
[Federal Register Volume 80, Number 121 (Wednesday, June 24, 2015)]
[Proposed Rules]
[Pages 36258-36261]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-15398]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-1983; Directorate Identifier 2015-NM-020-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 737-100, -200, -200C, -300, -400, and -500 
series airplanes. This proposed AD was prompted by a report of a crack 
of the forward leg of the left front spar lower chord and cracks on the 
lower wing skin at three fastener holes common to the nacelle outboard 
side load fitting. This proposed AD would require repetitive 
inspections for cracks on the front spar lower chord, inspar skin, and 
wing skin, and corrective action if necessary. We are proposing this AD 
to detect and correct fatigue cracking of the forward leg of the front 
spar lower chord, inspar skin, and wing skin common to the nacelle 
outboard side load fitting, which could adversely affect the structural 
integrity of the wing.

DATES: We must receive comments on this proposed AD by August 10, 2015.

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 proposed 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 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 2015-
1983.

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-2015-
1983; 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: Alan Pohl, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6450; fax: 
425-917-6590; email: alan.pohl@faa.gov.

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-2015-1983; 
Directorate Identifier 2015-NM-020-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 received a report of a crack on the forward leg of the left 
front spar lower chord at wing buttock line (WBL) 177. The front spar 
lower chord was removed, repaired, and reinstalled. Upon additional 
inspection of the repaired spar chord installation, cracks were also 
discovered on the lower wing

[[Page 36259]]

skin at three fastener holes common to the nacelle outboard side load 
fitting at WBL 198.6. These cracks were identified on an airplane that 
had accumulated 57,617 total flight cycles. Metallurgical analysis of 
the chord determined that cracks initiated at fastener holes and were 
propagated by operating load fatigue. The analysis found no anomalies 
that could have contributed to the cracking. Fatigue cracking of the 
forward leg of the left front spar lower chord, inspar skin, and lower 
wing skin common to the nacelle outboard side load fitting, if not 
corrected, could adversely affect the structural integrity of the wing.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-57A1323, dated 
December 5, 2014. The service information describes procedures for 
repetitive inspections for cracks on the left and right wing front spar 
lower chord, inspar skin, and wing skin and corrective action if 
necessary. 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 of this 
NPRM.

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 these same type 
designs.

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.'' Refer to this service information for details on the 
procedures and compliance times.
    The phrase ``corrective actions'' is used in this proposed AD. 
``Corrective actions'' are actions that 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 737-57A1323, dated December 5, 2014, 
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.
    For Group 2 and 3 airplanes identified in Boeing Alert Service 
Bulletin 737-57A1323, dated December 5, 2014, paragraph (h) of this 
proposed AD specifies repeating the detailed inspection for cracks on 
the left and right wing front spar lower chord and inspar skin 
inspection, except in areas repaired in accordance with the procedures 
specified in paragraph (k) of this AD.

Explanation of Required for Compliance (RC) Steps in Service 
Information

    The FAA worked in conjunction with industry, under the 
Airworthiness Directive Implementation Aviation Rulemaking Committee 
(ARC), to enhance the AD system. One enhancement was a new process for 
annotating which steps in the service information are required for 
compliance with an AD. Differentiating these steps from other tasks in 
the service information is expected to improve an owner's/operator's 
understanding of crucial AD requirements and help provide consistent 
judgment in AD compliance. The steps identified as RC (required for 
compliance) in any service information identified previously have a 
direct effect on detecting, preventing, resolving, or eliminating an 
identified unsafe condition.
    For service information that contains steps that are labeled as 
Required for Compliance (RC), the following provisions apply: (1) 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, 
and an AMOC is required for any deviations to RC steps, including 
substeps and identified figures; and (2) 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.

Costs of Compliance

    We estimate that this proposed AD affects 331 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
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                                                                                                 Cost on U.S.
             Action                     Labor cost          Parts cost     Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Inspection (28 Group 2           7 work[dash]hours x $85              $0  $595 per            $16,660 per
 airplanes).                      per hour = $595 per                      inspection cycle.   inspection cycle.
                                  inspection cycle.
Inspection and fastener          Up to 94                              0  Up to $7,990 per    Up to $2,412,980
 installation (302 Group 3        work[dash]hours x $85                    inspection cycle.   per inspection
 airplanes).                      per hour = $7,990 per                                        cycle.
                                  inspection cycle.
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    We have received no definitive data that would enable us to provide 
cost estimates for the actions specified for the Group 1 airplane in 
this proposed AD.
    We also have received no definitive data that would enable us to 
provide cost estimates for the 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

[[Page 36260]]

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.

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-2015-1983; Directorate Identifier 
2015-NM-020-AD.

(a) Comments Due Date

    We must receive comments by August 10, 2015.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737-100, -200, -
200C, -300, -400, and -500 series airplanes, certificated in any 
category.

 (d) Subject

    Air Transport Association (ATA) of America Code 57, Wings.

(e) Unsafe Condition

    This AD was prompted by a report of a crack in the forward leg 
of the left front spar lower chord and cracks on the lower wing skin 
at three fastener holes common to the nacelle outboard side load 
fitting. We are issuing this AD to detect and correct fatigue 
cracking of the forward leg of the front spar lower chord, inspar 
skin, and wing skin common to the nacelle outboard side load 
fitting, which could adversely affect the structural integrity of 
the wing.

(f) Compliance

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

(g) Inspections and Corrective Actions for Group 1 Airplanes

    For Group 1 airplanes identified in Boeing Alert Service 
Bulletin 737-57A1323, dated December 5, 2014: Within 120 days after 
the effective date of this AD, do inspections of the left and right 
wing front spar lower chord and inspar skin, and the left and right 
wing nacelle outboard side load fitting fastener holes common to the 
front spar lower chord and skin, and do all applicable corrective 
actions, using a method approved in accordance with the procedures 
specified in paragraph (k) of this AD.

(h) Repetitive Detailed Inspections and Corrective Actions

    For Group 2 and 3 airplanes identified in Boeing Alert Service 
Bulletin 737-57A1323, dated December 5, 2014: Except as provided by 
paragraph (j)(1) of this AD, at the applicable time specified in 
Table 1 of paragraph 1.E., ``Compliance,'' of Boeing Alert Service 
Bulletin 737-57A1323, dated December 5, 2014, do a detailed 
inspection for cracks on the left and right wing front spar lower 
chord and inspar skin, and do all applicable corrective actions, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-57A1323, dated December 5, 2014, except as 
specified in paragraph (j)(2) of this AD. Do all applicable 
corrective actions before further flight. Repeat the inspection 
thereafter at the applicable interval specified in Table 1 of 
paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin 
737-57A1323, dated December 5, 2014, except in areas repaired in 
accordance with the procedures specified in paragraph (k) of this 
AD.

(i) Repetitive High Frequency Eddy Current (HFEC) Inspections and 
Corrective Actions

    For Group 3 airplanes identified in Boeing Alert Service 
Bulletin 737-57A1323, dated December 5, 2014: Except as provided by 
paragraph (j)(1) of this AD, at the applicable time specified in 
Table 2 or Table 3 of paragraph 1.E., ``Compliance,'' of Boeing 
Alert Service Bulletin 737-57A1323, dated December 5, 2014, do the 
actions specified in paragraphs (i)(1) or (i)(2) of this AD. Repeat 
the inspection specified in either paragraph (i)(1) or (i)(2) of 
this AD thereafter at the applicable interval specified in Table 2 
or Table 3 of paragraph 1.E., ``Compliance,'' of Boeing Alert 
Service Bulletin737-57A1323, dated December 5, 2014.
    (1) Do an HFEC open hole probe inspection for cracks of the left 
and right wing nacelle outboard side load fitting fastener holes 
common to the front spar lower chord and skin, and perform all 
applicable corrective actions, in accordance with Part 2, Option 1 
of the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-57A1323, dated December 5, 2014, except as provided by paragraph 
(j)(2) of this AD. Do all applicable corrective actions before 
further flight.
    (2) Do an HFEC surface probe inspection for cracks in the wing 
inspar skin, and perform all applicable corrective actions, in 
accordance with Part 2, Option 2 of the Accomplishment Instructions 
of Boeing Alert Service Bulletin 737-57A1323, dated December 5, 
2014, except as provided by paragraph (j)(2) of this AD. Do all 
applicable corrective actions before further flight.

(j) Exceptions to Service Information Specifications

    (1) Where paragraph 1.E., ``Compliance,'' of Boeing Alert 
Service Bulletin 737-57A1323, dated December 5, 2014, 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) Although Boeing Alert Service Bulletin 737-57A1323, dated 
December 5, 2014, specifies to contact Boeing for repair 
instructions, and specifies that action as ``RC'' (Required for 
Compliance), this AD requires repair before further flight 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 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 (l)(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 required by this AD if it is approved by the 
Boeing Commercial Airplanes Organization Designation Authorization 
that has been authorized by the Manager, Los Angeles ACO, to make 
those findings. For a repair method to be approved, the repair 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

[[Page 36261]]

contains steps that are labeled as Required for Compliance (RC), the 
provisions of paragraphs (k)(4)(i) and (k)(4)(ii) 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

(l) Related Information

    (1) For more information about this AD, contact Alan Pohl, 
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; 
phone: 425-917-6450; fax: 425-917-6590; email: alan.pohl@faa.gov.
    (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 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 June 12, 2015.
Jeffrey E. Duven,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2015-15398 Filed 6-23-15; 8:45 am]
 BILLING CODE 4910-13-P


