[Federal Register Volume 59, Number 215 (Tuesday, November 8, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-27597]


[[Page Unknown]]

[Federal Register: November 8, 1994]


                                                   VOL. 59, NO. 215

                                          Tuesday, November 8, 1994

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-147-AD]

 

Airworthiness Directives; Boeing Model 747-200 and -300 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 747-200 and -
300 series airplanes. This proposal would require various inspections 
and functional tests of the thrust reverser control and indication 
system, and correction of any discrepancy found. This proposal is 
prompted by an investigation to determine the controllability of Model 
747 series airplanes following an in-flight thrust reverser deployment, 
which has revealed that, in the event of thrust reverser deployment 
during high-speed climb or during cruise, these airplanes could 
experience control problems. 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 in the 
thrust reverser control system that can result in inadvertent 
deployment of a thrust reverser during flight.

DATES: Comments must be received by December 9, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-147-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: G. Michael Collins, Aerospace 
Engineer, Propulsion Branch, ANM-140S, FAA, Transport Airplane 
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, 
SW., Renton, Washington 98055-4056; telephone (206) 227-2689; fax (206) 
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 94-NM-147-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-103, Attention: Rules 
Docket No. 94-NM-147-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    In May 1991, a Boeing Model 767 series airplane was involved in an 
accident in which a thrust reverser deployed inadvertently during 
flight. While the investigation of the accident has not revealed the 
cause of that deployment, it has identified a number of possible 
failure modes in the thrust reverser control system. Inadvertent 
deployment of a thrust reverser during flight could result in reduced 
controllability of the airplane.
    The FAA and the aviation industry are conducting an in-depth 
investigation of the thrust reverser systems installed on various types 
of large transport airplanes. In particular, this investigation has 
focused on airplane controllability in the event of an in-flight 
deployment of a thrust reverser, and thrust reverser reliability in 
general. Based on the data gathered from this ongoing investigation, 
the FAA issued several airworthiness directives (AD) to require 
periodic inspections and tests of the thrust reverser systems on 
certain Boeing Model 757 and 767 series airplanes [for example, 
reference AD 91-20-09, amendment 39-8043 (56 FR 46725, September 16, 
1991) for certain Model 757 series airplanes; and AD 92-24-03, 
amendment 39-8408 (57 FR 53258, November 9, 1992) for certain Model 767 
series airplanes]. In addition, the FAA has issued or proposed several 
AD's to require an additional locking device on thrust reversers that 
are installed on Model 737-300/-400/-500, 757, and 767 series airplanes 
[for example, reference AD 94-14-02, amendment 39-8954 (59 FR 33646, 
June 30, 1994) for certain Model 757 series airplanes; and AD 94-16-03, 
amendment 39-8993 (59 FR 41229, August 11, 1994) for certain Model 767 
series airplanes]. These actions were taken to enhance the level of 
reliability on airplane models that were determined to have 
unacceptable flight characteristics following an in-flight deployment 
of a thrust reverser.
    Until now, the investigation of thrust reverser system reliability 
on Boeing Model 747 series airplanes has not been given as high a 
priority as the other Boeing models because Model 747 series airplanes 
have never experienced control problems as a result of an in-flight 
thrust reverser deployment. Based on this long safety record and the 
available evidence up to this time, it has been accepted generally that 
all Model 747 series airplanes would be shown to be controllable 
throughout the flight envelope following an in-flight thrust reverser 
deployment.
    Boeing has responded to an FAA request for further investigation to 
determine the controllability of Model 747 series airplanes following 
an in-flight thrust reverser deployment. The investigation results 
indicate that Model 747-100, -200, -300, -400, SP, and SR series 
airplanes could experience certain control problems in the event of a 
thrust reverser deployment occurring during high-speed climb or during 
cruise.
    In light of that information, the FAA determined that certain 
inspections and functional tests of the thrust reverser control and 
indication system on all Model 747 series airplanes, similar to those 
required previously for Model 757 and 767 series airplanes, are 
necessary as precautionary actions to provide an acceptable level of 
safety for Model 747 series airplanes. Subsequently, on July 13, 1994, 
the FAA issued AD 94-15-05, amendment 39-8976 (59 FR 37655, July 25, 
1994), to require inspections and functional tests of the thrust 
reverser control and indication system on all Model 747-400 series 
airplanes.
    In the preamble to the notice of AD 94-15-05, the FAA indicated 
that it was considering similar rulemaking action for Model 747-200 and 
-300 series airplanes. The FAA now has determined that such rulemaking 
action is indeed necessary, and this proposed AD follows from that 
determination. The FAA has determined that inspections and functional 
tests of the thrust reverser control and indication system, similar to 
those currently required by AD 94-15-05 for Model 747-400 series 
airplanes, are necessary for Model 747-200 and -300 series airplanes in 
order to reduce the exposure of these airplanes to potential undetected 
single failures in the thrust reverser control system. The presence of 
an undetected failure in the thrust reverser control system, in some 
cases, can increase the likelihood of an uncommanded thrust reverser 
deployment in the event of an additional thrust reverser control system 
failure.
    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-78A2130, dated May 26, 1994, which describes procedures for various 
inspections and functional tests of the thrust reverser control and 
indication system, and correction of any discrepancy found. The alert 
service bulletin recommends that these initial inspections and tests be 
accomplished no later than 1,500 flight hours or four months after 
release of the service bulletin. The alert service bulletin also 
recommends a repetitive interval of 1,300 flight hours for tests of the 
center drive unit (CDU) and inspections of the bullnose seal on each 
thrust reverser, and a repetitive interval of 18 months for other 
inspections and tests of the thrust reverser control and indication 
system.
    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 various inspections and functional tests of 
the thrust reverser control and indication system on certain Model 747-
200 and -300 series airplanes, and would require the correction of any 
discrepancy found during the inspections and tests. The actions would 
be required to be accomplished in accordance with the alert service 
bulletin described previously.
    This proposed AD also would require that operators submit a report 
of initial inspection and test results to the FAA.
    In developing appropriate compliance times for the initial 
inspections and tests contained in this proposed AD, the FAA considered 
the safety implications and normal maintenance schedules for timely 
accomplishment of the proposed actions. In consideration of these 
items, the FAA determined that 90 days (for the initial test of the CDU 
and inspection of the bullnose seal on each thrust reverser) and 9 
months (for the initial inspections and tests of the thrust reverser 
control and indication system) represent the maximum intervals of time 
allowable wherein those actions can reasonably be accomplished and an 
acceptable level of safety can be maintained. Further, the FAA has 
determined that the proposed repetitive intervals of 1,000 flight hours 
and 18 months, respectively, are appropriate, based on the service 
history of similar components and on an analysis of the system design 
to predict the reliability of the system during the service life of the 
aircraft.
    The compliance times proposed in this AD correspond to those 
specified in AD 94-15-05 for Model 747-400 series airplanes. The thrust 
reverser control and indication system on Model 747-400 series 
airplanes is similar to the system installed on the airplanes addressed 
in this proposed AD.
    This notice addresses only Model 747-200 and -300 series airplanes 
equipped with General Electric CF6-80C2 series engines with Power 
Management Control (PMC) engine controls. The FAA may consider 
additional rulemaking action for other Model 747-200 and -300 series 
airplanes and Model 747-100, SP, and SR series airplanes as service 
information becomes available for accomplishment of inspections and 
functional tests of the thrust reverser control and indication systems 
on those airplanes.
    There are approximately 9 Model 747-200 and -300 series airplanes 
of the affected design in the worldwide fleet. The FAA estimates that 2 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 33 work hours per airplane to accomplish 
the proposed actions, and that the average labor rate is $55 per work 
hour. Based on these figures, the total cost impact of the proposed AD 
on U.S. operators is estimated to be $3,630, or $1,815 per airplane.
    The total cost impact figure discussed above is 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.
    The regulations proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: Docket 94-NM-147-AD.

    Applicability: Model 747-200 and -300 series airplanes equipped 
with General Electric CF6-80C2 series engines with Power Management 
Control (PMC) engine controls, certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To ensure the integrity of the fail safe features of the thrust 
reverser system, accomplish the following:
    (a) Within 90 days after the effective date of this AD, 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 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.
    (b) Within 9 months after the effective date of this AD, 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 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 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
    (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.
    (d) Within 10 days after performing each initial inspection and 
test required by this AD, submit a report of the inspection and/or 
test results, both positive and negative, to the FAA, Seattle 
Aircraft Certification Office (ACO), ANM-100S, 1601 Lind Avenue, 
SW., Renton, Washington 98055-4056; fax (206) 227-1181. Information 
collection requirements contained in this regulation have been 
approved by the Office of Management and Budget (OMB) under the 
provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et 
seq.) and have been assigned OMB Control Number 2120-0056.
    (e) 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: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (f) 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.

    Issued in Renton, Washington, on November 2, 1994.
S. R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-27597 Filed 11-7-94; 8:45 am]
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