
[Federal Register Volume 75, Number 246 (Thursday, December 23, 2010)]
[Proposed Rules]
[Pages 80742-80744]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-32207]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-1202; Directorate Identifier 2010-NM-167-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Corporation Model MD-
90-30 Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: We propose to adopt a new airworthiness directive (AD) for all 
Model MD-90-30 airplanes. This proposed AD would require repetitive 
inspections for cracking of the left and right upper center skin panels 
of the horizontal stabilizer, and corrective action if necessary. This 
proposed AD was prompted by a report of a crack found in the upper skin 
panel at the aft inboard corner of a right horizontal stabilizer. We 
are proposing this AD to detect and correct cracks in the horizontal 
stabilizer upper center skin panel. Uncorrected cracks might ultimately 
lead to the loss of overall structural integrity of the horizontal 
stabilizer.

DATES: We must receive comments on this proposed AD by February 7, 
2011.

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: 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; 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.

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, Aerospace Engineer, Los 
Angeles ACO, Airframe Branch, ANM-120L, FAA Los Angeles Aircraft 
Certification Office, 3960 Paramount Blvd, Lakewood, CA 90712-4137; 
telephone: (562) 627-5233; fax: (562) 627-5210; e-mail: 
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-2010-1202; 
Directorate Identifier 2010-NM-167-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 of a crack to a Model MD-80 airplane 
upper center skin panel of the right horizontal stabilizer at the aft 
inboard corner during an inspection for cracks in the upper and lower 
aft skin panels of the horizontal stabilizer in accordance with AD 
2007-10-04, Amendment 39-15045 (72 FR 25960, May 8, 2007). That 
airplane had accumulated 47,146 total flight hours and 26,490 total 
flight cycles when the crack was found. The cause of the cracking is 
suspected to be fatigue. The Model MD-90-30 airplane horizontal 
stabilizer is similar in design and loading to that of the Model MD-80 
airplane horizontal stabilizer. Therefore, Model MD-90-30 airplanes may 
also be subject to the identified unsafe condition.
    A crack in the upper center skin panel may transfer the load to the 
upper aft skin panel. This may result in the upper aft skin panel 
cracking faster than the existing inspection intervals that are 
required by AD 2009-13-08, Amendment 39-15947 (74 FR 30922, June 29, 
2009). Uncorrected cracking could result in loss of the overall 
structural integrity of the horizontal stabilizer.

Relevant Service Information

    We reviewed Boeing Alert Service Bulletin MD90-55A015, dated July 
16, 2010. This service bulletin describes procedures for repetitive 
eddy current inspections, either (Option 1) two high frequency eddy 
current (ETHF) scans and one low frequency eddy current (ETLF) scan, or 
(Option 2) three ETHF scans, to detect cracking of the right and left 
upper center skin panels of the horizontal stabilizer. Corrective 
actions include replacing any cracked horizontal stabilizer upper 
center skin panel with a serviceable panel or contacting Boeing for 
possible temporary repair instructions.
    The repetitive interval is 5,200 flight cycles or 2,500 flight 
cycles depending on the eddy current inspection option selected.

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 the Proposed AD and the Service 
Information.''

Differences Between the Proposed AD and the Service Information

    Boeing Alert Service Bulletin MD90-55A015, dated July 16, 2010, 
provides an option to contact the manufacturer for instructions on how 
to repair

[[Page 80743]]

cracking, but this proposed AD would require replacing the cracked skin 
panel.

Costs of Compliance

    We estimate that this proposed AD will affect 19 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......................  4 work-hours x $85 per           $0   $340 per inspection  $6,460 per
                                   hour = $340 per                       cycle.               inspection cycle
                                   inspection cycle.
----------------------------------------------------------------------------------------------------------------

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
----------------------------------------------------------------------------------------------------------------
Skin panel replacement.......................  648 work-hours x $85 per hour =            $55,608      $110,688
                                                $55,080.
----------------------------------------------------------------------------------------------------------------

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):

McDonnell Douglas Corporation: Docket No. FAA-2010-1202; Directorate 
Identifier 2010-NM-167-AD.

Comments Due Date

    (a) We must receive comments by February 7, 2011.

Affected ADs

    (b) None.

Applicability

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

Subject

    (d) Joint Aircraft System Component (JASC)/Air Transport 
Association (ATA) of America Code 55: Stabilizers.

Unsafe Condition

    (e) This AD was prompted by a report of a crack found in the 
upper center skin panel at the aft inboard corner of a right 
horizontal stabilizer. We are issuing this AD to detect and correct 
cracks in the upper center skin panel of the horizontal stabilizer. 
Uncorrected cracks might ultimately lead to the loss of overall 
structural integrity of the horizontal stabilizer.

Compliance

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

Inspections

    (g) Before the accumulation of 20,000 total flight cycles, or 
within 3,778 flight cycles after the effective date of this AD, 
whichever occurs later, do eddy current inspections to detect 
cracking of the left and right upper center skin panels of the 
horizontal stabilizer, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin MD90-55A015, dated 
July 16, 2010.
    (1) If no crack is found during any inspection required by 
paragraph (g) of this AD, repeat the applicable inspections 
thereafter at the applicable times specified in paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin MD90-55A015, dated 
July 16, 2010.
    (2) If any crack is found during any inspection required by 
paragraph (g) of this AD, before further flight, replace the skin 
panel with a serviceable skin panel, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin MD90-
55A015, dated July 16, 2010. Within 20,000 flight cycles after the 
replacement, do eddy current inspections as required by paragraph 
(g) of this AD.

Alternative Methods of Compliance (AMOCs)

    (h)(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,

[[Page 80744]]

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 Principal 
Maintenance Inspector or Principal Avionics Inspector, as 
appropriate, or lacking a principal inspector, your local Flight 
Standards 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 the approval 
must specifically refer to this AD.

Related Information

    (i) For more information about this AD, contact Roger Durbin, 
Aerospace Engineer, Los Angeles ACO, Airframe Branch, ANM-120L, FAA 
Los Angeles Aircraft Certification Office, 3960 Paramount Blvd, 
Lakewood, CA 90712-4137; telephone: (562) 627-5233; fax: (562) 627-
5210; e-mail: roger.durbin@faa.gov.
    (j) 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, the FAA, 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 December 16, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-32207 Filed 12-22-10; 8:45 am]
BILLING CODE 4910-13-P


