[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]
BILLING CODE 4910-13-V
