[Federal Register Volume 64, Number 139 (Wednesday, July 21, 1999)]
[Rules and Regulations]
[Pages 39003-39005]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-18198]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-247-AD; Amendment 39-11227; AD 99-15-08]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-200 and -300 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 supersedes an existing airworthiness directive 
(AD), applicable to certain Boeing Model 747-200 and -300 series 
airplanes, that currently 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 reduces the repetitive interval for one certain functional 
test. 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 August 25, 1999.
    The incorporation by reference of Boeing Service Bulletin 747-
78A2166, Revision 1, dated October 9, 1997, as listed in the 
regulations, is approved by the Director of the Federal Register as of 
August 25, 1999.
    The incorporation by reference of Boeing Alert Service Bulletin 
747-78A2130, dated May 26, 1994, was approved previously by the 
Director of the Federal Register as of April 13, 1995 (60 FR 13623, 
March 14, 1995).

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 95-06-01, 
amendment 39-9171 (60 FR 13623, March 14, 1995), which is applicable to 
certain Boeing Model 747-200 and -300 series airplanes, was published 
in the Federal Register on January 21, 1999 (64 FR 3226). The action 
proposed to continue to require various inspections and functional 
tests to detect discrepancies of the thrust reverser control and 
indication system, and correction of any discrepancy found. The action 
also proposed to reduce the repetitive interval for one certain 
functional test.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the single comment received.
    The commenter supports the proposed rule.

Explanation of Change to the Final Rule

    In the notice of proposed rulemaking (NPRM), the FAA proposed to 
require repetitive functional tests of the CDU cone brake on Model 747-
200 and -300 series airplanes, at intervals not to exceed 650 hours 
time-in-service, regardless of whether the airplane is equipped with 
thrust reversers modified in accordance with Boeing Service Bulletin 
747-78-2144. Since the issuance of the NPRM, the FAA has determined 
that a repetitive interval of 1,000 hours time-in-service would 
adequately ensure safety on airplanes equipped with thrust reversers 
modified in accordance with Boeing Service Bulletin 747-78-2144, 
Revision 1, dated April 11, 1996. This decision is based on the FAA's 
determination that frequent maintenance on such systems as the thrust 
reverser system could increase the risk of maintenance errors. Also, 
Boeing Service Bulletin 747-78-

[[Page 39004]]

2144, Revision 1, recommends functional tests at intervals not to 
exceed 1,000 hours time-in-service for thrust reversers that have been 
modified to incorporate a third locking device in accordance with that 
service bulletin. Performing the functional test of the cone brake at 
the same interval as the functional test of the third locking device 
would allow both thrust reverser tests to be scheduled and performed at 
the same time. Therefore, paragraph (d) of this final rule has been 
revised accordingly, and new paragraphs (d)(1) and (d)(2) have been 
added to this final rule.

Conclusion

    After careful review of the available data, including the comment 
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.

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 9 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 2 airplanes of U.S. registry 
will be affected by this AD.
    The 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 
rather than at intervals not to exceed 1,000 hours time-in-service). 
The current costs associated with AD 95-06-01 are reiterated in their 
entirety (as follows) for the convenience of affected operators.
    The actions that are currently required by AD 95-06-01, and 
retained in this AD, take approximately 33 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 on 
U.S. operators is estimated to be $3,960, or $1,980 per airplane, per 
inspection/test cycle.
    The cost impact figure discussed above is 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 removing amendment 39-9171 (60 FR 
13623, March 14, 1995), and by adding a new airworthiness directive 
(AD), amendment 39-11227, to read as follows:

99-15-08  Boeing: Amendment 39-11227. Docket 98-NM-247-AD. 
Supersedes AD 95-06-01, Amendment 39-9171.

    Applicability: Model 747-200 and -300 series airplanes equipped 
with General Electric Model CF6-80C2 series engines with Power 
Management Control engine controls, 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) 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:

Restatement of Requirements of AD 95-06-01

    (a) Within 90 days after April 13, 1995 (the effective date of 
AD 95-06-01, amendment 39-9171), perform tests of the position 
switch module and the cone brake of the center drive unit (CDU) on 
each thrust reverser, and perform an inspection to detect damage to 
the bullnose seal on the translating sleeve on each thrust reverser, 
in accordance with paragraphs III.A. through III.C. of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
78A2130, dated May 26, 1994. Repeat the tests and inspection 
thereafter at intervals not to exceed 1,000 hours time-in-service 
until the functional test required by paragraph (d) of this AD is 
accomplished.
    (b) Within 9 months after April 13, 1995, perform inspections 
and functional tests of the thrust reverser control and indication 
system in accordance with paragraphs III.D. through III.F., III.H., 
and III.I. of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-78A2130, dated May 26, 1994. Repeat these 
inspections and functional tests thereafter at intervals not to 
exceed 18 months.
    (c) If any of the inspections and/or functional tests required 
by paragraphs (a) and (b) of this AD cannot be successfully 
performed, or if any discrepancy is found during those inspections 
and/or functional tests, accomplish either paragraph (c)(1) or 
(c)(2) of this AD.
    (1) Prior to further flight, correct the discrepancy found, in 
accordance with Boeing Alert Service Bulletin 747-78A2130, dated May 
26, 1994. Or

[[Page 39005]]

    (2) The airplane may be operated in accordance with the 
provisions and limitations specified in an operator's FAA-approved 
Minimum Equipment List (MEL), provided that no more than one thrust 
reverser on the airplane is inoperative.

New Requirements of This AD

    (d) Within 1,000 hours time-in-service after the most recent 
test of the CDU cone brake performed in accordance with paragraph 
(a) of this AD, 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 paragraph III.B. 
of the Accomplishment Instructions of Boeing Alert Service Bulletin 
747-78A2130, dated May 26, 1994. Repeat the functional test 
thereafter at the interval specified in paragraph (d)(1) or (d)(2) 
of this AD, as applicable. Accomplishment of such functional test 
constitutes terminating action for the repetitive test of the CDU 
cone brake required by paragraph (a) of this AD.
    (1) For airplanes equipped with thrust reversers NOT modified in 
accordance with Boeing Service Bulletin 747-78-2144, Revision 1, 
dated April 11, 1996: Repeat the functional test at intervals not to 
exceed 650 hours time-in-service.
    (2) For airplanes equipped with thrust reversers modified in 
accordance with Boeing Service Bulletin 747-78-2144, Revision 1, 
dated April 11, 1996: Repeat the functional test at intervals not to 
exceed 1,000 hours time-in-service.
    (e) If any functional test required by paragraph (d) of this AD 
cannot be successfully performed, or if any discrepancy is found 
during any functional test required by paragraph (d) of this AD, 
accomplish either paragraph (e)(1) or (e)(2) of this AD.
    (1) Prior to further flight, correct the discrepancy found, in 
accordance with Boeing Service Bulletin 747-78A2166, Revision 1, 
dated October 9, 1997, or paragraph III.B. of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-78A2130, dated May 
26, 1994. 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

    (f) 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, 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.

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 paragraphs (c)(2) and (e)(2) of this 
AD, the actions shall be done in accordance with Boeing Alert 
Service Bulletin 747-78A2130, dated May 26, 1994, or Boeing Service 
Bulletin 747-78A2166, Revision 1, dated October 9, 1997, as 
applicable.
    (1) The incorporation by reference of Boeing Service Bulletin 
747-78A2166, Revision 1, dated October 9, 1997, is approved by the 
Director of the Federal Register in accordance with 5 U.S.C. 552(a) 
and 1 CFR part 51.
    (2) The incorporation by reference of Boeing Alert Service 
Bulletin 747-78A2130, dated May 26, 1994, was approved previously by 
the Director of the Federal Register as of April 13, 1995 (60 FR 
13623, March 14, 1995).
    (3) 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.
    (i) This amendment becomes effective on August 25, 1999.

    Issued in Renton, Washington, on July 12, 1999.
D. L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-18198 Filed 7-20-99; 8:45 am]
BILLING CODE 4910-13-P