[Federal Register Volume 65, Number 25 (Monday, February 7, 2000)]
[Rules and Regulations]
[Pages 5742-5744]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-2413]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-252-AD; Amendment 39-11551; AD 2000-02-33]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-400 Series Airplanes 
Equipped With General Electric CF6-80C2 Series Engines

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 various inspections and functional tests to detect 
discrepancies of the thrust reverser control and indication system, and 
correction of any discrepancy found. This amendment is prompted by 
reports indicating that several center drive units (CDU) were returned 
to the manufacturer of the CDU's because of low holding torque of the 
CDU cone brake. The actions specified by this AD are intended to ensure 
the integrity of the fail safe features of the thrust reverser system 
by preventing possible failure modes in the thrust reverser control 
system that can result in inadvertent deployment of a thrust reverser 
during flight.

DATES:  Effective March 13, 2000.

[[Page 5743]]

    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 13, 2000.

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:  Holly Thorson, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-1357; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION:  A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 94-15-05, 
amendment 39-8976 (59 FR 37655, July 25, 1994), which is applicable to 
all Boeing Model 747-400 series airplanes, was published in the Federal 
Register on June 22, 1999 (64 FR 33229). The action proposed to require 
various inspections and functional tests to detect discrepancies of the 
thrust reverser control and indication system, and correction of any 
discrepancy found.

Explanation of Changes to the Proposed Rule

    The original notice of proposed rulemaking (NPRM) proposed to 
supersede AD 94-15-05, which is applicable to Boeing Model 747-400 
series airplanes equipped with either Pratt & Whitney PW4000 series 
engines; Rolls-Royce RB211-524G/H series engines; or General Electric 
(GE) CF6-80C2 series engines. Since the issuance of that NPRM, the FAA 
has determined that, in order to simplify compliance, each engine type 
should be addressed in separate rulemaking actions that do not 
supersede AD 94-15-05. Therefore, the FAA currently is developing 
separate rulemaking to address the Pratt & Whitney PW4000 series 
engines, and Rolls-Royce RB211-524G/H series engines referenced in the 
original NPRM, and has revised the applicability in this final rule to 
address the requirements for the GE CF6-80C2 series engines only. In 
addition, paragraphs (a) through (d) of the original NPRM are not 
restated in this final rule. The cost impact information, below, also 
has been revised accordingly.

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 for Credit for Previously Accomplished Work

    One commenter requests credit for accomplishing the thrust reverser 
center drive unit (CDU) cone brake test during production. The 
commenter states that the tests were accomplished previously in 
accordance with methods equivalent to those described in Boeing Service 
Bulletins 747-78A2166 and 747-78A2113.
    The FAA concurs with the commenter's request that accomplishment of 
the test during production is acceptable for compliance with the 
applicable test requirement in the final rule. ``Note 2'' has been 
added to the final rule to provide credit for accomplishment of the 
test during production.
    One commenter requests credit for accomplishing the modification to 
install the third locking system of the thrust reversers during 
production. The commenter states that all Model 747-400 series 
airplanes, line numbers 1061 and subsequent, equipped with GE CF6-80C2 
series engines, had a third locking system installed during production 
in accordance with Production Revision Record (PRR) 80452-102, and were 
not modified in accordance with Boeing Service Bulletin 747-78-2151 
(which is a retrofit action applicable to line numbers 700 through 1060 
inclusive).
    The FAA concurs with the commenter's request. The FAA has 
determined that the production modification is technically equivalent 
to the modification described in Boeing Service Bulletin 747-78-2151; 
therefore, paragraphs (a)(1) and (a)(2) of this final rule [referenced 
as paragraphs (e)(1) and (e)(2) in the proposed rule], have been 
revised accordingly. In addition, ``Note 3'' has been added to the 
final rule for further clarification.

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.

Interim Action

    This is considered to be interim action. The manufacturer has 
advised that it currently is developing a modification that will 
positively address the unsafe condition addressed by this AD. Once this 
modification is developed, approved, and available, the FAA may 
consider additional rulemaking.

Cost Impact

    There are approximately 146 Model 747-400 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 16 
airplanes of U.S. registry will be affected by this AD.
    The new actions required by this AD will not add any additional 
economic burden on affected operators, other than the costs that are 
associated with repeating the functional test of the cone brake at 
reduced intervals (at intervals not to exceed 650 hours time-in-service 
for thrust reversers that have not been modified.) That test requires 
approximately 12 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 functional test required by this AD on U.S. operators is 
estimated to be $11,520, or $720 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the current 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 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

[[Page 5744]]

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:

2000-02-33  Boeing: Amendment 39-11551. Docket 98-NM-252-AD.

    Applicability: Model 747-400 series airplanes equipped with 
General Electric CF6-80C2 series engines, 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 (d)(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 ensure the integrity of the fail safe features of the thrust 
reverser system by preventing possible failure modes in the thrust 
reverser control system that can result in inadvertent deployment of 
a thrust reverser during flight, accomplish the following:

Repetitive Functional Tests

    (a) Within 1,000 hours time-in-service after the most recent 
test of the center drive unit (CDU) cone brake performed in 
accordance with paragraph (b)(1) of AD 94-15-05, amendment 39-8976; 
or within 650 hours time-in-service after the effective date of this 
AD, whichever occurs first: Perform a functional test to detect 
discrepancies of the CDU cone brake on each thrust reverser, in 
accordance with Boeing Service Bulletin 747-78A2166, Revision 1, 
dated October 9, 1997; or the applicable section of paragraph III.A. 
of the Accomplishment Instructions of Boeing Service Bulletin 747-
78A2113, Revision 2, dated June 8, 1995, or Revision 3, dated 
September 11, 1997.

    Note 2:  Accomplishment of the CDU cone brake test during 
production in accordance with Production Revision Record (PRR) 
80452-102 prior to the effective date of this AD is considered 
acceptable for compliance with the test required by paragraph (a) of 
this AD.

    (1) For Model 747-400 series airplanes equipped with thrust 
reversers that have not been modified in accordance with Boeing 
Service Bulletin 747-78-2151 or a production equivalent: Repeat the 
functional test of the CDU cone brake thereafter at intervals not to 
exceed 650 hours time-in-service.
    (2) For Model 747-400 series airplanes equipped with thrust 
reversers that have been modified in accordance with Boeing Service 
Bulletin 747-78-2151 or a production equivalent: Repeat the 
functional test of the CDU cone brake thereafter at intervals not to 
exceed 1,000 hours time-in-service.

    Note 3:  Model 747-400 series airplanes, line numbers 1061 and 
subsequent, equipped with GE CF6-80C2 engines, had a third locking 
system installed during production in accordance with Production 
Revision Record (PRR) 80452-102, and were not modified in accordance 
with Boeing Service Bulletin 747-78-2151 (which is a retrofit action 
for airplanes having line numbers 700 through 1060 inclusive).

Terminating Action

    (b) Accomplishment of the functional test of the CDU cone brake, 
as specified in paragraph (a) of this AD, constitutes terminating 
action for the repetitive tests of the CDU cone brake required by 
paragraph (b)(1) of AD 94-15-05.

Corrective Action

    (c) If any functional test required by paragraph (a) of this AD 
cannot be successfully performed as specified in the referenced 
service bulletin, or if any discrepancy is detected during any 
functional test required by paragraph (a) of this AD, accomplish 
either paragraph (c)(1) or (c)(2) of this AD.
    (1) Prior to further flight, repair in accordance with Boeing 
Service Bulletin 747-78A2166, Revision 1, dated October 9, 1997; or 
Boeing Service Bulletin 747-78A2113, Revision 2, dated June 8, 1995, 
or Revision 3, dated September 11, 1997, Or,
    (2) The airplane may be operated in accordance with the 
provisions and limitations specified in the operator's FAA-approved 
MEL, provided that no more than one thrust reverser on the airplane 
is inoperative.

Alternative Methods of Compliance

    (d)(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 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.
    (2) Alternative methods of compliance for the functional test of 
the Thrust Reverser Actuation System (TRAS) lock for Model 747-400 
series airplanes powered by General Electric CF6-80C2 series engines 
that have been modified in accordance with Boeing Service Bulletin 
747-78-2151, or production equivalent, approved previously in 
accordance with AD 94-15-05, amendment 39-8976, are considered to be 
approved as alternative methods of compliance with this AD.

    Note 4:  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

    (e) 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

    (f) Except as provided by paragraph (c)(2) of this AD, the 
actions shall be done in accordance with Boeing Service Bulletin 
747-78A2166, Revision 1, dated October 9, 1997; Boeing Service 
Bulletin 747-78A2113, Revision 2, dated June 8, 1995, and Boeing 
Service Bulletin 747-78A2113, Revision 3, dated September 11, 1997. 
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.
    (g) This amendment becomes effective on March 13, 2000.

    Issued in Renton, Washington, on January 28, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-2413 Filed 2-4-00; 8:45 am]
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