
[Federal Register: March 23, 2009 (Volume 74, Number 54)]
[Proposed Rules]               
[Page 12100-12102]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr23mr09-16]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0160; Directorate Identifier 2008-NM-176-AD]
RIN 2120-AA64

 
Airworthiness Directives; McDonnell Douglas Model MD-90-30 
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 
McDonnell Douglas Model MD-90-30 airplanes. This proposed AD would 
require repetitive inspections for cracks of the upper aft skin panels 
on the horizontal stabilizer, and related investigative and corrective 
actions if necessary. This proposed AD results from a report of cracks 
found in the aft skin panels on the upper right side of the horizontal 
stabilizer at the aft inboard corner. We are proposing this AD to 
detect and correct cracks in the fail-safe structure that may not be 
able to sustain limit load, which could result in the loss of overall 
structural integrity of the horizontal stabilizer.

DATES: We must receive comments on this proposed AD by May 7, 2009.

ADDRESSES: You may send comments 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: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    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; e-mail 
dse.boecom@boeing.com; 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 or 425-227-1152.

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 (telephone 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, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; 
telephone (562) 627-5233; fax (562) 627-5210.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2009-0160; 
Directorate Identifier 2008-NM-176-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 a report that one operator found two instances of 
a crack in the aft skin panel on the upper right side of the horizontal 
stabilizer at the aft inboard corner. The airplanes had accumulated 
16,659 total flight cycles/31,403 total flight hours and 18,128 total 
flight cycles/33,959 total flight hours. The cause of the cracking on 
the aft skin panel on the upper right side of the horizontal stabilizer 
is suspected to be fatigue. This condition, if not detected and 
corrected, could result in cracks in the fail-safe structure that may 
not be able to sustain limit load, which could result in the loss of 
overall structural integrity of the horizontal stabilizer.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin MD90-55A012, dated 
September 23, 2008. The service bulletin describes procedures for 
repetitive eddy current inspections to detect cracks on the upper aft 
skin panels on the left and right sides of the horizontal stabilizer, 
and related investigative and corrective actions. The initial 
compliance time is 13,500 total flight cycles or 24 months after the 
effective date of this AD, whichever occurs later. The related 
investigative actions include repetitive eddy current inspections for 
cracks of the rear spar upper caps of the left and right sides of the 
horizontal stabilizer. The repetitive interval for the inspection is 
within 1,600 or 2,100 flight cycles, depending on the previous 
inspection method used.
    Corrective actions include, depending on crack findings and crack 
location, installing the upper aft skin panel splice of the horizontal 
stabilizer, and replacing the upper aft skin panel of the horizontal 
stabilizer. The service bulletin describes three options, depending on 
crack findings and crack location:
     (Option 1) The service bulletin describes procedures for a 
high frequency eddy current inspection of the rear spar cap of the 
horizontal stabilizer and installation of the upper aft skin panel 
splice of the horizontal stabilizer before further flight, and an eddy 
current inspection on the upper aft skin panel of the horizontal 
stabilizer within 13,500 flight cycles after the installation. If the 
crack is on the rear spar cap of the horizontal stabilizer, the service 
bulletin specifies to contact

[[Page 12101]]

Boeing for repair instructions and do the repair before further flight.
     (Option 2) The service bulletin describes procedures for a 
high frequency eddy current inspection of the rear spar cap of the 
horizontal stabilizer, remove and replace the upper aft skin panel of 
the horizontal stabilizer before further flight, and an eddy current 
inspection of the upper aft skin panel of the horizontal stabilizer 
within 13,500 flight cycles. If the crack is on the rear spar cap of 
the horizontal stabilizer, the service bulletin specifies to contact 
Boeing for further repair instructions and do the repair before further 
flight.
     (Option 3) The service bulletin specifies one option is to 
contact Boeing for possible temporary repair of skin cracks and do the 
repair before further flight.

FAA's Determination and Requirements of This Proposed AD

    We are proposing this AD because we evaluated all relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the(se) same type 
design(s). This proposed AD would require accomplishing the actions 
specified in the service information described previously, except as 
discussed under ``Difference Between the Proposed AD and Service 
Bulletin.''

Difference Between the Proposed AD and Service Bulletin

    Boeing Alert Service Bulletin MD90-55A012, dated September 23, 
2008, 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:
     Using a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by an Authorized Representative 
for the Boeing Commercial Airplanes Delegation Option Authorization 
Organization whom we have authorized to make those findings.

Costs of Compliance

    We estimate that this proposed AD would affect 16 airplanes of U.S. 
registry. The following table provides the estimated costs for U.S. 
operators to comply with this proposed AD.

                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                     Number of
                                                      Average                                                          U.S.-
                Action                  Work hours   labor rate            Parts              Cost per airplane      registered         Fleet cost
                                                      per hour                                                       airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspection...........................            4          $80  None....................  $320 per inspection               16  $5,120 per inspection
                                                                                            cycle.                                cycle.
--------------------------------------------------------------------------------------------------------------------------------------------------------

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), 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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

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 AD:

McDonnell Douglas: Docket No. FAA-2009-0160; Directorate Identifier 
2008-NM-176-AD.

Comments Due Date

    (a) We must receive comments by May 7, 2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Boeing Model MD-90-30 airplanes, 
certificated in any category.

Subject

    (d) Air Transport Association (ATA) of America Code 55: 
Stabilizers.

Unsafe Condition

    (e) This AD results from a report of cracks found in the right 
upper aft skin panel of the horizontal stabilizer at the aft inboard 
corner. We are issuing this AD to detect and correct cracks in the 
fail-safe structure that may not be able to sustain limit load, 
which could result in the loss of overall structural integrity of 
the horizontal stabilizer.

Compliance

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

[[Page 12102]]

Inspections

    (g) Except as required by paragraphs (h) and (i) of this AD: At 
the times specified in paragraph 1.E., ``Compliance,'' of Boeing 
Alert Service Bulletin MD90-55A012, dated September 23, 2008, do an 
eddy current inspection for cracks of the upper aft skin panels on 
the left and right sides of the horizontal stabilizer, and do all 
applicable related investigative and corrective actions, in 
accordance with the Accomplishment Instructions of the service 
bulletin.

Exceptions to Service Bulletin Specifications

    (h) Where Boeing Alert Service Bulletin MD90-55A012, dated 
September 23, 2008, specifies a compliance time after the date on 
the service bulletin, this AD requires compliance within the 
specified compliance time after the effective date of this AD.
    (i) If any crack is found during any inspection required by this 
AD, and Boeing Alert Service Bulletin MD90-55A012, dated September 
23, 2008, specifies to contact Boeing for appropriate action: Before 
further flight, repair using a method approved in accordance with 
the procedures specified in paragraph (k) of this AD.

Inspections Done According to Multi-Operator Message

    (j) Inspections and corrective actions done before the effective 
date of this AD are acceptable for compliance with the corresponding 
requirements of this AD, if done in accordance with Boeing Multi-
Operator Message 1-669017091-1, dated November 9, 2007.

Alternative Methods of Compliance (AMOCs)

    (k)(1) The Manager, Los Angeles Aircraft Certification Office, 
FAA, ATTN: Roger Durbin, Aerospace Engineer, Airframe Branch, ANM-
120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount 
Boulevard, Lakewood, California 90712-4137; telephone (562) 627-
5233; fax (562) 627-5210; has the authority to approve AMOCs for 
this AD, if requested using the procedures found in 14 CFR 39.19.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your principal maintenance inspector (PMI) or 
principal avionics inspector (PAI), as appropriate, in the FAA 
Flight Standards District Office (FSDO), or lacking a principal 
inspector, your local FSDO. The AMOC approval letter must 
specifically reference this AD.
    (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 an 
Authorized Representative for the Boeing Commercial Airplanes 
Delegation Option Authorization Organization who has been authorized 
by the Manager, International Branch, 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.

    Issued in Renton, WA, on March 6, 2009.
Linda Navarro,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E9-6218 Filed 3-20-09; 8:45 am]

BILLING CODE 4910-13-P
