[Federal Register Volume 64, Number 90 (Tuesday, May 11, 1999)]
[Rules and Regulations]
[Pages 25194-25197]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-11618]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-100-AD; Amendment 39-11162; AD 99-10-09]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747-100, 747-200, and 747-
SP Series Airplanes and Military Type E-4B Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Boeing Model 747-100, -200, and 747-SP series
airplanes and military type E-4B airplanes, that requires repetitive
inspections to detect cracking of the wing front spar web, and repair
of cracked structure. This amendment also provides for optional
terminating action for the repetitive inspection requirements. This
amendment is prompted by reports indicating that fatigue cracks were
found on the aft surface of the wing front spar web. The actions
specified by this AD are intended to detect and correct such fatigue
cracking, which could result in a fuel leak, and consequent increased
risk of a fire.
DATES: Effective June 15, 1999.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of June 15, 1999.
ADDRESSES: The service information referenced in this AD may be
obtained from Boeing Commercial Airplane Group, 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 Office of
the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
FOR FURTHER INFORMATION CONTACT: Tamara L. Anderson, Aerospace
Engineer, Airframe Branch, ANM-120S, FAA, Transport Airplane
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue,
SW., Renton, Washington 98055-4056; telephone (425) 227-2771; fax (425)
227-1181.
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 certain Boeing
[[Page 25195]]
Model 747-100, -200, and 747-SP series airplanes and military type E-4B
airplanes was published in the Federal Register on May 28, 1998 (63 FR
29151). That action proposed to require repetitive inspections to
detect cracking of the wing front spar web, and repair of cracked
structure. That proposal also provided for optional terminating action
for the repetitive inspection requirements.
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.
One commenter supports the proposed rule, and one commenter has no
objection to the proposed rule.
Request to Allow Use of Additional Service Information
Two commenters request that the proposed rule be revised to allow
inspection and modification of the wing front spar web to be
accomplished in accordance with the original issue of Boeing Alert
Service Bulletin 747-57A2303, dated December 19, 1996. The notice of
proposed rulemaking (NPRM) proposed to require inspection and
modification of the wing front spar web in accordance with only Boeing
Service Bulletin 747-57A2303, Revision 1, dated September 25, 1997. The
commenters point out that Boeing Service Bulletin 747-57A2303, Revision
1, states that no more work is necessary for airplanes inspected or
modified in accordance with the original issue of the service bulletin.
One of the commenters states that revising the final rule to allow
inspection and modification of the wing front spar web in accordance
with the original issue of the service bulletin would preclude the need
for affected operators to obtain approval for an alternative method of
compliance.
The FAA concurs with the commenters' request to allow inspection
and modification of the wing front spar web in accordance with the
original issue of Boeing Alert Service Bulletin 747-57A2303. The FAA
has reviewed the original issue of the service bulletin and determined
that the procedures in the original issue are substantially similar to
those described in Revision 1. Therefore, ``NOTE 2'' has been added to
this final rule to specify that inspections and modifications
accomplished prior to the effective date of this AD in accordance with
the original issue of Boeing Alert Service Bulletin 747-57A2303 are
considered acceptable for compliance with this AD.
Request to Terminate Repetitive Inspections Required by AD 95-02-15
One commenter requests that the proposal (Docket number 97-NM-100-
AD) be revised to state that, if the terminating action proposed in the
NPRM (replacement of the wing front spar web with a new shot-peened
wing front spar web) is accomplished, certain inspections outboard of
front spar station inboard (FSSI) 669 that are currently required by AD
95-02-15, amendment 39-9134 (60 FR 9613, March 21, 1995), are no longer
necessary. The commenter points out that the subject area in the
proposal overlaps considerably with the subject area of AD 95-02-15.
The commenter also states that a similar revision should be made to the
NPRM for docket number 97-NM-82-AD, which proposed the supersedure of
AD 95-02-15, to state that certain inspections outboard of FSSI 669 are
no longer necessary if the replacement of the wing front spar web with
a new shot-peened wing front spar web is accomplished in accordance
with this AD. The commenter states that addressing the area of overlap
in the final rule would preclude the need for affected operators to
obtain FAA approval for an alternative method of compliance for the
inspections of the subject area of AD 95-02-15.
The FAA partially concurs with the commenter's request to revise
the NPRM's for docket numbers 97-NM-82-AD and 97-NM-100-AD. On July 15,
1998, the FAA issued AD 98-15-21, amendment 39-10672 (63 FR 39487,
dated July 23, 1998), which supersedes AD 95-02-15. Because that AD has
already been issued, no revision to that final rule will be made at
this time. However, the FAA concurs that accomplishment of the optional
terminating action specified in this final rule would eliminate the
need for inspections in accordance with AD 98-15-21 for the modified
area only (i.e., FSSI 669 to FSSI 697 inclusive). Therefore, paragraph
(c) of this final rule has been revised to state that replacement of
the affected wing front spar web with a new shot-peened wing front spar
web in accordance with Boeing Service Bulletin 747-57A2303, Revision 1,
constitutes terminating action for repetitive inspections in accordance
with AD 98-15-21 for the modified area only. In addition, ``NOTE 3''
has been added to this final rule to clarify that the area subject to
the optional terminating action specified in paragraph (c) of this
final rule overlaps with part of the wing front spar that is the
subject of AD 98-15-21.
Request to Approve Alternative Method of Compliance for Terminating
Action
One commenter requests that the proposed rule be revised to allow
modifications of the wing front spar web accomplished previously in
accordance with Boeing Service Letter 747-SL-57-084-C, dated October
12, 1996, and Boeing Repair Drawing 112U8040, to be considered
terminating action for the requirements of this AD. The commenter
states that such a modification was coordinated through the
manufacturer, and the commenter has accomplished the modification on
several of its airplanes.
The FAA does not concur with the commenter's request to approve an
alternative method of compliance for the terminating action. The
service letter and repair drawing referenced by the commenter are not
approved by the FAA. Therefore, the FAA finds that modifications
accomplished in accordance with these data may not be adequate to
ensure that the unsafe condition is adequately addressed. In addition,
the FAA finds that adding such an alternative method of compliance for
the terminating action to the final rule would unduly complicate this
AD action and may be confusing to some operators. However, the operator
may request approval of an alternative method of compliance in
accordance with paragraph (d) of the final rule. No change to the final
rule is necessary in this regard.
Explanation of Changes Made to the Proposal
The FAA has revised paragraph (b)(2) of the final rule to add a
provision that allows repair of any crack in the subject area to be
accomplished in accordance with data meeting the type certification
basis of the airplane approved by a Boeing Company Designated
Engineering Representative who has been authorized by the FAA to make
such findings.
Conclusion
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the changes described
previously. The FAA has 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 190 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 95 airplanes of U.S. registry
will be
[[Page 25196]]
affected by this AD, that it will take approximately 64 work hours per
airplane to accomplish the required inspection, at an average labor
rate of $60 per work hour. Based on these figures, the cost impact of
the inspection required by this AD on U.S. operators is estimated to be
$364,800, or $3,840 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.
Should an operator elect to accomplish the optional terminating
modification, it would take approximately 518 work hours per airplane
to accomplish the modification, at an average labor rate of $60 per
work hour. Required parts would cost approximately $17,000 per
airplane. Based on these figures, the cost impact of the optional
terminating modification is estimated to be $48,080 per airplane.
Regulatory Impact
The regulations adopted herein will not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
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
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. Section 39.13 is amended by adding the following new
airworthiness directive:
99-10-09 Boeing: Amendment 39-11162. Docket 97-NM-100-AD.
Applicability: Model 747-100, 747-200, and 747-SP series
airplanes and military type E-4B airplanes; as listed in Boeing
Service Bulletin 747-57A2303, Revision 1, dated September 25, 1997;
certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must request approval for an
alternative method of compliance in accordance with paragraph (d) of
this AD. The request should include an assessment of the effect of
the modification, alteration, or repair on the unsafe condition
addressed by this AD; and, if the unsafe condition has not been
eliminated, the request should include specific proposed actions to
address it.
Compliance: Required as indicated, unless accomplished
previously.
Note 2: Inspections and modifications accomplished prior to the
effective date of this AD in accordance with Boeing Alert Service
Bulletin 747-57A2303, dated December 19, 1996, are considered
acceptable for compliance with the applicable action specified in
this amendment.
To detect and correct fatigue cracking of the wing front spar
web, which could result in a fuel leak, and consequent increased
risk of a fire, accomplish the following:
Initial and Repetitive Inspections
(a) Perform an ultrasonic inspection to detect cracking of the
wing front spar web at the fastener rows behind and between the
upper link fittings for the number 2 and 3 engine struts, in
accordance with the Accomplishment Instructions of Boeing Service
Bulletin 747-57A2303, Revision 1, dated September 25, 1997, at the
time specified in paragraph (a)(1) or (a)(2) of this AD, as
applicable.
(1) For airplanes identified as Group 1, 2, 3, or 5 in the alert
service bulletin: Inspect prior to the accumulation of 12,500 total
flight cycles, or within 15 months after the effective date of this
AD, whichever occurs later. Repeat the inspection thereafter at
intervals not to exceed 2,200 flight cycles.
(2) For airplanes identified as Group 4, 6, 7, 8, 9, or 10 in
the alert service bulletin: Inspect prior to the accumulation of
18,000 total flight cycles, or within 15 months after the effective
date of this AD, whichever occurs later. Repeat the inspection
thereafter at intervals not to exceed 3,000 flight cycles.
Corrective Actions
(b) If any crack is found during any inspection required by
paragraph (a) of this AD, prior to further flight, accomplish either
paragraph (b)(1) or (b)(2) of this AD.
(1) Accomplish the terminating action in accordance with the
Accomplishment Instructions of Boeing Service Bulletin 747-57A2303,
Revision 1, dated September 25, 1997. Accomplishment of this action
constitutes terminating action for the repetitive inspection
requirements of this AD; or
(2) Repair in accordance with a method approved by the Manager,
Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane
Directorate; or in accordance with 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 by the Manager, Seattle, ACO, as required by this
paragraph, the Manager's approval letter must specifically reference
this AD.
Optional Terminating Action
(c) Replacement of the affected wing front spar web with a new
shot-peened wing front spar web in accordance with the
Accomplishment Instructions of Boeing Service Bulletin 747-57A2303,
Revision 1, dated September 25, 1997, constitutes terminating action
for the repetitive inspection requirements of this AD, and, for the
modified area only, for the repetitive inspection requirements of AD
98-15-21, amendment 39-10672.
Note 3: The area subject to the optional terminating action
specified in paragraph (c) of this AD overlaps with part of the wing
front spar that is the subject of AD 98-15-21.
Alternative Method of Compliance
(d) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, Seattle ACO. Operators shall submit
their requests through an appropriate FAA Principal Maintenance
Inspector, who may add comments and then send it to the Manager,
Seattle ACO.
Note 4: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
Special Flight Permits
(e) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where
the requirements of this AD can be accomplished.
Incorporation by Reference
(f) The inspections and replacement shall be done in accordance
with Boeing Service Bulletin 747-57A2303, Revision 1, dated
[[Page 25197]]
September 25, 1997. 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 Airplane Group, 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
Office of the Federal Register, 800 North Capitol Street, NW., suite
700, Washington, DC.
Effective Date
(g) This amendment becomes effective on June 15, 1999.
Issued in Renton, Washington, on May 3, 1999.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-11618 Filed 5-10-99; 8:45 am]
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