AD 2000-17-06

[Federal Register Volume 65, Number 170 (Thursday, August 31, 2000)]
[Rules and Regulations]
[Pages 52905-52907]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 00-21717]



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Federal Register / Vol. 65, No. 170 / Thursday, August 31, 2000 / 
Rules and Regulations

[[Page 52905]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-24-AD; Amendment 39-11880; AD 2000-17-06]
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: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 747 and 767 series airplanes, that 
requires repetitive functional tests of the directional pilot valve 
(DPV) of the thrust reversers to detect pneumatic leakage, and 
corrective action, if necessary. This amendment 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 this 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: Effective October 5, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 5, 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: Dennis Kammers, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 227-2793; 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 and 767 
series airplanes series airplanes was published in the Federal Register 
on March 16, 2000 (65 FR 14216). That action proposed to require 
repetitive functional tests of the directional pilot valve (DPV) of the 
thrust reversers to detect pneumatic leakage, and corrective action, if 
necessary.

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.

Supportive Comment

    One commenter concurs with the proposed rule and states that it has 
accomplished the initial inspection (functional test) specified in the 
proposal, and has incorporated the 5,000 hour repetitive inspection 
(test) requirements into its existing maintenance program for the 
affected airplanes.

Request Credit for Previous Accomplishment of Functional Test

    One commenter requests that the FAA revise the proposal to provide 
credit for accomplishment of the directional pilot valve (DPV) 
functional test during production. The FAA concurs. The required DPV 
functional test can be accomplished in accordance with either the 
service bulletin or a production equivalent. A note has been added to 
the final rule to clarify that credit is given for previous 
accomplishment of the DPV functional test during production.

Request To Extend Repetitive Test Interval

    One commenter requests that the FAA extend the interval for the 
proposed repetitive functional tests, as specified in paragraph (b) of 
the proposal, from 5,000 flight hours to 6,000 flight hours. The 
commenter states that the 6,000-flight-hour interval coincides with the 
check recommended in the Boeing 767 Maintenance Planning Document, and 
would allow operators to accomplish the functional test during 
scheduled ``C'' checks. The commenter adds that this extension would 
decrease the necessity to schedule additional maintenance time for its 
airplanes in order to meet the 5,000 flight-hour requirement.
    The FAA concurs with the commenter's request. The intent of the AD 
is that the functional tests be conducted during a regularly scheduled 
maintenance visit, for the majority of the affected fleet, while still 
ensuring the thrust reverser system integrity. This would occur when 
the airplanes would be located at a base where special equipment and 
trained personnel would be readily available, if necessary. Based on 
the information supplied by the commenter, the FAA now recognizes that 
an interval of 6,000 flight hours corresponds more closely to most of 
the affected operators' normal maintenance schedules. Paragraph (b) of 
the final rule has been revised to require accomplishment of the 
repetitive tests at intervals not to exceed 6,000 flight hours.

Request To Revise Cost Impact Information

    One commenter notes that the proposed rule incorrectly states, 
``None of the Model 747 series airplanes affected by this action are on 
the U.S. Register.'' The commenter states that this is inaccurate 
because all of its Model 747 series airplanes are affected by the 
proposed rule.
    In light of the information supplied by the commenter, the FAA 
agrees that there are eight Model 747 series airplanes on the U.S. 
Register that are affected by this final rule. Therefore, the cost 
impact information, below, has been revised accordingly.

[[Page 52906]]

Terminating Modification

    One commenter states that the proposed rule appears to be open-
ended in that there is no modification available to correct the 
potential latent failure of the DPV and terminate the DPV inspections/
tests. The commenter requests information on any planned corrective 
modification to the DPV in the future.
    The FAA agrees with the commenter's observation that there is no 
proposed modification to the potential latent failure of the DPV or to 
terminate the repetitive DPV inspections/tests. Since the issuance of 
the proposed rule, the manufacturer has advised the FAA that it is 
developing a modified DPV 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. 
That rulemaking may provide terminating action for the requirements of 
this final rule if a DPV that is not subject to the unsafe condition is 
approved for installation on an airplane equipped with GE CF6-80C2 
series engines.

Request To Revise Paragraph (c)

    One commenter states that paragraph (c) of the proposal should be 
revised to allow use of the 747-400 Dispatch Deviations Procedures 
Guide-specifically, minimum equipment list (MEL) Chapter 78-31-1, which 
enables airplanes to dispatch with a thrust reverser deactivated for up 
to 10 days. The commenter states that this ensures flight safety. The 
FAA does not concur. The MEL is not intended to provide safeguard 
measures for hardware with known, potentially catastrophic, failure 
modes. While this DPV failure mode does not lead directly to a thrust 
reverser deployment, it does lower the overall reliability of the 
thrust reverser system. Therefore, when DPV leakage is identified, this 
AD requires correction of the problem, rather than deferral. No change 
to paragraph (c) of 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 418 Model 747 and 767 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 116 
airplanes of U.S. registry will be affected by this AD.
    For affected Model 747 series airplanes (8 U.S.-registered 
airplanes): It will take approximately 20 work hours (5 work hours per 
engine) to accomplish the required functional test, 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 approximately $9,600, or $1,200 per airplane, per test cycle.
    For affected Model 767 series airplanes (108 U.S.-registered 
airplanes): It will take approximately 10 work hours (5 work hours per 
engine) per airplane to accomplish the required functional test, 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 $64,800, or $600 per airplane, per test 
cycle.
    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:

2000-17-06 Boeing: Amendment 39-11880. 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:

Repetitive Functional Tests

    (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

[[Page 52907]]

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 6,000 flight hours.

    Note 2: For airplanes modified during production: Functional 
tests accomplished in accordance with a production equivalent are 
acceptable for the initial functional test required by paragraph (b) 
of this AD.

Corrective Action

    (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 3: 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 paragraphs (b) and (c) of this AD, the 
functional test shall be done in accordance with Boeing Alert 
Service Bulletin 747-78A2170, dated October 21, 1999; or Boeing 
Service Bulletin 767-78-0084, dated October 21, 1999. 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.
    (g) This amendment becomes effective on October 5, 2000.

    Issued in Renton, Washington, on August 21, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-21717 Filed 8-30-00; 8:45 am]
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