[Federal Register Volume 65, Number 248 (Tuesday, December 26, 2000)]
[Rules and Regulations]
[Pages 81329-81331]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-32406]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-326-AD; Amendment 39-12046; AD 2000-25-11]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-400 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 certain Boeing Model 747-400 series airplanes, that 
requires repetitive inspections to detect fatigue cracking of the 
longeron splice fittings at stringer 11 on the left and right sides at 
body station 2598, and various follow-on actions. The actions specified 
by this AD are necessary to detect and correct fatigue cracking of the 
longeron splice fittings and subsequent damage to adjacent structure. 
Such damage could result in the inability of the structure to carry 
horizontal stabilizer flight loads, and consequent reduced 
controllability of the horizontal stabilizer. This action is intended 
to address the identified unsafe condition.

DATES: Effective January 30, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of January 30, 2001.

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: Rick Kawaguchi, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-1153; 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 Model 747-400 
series airplanes was published in the Federal Register on June 28, 2000 
(65 FR 39828). That action proposed to require repetitive inspections 
to detect fatigue cracking of the longeron splice fittings at stringer 
11 on the left and right sides at body station 2598, and various 
follow-on 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.

Support for the Proposed Rule

    One commenter supports the proposed rule.

Request to Reference New Service Bulletin

    One commenter requests that the FAA revise the proposed rule to 
reference a new service bulletin, Boeing Alert Service Bulletin 747-
53A2419, Revision 1, dated September 21, 2000. (The proposed rule 
referenced Boeing Alert Service Bulletin 747-53A2419, dated December 
17, 1998, as the appropriate source of service information for certain 
proposed actions.) The commenter provides no justification for its 
request.
    The FAA concurs with the commenter's request. Since the issuance of 
the proposed rule, the FAA has reviewed and approved Revision 1 of the 
service bulletin, including Appendix A. Revision 1 clarifies certain 
instructions and revises the effectivity listing to show changes in 
airplane operators. (No additional airplanes are added to the 
effectivity listing of Revision 1.) Therefore, the FAA has revised the 
applicability statement and paragraphs (a), (b)(1), (b)(2), and (c) of 
this final rule to reference Revision 1 of the service bulletin as the 
appropriate source of service information for the actions required by 
those paragraphs. The FAA also has added a new Note 2 to this AD (and 
reordered subsequent notes accordingly) to state that accomplishment of 
the actions required by this AD in accordance with the original issue 
of the service bulletin is acceptable for compliance with this AD.

Request To Follow Service Bulletin Instructions

    One commenter requests that the FAA revise the proposed AD to 
reflect the service bulletin instructions for removal and replacement 
of the longeron splice fittings. The commenter notes that the service 
bulletin allows for removal and replacement of only those splice 
fittings that are cracked, provided that repetitive inspections of the 
remaining, uncracked, fittings continue. The proposed AD would require 
removal and replacement of all four fittings on the affected side if a 
single fitting is found to be cracked.
    The FAA does not concur with the commenter's request. As explained 
in the ``Differences Between Proposed Rule and Alert Service Bulletin'' 
section of the proposal, the FAA finds it appropriate to mandate 
replacement of all longeron splice fittings on the affected side of the 
airplane if one fitting is found to be cracked. As pointed out in that 
same section of the proposal, the service bulletin recommends 
replacement of all four fittings on one side of the airplane at the 
same time (see Flag Note 1 of Figure 1 of the service bulletin). No 
change to the final rule is necessary in this regard.

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 previously 
described. 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 490 Model 747-400 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 59 
airplanes of U.S. registry will be affected by this AD.
    It will take approximately 2 work hours (1 hour per each side) 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 
this inspection on U.S. operators is estimated to be $7,080, or $120 
per airplane, per inspection cycle.

[[Page 81330]]

    It will take approximately 12 work hours (6 hours per each side) 
per airplane to accomplish the required rework or replacement, at an 
average labor rate of $60 per work hour. Required parts will cost 
between $731 and $7,906 per airplane. Based on these figures, the cost 
impact of this rework or replacement on U.S. operators is estimated to 
be between $1,451 and $8,626 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.

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 adding the following new 
airworthiness directive:

2000-25-11  Boeing: Amendment 39-12046. Docket 99-NM-326-AD.

    Applicability: Model 747-400 series airplanes, as listed in 
Boeing Alert Service Bulletin 747-53A2419, Revision 1, dated 
September 21, 2000; 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 (e) 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 detect and correct fatigue cracking of the longeron splice 
fittings and subsequent damage to adjacent structure, which could 
result in the inability of the structure to carry horizontal 
stabilizer flight loads, and consequent reduced controllability of 
the horizontal stabilizer; accomplish the following:

Initial Detailed Visual Inspection

    (a) Perform a detailed visual inspection to detect cracking of 
the longeron fittings at stringer 11, on the left and right sides at 
body station 2598, at the later of the times specified in paragraphs 
(a)(1) and (a)(2) of this AD, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-53A2419, Revision 
1, including Appendix A, dated September 21, 2000.
    (1) Inspect prior to the accumulation of 17,000 total flight 
cycles or 63,000 total flight hours, whichever occurs first.
    (2) Inspect within 24 months after the effective date of this 
AD.

    Note 2: Inspections, rework, and replacements accomplished prior 
to the effective date of this AD in accordance with Boeing Alert 
Service Bulletin 747-53A2419, dated December 17, 1998, are 
considered acceptable for compliance with the applicable action 
specified in this amendment.


    Note 3: Where there are differences between the AD and the 
service bulletin, the AD prevails.


    Note 4: For the purposes of this AD, a detailed visual 
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.''

Rework/Replacement/Repetitive Inspections

    (b) If no cracking is detected during the inspection required by 
paragraph (a) of this AD, accomplish the requirements of either 
paragraph (b)(1), (b)(2), or (b)(3) of this AD.
    (1) Prior to further flight, rework all four longeron splice 
fittings on the left and right sides at body station 2598, in 
accordance with Part 3 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 747-53A2419, Revision 1, including Appendix 
A, dated September 21, 2000. Repeat the inspection required by 
paragraph (a) of this AD one time at the later of the times 
specified in paragraphs (b)(1)(i) and (b)(1)(ii) of this AD, and 
thereafter at intervals not to exceed 3,000 flight cycles or 18,000 
flight hours, whichever occurs first.
    (i) For airplanes on which the rework is accomplished prior to 
the accumulation of 7,000 total flight cycles and prior to the 
accumulation of 25,000 total flight hours: Inspect within 20,000 
flight cycles or 72,000 flight hours after rework, whichever occurs 
first.
    (ii) For airplanes on which the rework is accomplished at or 
after the accumulation of 7,000 total flight cycles, or 25,000 total 
flight hours: Inspect within 10,000 flight cycles or 36,000 flight 
hours after rework, whichever occurs first.
    (2) Prior to further flight, replace all four longeron splice 
fittings on the left and right sides at body station 2598 with new 
fittings, in accordance with Part 2 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-53A2419, Revision 
1, including Appendix A, dated September 21, 2000. Repeat the 
inspection required by paragraph (a) of this AD one time within 
20,000 flight cycles or 72,000 flight hours after the replacement, 
whichever occurs first; and thereafter at intervals not to exceed 
3,000 flight cycles or 18,000 flight hours, whichever occurs first.
    (3) Repeat the inspection required by paragraph (a) of this AD 
at intervals not to exceed 3,000 flight cycles or 18,000 flight 
hours, whichever occurs first.

Corrective Action/Repetitive Inspections

    (c) If any cracking is detected during any inspection required 
by paragraph (a) or (b)(3) of this AD, prior to further flight: 
Replace all four longeron splice fittings on the affected side in 
accordance with Part 2 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 747-53A2419, Revision 1, including Appendix 
A, dated September 21, 2000. Repeat the inspection on the affected 
side as required by paragraph (a) of this AD one time within 20,000 
flight cycles or 72,000 flight hours after the replacement,

[[Page 81331]]

whichever occurs first; and thereafter at intervals not to exceed 
3,000 flight cycles or 18,000 flight hours, whichever occurs first.
    (d) If any cracking is detected during any inspection required 
by paragraph (b)(1), (b)(2), or (c) of this AD, repair in accordance 
with a method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA; or in accordance with data meeting 
the type certification basis of the airplane approved by a Boeing 
Company Designated Engineering Representative (DER) 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 approval letter must specifically 
reference this AD.

    Note 5: There is no terminating action currently available for 
the inspections required by this AD.

Alternative Methods of Compliance

    (e) 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 6: 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

    (f) Special flight permits may be issued in accordance with 
Secs. 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

    (g) Except as provided by paragraph (d) of this AD, the actions 
shall be done in accordance with Boeing Alert Service Bulletin 747-
53A2419, Revision 1, including Appendix A, dated September 21, 2000. 
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

    (h) This amendment becomes effective on January 30, 2001.

    Issued in Renton, Washington, on December 14, 2000.
Dorenda D. Baker,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-32406 Filed 12-22-00; 8:45 am]
BILLING CODE 4910-13-U