[Federal Register: November 25, 2008 (Volume 73, Number 228)]
[Rules and Regulations]
[Page 71534-71537]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr25no08-7]
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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;
Amendment 39-15740; AD 2008-23-19]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 757 Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: We are adopting a new airworthiness directive (AD) for certain
Boeing Model 757 airplanes. This AD requires sealing the fasteners on
the front and rear spars inside the left and right main fuel tanks and
on the rear spar and lower panel of the center fuel tank. This AD also
requires 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 AD results from a fuel system
review conducted by the manufacturer. We are issuing this AD to detect
and correct improper wire bundle support installation and sleeving and
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: This AD is effective December 30, 2008.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of December 30,
2008.
ADDRESSES: 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 AD, the regulatory evaluation,
any comments received, and other information. The address for the
Docket Office (telephone 800-647-5527) is the Document Management
Facility, U.S. Department of Transportation, Docket Operations, M-30,
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE.,
Washington, DC 20590.
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:
Discussion
We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to include an airworthiness directive (AD) that would apply to
certain Boeing Model 757 series airplanes. That NPRM was published in
the Federal Register on December 6, 2007 (72 FR 68764). That NPRM
proposed to 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. That NPRM also proposed to 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.
Comments
We gave the public the opportunity to participate in developing
this AD. We considered the comments received from the four commenters.
Request for Justification of the NPRM
Northwest Airlines (NWA) has no objection to the intent of the
NPRM, but it states it is not clear that we have shown that the
probability of a fuel tank explosion due to unsealed fuel tank
fasteners reaches the threshold for justifying the proposed
modification. NWA requests that we provide more detail regarding the
risk and benefit of the NPRM.
We agree to provide clarification. The unsafe condition encompassed
the scenario of single failures (for example, a wire bundle clamp
failure that could result in wire bundle contact with the fuel tank
causing an ignition source internal to the tank) that place an airplane
at risk of a fuel tank explosion.
[[Page 71535]]
The in-tank sealant is designed to provide a second level of protection
against fuel tank ignition by encapsulating and containing the
potential source of ignition. Further, the risk level associated with
this single failure scenario was determined to warrant the actions
required by this AD. No change to the AD is necessary in this regard.
Request To Clarify the Unsafe Condition
Boeing requests that we revise paragraph (d) of the NPRM to cover
the requirement to do the general visual inspection for wire bundle
support installation and sleeving. Boeing states that failures of the
wire bundles and shorting to clamps are the prime candidates for the
fault current source, and that they should be identified as the unsafe
condition.
We agree because accomplishing the general visual inspections for
wire bundle supports and sleeving is one of the requirements of this
AD. We have revised the Summary and paragraph (d) of this AD
accordingly.
Request To Clarify Requirements
Boeing requests that we revise the Summary of the NPRM to include
the requirement to seal the fasteners on the rear spar of the center
fuel tank. Boeing states that this action is called out on page 149 in
view B of Figure 7 of Boeing Alert Service Bulletin 757-57A0064, dated
July 16, 2007.
We agree and have revised the Summary of this AD accordingly.
Although the specific location of the ``rear spar of the center tank''
was inadvertently omitted from the Summary of the NPRM, it was covered
by paragraph (f) of the NPRM, which specified accomplishing all of the
applicable actions specified in the Accomplishment Instructions of
Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007.
Request To Delay Issuance To Provide Instructions for Maintaining the
Design Change
Continental Airlines (CAL) is concerned that not enough attention
has been given to ensure that the changes detailed in Boeing Alert
Service Bulletin 757-57A0064, dated July 16, 2007, are preserved for
the long-term operation of its Model 757 fleet. CAL states that, other
than this service bulletin and some generic information found in the
Boeing 757 Maintenance Planning Data (MPD) document, there are no other
published ``maintenance'' documents currently available to show each
specific requirement as detailed in the service bulletin. CAL further
states that information detailed by the service bulletin must be
available in manuals that are routinely used by maintenance personnel.
CAL asserts that making this information available will prevent the
inadvertent reversal of the implemented changes, which could lead to
violation of the NPRM, in addition to compromising the higher level of
safety intended for the Model 757 fleet.
CAL believes the current program, as provided by the service
bulletin and proposed by the NPRM, is not ready to be implemented. CAL
states that, if the NPRM is mandated as proposed, CAL would not be able
to incorporate the modification on its Model 757-200 series airplanes,
and a high risk of future de-modification would exist for those
airplanes that could be modified. CAL recommends that we coordinate
with Boeing regarding its requested changes.
We infer that CAL requests that we delay issuance of the AD until
Boeing has revised the applicable maintenance documents to provide
detailed information for maintenance personnel to maintain the required
design change. We agree with CAL's concern about ensuring that the
requirements of this AD are maintained throughout the life of the
airplane. We are considering additional rulemaking in this regard.
However, we disagree with delaying issuance of the final rule until
Boeing has worked through its process to revise the applicable
maintenance documents. To delay this action would be inappropriate,
since we have determined that an unsafe condition exists and that the
actions required by this AD must be mandated to ensure continued
safety. However, as a result of this comment, we have initiated
discussions with Boeing about including more detail in the Instructions
for Continued Airworthiness (ICA) to ensure that the integrity of this
AD is maintained throughout the life of an airplane. Those discussions
are ongoing at this time. We have not changed the AD in this regard.
Request To Delay Issuance of the AD To Provide Instructions for
Modified Airplanes
CAL states that all of its 41 Model 757-200 series airplanes were
modified in the past with a Aviation Partners Boeing (APB) winglet
design that incorporated significant changes to the forward and rear
spars. CAL states that Boeing has acknowledged that Boeing Alert
Service Bulletin 757-57A0064, dated July 16, 2007, does not include
instructions for the configuration of CAL's modified airplanes. CAL
also states that Boeing is currently assessing the configuration of
CAL's airplanes and that Boeing will respond with an action plan.
We infer that CAL requests that we delay issuance of the AD until
Boeing has revised the service bulletin to provide instructions for
accomplishing the modification on airplanes equipped with APB winglets
installed in accordance with Supplemental Type Certificate (STC)
ST01518SE. We disagree with delaying issuance of the final rule because
we have determined that an unsafe condition exists and that the actions
required by this AD must be mandated to ensure continued safety.
Further, we have discussed CAL's concern about the service bulletin
instructions with both the airplane and winglet manufacturers. They
both indicated that the procedures in the service bulletin, as
published, can be accomplished on airplanes equipped with APB winglets
installed in accordance with STC ST01518SE. We have not changed the AD
in this regard.
Request To Extend Compliance Time
European Air Transport, on behalf of DHL Air, and NWA request that
we extend the compliance time from 60 months to 72 months. European Air
Transport states that, due to the high number of work hours needed to
accomplish the proposed actions, it plans to do the work during a 4C-
check (corresponding to 72 months, 24,000 flight hours, or 12,000
flight cycles, whichever occurs first). European Air Transport also
states that a 60-month compliance time would require it to do the
proposed actions on some of its airplanes outside the 4C-check, but
that a 72-month compliance time will allow it to do the proposed
actions on the entire fleet during base maintenance.
NWA states that, due to access requirements, it considers the
proposed modification to be consistent with a D-check level of work.
NWA also states that it does not understand the substantiation for the
60-month compliance time and believes that doing the work during
scheduled fuel tank access will ensure more consistent quality of the
modification, as well as reduced costs to industry. NWA also states
that it is unaware of any accident or incident that has been attributed
to unsealed fuel tank fasteners, or that the risk is such that
compliance should be required within 60 months instead of 72 months.
NWA believes that a 1-year extension of the compliance time would not
have an appreciable impact on safety. NWA further states its request is
consistent with the FAA harmonization policy of the aging airplane
programs in
[[Page 71536]]
accordance with ``Fuel Tank Safety Compliance Extension (Final Rule)
and Aging Airplane Program Update (Request for Comments)'' (69 FR
45936, July 30, 2004).
We do not agree with the request to extend the compliance time. In
developing an appropriate compliance time for this action, we
considered the urgency associated with the subject unsafe condition and
the practical aspect of accomplishing the required modification within
a period of time that corresponds to the normal scheduled maintenance
for most affected operators. We recognize that operators have different
maintenance schedules for accomplishing heavy maintenance on Model 757
airplanes, but at the same time we understand that a 60-month
compliance time will accommodate most operators' schedules for that
type of work. However, according to the provisions of paragraph (g) of
this AD, we may approve requests to adjust the compliance time if the
request includes data that prove that the new compliance time would
provide an acceptable level of safety. We have not changed the AD in
this regard.
Conclusion
We reviewed the relevant data, considered the comments received,
and determined that air safety and the public interest require adopting
the AD with the changes described previously. We also determined that
these changes will not increase the economic burden on any operator or
increase the scope of the AD.
Costs of Compliance
There are about 1,049 airplanes of the affected design in the
worldwide fleet. This AD affects about 539 airplanes of U.S. registry.
The required actions 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 cost about $325 per airplane. Based on these
figures, the estimated cost of the 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
This AD will not have federalism implications under Executive Order
13132. This AD will 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 this AD:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866,
(2) Is not a ``significant rule'' under 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.
Adoption of the Amendment
0
Accordingly, under the authority delegated to me by the Administrator,
the FAA amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
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]
0
2. The FAA amends Sec. 39.13 by adding the following new AD:
2008-23-19 Boeing: Amendment 39-15740. Docket No. FAA-2007-0289;
Directorate Identifier 2007-NM-208-AD.
Effective Date
(a) This airworthiness directive (AD) is effective December 30,
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 detect and correct improper
wire bundle support installation and sleeving and 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 (ACO),
FAA, ATTN: Judy Coyle, Aerospace Engineer, Propulsion Branch, ANM-
140S, FAA, Seattle ACO, 1601 Lind Avenue SW., Renton, Washington
98057-3356; telephone (425) 917-6497; fax (425) 917-6590; has the
authority to approve AMOCs for this AD, if requested, using 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.
Material Incorporated by Reference
(h) You must use Boeing Alert Service Bulletin 757-57A0064,
dated July 16, 2007, to do the actions required by this AD, unless
the AD specifies otherwise.
(1) The Director of the Federal Register approved the
incorporation by reference of this service information under 5
U.S.C. 552(a) and 1 CFR part 51.
(2) For service information identified in this AD, contact
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington
98124-2207; telephone 206-544-9990; fax 206-766-5682; e-mail
DDCS@boeing.com; Internet https://www.myboeingfleet.com.
(3) You may review copies of the service information
incorporated by reference at the
[[Page 71537]]
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington; or at the National Archives and Records Administration
(NARA). For information on the availability of this material at
NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_
register/code_of_federal_regulations/ibr_locations.html.
Issued in Renton, Washington, on October 24, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E8-27168 Filed 11-24-08; 8:45 am]
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