[Federal Register Volume 76, Number 129 (Wednesday, July 6, 2011)]
[Rules and Regulations]
[Pages 39251-39254]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-15990]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-1203; Directorate Identifier 2010-NM-168-AD; 
Amendment 39-16738; AD 2011-14-03]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-
81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), and MD-88 
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 inspections for 
cracking of the left and right upper center skin panels of the 
horizontal stabilizer, and corrective action if necessary. 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 horizontal stabilizer upper 
center skin panel. Uncorrected cracks might ultimately lead to the loss 
of overall structural integrity of the horizontal stabilizer.

DATES: This AD is effective August 10, 2011.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of August 10, 
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; phone: 206-544-5000, extension 2; fax: 206-766-5683; e-mail: 
[email protected]; Internet https://www.myboeingfleet.com. You may 
review copies of the referenced

[[Page 39252]]

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 AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (phone: 800-647-5527) 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, 3960 Paramount Boulevard, Lakewood, California 90712-4137; 
phone: 562-627-5233; fax: 562-627-5210; e-mail: [email protected].

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 
December 23, 2010 (75 FR 80744). That NPRM proposed to require 
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, 
and replacing any cracked horizontal stabilizer upper center skin panel 
with a serviceable panel.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the proposal 
and the FAA's response to each comment.

Request To Clarify the Term ``Serviceable''

    Several commenters requested clarification of the term 
``serviceable.''
    American Airlines stated that the term ``serviceable'' applies to 
used and new aircraft parts. American commented that if a used skin 
plank that has been determined to be serviceable has been installed, 
then the part has accumulated fatigue damage and should be inspected 
using the repetitive method and the interval used prior to 
installation.
    Aeropostal Hangars stated that the word ``serviceable'' can be 
associated with ``removed in serviceable condition'' from another 
aircraft. The commenter stated that although the manufacturing 
tolerances of fastener holes allow the installation of a removed panel 
from one aircraft to another, it is not always possible considering 
oversized fasteners, etc. We infer that this commenter wants us to 
change paragraph (g)(2) of the NPRM to require replacement with a new, 
rather than serviceable, skin panel assembly.
    We agree to change paragraph (g)(2) in this final rule to require 
replacement with a new skin panel because it is not generally possible 
to install a used skin panel assembly due to the difficulty in matching 
drill holes and because the AD does not include a provision for 
identifying and tracking the accumulated time on the used part. We 
revised paragraph (g)(2) of this AD accordingly.

Request To Provide Options for Temporary Repairs

    Several commenters requested additional options for temporary 
repairs of certain crack configurations rather than replacement of skin 
panel assemblies before further flight.
    American Airlines stated that it has accomplished temporary 
cracking repairs on 21 airplanes based on the manufacturer's 
instructions and have not had any crack propagation from the repaired 
parts. American stated that doing a temporary repair results in the 
operation of a safe airplane, which can then be scheduled for permanent 
repair at a time that causes the least disruption for the airline and 
the flying public. This commenter requested that we allow temporary 
repairs to a cracked skin panel assembly.
    Delta Airlines presumed that skin panel cracks likely were caused 
by contributions from errors in removing or installing the skin panels 
because of the way the skin panels overlap. Some of Delta's cracked 
production skin panels were not adequately shimmed where cracks 
occurred. This commenter cited evidence that trim-out skin panel 
repairs would provide some reduction in stress concentration and allow 
skin panels to remain in service until a planned opportunity to change 
the panels occurs, which would reduce airplane out-of-service time. 
Delta stated that trim-out repairs should be allowed on skin panels and 
that the airplane should be allowed to stay in service until at least 
the next heavy maintenance visit.
    Aeropostal Hangars stated that the finding of a crack in an in-
service revenue aircraft that is not allowed temporary repairs could 
lead to a non-scheduled down time for the affected aircraft. We infer 
that this commenter wants us to allow temporary repairs.
    We disagree. We have determined that it will be difficult to 
evaluate the effect of all temporary repairs on safety, particularly 
since other temporary repairs allowed on the aft horizontal skin panel 
by AD 2007-10-04, Amendment 39-15045 (72 FR 25960, May 8, 2007), might 
already be present. We stated in the NPRM that a crack in the upper 
center skin panel might transfer the load to the upper aft skin panel, 
which might result in the upper aft skin panel cracking before reaching 
the existing inspection interval. Additionally, Aeropostal Hangars 
provided no data or information that would show that temporary repairs 
would provide an adequate level of safety.
    In this case, we have determined that the alternative method of 
compliance (AMOC) process is more appropriate for temporary repair 
approval. Under the provisions of paragraph (h) of this AD, we will 
consider requests for approval of an AMOC if sufficient data are 
submitted to substantiate that temporary repairs would provide an 
acceptable level of safety. Early field data indicate that 
substantially fewer center panel cracks than aft panel cracks will be 
detected; therefore, the AMOC process should not represent a 
substantial burden to operators. We have not changed this AD in this 
regard.

Request To Replace Horizontal Stabilizer

    Several commenters requested the option of replacing the whole 
horizontal stabilizer instead of replacing a cracked center skin panel 
because replacing the stabilizer would require only a few days of 
airplane out-of-service time instead of several weeks.
    We disagree. Horizontal stabilizer assemblies do not meet the 
criteria for serialized, rotable life-limited parts. Further, 
additional tracking information that is specific to a maintenance 
facility might be needed to ensure that inspections are occurring at 
the required times for swapped parts. However, under the provisions of 
paragraph (h) of this AD, we will consider requests for approval of an 
AMOC if sufficient data are submitted to substantiate that replacing 
the whole horizontal stabilizer

[[Page 39253]]

instead of replacing a cracked center skin panel would provide an 
acceptable level of safety. We have not changed this AD in this regard.

Request To Use Later Revisions of the Service Bulletin

    American Airlines requested that this proposed AD allow the use of 
later revisions of the service bulletin. American stated that allowing 
later versions would eliminate the need for AMOC approval for future 
service bulletin revisions.
    We disagree. We cannot use the phrase, ``or later FAA-approved 
revisions,'' in an AD when referring to the service document because 
doing so violates Office of the Federal Register (OFR) policies for 
approval of materials ``incorporated by reference.'' However, affected 
operators may request approval to use a later revision as an AMOC with 
this AD under the provisions of paragraph (h) of this AD. We have not 
changed this AD in this regard.

Explanation of Change to Applicability

    We have revised the applicability of this AD to identify The Boeing 
Company as the type certificate holder for the affected models.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
the AD with the changes described previously. We also determined that 
these changes will not increase the economic burden on any operator or 
increase the scope of the AD.

Costs of Compliance

    We estimate that this AD will affect 668 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this AD:

                                                                     Estimated Costs
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               Action                         Labor cost           Parts cost     Cost per product                   Cost on U.S. operators
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Inspection.........................  4 work-hours x $85 per hour           $0  $340 per inspection     $227,120 per inspection cycle.
                                      = $340 per inspection                     cycle.
                                      cycle.
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    We estimate the following costs to do any necessary repairs that 
would be required based on the results of the inspection. We have no 
way of determining the number of aircraft that might need these 
repairs.

                                               On-Condition Costs
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                                                                                                       Cost per
                    Action                                    Labor cost                 Parts cost    product
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Group 1: Skin panel replacement...............  648 work-hours x $85 per hour =             $36,405      $91,485
                                                 $55,080.
Group 2: Skin panel replacement...............  648 work-hours x $85 per hour =              54,071      109,151
                                                 $55,080.
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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

    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):

2011-14-03 The Boeing Company: Amendment 39-16738; Docket No. FAA-
2010-1203; Directorate Identifier 2010-NM-168-AD.

Effective Date

    (a) This AD is effective August 10, 2011.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all The Boeing Company Model DC-9-81 (MD-
81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87) and MD-88 
airplanes, certificated in any category.

Subject

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

[[Page 39254]]

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 horizontal stabilizer upper center skin panel. 
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 4,379 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 MD80-55A068, 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 MD80-55A068, 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 new skin panel, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin MD80-55A068, 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, 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 45, and the approval must specifically refer to this AD.

Related Information

    (i) For more information about this AD, contact Roger Durbin, 
Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles 
Aircraft Certification Office (ACO), 3960 Paramount Blvd., Lakewood, 
California 90712-4137; phone: 562-627-5233; fax: 562-627-5210; e-
mail: [email protected].

Material Incorporated by Reference

    (j) You must use Boeing Alert Service Bulletin MD80-55A068, 
dated July 16, 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 this service information 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; phone: 206-544-5000, extension 2; fax: 206-766-5683; e-mail: 
[email protected]; 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 425-227-1221.
    (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 202-741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington, on June 16, 2011.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-15990 Filed 7-5-11; 8:45 am]
BILLING CODE 4910-13-P