
[Federal Register Volume 76, Number 49 (Monday, March 14, 2011)]
[Proposed Rules]
[Pages 13546-13549]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-5726]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0218; Directorate Identifier 2010-NM-164-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company 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 the 
products listed above. This proposed AD would require a detailed 
inspection to detect distress and existing repairs to the leading edge 
structure of the vertical stabilizer at the splice at Station 
Zfs=52.267; repetitive inspections for cracking in the front spar cap 
forward flanges of the vertical stabilizer, and either the aft flanges 
or side skins; repetitive inspections for loose and missing fasteners; 
and related investigative and corrective actions if necessary. This 
proposed AD was prompted by reports of cracked vertical stabilizer 
skin, a severed front spar cap, elongated fastener holes at the leading 
edge of the vertical stabilizer, and a cracked front spar web and front 
spar cap bolt holes in the vertical stabilizer. We are proposing this 
AD to detect and correct such cracking damage, which could result in 
the structure being unable to support limit load, and could lead to the 
loss of the vertical stabilizer.

DATES: We must receive comments on this proposed AD by April 28, 2011.

ADDRESSES: You may send comments by any of the following methods:
     Federal Rulemaking 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; phone: 206-544-5000, extension 2; fax: 206-766-5683; e-mail:

[[Page 13547]]

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, 
Airframe Branch, ANM-120L, Los Angeles ACO, 3960 Paramount Blvd., 
Lakewood, CA 90712-4137; phone: 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-2011-0218; 
Directorate Identifier 2010-NM-164-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 elongated fastener holes at the 
leading edge of the vertical stabilizer at station Zfs=52.267. The 
affected Model MD-90 airplane had accrued 15,555 total flight hours and 
14,310 total landing cycles when the elongated fastener holes were 
found. Additionally, we have received two reports of Model MD-80 
airplanes with cracked vertical stabilizer skin at station Zfs=52.267. 
Subsequent inspection revealed a severed front spar cap and a cracked 
front spar web. The affected Model MD-80 airplanes had accrued between 
39,749 and 56,212 total flight hours and between 32,176 and 44,001 
total landing cycles when the cracks/anomalies were found. Cracks were 
also found on several other Model MD-80 airplanes in the vertical 
stabilizer front spar cap bolt holes. The cause of the fastener damage, 
elongated fastener holes, and skin cracks is high loading occurrences, 
such as, but not limited to, in-flight turbulence. Cracks in the 
vertical stabilizer leading edge and front spar cap could result in the 
structure being unable to support limit load, and could lead to the 
loss of the vertical stabilizer.

Related Rulemaking

    We are considering similar rulemaking for 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. The Model MD-90 airplane vertical stabilizer is 
similar in design and loading to that of the Model MD-80 airplane 
vertical stabilizer.

Relevant Service Information

    We reviewed Boeing Alert Service Bulletin MD90-55A014, dated June 
24, 2010. The service information describes procedures for a detailed 
inspection to detect distress in, and existing repairs to the leading 
edge structure of the vertical stabilizer at the splice at Station 
Zfs=52.267, and corrective action if necessary. The corrective action 
is doing a leading edge repair, if the leading edge is distressed, by 
repairing or replacing the leading edge splice band of the vertical 
stabilizer. The service information defines ``distress'' as deformed 
holes, elongated holes, oversized holes or cracks in the leading edge 
skin and splice; and ``existing repairs'' as bushings, washers or 
reinforcing repairs to the leading edge.
    The service information also describes procedures for repetitive 
inspections for cracking in the front spar cap of the vertical 
stabilizer using the inspections specified in Option 1 or Option 2 of 
the service information, and related investigative and corrective 
actions if necessary.
    Option 1 involves an open hole eddy current high frequency (ETHF) 
inspection of the forward flanges and a radiographic testing inspection 
of the aft flanges; Option 2 involves an open hole ETHF inspection of 
the forward flanges and an ETHF surface inspection of the side skins of 
the aft flanges. For airplanes on which any cracking is found, the 
related investigative action is confirming the cracking through a 
specified evaluation/verification process. The corrective action is 
contacting Boeing and doing the repair in accordance with Boeing's 
instructions.
    The service information also describes procedures for repetitive 
detailed inspections for indications of loose and missing fasteners of 
the leading edge structure of the vertical stabilizer at the splice at 
Station Zfs=52.267, and corrective actions if necessary. The corrective 
action, if any loose or missing fasteners are found, is repairing the 
leading edge by repairing or replacing the leading edge splice band of 
the vertical stabilizer.

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 designs.

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 will affect 19 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

[[Page 13548]]



                                                 Estimated Costs
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                                                                                                Cost on U.S.
              Action                    Labor cost        Parts cost    Cost per product          operators
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Inspection for existing repairs,   10 work-hours x $85            $0  $850................  $16,150.
 distress.                          per hour = $850.
Repetitive inspections for         7 work-hours x $85             $0  $595 per inspection   $11,305 per
 cracking and loose and missing     per hour = $595 per                cycle.                inspection cycle.
 fasteners.                         inspection cycle.
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    We have received no definitive data that would enable us to provide 
cost estimates for the on-condition action 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-2011-0218; Directorate Identifier 
2010-NM-164-AD.

Comments Due Date

    (a) We must receive comments by April 28, 2011.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to The Boeing Company Model MD-90-30 
airplanes, certificated in any category, as identified in Boeing 
Alert Service Bulletin MD90-55A014, dated June 24, 2010.

Subject

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

Unsafe Condition

    (e) This AD was prompted by reports of cracked vertical 
stabilizer skin, a severed front spar cap, elongated fastener holes 
at the leading edge of the vertical stabilizer, and a cracked front 
spar web and front spar cap bolt holes in the vertical stabilizer. 
We are issuing this AD to detect and correct such cracking damage, 
which could result in the structure being unable to support limit 
load, and could lead to the loss of the vertical stabilizer.

Compliance

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

Inspections for Distress/Repairs

    (g) Within 4,100 flight cycles after the effective date of this 
AD, do a detailed inspection for distress in and existing repairs to 
the leading edge structure of the vertical stabilizer at the splice 
at Station Zfs=52.267, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin MD90-55A014, dated 
June 24, 2010.

Repetitive Inspections for Cracks, and Related Investigative and 
Corrective Actions

    (h) Before further flight after doing the inspection required by 
paragraph (g) of this AD, inspect for cracks of the left and right 
vertical stabilizer front spar cap, in accordance with either Option 
1 or Option 2 as specified in the Accomplishment Instructions of 
Boeing Alert Service Bulletin MD90-55A014, dated June 24, 2010. If 
any crack is found, before further flight, evaluate and verify to 
confirm all crack indications, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin MD90-55A014, dated 
June 24, 2010.
    (1) If any cracking is confirmed, before further flight, repair 
using a method approved in accordance with the procedures specified 
in paragraph (l) of this AD.
    (2) If no cracking is confirmed, repeat the inspection 
thereafter at intervals not to exceed the applicable interval 
specified in paragraph (h)(2)(i) or (h)(2)(ii) of this AD.
    (i) If the most recent inspection was done using Option 1, the 
next inspection must be done within 4,400 flight cycles.
    (ii) If the most recent inspection was done using Option 2, the 
next inspection must be done within 3,000 flight cycles.

Leading Edge Repair

    (i) If leading edge distress is found during the detailed 
inspection required by paragraph (g) of this AD, before further 
flight and after accomplishing the inspection required by paragraph 
(h) of this AD, repair the leading edge, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin MD90-
55A014, dated June 24, 2010.

Inspection for Loose/Missing Fasteners

    (j) For airplanes on which no cracking is confirmed during the 
initial inspection required by paragraph (h) of this AD: At the 
applicable time specified in paragraph (j)(1) or (j)(2) of this AD, 
do a detailed inspection for indications of loose and missing 
fasteners, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin MD90-55A014, dated June 24, 2010. If 
any loose or missing fastener is found, before further flight, 
repair the leading edge, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin MD90-55A014, dated 
June 24, 2010.
    (1) If the inspection required by paragraph (h) was done using 
Option 1, do the inspection required by paragraph (j) of this AD 
within 4,400 flight cycles after accomplishing the inspection 
required by paragraph (h) of this AD.

[[Page 13549]]

    (2) If inspection required by paragraph (h) was done using 
Option 2, do the inspection required by paragraph (j) of this AD 
within 3,000 flight cycles after accomplishing the inspection 
required by paragraph (h) of this AD.
    (k) For airplanes on which no cracking is confirmed during the 
most recent inspection required by paragraph (h) of this AD: Repeat 
the inspection for loose and missing fasteners required by paragraph 
(j) of this AD thereafter at intervals not to exceed the applicable 
time specified in paragraph (k)(1) or (k)(2) of this AD.
    (1) If the most recent inspection required by paragraph (h) was 
done using Option 1, the next inspection required by paragraph (j) 
of this AD must be done within 4,400 flight cycles after 
accomplishing the most recent inspection required by paragraph (j) 
of this AD.
    (2) If the most recent inspection required by paragraph (h) was 
done using Option 2, the next inspection required by paragraph (j) 
of this AD must be done within 3,000 flight cycles after the most 
recent inspection required by paragraph (j) of this AD.

Alternative Methods of Compliance (AMOCs)

    (l)(1) The Manager, Los Angeles Aircraft Certification Office, 
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 the approval 
must specifically refer to this AD.

Related Information

    (m) For more information about this AD, contact Roger Durbin, 
Aerospace Engineer, Airframe Branch, ANM-120L, Los Angeles ACO, 3960 
Paramount Blvd., Lakewood, CA 90712-4137; phone: 562-627-5233; fax: 
562-627-5210; e-mail: Roger.Durbin@faa.gov.
    (n) 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: 
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 March 4, 2011.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-5726 Filed 3-11-11; 8:45 am]
BILLING CODE 4910-13-P


