[Federal Register Volume 85, Number 29 (Wednesday, February 12, 2020)]
[Rules and Regulations]
[Pages 7865-7868]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-02719]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0670; Product Identifier 2019-NM-104-AD; Amendment 
39-19830; AD 2020-02-16]
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 737-200, -200C, -300, -400, and -500 
series airplanes. This AD was prompted by an evaluation by the design 
approval holder (DAH) indicating that the lower skin of the fuselage 
skin lap splices along the lower fastener row of a certain stringer lap 
splice on certain body station skin panels may be subject to widespread 
fatigue damage (WFD). This AD requires inspections of the lower skin of 
the fuselage skin lap splices along the lower fastener row of a certain 
stringer lap splice on certain body station skin panels and applicable 
on-condition actions. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective March 18, 2020.
    The Director of the Federal Register approved the incorporation by 
reference

[[Page 7866]]

of a certain publication listed in this AD as of March 18, 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; phone: 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-
0670.

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-
0670; 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: James Guo, Aerospace Engineer, 
Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount 
Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5357; fax: 562-627-
5210; email: james.guo@faa.gov.

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 737-200, -200C, -300, -400, and -500 series airplanes. 
The NPRM published in the Federal Register on September 4, 2019 (84 FR 
46496). The NPRM was prompted by a report that an operator of a Model 
737-300 airplane discovered a crack in the skin at a chem-milled step 
at body station (STA) 727B+10, just above stringer (S)-14R. The 
airplane had accumulated 88,805 flight hours and 65,804 flight cycles 
at the time the crack was found. Upon further inspection in the local 
area using high frequency eddy current (HFEC) hole probe inspection, 
multiple fastener hole cracks were found in the S-14 lap splice lower 
row in the lower skin between STA 727A and STA 727E. The lower skin at 
S-14 is structure that may be susceptible to WFD and may also have 
scratches that can propagate into cracks. The scratch cracks may 
interact with fatigue cracking. The NPRM proposed to require 
inspections of the lower skin of the fuselage skin lap splices along 
the lower fastener row of a certain stringer lap splice on certain body 
station skin panels and applicable on-condition actions.
    The FAA is issuing this AD to address scratch cracks and fatigue 
cracking, which may interact and could result in rapid decompression 
and loss of structural integrity of the airplane.

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

    Priscilla Suarez expressed support for the NPRM, as well as support 
for additional safety inspections, and stricter regulations that 
increase safety.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that accomplishing Supplemental 
Type Certificate (STC) ST01219SE 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 
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 To Specify That the Airplane May Be Subject to the Unsafe 
Condition

    Boeing requested that the FAA revise the SUMMARY, Discussion 
section, and paragraph (e) in the regulatory text of the NPRM to 
specify that the lap splice on certain body station skin panels may be 
subject to widespread fatigue damage WFD. Boeing pointed out that the 
change would maintain consistency with the wording used in the service 
information. Boeing also mentioned that WFD has not been specifically 
demonstrated in the subject areas.
    The FAA agrees for the reasons provided and has revised this AD 
accordingly.

Request To Revise the Unsafe Condition

    Boeing requested that the FAA revise the unsafe condition statement 
throughout the NPRM to specify only that it could result in rapid 
decompression, and remove ``. . . or loss of structural integrity of 
the airplane,'' as an additional consequent result. Boeing pointed out 
that the change would maintain consistency with the wording in the 
service information.
    The FAA partially agrees. The FAA agrees that the wording of the 
unsafe condition could be confusing and that clarification is 
necessary. Therefore, the FAA has changed the unsafe condition 
statement to specify that this AD addresses ``. . . scratch cracks and 
fatigue cracking, which may interact and could result in rapid 
decompression and loss of structural integrity of the airplane.''

Request To Remove Language Regarding Fatigue Damage

    Boeing requested that the FAA remove language regarding fatigue 
damage and multiple-site damage (MSD) from the Discussion section of 
the NPRM. Boeing stated that the information is confusing, provides no 
additional understanding of the issues, and that other AD's related to 
lap splice scratch cracking and MSD do not include the same 
information. Boeing argued that the remaining portions of the 
discussion are sufficient with the intent of the NPRM.
    The FAA does not agree, because the language identified by Boeing 
is not carried forward into the final rule. The FAA acknowledges that 
the language regarding fatigue damage and MSD is not present in all ADs 
related to lap splice cracking; however, this specific language is 
present in other ADs that are related to MSD. This wording helps define 
the terms, provides general explanation of the issue, and has not been 
demonstrated as confusing. The FAA has not changed this AD in this 
regard.

Request for Clarification of the Terminating Action

    Boeing requested that the FAA revise paragraph (i) of the proposed 
AD to clarify if the proposed terminating action is applicable to ``the 
corresponding locations'' or ``the inspections'' in the corresponding 
locations. Boeing pointed out that rearranging the statement would make 
it grammatically clear whether actions or

[[Page 7867]]

locations are being terminated. Otherwise, Boeing pointed out that the 
statement could be misread to interpret it to mean terminating the 
locations required by the NPRM.
    The FAA agrees for the reasons provided and has revised paragraph 
(i) of this AD accordingly.

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.

Related Service Information Under 1 CFR Part 51

    The FAA has reviewed Boeing Alert Requirements Bulletin 737-53A1382 
RB, dated May 6, 2019. This service information describes procedures 
for detailed inspections for previous repairs, and repetitive dual 
frequency eddy current (DFEC) inspections for cracks of the lower skin 
of the fuselage skin lap splices along the lower fastener row of the S-
14 lap splice at specified locations on the STA 727 to STA 908 skin 
panel in areas not inspected as specified in other service bulletins, 
and applicable on-condition actions. On-condition actions include open 
hole HFEC inspections for cracks, and repair. 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 158 airplanes of U.S. 
registry. The FAA 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
----------------------------------------------------------------------------------------------------------------
DFEC Inspections of S-14 Lap       18 work-hours x $85              $0  $1,530 per           $241,740 per
 Splices.                           per hour = $1,530                    inspection cycle.    inspection cycle.
                                    per inspection
                                    cycle.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary on-
condition inspections that would be required. The FAA has no way of 
determining the number of aircraft that might need these on-condition 
actions:

                                     Estimated Costs of On-Condition Actions
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                                  Labor cost                                       Parts cost        product
----------------------------------------------------------------------------------------------------------------
97 work-hours x $85 per hour = $8,245.........................................              $0           $8,245
----------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data that would enable us 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):

2020-02-16 The Boeing Company: Amendment 39-19830; Docket No. FAA-
2019-0670; Product Identifier 2019-NM-104-AD.

(a) Effective Date

    This AD is effective March 18, 2020.

(b) Affected ADs

    None.

[[Page 7868]]

(c) Applicability

    (1) This AD applies to The Boeing Company Model 737-200, -200C, 
-300, -400, and -500 series airplanes, certificated in any category, 
as identified in Boeing Alert Requirements Bulletin 737-53A1382 RB, 
dated May 6, 2019.
    (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.

(e) Unsafe Condition

    This AD was prompted by an evaluation by the design approval 
holder (DAH) indicating that the lower skin of the fuselage skin lap 
splices along the lower fastener row of the stringer (S)-14 lap 
splice on certain body station skin panels may be subject to 
widespread fatigue damage (WFD). The FAA is issuing this AD to 
address scratch cracks and fatigue cracking, which may interact and 
could result in rapid 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

    Except as specified by paragraph (h) of this AD: At the 
applicable times specified in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin 737-53A1382 RB, dated May 6, 2019, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-53A1382 RB, dated May 6, 2019.

    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
737-53A1382, dated May 6, 2019, which is referred to in Boeing Alert 
Requirements Bulletin 737-53A1382 RB, dated May 6, 2019.

(h) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Requirements Bulletin 737-53A1382 RB, 
dated May 6, 2019, uses the phrase ``the original issue date of 
Requirements Bulletin 737-53A1382 RB,'' this AD requires using ``the 
effective date of this AD.''
    (2) Where Boeing Alert Requirements Bulletin 737-53A1382 RB, 
dated May 6, 2019, 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) Terminating Action for the Required Inspections

    Accomplishment of certain skin panel replacements identified as 
terminating action in Boeing Alert Requirements Bulletin 737-53A1382 
RB, dated May 6, 2019, terminates the inspections required by this 
AD, in the corresponding locations.

(j) 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 (k)(1) of this AD. Information 
may be emailed to: 9-ANM-LAACO-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, 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.

(k) Related Information

    (1) For more information about this AD, contact James Guo, 
Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
5357; fax: 562-627-5210; email: james.guo@faa.gov.
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (l)(3) and (4) of this AD.

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Alert Requirements Bulletin 737-53A1382 RB, dated May 
6, 2019.
    (ii) [Reserved]
    (3) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Contractual & Data Services 
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-
5600; phone: 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 fedreg.legal@nara.gov, or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on January 27, 2020.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2020-02719 Filed 2-11-20; 8:45 am]
 BILLING CODE 4910-13-P


