81 FR 85113 - Airworthiness Directives; The Boeing Company Airplanes

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration

Federal Register Volume 81, Issue 227 (November 25, 2016)

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-400 series airplanes. This AD was prompted by reports of cracks in the upper chord of the overwing stub beams at body station (STA) 578 emanating from the rivet location common to the crease beam inner chord and the overwing stub beam upper chord. This AD requires repetitive inspections for cracking, and related investigative and corrective actions if necessary. We are issuing this AD to prevent the unsafe condition on these products.

[Federal Register Volume 81, Number 227 (Friday, November 25, 2016)]
[Rules and Regulations]
[Pages 85113-85116]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2016-27640]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-5597; Directorate Identifier 2016-NM-009-AD; 
Amendment 39-18715; AD 2016-23-08]
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 all The 
Boeing Company Model 737-400 series airplanes. This AD was prompted by 
reports of cracks in the upper chord of the overwing stub beams at body 
station (STA) 578 emanating from the rivet location common to the 
crease beam inner chord and the overwing stub beam upper chord. This AD 
requires repetitive inspections for cracking, and related investigative 
and corrective actions if necessary. We are issuing this AD to prevent 
the unsafe condition on these products.

DATES: This AD is effective December 30, 2016.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of December 30, 
2016.

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 referenced service information 
at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., 
Renton, WA. You may view this referenced service information at the 
FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. 
For information on the availability of this material at the FAA, call 
425-227-1221. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-
5597.

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-2016-
5597; or in person at the Docket Management Facility between 9 a.m. and 
5 p.m., Monday through Friday,

[[Page 85114]]

except Federal holidays. The AD docket contains this AD, the regulatory 
evaluation, any comments received, and other information. The address 
for the Docket Office (phone: 800-647-5527) is Docket Management 
Facility, 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: Galib Abumeri, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office (ACO), 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 
562-627-5324; 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 all The Boeing Company 
Model 737-400 series airplanes. The NPRM published in the Federal 
Register on April 28, 2016 (81 FR 25360) (``the NPRM''). The NPRM was 
prompted by reports of cracks in the upper chord of the overwing stub 
beams at STA 578 emanating from the rivet location common to the crease 
beam inner chord and the overwing stub beam upper chord. The NPRM 
proposed to require repetitive inspections for cracking, and related 
investigative and corrective actions if necessary. Replacement of the 
overwing stub beam terminates the repetitive inspections for cracking 
at the replacement location only, and post-replacement inspections are 
required if the replacement is done. We are issuing this AD to detect 
and correct cracking in the upper chord of the overwing stub beam 
caused by high flight-cycle fatigue stresses from both pressurization 
and maneuver loads. Cracking of the overwing stub beam could adversely 
affect the fuselage structural integrity and result in possible 
decompression of the airplane.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the NPRM and 
the FAA's response to each comment.

Request To Clarify Unsafe Condition Statement in the ``Discussion'' 
Section

    Boeing requested that, in the ``Discussion'' section of the NPRM, 
that we clarify the cause of cracking in the overwing stub beams is 
from high flight-cycle fatigue stresses. Boeing submitted suggested 
wording.
    We agree to clarify the unsafe condition. The unsafe condition 
statement in the SUMMARY section of the NPRM and paragraph (e) of the 
proposed AD already specified that the cracking in the upper chord of 
the overwing stub beam is caused by high flight-cycle fatigue stresses 
from both pressurization and maneuver loads. However, the 
``Discussion'' section of the NPRM is not restated in this final rule. 
Therefore, we have not revised this final rule in this regard.

Request To Revise Paragraph (i) of the NPRM

    Boeing requested that we revise paragraph (i) of the proposed AD to 
specify that the actions in that paragraph are required on airplanes 
that have had an overwing stub beam replaced at STA 578 as specified in 
Part 4 of the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1347, Original Issue, dated December 9, 2015 (``ASB 
737-53A1347 Original Issue''), and not replaced with any other method. 
Boeing stated that the post-replacement inspection requirements 
specified in table 2 of paragraph 1.E., ``Compliance,'' of ASB 737-
53A1347 Original Issue are applicable only to a STA 578 stub beam 
replacement accomplished as specified in Part 4 of the Accomplishment 
Instructions of ASB 737-53A1347 Original Issue.
    We agree with Boeing's request. We have revised paragraph (i) 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 AD with the changes described previously and minor editorial 
changes. We have determined that these minor changes:
     Are consistent with the intent that was proposed in the 
NPRM or correcting the unsafe condition; and
     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 AD.

Related Service Information Under 1 CFR Part 51

    We reviewed ASB 737-53A1347 Original Issue. The service information 
describes procedures for doing a surface high frequency eddy current 
inspection for cracking in the overwing stub beam upper chord at STA 
559, STA 578, and STA 601, and repairs and replacement. 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 93 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
               Action                         Labor cost            Parts cost       Cost per product                 Cost on U.S. operators
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspection.........................  24 work-hours x $85 per                  $0  $2,040 per inspection   $189,720 per inspection cycle.
                                      hour = $2,040 per                            cycle.
                                      inspection cycle.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary inspections/
replacements that would be required based on the results of the 
inspection. We have no way of determining the number of aircraft that 
might need these inspections/replacements:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
             Action                  Labor cost                Parts cost                 Cost per product
----------------------------------------------------------------------------------------------------------------
Related investigative            9 work-hours x $85  $0...........................  $765 per side.
 inspection.                      per hour = $765
                                  per side.

[[Page 85115]]

 
STA 578 Replacement............  41 work-hours x     $41,500 per side.............  $44,985 per side.
                                  $85 per hour =
                                  $3,485 per side.
STA 578 Post[dash]replacement    1 work-hour x $85   $0...........................  $85 per side.
 inspection.                      per hour = $85
                                  per side.
----------------------------------------------------------------------------------------------------------------

    We have received no definitive data that would enable us to provide 
cost estimates for the remaining 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.

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):

2016-23-08 The Boeing Company: Amendment 39-18715; Docket No. FAA-
2016-5597; Directorate Identifier 2016-NM-009-AD.

(a) Effective Date

    This AD is effective December 30, 2016.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all the Boeing Company Model 737-400 series 
airplanes, certificated in any category.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by reports of cracks in the upper chord of 
the overwing stub beams at body station (STA) 578 emanating from the 
rivet location common to the crease beam inner chord and the 
overwing stub beam upper chord. We are issuing this AD to detect and 
correct cracking in the upper chord of the overwing stub beam caused 
by high flight-cycle fatigue stresses from both pressurization and 
maneuver loads. Cracking of the overwing stub beam could adversely 
affect the fuselage structural integrity and result in possible 
decompression of the airplane.

(f) Compliance

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

(g) Inspections, Related Investigative Actions, and Corrective Actions

    At the applicable time specified in table 1 in paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1347, 
Original Issue, dated December 9, 2015 (``ASB 737-53A1347 Original 
Issue''), except as required by paragraphs (j)(1) and (j)(2) of this 
AD: Do a surface high frequency eddy current (HFEC) inspection for 
any cracking in the overwing stub beam upper chord at STA 559, STA 
578, and STA 601; and do all applicable related investigative and 
corrective actions; in accordance with the Accomplishment 
Instructions of ASB 737-53A1347 Original Issue, except as specified 
in paragraph (j)(3) of this AD. Do all applicable related 
investigative and corrective actions before further flight. Repeat 
the HFEC inspection thereafter at the applicable intervals specified 
in ASB 737-53A1347 Original Issue.

    Note 1 to paragraph (g) of this AD:  Deviation from the actions 
specified in ASB 737-53A1347 Original Issue may affect compliance 
with the fuel tank ignition prevention requirements specified in 
Critical Design Configuration Control Limitation 28-AWL-11 of 
Document D6-38278-CMR.

(h) Terminating Action

    Replacement of the overwing stub beam, in accordance with Part 4 
of the Accomplishment Instructions of ASB 737-53A1347 Original 
Issue, terminates the repetitive inspections required by paragraph 
(g) of this AD at the STA 578 replacement location only. The post-
replacement inspections required by paragraph (i) of this AD are 
still required at the STA 578 replacement location.

(i) Post-Replacement Inspections and Corrective Action

    For airplanes on which an overwing stub beam has been replaced 
at STA 578, in accordance with Part 4 of the Accomplishment 
Instructions of ASB 737-53A1347 Original Issue: At the applicable 
time specified in table 2 in paragraph 1.E., ``Compliance,'' of ASB 
737-53A1347 Original Issue, do a surface HFEC inspection for any 
cracking in the overwing stub beam upper chord at STA 578, in 
accordance with the Accomplishment Instructions of ASB 737-53A1347 
Original Issue. Repeat the HFEC inspection thereafter at the 
applicable intervals specified in ASB 737-53A1347 Original Issue. If 
any cracking is found during any inspection required by this 
paragraph, before further flight, repair the cracking using a method 
approved in accordance with the procedures specified in paragraph 
(j)(3) of this AD.

(j) Exceptions to Service Information

    (1) Where ASB 737-53A1347 Original Issue, specifies a compliance 
time after the ``original issue date of this service bulletin,'' 
this AD requires compliance within the specified compliance time 
after the effective date of this AD.
    (2) The Condition column of paragraph 1.E., ``Compliance,'' of 
ASB 737-53A1347

[[Page 85116]]

Original Issue, refers to airplanes with specified total flight-
cycles ``at the original issue date of this service bulletin.'' This 
AD, however, applies to the airplanes with the specified total 
flight-cycles as of the effective date of this AD.
    (3) If any cracking is found during any inspection required by 
this AD, and ASB 737-53A1347 Original Issue specifies to contact 
Boeing for appropriate action: Before further flight, repair the 
cracking or replace the stub beam, using a method approved in 
accordance with the procedures specified in paragraph (l) of this 
AD.

(k) No Economic Inspection Required

    This AD does not require the ``Recommended Economic Inspection'' 
specified in paragraph 3.B.3. of the Accomplishment Instructions of 
ASB 737-53A1347 Original Issue.

(l) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles Aircraft Certification Office 
(ACO), 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 ACO, send it to the 
attention of the person identified in paragraph (m) 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, 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)(3) of this AD: For 
service information that contains steps that are labeled as Required 
for Compliance (RC), the provisions of paragraphs (l)(4)(i) and 
(l)(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.

(m) Related Information

    For more information about this AD, contact Galib Abumeri, 
Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles 
Aircraft Certification Office (ACO), 3960 Paramount Boulevard, 
Lakewood, CA 90712-4137; phone: 562-627-5324; fax: 562-627-5210; 
email: [email protected].

(n) 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 737-53A1347, Original Issue, 
dated December 9, 2015.
    (ii) Reserved.
    (3) For Boeing 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 
Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For 
information on the availability of this material at the FAA, call 
425-227-1221.
    (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 Renton, Washington, on November 8, 2016.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-27640 Filed 11-23-16; 8:45 am]
 BILLING CODE 4910-13-P