Airworthiness Directives; Boeing Model 747-400 Series Airplanes

[Federal Register Volume 63, Number 227 (Wednesday, November 25, 1998)]
[Rules and Regulations]
[Pages 65054-65055]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-31324]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-13-AD; Amendment 39-10913; AD 98-24-26]
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 replacing the cam assembly, cam bellcrank assembly, and thrust 
reverser control switch actuator on all four thrust levers with new 
components. This amendment is prompted by a report of an uncommanded 
automatic retraction of the leading edge flaps during takeoff. The 
actions specified by this AD are intended to prevent such uncommanded 
automatic retraction, which would seriously degrade liftoff and climb 
capabilities, and could result in near-stall conditions at a critical 
phase of the flight.

DATES: Effective December 30, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of December 30, 1998.

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: Frank van Leynseele, Aerospace 
Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington; 
telephone (206) 227-2671; fax (206) 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 April 14, 
1997 (62 FR 18063). That action proposed to require replacing the cam 
assembly, cam bellcrank assembly, and thrust reverser control switch 
actuator on all four thrust levers with new components.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request To Cite the Latest Service Information

    Three commenters request that the proposed rule be revised to 
reflect the latest revision of Boeing Alert Service Bulletin 747-
27A2356; the original issue of that service bulletin was referenced in 
the proposal as the appropriate source of service information.
    The FAA concurs with the commenters' request to reference the 
latest revision of the service bulletin. The FAA has reviewed and 
approved Boeing Service Bulletin 747-27A2356, Revision 1, dated August 
13, 1998. That

[[Page 65055]]

revision of the service bulletin provides a correction to certain part 
numbers of the cam bellcrank assemblies and clarifies certain part-
marking instructions. In addition, Revision 1 of the service bulletin 
describes a revision of the operating position of the reverse thrust 
isolation valve switches in the thrust levers. The FAA has revised the 
final rule to reference Boeing Service Bulletin 747-27A2356, Revision 
1, dated August 13, 1998, as the appropriate source of service 
information. The FAA has determined that requiring the replacements to 
be performed in accordance with Revision 1 of the service bulletin will 
not pose an additional burden on any operator.

Request To Revise the Cost Impact Information

    One commenter, the manufacturer, requests that the cost impact 
information be corrected to reflect that 46 airplanes of U.S. registry 
will be affected by this AD, rather than the 35 airplanes estimated in 
the proposal. The FAA concurs and has revised the cost impact 
information accordingly.

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 394 Boeing Model 747-400 series airplanes 
of the affected design in the worldwide fleet. The FAA estimates that 
46 airplanes of U.S. registry will be affected by this AD, that it will 
take approximately 8 work hours per airplane to accomplish the required 
actions, and that the average labor rate is $60 per work hour. Required 
parts would cost between $3,412 and $4,740 per airplane. Based on these 
figures, the cost impact of the AD is estimated to be between $179,032 
and $240,120, or between $3,892 and $5,220 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.

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:

98-24-26  Boeing: Amendment 39-10913. Docket 97-NM-13-AD.

    Applicability: Model 747-400 series airplanes, line positions 
696 through 1090 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 request approval for an 
alternative method of compliance in accordance with paragraph (b) 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 prevent uncommanded automatic retraction of the leading edge 
flaps during takeoff, which would seriously degrade liftoff and 
climb capabilities, and could result in near-stall conditions, 
accomplish the following:
    (a) Within 18 months after the effective date of this AD, 
accomplish the requirements of paragraph (a)(1) or (a)(2) of this 
AD, as applicable, in accordance with Boeing Service Bulletin 747-
27A2356, Revision 1, dated August 13, 1998.
    (1) For Groups 1 and 2 airplanes, as listed in the service 
bulletin: Replace the cam assembly, cam bellcrank assembly, and 
thrust reverser control switch actuator on all four thrust levers 
with new components.
    (2) For Groups 3 and 4 airplanes, as listed in the service 
bulletin: Replace the cam bellcrank assembly and thrust reverser 
control switch actuator on all four thrust levers with new 
components.
    (b) 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 Aircraft Certification 
Office (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.

    (c) 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.
    (d) The actions shall be done in accordance with Boeing Service 
Bulletin 747-27A2356, Revision 1, dated August 13, 1998. 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.
    (e) This amendment becomes effective on December 30, 1998.

    Issued in Renton, Washington on November 18, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-31324 Filed 11-24-98; 8:45 am]
BILLING CODE 4910-13-U

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