81 FR 25360 - Airworthiness Directives; The Boeing Company Airplanes

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration

Federal Register Volume 81, Issue 82 (April 28, 2016)

We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model 737-400 series airplanes. This proposed 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 proposed AD would require repetitive inspections for cracking, and related investigative and corrective actions if necessary. Replacement of the overwing stub beam would terminate the repetitive inspections for cracking at the replacement location only, and post-replacement inspections would be required if the replacement was done. We are proposing 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.

[Federal Register Volume 81, Number 82 (Thursday, April 28, 2016)]
[Proposed Rules]
[Pages 25360-25363]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2016-09643]


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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]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for all 
The Boeing Company Model 737-400 series airplanes. This proposed 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 proposed AD would require repetitive inspections for 
cracking, and related investigative and corrective actions if 
necessary. Replacement of the overwing stub beam would terminate the 
repetitive inspections for cracking at the replacement location only, 
and post-replacement inspections would be required if the replacement 
was done. We are proposing 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.

DATES: We must receive comments on this proposed AD by June 13, 2016.

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 http://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: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, contact Boeing 
Commercial Airplanes, Attention: Data & Services Management, P.O. Box 
3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544-5000, 
extension 1; fax 206-766-5680; Internet https://www.myboeingfleet.com. 
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, except Federal holidays. The AD docket 
contains this proposed AD, the regulatory evaluation, any comments 
received, and other information. The street address for the Docket 
Office (phone: 800-647-5527) is in the ADDRESSES section. Comments will 
be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Wade Sullivan, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office 
(ACO), 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-
6430; fax: 425-917-6590; email: [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2016-5597; 
Directorate Identifier 2016-NM-009-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    We have received ten reports from four operators of cracks in the 
upper chord of the overwing stub beams at body STA 578 emanating from 
the rivet location common to the crease beam inner chord and the 
overwing stub beam upper chord on The Boeing Company Model 737-400 
series airplanes. The earliest reported crack in an overwing stub beam 
upper chord occurred on an airplane with 31,843 total flight cycles. 
Seven airplanes had a severed overwing stub beam upper chord on either 
the left or right side, and two airplanes had severed overwing stub 
beam upper chords on the left and right sides. Cracks in the upper 
chord of the overwing stub beams, if not corrected, could result in 
high flight cycle fatigue stresses from both pressurization and 
maneuver loads, which can cause cracking in the upper chord of the 
overwing stub beam at STA 559, STA 578, and STA 601. Cracking of the 
overwing stub beam could adversely affect the fuselage structural 
integrity and result in possible decompression of the airplane.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-53A1347, dated 
December 9, 2015. The service information describes procedures for 
doing a surface high frequency eddy current inspection

[[Page 25361]]

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.

FAA's Determination

    We are proposing this AD because we 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.

Proposed AD Requirements

    This proposed AD would require accomplishing the actions specified 
in the service information described previously, except as discussed 
under ``Differences Between this Proposed AD and the Service 
Information.'' For information on the procedures and compliance times, 
see this service information at http://www.regulations.gov by searching 
for and locating Docket No. FAA-2016-5597.
    The phrase ``related investigative actions'' is used in this 
proposed AD. ``Related investigative actions'' are follow-on actions 
that (1) are related to the primary action, and (2) further investigate 
the nature of any condition found. Related investigative actions in an 
AD could include, for example, inspections.
    The phrase ``corrective actions'' is used in this proposed AD. 
``Corrective actions'' correct or address any condition found. 
Corrective actions in an AD could include, for example, repairs.

Differences Between This Proposed AD and the Service Information

    Boeing Alert Service Bulletin 737-53A1347, dated December 9, 2015, 
specifies to contact the manufacturer for instructions on how to repair 
certain conditions, but this proposed AD would require repairing those 
conditions in one of the following ways:
     In accordance with a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by the Boeing Commercial 
Airplanes Organization Designation Authorization (ODA) whom we have 
authorized to make those findings.

Costs of Compliance

    We estimate that this proposed AD affects 93 airplanes of U.S. 
registry. We estimate the following costs to comply with this proposed 
AD:

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

    We estimate the following costs to do any necessary inspections/
replacements that would be required based on the results of the 
proposed 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 inspection.  9 work-hours x $85   $0.........................  $765 per side.
                                    per hour = $765
                                    per side.
STA 578 Replacement..............  41 work-hours x $85  $41,500 per side...........  $44,985 per side.
                                    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 certain 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.
    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

    We 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) Is not a ``significant rule'' under the 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.

[[Page 25362]]

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-2016-5597; Directorate Identifier 
2016-NM-009-AD.

(a) Comments Due Date

    We must receive comments by June 13, 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, dated 
December 9, 2015, 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 Boeing Alert Service Bulletin 737-
53A1347, dated December 9, 2015, 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 Boeing Alert 
Service Bulletin 737-53A1347, dated December 9, 2015.
    Note 1 to paragraph (g) of this AD: Deviation from the actions 
specified in Boeing Alert Service Bulletin 737-53A1347, dated 
December 9, 2015, 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 Boeing Alert Service Bulletin 
737-53A1347, dated December 9, 2015, 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: At the applicable time specified in table 2 in paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-53A1347, 
dated December 9, 2015: 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 Boeing Alert 
Service Bulletin 737-53A1347, dated December 9, 2015. Repeat the 
HFEC inspection thereafter at the applicable intervals specified 
Boeing Alert Service Bulletin 737-53A1347, dated December 9, 2015. 
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 Boeing Alert Service Bulletin 737-53A1347, dated 
December 9, 2015, 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 
Boeing Alert Service Bulletin 737-53A1347, dated December 9, 2015, 
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 Boeing Alert Service Bulletin 737-53A1347, dated 
December 9, 2015, 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 
Boeing Alert Service Bulletin 737-53A1347, dated December 9, 2015.

(l) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle 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)(1) 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, Seattle 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. 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

    (1) For more information about this AD, contact Wade Sullivan, 
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft 
Certification Office (ACO), 1601 Lind Avenue SW., Renton, WA 98057-
3356; phone: 425-917-6430; fax: 425-917-6590; email: 
[email protected].
    (2) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544-
5000, extension 1; fax 206-766-5680; Internet https://www.myboeingfleet.com. You

[[Page 25363]]

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.

    Issued in Renton, Washington, on April 15, 2016.
Victor Wicklund,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-09643 Filed 4-27-16; 8:45 am]
 BILLING CODE 4910-13-P