[Federal Register Volume 59, Number 117 (Monday, June 20, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-14755]


[[Page Unknown]]

[Federal Register: June 20, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-NM-111-AD; Amendment 39-8942; AD 94-13-02]

 

Airworthiness Directives; Boeing Model 757 Series Airplanes 
Equipped With Rolls-Royce RB211-535E4/E4B 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 757 series airplanes, that requires 
tests of the thrust reverser system, and repair, if necessary; 
installation of a modification that terminates those tests; and 
repetitive operational checks of that installation, and repair, if 
necessary. This amendment is prompted by results of a safety review, 
which revealed that in-flight deployment of a thrust reverser could 
result in a significant reduction in the controllability of the 
airplane. The actions specified by this AD are intended to prevent 
deployment of a thrust reverser in flight and subsequent reduced 
controllability of the airplane.

DATES: Effective July 20, 1994.

    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 20, 1994.
ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207; and Rolls-Royce plc, P.O. Box 31, Derby DE24 
8BJ, England, ATTN: Technical Publications Department. 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: Jeffrey Duven, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (206) 227-2688; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations to include an airworthiness directive (AD) that is 
applicable to certain Boeing Model 757 series airplanes was published 
in the Federal Register on September 8, 1993 (58 FR 47225). That action 
proposed to require tests of the thrust reverser system, and repair, if 
necessary; installation of a modification that would terminate those 
tests; and repetitive operational checks of that installation, and 
repair, if necessary.
    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.
    Several commenters question the requirement for periodic 
operational checks of the sync-lock following its installation, as 
specified in paragraph (c) of the proposal:
    1. The Air Transport Association (ATA) of America, on behalf of its 
members, states that, while ATA members are not opposed to 
accomplishing the proposed checks as part of their maintenance 
programs, these members are opposed to accomplishing the checks as part 
of the requirements of an AD. The commenters believe that the 
requirement for operational checks is equivalent to issuing a 
Certification Maintenance Requirements (CMR) item by means of an AD.
    ATA adds that, if the FAA finds sufficient justification to include 
the requirement for operational checks in the AD, an alternative to 
accomplishment of the checks should be provided in the final rule. ATA 
reasons that an alternative is justified because no data exist to show 
that repetitive checks of a modified thrust reverser cannot be handled 
adequately through an operator's maintenance program. The suggested 
alternative follows: Within 3 months after accomplishing the sync-lock 
installation, revise the FAA-approved maintenance inspection program to 
include an operational check of the sync-lock. The initial check would 
be accomplished within 1,000 hours time-in-service after modification. 
The AD would no longer be applicable for operators that have acceptably 
revised the maintenance program. Operators choosing this alternative 
could use an alternative recordkeeping method in lieu of that required 
by Federal Aviation Regulation (FAR) 91.417 or 121.380. The FAA would 
be defined as the cognizant Principal Maintenance Inspector (PMI) for 
operators electing this alternative.
    2. One commenter, Boeing, requests that the proposed requirement 
for operational checks be removed from the AD until the FAA reviews the 
``more comprehensive'' scheduled maintenance recommendations developed 
by the Model 757/767 Thrust Reverser Working Group, which will be 
recommended in the next revision to the Maintenance Review Board (MRB) 
report. Boeing believes that adoption of the maintenance 
recommendations contained in that forthcoming revision will ensure that 
an adequate level of safety (with regard to the sync-lock installation) 
will be maintained by all operators of Model 757 series airplanes.
    3. One commenter states that these checks should not be required 
because failures of the sync-lock would not be hidden. The commenter 
states that normal operation of the thrust reverser will indicate if 
the sync-lock system is active, and whenever the sync-lock system is 
not available, either the unlock indicator on the external surface of 
the engine cowling will indicate this condition or the thrust reverser 
will not deploy on request.
    4. One commenter asks why operational checks would be required at 
more frequent intervals following installation of an additional safety 
feature than prior to its installation.
    The FAA recognizes the concerns of these commenters regarding the 
requirement for periodic operational checks of the sync-lock following 
its installation. However, the FAA finds that the operational checks 
are necessary in order to provide an adequate level of safety and to 
ensure the integrity of the sync-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 ATA, 
have participated in various discussions and work activities resulting 
from the recommendations of the task force.
    The FAA acknowledges that the operational checks specified in this 
AD and CMR items are similar in terms of scheduled maintenance and 
recordkeeping. This AD addresses an unsafe condition and requires 
installation of the sync-lock to correct that unsafe condition. The FAA 
has determined that the requirement for operational checks is necessary 
in order to ensure the effectiveness of that installation in addressing 
the unsafe condition. This determination is based on the fact that the 
sync-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 sync-lock that 
may not be evident during normal operation of the thrust reverser 
system and may not result in activation of the sync-lock ``unlock'' 
indicator. The ATA's suggested alternative to accomplishment of the 
operational checks would permit each operator to determine whether and 
how often these checks 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 
checks of the integrity of the sync-lock installation in a common 
manner and at common intervals.
    The FAA also finds that addressing operational checks of the sync-
lock integrity in a recommended action, such as an MRB report, will not 
ensure an acceptable level of safety with regard to the thrust reverser 
system. However, the FAA recognizes that an operational check interval 
of 4,000 hours time-in-service, which will be recommended by Boeing for 
inclusion in the next revision to the MRB report, corresponds more 
closely to the interval at which most of the affected operators conduct 
regularly scheduled ``C'' checks. The FAA has reconsidered the proposed 
interval of 1,000 hours time-in-service for accomplishment of 
repetitive operational checks. In light of the safety implications of 
the unsafe condition addressed and the practical aspects of 
accomplishing orderly operational checks 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 checks at intervals of 4,000 hours time-in-service will provide 
an acceptable level of safety. Paragraph (c) of the final rule has been 
revised accordingly.
    Boeing requests that specific references to page numbers and 
revision dates of the Boeing 757 Airplane Maintenance Manual (AMM) be 
eliminated from paragraphs (a)(1), (a)(2), (c)(1), and (c)(2) of the 
AD. Boeing recommends that the proposed AD specify only the ATA 
Chapter-Section-Subject pageblock title and task title in these 
paragraphs. A second commenter states that the referenced pages could 
not be found in its latest copy of the AMM.
    Boeing explains that the AMM's are customized for each operator to 
reflect all of the equipment in that operator's fleet. Therefore, the 
number of pages for any given procedure is variable, depending on the 
number of different equipment configurations documented in an 
operator's AMM. Boeing also indicates that AMM procedures are revised 
periodically for non-technical reasons. Boeing adds that changes to the 
structure of the procedures are necessary to accommodate an upgrade of 
the publishing system that is currently under way, which, in addition 
to repagination, will necessitate the issuance of revised AMM pages.
    Boeing states that the effect of specifying AMM page numbers and 
revision dates in the AD is that operators may be unable to use the 
procedure contained in the AMM to perform certain tests required by the 
AD. Each operator would be required to maintain an obsolete version of 
the procedure, or to request FAA approval of an alternative method of 
compliance with the AD that would allow the use of the current version 
of the AMM.
    The FAA concurs partially. In light of the information submitted by 
the commenter, the FAA finds that specific AMM page numbers and dates 
should not be specified in the final rule. Therefore, such references 
have been removed from paragraphs (a)(1) and (a)(2) of the final rule. 
However, for those paragraphs, the FAA does not agree that copies of 
the specific procedures should be included in the final rule. 
Therefore, paragraphs (a)(1) and (a)(2) of the final rule have been 
revised to cite only the appropriate section and task title specified 
in the AMM for accomplishment of the tests required by those 
paragraphs.
    The FAA's objective in proposing periodic operational checks of the 
sync-lock device, as specified in paragraph (c) of this AD, is to 
ensure the integrity of the locking function. However, subsequent to 
the issuance of the proposal and the receipt of Boeing's comments to 
the proposal, Boeing has submitted to the FAA separate procedures for 
accomplishment of the operational check of the sync-lock integrity. 
These procedures have been defined in paragraph (c) of the final rule; 
therefore, the AMM references specified in paragraph (c) of the NPRM 
have been removed from the final rule. Additionally, the procedures for 
the operational checks are accomplished independently of the other 
thrust reverser system tests specified in paragraph (c) of the 
proposal. Accordingly, the FAA has revised paragraph (c) of the final 
rule to require periodic accomplishment of operational checks of the 
sync-lock integrity only, and has removed the requirement for 
accomplishment of other tests specified in that paragraph of the 
proposal.
    Since the issuance of the proposed rule, Boeing has issued Revision 
2 of Service Bulletin 757-78-0032, dated May 12, 1994. The service 
bulletin revision moves general work instruction Step B from Work 
Package 2 to Step U in Work Package 8. In Revision 1 of the service 
bulletin, Step B of Work Package 2 specified procedures for removal of 
the ground to the EICAS for the REV ISLN VAL message; however, the 
ground should not be removed as part of Work Package 2. Rather, the 
ground should be removed as part of Work Package 8 in order to avoid 
loss of the REV ISLN VAL message on EICAS. Revision 2 of the service 
bulletin correctly describes procedures for removal of the ground as 
part of Work Package 8. Revision 2 of the service bulletin also 
describes procedures for installation of an additional bracket on the 
P36 disconnect bracket and to make a cutout on the P37 disconnect 
bracket on certain airplanes.
    The FAA has reviewed and approved this latest revision to the 
service bulletin and has revised the final rule to reflect it as the 
appropriate source of service information. The FAA finds that citing 
this latest revision to the service bulletin will impose no additional 
burden on any operator.
    It should be noted that Revision 2 of Boeing Service Bulletin 757-
78-0032 references Rolls-Royce Service Bulletins RB.211-78-9627 and 
RB.211-78-9613 as additional sources of service information for 
accomplishment of the originally proposed sync-lock installation. 
However, the Boeing service bulletin does not specify the appropriate 
revision levels for the Rolls-Royce service bulletins. Therefore, the 
FAA has added ``NOTE 1'' to paragraph (b) of this AD to specify that 
the intent of that paragraph is that the appropriate revision levels 
for the Rolls-Royce service bulletins that are to be used in 
conjunction with Boeing Service Bulletin 757-78-0032 are as follows: 
Rolls-Royce Service Bulletin RB.211-78-9613, dated December 3, 1992, or 
Revision 1, dated March 5, 1993, or Revision 2, dated October 1, 1993; 
and Rolls-Royce Service Bulletin RB.211-78-9627, dated December 3, 
1992.
    In addition, since the issuance of the proposed rule, Rolls-Royce 
has issued Service Bulletin RB.211-78-9822, dated October 1, 1993. This 
service bulletin describes procedures for installation of a revised 
thrust reverser sync-lock. The FAA has determined that accomplishment 
of the actions described in this service bulletin, in conjunction with 
Boeing Service Bulletin 757-78-0032 [which was cited in paragraph (b) 
of the proposal as the appropriate source of service information for 
installation of an additional thrust reverser system locking feature], 
constitutes an acceptable alternative to the sync-lock installation 
specified in paragraph (b) of the proposal.
    In light of this information, paragraph (b) of the final rule has 
been revised to include paragraph (b)(1), which contains the 
requirement for installation of an additional thrust reverser system 
locking feature that was specified in the proposed rule, and paragraph 
(b)(2), which provides for installation of a revised thrust reverser 
sync-lock as an acceptable alternative to paragraph (b)(1) of this AD. 
Accomplishment of the revised installation specified in paragraph 
(b)(2) requires no additional work hours beyond the 506 work hours 
specified in the economic impact information, below, for accomplishment 
of the originally proposed sync-lock installation.
    Additionally, it should be noted that Rolls-Royce Service Bulletin 
RB.211-78-9822 references Rolls-Royce Service Bulletin RB.211-78-9613 
as an additional source of service information for airplanes equipped 
with Rolls-Royce RB211-535E4/E4B engines. Rolls-Royce Service Bulletin 
RB.211-78-9613 references Rolls-Royce Service Bulletin RB.211-78-9627 
as an additional source of service information. However, the 
appropriate revision levels for these service bulletins are not 
specified in Boeing Service Bulletin 757-78-0032 or in any of the 
Rolls-Royce service bulletins. Therefore, the FAA has added ``NOTE 2'' 
to paragraph (b) of the final rule to specify that the appropriate 
revision levels to be used in conjunction with Rolls-Royce Service 
Bulletin RB.211-78-9822 are as follows: Rolls-Royce Service Bulletin 
RB.211-78-9613, Revision 2, dated October 1, 1993; and Rolls-Royce 
Service Bulletin RB.211-78-9627, dated December 3, 1992.
    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 250 Model 757 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 95 
airplanes of U.S. registry will be required to accomplish the restow 
and integrity tests required by this AD, that it will take 
approximately 1 work hour per airplane to accomplish those tests, and 
that the average labor rate is $55 per work hour. Based on these 
figures, the total cost impact of the AD on U.S. operators to 
accomplish each operational test is estimated to be $5,225, or $55 per 
airplane.
    The FAA estimates that 95 airplanes of U.S. registry will be 
required to accomplish either modification specified in paragraphs 
(b)(1) and (b)(2) of this AD. It will take approximately 506 work hours 
per airplane to accomplish either of those modifications, and the 
average labor rate is $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 the AD on U.S. operators to 
accomplish the modification is estimated to be $2,643,850, or $27,830 
per airplane.
    The FAA also estimates that 113 airplanes of U.S. registry will be 
required to accomplish the periodic operational tests of the sync-lock 
installation required by this AD, that it will take approximately 1 
work hour per airplane to accomplish each test, and that the average 
labor rate is $55 per work hour. Based on these figures, the total cost 
impact of the AD on U.S. operators to accomplish each operational test 
is estimated to be $6,215, or $55 per airplane.
    Based on these figures, the total cost impact of the AD on U.S. 
operators is estimated to be $2,655,290.
    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 FAA recognizes that the modification will require a large 
number of work hours to accomplish. However, the 5-year compliance time 
specified in paragraph (b) of this AD should allow ample time for the 
sync-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 14 CFR part 
39 of the Federal Aviation Regulations 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:

94-13-02  Boeing: Amendment 39-8942. Docket 93-NM-111-AD.

    Applicability: Model 757 series airplanes equipped with Rolls-
Royce RB211-535E4/E4B engines; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent deployment of a thrust reverser in flight and 
subsequent reduced controllability of the airplane, accomplish the 
following:
    (a) For airplanes on which the sync-lock feature was not 
installed during production or as a modification in accordance with 
Boeing Service Bulletin 757-78-0032: Within 4,000 hours time-in-
service after the effective date of this AD; and thereafter at 
intervals not to exceed 4,000 hours time-in-service until the 
modification required by paragraph (b) of this AD is accomplished; 
accomplish paragraphs (a)(1) and (a)(2) of this AD to verify proper 
operation of the thrust reverser system. Prior to further flight, 
repair any discrepancy found, in accordance with the procedures 
described in the Boeing 757 Maintenance Manual.
    (1) Perform a ``Thrust Reverser-Auto Restow Test'' in accordance 
with the procedures described in Section 78-31-00 of the Boeing 757 
Maintenance Manual.
    (2) Perform an ``Actuator Lock and Crossover Shaft Integrity 
Test'' in accordance with the procedures described in Section 78-31-
00 of the Boeing 757 Maintenance Manual.
    (b) For airplanes on which the sync-lock feature was not 
installed during production or as a modification in accordance with 
Boeing Service Bulletin 757-78-0032: Within 5 years after the 
effective date of this AD, accomplish the requirements of either 
paragraph (b)(1) or (b)(2) of this AD. Accomplishment of either of 
these installations constitutes terminating action for the tests 
required by paragraph (a) of this AD.
    (1) Install an additional thrust reverser system locking feature 
(sync-lock installation) in accordance with Boeing Service Bulletin 
757-78-0032, Revision 2, dated May 12, 1994.

    Note 1: Revision 2 of Boeing Service Bulletin 757-78-0032 
references Rolls-Royce Service Bulletins RB.211-78-9613 and RB.211-
78-9627 as additional sources of service information. The intent of 
paragraph (b)(1) of this AD is that the appropriate revision levels 
of the Rolls-Royce service bulletins to be used in conjunction with 
Boeing Service Bulletin 757-78-0032 are as follows: Rolls-Royce 
Service Bulletin RB.211-78-9613, dated December 3, 1992, or Revision 
1, dated March 5, 1993, or Revision 2, dated October 1, 1993; and 
Rolls-Royce Service Bulletin RB.211-78-9627, dated December 3, 1992.

    (2) Install a revised thrust reverser sync-lock in accordance 
with Boeing Service Bulletin 757-78-0032, Revision 2, dated May 12, 
1994, and Rolls-Royce Service Bulletin RB.211-78-9822, dated October 
1, 1993.

    Note 2: Rolls-Royce Service Bulletin RB.211-78-9822 references 
Rolls-Royce Service Bulletin RB.211-78-9613 as an additional source 
of service information for airplanes equipped with Rolls-Royce 
RB211-535E4/E4B engines. Rolls-Royce Service Bulletin RB.211-78-9613 
references Rolls-Royce Service Bulletin RB.211-78-9627 as an 
additional source of service information. The FAA's intent is that 
the appropriate revision levels to be used in conjunction with 
Rolls-Royce Service Bulletin RB.211-78-9822 are as follows: Rolls-
Royce Service Bulletin RB.211-78-9613, Revision 2, dated October 1, 
1993; and Rolls-Royce Service Bulletin RB.211-78-9627, dated 
December 3, 1992.

     -(c) Within 4,000 hours time-in-service after accomplishing the 
modification required by paragraph (b) of this AD, 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: Accomplish the ``Thrust Reverser Sync-Lock 
Integrity Test'' specified below to verify that the sync-locks have 
not failed in the ``unlocked'' state. Prior to further flight, 
repair any discrepancy found, in accordance with procedures 
described in the Boeing 757 Maintenance Manual.

Thrust Reverser Sync-Lock Integrity Test

1. General
    A. Use this procedure to test the integrity of the thrust 
reverser sync locks. The procedure must be performed on each engine.
2. Thrust Reverser Sync Lock Test
    A. Prepare for the thrust reverser sync lock test.
    (1) Open the AUTO SPEEDBRAKE circuit breaker on the overhead 
circuit breaker panel, P11.
    (2) Do steps 2.A.(2)(a) through 2.A.(2)(f) to supply power to 
the thrust reverser system:
    (a) Make sure the thrust levers are in the idle position.
    (b) Make sure the thrust reversers are retracted and locked.
    (c) Make sure these circuit breakers on the main power 
distribution panel, P6, are closed:
    1) L ENG SYNC LOCK
    2) R ENG SYNC LOCK-ALTN
    (d) Make sure these circuit breakers on the overhead circuit 
breaker panel, P11, are closed:
    1) LANDING GEAR POS SYS 1
    2) T/R IND R
    3) T/R CONT-ALTN-R
    4) T/R IND L
    5) T/R CONT L
    6) R ENG SYNC LOCK
    7) T/R CONT R
    8) EICAS CMPTR LEFT
    9) EICAS UPPER IND
    10) EICAS CMPTR RIGHT
    11) EICAS LOWER IND
    12) EICAS DISPLAY SW
    13) EICAS PILOTS DSP
    14) AIR/GND SYS 1
    15) AIR/GND SYS 2
    16) LANDING GEAR POS SYS 2
    17) PROX SW TEST
    (e) Supply electrical power.
    (f) Supply pressure to the left (for the left engine) or right 
(for the right engine) hydraulic system.
    B. Do the thrust reverser sync lock test.
    (1) Use the SENSOR CHANNEL SELECT thumb switches to set the PSEU 
code for the auto-restow proximity sensor.
    (a) On PSEU (-17), The left engine code is 433.
    (b) On PSEU (-16), The left engine code is 105.
    (c) The right engine PSEU code is 099.

    Note: Step 2.B.(2) will cause the Hydraulic Isolation Valve 
(HIV) to open for approximately 5 seconds. Steps 2.B.(3) through 
2.B.(5) must be done during this 5 second time. Steps 2.B.(2) 
through 2.B.(5) may be repeated if necessary.
    (2) Push the TARGET TEST switch on the PSEU and hold for one 
second.
    (3) Make sure the TARGET NEAR light on the PSEU comes on after 
approximately four seconds.
    (4) Make sure that the EICAS Advisory message L(R) REV ISLN VAL 
shows for approximately 3 seconds and then does not show.
    (5) Make sure the sync lock manual unlock lever on the right 
sleeve of the reverser does not extend.
    (6) Push and release the RESET switch on the PSEU.
    (7) Open the applicable circuit breaker(s):
    (a) For the left engine; L ENG SYNC LOCK (Panel P6)
    (b) For the right engine; R ENG SYNC LOCK (Panel P11) R ENG SYNC 
LOCK-ALTN (Panel P6)
    (8) Move the left (right) reverse thrust lever up and rearward 
to the reverse thrust position.
    (9) Make sure that the thrust reverser does not extend.
    (10) Move the left (right) reverse thrust lever to the forward 
and down position.
    C. Put the airplane back to its usual condition.
    (1) Remove hydraulic pressure.
    (2) Close the applicable circuit breaker(s).
    (a) For the left engine; L ENG SYNC LOCK (Panel P6)
    (b) For the right engine; R ENG SYNC LOCK (Panel P11) R ENG SYNC 
LOCK-ALTN (Panel P6)
    (3) Close the AUTO SPEEDBRAKE circuit breaker on the overhead 
circuit breaker panel, P11.
    (4) Remove electrical power.
    D. Repeat the thrust reverser sync lock test on the other 
engine.

    (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.

    (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.
    (f) The modification shall be done in accordance with Boeing 
Service Bulletin 757-78-0032, Revision 2, dated May 12, 1994; and/or 
Rolls-Royce Service Bulletin RB.211-78-9822, dated October 1, 1993. 
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; and Rolls-Royce plc, 
P.O. Box 31, Derby DE24 8BJ, England, ATTN: Technical Publications 
Department. 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 July 20, 1994.

    Issued in Renton, Washington, on June 13, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-14755 Filed 6-17-94; 8:45 am]
BILLING CODE 4910-13-U