[Federal Register: December 6, 2007 (Volume 72, Number 234)]
[Proposed Rules]
[Page 68764-68766]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr06de07-11]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-0289; Directorate Identifier 2007-NM-208-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 757 Series 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 adopt a new airworthiness directive (AD)
for certain Boeing Model 757 series airplanes. This proposed AD would
require sealing the fasteners on the front and rear spars inside the
left and right main fuel tanks and on the lower panel of the center
fuel tank. This proposed AD would also require inspections of the wire
bundle support installations to verify if certain clamps are installed
and if Teflon sleeving covers the wire bundles inside the left and
right equipment cooling system bays, on the left and right rear spars,
and on the left and right front spars; and corrective actions if
necessary. This proposed AD results from a fuel system review conducted
by the manufacturer. We are proposing this AD to prevent improperly
sealed fasteners in the main and center fuel tanks from becoming an
ignition source, in the event of a fault current, which could result in
a fuel tank explosion and consequent loss of the airplane.
DATES: We must receive comments on this proposed AD by January 22,
2008.
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 AD, contact Boeing
Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.
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: Judy Coyle, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone
(425) 917-6497; fax (425) 917-6590.
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-2007-0289;
Directorate Identifier 2007-NM-208-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
[[Page 68765]]
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''
(66 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 a 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 proposed AD
are necessary to reduce the potential of ignition sources inside fuel
tanks, which, in combination with flammable fuel vapors, could result
in fuel tank explosions and consequent loss of the airplane.
Boeing has found that it is possible for some fuel tank fasteners,
in the event of a fault current, to become an ignition source on Boeing
Model 757 series airplanes. This condition, if not corrected, could
result in a fuel tank explosion and consequent loss of the airplane.
Relevant Service Information
We have reviewed Boeing Alert Service Bulletin 757-57A0064, dated
July 16, 2007. The service bulletin describes procedures for sealing
the fasteners on the front and rear spars inside the left and right
main fuel tanks and sealing the fasteners on the lower panel of the
center fuel tank. The service bulletin also describes procedures for
doing general visual inspections of the wire bundle support
installations to verify if certain full cushion clamps are installed
and to confirm if the wire bundles are covered in Teflon sleeving at
the following locations: Inside the left and right equipment cooling
system bays, on the left and right rear spars, and on the left and
right front spars. The service bulletin also describes procedures for
doing corrective actions if necessary, which include replacing any
incorrect clamps with certain full cushion clamps and installing any
missing Teflon sleeving. Accomplishing the actions specified in the
service information is intended to adequately address the unsafe
condition.
FAA's Determination and Requirements of the Proposed AD
We have evaluated all pertinent information and identified an
unsafe condition that is likely to exist or develop on other airplanes
of this same type design. For this reason, we are proposing this AD,
which would require accomplishing the actions specified in the service
information described previously, except as discussed under
``Difference between the Proposed AD and Service Bulletin.''
Difference Between the Proposed AD and Service Bulletin
The compliance table in paragraph 1.E. of the service bulletin
recommends accomplishing the corrective actions (clamp replacement and
installation of Teflon sleeving) within 5 years of the date on the
service bulletin. This AD, however, would require accomplishing the
corrective actions, if necessary, before further flight after
accomplishing the inspections. We have coordinated this difference with
Boeing.
Costs of Compliance
There are about 1,049 airplanes of the affected design in the
worldwide fleet. This proposed AD would affect about 539 airplanes of
U.S. registry. The proposed actions would take up to 545 work hours per
airplane depending on the airplane configuration, at an average labor
rate of $80 per work hour. Required parts would cost about $325 per
airplane. Based on these figures, the estimated cost of the proposed AD
for U.S. operators is up to $23,675,575, or up to $43,925 per airplane.
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
[[Page 68766]]
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, 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 Federal Aviation Administration (FAA) amends Sec. 39.13 by
adding the following new airworthiness directive (AD):
Boeing: Docket No. FAA-2007-0289; Directorate Identifier 2007-NM-
208-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by January
22, 2008.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 757-200, -200CB, -200PF, and
-300 series airplanes, certificated in any category; as identified
in Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007.
Unsafe Condition
(d) This AD results from a fuel system review conducted by the
manufacturer. We are issuing this AD to prevent improperly sealed
fasteners in the main and center fuel tanks from becoming an
ignition source, in the event of a fault current, which could result
in a fuel tank explosion and consequent loss of the airplane.
Compliance
(e) You are responsible for having the actions required by this
AD performed within the compliance times specified, unless the
actions have already been done.
Fastener Sealing and Inspections
(f) Within 60 months after the effective date of this AD, seal
the applicable fasteners and do the general visual inspections of
the wire bundle support installations, and do all the applicable
corrective actions before further flight, by accomplishing all of
the applicable actions specified in the Accomplishment Instructions
of Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007.
Alternative Methods of Compliance (AMOCs)
(g)(1) The Manager, Seattle Aircraft Certification Office, FAA,
has the authority to approve AMOCs for this AD, if requested in
accordance with the procedures found in 14 CFR 39.19.
(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 appropriate principal inspector (PI) in the FAA
Flight Standards District Office (FSDO), or lacking a PI, your local
FSDO.
Issued in Renton, Washington, on November 23, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-23639 Filed 12-5-07; 8:45 am]
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