[Federal Register: September 27, 2004 (Volume 69, Number 186)]
[Rules and Regulations]
[Page 57636-57638]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr27se04-4]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2002-NM-263-AD; Amendment 39-13800; AD 2004-19-06]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 767-200, -300, and -300F
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 Boeing Model 767-200, -300, and -300F series
airplanes, that requires inspections to detect cracking or corrosion of
the fail-safe straps between the side fitting of the rear spar bulkhead
at body station 955 and the skin; and follow-on/corrective actions.
This action is necessary to detect and correct fatigue cracking or
corrosion of the fail-safe straps, which could result in cracking of
adjacent structure and consequent reduced structural integrity of the
fuselage. This action is intended to address the identified unsafe
condition.
DATES: Effective November 1, 2004.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of November 1, 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: Suzanne Masterson, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)
917-6441; 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 Boeing Model 767-200, -300,
and -300F series airplanes was published in the Federal Register on
March 5, 2004 (69 FR 10364). That action proposed to require
inspections to detect cracking or corrosion of the fail-safe straps
between the side fitting of the rear spar bulkhead at body station 955
and the skin; and follow-on/corrective actions.
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.
Request To Withdraw Notice of Proposed Rulemaking (NPRM)
One commenter requests that the NPRM be withdrawn. The commenter
states that none of the reported incidents described in the Discussion
section of the NPRM can be attributed completely to fatigue. The
commenter also states that all data to date that suggest this is a
fatigue issue are flawed by the fact that there have been three
separate contributing factors--corrosion, surface damage, and fretting/
small gouging.
The commenter has inspected 43 airplanes and found only one case of
cracking, which was the result of surface damage during installation of
the fail-safe strap in the factory. The commenter discovered the damage
during normal routine maintenance, using an item currently in the
maintenance program, and believes that these standard inspections are
sufficient to maintain the continued safety of the airplanes. The
commenter also points out that this airplane and the second airplane
referred to in the Background section of Boeing Alert Service Bulletin
767-53A0100, dated September 26, 2002 (referenced in the AD as the
appropriate source of service bulletin for the required actions), have
early line numbers and ``were [essentially] hand built.'' The commenter
contends that if this is truly a fatigue issue, there would have been
at least one other occurrence
[[Page 57637]]
of fatigue cracking in the 20-plus years that the fleet has been
operating. The commenter also notes that Boeing has acknowledged that
no cracking was found on its fatigue test article that was tested for
100,000 flight cycles.
We do not agree that the NPRM should be withdrawn. It was not our
intention in the Discussion section of the NPRM to imply that the crack
findings were attributed completely to fatigue. Because of the critical
function of the fail-safe strap, we find that inspections are necessary
to detect cracking or corrosion, regardless of the mode by which the
crack initiates. Since the issuance of the NPRM, we have received two
additional reports of cracks in the fail-safe strap: one report for an
airplane that had accumulated 31,809 total flight cycles, and one
report from full-scale fatigue testing on a 767 test article. The
cracks on the fatigue test article were hidden and were not detected
until the joint was disassembled. We have determined that the existing
routine maintenance inspections are not sufficient to detect cracked
fail-safe straps in a timely, reliable manner. Therefore, this AD is
appropriate and warranted.
Request To Delay Issuance of AD
One commenter requests the final rule not be issued until the lack
of available replacement straps is resolved. The commenter states that
the strap is not repairable at this time. The commenter also states
that the airplane manufacturer is working on potential repairs and an
analysis to determine if the replacement strap should be strengthened
from the original design. The study should be completed by April 15,
2004.
We do not agree that the strap is not repairable. All airplanes on
which cracked or corroded straps were found have been successfully
repaired with new fail-safe straps, which indicates to us that future
crack findings can be successfully repaired. The airplane manufacturer
has informed us that the commenter received preliminary information
about the study, and that the study is not completed yet. In light of
the critical nature of the identified unsafe condition, we do not
consider that delaying this action until after the airplane
manufacturer develops either an easier repair or an improved strap
design is warranted. However, under the provisions of paragraph (c) of
the final rule, we may consider requests for approval of an alternative
method of compliance if sufficient data are submitted to substantiate
that such a design change would provide an acceptable level of safety.
Request To Correct Information in the Service Bulletin
One commenter requests the following changes to Boeing Alert
Service Bulletin 767-53A0100:
1. Mark the area of interest (5-inch radius) on figure 2 of the
service bulletin, or add a new photo to the photos already posted on
Boeing's Web site under 767-FTD-53-02004 article and refer to the new
photo or article in the NPRM. The commenter believes that the
instructions in step 1 of figure 2 are too general for the complexity
of the structure.
We partially agree with the commenter. We agree that the structure
is complex; however, the intent of the service bulletin is to determine
whether cracks have begun to propagate in adjacent structure due to the
existence of a crack in the fail-safe straps. The service bulletin
defines the extent of the adjacent structure to be inspected as
``within 5 inches of the area of the typical crack area,'' as shown in
Detail A of figure 2. This definition applies to the structure that is
visible after doing the access procedures in the Work Instructions of
the service bulletin. We have determined that the inspection is
possible without further clarification. No change to the final rule is
necessary in this regard.
2. Revise step 2 of the Work Instructions of the service bulletin
to read, ``Open the Main Landing Gear (MLG) doors * * *'' instead of
``Open the Main Landing Green (MGL) door. * * *'' Revise steps 2 and 8
to refer to 767 Airplane Maintenance Manual (AMM) 32-12-00, not 32-00-
20.
We partially agree. We agree with the commenter that the word
``green'' in the service bulletin is incorrect. We also agree that the
767 AMM 32-00-20 does not include instructions for opening the MLG
doors. However, the correct reference is 767 AMM 32-00-15, not 767 AMM
32-12-00 as suggested by the commenter. 767 AMM 32-00-15, which is
referred to in steps 3 and 7 of the Work Instructions, describes
procedures for opening and closing the MLG doors using the ground
release lever before installing the MLG door locks and after removing
them. Boeing has no plans at this time to revise the service bulletin
to fix these errors. Therefore, we have added a note in the final rule
to point out the errors in the service bulletin.
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 as proposed.
Interim Action
This is considered to be interim action until final action is
identified, at which time we may consider further rulemaking.
Cost Impact
There are approximately 833 airplanes of the affected design in the
worldwide fleet. We estimate that 354 airplanes of U.S. registry will
be affected by this AD, that it will take approximately 2 work hours
per airplane to accomplish the required inspections, 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 $46,020, or
$130 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 57638]]
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:
2004-19-06 Boeing: Amendment 39-13800. Docket 2002-NM-263-AD.
Applicability: All Model 767-200, -300, and -300F series
airplanes, certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To detect and correct fatigue cracking or corrosion of the fail-
safe straps, which could result in cracking of adjacent structure
and consequent reduced structural integrity of the fuselage,
accomplish the following:
Inspections and Follow-On/Corrective Actions
(a) Except as provided by paragraph (b) of this AD, prior to the
accumulation of 15,000 total flight cycles, or within 3,000 flight
cycles after the effective date of this AD, whichever occurs later,
perform a detailed inspection and eddy current inspection to detect
cracking or corrosion of the fail-safe straps between the side
fitting of the rear spar bulkhead at BS 955 and the skin, per Figure
2 of the Accomplishment Instructions of Boeing Alert Service
Bulletin 767-53A0100, dated September 26, 2002.
Note 1: For the purposes of this AD, a detailed inspection is
defined as: ``An intensive visual examination of a specific
structural area, system, installation, or assembly to detect damage,
failure, or irregularity. Available lighting is normally
supplemented with a direct source of good lighting at intensity
deemed appropriate by the inspector. Inspection aids such as mirror,
magnifying lenses, etc., may be used. Surface cleaning and elaborate
access procedures may be required.''
(1) If no crack or corrosion is found, repeat the inspections
thereafter at intervals not to exceed 6,000 flight cycles or 36
months, whichever occurs first.
(2) If any crack or corrosion is found, before further flight,
repair per a method approved by the Manager, Seattle Aircraft
Certification Office (ACO), FAA; or 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.
(b) For airplanes on which the fail-safe strap has been replaced
before the effective date of this AD: Do the actions required by
paragraph (a) of this AD within 12,000 flight cycles after
accomplishing the replacement.
Note 2: Steps 2 and 8 of the Work Instructions of Boeing Alert
Service Bulletin 767-53A0100, dated September 26, 2002, refer
incorrectly to 767 Airplane Maintenance Manual (AMM) 32-00-20 for
opening the MLG doors; the correct reference is 767 AMM 32-00-15,
which is referred to in steps 3 and 7 of the Work Instructions. Step
2 also should state ``Open Main Landing Gear (MLG) doors'' instead
of ``Open Main Landing Green (MLG) doors.''
Alternative Methods of Compliance
(c)(1) In accordance with 14 CFR 39.19, the Manager, Seattle
ACO, FAA, is authorized to approve alternative methods of compliance
(AMOCs) for this AD.
(2) An AMOC that provides an acceptable level of safety may be
used for any repair required by this AD, if it is approved by a
Boeing Company Designated Engineering Representative who has been
authorized by the Manager, Seattle ACO, to make such findings.
Incorporation by Reference
(d) Unless otherwise specified in this AD, the actions shall be
done in accordance with Boeing Alert Service Bulletin 767-53A0100,
dated September 26, 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
(e) This amendment becomes effective on November 1, 2004.
Issued in Renton, Washington, on September 13, 2004.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 04-21272 Filed 9-24-04; 8:45 am]
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