[Federal Register: March 10, 2009 (Volume 74, Number 45)]
[Proposed Rules]
[Page 10202-10204]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr10mr09-19]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2009-0213; Directorate Identifier 2008-NM-224-AD]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas 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
certain McDonnell Douglas Model MD-90-30 airplanes. This proposed AD
would require installing fuses and wire protection in certain wing and
fuel tank spars. This proposed AD results from fuel system reviews
conducted by the manufacturer. We are proposing this AD to prevent
possible damage to the fuel level float or pressure switch wires. Such
damage could become a potential ignition source inside the fuel tank,
and, combined with flammable fuel vapors, could result in a fuel tank
explosion and consequent loss of the airplane.
[[Page 10203]]
DATES: We must receive comments on this proposed AD by April 24, 2009.
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 or 425-227-1152.
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: Samuel Lee, Aerospace Engineer,
Propulsion Branch, ANM-140L, FAA, Los Angeles Aircraft Certification
Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137;
telephone (562) 627-5262; 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-2009-0213;
Directorate Identifier 2008-NM-224-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
The FAA has examined the underlying safety issues involved in fuel
tank explosions on several large transport airplanes, including the
adequacy of existing regulations, the service history of airplanes
subject to those regulations, and existing maintenance practices for
fuel tank systems. As a result of those findings, we issued a
regulation titled ``Transport Airplane Fuel Tank System Design Review,
Flammability Reduction and Maintenance and Inspection Requirements''
(67 FR 23086, May 7, 2001). In addition to new airworthiness standards
for transport airplanes and new maintenance requirements, this rule
included Special Federal Aviation Regulation No. 88 (``SFAR 88,''
Amendment 21-78, and subsequent Amendments 21-82 and 21-83).
Among other actions, SFAR 88 requires certain type design (i.e.,
type certificate (TC) and supplemental type certificate (STC)) holders
to substantiate that their fuel tank systems can prevent ignition
sources in the fuel tanks. This requirement applies to type design
holders for large turbine-powered transport airplanes and for
subsequent modifications to those airplanes. It requires them to
perform design reviews and to develop design changes and maintenance
procedures if their designs do not meet the new fuel tank safety
standards. As explained in the preamble to the rule, we intended to
adopt airworthiness directives to mandate any changes found necessary
to address unsafe conditions identified as a result of these reviews.
In evaluating these design reviews, we have established four
criteria intended to define the unsafe conditions associated with fuel
tank systems that require corrective actions. The percentage of
operating time during which fuel tanks are exposed to flammable
conditions is one of these criteria. The other three criteria address
the failure types under evaluation: single failures, single failures in
combination with another latent condition(s), and in-service failure
experience. For all four criteria, the evaluations included
consideration of previous actions taken that may mitigate the need for
further action.
We have determined that the actions identified in this AD are
necessary to reduce the potential of ignition sources inside fuel
tanks, which, in combination with flammable fuel vapors, could result
in a fuel tank explosion and consequent loss of the airplane.
We have received a report that fuel level float switch wires
located on the left and right wing forward spar, center fuel tank
forward spar and forward auxiliary fuel tank, and pressure switch wires
located on the center fuel tank forward spar are routed in the same
bundles as power wires. If a short circuit between a fuel level float
or pressure switch wire and a power wire occurs, an over current can
cause excessive temperatures in the fuel level float or pressure switch
wires, resulting in damage and becoming a potential ignition source.
This condition, if not corrected, could result in possible damage to
the fuel level float or pressure switch wires, and become a potential
ignition source for the fuel tank.
Relevant Service Information
We have reviewed Boeing Service Bulletin MD90-28-012, dated
November 19, 2008. The service bulletin describes procedures for
installing fuses and wire protection in certain wing and fuel tank
spars. For Group 1, the service bulletin describes procedures for
installing fuel level float switch in-line fuses and wire protection in
the left and right wing forward spars and center fuel tank forward
spar, right side. For Group 2, the service bulletin describes
procedures for installing fuel level float switch in-line fuses and
wire protection in the left and right wing forward spars, center fuel
tank forward spar, right side, and forward auxiliary fuel tank, right
side; and installing a fuel pressure switch in-line fuse and wire
protection in the center fuel tank forward spar, left side.
FAA's Determination and Requirements of This Proposed AD
We are proposing this AD because we evaluated all relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the(se) same type
design(s). This proposed AD would require accomplishing the
[[Page 10204]]
actions specified in the service information described previously.
Costs of Compliance
We estimate that this proposed AD would affect 15 airplanes of U.S.
registry. The following table provides the estimated costs for U.S.
operators to comply with this proposed AD.
Table--Estimated Costs
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Number of U.S.-
Action Work hours Average labor Parts Cost per product registered Fleet cost
rate per hour airplanes
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Installation, depending on Group. 20 or 26............ $80 $1,132 or $1,822... $2,732 or $3,902... 15 $40,980 to $58,530.
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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 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), 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.
You can find our regulatory evaluation and the estimated costs of
compliance in the AD Docket.
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 AD:
McDonnell Douglas: Docket No. FAA-2009-0213; Directorate Identifier
2008-NM-224-AD.
Comments Due Date
(a) We must receive comments by April 24, 2009.
Affected ADs
(b) None.
Applicability
(c) This AD applies to McDonnell Douglas Model MD-90-30
airplanes, certificated in any category, excluding fuselage number
2159.
Subject
(d) Air Transport Association (ATA) of America Code 28: Fuel.
Unsafe Condition
(e) This AD results from fuel system reviews conducted by the
manufacturer. We are issuing this AD to prevent possible damage to
the fuel level float or pressure switch wires. Such damage could
become a potential ignition source inside the fuel tank, and, when
combined with flammable fuel vapors, could result in a fuel tank
explosion and consequent loss of 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.
Installation
(g) Within 5 years after the effective date of this AD, do the
actions specified in paragraph (g)(1) or (g)(2) of this AD, as
applicable, in accordance with the Accomplishment Instructions of
Boeing Service Bulletin MD90-28-012, dated November 19, 2008 (``the
service bulletin'').
(1) For Group 1 airplanes identified in the service bulletin,
install fuel level float switch in-line fuses and wire protection in
the left and right wing forward spars and center fuel tank forward
spar, right side.
(2) For Group 2 airplanes identified in the service bulletin,
install fuel level float switch in-line fuses and wire protection in
the left and right wing forward spars, center fuel tank forward
spar, right side, and forward auxiliary fuel tank, right side; and
install a fuel pressure switch in-line fuse and wire protection in
the center fuel tank forward spar, left side.
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. Send
information to Attn: Samuel Lee, Aerospace Engineer, Propulsion
Branch, ANM-140L, FAA, Los Angeles Aircraft Certification Office,
3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone
(562) 627-5262; 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.
Issued in Renton, Washington, on February 27, 2009.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E9-5014 Filed 3-9-09; 8:45 am]
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