[Federal Register Volume 73, Number 128 (Wednesday, July 2, 2008)]
[Proposed Rules]
[Pages 37900-37903]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-14974]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2008-0731; Directorate Identifier 2008-NM-058-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D,
747-400F, 747SR, and 747SP 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 supersede an existing airworthiness
directive (AD) that applies to all Boeing Model 747 series airplanes.
The existing AD currently requires repetitive detailed inspections of
the aft pressure bulkhead for indications of ``oil cans'' and previous
oil can repairs, and corrective actions, if necessary. An oil can is an
area on a pressure dome web that moves when pushed from the forward
side. This proposed AD would reduce the compliance time for the initial
detailed inspection and clarify the applicability. This proposed AD
results from a report that cracks in oil-canned areas were found during
an inspection of the aft pressure bulkhead. We are proposing this AD to
detect and correct the propagation of fatigue cracks in the vicinity of
oil cans on the web of the aft pressure bulkhead, which could result in
rapid decompression of the airplane and overpressurization of the tail
section, and consequent loss of control of the airplane.
DATES: We must receive comments on this proposed AD by August 18, 2008.
[[Page 37901]]
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: Ivan Li, Aerospace Engineer, Airframe
Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind
Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6437;
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-2008-0731;
Directorate Identifier 2008-NM-058-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
On July 30, 2004, we issued AD 2004-16-09, amendment 39-13765 (69
FR 48133, August 9, 2004), for all Boeing Model 747 series airplanes.
That AD requires repetitive detailed inspections of the aft pressure
bulkhead for indications of ``oil cans'' and previous oil can repairs,
and corrective actions, if necessary. An oil can is an area on a
pressure dome web that moves when pushed from the forward side. That AD
resulted from a report indicating that a 2.1-inch long crack in the web
of the aft pressure bulkhead at the perimeter of an ``oil can'' was
found on a Model 747SR series airplane. We issued that AD to detect and
correct the propagation of fatigue cracks in the vicinity of oil cans
on the web of the aft pressure bulkhead, which could result in rapid
decompression of the airplane and overpressurization of the tail
section, and consequent loss of control of the airplane.
Actions Since Existing AD Was Issued
Since we issued AD 2004-16-09, we received a report that 9 cracks
(up to 0.4-inch long in 2 oil-canned areas) were found during an
inspection on the aft pressure bulkhead of a Model 747-200F series
airplane with about 21,000 total flight cycles. Boeing recommends
reducing the initial inspection threshold (required in paragraph (b) of
AD 2004-16-09) from 30,000 total flight cycles to 20,000 total flight
cycles.
Relevant Service Information
We have reviewed Boeing Alert Service Bulletin 747-53A2482,
Revision 1, dated February 21, 2008. The service bulletin describes
procedures that are the same as in Boeing Alert Service Bulletin 747-
53A2482, dated October 3, 2002, except for a reduction in a compliance
time and some editorial changes. Revision 1 of the service bulletin
also specifies contacting Boeing for repair data if any crack is found
during a detailed inspection of any previous ``oil can'' repair.
FAA's Determination and Requirements of the Proposed AD
We have evaluated all pertinent information and identified an
unsafe condition that is likely to develop on other airplanes of the
same type design. For this reason, we are proposing this AD, which
would supersede AD 2004-16-09 and would retain the requirements of the
existing AD. This proposed AD would also require accomplishing the
actions specified in the service bulletin described previously at a
reduced threshold, except as discussed under ``Differences Between the
Proposed AD and Revision 1 of the Service Bulletin.''
Differences Between the Proposed AD and Revision 1 of the Service
Bulletin
The service bulletin specifies to contact the manufacturer for
instructions on how to repair certain conditions, but this proposed AD
would require repairing those conditions in one of the following ways:
Using a method that we approve; or
Using data that meet the certification basis of the
airplane, and that have been approved by an Authorized Representative
for the Boeing Commercial Airplanes Delegation Option Authorization
Organization whom we have authorized to make those findings.
We have revised paragraph (g) of AD 2004-16-09 to allow repairs in
accordance with data that conforms to an airplane's type certificate
and that are approved by an Authorized Representative for the Boeing
Commercial Airplanes Delegation Option Authorization Organization whom
we have authorized to make such findings.
Change to Existing AD
This proposed AD would retain all requirements of AD 2004-16-09.
Since AD 2004-16-09 was issued, the AD format has been revised, and
certain paragraphs have been rearranged. As a result, the corresponding
paragraph identifiers have changed in this proposed AD, as listed in
the following table:
Revised Paragraph Identifiers
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Corresponding requirement in
Requirement in AD 2004-16-09 this proposed AD
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paragraph (a)............................. paragraph (f).
paragraph (b)............................. paragraph (g).
paragraph (c)............................. paragraph (h).
paragraph (d)............................. paragraph (i).
paragraph (e)............................. paragraph (j).
paragraph (f)............................. paragraph (k).
paragraph (g)............................. paragraph (l).
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The cost information specified in AD 2004-16-09 inadvertently
contained information on on-condition inspections. The cost
information, below, has been revised to state only the work hours
necessary for the initial and repetitive inspections specified in
paragraph (g) of this proposed AD.
Costs of Compliance
There are about 917 airplanes of the affected design in the
worldwide fleet.
[[Page 37902]]
This proposed AD would affect about 165 airplanes of U.S. registry.
The actions that are required by AD 2004-16-09 and retained in this
proposed AD 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 currently required actions to the U.S. operators is $26,400, 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.
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
removing amendment 39-13765 (69 FR 48133, August 9, 2004) and adding
the following new airworthiness directive (AD):
Boeing: Docket No. FAA-2008-0731; Directorate Identifier 2008-NM-
058-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by August
18, 2008.
Affected ADs
(b) This AD supersedes AD 2004-16-09.
Applicability
(c) This AD applies to all Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D,
747-400F, 747SR, and 747SP series airplanes, certificated in any
category.
Unsafe Condition
(d) This AD results from a report that cracks in oil-canned
areas were found during an inspection of the aft pressure bulkhead.
We are issuing this AD to detect and correct the propagation of
fatigue cracks in the vicinity of oil cans on the web of the aft
pressure bulkhead, which could result in rapid decompression of the
airplane and overpressurization of the tail section, and consequent
loss of control 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.
Note 1: This AD refers to certain portions of a Boeing service
bulletin for inspections and repair information. In addition, this
AD specifies requirements beyond those included in the service
bulletin. Where the AD and the service bulletin differ, the AD
prevails.
Service Bulletin References
(f) The term ``service bulletin,'' as used in this AD, means the
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2482, dated October 3, 2002; or Boeing Alert Service Bulletin
747-53A2482, Revision 1, dated February 21, 2008. After the
effective date of this AD, Revision 1 must be used.
Requirements of AD 2004-16-09, With Reduced Threshold
Initial and Repetitive Inspections
(g) At the earlier of the times specified in paragraphs (g)(1)
and (g)(2) of this AD, perform a detailed inspection of the aft
pressure bulkhead for indications of oil cans and previous oil can
repairs, in accordance with the service bulletin.
(1) Prior to the accumulation of 30,000 total flight cycles, or
within 1,000 flight cycles after September 13, 2004 (the effective
date of AD 2004-16-09), whichever is later.
(2) Prior to the accumulation of 20,000 total flight cycles, or
within 1,000 flight cycles after the effective date of this AD,
whichever occurs later.
Note 2: For the purposes of this AD, a detailed inspection is
``an intensive examination of a specific item, installation, or
assembly to detect damage, failure, or irregularity. Available
lighting is normally supplemented with a direct source of good
lighting at an intensity deemed appropriate. Inspection aids such as
mirrors, magnifying lenses, etc. may be necessary. Surface cleaning
and elaborate procedures may be required.''
(h) If no indication of an oil can is found and no indication of
a previous oil can repair is found during the detailed inspection
required by paragraph (g) of this AD, repeat the detailed inspection
thereafter at intervals not to exceed 2,000 flight cycles.
Indication of Oil Can
(i) If any indication of an oil can is found during the detailed
inspection required by paragraph (g) or (h) of this AD, before
further flight, perform an eddy current inspection of the web around
the periphery of the oil can indication for cracks, as shown in
Figure 3 of the service bulletin.
(j) If no crack is found during the eddy current inspection
required by paragraph (i) of this AD, do the actions specified in
paragraph (j)(1) or (j)(2) of this AD, as applicable.
(1) For the oil can that meets the allowable limits specified in
the service bulletin: Repeat the eddy current inspection specified
in paragraph (i) of this AD thereafter at intervals not to exceed
1,000 flight cycles. As an option, repair the oil can in accordance
with paragraph (j)(2) of this AD.
(2) For the oil can that does not meet the allowable limits
specified in the service bulletin: Before further flight, repair the
oil can in accordance with the service bulletin. If the repair
eliminates the oil can, accomplishment of this repair constitutes
terminating action for the repetitive eddy current inspection
requirements of paragraph (j)(1) of this AD for that location only.
However, the repetitive detailed inspection required by paragraph
(h) of this AD is still required. If any oil can remains after the
repair, repeat the eddy current inspection specified in paragraph
(i) of this AD thereafter at intervals not to exceed 1,000 flight
cycles.
[[Page 37903]]
Indication of Previous Oil Can Repairs
(k) If any previous oil can repair is found during the detailed
inspection required by paragraph (g) or (h) of this AD, before
further flight, do a detailed inspection of the web for cracks and
oil cans, as shown in Figure 4 or Figure 5 of the service bulletin,
as applicable.
(1) If no crack and no oil can are found, repeat the detailed
inspection in accordance with paragraph (h) of this AD.
(2) If any oil can is found, before further flight, do the eddy
current inspection for cracks, as shown in Figure 3 of the service
bulletin. If no crack is found during the eddy current inspection
required by this paragraph, do the actions specified in paragraph
(j)(1) or (j)(2) of this AD, as applicable, at the time specified in
the applicable paragraph.
Repair of Cracks
(l) If any crack is found during any inspection required by this
AD, before further flight, repair in accordance with the service
bulletin. If any crack or damage exceeds limits specified in the
service bulletin and the service bulletin specifies to contact
Boeing for appropriate action: Before further flight, repair per a
method approved by the Manager, Seattle Aircraft Certification
Office (ACO), FAA; or per data meeting the type certification basis
of the airplane approved by a Boeing Company Designated Engineering
Representative who has been authorized by the Manager, Seattle ACO,
to make such findings; or using a method approved in accordance with
the procedures specified in paragraph (n) of this AD. For a repair
method to be approved, the approval must specifically reference this
AD.
New Requirements of This AD
(m) As of the effective date of this AD, if any crack or damage
is found during any inspection required by this AD, and Boeing Alert
Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008,
specifies to contact Boeing for appropriate action (repair data):
Before further flight, repair the crack or damage using a method
approved in accordance with the procedures specified in paragraph
(n) of this AD.
Alternative Methods of Compliance (AMOCs)
(n)(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.
(3) An AMOC that provides an acceptable level of safety may be
used for any repair required by this AD, if it is approved by an
Authorized Representative for the Boeing Commercial Airplanes
Delegation Option Authorization Organization who has been authorized
by the Manager, Seattle ACO, to make those findings. For a repair
method to be approved, the repair must meet the certification basis
of the airplane.
(4) AMOCs approved previously in accordance with AD 2004-16-09
are not approved as AMOCs for the corresponding provisions of
paragraph (g) of this AD. They are approved as AMOCs for the
corresponding provisions of paragraphs (h), (i), (j), (k), (l), and
(m) of this AD.
Issued in Renton, Washington, on June 24, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E8-14974 Filed 7-1-08; 8:45 am]
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