[Federal Register: August 9, 2004 (Volume 69, Number 152)]
[Rules and Regulations]
[Page 48133-48135]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr09au04-3]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2003-NM-107-AD; Amendment 39-13765; AD 2004-16-09]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to all Model 747 series airplanes, that 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
[[Page 48134]]
forward side. This action is necessary 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
and overpressurization of the tail section, and consequent loss of
control of the airplane. This action is intended to address the
identified unsafe condition.
DATES: Effective September 13, 2004.
The incorporation by reference of a certain publication listed in
the regulations is approved by the Director of the Federal Register as
of September 13, 2004.
ADDRESSES: The service information referenced in this AD may be
obtained from Boeing Commercial Airplanes, P.O. Box 3707, Seattle,
Washington 98124-2207. This information may be examined at the Federal
Aviation Administration (FAA), Transport Airplane Directorate, Rules
Docket, 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
.
FOR FURTHER INFORMATION CONTACT: Nicholas Kusz, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)
917-6432; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to all Model 747 series airplanes was
published in the Federal Register on February 6, 2004 (69 FR 5765).
That action proposed to require a repetitive detailed inspection 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.
Comments
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Agreement With Proposed Rule
Two commenters agree with the proposed rule.
Request To Change Inspection Intervals
One commenter requests that the repetitive inspection intervals be
changed. The commenter notes that the initial compliance time of 30,000
total flight cycles specified in paragraph (b) of the proposed rule
would impact its fleet within six to seven years. The commenter
suggests that the repetitive inspection interval for webs with
allowable oil can damage, specified in paragraph (e)(1) of the proposed
rule, be changed from 1,000 flight cycles to 1,200 flight cycles. The
commenter also suggests that the repetitive inspection interval for
webs with no oil can damage, specified in paragraph (c) of the proposed
rule, be changed from 2,000 flight cycles to 2,400 flight cycles. The
commenter contends that these changes would allow the repetitive
inspections to occur during scheduled heavy maintenance C-check level
visits.
The FAA does not agree with changing the repetitive inspection
intervals. In developing appropriate compliance times for this action,
we considered the safety implications, the manufacturer's
recommendations, and the practical aspect of accomplishing the
inspections within an interval of time that corresponds to the normal
maintenance schedules of most affected operators. The manufacturer
determined through tests and analysis that existing inspection programs
would not have found a crack in the web of the aft pressure bulkhead
prior to the crack reaching critical length. The repetitive inspection
intervals are based on the manufacturer's analysis of crack growth in
the web of the aft pressure bulkhead.
In light of all these factors, we consider the repetitive
inspection intervals required by paragraphs (c) and (e)(1) of the final
rule to be appropriate. Therefore, no change to the final rule is
necessary in this regard. However, according to the provisions of
paragraph (h) of the final rule, we may approve a request to adjust the
inspection intervals if the request includes data that prove that the
new inspection intervals would provide an acceptable level of safety.
Editorial Changes
We have reformatted paragraphs (f)(2) and (f)(3) of the proposed AD
by combining the paragraphs. Paragraph (f)(2) of the final rule
contains the actions that were specified in paragraphs (f)(2) and
(f)(3) of the proposed AD. We have also removed the reference to
paragraph (f)(2) from paragraph (e) of the final rule.
Conclusion
After careful review of the available data, including the comments
noted above, we have determined that air safety and the public interest
require the adoption of the rule with the changes previously described.
We have determined that these changes will neither increase the
economic burden on any operator nor increase the scope of the AD.
Cost Impact
There are approximately 1,140 airplanes of the affected design in
the worldwide fleet. The FAA estimates that 254 airplanes of U.S.
registry will be affected by this AD, that it will take approximately 6
work hours per airplane to accomplish the required actions, and that
the average labor rate is $65 per work hour. Based on these figures,
the cost impact of the AD on U.S. operators is estimated to be $99,060,
or $390 per airplane, per inspection cycle.
The cost impact figure discussed above is based on assumptions that
no operator has yet accomplished any of the requirements of this AD
action, and that no operator would accomplish those actions in the
future if this AD were not adopted. The cost impact figures discussed
in AD rulemaking actions represent only the time necessary to perform
the specific actions actually required by the AD. These figures
typically do not include incidental costs, such as the time required to
gain access and close up, planning time, or time necessitated by other
administrative actions.
Regulatory Impact
The regulations adopted herein 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. Therefore, it
is determined that this final rule does not have federalism
implications under Executive Order 13132.
For the reasons discussed above, I certify that this action (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. A final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it may be obtained
from the Rules Docket at the location provided under the caption
ADDRESSES.
[[Page 48135]]
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
0
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends part 39 of
the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness
directive:
2004-16-09 Boeing: Amendment 39-13765. Docket 2003-NM-107-AD.
Applicability: All Model 747 series airplanes; certificated in
any category.
Compliance: Required as indicated, unless accomplished
previously.
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.
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 and overpressurization of
the tail section, and consequent loss of control of the airplane,
accomplish the following:
Service Bulletin References
(a) The term ``service bulletin,'' as used in this AD, means the
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2482, dated October 3, 2002.
Initial and Repetitive Inspections
(b) Prior to the accumulation of 30,000 total flight cycles, or
within 1,000 flight cycles after the effective date of this AD,
whichever is later, 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.
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.''
(c) 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 (b) of this AD, repeat the detailed inspection
thereafter at intervals not to exceed 2,000 flight cycles.
Indication of Oil Can
(d) If any indication of an oil can is found during the detailed
inspection required by paragraph (b) or (c) 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.
(e) If no crack is found during the eddy current inspection
required by paragraph (d) of this AD, do the actions specified in
paragraph (e)(1) or (e)(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 (d) of this AD thereafter at intervals not to exceed
1,000 flight cycles. As an option, repair the oil can in accordance
with paragraph (e)(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 (e)(1) of this AD for that location only.
However, the repetitive detailed inspection required by paragraph
(c) of this AD is still required. If any oil can remains after the
repair, repeat the eddy current inspection specified in paragraph
(d) of this AD thereafter at intervals not to exceed 1,000 flight
cycles.
Indication of Previous Oil Can Repairs
(f) If any previous oil can repair is found during the detailed
inspection required by paragraph (b) or (c) 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 (c) 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
(e)(1) or (e)(2) of this AD, as applicable, at the time specified in
the applicable paragraph.
Repair of Cracks
(g) 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. For a repair method to be approved, the
approval must specifically reference this AD.
Alternative Methods of Compliance
(h) In accordance with 14 CFR 39.19, the Manager, Seattle ACO,
FAA, is authorized to approve alternative methods of compliance for
this AD.
Incorporation by Reference
(i) Unless otherwise specified in this AD, the actions shall be
done in accordance with Boeing Alert Service Bulletin 747-53A2482,
dated October 3, 2002. This incorporation by reference was approved
by the Director of the Federal Register in accordance with 5 U.S.C.
552(a) and 1 CFR part 51. Copies may be obtained from Boeing
Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.
Copies may be inspected at the 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
.
Effective Date
(j) This amendment becomes effective on September 13, 2004.
Issued in Renton, Washington, on July 30, 2004.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 04-17979 Filed 8-6-04; 8:45 am]
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