[Federal Register Volume 59, Number 154 (Thursday, August 11, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-18840]
[[Page Unknown]]
[Federal Register: August 11, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 93-NM-178-AD; Amendment 39-8993; AD 94-16-03]
Airworthiness Directives; Boeing Model 767 Series Airplanes
Equipped with Pratt & Whitney JT9D-7R4 or General Electric CF6-80A
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 767 series airplanes, that
currently requires inspections, adjustments, and functional tests of
the thrust reverser system. This amendment adds a requirement for
installation of an additional thrust reverser system locking feature,
periodic functional tests of that locking feature following its
installation, and repair of any discrepancy found. This amendment is
prompted by the identification of a modification that ensures that the
level of safety inherent in the original type design of the thrust
reverser system is further enhanced. The actions specified by this AD
are intended to prevent possible discrepancies in the thrust reverser
control system that can result in inadvertent deployment of a thrust
reverser during flight.
DATES: Effective September 12, 1994.
The incorporation by reference of Boeing Service Bulletin 767-78-
0060, Revision 2, dated August 19, 1993, and Boeing Service Bulletin
767-78-0061, Revision 1, dated August 5, 1993, as listed in the
regulations, is approved by the Director of the Federal Register as of
September 12, 1994.
The incorporation by reference of Boeing Service Bulletin 767-78-
0054, dated December 13, 1991, and Boeing Service Bulletin 767-78-0053,
dated December 13, 1991, as listed in the regulations, was approved
previously by the Director of the Federal Register as of January 27,
1992 (57 FR 3004, January 27, 1992).
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: Richard Simonson, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate,
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (206) 227-2683; fax (206) 227-1181.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) by superseding AD 92-03-03,
amendment 39-8157 (57 FR 3004, January 27, 1992), which is applicable
to certain Boeing Model 767 series airplanes, was published in the
Federal Register on February 2, 1994 (59 FR 4870). The action proposed
to require inspections, adjustments, and functional tests of the thrust
reverser system; installation of an additional thrust reverser system
locking feature; periodic functional tests of that locking feature
following its installation; and repair of any discrepancy found.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter supports the proposed rule.
The Air Transport Association (ATA) of America, on behalf of its
members, requests that a note or provision be added to the proposal to
indicate that relief provided by the Master Minimum Equipment List
(MMEL) is not revoked by the adoption of this AD. The commenter states
that deactivation of a thrust reverser is not considered to be an
unsafe procedure and is, therefore, not the subject of the proposed
rule.
The FAA concurs. The FAA agrees that certain relief may be provided
to operators as requested by the commenter, and finds that the airplane
may be operated in accordance with the provisions and limitations
specified in the FAA-approved MMEL, provided that no more than one
thrust reverser on an airplane is inoperative and that no synch-lock on
that airplane is in an unlocked position. The FAA has revised paragraph
(e) of the final rule accordingly.
The ATA also questions the requirement contained in paragraph (e)
of the proposal for repetitive functional tests of the synch-lock
installation. The ATA states that its members are not opposed to
accomplishing the proposed tests as part of their maintenance programs,
but are opposed to accomplishing the tests as part of the requirements
of an AD. The ATA reasons that the ``intent'' of the proposed rule is
to terminate the tests required by AD 92-03-03.
The ATA questions the rationale for the proposed repetitive
functional tests of the synch-lock installation, since the synch-lock
configuration has not been shown to be unsafe. The ATA acknowledges the
FAA's statement in the Discussion section of the proposal that the
synch-lock is a new design whose reliability has not been adequately
proven through service experience. The ATA states that, under this
rationale, an operator's maintenance program for newly certificated
airplanes would simply consist of Certification Maintenance Requirement
(CMR) items, since the reliability of newly designed systems has not
been adequately proven through service experience. The ATA believes
that AD control of the proposed repetitive tests is justified only if
it can be shown that the tests cannot be administered safely within an
operator's maintenance program.
The ATA acknowledges that without issuance of an AD, the proposed
repetitive tests may not be incorporated into every operator's
maintenance program in a common manner at common intervals. In light of
this consideration, the ATA requests that an alternative to
accomplishment of the repetitive tests be provided in the final rule.
The suggested alternative for paragraph (e) of the AD follows: Within 3
months after accomplishing the synch-lock installation, revise the FAA-
approved maintenance inspection program to include a functional test of
the synch-lock. The initial test would be accomplished within 1,500
hours time-in-service after modification. The AD would no longer be
applicable to operators that have acceptably revised their maintenance
programs. Operators choosing this alternative could use an alternative
recordkeeping method in lieu of that required by section 91.417 or
section 121.380 of the Federal Aviation Regulation (14 CFR 91.417 or
121.380). The FAA would be defined as the cognizant Principal
Maintenance Inspector (PMI) for operators electing this alternative.
The ATA believes that its proposal should be adopted because the
proposed repetitive tests will likely continue for as long as Model 767
series airplanes are operated. The ATA adds that, while there are
numerous AD's that require repetitive inspections that would continue
for the life of the aircraft, in such cases, either a satisfactory
terminating action has not been developed or service experience has
shown that control of the inspections cannot be safely administered
through an operator's maintenance program. The ATA's proposal is
intended to minimize the impact of the AD process on an operator's
maintenance program.
The FAA recognizes the concerns of the commenter regarding the
requirement for periodic functional tests of the synch-lock following
its installation, as required by paragraph (e) of this AD. However, the
FAA has determined that such tests are necessary in order to provide an
adequate level of safety and to ensure the integrity of the synch-lock
installation. The actions required by this AD are consistent with
actions that have been identified by an industry-wide task force as
necessary to ensure adequate safety of certain thrust reverser systems
installed on transport category airplanes. Representatives of the
Aerospace Industries Association (AIA) of America, Inc., and the FAA
comprise that task force. Representatives from other organizations,
such as the ATA, have participated in various discussions and work
activities resulting from the recommendations of the task force.
The FAA acknowledges that the functional tests specified in
paragraph (e) of this AD and CMR items are similar in terms of
scheduled maintenance and recordkeeping. However, this AD addresses an
unsafe condition and requires installation of the synch-lock to correct
that unsafe condition. The FAA has determined that the requirement for
functional tests is necessary in order to ensure the effectiveness of
that installation in addressing that unsafe condition. As discussed in
the preamble of the proposal, this determination is based on the fact
that the synch-lock is a new design whose reliability has not been
adequately proven through service experience. In addition, service
experience to date has demonstrated that failures can occur within the
synch-lock that may not be evident during normal operation of the
thrust reverser system and may not result in activation of the synch-
lock ``unlock'' indicator. The FAA notes that the ATA's suggested
alternative to accomplishment of the functional tests would permit each
operator to determine whether and how often these tests should be
conducted. In light of the severity of the unsafe condition, however,
the FAA has determined that allowing this degree of operator discretion
is not appropriate at this time. Therefore, this AD is necessary to
ensure that operators accomplish tests of the integrity of the synch-
lock installation in a common manner and at common intervals.
The ATA also requests that the proposed interval of 1,000 hours
time-in-service for accomplishment of the repetitive functional tests
specified in paragraph (e) of the proposal be extended to 1,500 hours
time-in-service. The ATA explains that Boeing has recommended an
interval of 4,000 hours time-in-service for inclusion in the next
Maintenance Review Board (MRB) report. If the FAA denies an extension
of the proposed interval, the ATA requests that the FAA explain why its
analysis is so stringent in comparison with Boeing's recommendation.
The ATA believes that AD compliance times should be consistent with
operators' regularly scheduled maintenance unless a risk analysis
requires otherwise. The ATA reasons that compliance times that are
inconsistent with scheduled maintenance holds force operators to
reschedule maintenance actions at considerable expense and disruption
to their operations.
The FAA has reconsidered the proposed interval of 1,000 hours time-
in-service for accomplishment of the initial and repetitive functional
tests required by paragraph (e) of this AD. The FAA recognizes that an
initial and repetitive interval of 4,000 hours time-in-service for
accomplishment of these functional tests, as recommended by Boeing,
corresponds more closely to the interval at which most of the affected
operators conduct regularly scheduled ``C'' checks. In light of the
safety implications of the addressed unsafe condition and the practical
aspects of accomplishing orderly functional tests of the fleet during
regularly scheduled maintenance where special equipment and trained
maintenance personnel will be readily available, the FAA finds that
accomplishment of the tests at intervals of 4,000 hours time-in-service
will provide an acceptable level of safety. Paragraph (e) of the final
rule has been revised accordingly.
The ATA also requests that the cost of parts be included in the
economic impact information, below, in order to present a total cost
impact of the rule on the ``U.S. public.'' The ATA recognizes that
Boeing plans to supply parts at no cost to operators; however, the ATA
suspects the parts costs borne by Boeing would be substantial. The FAA
does not concur with the commenter's request. The total cost impact
figures shown in the economic impact information, below, represent the
costs for time necessary to perform the inspections, adjustments,
tests, and modification required by this AD. The cost analysis in AD
rulemaking actions typically does not include parts costs when those
parts are provided by the manufacturer at no cost to operators. Such
costs are not attributable to the AD; the manufacturer would incur
these costs even if no AD were issued.
The FAA has revised paragraph (d) of the final rule to specify that
the correct reference for Boeing Service Bulletin 767-78-0061 is
Revision 1, rather than Revision 2, as cited in the proposal. The issue
date of Revision 1 (August 5, 1993) appeared correctly in the proposed
rule.
The FAA also has revised paragraphs (a) and (b) of the final rule
to clarify the appropriate compliance time. Those paragraphs restate
requirements for accomplishment of certain actions required by AD 92-
03-03. The FAA's intent is that the tests, inspections, and adjustments
required by those paragraphs would have been accomplished within 60
days after January 27, 1992 (the effective date of AD 92-03-03).
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.
There are approximately 119 Model 767 series airplanes equipped
with General Electric CF6-80A series engines of the affected design in
the worldwide fleet. The FAA estimates that 69 airplanes of U.S.
registry will be affected by this AD. The inspections, adjustments, and
functional tests required currently by AD 92-03-03 require
approximately 16 work hours per airplane to accomplish the required
actions, at an average labor rate of $55 per work hour. Based on these
figures, the total cost impact of those actions on U.S. operators of
Model 767 series airplanes equipped with General Electric CF6-80A
series engines is estimated to be $60,720, or $880 per airplane.
For U.S. operators of Model 767 series airplanes equipped with
General Electric CF6-80A series engines, the FAA estimates that it will
take approximately 786 work hours per airplane to accomplish the
modification required by this AD, and 1 work hour to accomplish the
required functional tests, at an average labor rate of $55 per work
hour. Required parts will be supplied by the manufacturer at no cost to
operators. Based on these figures, the total cost impact of those
actions on U.S. operators of Model 767 series airplanes equipped with
General Electric CF6-80A series engines is estimated to be $2,986,665,
or $43,285 per airplane.
There are approximately 95 Model 767 series airplanes equipped with
Pratt & Whitney JT9D-7R4 series engines of the affected design in the
worldwide fleet. The FAA estimates that 30 airplanes of U.S. registry
will be affected by this AD. The inspections, adjustments, and
functional tests required currently by AD 92-03-03 require
approximately 16 work hours per airplane to accomplish the required
actions, at an average labor rate of $55 per work hour. Based on these
figures, the total cost impact of those actions on U.S. operators of
Model 767 series airplanes equipped with Pratt & Whitney JT9D-7R4
series engines is estimated to be $26,400, or $880 per airplane.
For U.S. operators of Model 767 series airplanes equipped with
Pratt & Whitney JT9D-7R4 series engines, the FAA estimates that it will
take approximately 812 work hours per airplane to accomplish the
modification required by this AD, and 1 work hour to accomplish the
required functional tests, at an average labor rate of $55 per work
hour. Required parts will be supplied by the manufacturer at no cost to
operators. Based on these figures, the total cost impact of those
actions on U.S. operators of Model 767 series airplanes equipped with
Pratt & Whitney JT9D-7R4 series engines is estimated to be $1,341,450,
or $44,715 per airplane.
The total 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.
The number of required work hours for accomplishing the required
functional tests, as indicated above, is presented as if the
accomplishment of those tests required by this AD were to be conducted
as ``stand alone'' actions. However, in actual practice, those tests
for the most part will be accomplished coincidentally or in combination
with normally scheduled airplane inspections and other maintenance
program tasks. Therefore, the actual number of necessary additional
work hours for accomplishment of the functional tests will be minimal
in many instances. Additionally, any costs associated with special
airplane scheduling will be minimal.
The FAA recognizes that the required modification will require a
large number of work hours to accomplish. However, the 5-year
compliance time specified in paragraph (d) of this AD should allow
ample time for the synch-lock installation to be accomplished
coincidentally with scheduled major airplane inspection and maintenance
activities, thereby minimizing the costs associated with special
airplane scheduling.
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. 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 removing amendment 39-8157 (57 FR
3004, January 27, 1992), and by adding a new airworthiness directive
(AD), amendment 39-8993, to read as follows:
94-16-03 Boeing: Amendment 39-8993. Docket 93-NM-178-AD. Supersedes
AD 92-03-03, Amendment 39-8157.
Applicability: Model 767 series airplanes equipped with Pratt &
Whitney JT9D-7R4 or General Electric CF6-80A series engines,
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:
Restatement of Actions Required by AD 92-03-03
(a) For airplanes equipped with Pratt & Whitney JT9D-7R4 series
engines: Within 60 days after January 27, 1992 (the effective date
of AD 92-03-03, amendment 39-8157), and thereafter at intervals not
to exceed 3,000 flight hours, perform the tests, inspections, and
adjustments described in Boeing Service Bulletin 767-78-0054, dated
December 13, 1991.
(1) Following any maintenance action that could affect the
thrust reverser system: Repeat the tests, inspections, and
adjustments required by paragraph (a) of this AD on the affected
engine, prior to further flight, in accordance with the service
bulletin.
(2) Thereafter, following any maintenance action, continue to
perform the repetitive tests, inspections, and adjustments required
by paragraph (a) of this AD on the affected engine at intervals not
to exceed 3,000 flight hours.
(b) For airplanes equipped with General Electric CF6-80A series
engines: Within 60 days after January 27, 1992 (the effective date
of AD 92-03-03, amendment 39-8157), and thereafter at intervals not
to exceed 3,000 flight hours, perform the tests, inspections, and
adjustments described in Boeing Service Bulletin 767-78-0053, dated
December 13, 1991.
(1) Following any maintenance action that could affect the
thrust reverser system, repeat the tests, inspections, and
adjustments required by paragraph (b) of this AD on the affected
engine, prior to further flight, in accordance with the service
bulletin.
(2) Thereafter, following any maintenance action, continue to
perform the repetitive tests, inspections, and adjustments required
by paragraph (b) of this AD on the affected engine at intervals not
to exceed 3,000 flight hours.
(c) If any test, inspection, and/or adjustment required by
paragraph (a) or (b) of this AD cannot be successfully performed, or
if any test, inspection, and/or adjustment results in findings that
are unacceptable in accordance with Boeing Service Bulletin 767-78-
0054, dated December 13, 1991, or Boeing Service Bulletin 767-78-
0053, dated December 13, 1991, as applicable, accomplish paragraphs
(c)(1) and (c)(2) of this AD.
(1) Prior to further flight, deactivate the associated thrust
reverser in accordance with Section 78-31-1 of Boeing Document
D630T002, ``Boeing 767 Dispatch Deviation Guide,'' Revision 9, dated
May 1, 1991. No more than one thrust reverser on any airplane may be
deactivated under the provisions of this paragraph.
(2) Within 10 days after deactivation of any thrust reverser in
accordance with this paragraph, the thrust reverser must be repaired
in accordance with Boeing Service Bulletin 767-78-0054, dated
December 13, 1991, or Boeing Service Bulletin 767-78-0053, dated
December 13, 1991, as applicable; the tests and/or inspections
required by paragraph (a) or (b) of this AD must be successfully
accomplished; and the thrust reverser must then be reactivated.
New Actions Required By This AD:
(d) Within 5 years after the effective date of this AD, install
an additional thrust reverser system locking feature (synch-lock
installation) in accordance with Boeing Service Bulletin 767-78-
0060, Revision 2, dated August 19, 1993 (for Model 767 series
airplanes equipped with General Electric CF6-80A series engines), or
Boeing Service Bulletin 767-78-0061, Revision 1, dated August 5,
1993 (for Model 767 series airplanes equipped with Pratt & Whitney
JT9D-7R4 series engines), as applicable. Installation of the
additional thrust reverser system locking feature, as required by
this paragraph, constitutes terminating action for the requirements
of paragraphs (a) through (c) of this AD.
(e) Within 4,000 hours time-in-service after installing the
synch-lock required by paragraph (d) of this AD (either in
production or by retrofit), or within 4,000 hours time-in-service
after the effective date of this AD, whichever occurs later; and
thereafter at intervals not to exceed 4,000 hours time-in-service:
Perform functional tests of the synch-lock in accordance with the
``Thrust Reverser Synch-Lock Test'' procedures specified below. If
any discrepancy is found during any test, prior to further flight,
correct it in accordance with procedures described in the Boeing 767
Maintenance Manual. The airplane may be operated in accordance with
the provisions and limitations specified in the FAA-approved Master
Minimum Equipment List (MMEL), provided that no more than one thrust
reverser on an airplane is inoperative and that no synch-lock on
that airplane is in an unlocked position.
Thrust Reverser Synch-Lock Test
1. General
A. There are two thrust reverser synch-locks on each engine. The
thrust reverser synch-locks are installed on the lower non-locking
hydraulic actuator of each thrust reverser sleeve.
B. This task has two parts that must be accomplished:
(1) The first part does a test of the electrical circuit which
controls the operation of each thrust reverser synch-lock.
(2) The second part does a test of the mechanical condition of
each thrust reverser synch-lock.
C. The thrust reverser synch-lock is referred to as the ``synch-
lock'' in this procedure.
2. Thrust Reverser Synch-Lock Integrity Test
A. Equipment
(1) Multi-meter, Simpson 260 or equivalent--commercially
available.
B. Prepare to do the integrity test for the synch-locks.
(1) Supply electrical power.
(2) For the left engine, make sure these circuit breakers on the
overhead circuit breaker panel, P11, are closed:
(a) L ENG T/R CONT
(b) L ENG T/R IND
(c) L ENG T/R SSL CONT
(3) For the right engine, make sure these circuit breakers on
the overhead circuit breaker panel, P11, are closed:
(a) R ENG T/R CONT
(b) R ENG T/R IND
(c) R ENG T/R SSL CONT
(d) AIRPLANES WITH HYDRAULIC MOTOR-DRIVEN GENERATORS (ETOPS): R
ENG T/R CONT ALTN
(e) AIRPLANES WITH HYDRAULIC MOTOR-DRIVEN GENERATORS (ETOPS): R
ENG T/R IND ALTN
(4) Open the fan cowl panels.
C. Do the electrical test for the synch-locks.
(1) Do these steps to make sure there are no ``hot'' short
circuits in the electrical system which can accidentally supply
power to the synch-locks:
(a) Remove the applicable L(R) electrical connectors,
D20194(D20196), from the L(R) synch-locks, V170(V171).
Note: You can find the synch-locks attached to the lower non-
locking hydraulic actuators on the applicable thrust reverser
sleeves.
(b) Use a multi-meter on the plug end of the applicable
electrical connector to make sure that these conditions are correct:
------------------------------------------------------------------------
From equipment To equipment Condition
------------------------------------------------------------------------
D20194 PIN 1............. D20194 PIN 2...... -3 TO +1 VDC and
continuity (less than 5
OHMS).
D20196 PIN 1............. D20196 PIN 2...... -3 TO +1 VDC and
continuity (less than 5
OHMS).
------------------------------------------------------------------------
(c) If you did not find these conditions to be correct, you must
do these steps:
(1) Make a careful visual inspection of all the electrical wires
and connectors between the synch-lock and its applicable power
circuit breaker.
(2) Repair all the unserviceable electrical wire and connectors
that you find.
(3) Use the multi-meter again to make sure there are no ``hot''
short circuits in the electrical system which can accidentally
supply power to the synch-locks.
(d) If you find the correct conditions when you use the multi-
meter, continue on and do the mechanical test of the synch-locks.
Note: Make sure the circuit breakers shown above continue to be
set to the closed position. Do not install the electrical connectors
on the synch-locks at this time.
D. Do the mechanical test for the synch-locks.
(1) Supply hydraulic power.
WARNING: MAKE SURE ALL PERSONS AND EQUIPMENT ARE CLEAR OF THE
AREA BEHIND EACH THRUST REVERSER. IF YOU DO NOT OBEY THIS
INSTRUCTION, INJURIES TO PERSONS OR DAMAGE TO EQUIPMENT CAN OCCUR IF
THE SYNCH-LOCKS DO NOT OPERATE CORRECTLY AND THE THRUST REVERSER
EXTENDS.
(2) Move the reverse thrust levers for the two engines to try to
extend the thrust reversers with hydraulic power.
Note: If the thrust reversers do not extend, the synch-locks are
serviceable. If the thrust reversers extend, the applicable synch-
locks did not operate correctly.
(3) Replace the applicable synch-locks on the thrust reverser
that extended when you moved the reverse thrust levers.
(4) Make sure the reverse thrust levers are in the fully stowed
position.
(5) Install the applicable L(R) electrical connectors,
D20194(D20196), on the L(R) synch-locks, V170(V171).
WARNING: MAKE SURE ALL PERSONS AND EQUIPMENT ARE CLEAR OF THE
AREA BEHIND THE THRUST REVERSERS. IF YOU DO NOT OBEY THIS
INSTRUCTION, INJURIES TO PERSONS OR DAMAGE TO EQUIPMENT CAN OCCUR
WHEN THE THRUST REVERSERS ARE EXTENDED.
(6) Move the reverser thrust levers for the two engines to
extend the thrust reversers with hydraulic power.
Note: If the thrust reversers extend, the synch-locks are
serviceable. If the thrust reversers do not extend, the applicable
synch-locks did not operate correctly.
(7) Replace the applicable synch-locks on the thrust reverser
that did not extend when you moved the reverse thrust levers.
E. Put the airplane back to its usual condition.
(1) Move the reverse thrust levers to fully retract the thrust
reversers on the two engines with hydraulic power.
(2) Remove the hydraulic power if it is not necessary.
(3) Remove the electrical power if it is not necessary.
(4) Close the fan cowl panels.
(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 (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.
(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.
(h) The installation shall be done in accordance with Boeing
Service Bulletin 767-78-0060, Revision 2, dated August 19, 1993; and
Boeing Service Bulletin 767-78-0061, Revision 1, dated August 5,
1993; as applicable. 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. Certain other actions shall be done in
accordance with Boeing Service Bulletin 767-78-0054, dated December
13, 1991; and Boeing Service Bulletin 767-78-0053, dated December
13, 1991; as applicable. The incorporation by reference of these
documents was approved previously by the Director of the Federal
Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of
January 27, 1992 (57 FR 3004, January 27, 1992). 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 September 12, 1994.
Issued in Renton, Washington, on July 28, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-18840 Filed 8-10-94; 8:45 am]
BILLING CODE 4910-13-U
