[Federal Register Volume 67, Number 231 (Monday, December 2, 2002)]
[Rules and Regulations]
[Pages 71450-71452]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-30026]


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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]
BILLING CODE 4910-13-P