[Federal Register: December 2, 2002 (Volume 67, Number 231)]
[Rules and Regulations]
[Page 71450-71452]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr02de02-2]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2002-NM-24-AD; Amendment 39-12965; AD 2002-23-21]
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 supersedes an existing airworthiness directive
(AD), applicable to certain Boeing Model 747 series airplanes, that
currently requires inspection of the flap tracks of the wing trailing
edge flaps for adequate cadmium plating and for corrosion of certain
bolt holes of the fail-safe bar, and plating of such holes, if
necessary. This amendment also requires post-modification inspections
of certain bolt holes of the fail-safe bar of the flap tracks of the
wing trailing edge flaps for discrepancies, and corrective actions, if
necessary. This amendment is prompted by reports of corrosion and
cracks found in certain bolt holes reworked according to the existing
AD. The actions specified by this AD are intended to find and fix
discrepancies of the bolt holes, which could result in fracture of the
flap track, separation of the flap, and consequent loss of control of
the airplane. This action is intended to address the identified unsafe
condition.
DATES: Effective January 6, 2003.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of January 6, 2003.
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 Anderson, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, 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) by superseding AD 91-03-17,
amendment 39-6884 (56 FR 4534, February 5, 1991), which is applicable
to certain Boeing Model 747 series airplanes, was published in the
Federal Register on July 1, 2002 (67 FR 44116). The action proposed to
continue to require inspection of the flap tracks of the wing trailing
edge flaps for adequate cadmium plating and for corrosion of certain
bolt holes of the fail-safe bar, and plating of such holes, if
necessary. That action also proposed to require post-modification
inspections of certain bolt holes of the fail-safe bar of the flap
tracks of the wing trailing edge flaps for discrepancies, and
corrective actions, if necessary.
Comments
Interested persons have been afforded an opportunity to participate
in the making of this amendment. No comments were submitted in response
to the proposal or the FAA's determination of the cost to the public.
Conclusion
The FAA has determined that air safety and the public interest
require the adoption of the rule as proposed.
[[Page 71451]]
Cost Impact
There are approximately 553 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 169 airplanes of U.S. registry
will be affected by this AD.
The actions that are currently required by AD 91-03-17 take
approximately 50 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. Based on these figures, the cost
impact of the currently required actions is estimated to $3,000 per
airplane.
The borescope inspection required by this AD action will take
approximately 32 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. Based on these figures, the cost
impact of the borescope inspection required by this AD on U.S.
operators is estimated to be $324,480, or $1,920 per airplane.
The cost impact figures discussed above are 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.
Should an operator be required to accomplish the eddy current
inspection, it takes approximately 40 work hours per airplane to
accomplish the inspection, at an average labor rate of $60 per work
hour. Based on these figures, the cost impact of this inspection is
estimated to be $2,400 per airplane.
Should an operator be required to accomplish the modification of
the bolt holes, it takes approximately 256 work hours per airplane to
accomplish the modification, at an average labor rate of $60 per work
hour. Based on these figures, the cost impact of the modification is
estimated to be $15,360 per airplane.
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.
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 removing amendment 39-6884 (56 FR
4534, February 5, 1991), and by adding a new airworthiness directive
(AD), amendment 39-12965, to read as follows:
2002-23-21 Boeing: Amendment 39-12965. Docket 2002-NM-24-AD.
Supersedes
AD 91-03-17, Amendment 39-6884.
Applicability: Model 747 series airplanes, as listed in Boeing
Service Bulletin 747-57-2256, Revision 3, dated June 21, 2001;
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 (f)(1)
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.
To find and fix discrepancies of certain bolt holes of the fail-
safe bar of the flap tracks of the wing trailing edge flaps, which
could result in separation of the flap and consequent loss of
control of the airplane, accomplish the following:
Restatement of Certain Requirements of AD 91-03-17
Inspections
(a) Prior to the accumulation of 30,000 total flight hours, or 8
years time-in-service on current production flap tracks, whichever
is first; or within 2,000 flight cycles after March 11, 1991 (the
effective date of AD 91-03-17, amendment 39-6884); whichever is
later: Perform a borescope inspection of the forward four bolt holes
on each side of the affected trailing edge flap tracks for corrosion
and adequate cadmium plating, in accordance with the procedures
specified in Boeing Service Bulletin 747-57-2256, dated March 8,
1990; Revision 1, dated November 15, 1990; Revision 2, dated March
5, 1992; or Revision 3, dated June 21, 2001. If the cadmium plating
is adequate, as specified in the service bulletin, and no corrosion
or cracks are found, no further action is required for this
paragraph. If the cadmium plating is not adequate, or if corrosion
exists in any bolt hole, prior to further flight, conduct an eddy
current inspection of the bolt hole for cracks, in accordance with
the service bulletin. After the effective date of this AD only
Revision 3 of the service bulletin may be used.
Corrective Actions
(b) If the cadmium plating is not adequate and no corrosion or
cracks are found during the inspection required by paragraph (a) of
this AD: Within 1,000 flight cycles after accomplishment of the
inspection required by paragraph (a) of this AD, cadmium plate the
affected bolt holes in accordance with Boeing Service Bulletin 747-
57-2256, dated March 8, 1990; Revision 1, dated November 15, 1990;
Revision 2, dated March 5, 1992; or Revision 3, dated June 21, 2001;
and conduct the inspections of the affected track as specified in
paragraphs (b)(1), (b)(2), and (b)(3) of this AD, in accordance with
the service bulletin. Restoration of the cadmium plating terminates
the inspections required by this paragraph.
Inspections
(1) Within 50 flight cycles after accomplishment of the
inspection required by paragraph (a) of this AD: Perform a close
visual inspection of each side of the track, at the lower chord, for
cracks emanating from the forward four fail-safe bar bolt holes, and
repeat the inspection thereafter at intervals not to exceed 50
flight cycles.
(2) Within 250 flight cycles after accomplishment of the
inspection required by paragraph (a) of this AD: Perform an eddy
current inspection for cracks of the bolt holes, and repeat the
inspection thereafter at intervals not to exceed 250 flight cycles.
(3) Prior to each flight on which a fifth engine is to be
carried, perform a close visual inspection of each side of the
track, at the lower chord, for cracks emanating from the forward
four fail-safe bar bolt holes.
[[Page 71452]]
New Requirements of this AD
Cadmium Plating Applied During Production
(c) For airplanes on which cadmium plating of the forward four
bolt holes was applied during production: No further action is
required by this AD. If operator records indicate that during the
inspection required by paragraph (a) of this AD cadmium plating was
applied during production (not during rework or replating), no
further action is required by this AD. (Indications of rework
include oversized fasteners and/or fasteners with repair sleeves,
and/or flap track dash numbers that have been changed per the
service bulletin.)
Compliance Time for Borescope Inspection
(d) For airplanes on which cadmium plating of the forward four
bolt holes was not applied during production: Do the action required
by paragraph (e) of this AD at the later of the times given in
paragraphs (d)(1) and (d)(2) of this AD.
(1) Within 2 years or 2,000 flight cycles after the effective
date of this AD, whichever is first; or
(2) Within 6 years after doing the initial bolt hole rework per
AD 91-03-17.
Borescope Inspection
(e) Do a borescope inspection of the forward four bolt holes on
each side of the fail-safe bar of the flap tracks of the trailing
edge flaps for discrepancies (corrosion, cracks, damaged cadmium
plating), per Part 2 of the Work Instructions of Boeing Service
Bulletin 747-57-2256, Revision 3, dated June 21, 2001. Then, do the
actions specified in paragraph (e)(1), (e)(2), or (e)(3) of this AD,
as applicable, and repeat the borescope inspection every 8 years or
8,000 flight cycles, whichever is first. Accomplishment of the
actions specified in this paragraph terminates the requirements of
paragraph (a) of this AD.
Corrective Actions
(1) If the cadmium plating is damaged, but no corrosion or
cracking is found: Before further flight, do the eddy current
inspection specified in and per Part 2.F. of the Work Instructions
of the service bulletin. If no cracking is found, before further
flight, cadmium plate the affected bolt holes per Part 2.F. of the
Work Instructions of the service bulletin.
(2) If any corrosion is found, before further flight, rework the
affected bolt holes as specified in and per Part 2.G. of the Work
Instructions of the service bulletin.
(3) If any cracking is found, before further flight, repair per
a method approved by the Manager, Seattle Aircraft Certification
Office (ACO), 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 by the
Manager, Seattle ACO, as required by this paragraph, the Manager's
approval letter must specifically reference this AD.
Alternative Methods of Compliance
(f)(1) 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.
(2) Alternative methods of compliance, approved previously in
accordance with AD 91-03-17, amendment 39-6884, are approved as
alternative methods of compliance with paragraphs (a) and (b) of
this AD.
Note 2: 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
(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.
Incorporation by Reference
(h) Except as provided by paragraph (e)(3) of this AD, the
actions shall be done in accordance with Boeing Service Bulletin
747-57-2256, dated March 8, 1990; Boeing Service Bulletin 747-57-
2256, Revision 1, dated November 15, 1990; Boeing Service Bulletin
747-57-2256, Revision 2, dated March 5, 1992; or Boeing Service
Bulletin 747-57-2256, Revision 3, dated June 21, 2001; as
applicable. This incorporation by reference is 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
(i) This amendment becomes effective on January 6, 2003.
Issued in Renton, Washington, on November 19, 2002.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 02-30026 Filed 11-29-02; 8:45 am]
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