Airworthiness Directives; Boeing Model 767 Series Airplanes Equipped with Pratt & Whitney JT9D-7R4 or General Electric CF6-80A Series Engines

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]

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