[Federal Register Volume 76, Number 3 (Wednesday, January 5, 2011)]
[Rules and Regulations]
[Pages 430-432]
[FR Doc No: 2010-32993]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0953; Directorate Identifier 2010-NM-010-AD;
Amendment 39-16565; AD 2011-01-11]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Model MD-90-30
Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for the
products listed above. This AD requires repetitive high frequency eddy
current inspections for cracking on the hinge bearing lugs of the left
and right sides of the center section ribs of the horizontal
stabilizer, and related investigative and corrective actions if
necessary. This AD was prompted by reports of cracks found on either
the left or right (or in one case, both) sides of the center section
ribs of the horizontal stabilizer. We are issuing this AD to detect and
correct cracking in the hinge bearing lugs of the center section of the
left and right ribs, which could result in failure of the hinge bearing
lugs and consequent inability of the horizontal stabilizer to sustain
the required loads.

DATES: This AD is effective February 9, 2011.
    The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in the AD as of February 9,
2011.

ADDRESSES: 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<PHONE_NUMBER>, extension 2; fax<PHONE_NUMBER>; e-mail
<EMAIL_ADDRESS>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<PHONE_NUMBER>.

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 AD, the regulatory evaluation,
any comments received, and other information. The address for the
Docket Office (phone:<PHONE_NUMBER>) is Document Management Facility,
U.S. Department of Transportation, Docket Operations, M-30, West
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE.,
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Roger Durbin, Aerospace Engineer,
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification
Office (ACO), 3960 Paramount Boulevard, Lakewood, California 90712-
4137; telephone<PHONE_NUMBER>; fax<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to include an airworthiness directive (AD) that would apply to
the specified products. That NPRM published in the Federal Register on
October 1, 2010 (75 FR 60665). That NPRM proposed to require repetitive
high frequency eddy current inspections for cracking on the hinge
bearing lugs of the left and right sides of the center section ribs of
the horizontal stabilizer, and related investigative and corrective
actions if necessary.

Comments

    We gave the public the opportunity to participate in developing
this AD. We received no comments on the NPRM or on the determination of
the cost to the public.

Explanation of Change to Applicability

    We have revised the existing AD to identify model designations as
published in the most recent type certificate data sheet for the
affected models.

Conclusion

    We reviewed the relevant data and determined that air safety and
the public interest require adopting the AD as proposed--except for
minor editorial changes and the change described previously. We have
determined that these minor changes:
     Are consistent with the intent that was proposed in the
NPRM for correcting the unsafe condition; and
     Do not add any additional burden upon the public than was
already proposed in the NPRM.

Conclusion

    We reviewed the relevant data and determined that air safety and
the public interest require adopting the AD as proposed.

Interim Action

    We consider this AD interim action. The manufacturer is currently
developing a modification that will address the unsafe condition
identified in this AD. Once this modification is developed, approved,
and available, we might consider additional rulemaking.

Costs of Compliance

    We estimate that this AD affects 16 airplanes of U.S. registry. We
also estimate that it takes about 2 work-hours per product to comply
with this AD. The average labor rate is $85 per work-hour. Based on
these figures, we estimate the cost of this AD to the U.S. operators to
be $2,720, or $170 per product.

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

    This AD will not have federalism implications under Executive Order
13132. This AD will 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 that this AD:
    (1) Is not a ``significant regulatory action'' under Executive
Order 12866,
    (2) Is not a ``significant rule'' under 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.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator,
the FAA amends 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):

2011-01-11 The Boeing Company: Amendment 39-16565; Docket No. FAA-
2010-0953; Directorate Identifier 2010-NM-010-AD.

Effective Date

    (a) This AD is effective February 9, 2011.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all The Boeing Company 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 reports of cracks found on either the
left or right (or in one case, both) sides of the center section
ribs of the horizontal stabilizer. The Federal Aviation
Administration is issuing this AD to detect and correct cracking in
the hinge bearing lugs of the center section of the left and right
ribs, which could result in failure of the hinge bearing lugs and
consequent inability of the horizontal stabilizer to sustain the
required loads.

Compliance

    (f) You are responsible for having the actions required by this
AD performed within the compliance times specified, unless the
actions have already been done.

Repetitive Inspections and Corrective Actions for Cracking

    (g) At the applicable time in paragraph 1.E., ``Compliance,'' of
Boeing Alert Service Bulletin MD90-55A016, Revision 1, dated
February 17, 2010, except as required by paragraph (n) of this AD,
do a high frequency eddy current (HFEC) inspection for cracking on
the hinge bearing lugs of the left and right sides of the center
section ribs of the horizontal stabilizer, and do all applicable
related investigative actions, in accordance with the Accomplishment
Instructions of Boeing Alert Service Bulletin MD90-55A016, Revision
1, dated February 17, 2010. Do all applicable related investigative
actions before further flight.
    (h) If during any inspection required by paragraph (g) of this
AD, no cracking is found, repeat the inspection required by
paragraph (g) of this AD thereafter at intervals not to exceed 1,680
flight cycles.
    (i) If during any inspection required by paragraph (g) or (h) of
this AD, any crack is found having a length between Points `A' and
`B' less than or equal to 0.15 inch and crack length between Points
`C' and `D' less than or equal to 0.05 inch, as identified in Boeing
Alert Service Bulletin MD90-55A016, Revision 1, dated February 17,
2010: Before further flight, blend out the crack; and within

1,000 flight cycles after doing the blend out, do an HFEC inspection
of the blend out on the center section rib hinge bearing lug; in
accordance with the Accomplishment Instructions of Boeing Alert
Service Bulletin MD90-55A016, Revision 1, dated February 17, 2010.
Repeat the HFEC inspection of the blend out thereafter at intervals
not to exceed 400 flight cycles until the replacement specified by
paragraph (j) is done.
    (j) If any cracking is detected during any inspection required
by paragraph (i) of this AD, before further flight, replace the
horizontal stabilizer center section rib with a new horizontal
stabilizer center section rib, in accordance with the Accomplishment
Instructions of Boeing Alert Service Bulletin MD90-55A016, Revision
1, dated February 17, 2010.
    (k) If during any inspection required by paragraph (g) or (h) of
this AD, any crack is found having a length between Points `A' and
`B' greater than 0.15 inch or crack length between Points `C' and
`D' greater than 0.05 inch, as identified in Boeing Alert Service
Bulletin MD90-55A016, Revision 1, dated February 17, 2010: Before
further flight, replace the horizontal stabilizer center section rib
with a new horizontal stabilizer center section rib, in accordance
with the Accomplishment Instructions of Boeing Alert Service
Bulletin MD90-55A016, Revision 1, dated February 17, 2010.
    (l) For any airplane having a horizontal stabilizer center
section rib replaced during the actions required by paragraph (j) or
(k) of this AD: Before the accumulation of 7,200 total flight cycles
on the new horizontal stabilizer center section rib, do the actions
required by paragraph (g) of this AD, and do all applicable actions
specified in paragraphs (h), (i), (j), and (k) of this AD.

Credit for Actions Accomplished According to Previous Issue of Service
Bulletin

    (m) Actions accomplished before the effective date of this AD
according to Boeing Alert Service Bulletin MD90-55A016, dated
December 16, 2009, are considered acceptable for compliance with the
corresponding actions required by paragraphs (g), (h), (i), (j), and
(k) of this AD.

Exception to the Service Bulletin

    (n) Where Boeing Alert Service Bulletin MD90-55A016, Revision 1,
dated February 17, 2010, specifies a compliance time ``after the
original issue date on the service bulletin,'' this AD requires
compliance within the specified compliance time after the effective
date of this AD.

Alternative Methods of Compliance (AMOCs)

    (o)(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. Send
information to ATTN: Roger Durbin, Aerospace Engineer, Airframe
Branch, ANM-120L, FAA, Los Angeles ACO, 3960 Paramount Boulevard,
Lakewood, California 90712-4137; telephone<PHONE_NUMBER>; fax (562)
627-5210.
    (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, or lacking a
principal inspector, your local Flight Standards District Office.
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 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

    (p) For more information about this AD, contact Roger Durbin,
Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles ACO,
3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone
(562) 627-5233; fax<PHONE_NUMBER>.

Material Incorporated by Reference

    (q) You must use Boeing Alert Service Bulletin MD90-55A016,
Revision 1, dated February 17, 2010, to do the actions required by
this AD, unless the AD specifies otherwise.
    (1) The Director of the Federal Register approved the
incorporation by reference of Boeing Alert Service Bulletin MD90-
55A016, Revision 1, dated February 17, 2010, under 5 U.S.C. 552(a)
and 1 CFR part 51.
    (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<PHONE_NUMBER>, extension 2; fax<PHONE_NUMBER>; e-mail
<EMAIL_ADDRESS>Internet https://www.myboeingfleet.com.
    (3) You may review copies of the 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<PHONE_NUMBER>.
    (4) You may also review copies of the service information that
is incorporated by reference at the National Archives and Records
Administration (NARA). For information on the availability of this
material at an NARA facility, call<PHONE_NUMBER>, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington, on December 22, 2010.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2010-32993 Filed 1-4-11; 8:45 am]
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