[Federal Register: April 30, 2007 (Volume 72, Number 82)]
[Proposed Rules]
[Page 21166-21169]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr30ap07-22]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-28035; Directorate Identifier 2006-NM-293-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 767 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 767 airplanes. This proposed AD would require
sealing certain fasteners and stiffeners in the fuel tank, and changing
certain wire bundle clamp configurations on the fuel
[[Page 21167]]
tank walls. This proposed AD results from fuel system reviews conducted
by the manufacturer. We are proposing this AD to prevent possible
ignition sources in the auxiliary fuel tank, main fuel tanks, and surge
tanks caused by a wiring short or lightning strike, which could result
in fuel tank explosions and consequent loss of the airplane.
DATES: We must receive comments on this proposed AD by June 14, 2007.
ADDRESSES: Use one of the following addresses to submit comments on
this proposed AD.
DOT Docket Web site: Go to http://dms.dot.gov and follow
the instructions for sending your comments electronically.
Government-wide rulemaking Web site: Go to http://www.regulations.gov
and follow the instructions for sending your
comments electronically.
Mail: Docket Management Facility, U.S. Department of
Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401,
Washington, DC 20590.
Fax: (202) 493-2251.
Hand Delivery: Room PL-401 on the plaza level of the
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle,
Washington 98124-2207, for the service information identified in this
proposed AD.
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 submit any relevant written data, views, or
arguments regarding this proposed AD. Send your comments to an address
listed in the ADDRESSES section. Include the docket number ``FAA-2007-
28035; Directorate Identifier 2006-NM-293-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of the proposed AD. We will
consider all comments received by the closing date and may amend the
proposed AD in light of those comments.
We will post all comments we receive, without change, to http://dms.dot.gov
, including any personal information you provide. We will
also post a report summarizing each substantive verbal contact with FAA
personnel concerning this proposed AD. Using the search function of
that web site, anyone can find and read the comments in any of our
dockets, including the name of the individual who sent the comment (or
signed the comment on behalf of an association, business, labor union,
etc.). You may review DOT's complete Privacy Act Statement in the
Federal Register published on April 11, 2000 (65 FR 19477-78), or you
may visit http://dms.dot.gov.
Examining the Docket
You may examine the AD docket on the Internet at http://dms.dot.gov
, or in person at the Docket Management Facility office
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT
street address stated in the ADDRESSES section. Comments will be
available in the AD docket shortly after the Docket Management System
receives them.
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 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.
A safety assessment by Boeing identified a certain fastener type in
the fuel tank walls that has an insufficient bond to the structure.
These fasteners can be a path for electrical energy to enter the fuel
tank if a wiring short occurs in a wire bundle installed along the fuel
tank boundary structure, or if lightning strikes a wing surface. If
energy from a wiring short or lightning strike goes through these
fasteners, arcing can occur at the ends of the fasteners in the fuel
tank. The ends of the fasteners in the fuel tank do not have sufficient
electrical insulation to contain the energy from the arcs. This
condition, if not corrected, could result in a potential ignition
source inside a fuel tank.
Relevant Service Information
We have reviewed Boeing Alert Service Bulletin 767-57A0100, dated
August 21, 2006. The service bulletin describes procedures for sealing
the ends of the fasteners on the brackets that hold the vortex
generators, and, for certain airplanes, sealing the ends of fasteners
on certain stiffeners on the rear spar.
We have also reviewed Boeing Alert Service Bulletin 767-57A0102,
dated October 25, 2006. The service bulletin describes procedures for
changing the wire bundle clamp configurations at specified locations on
the fuel tank walls, and sealing the fasteners and certain stiffeners
at specified locations in the fuel tank.
Accomplishing the actions specified in the service information is
intended to adequately address the unsafe condition.
[[Page 21168]]
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.
Costs of Compliance
There are about 925 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. There are no U.S.-
registered airplanes in Group 3 of Service Bulletin 767-57A0102. The
average labor rate is $80 per work hour.
Estimated Costs
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Number of
Cost per U.S.-
Service bulletin Group Work hours Parts airplane registered Fleet cost
airplanes
----------------------------------------------------------------------------------------------------------------
767-57A0100....................... 1 6 (\1\) $480 341 $163,680
2 114 (\1\) 9,120 21 191,520
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767-57A0102....................... 1 246 $1,632 21,312 341 7,267,392
2 874 1,304 71,224 21 1,495,704
3 24 338 2,258 0 0
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(1) Minimal.
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, 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-2007-28035; Directorate Identifier 2006-NM-
293-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by June 14,
2007.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Model 767-200, -300, -300F, and -400ER
series airplanes; certificated in any category; as identified in
Boeing Alert Service Bulletin 767-57A0100, dated August 21, 2006;
and Boeing Alert Service Bulletin 767-57A0102, dated October 25,
2006.
Unsafe Condition
(d) This AD results from fuel system reviews conducted by the
manufacturer. We are issuing this AD to prevent possible ignition
sources in the auxiliary fuel tank, main fuel tanks, and surge tanks
caused by a wiring short or lightning strike, which could result in
fuel tank explosions 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 Sealant Application
(f) For airplanes identified in Boeing Alert Service Bulletin
767-57A0100, dated August 21, 2006: Within 60 months after the
effective date of this AD, seal the ends of the fasteners on the
brackets that hold the vortex generators, and seal the ends of the
fasteners on certain stiffeners on the rear spar, as applicable. Do
the actions in accordance with the Accomplishment Instructions of
the service bulletin.
Wire Bundle Sleeve and Clamp Installation and Fastener Sealant
Application
(g) For airplanes identified in Boeing Alert Service Bulletin
767-57A0102, dated October 25, 2006: Within 60 months after the
effective date of this AD, change the wire bundle clamp
configurations at specified locations on the fuel tank walls, and
seal the fasteners and certain stiffeners at specified locations on
the fuel tank. Do the actions in accordance with the Accomplishment
Instructions of the service bulletin.
Alternative Methods of Compliance (AMOCs)
(h)(1) The Manager, Seattle Aircraft Certification Office (ACO),
FAA, has the authority to approve AMOCs for this AD, if requested in
accordance with the procedures found in 14 CFR 39.19.
[[Page 21169]]
(2) Before using any AMOC approved in accordance with Sec.
39.19 on any airplane to which the AMOC applies, notify the
appropriate principal inspector in the FAA Flight Standards
Certificate Holding District Office.
Issued in Renton, Washington, on April 17, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-8175 Filed 4-27-07; 8:45 am]
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