Airworthiness Directives; The Boeing Company Airplanes

[Federal Register Volume 84, Number 90 (Thursday, May 9, 2019)]
[Rules and Regulations]
[Pages 20248-20252]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-09522]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0900; Product Identifier 2018-NM-101-AD; Amendment 
39-19623; AD 2019-08-02]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 
series airplanes. This AD was prompted by reports of cracking in the 
frame web, frame integral inboard chord, and fail-safe chord on 
multiple airplanes in multiple locations between stringers S-10 and S-
17 above the passenger floor, in addition to an evaluation by the 
design approval holder (DAH) indicating that certain fuselage frame 
splices are subject to widespread fatigue damage (WFD). This AD 
requires repetitive inspections of certain fuselage upper frames, side 
frames, fail-safe chords, inboard chords, frame webs, and stringers; an 
inspection for open tooling holes and the presence of repairs in 
certain inspection zones; and applicable on-condition actions. We are 
issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective June 13, 2019.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of June 13, 
2019.

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

[[Page 20249]]

material at the FAA, call 206-231-3195. It is also available on the 
internet at http://www.regulations.gov by searching for and locating 
Docket No. FAA-2018-0900.

Examining the AD Docket

    You may examine the AD docket on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2018-
0900; 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 (phone: 800-647-
5527) 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: George Garrido, Aerospace Engineer, 
Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount 
Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5232; fax: 562-627-
5210; email: [email protected].

SUPPLEMENTARY INFORMATION: 

Discussion

    We 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 737-100, -200, -200C, -300, -400, and -500 series airplanes. The 
NPRM published in the Federal Register on October 16, 2018 (83 FR 
52173). The NPRM was prompted by reports of cracking in the frame web, 
frame integral inboard chord, and fail-safe chord on multiple airplanes 
in multiple locations between stringers S-10 and S-17 above the 
passenger floor, in addition to an evaluation by the DAH indicating 
that certain fuselage frame splices are subject to WFD. The NPRM 
proposed to require repetitive inspections of certain fuselage upper 
frames, side frames, fail-safe chords, inboard chords, frame webs, and 
stringers; an inspection for open tooling holes and the presence of 
repairs in certain inspection zones; and applicable on-condition 
actions.
    We are issuing this AD to address cracks in these locations, which 
could grow large enough to sever frames. Continued operation with 
multiple adjacent severed frames or a combination of a severed frame 
adjacent to fuselage skin cracks in chem-milled pockets could result in 
a loss of structural integrity or uncontrolled decompression.

Comments

    We 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.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that accomplishing the Supplemental 
Type Certificate (STC) ST01219SE does not affect the actions specified 
in the NPRM.
    We concur with the commenter. We have 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 ST01219SE does not 
affect the ability to accomplish the actions required by this AD. 
Therefore, for airplanes on which STC ST01219SE 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 for Clarification About Frame Replacement

    Commenter Mark Bowen observed that ``if a crack or non SRM/Boeing 
repair'' is found as part of inspections accomplished under Boeing 
Alert Service Bulletin 737-53A1360, the only action given in the 
proposed AD is to contact Boeing for repair or alternative inspections. 
He asked whether frame replacement could be considered an alternative 
option to contacting Boeing for a repair or alternative inspections.
    We partially agree with the commenter's request. Frame replacement 
that removes the cracked or repaired structure may be an option to 
repair or alternative inspections, provided the replacement can be 
shown to adequately address the unsafe condition. However, we note that 
the commenter did not provide sufficient documentation to show that, in 
regard to the unsafe condition identified in this AD, a frame 
replacement would adequately address the unsafe condition. In addition, 
the commenter did not provide details on a proposed method of 
compliance for accomplishing the proposed frame replacement and post-
replacement inspections, nor any evidence of support for the proposal 
from the Boeing Commercial Airplanes Organization Designation 
Authorization (ODA). Operators may apply for an alternative method of 
compliance in accordance with paragraph (k) of this AD, provided they 
can show that frame replacement adequately addresses the unsafe 
condition. We have not changed this AD in this regard.

Request To Remove Model 737-100 Series Airplanes From a Sentence in the 
Discussion Paragraph of the NPRM

    Boeing has requested that we remove Model 737-100 airplanes from 
the sentence ``We have received a report indicating that cracking is 
being found . . . on multiple Model 737-100, -200, -200C, -300, -400, 
and -500 series airplanes'' in the Discussion paragraph of the NPRM. 
The commenter asserted that they have not received reports of frame 
cracking on that airplane model.
    We acknowledge that cracking has not been found on Model 737-100 
series airplanes. However, that sentence is not restated in this final 
rule, so we have not revised it in this regard.

Request To Change Location of Unsafe Condition

    Boeing requested that we change the location of the unsafe 
condition from ``below the passenger floor'' to ``between stringers S-
10 and S-17 above the passenger floor,'' because the proposed AD and 
the referenced service information only address frame cracking above 
the passenger floor.
    We agree with the commenter's request and have changed this AD 
accordingly.

Request To Coordinate Proposed Compliance Times and Actions With STC 
Holder

    Boeing observed that the proposed AD would include the application 
of actions specific to the Model 737-200C airplanes (Group 3) to 
certain Model 737CL airplanes that have been modified to a non-Boeing 
STC cargo configuration. Boeing recommended the FAA coordinate the 
proposed compliance times and actions with the STC holder.
    We partially agree with Boeing's comments. We agree with their 
observation regarding Model 737CL airplanes. However, we do not agree 
to coordinate compliance times and actions with the STC holders because 
this would unnecessarily delay issuance of the final rule, and the 
times and actions are similar for airplanes converted to a freighter. 
If an operator of airplanes modified with a non-Boeing freighter 
conversion STC would like to accomplish the AD at different times or 
with different actions, they can request an AMOC in accordance with 
paragraph (k) of this AD. No changes to this AD are necessary.

[[Page 20250]]

Clarification of Exception Language

    We included a standard service bulletin exception in paragraph 
(i)(1) of the proposed AD for determining compliance with this AD. 
However, we did not intend the exception to apply to the text that 
describes exceptions to inspection areas found in notes or flag notes 
of Boeing Alert Service Bulletin 737-53A1360, dated June 21, 2018. 
Therefore, we have revised paragraph (i)(1) of this AD accordingly.

Conclusion

    We 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. We have determined that these minor changes:
    <bullet> Are consistent with the intent that was proposed in the 
NPRM for addressing the unsafe condition; and
    <bullet> Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    We 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

    We reviewed Boeing Alert Service Bulletin 737-53A1360, dated June 
21, 2018. This service information describes procedures for repetitive 
inspections of certain fuselage upper frames, side frames, fail-safe 
chords, inboard chords, frame webs, and stringers; an inspection for 
open tooling holes and the presence of repairs in certain inspection 
zones; and applicable on-condition actions. 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

    We estimate that this AD affects 262 airplanes of U.S. registry. We 
estimate the following costs to comply with this AD:

                                      Estimated Costs for Required Actions
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                   Labor cost          Parts cost       Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Inspections.....................  Up to 243 work-     None..............  Up to $20,655 per   Up to $5,411,610
                                   hours x $85 per                         inspection cycle.   per inspection
                                   hour = $20,655                                              cycle.
                                   per inspection
                                   cycle.
----------------------------------------------------------------------------------------------------------------

    We have received no definitive data that would enable us to provide 
cost estimates for the on-condition actions 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.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.
    This AD is issued in accordance with authority delegated by the 
Executive Director, Aircraft Certification Service, as authorized by 
FAA Order 8000.51C. In accordance with that order, issuance of ADs is 
normally a function of the Compliance and Airworthiness Division, but 
during this transition period, the Executive Director has delegated the 
authority to issue ADs applicable to transport category airplanes and 
associated appliances to the Director of the System Oversight Division.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:


    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

2019-08-02 The Boeing Company: Amendment 39-19623 ; Docket No. FAA-
2018-0900; Product Identifier 2018-NM-101-AD.

(a) Effective Date

    This AD is effective June 13, 2019.

(b) Affected ADs

    None.

(c) Applicability

    (1) This AD applies to The Boeing Company Model 737-100, -200, -
200C, -300, -400, and -500 series airplanes, certificated in any 
category, as identified in Boeing Alert Service Bulletin 737-
53A1360, dated June 21, 2018.
    (2) Installation of Supplemental Type Certificate (STC) 
ST01219SE does not affect the ability to accomplish the actions 
required by this AD. Therefore, for airplanes on which STC ST01219SE 
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.

[[Page 20251]]

(e) Unsafe Condition

    This AD was prompted by reports of cracking in the frame web, 
frame integral inboard chord, and fail-safe chord on multiple 
airplanes in multiple locations between stringers S-10 and S-17 
above the passenger floor, in addition to an evaluation by the 
design approval holder (DAH) indicating that the fuselage frame 
splices from station (STA) 380 to STA 520 and STA 727A to STA 907 
between stringers S-13 and S-14 are subject to widespread fatigue 
damage (WFD). We are issuing this AD to address cracks in these 
locations, which could grow large enough to sever frames. Continued 
operation with multiple adjacent severed frames or a combination of 
a severed frame adjacent to fuselage skin cracks in chem-milled 
pockets could result in a loss of structural integrity or 
uncontrolled decompression.

(f) Compliance

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

(g) Actions for Group 1

    For airplanes identified as Group 1 in Boeing Alert Service 
Bulletin 737-53A1360, dated June 21, 2018: Within 120 days after the 
effective date of this AD, inspect the airplane and do all 
applicable on-condition actions using a method approved in 
accordance with the procedures specified in paragraph (k) of this 
AD.

(h) Inspection for Groups 2 through 9

    For airplanes identified as Groups 2 through 9 in Boeing Alert 
Service Bulletin 737-53A1360, dated June 21, 2018, except as 
specified in paragraph (i) of this AD: At the applicable times 
specified in paragraph 1.E., ``Compliance,'' of Boeing Alert Service 
Bulletin 737-53A1360, dated June 21, 2018, do all applicable actions 
identified as ``RC'' (required for compliance) in, and in accordance 
with, the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1360, dated June 21, 2018.

(i) Exceptions to Service Information Specifications

    (1) For purposes of determining compliance with the requirements 
of this AD: Where Boeing Alert Service Bulletin 737-53A1360, dated 
June 21, 2018, uses the phrase ``the original issue date of this 
service bulletin,'' this AD requires using ``the effective date of 
this AD,'' except where Boeing Alert Service Bulletin 737-53A1360, 
dated June 21, 2018, uses the phrase ``the original issue date of 
this service bulletin'' in a note or flag note.
    (2) Where Boeing Alert Service Bulletin 737-53A1360, dated June 
21, 2018, specifies contacting Boeing for repair instructions: This 
AD requires repair and applicable on-condition actions using a 
method approved in accordance with the procedures specified in 
paragraph (k) of this AD.
    (3) Where Boeing Alert Service Bulletin 737-53A1360, dated June 
21, 2018, specifies contacting Boeing for alternative inspections: 
This AD requires alternative inspections using a method approved in 
accordance with the procedures specified in paragraph (k) of this 
AD.
    (4) For airplanes identified as Group 2 and Groups 4 through 9 
in Boeing Alert Service Bulletin 737-53A1360, dated June 21, 2018, 
that have been modified to a cargo configuration: In addition to the 
actions required by paragraph (h) of this AD, the actions specified 
in Table 9, ``Inspection of the Fuselage Frame Integral Inboard 
Chord and Web from STA 360 to STA 400, Right Side,'' of Boeing Alert 
Service Bulletin 737-53A1360, dated June 21, 2018, must be done by 
doing all applicable actions identified as ``RC'' (required for 
compliance) in, and in accordance with, the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1360, dated 
June 21, 2018, at the applicable compliance times specified in Table 
9, ``Inspection of the Fuselage Frame Integral Inboard Chord and Web 
from STA 360 to STA 400, Right Side,'' of Boeing Alert Service 
Bulletin 737-53A1360, dated June 21, 2018, except as specified in 
paragraphs (i)(1) and (i)(2) of this AD.

(j) Terminating Actions for Repetitive Inspections

    (1) Accomplishment of a preventative modification specified in 
Part 7 of the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1360, dated June 21, 2018, at a tooling hole 
location, terminates the repetitive inspections specified in Part 6 
of the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-53A1360, dated June 21, 2018, that are required by paragraph (h) 
of this AD, for that modified tooling hole location only.
    (2) Accomplishment of a high frequency eddy current inspection 
specified in Part 9 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 737-53A1360, dated June 21, 2018, terminates 
the repetitive inspections specified in Part 2 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1360, dated 
June 21, 2018, that are required by paragraph (h) of this AD, at the 
uppermost frame splice fastener location only.

(k) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles 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 Commercial Airplanes Organization 
Designation Authorization (ODA) that has been authorized by the 
Manager, Los Angeles 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.
    (4) Except as required by paragraph (i) of this AD: For service 
information that contains steps that are labeled as RC, the 
provisions of paragraphs (k)(4)(i) and (k)(4)(ii) of this AD apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with the AD. If a step or substep is labeled ``RC Exempt,'' then the 
RC requirement is removed from that step or substep. An AMOC is 
required for any deviations to RC steps, including substeps and 
identified figures.
    (ii) Steps not labeled as RC 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 RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(l) Related Information

    For more information about this AD, contact George Garrido, 
Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
5232; fax: 562-627-5210; 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 Alert Service Bulletin 737-53A1360, dated June 21, 
2018.
    (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, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.


[[Page 20252]]


    Issued in Des Moines, Washington, on April 25, 2019.
Michael Kaszycki,
Acting Director, System Oversight Division, Aircraft Certification 
Service.
[FR Doc. 2019-09522 Filed 5-8-19; 8:45 am]
 BILLING CODE 4910-13-P

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