[Federal Register: December 17, 2007 (Volume 72, Number 241)]
[Proposed Rules]
[Page 71275-71277]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr17de07-18]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-0339; Directorate Identifier 2007-NM-182-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 757 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 all Boeing Model 757 airplanes. This proposed AD would require
repetitive inspections of the anchor tab of the bulkhead seal
assemblies of the wing thermal anti-ice (TAI) system for cracks
[[Page 71276]]
at certain outboard stations of the left and right wings, and
corrective action if necessary. This proposed AD also provides optional
terminating action for the repetitive inspections. This proposed AD
results from reports of cracks found at the anchor tab of the bulkhead
seal assemblies of the wing TAI system. In one incident the anchor tab
and bulkhead seal assembly had separated because of the cracks. We are
proposing this AD to prevent failure of the anchor tab of the bulkhead
seal assembly, which in icing conditions could result in insufficient
airflow to the wing TAI system, subsequent ice on the wings, and
consequent reduced controllability of the airplane.
DATES: We must receive comments on this proposed AD by January 31,
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: Barbara Mudrovich, Aerospace Engineer,
Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98057-3356; telephone (425) 917-6477; 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-2007-0339;
Directorate Identifier 2007-NM-182-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
We have received reports of cracks found at the anchor tab of the
bulkhead seal assemblies of the wing thermal anti-ice (TAI) system on
Boeing Model 757 airplanes. In one incident the anchor tab and bulkhead
seal assembly had separated because of the cracks. The anchor tab of
the bulkhead seal assembly was held in position with a bolt. If the
anchor tab fails, the TAI spray tube disconnects from the TAI duct, and
it could not supply sufficient airflow for the wing TAI system. If the
flight is in icing conditions and there is insufficient airflow, it
could cause ice to form on the wings. These conditions, if not
corrected, could result in reduced controllability of the airplane.
Relevant Service Information
We have reviewed Boeing Special Attention Service Bulletins 757-30-
0021 and 757-30-0022, both Revision 1, both dated June 13, 2007. The
service bulletins describe procedures for repetitive detailed
inspections for cracks of the anchor tab of the bulkhead seal
assemblies of the wing TAI system at certain outboard stations of the
left and right wings, and corrective action before further flight if
necessary. The compliance time specified in the service bulletin for
the initial inspection is before the accumulation of 20,000 total
flight hours or within 36 months from the effective date on the service
bulletin, whichever occurs later.
The corrective action includes replacing the bulkhead seal assembly
or installing new duct anchor support brackets if cracks are found. If
the bulkhead seal assembly is replaced, but new support brackets are
not installed, the inspections must be repeated until the existing
brackets are replaced. Replacing the support brackets eliminates the
need for the repetitive inspections. The compliance time for the
repetitive inspections is at intervals not to exceed 6,000 flight
hours; for airplanes on which the bulkhead seal assemblies are
replaced, the inspection is repeated within 20,000 flight hours after
the replacement, and thereafter at intervals not to exceed 6,000 flight
hours.
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.
Costs of Compliance
There are about 929 airplanes of the affected design in the
worldwide fleet. This proposed AD would affect about 530 airplanes of
U.S. registry. The proposed inspection would take about 2 work hours
per airplane, at an average labor rate of $80 per work hour. Based on
these figures, the estimated cost of the proposed AD for U.S. operators
is $84,800, or $160 per airplane, per inspection cycle.
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.
[[Page 71277]]
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-2007-0339; Directorate Identifier 2007-NM-
182-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by January
31, 2008.
Affected ADs
(b) None.
Applicability
(c) This AD applies to all Boeing Model 757-200, -200PF, -200CB,
and -300 series airplanes, certificated in any category.
Unsafe Condition
(d) This AD results from reports of cracks found at the anchor
tab of the bulkhead seal assemblies of the wing thermal anti-ice
(TAI) system. In one incident the anchor tab and bulkhead seal
assembly had separated because of the cracks. We are issuing this AD
to prevent failure of the anchor tab of the bulkhead seal assembly,
which in icing conditions could result in insufficient airflow to
the wing TAI system, subsequent ice on the wings, and consequent
reduced controllability 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.
Repetitive Inspections/Corrective Action
(f) At the applicable times specified in paragraph 1.E.,
``Compliance,'' of Boeing Special Attention Service Bulletin 757-30-
0021 or 757-30-0022, both Revision 1, both dated June 13, 2007, as
applicable; except where the service bulletins specify starting the
compliance time ``* * * from the date on this service bulletin,''
this AD requires starting the compliance time from the effective
date of this AD: Perform detailed inspections for cracks of the
anchor tab of the bulkhead seal assemblies of the wing TAI system at
certain outboard stations of the left and right wings by doing all
the actions, including all applicable corrective actions, in
accordance with the Accomplishment Instructions of the applicable
service bulletin. Do all applicable corrective actions before
further flight.
Optional Terminating Action
(g) Installing a new duct anchor support bracket adjacent to the
bulkhead seal assemblies in accordance with Part 2 of the
Accomplishment Instructions of Boeing Special Attention Service
Bulletin 757-30-0021 or 757-30-0022, both Revision 1, both dated
June 13, 2007, as applicable, ends the repetitive inspections
required by paragraph (f) of this AD.
Credit for Actions Done According to Previous Issues of Service
Information
(h) Actions accomplished before the effective date of this AD in
accordance with Boeing Special Attention Service Bulletins 757-30-
0021 and 757-30-0022, both dated August 15, 2006, are considered
acceptable for compliance with the corresponding actions specified
in this AD.
Alternative Methods of Compliance (AMOCs)
(i)(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.
(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 December 10, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-24329 Filed 12-14-07; 8:45 am]
BILLING CODE 4910-13-P