
[Federal Register Volume 77, Number 148 (Wednesday, August 1, 2012)]
[Proposed Rules]
[Pages 45515-45517]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-18616]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2012-0728; Directorate Identifier 2012-NM-050-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 
certain The Boeing Company Model MD-90-30 airplanes. This proposed AD 
was prompted by reports of fatigue cracks found in Stringer 11 at the 
outboard flap, inboard drive hinge at Station Xrs=164.000. This 
proposed AD would require repetitive inspections for cracks in Stringer 
11, and a splice repair if necessary; and repetitive post-repair 
inspections, and repair if necessary. We are proposing this AD to 
detect and correct such cracking, which could result in the wing 
structure not supporting the limit load condition, which could lead to 
loss of the structural integrity of the wing.

DATES: We must receive comments on this proposed AD by September 17, 
2012.

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,

[[Page 45516]]

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, 
3855 Lakewood Boulevard, MC D800-0019, Long Beach, California 90846-
0001; telephone 206-544-5000, extension 2; fax 206-766-5683; Internet 
https://www.myboeingfleet.com. You may review copies of the referenced 
service information at the FAA, Transport Airplane Directorate, 1601 
Lind Avenue SW., Renton, Washington. For information on the 
availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; 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: Roger Durbin, Airframe Branch, ANM-
120L, FAA, Los Angeles Aircraft Certification Office (ACO), 3960 
Paramount Boulevard, Lakewood, California 90712-4137; phone: (562) 627-
5233; fax: (562) 627-5210; email: roger.durbin@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-2012-0728; 
Directorate Identifier 2012-NM-050-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 reports of fatigue cracks found in Stringer 11 at the 
outboard flap, inboard drive hinge at Station Xrs=164.000 on Model MD-
80 airplanes. Model MD-90 airplanes share the same structure design as 
the MD-80, and are also susceptible to cracking. The cracking occurred 
at the end fastener of the wing bulkhead clip attachment to the 
stringer. If undetected, a crack in the stringer may grow until the 
stringer severs, initiating a crack in the wing lower skin. This 
condition, if not corrected, could result in the wing structure not 
supporting the limit load condition, which could lead to loss of the 
structural integrity of the wing.

Relevant Service Information

    We reviewed Boeing Alert Service Bulletin MD90-57A030, dated 
February 14, 2012. The service information describes procedures for 
repetitive in-tank eddy current high frequency (ETHF) inspections for 
cracks in Stringer 11 at the outboard flap, inboard drive hinge at 
Station Xrs=164.000 on the left and right wings, and a splice repair if 
necessary; and repetitive post-repair inspections, and repair if 
necessary.

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 this 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 the Proposed AD and the Service 
Information.

Differences Between the Proposed AD and the Service Information

    The service bulletin 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 52 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.......................  13 work-hours x $85   None.........  $1,105 per           $57,460 per
                                    per hour = $1,105                    inspection cycle.    inspection cycle.
                                    per inspection
                                    cycle.
Post-repair inspection...........  13 work-hours x $85   None.........  $1,105.............  $57,460.
                                    per hour = $1,105.
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary repairs 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 
repairs:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                   Action                                 Labor cost                Parts cost        product
----------------------------------------------------------------------------------------------------------------
Splice repair per wing.....................  93 work-hours x $85 per hour =              $28,126         $36,031
                                              $7,905.
----------------------------------------------------------------------------------------------------------------


[[Page 45517]]

    We have received no definitive data that would enable us to provide 
cost estimates for the on-condition actions of the post-repair 
inspection 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.

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

    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]

    2. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

The Boeing Company: Docket No. FAA-2012-0728; Directorate Identifier 
2012-NM-050-AD.

(a) Comments Due Date

    We must receive comments by September 17, 2012.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model MD-90-30 airplanes, 
certificated in any category, as identified in Boeing Alert Service 
Bulletin MD90-57A030, dated February 14, 2012.

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 57, Wings.

(e) Unsafe Condition

    This AD was prompted by reports of fatigue cracks found in 
Stringer 11 at the outboard flap, inboard drive hinge at Station 
Xrs=164.000. We are issuing this AD to detect and correct such 
cracking, which could result in the wing structure not supporting 
the limit load condition, which could lead to loss of the structural 
integrity of the wing.

(f) Compliance

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

(g) Repetitive Inspections

    Before the accumulation of 14,000 total flight cycles, or within 
9,470 flight cycles after the effective date of this AD: Whichever 
occurs later, do an in-tank eddy current high frequency (ETHF) 
inspection for cracks in Stringer 11 at the outboard flap, inboard 
drive hinge at Station Xrs=164.000 of the left and right wings, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin MD90-57A030, dated February 14, 2012. If no 
cracking is found, repeat the inspection thereafter at intervals not 
to exceed 31,000 flight cycles.

(h) Splice Repair

    If any cracking is found during the inspection required by 
paragraph (g) of this AD: Before further flight, do a splice repair, 
in accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin MD90-57A030, dated February 14, 2012.

(i) Post-Repair Inspection

    Within 42,000 flight cycles after doing the splice repair 
specified in paragraph (h) of this AD: Do an ETHF inspection for 
cracks in Stringer 11 at the outboard flap, inboard drive hinge at 
Station Xrs=164.000, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin MD90-57A030, dated 
February 14, 2012. Repeat the inspection thereafter at intervals not 
to exceed 31,000 flight cycles. If any crack is found: Before 
further flight, repair the crack using a method approved in 
accordance with the procedures specified in paragraph (j) of this 
AD.

(j) 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 the Related Information 
section of this AD.
    (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 
(ODA) 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 14 CFR 
25.571, Amendment 54, and the approval must specifically refer to 
this AD.

(k) Related Information

    (1) For more information about this AD, contact Roger Durbin, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office (ACO), 3960 Paramount Boulevard, Lakewood, California 90712-
4137; phone: (562) 627-5233; fax: (562) 627-5210; email: 
roger.durbin@faa.gov.
    (2) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
3855 Lakewood Boulevard, MC D800-0019, Long Beach, California 90846-
0001; telephone 206-544-5000, extension 2; fax 206-766-5683; 
Internet https://www.myboeingfleet.com. You may review copies of the 
referenced service information at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue SW., Renton, Washington. For 
information on the availability of this material at the FAA, call 
425-227-1221.

    Issued in Renton, Washington, on July 23, 2012.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-18616 Filed 7-31-12; 8:45 am]
BILLING CODE 4910-13-P


