Airworthiness Directives; The Boeing Company Airplanes

[Federal Register Volume 84, Number 158 (Thursday, August 15, 2019)]
[Rules and Regulations]
[Pages 41614-41617]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-17501]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0023; Product Identifier 2018-NM-145-AD; Amendment 
39-19700; AD 2019-15-07]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain The Boeing Company Model 737-100, 737-200, 737-200C, 737-300, 
737-400, and 737-500 series airplanes. This AD was prompted by reports 
of cracks in the frames below the passenger floor. This AD requires 
repetitive inspections for cracking of the fuselage lower lobe frames, 
and applicable on-condition actions. This AD also provides an optional 
terminating action for certain repetitive inspections. The FAA is 
issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective September 19, 2019.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of September 
19, 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 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-2019-
0023.

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-2019-
0023; 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: 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

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain The Boeing 
Company Model 737-100, 737-200, 737-200C, 737-300, 737-400, and 737-500 
series airplanes. The NPRM published in the Federal Register on March 
1, 2019 (84 FR 6984). The NPRM was prompted by reports of cracks in the 
frames below the passenger floor. The NPRM proposed to require 
repetitive inspections for cracking of the fuselage lower lobe frames, 
and applicable on-condition actions. The NPRM also provided an optional 
terminating action for certain repetitive inspections.
    The FAA is issuing this AD to address cracks that could propagate 
until the frame severs. Continued operation of the airplane with 
multiple adjacent severed frames, or the combination of a severed frame 
adjacent to fuselage skin chem-mill cracks, could result in an 
uncontrolled decompression and loss of structural integrity of the 
airplane.

[[Page 41615]]

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

    Adam Furman, Eric Jacobsen, and Riya Shah stated support for the 
NPRM.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that accomplishing Supplemental 
Type Certificate (STC) ST01219SE does not affect compliance with the 
proposed actions.
    The FAA concurs with the commenter. The agency 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 
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 requirement 
of 14 CFR 39.17.

Request To Revise the Applicability

    Boeing requested that the applicability of the proposed AD be 
changed from ``all The Boeing Company Model 737-100, 737-200, 737-200C, 
737-300, 737-400, and 737-500 series airplanes'' to ``The Boeing 
Company Model 737-100, 737-200, 737-200C, 737-300, 737-400, and 737-500 
series airplanes as identified in Boeing Alert Service Bulletin 737-
53A1362, dated September 20, 2018.'' The commenter stated that this is 
more accurate because not all line numbers for the identified Model 737 
airplanes are affected.
    The FAA agrees with the commenter's request. Paragraph 1.A.1. of 
Boeing Alert Service Bulletin 737-53A1362, dated September 20, 2018, 
identifies the affected Model 737 airplanes and does not include all of 
the airplane line numbers. In addition, the affected parts are not 
rotable, so once a part is removed from an affected airplane it would 
not be installed on another airplane including airplanes outside the 
line-number range in the service bulletin. The FAA has changed SUMMARY 
and the Discussion section in SUPPLEMENTARY INFORMATION of this final 
rule to ``certain The Boeing Company Model 737-100, 737-200, 737-200C, 
737-300, 737-400, and 737-500 series airplanes.'' The FAA has also 
changed paragraph (c)(1) of this AD (paragraph (c) of the proposed AD) 
to refer to The Boeing Company Model 737-100, 737-200, 737-200C, 737-
300, 737-400, and 737-500 series airplanes, certificated in any 
category, as identified in Boeing Alert Service Bulletin 737-53A1362, 
dated September 20, 2018.

Request To Clarify Terminology Regarding Frames

    Boeing requested that the term ``frame webs'' be changed to 
``frames'' where the location of the cracking was described, throughout 
the NPRM. The commenter stated that this is more accurate because 
cracks were found in the frame chords as well as the frame webs, and 
the reference should be to frames as a whole.
    The FAA agrees with the commenter's request for the reasons 
provided by the commenter. The FAA has revised SUMMARY and the 
Discussion section in SUPPLEMENTARY INFORMATION of this final rule and 
paragraph (e) of this AD to refer to cracks in ``frames'' instead of 
``frame webs.''

Request To Clarify Terminology Regarding Chem-Mill Cracks

    Boeing requested that the term ``fuselage skin chem-milled cracks'' 
be changed to ``fuselage skin chem-mill cracks'' throughout the NPRM. 
The commenter stated that this more accurately describes the condition.
    The FAA agrees with the commenter's request for the reason provided 
by the commenter. The agency has revised the Discussion section of this 
final rule and paragraph (e) of this AD to refer to ``fuselage skin 
chem-mill'' cracks instead of ``fuselage skin chem-milled'' cracks.

Request To Reduce the Compliance Time

    Katie Draus, Shawn McPartland, and an anonymous commenter requested 
that the compliance time in the proposed AD be reduced. The commenters 
recommended that the proposed AD be put into effect immediately because 
of the seriousness of the unsafe condition.
    The FAA acknowledges the commenters' concerns, but does not agree 
to reduce the compliance time of this final rule. In developing an 
appropriate compliance time for this action, the agency considered the 
urgency associated with the unsafe condition, the availability of 
replacement parts, and the practical aspect of accomplishing the 
required modification within a period of time that corresponds to the 
normal scheduled maintenance for most affected operators. The FAA has 
not revised this AD in regard to this issue.

Request To Revise Exceptions to Service Information Specifications

    Boeing requested that paragraph (j)(1) of the proposed AD be 
revised so that instead of mandating the use of ``the effective date of 
this AD,'' it would state that the ``effective date of this AD'' can be 
substituted for the original issue date of Boeing Alert Service 
Bulletin 737-53A1362, dated September 20, 2018. Boeing stated that 
mandating ``the effective date of this AD'' for determining compliance 
might discourage operators from doing the actions in the service 
information prior to the effective date of the AD.
    Boeing also noted that some of the work instructions in Boeing 
Alert Service Bulletin 737-53A1362, dated September 20, 2018, contain 
notes that provide relief from inspection requirements if a Boeing 
repair was accomplished for the crack condition after the original 
issue date of the service bulletin. Boeing pointed out that because 
these notes also contain the phrase ``the original issue date of this 
service bulletin,'' requiring the use of ``the effective date of this 
AD'' might lead operators to think that an AMOC approval would be 
needed for relief from inspections on repairs accomplished after the 
service bulletin release but prior to publication of the final rule. 
Boeing suggested that changing the wording would clarify that an AMOC 
approval is not needed.
    The FAA acknowledges the commenter's concern regarding this issue. 
The agency disagrees that the wording would discourage operators from 
accomplishing the actions in Boeing Alert Service Bulletin 737-53A1362, 
dated September 20, 2018, prior to the effective date of this AD 
because paragraph (f) of this AD provides credit for the actions done 
before the effective date of this AD.
    In response to the commenter's concern regarding the use of ``the 
effective date of this AD'' instead of ``the original issue date of 
this service bulletin'' in the notes of Boeing Alert Service Bulletin 
737-53A1362, dated September 20, 2018, the FAA has revised paragraph 
(j)(1) of this AD to state that ``Where BASB 737-53A1362 uses the 
phrase `the original issue date of this service bulletin,' this AD 
requires using `the effective date of this AD,' except where BASB 737-
53A1362 uses the phrase `the original issue date of this service 
bulletin' in a note or flag note.''

[[Page 41616]]

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 agency has 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.
    The FAA has also determined that these changes will not increase 
the economic burden on any operator or increase the scope of this final 
rule.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Service Bulletin 737-53A1362, dated 
September 20, 2018. The service information describes procedures for 
repetitive inspections for cracking of the fuselage lower lobe frames, 
applicable on-condition actions, and an optional modification of the 
tooling holes and insulation attachment holes. On-condition actions 
include repetitive inspections for cracking of the lower lobe frames, 
repair, and repetitive post-repair inspections for cracking.
    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 262 airplanes of U.S. 
registry. The agency estimates 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
----------------------------------------------------------------------------------------------------------------
Inspection.......................  Up to 56 work-hours              $0  Up to $4,760 per     Up to $1,247,120
                                    x $85 per hour =                     inspection cycle.    per inspection
                                    $4,760 per                                                cycle.
                                    inspection cycle.
----------------------------------------------------------------------------------------------------------------


                                      Estimated Costs for Optional Actions
----------------------------------------------------------------------------------------------------------------
                 Action                           Labor cost            Parts cost         Cost per product
----------------------------------------------------------------------------------------------------------------
Modification............................  1 work-hour x $85 per hour             [*]  $85 per hole.
                                           = $85 per hole.
----------------------------------------------------------------------------------------------------------------
* Parts and materials (e.g., rivets, bolts, collars, primer, adhesive) are supplied by the operator.

    The FAA has received no definitive data that would enable the 
agency 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.
    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.
    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) 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):

2019-15-07 The Boeing Company: Amendment 39-19700; Docket No. FAA-
2019-0023; Product Identifier 2018-NM-145-AD.

(a) Effective Date

    This AD is effective September 19, 2019.

(b) Affected ADs

    None.

(c) Applicability

    (1) This AD applies to The Boeing Company Model 737-100, 737-
200, 737-200C, 737-300, 737-400, and 737-500 series airplanes, 
certificated in any category, as identified in Boeing Alert Service 
Bulletin 737-53A1362, dated September 20, 2018 (``BASB 737-
53A1362'').
    (2) Installation of Supplemental Type Certificate (STC) 
ST01219SE does not affect

[[Page 41617]]

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.

(e) Unsafe Condition

    This AD was prompted by reports of cracks in the frames below 
the passenger floor. The FAA is issuing this AD to address cracks 
that could propagate until the frame severs. Continued operation of 
the airplane with multiple adjacent severed frames, or the 
combination of a severed frame adjacent to fuselage skin chem-mill 
cracks, could result in an uncontrolled decompression 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 for Group 1 Airplanes

    For airplanes identified as Group 1 in BASB 737-53A1362: Within 
120 days after the effective date of this AD, accomplish actions to 
correct the unsafe condition (e.g., inspections and on-condition 
actions) using a method approved in accordance with the procedures 
specified in paragraph (k) of this AD.

(h) Required Actions for Group 2 Through 20 Airplanes

    For airplanes identified as Group 2 through 20 in BASB 737-
53A1362: Except as specified in paragraph (i) of this AD, at the 
applicable times specified in paragraph 1.E., ``Compliance,'' of 
BASB 737-53A1362, do all applicable actions identified as ``RC'' 
(required for compliance) in, and in accordance with, the 
Accomplishment Instructions of BASB 737-53A1362.

(i) Optional Terminating Action for Certain Repetitive Inspections

    For airplanes identified as Group 2 through 20 in BASB 737-
53A1362, accomplishment of part 13, ``Preventive Modification of the 
Frame Web Tooling Hole and Insulation Attachment Hole in the Section 
46 Lower Lobe Frame,'' in accordance with the Accomplishment 
Instructions of BASB 737-53A1362, terminates the repetitive open 
hole high frequency eddy current inspections required by paragraph 
(h) of this AD, for the modified tooling hole or insulation 
attachment hole location only.

(j) Exceptions to Service Information Specifications

    (1) For purposes of determining compliance with the requirements 
of this AD: Where BASB 737-53A1362 uses the phrase ``the original 
issue date of this service bulletin,'' this AD requires using ``the 
effective date of this AD,'' except where BASB 737-53A1362 uses the 
phrase ``the original issue date of this service bulletin'' in a 
note or flag note.
    (2) Where BASB 737-53A1362 specifies contacting Boeing for 
repair instructions or 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 (k) of this 
AD.

(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 Company 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 (j)(2) of this AD: For 
service information that contains steps that are labeled as Required 
for Compliance (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 737-53A1362, dated September 
20, 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.

    Issued in Des Moines, Washington, on July 30, 2019.
Michael Kaszycki,
Acting Director, System Oversight Division, Aircraft Certification 
Service.
[FR Doc. 2019-17501 Filed 8-14-19; 8:45 am]
 BILLING CODE 4910-13-P

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