes having line numbers 3533 and subsequent that 
have not altered the type design since the issuance of an original 
airworthiness certificate or an original export certificate of 
airworthiness, an external visual inspection of fairing panel 194E 
and wheel

[[Page 10042]]

well panel 193D may be used to verify the correct panel 
configuration, provided it can be determined that fairing panel 
194E, wheel well panel 193D, and the support structure have the 
number and type of attachments specified in the post-reworked 
configuration of Boeing Special Attention Service Bulletin 737-53-
1307, dated January 12, 2012. If the external inspection shows that 
fairing panel 194E, wheel well panel 193D, and the support structure 
have the number and type of attachments specified in the post-
reworked configuration of Boeing Special Attention Service Bulletin 
737-53-1307, dated January 12, 2012, then the repetitive inspections 
required by paragraph (g)(1) of this AD are terminated.
    (3) For airplanes having line numbers 3533 and subsequent with 
an original airworthiness certificate or an original export 
certificate of airworthiness dated on or before the effective date 
of this AD: If the initial inspection required by paragraph (g)(1) 
of this AD shows that fairing panel 194E, wheel well panel 193D, and 
the support structure have the number and type of attachments 
specified in the post-reworked configuration of Boeing Special 
Attention Service Bulletin 737-53-1307, dated January 12, 2012, then 
the repetitive inspections required by paragraph (g)(1) of this AD 
are terminated. The requirements of paragraph (i) of this AD 
continue to apply.
    (4) Repairs to fairing panel 194E, wheel well panel 193D, or the 
support structure that do not affect the number or type of fasteners 
necessary for the post-reworked configuration may be deviated from 
using accepted methods in accordance with the operator's maintenance 
or inspection program without obtaining approval of an AMOC, 
provided the remaining requirements can be done and the airplane can 
be put back in an airworthy condition.

(h) Terminating Action

    For airplanes with an original airworthiness certificate or an 
original export certificate of airworthiness dated on or before the 
effective date of this AD: Within 72 months after the effective date 
of this AD, do the actions required by paragraph (h)(1) or (2) of 
this AD, as applicable. Accomplishing the actions in paragraph 
(h)(1) or (2) of this AD terminates the repetitive inspections 
required by paragraph (g)(1) of this AD. The requirements of 
paragraph (i) of this AD continue to apply.
    (1) Rework fairing panel 194E, wheel well panel 193D, and the 
support structure, including accomplishment of all applicable 
related investigative actions and repair, in accordance with Part 3 
of the Accomplishment Instructions of Boeing Special Attention 
Service Bulletin 737-53-1307, dated January 12, 2012. All applicable 
related investigative actions and repairs must be done before 
further flight.
    (2) Verify that fairing panel 194E, wheel well panel 193D, and 
the support structure have the number and type of attachments 
specified in the post-reworked configuration of Boeing Special 
Attention Service Bulletin 737-53-1307, dated January 12, 2012.

(i) Parts Installation Limitations

    (1) For airplanes with an original airworthiness certificate or 
an original export certificate of airworthiness dated after the 
effective date of this AD: As of the effective date of this AD, no 
person may install a fairing panel 194E on any airplane identified 
in paragraph (c) of this AD, unless fairing panel 194E, wheel well 
panel 193D, and the support structure have the number and type of 
attachments specified in the post-reworked configuration of Boeing 
Special Attention Service Bulletin 737-53-1307, dated January 12, 
2012.
    (2) For airplanes with an original airworthiness certificate or 
an original export certificate of airworthiness dated on or before 
the effective date of this AD: As of the effective date of this AD, 
a fairing panel l94E with or without the post-reworked configuration 
may be installed on any airplane, provided that the repetitive 
inspections and all applicable related investigative and corrective 
actions required by paragraph (g)(1) of this AD are accomplished.
    (3) For airplanes on which the terminating action required by 
paragraph (h) of this AD has been done: As of the effective date of 
this AD, no person may install a fairing panel 194E on any airplane 
identified in paragraph (c) of this AD unless fairing panel 194E, 
wheel well panel 193D and the support structure have the number and 
type of attachments specified in the post-reworked configuration of 
Boeing Special Attention Service Bulletin 737-53-1307, dated January 
12, 2012.

(j) Exceptions to Service Information Specifications

    (1) If any action(s) in Boeing Special Attention Service 
Bulletin 737-53-1307, dated January 12, 2012, cannot be accomplished 
as specified therein, those action(s) must be accomplished using a 
method approved in accordance with the procedures specified in 
paragraph (k) of this AD.
    (2) Where figure 5 of Boeing Special Attention Service Bulletin 
737-53-1307, dated January 12, 2012, includes note (b), but does not 
specify what steps that note applies to, for this AD, apply note (b) 
to steps 8 and 10 of figure 5 of Boeing Special Attention Service 
Bulletin 737-53-1307, dated January 12, 2012.
    (3) Where note (a) to figure 5 of Boeing Special Attention 
Service Bulletin 737-53-1307, dated January 12, 2012, specifies to 
clean ``per abrasive cleaning method CM5'' and refers to ``SWPM 20-
20-00,'' for this AD use ``cleaning procedure 3'' and refer to 
``SWPM 20-20-00.''
    (4) Where note (a) to figure 5 of Boeing Special Attention 
Service Bulletin 737-53-1307, dated January 12, 2012, specifies to 
clean ``per solvent cleaning method CM3,'' and refers to ``SWPM 20-
20-00,'' for this AD use ``cleaning procedure 5'' and refer to 
``SWPM 20-20-00.''

(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 Michael Bumbaugh, 
Aerospace Engineer, Airframe Section, FAA, Seattle ACO Branch, 2200 
South 216th St., Des Moines, WA 98198; phone and fax: 206-231-3522; 
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 Service Bulletin 737-53-1307, dated 
January 12, 2012.
    (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, Transport 
Standards 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 February 4, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-03427 Filed 2-20-20; 8:45 am]
 BILLING CODE 4910-13-P