Document ID: FAA-2019-0705-0011
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: The Boeing Company Airplanes
Posted Date: 2020-05-01T04:00Z

[Federal Register Volume 85, Number 85 (Friday, May 1, 2020)]
[Proposed Rules]
[Pages 25348-25352]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-09114]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0705; Product Identifier 2019-NM-098-AD]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Supplemental notice of proposed rulemaking (SNPRM); reopening 
of comment period.

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SUMMARY: The FAA is revising an earlier proposal for certain The Boeing 
Company Model 737-600, -700, -700C, -800, and -900 series airplanes. 
This action revises the notice of proposed rulemaking (NPRM) by 
revising certain inspections to provide the correct thickness callouts 
for the fuselage skin and bear strap. The FAA is proposing this 
airworthiness directive (AD) to address the unsafe condition on these 
products. Since these actions would impose an additional burden over 
that in the NPRM, the FAA is reopening the comment period to allow the 
public the chance to comment on these changes.

DATES: The comment period for the NPRM published in the Federal 
Register on October 1, 2019 (84 FR 52047), is reopened.
    The FAA must receive comments on this SNPRM by June 15, 2020.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    For service information identified in this SNPRM, contact Boeing 
Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 
2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; phone: 
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-2019-
0705.

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-
0705; 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 SNPRM, the regulatory evaluation, any comments received, and other 
information. The street address for Docket Operations is listed above. 
Comments will be available in the AD docket shortly after receipt.

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: 
michael.bumbaugh@faa.gov.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed

[[Page 25349]]

under the ADDRESSES section. Include ``Docket No. FAA-2019-0705; 
Product Identifier 2019-NM-098-AD'' at the beginning of your comments. 
The FAA specifically invites comments on the overall regulatory, 
economic, environmental, and energy aspects of this SNPRM. The FAA will 
consider all comments received by the closing date and may amend this 
SNPRM because of those comments.
    The FAA will post all comments, without change, to https://www.regulations.gov, including any personal information you provide. 
The FAA will also post a report summarizing each substantive verbal 
contact received about this SNPRM.

Discussion

    The FAA issued an NPRM to amend 14 CFR part 39 by adding an AD that 
would apply to certain The Boeing Company Model 737-600, -700, -700C, -
800, and -900 series airplanes. The NPRM published in the Federal 
Register on October 1, 2019 (84 FR 52047). The NPRM was prompted by 
reports of cracks in the bear strap between certain stations, sometimes 
common to fasteners in the gap cover and emanating from rough sanding 
marks found on the surface of the bear strap. The NPRM proposed to 
require inspections of the fuselage skin and bear strap at the forward 
galley door between certain stations for cracks, and applicable on-
condition actions.

Actions Since the NPRM Was Issued

    Since the FAA issued the NPRM, the FAA has determined that, for 
certain inspections specified in the proposed AD, certain thickness 
callouts for the fuselage skin and bear strap were incorrect. 
Therefore, the FAA has determined the correct thickness callouts must 
be included in those inspections.

Comments

    The FAA gave the public the opportunity to comment on the NPRM. The 
following presents the comments received on the NPRM and the FAA's 
response to each comment.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that accomplishing Supplemental 
Type Certificate (STC) ST00830SE does not affect the actions specified 
in the proposed AD.
    The FAA concurs with the commenter. The FAA has redesignated 
paragraph (c) of the proposed AD as paragraph (c)(1) of this AD and 
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 AD. Therefore, for airplanes on which STC ST00830SE is 
installed, a ``change in product'' alternative method of compliance 
(AMOC) approval request is not necessary to comply with the 
requirements of 14 CFR 39.17.

Request To Include Updated Service Information

    Boeing requested that the FAA revise the NPRM to include a later 
revision of the service information. Boeing pointed out that the skin 
and bear strap thicknesses referenced in Boeing Alert Requirements 
Bulletin 737-53A1383 RB, dated May 9, 2019, were incorrectly specified 
as 0.0710 inches and 0.10 inches respectively, which affects the proper 
calibration of the inspection probe. Boeing stated that the correct 
skin and bear strap thicknesses should be 0.100 inches and 0.090 inches 
respectively. Boeing also mentioned that a new revision to the service 
information that corrects the skin and bear strap thicknesses was being 
coordinated with the FAA.
    The FAA agrees for the reasons provided. Therefore, the FAA has 
included Boeing Alert Requirements Bulletin 737-53A1383 RB, Revision 1, 
dated February 19, 2020, as the appropriate source of service 
information for doing the actions specified in this SNPRM. 
Additionally, the FAA has also included paragraph (i) of this SNPRM to 
allow credit for actions accomplished before the effective date of this 
AD, using Boeing Alert Requirements Bulletin 737-53A1383 RB, dated May 
9, 2019, provided that for airplanes on which Option 2, Condition 4, 
has been done (no external repair and have done the external low 
frequency eddy current (LFEC) inspection of the forward galley door 
bear strap and external high frequency eddy current (HFEC) inspection 
of the fuselage skin for any crack), operators also do the external 
LFEC inspection of the forward galley door bear strap and external HFEC 
inspection of the fuselage skin for any crack identified in accordance 
with Figure 4 of the Accomplishment Instructions of Boeing Alert 
Requirements Bulletin 737-53A1383 RB, Revision 1, dated February 19, 
2020, and do all applicable on-condition actions.

Request for Credit for Actions Accomplished Prior to the Effective Date

    Alaska Airlines (AAL), United Airlines (UAL), and Delta Air Lines 
(DAL) requested that the FAA provide credit for accomplishing the 
actions specified in paragraph (g) of the proposed AD prior to the 
effective date of this AD in accordance with Boeing Alert Requirements 
Bulletin 737-53A1383 RB, dated May 9, 2019 (which was referred to as 
the appropriate source of information for doing the actions required by 
paragraph (g) of the proposed AD).
    The FAA acknowledges the commenter's requests and agrees to 
clarify. As previously stated, the FAA has included Boeing Alert 
Requirements Bulletin 737-53A1383 RB, Revision 1, dated February 19, 
2020, as the appropriate source of service information for doing the 
actions specified in this SNPRM. The FAA has also included paragraph 
(i) of this SNPRM to allow credit for actions accomplished before the 
effective date of this SNPRM, using Boeing Alert Requirements Bulletin 
737-53A1383 RB, dated May 9, 2019, provided, for certain airplanes, 
that certain actions are done.

Request To Exclude a Certain Inspection of Certain Repaired Areas

    DAL requested that the proposed AD be revised to exclude an 
internal surface HFEC inspection in areas that were repaired if the 
repair met certain conditions. DAL noted that the design approval 
holder has specifically recommended that the surface HFEC inspection 
not be required if certain repairs have been accomplished, however, 
those repairs must have been installed after the original issue date of 
Boeing Alert Requirements Bulletin 737-53A1383 RB and must have been 
approved by The Boeing Company Organization Designation Authorization 
(ODA) via FAA Form 8100-9. DAL asked that such repairs be approved as 
AMOCs, regardless of when the repair was installed.
    The FAA agrees to clarify. Paragraph (h)(1) of this AD allows using 
the notes and flag notes in Boeing Alert Requirements Bulletin 737-
53A1383 RB, Revision 1, dated February 19, 2020, as written. This means 
that, for actions done ``after the original issue date of Boeing Alert 
Requirements Bulletin 737-53A1383 RB'' operators are not required to do 
the internal surface HFEC in areas where the repair covers the affected 
inspection zone, provided the repair meets the conditions specified in 
Boeing Alert Requirements Bulletin 737-53A1383 RB, Revision 1, dated 
February 19, 2020. Operators do not need to obtain an AMOC to use this 
provision, provided the repair meets the conditions specified in Boeing 
Alert

[[Page 25350]]

Requirements Bulletin 737-53A1383 RB, Revision 1, dated February 19, 
2020.
    However, the FAA notes that this provision does not extend to 
repairs that were done before the original issue date of Boeing Alert 
Requirements Bulletin 737-53A1383 RB. Under the provisions of paragraph 
(i) of this AD, the FAA will consider requests for approval of repairs 
in this area that affect compliance with this AD and were done before 
the original issue date of Boeing Alert Requirements Bulletin 737-
53A1383 RB if sufficient data are submitted to substantiate that the 
repair would provide an acceptable level of safety. The FAA has not 
changed this SNPRM regarding this issue.

Request for AMOC for Repairs Accomplished Before Service Information 
Publication

    Southwest Airlines (SWA) requested that the FAA include previously 
accomplished repairs for the crack condition identified in Boeing Alert 
Requirements Bulletin 737-53A1383 RB as an approved AMOC, including 
repairs accomplished before the original issue date of Boeing Alert 
Requirements Bulletin 737-53A1383 RB. SWA mentioned that its fleet has 
repaired many crack conditions common to the inspection area specified 
in Boeing Alert Requirements Bulletin 737-53A1383 RB, and that most of 
those repairs were accomplished before Boeing Alert Requirements 
Bulletin 737-53A1383 RB, was released. SWA also pointed out that those 
repairs were approved via FAA Form 8100-9.
    The FAA disagrees with the commenter's request. Note (b) to Tables 
1 and 2 in Boeing Alert Requirements Bulletin 737-53A1383 RB is 
intended to address repairs that were designed as corrective actions to 
the unsafe condition addressed in the service information and this AD, 
are approved by The Boeing Company ODA, and include a follow-on 
inspection program. For this reason, the FAA allows FAA Form 8100-9 for 
approved repairs that meet all criteria specified in note (b) to Tables 
1 and 2 in Boeing Alert Requirements Bulletin 737-53A1383 RB to be 
exempted from the inspections in those repaired areas, but does not 
allow just any FAA-approved repair to be exempted from these required 
inspections. However, under the provisions of paragraph (i) of this AD, 
the FAA will consider requests for approval of certain repairs in this 
area that affect compliance with this AD if sufficient data are 
submitted to substantiate that the repair would provide an acceptable 
level of safety. The FAA has not changed this SNPRM regarding this 
issue.

Request To Clarify Acceptable Previous Repairs

    Qantas Airways LTD (Qantas) requested that the FAA clarify whether 
certain blend repairs would require approval of a new FAA Form 8100-9, 
to reauthorize the existing repairs. Qantas pointed out that the 
criteria for the general visual inspection is ``any repair.'' Qantas 
also mentioned that a blend repair to a small depth may not be 
detectable with a general visual inspection (as specified in Boeing 
Alert Requirements Bulletin 737-53A1383 RB) because the area is shot or 
flap peened after blending.
    The FAA agrees to clarify. Boeing Alert Requirements Bulletin 737-
53A1383 RB specifies certain repairs that do not require additional 
contact with The Boeing Company ODA or the FAA. Those certain repairs 
are specified in note (a) to Table 1 and notes (a) and (b) to Table 2 
of Boeing Alert Requirements Bulletin 737-53A1383 RB as: Fuselage skin 
blend out within the 737-600 structural repair manual (SRM) 53-00-01, 
737-700 SRM 53-00-01, 737-700CONV SRM 53-00-01, 737-700IGW (BBJ) SRM 
53-00-01, 737-800 SRM 53-00-01, 737-800BCF SRM 53-00-01, or 737-900 SRM 
53-00-01 allowable damage. Any existing repair that is not specified in 
that section would require additional contact with The Boeing Company 
ODA or the FAA. The FAA has not changed this SNPRM regarding this 
issue.

Request To Clarify Exception to the Service Information

    Qantas requested that the FAA clarify the intent of the exception 
to the service information specified in paragraph (h)(2) of the 
proposed AD. Qantas mentioned its perception that when Boeing Alert 
Requirements Bulletin 737-53A1383 RB, specifies that ``It is not 
required to contact Boeing,'' that the NPRM then requires the operator 
to contact The Boeing Company ODA.
    The FAA agrees to clarify. Boeing Alert Requirements Bulletin 737-
53A1383 RB specifies certain conditions, where contact with Boeing is 
unnecessary. Whereas, the exception specified in paragraph (h)(2) of 
this SNPRM, states that if Boeing Alert Requirements Bulletin 737-
53A1383 RB, specifies to contact Boeing for repair instructions or for 
alternative inspections, this SNPRM requires doing the repair, or doing 
the alternative inspections and applicable on-condition actions using a 
method approved as an AMOC. The exception in paragraph (h)(2) of this 
AD, therefore, does not affect the statements in Boeing Alert 
Requirements Bulletin 737-53A1383 RB, that specify ``It is not required 
to contact Boeing.'' The FAA has not changed this SNPRM regarding this 
issue.

Request To Allow Alternate Inspection Procedure

    Structural Monitoring Systems PLC (SMS) requested that the FAA 
allow the use of SMS comparative vacuum monitoring (CVM) structural 
monitoring sensors (and a CVM nondestructive testing procedure (NDT)) 
as an alternative to the HFEC inspections of the bear strap. SMS also 
requested that for the CVM NDT procedure, the FAA set a repetitive 
inspection frequency to 18,000 flight cycles to reduce the level of 
repair burden on the operator when a crack is discovered. SMS also 
requested that the CVM structural monitoring sensors be used to 
periodically monitor any crack propagation, using damage tolerant 
assessment data to determine the point of reaching the residual 
strength capability limit, noting that this is a similar practice to 
that used on engines. SMS stated that the structural monitoring sensors 
are less intrusive, require less time to access, and take less time to 
inspect, while providing an equal level of safety to the proposed HFEC 
inspection method. SMS further specified that a CVM NDT inspection 
method can be applied three times (or more) more frequently than the 
proposed HFEC inspection, while still being less time consuming, 
because there is no further disassembly/assembly after initial sensor 
installation. SMS then mentioned that it (SMS) would perform any 
specific evaluation or testing required by the FAA to demonstrate 
standard 90 percent probability of detection with 95 percent confidence 
for the application. SMS mentioned a recent FAA statement acknowledging 
``that an aircraft structure which is subject to damage tolerance 
assessment can be considered safe while continuing to operate with an 
existing [undetected] crack.'' SMS specified the belief that the direct 
quote expresses a philosophy that is supportive of using the CVM 
structural monitoring sensors, and would allow operators to operate the 
aircraft until such time as the residual strength capability is 
reached, using an appropriate inspection interval.
    The FAA disagrees with the request to mandate CVM structural 
monitoring sensors, a repetitive CVM NDT procedure with an 18,000 
flight cycle compliance time, and periodic

[[Page 25351]]

monitoring of crack propagation. SMS did not provide sufficient 
substantiation to show the effectivity of CVM technology for this 
application. Therefore, the FAA cannot specify or allow that technology 
and inspection method as an alternative to those specified in this 
SNPRM. The FAA has not changed this SNPRM regarding this issue. Once 
the final rule is published, any person may request approval of an 
alternative method of compliance (AMOC) under the provisions of 
paragraph (j) of this AD.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 737-53A1383 RB, 
Revision 1, dated February 19, 2020. This service information describes 
procedures for inspecting for cracks of the fuselage skin and bear 
strap at the forward galley door between certain stations, through the 
use of two alternative inspection methods: (1) Internal and external 
general visual inspections and internal surface HFEC inspections, and 
(2) external general visual and external eddy current inspections, and 
applicable on-condition actions. On-condition actions include 
inspections for cracks, HFEC inspections for cracks, LFEC inspections 
for cracks, and repair, depending on the inspection method selected. 
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.

FAA's Determination

    The FAA is proposing this AD because the FAA evaluated all the 
relevant information and determined the unsafe condition described 
previously is likely to exist or develop in other products of the same 
type design. Certain revisions to the service information described 
above expand the scope of the NPRM. As a result, the FAA has determined 
that it is necessary to reopen the comment period to provide additional 
opportunity for the public to comment on this SNPRM.

Proposed Requirements of This SNPRM

    This SNPRM would require accomplishing the actions specified in the 
service information described previously. This proposed AD would also 
allow credit for airplanes that have done Option 2, Condition 4, as 
specified in Boeing Alert Requirements Bulletin 737-53A1383 RB, dated 
May 9, 2019, provided that those airplanes do additional inspections. 
For information on the procedures and compliance times, see this 
service information at https://www.regulations.gov by searching for and 
locating Docket No. FAA-2019-0705.

Costs of Compliance

    The FAA estimates that this proposed AD affects 752 airplanes of 
U.S. registry. The FAA estimates the following costs to comply with 
this proposed AD:

                                 Estimated Costs for Required Actions: Option 1
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Internal general visual            11 work-hours x $85              $0  $935...............  $703,120.
 inspection.                        per hour = $935.
External general visual            1 work-hour x $85                 0  85.................  63,920.
 inspection.                        per hour = $85.
Internal Surface HFEC inspections  3 work-hours x $85                0  255 per inspection   191,760 per
                                    per hour = $255                      cycle.               inspection cycle.
                                    per inspection
                                    cycle.
----------------------------------------------------------------------------------------------------------------

                                 Estimated Costs for Required Actions: Option 2
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
External general visual            1 work-hour x $85                $0  $85................  $63,920.
 inspection.                        per hour = $85.
External LFEC and HFEC             18 work-hours x $85               0  1,530 per            1,150,560 per
 inspections.                       per hour = $1,530                    inspection cycle.    inspection cycle.
                                    per inspection
                                    cycle.
----------------------------------------------------------------------------------------------------------------

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

    The FAA determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 this proposed 
regulation:
    (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.

[[Page 25352]]

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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):

The Boeing Company: Docket No. FAA-2019-0705; Product Identifier 
2019-NM-098-AD.

(a) Comments Due Date

    The FAA must receive comments by June 15, 2020.

(b) Affected ADs

    None.

(c) Applicability

    (1) This AD applies to The Boeing Company Model 737-600, -700, -
700C, -800, and -900 series airplanes, certificated in any category, 
as identified in Boeing Alert Requirements Bulletin 737-53A1383 RB, 
Revision 1, dated February 19, 2020.
    (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 is not necessary to comply with 
the requirements of 14 CFR 39.17.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by reports of cracks in the bear strap from 
station (STA) 290 to STA 296, and between S-8R and S-9R, sometimes 
common to fasteners in the gap cover and emanating from rough 
sanding marks found on the surface of the bear strap. The FAA is 
issuing this AD to address cracking of the bear strap, which could 
result in severing of the bear strap, possibly leading to 
uncontrolled decompression of the airplane and loss of structural 
integrity of the airplane.

(f) Compliance

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

(g) Required Actions

    Except as specified by paragraph (h) of this AD: At the 
applicable times specified in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin 737-53A1383 RB, Revision 1, dated 
February 19, 2020, do all applicable actions identified in, and in 
accordance with, the Accomplishment Instructions of Boeing Alert 
Requirements Bulletin 737-53A1383 RB, Revision 1, dated February 19, 
2020.

    Note 1 to paragraph (g):  Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
737-53A1383, Revision 1, dated February 19, 2020, which is referred 
to in Boeing Alert Requirements Bulletin 737-53A1383 RB, Revision 1, 
dated February 19, 2020.

(h) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Requirements Bulletin 737-53A1383 RB, 
Revision 1, dated February 19, 2020, uses the phrase ``the original 
issue date of Requirements Bulletin 737-53A1383 RB,'' this AD 
requires using ``the effective date of this AD,'' except where 
Boeing Alert Requirements Bulletin 737-53A1383 RB, Revision 1, dated 
February 19, 2020, uses the phrase ``the original issue date of 
Requirements Bulletin 737-53A1383 RB'' in a note or flag note.
    (2) Where Boeing Alert Requirements Bulletin 737-53A1383 RB, 
Revision 1, dated February 19, 2020, specifies contacting Boeing for 
repair instructions or for alternative inspections: This AD requires 
doing the repair, or doing the alternative inspections and 
applicable on-condition actions, using a method approved in 
accordance with the procedures specified in paragraph (j) 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 Alert Requirements Bulletin 
737-53A1383 RB, dated May 9, 2019, except for airplanes on which 
Option 2, Condition 4 has been done. For airplanes on which Option 
2, Condition 4, has been done, credit is given provided operators do 
the external low frequency eddy current (LFEC) inspection of the 
forward galley door bear strap and external high frequency eddy 
current (HFEC) inspection of the fuselage skin for any crack in 
accordance with Figure 4 of the Accomplishment Instructions of 
Boeing Alert Requirements Bulletin 737-53A1383 RB, Revision 1, dated 
February 19, 2020. The compliance time for accomplishing these 
actions is at the later of the time specified in paragraphs (i)(1) 
and (2) of this AD. Do all applicable on-condition actions 
identified in, and in accordance with, the Accomplishment 
Instructions of Boeing Alert Requirements Bulletin 737-53A1383 RB, 
Revision 1, dated February 19, 2020, at the applicable times 
specified in the ``Compliance'' paragraph of Boeing Alert 
Requirements Bulletin 737-53A1383 RB, Revision 1, dated February 19, 
2020.
    (1) Before 15,000 total flight cycles.
    (2) Within 6,000 flight cycles after the effective date 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)(1) of this AD. Information may be 
emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (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

    (1) 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: michael.bumbaugh@faa.gov.
    (2) 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; phone: 562-797-1717; internet: https://www.myboeingfleet.com. 
You may view this referenced 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.

    Issued on April 20, 2020.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2020-09114 Filed 4-30-20; 8:45 am]
 BILLING CODE 4910-13-P