[Federal Register Volume 65, Number 52 (Thursday, March 16, 2000)]
[Proposed Rules]
[Pages 14216-14218]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-6492]


 ========================================================================
 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 65, No. 52 / Thursday, March 16, 2000 / 
Proposed Rules  

[[Page 14216]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-24-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 and 767 Series 
Airplanes Equipped with General Electric CF6-80C2 Series Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 747 and 767 
series airplanes. This proposal would require repetitive functional 
tests of the directional pilot valve (DPV) of the thrust reversers to 
detect pneumatic leakage, and corrective action, if necessary. This 
proposal is prompted by a report of a latent failure mode of the fail-
safe features of the thrust reverser system identified as possible 
leakage of the DPV that is due to a poppet being jammed slightly open 
or a leaking o-ring. The actions specified by the proposed AD are 
intended to ensure the integrity of the fail-safe features of the 
thrust reverser system by preventing possible failure modes, which 
could result in inadvertent deployment of a thrust reverser during 
flight, and consequent reduced controllability of the airplane.

DATES: Comments must be received by May 1, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-24-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    Comments may be inspected at this location between 9:00 a.m. and 
3:00 p.m., Monday through Friday, except Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

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:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-24-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 2000-NM-24-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA received a report from the manufacturer indicating a new 
latent failure mode of the fail-safe features of the thrust reverser 
system. This failure mode was identified as possible leakage of the 
directional pilot valve (DPV) of the thrust reversers due to a poppet 
being jammed slightly open or a leaking o-ring. Such undetected leakage 
past the DPV could result in sufficient pnuematic pressure developing 
downstream of the DPV at takeoff thrust to actuate the directional 
control valve to the deploy position. This failure mode, in combination 
with another thrust reverser failure condition or component failure, 
could result in the following:
     Significant degradation of the features intended to ensure 
that the thrust reverser remains stowed during all anticipated 
operating conditions for airplanes that have incorporated the thrust 
reverser actuation system brake. Or
     A potential in-flight thrust reverser deployment for 
airplanes that have not incorporated the thrust reverser actuation 
system brake.
    Such conditions, if not corrected, could result in inadvertent 
deployment of a thrust reverser during flight, and consequent reduced 
controllability of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-78A2170, and Boeing Service Bulletin 767-78-0084, both dated 
October 21, 1999, which describe procedures for repetitive functional 
tests of the DPV of the thrust reversers to detect pneumatic leakage, 
and correction of any discrepancies. Accomplishment of the actions 
specified in the service bulletins is intended to adequately address 
the identified unsafe condition.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require repetitive functional tests of the DPV of the 
thrust reversers to detect pneumatic leakage, and corrective

[[Page 14217]]

action, if necessary. The actions are required to be accomplished in 
accordance with the service bulletins described previously, except as 
discussed below.
    Correction of any discrepancy detected is required to be 
accomplished in accordance with the procedures described in the 
applicable Boeing 747 or 767 Airplane Maintenance Manual.

Cost Impact

    There are approximately 331 Model 767 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 108 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 10 work hours (5 work hours per engine) per 
airplane to accomplish the proposed functional test, and that the 
average labor rate is $60 per work hour. Based on these figures, the 
cost impact of the functional test proposed by this AD on U.S. 
operators is estimated to be $64,800, or $600 per airplane, per test 
cycle.
    None of the Model 747 series airplanes affected by this action are 
on the U.S. Register. All Model 747 series airplanes included in the 
applicability of this rule currently are operated by non-U.S. operators 
under foreign registry; therefore, they are not directly affected by 
this AD action. However, the FAA considers that this rule is necessary 
to ensure that the unsafe condition is addressed in the event that any 
of these subject airplanes are imported and placed on the U.S. Register 
in the future.
    Should an affected Model 747 series airplane be imported and placed 
on the U.S. Register in the future, it would require approximately 20 
work hours (5 work hours per engine) to accomplish the proposed 
functional test, at an average labor rate of $60 per work hour. Based 
on these figures, the cost impact of the functional test proposed by 
this AD would be approximately $1,200 per airplane, per test cycle.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the proposed 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 proposed herein would 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 proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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:

Boeing: Docket 2000-NM-24-AD.

    Applicability: Model 747 and 767 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) 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, which could 
result in inadvertent deployment of a thrust reverser during flight, 
and consequent reduced controllability of the airplane, accomplish 
the following:
    (a) For Model 747 and 767 series airplanes equipped with thrust 
reversers that HAVE NOT been modified in accordance with Boeing 
Service Bulletin 747-78-2151 or 767-78-0063, as applicable, or a 
production equivalent: Within 60 days after the effective date of 
this AD, perform a functional test of the directional pilot valve 
(DPV) of the thrust reversers to detect pneumatic leakage in 
accordance with Boeing Alert Service Bulletin 747-78A2170, or Boeing 
Service Bulletin 767-78-0084, as applicable, both dated October 21, 
1999. Repeat the functional test thereafter at intervals not to 
exceed 1,000 flight hours.
    (b) For Model 747 and 767 series airplanes equipped with thrust 
reversers that have been modified in accordance with Boeing Service 
Bulletin 747-78-2151 or 767-78-0063, as applicable, or a production 
equivalent: Within 180 days after the effective date of this AD, 
perform a functional test of the DPV of the thrust reversers to 
detect pneumatic leakage in accordance with Boeing Alert Service 
Bulletin 747-78A2170, or Boeing Service Bulletin 767-78-0084, as 
applicable, both dated October 21, 1999. Repeat the functional test 
thereafter at intervals not to exceed 5,000 flight hours.
    (c) If any functional test required by paragraph (a) or (b) of 
this AD cannot be successfully performed as specified in Boeing 
Alert Service Bulletin 747-78A2170, or Boeing Service Bulletin 767-
78-0084, as applicable, both dated October 21, 1999; or if any 
discrepancy is detected during any functional test required by 
paragraph (a) or (b) of this AD: Prior to further flight, correct 
the discrepancy in accordance with the procedures specified in the 
applicable Boeing Model 747 or 767 Airplane Maintenance Manual. 
Additionally, prior to further flight, any failed functional test 
required by paragraph (a) or (b) of this AD must be repeated and 
successfully accomplished. Repeat the functional test thereafter at 
the intervals required by paragraph (a) or (b) of this AD, as 
applicable.

Alternative Methods of Compliance

    (d) 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.

Special Flight Permit

    (e) 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.


[[Page 14218]]


    Issued in Renton, Washington, on March 10, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-6492 Filed 3-15-00; 8:45 am]
BILLING CODE 4910-13-U