
[Federal Register: July 1, 2010 (Volume 75, Number 126)]
[Proposed Rules]               
[Page 38056-38058]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr01jy10-24]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0645; Directorate Identifier 2009-NM-200-AD]
RIN 2120-AA64

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

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede an existing airworthiness 
directive (AD) that applies to certain Model MD-90-30 airplanes. The 
existing AD currently requires a detailed inspection for certain 
defects of the upper fasteners of the aft mount support fittings of the 
left and right engines, and corrective actions if necessary. This 
proposed AD would instead require repetitive replacement of the upper 
row of fasteners of the support fittings of the engine aft mount with 
new fasteners; and perform repetitive general visual inspections for 
defects of the lower row fasteners (Row B) of the support fittings of 
the left and right engine aft mounts, and replacement of all clearance 
fit fasteners in the lower row if necessary. This proposed AD results 
from reports of loose, cracked, or missing fasteners in the aft mount 
support fitting of the left and right engines. We are proposing this AD 
to prevent loose, cracked, or missing fasteners in the engine aft mount 
support fittings, which could lead to separation of the support 
fittings from the pylon, and could result in separation of the engine 
from the airplane.

DATES: We must receive comments on this proposed AD by August 16, 2010.

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 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 (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-2010-0645; 
Directorate Identifier 2009-NM-200-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

    On August 25, 2008, we issued AD 2008-18-10, Amendment 39-15667 (73 
FR 52203, September 9, 2008), for certain McDonnell Douglas Corporation 
Model MD-90-30 airplanes. That AD requires a detailed inspection for 
certain defects of the upper fasteners of the aft mount support 
fittings of the left and right engines, and corrective actions if 
necessary. That AD resulted from reports of loose, cracked, or missing 
fasteners in the aft mount support fittings of the left and right 
engines. We issued that AD to detect and correct loose, cracked, or 
missing fasteners in the engine aft support mount fittings, which could 
lead to separation of the support fittings from the pylon, and could 
result in separation of the engine from the airplane.

Actions Since Existing AD Was Issued

    The preamble to AD 2008-18-10 explains that we considered the 
requirements ``interim action'' and were considering further 
rulemaking. We now have determined that further rulemaking is indeed 
necessary, and this proposed AD follows from that determination.
    We also have received additional reports of loose, cracked, or 
missing fasteners in the aft mount support fitting of the left and 
right engines on 29 McDonnell Douglas Corporation Model MD-90-30 
airplanes. The airplanes had accumulated between 15,560 and 37,298 
total flight hours, and between 13,995 and 31,294 total flight cycles.
    Results of a safety assessment of the missing fasteners indicate 
that loose or otherwise discrepant fasteners in the top horizontal row, 
common with the pylon skin, significantly decrease the margin of safety 
of the aft mount support installation at the design limit load. 
Replacement of the upper row of fasteners at new specified intervals 
will help minimize the possibility of these fasteners becoming an 
unsafe condition while in service. Inspection of the lower

[[Page 38057]]

row of fasteners will help ensure design integrity.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin MD90-54A003, 
Revision 2, dated February 12, 2010. The service bulletin describes 
procedures for repetitive replacement of the upper row of fasteners 
(Row A) of the support fittings of the left and right engine aft mount 
with new fasteners.
    The service bulletin also describes procedures for repetitive 
general visual inspections for defects of the lower row fasteners (Row 
B) of the support fittings of the left and right engine aft mounts 
(that includes a gap check under the head or nut, and a torque check), 
as necessary for defects of the lower row of fasteners (Row B) of the 
support fittings of the left and right engine aft mounts, and replacing 
all clearance fit fasteners in the lower row (Row B) with new fasteners 
if any defect is found. Defects include missing, loose, and damaged 
fasteners.
    The service bulletin specifies the compliance times for the initial 
replacement and inspections as follows:
     For Configurations 1 and 3 airplanes, as identified in the 
service bulletin: Within 10,000 flight cycles after fastener 
replacement in accordance with Boeing Service Bulletin MD90-54A002 or 
Boeing Multiple Operator Message 1-893882781-2, dated July 25, 2008.
     For Configurations 2 and 4 airplanes, as identified in the 
service bulletin: Within 2,457 flight cycles after the original issue 
date on the service bulletin (August 10, 2009).
    The repetitive interval for replacement and inspections is not to 
exceed 10,000 flight cycles.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to develop on other airplanes of the 
same type design. For this reason, we are proposing this AD, which 
would supersede AD 2008-18-10. This proposed AD would not retain the 
requirements of AD 2008-18-10. This proposed AD would require 
accomplishing the actions specified in the service information 
described previously.

Costs of Compliance

    There are about 107 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD.

                                                                     Estimated Costs
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                                                                                                                   Number of U.S.-
               Action                  Work hours     Average labor          Parts            Cost per airplane      registered          Fleet cost
                                                      rate per hour                                                   airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Replacement........................              14             $85  $152 per replacement.  $1,342 per                         13  $17,446 per
                                                                                             replacement cycle.                     replacement cycle.
Inspections........................               4              85  $0...................  $340 per inspection                13  $4,420 per inspection
                                                                                             cycle.                                 cycle.
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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

    We have 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 that the 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD and placed it in the AD docket. See the 
ADDRESSES section for a location to examine the regulatory evaluation.

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 removing Amendment 39-15667 (73 FR 
52203, September 9, 2008) and adding the following new AD:

McDonnell Douglas Corporation: Docket No. FAA-2010-0645; Directorate 
Identifier 2009-NM-200-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by August 
16, 2010.

Affected ADs

    (b) This AD supersedes AD 2008-18-10, Amendment 39-15667.

Applicability

    (c) This AD applies to McDonnell Douglas Corporation Model MD-
90-30 airplanes, certificated in any category, as identified in 
Boeing Alert Service Bulletin MD90-54A003, Revision 2, dated 
February 12, 2010.

Subject

    (d) Air Transport Association (ATA) of America Code 54: 
Nacelles/Pylons.

[[Page 38058]]

Unsafe Condition

    (e) This AD results from reports of loose, cracked, or missing 
fasteners in the aft mount support fitting of the left and right 
engines. The Federal Aviation Administration is issuing this AD to 
prevent loose, cracked, or missing fasteners in the engine aft 
support mount fitting, which could lead to separation of the support 
fitting from the pylon, and could result in separation of the engine 
from the airplane.

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.

Replacement and Inspection

    (g) Except as required by paragraph (i) of this AD, at the 
applicable time specified in paragraph 1.E. ``Compliance'' of Boeing 
Alert Service Bulletin MD90-54A003, Revision 2, dated February 12, 
2010: Replace the upper row of fasteners (Row A) of the support 
fittings of the left and right engine aft mounts with new fasteners, 
in accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin MD90-54A003, Revision 2, dated February 12, 2010. 
Repeat the replacement thereafter at intervals not to exceed 10,000 
flight cycles.
    (h) Concurrently with any replacement required by paragraph (g) 
of this AD: Perform a general visual inspection for defects of the 
lower row fasteners (Row B) of the support fittings of the left and 
right engine aft mounts, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin MD90-54A003, Revision 
2, dated February 12, 2010. Defects include missing, loose, and 
damaged fasteners.
    (1) If no defect is found during any general visual inspection 
required by paragraph (h) of this AD, before further flight, insert 
a 0.0015-inch feeler gauge between the washer and the structure, or 
between the fastener head and structure, as applicable, to detect a 
gap condition, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin MD90-54A003, Revision 2, dated 
February 12, 2010. A gap condition is a defect identified in any 
location where the feeler gauge can slip completely between a washer 
or a fastener head and the structure.
    (i) If no defect is found during any gap check required by 
paragraph (h)(1) of this AD, before further flight, apply torque to 
the fasteners of the lower row (Row B) to determine if there is a 
defect, in accordance with the Accomplishment Instructions of Boeing 
Alert Service Bulletin MD90-54A003, Revision 2, dated February 12, 
2010. A defect is any fastener that turns with the application of 
the specified torque. If any defect is found, before further flight, 
replace all clearance fit fasteners in the lower row (Row B), in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin MD90-54A003, Revision 2, dated February 12, 2010.
    (ii) If any defect is found during any gap check required by 
paragraph (h)(1) of this AD, before further flight, replace all 
clearance fit fasteners in the lower row (Row B), in accordance with 
the Accomplishment Instructions of Boeing Alert Service Bulletin 
MD90-54A003, Revision 2, dated February 12, 2010.
    (2) If any defect is found during any general visual inspection 
required by paragraph (h) of this AD, before further flight, replace 
all clearance fit fasteners in the lower row (Row B), in accordance 
with the Accomplishment Instructions of Boeing Alert Service 
Bulletin MD90-54A003, Revision 2, dated February 12, 2010.

Exception to Service Bulletin Compliance Times

    (i) Where Boeing Alert Service Bulletin MD90-54A003, Revision 2, 
dated February 12, 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.

Credit for Actions Accomplished in Accordance With Previous Service 
Information

    (j) Replacements and inspections accomplished before the 
effective date of this AD in accordance with Boeing Alert Service 
Bulletin MD90-54A003, Revision 1, dated November 17, 2009, are 
considered acceptable for compliance with the corresponding actions 
required by this AD.

Alternative Methods of Compliance (AMOCs)

    (k)(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 (562) 627-5233; 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 14 CFR 25.571, 
Amendment 45, and the approval must specifically refer to this AD.

    Issued in Renton, Washington, on June 23, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-15988 Filed 6-30-10; 8:45 am]
BILLING CODE 4910-13-P

