[Federal Register Volume 60, Number 126 (Friday, June 30, 1995)]
[Rules and Regulations]
[Pages 34107-34109]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-14631]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-120-AD; Amendment 39-9279; AD 95-12-26]
Airworthiness Directives; Boeing Model 747SP Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to certain Boeing Model 747SP series airplanes, that
currently requires repetitive inspections for cracks in the web of the
wing front spar over engine numbers 2 and 3, and repair, if necessary.
This amendment requires additional inspections in an area beyond that
specified in the existing AD. This action also would provide for a new,
optional modification, which, if accomplished, would constitute
terminating action for the repetitive inspections. This amendment is
prompted by a report of cracking in the web in an area outside the
inspection zone specified in the existing AD. A crack in the web that
is not detected before it extends outside the chord footprints can
allow fuel leakage. The actions specified by this AD are intended to
prevent fuel leakage onto an engine and a resultant fire due to
cracking in the web of the wing front spar.
DATES: Effective July 31, 1995.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of July 31, 1995.
ADDRESSES: The service information referenced in this AD may be
obtained from Boeing Commercial Airplane
[[Page 34108]]
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: Tim Backman, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle
Aircraft Certification Office, 1601 Lind Avenue SW., Renton, Washington
98055-4056; telephone (206) 227-2776; fax (206) 227-1181.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) by superseding AD 90-17-18,
amendment 39-6702 (55 FR 33279, August 15, 1990), which is applicable
to certain Boeing Model 747SP series airplanes, was published as a
supplemental notice of proposed rulemaking (NPRM) in the Federal
Register on February 21, 1995 (60 FR 9645). The action proposed to
require repetitive inspections to detect cracks in the web of the wing
front spar in an area beyond that specified in the existing AD, and
modification, if cracking is found. The action also proposed to provide
for a new, optional modification, which, if accomplished, would
constitute terminating action for the repetitive inspections.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the single comment received.
The commenter supports the proposed rule.
Since the issuance of the supplemental NPRM, the manufacturer
completed development of the modification program for the engine struts
on the affected airplanes; subsequently, the FAA approved that program.
On May 10, 1995, the FAA issued AD 95-10-16, amendment 39-9233 (60 FR
27008, May 22, 1995), which is applicable to Boeing Model 747 series
airplanes equipped with JT9D-3 and -7 series engines, including those
airplanes affected by this AD. That AD requires incorporation of the
modification program discussed previously. Paragraph (e) of this final
rule has been revised to indicate that installation of a terminating
modification in accordance with AD 95-10-16, amendment 39-9233,
constitutes terminating action for the requirements of this AD.
After careful review of the available data, including the comment
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the change previously
described. The FAA has determined that this change will neither
increase the economic burden on any operator nor increase the scope of
the AD.
There are approximately 35 Model 747SP series airplanes of the
affected design in the worldwide fleet. The FAA estimates that 11
airplanes of U.S. registry will be affected by this AD. The FAA
estimates that it will take approximately 22 work hours per airplane to
accomplish the required inspections (between front spar stations 628
and 675) specified in this AD, and that the average labor rate is $60
per work hour. Based on these figures, the total cost impact of the AD
on U.S. operators is estimated to be $14,520, or $1,320 per airplane.
The total 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 terminating modification
that is provided by this AD action, it will take approximately 644 work
hours to accomplish it, at an average labor rate of $60 per work hour.
The cost of required parts will be $21,800. Based on these figures, the
total cost impact of the terminating modification will be $60,440 per
airplane.
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. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13-- [Amended]
2. Section 39.13 is amended by removing amendment 39-6702 (55 FR
33279, August 15, 1990), and by adding a new airworthiness directive
(AD), amendment 39-9279, to read as follows:
95-12-26 BOEING: Amendment 39-9279. Docket 94-NM-120-AD. Supersedes
AD 90-17-18, Amendment 39-6702.
Applicability: Model 747SP series airplanes; variable numbers
RG001 through RG142 inclusive, and RG171 through RG222 inclusive;
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 use the authority
provided in paragraph (f) of this AD to request approval from the
FAA. This approval may address either no action, if the current
configuration eliminates the unsafe condition; or different actions
necessary to address the unsafe condition described in this AD. Such
a request should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent fuel leakage onto an engine and a resultant fire,
accomplish the following:
(a) For airplanes on which the ``terminating modification''
[between front spar station (FSS) 640 and FSS 670] specified in
Boeing Alert Service Bulletin 747-57A2259, dated February 15, 1990;
or Revision 1, dated September 6, 1990; has not been accomplished:
Within the next 6 months after September 21, 1990 (the effective
date
[[Page 34109]]
of AD 90-17-18, amendment 39-6702), perform a visual and an ultrasonic
inspection of the front spar web between FSS 636 and FSS 675, in
accordance with Boeing Alert Service Bulletin 747-57A2259, dated
February 15, 1990; or Revision 1, dated September 6, 1990. If no
crack is found, repeat these inspections at intervals not to exceed
1,000 landings until the inspections required by paragraph (b) of
this AD are accomplished.
(b) For airplanes on which the ``terminating modification''
[between FSS 640 and FSS 670] specified in Boeing Alert Service
Bulletin 747-57A2259, dated February 15, 1990; or Revision 1, dated
September 6, 1990; has not been accomplished: Prior to the
accumulation of 4,000 total landings on the airplane, or within 6
months after the effective date of this AD, whichever occurs later,
perform the inspections specified in paragraphs (b)(1), (b)(2), and
(b)(3) of this AD to detect cracks in the web between FSS 628 and
FSS 675, in accordance with Boeing Alert Service Bulletin 747-
57A2259, Revision 2, dated June 9, 1994. Accomplishment of these
inspections terminates the repetitive inspection requirement of
paragraph (a) of this AD. If no crack is found, repeat these
inspections thereafter at intervals not to exceed 1,000 landings.
(1) Perform an ultrasonic inspection in the web under the upper
and lower chord footprints; and
(2) Perform a high frequency eddy current inspection in the web
in an area one inch below the upper chord and one inch above the
lower chord footprints; and
(3) Perform a detailed visual inspection in the forward face of
the web of the wing front spar at fastener locations in the web-to-
stiffeners and web-to-rib posts.
(c) For airplanes on which the ``terminating modification''
specified in Boeing Alert Service Bulletin 747-57A2259, dated
February 15, 1990; or Revision 1, dated September 6, 1990; has been
accomplished: Prior to the accumulation of 4,000 total landings on
the airplane, or within 6 months after the effective date of this
AD, whichever occurs later, perform the inspections specified in
paragraphs (c)(1), (c)(2), and (c)(3) of this AD to detect cracks in
the web between FSS 628 and FSS 636, in accordance with Boeing Alert
Service Bulletin 747-57A2259, Revision 2, dated June 9, 1994. If no
crack is found, repeat these inspections thereafter at intervals not
to exceed 1,000 landings.
(1) Perform an ultrasonic inspection of the web under the upper
and lower chord footprints; and
(2) Perform a high frequency eddy current inspection of the web
in an area one inch below the upper chord and one inch above the
lower chord footprints; and
(3) Perform a detailed visual inspection of the forward face of
the web of the wing front spar at fastener locations in the web-to-
stiffeners and web-to-rib posts.
(d) If any crack is found during any inspection required by this
AD, prior to further flight, accomplish a terminating modification
(between FSS 623 and FSS 670) in accordance with Boeing Alert
Service Bulletin 747-57A2259, Revision 2, dated June 9, 1994; or in
accordance with a method approved by the Manager, Seattle Aircraft
Certification Office (ACO), FAA, Transport Airplane Directorate.
(e) Modification of the wing front spar web between FSS 623 and
FSS 670 in accordance with Boeing Alert Service Bulletin 747-
57A2259, Revision 2, dated June 9, 1994; or in accordance with a
method approved by the Manager, Seattle ACO; or in accordance with
AD 95-10-16, amendment 39-9233; constitutes terminating action for
the requirements of this AD.
(f) 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, FAA, Transport
Airplane Directorate. 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 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(g) 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.
(h) The inspections and modification shall be done in accordance
with Boeing Alert Service Bulletin 747-57A2259, dated February 15,
1990; or Boeing Alert Service Bulletin 747-57A2259, Revision 1,
dated September 6, 1990; or Boeing Alert Service Bulletin Revision
2, dated June 9, 1994; as applicable. 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.
(i) This amendment becomes effective on July 31, 1995. Issued in
Renton, Washington, on June 9, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-14631 Filed 6-29-95; 8:45 am]
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