Airworthiness Directives; Boeing Model 767 Series Airplanes Equipped With Rolls-Royce RB211-524 Series Engines

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 92-NM-237-AD; Amendment 39-8998; AD 94-17-03]

Airworthiness Directives; Boeing Model 767 Series Airplanes

Equipped With Rolls-Royce RB211-524 Series 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 767 series airplanes, that requires

inspections, adjustments, and functional checks of the thrust reverser

system; installation of a terminating modification; and repetitive

operational checks of the gearbox locks and the air motor brake

following accomplishment of the modification. 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 that exist in the

current thrust reverser control system, which could result in an

inadvertent deployment of a thrust reverser during flight.

DATES: Effective September 14, 1994.

The incorporation by reference of certain publications, as listed

in the regulations, is approved by the Director of the Federal Register

as of September 14, 1994.

The incorporation by reference of Boeing Service Bulletin 767-78-

0048, dated August 15, 1991, listed in the regulations was approved

previously by the Director of the Federal Register as of October 15,

1991 (56 FR 51638, October 15, 1991).

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: Lanny Pinkstaff, Aerospace Engineer,

Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate,

Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,

Washington 98055-4056; telephone (206) 227-2684; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION:

A proposal to amend part 39 of the Federal Aviation Regulations (14

CFR part 39) to include an airworthiness directive (AD) that is

applicable to certain Boeing Model 767 series airplanes was published

in the Federal Register on August 6, 1993 (58 FR 42032). That action

proposed to supersede AD 91-22-02, Amendment 39-8062 (56 FR 51638,

October 15, 1991), to require inspections, adjustments, and functional

checks of the thrust reverser system on Model 767 series airplanes

equipped with Rolls-Royce RB211-524 or General Electric CF6-80C2 series

engines. That action also proposed to require installation of a

terminating modification and repetitive operational checks of the

gearbox locks and the air motor brake following accomplishment of that

modification on Model 767 series airplanes equipped with Rolls- Royce

RB211-524 series engines.

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 one of

its members, requests that two immediately adopted rules be created

from this proposed rule: one for airplanes equipped with Rolls-Royce

RB211-524 series engines, and the other for the airplanes equipped with

General Electric CF6-80C2 series engines. If either of the two rules

should be revised in the future, the superseded rule would only apply

to the operators actually affected, and operators having airplanes with

the other engine type would not be required to change their AD

compliance records.

The FAA concurs that two separate AD's should be created from the

proposal. Therefore, this final rule has been revised to require those

actions specified in the proposal for Model 767 series airplanes

equipped with Rolls-Royce RB211-524 series engines only. Paragraph (a)

of this final rule has been revised to specify that accomplishment of

the actions required by that paragraph terminates the actions required

by paragraph (a) of AD 91-22-02. Subsequently, the FAA may consider

superseding AD 91-22-02 to remove the requirements for Model 767 series

airplanes equipped with Rolls-Royce RB211-524 series engines from that

AD, to specify that those requirements are contained in this AD, and to

require accomplishment of a terminating modification for Model 767

series airplanes equipped with General Electric CF6-80C2 series engines

(once that modification becomes available).

The economic impact information, below, has also been revised to

specify the costs associated with accomplishment of the actions

required by this AD for those airplanes equipped with Rolls-Royce

RB211-524 series engines only.

Boeing requests that specific references to page numbers and

revision dates of the Boeing 767 Airplane Maintenance Manual (AMM) be

eliminated from the AD. Boeing recommends that the proposed AD specify

only the ATA Chapter-Section-Subject, pageblock, and task title. 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 agrees that specific AMM page numbers and dates

should not be specified in the final rule. However, the FAA does not

agree with the commenter's recommendation that the final rule specify

the ATA Chapter-Section-Subject, pageblock, and task title. The FAA's

objective in proposing periodic operational checks of the gearbox locks

and the air motor brake is to ensure the integrity of the locking

function. Since the issuance of the proposal and receipt of Boeing's

comments to the proposal, Boeing has submitted to the FAA separate

procedures for accomplishment of the operational check of the integrity

of the gearbox locks and the air motor brake. For clarification

purposes, the requirements of paragraph (d) of the proposal have been

separated into two paragraphs [(c) and (d)] of the final rule. The AMM

references specified in paragraph (c) of the proposal have been removed

from the final rule. Paragraph (d) of the final rule specifies that the

operational checks are required to be accomplished in accordance with

the procedures that appear in Appendix 1 (including Figure 1) of this

AD.

Since the issuance of the proposal, the FAA has reviewed and

approved Boeing Service Bulletin 767-78-0059, Revision 3, dated January

20, 1994, which adds a note in several locations to specify that

whenever a changed or disconnected connector is connected, an

inspection of the disconnected electrical connectors to detect bent or

pushed-back pins should be performed. This inspection is necessary

simply to verify the correct installation of the connectors; the FAA

does not consider that this inspection will impose an additional burden

on any operator. Additionally, the revised service bulletin references

the latest version of a particular wire kit to show changes in wiring

information. Paragraph (c) of the final rule has been revised to

reflect the latest revision of the service bulletin as an additional

source of service information.

It should be noted that Revisions 2 and 3 of Boeing Service

Bulletin 767-78-0059 reference Rolls-Royce Service Bulletins RB.211-71-

9608, RB.211-71-9600, and RB.211-71-9601, and Eldec Service Bulletin 8-

651-32-01 as additional sources of service information for

accomplishment of the locking gearbox installation. However, the Boeing

service bulletins do not specify the appropriate revision levels for

those Rolls-Royce and Eldec service bulletins. Therefore, the FAA has

added ``NOTE 1'' to paragraph (c) of this AD to specify that the intent

of that paragraph is that the appropriate revision levels for the

Rolls-Royce and Eldec service bulletins to be used in conjunction with

Boeing Service Bulletin 767-78-0059 are as follows: Rolls-Royce Service

Bulletin RB.211-71-9608, Revision 1, dated October 2, 1992; Rolls-Royce

Service Bulletin RB.211-71-9600, Revision 4, dated February 11, 1994;

Rolls-Royce Service Bulletin RB.211-71-9601, Revision 1, dated October

2, 1992; and Eldec Service Bulletin 8-651-32-01, dated January 31,

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.

Currently, there are no Model 767 series airplanes equipped with

Rolls-Royce RB211-524 series engines on the U.S. Register. However,

should an affected airplane be imported and placed on the U.S. Register

in the future, it will require approximately 22 work hours to

accomplish the inspections, adjustments, and functional checks, 754

work hours to accomplish the modification, and 1 work hour to

accomplish the operational checks of the modification, 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 for the required actions will be $42,735 per airplane.

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 adding the following new

airworthiness directive:

94-17-03 BOEING: Amendment 39-8998. Docket 92-NM-237-AD.

-Applicability: Model 767 series airplanes equipped with Rolls-

Royce RB211-524 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: -

(a) Within 30 days after October 15, 1991 (the effective date of

AD 91-22-02, Amendment 39-8062), perform the inspections,

adjustments, and functional checks described in Boeing Service

Bulletin 767-78-0048, dated August 15, 1991, or Revision 1, dated

March 26, 1992. Perform those actions in accordance with procedures

described in the service bulletin. After the effective date of this

AD, those actions shall be accomplished only in accordance with

Revision 1 of the service bulletin. Accomplishment of the actions

required by this paragraph terminates the actions required by

paragraph (a) of AD 91-22-02, amendment 39-8062. -

(1) Except as provided by paragraph (a)(2) of this AD, repeat

all inspections and functional checks in accordance with the service

bulletin at intervals not to exceed 3,000 flight hours. -

(2) Repeat the functional check of the grounding wire for the

thrust reverser Selector Sequence Valve (SSV) in accordance with the

service bulletin at intervals not to exceed 1,500 flight hours, and

whenever maintenance action is taken that would disturb the SSV

grounding circuit. -

(b) If any of the inspections and/or functional checks required

by paragraph (a) of this AD cannot be successfully performed, or if

those inspections and/or functional checks result in findings that

are unacceptable in accordance with Boeing Service Bulletin 767-78-

0048, dated August 15, 1991, or Revision 1, dated March 26, 1992,

accomplish paragraphs (b)(1) and (b)(2) of this AD. After the

effective date of this AD, the actions required by paragraph (b)(2)

of this AD shall be accomplished only in accordance with Boeing

Service Bulletin 767-78-0048, Revision 1, dated March 26, 1992. -

(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 11,

dated March 15, 1993. 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 767-78-0048, dated August

15, 1991, or Revision 1, dated March 26, 1992. Additionally, the

inspections and/or functional checks required by paragraph (a) of

this AD must be successfully accomplished; once this is

accomplished, the thrust reverser must then be reactivated. -

(c) Within 3 years after the effective date of this AD, install

a second locking gearbox system on the left- and right-hand engine

thrust reversers, in accordance with Boeing Service Bulletin 767-78-

0059, Revision 2, dated June 10, 1993; or Revision 3, dated January

20, 1994.

-Note 1: Revisions 2 and 3 of Boeing Service Bulletin 767-78-

0059 reference Rolls-Royce Service Bulletins RB.211-71-9608, RB.211-

71-9600, and RB.211-71-9601, and Eldec Service Bulletin 8-651-32-01

as additional sources of service information for accomplishment of

the locking gearbox installation. However, the Boeing service

bulletins do not specify the appropriate revision levels for those

Rolls-Royce and Eldec service bulletins. The appropriate revision

levels for the Rolls-Royce and Eldec service bulletins to be used in

conjunction with Boeing Service Bulletin 767-78-0059 are as follows:

Rolls-Royce Service Bulletin RB.211-71-9608, Revision 1, dated

October 2, 1992; Rolls-Royce Service Bulletin RB.211-71-9600,

Revision 4, dated February 11, 1994; Rolls-Royce Service Bulletin

RB.211-71-9601, Revision 1, dated October 2, 1992; and Eldec Service

Bulletin 8-651-32-01, dated January 31, 1992.

-(d) Within 3,000 flight hours after accomplishing the

modification required by paragraph (c) of this AD, or within 1,000

flight hours after the effective date of this AD, whichever occurs

later; and thereafter at intervals not to exceed 3,000 flight hours;

perform operational checks of the number 2 and number 3 gearbox

locks and of the air motor brake in accordance with Appendix 1

(including Figure 1) of this AD. -

(e) Accomplishment of the modification and periodic operational

checks required by paragraphs (c) and (d) of this AD constitutes

terminating action for the inspections, adjustments, and functional

checks required by paragraph (a) of this AD. -

(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 2: 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 (FAR)

(14 CFR 21.197 and 21.199) to operate the airplane to a location

where the requirements of this AD can be accomplished. -

(h) Certain actions shall be done in accordance with Boeing

Service Bulletin 767-78-0048, Revision 1, dated March 26, 1992; and

Boeing Service Bulletin 767-78-0059, Revision 2, dated June 10,

1993, or Boeing Service Bulletin 767-78-0059, Revision 3, dated

January 20, 1994. The incorporation by reference of these documents

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 767-78-0048,

dated August 15, 1991. The incorporation by reference of that

document 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

October 15, 1991 (56 FR 51638). 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 14, 1994.

Appendix 1

1. Gearbox Lock and Air Motor Brake Test

A. General

(1) To do the test of the gearbox Locks and air motor brake, you

must do the steps that follow:

(a) Do the deactivation procedure of the thrust reverser system.

(b) Do the test of the air motor brake.

(c) Do the test of the gearbox locks.

(d) Do the activation procedure of the thrust reverser system.

B. Equipment

(1) CP30784--INA Access Platform, Rolls-Royce

(2) CP30769--Protection Pads, Rolls-Royce

(3) CP30785--Access Stools, Rolls-Royce

(4) UT1293/1--Load Tool, Rolls-Royce (2 required)

C. Procedure (Fig. 1)

WARNING: DO THE DEACTIVATION PROCEDURE OF THE THRUST REVERSER

SYSTEM, WHICH MUST INCLUDE THE INSTALLATION OF LOCK BARS (OR

BLOCKERS), TO PREVENT THE ACCIDENTAL OPERATION OF THE THRUST

REVERSER. THE ACCIDENTAL OPERATION OF THE THRUST REVERSER COULD

CAUSE INJURY TO PERSONS AND DAMAGE TO EQUIPMENT.

(1) Do the deactivation procedure of the thrust reverser in the

forward thrust position for ground maintenance.

(2) Use of 0.25 inch (6.4 mm) square drive to turn the manual

lock release screw to release the No. 2 and No. 3 gearbox locks.

Note: It is not always easy to turn the manual lock release

screws. This is because of a preload in the system. To release the

preload, lightly turn the manual cycle and lockout shafts in the

stow direction.

(a) Make sure the lock indicators are extended at gearboxes No.

2 and No. 3.

(3) Do a test of the air motor brake:

(a) IF YOU USE THE LOAD TOOLS;

Try to move the translating cowl in the extend direction as

follows:

(1) Remove the lock bars that you installed in the deactivation

procedure.

(2) Install the load tools through the cutouts and into the No.

2 and No. 3 gearboxes.

(3) Attach the torque wrenches to the load tools.

(4) Try to move the translating cowl in the extend direction.

(b) IF YOU DO NOT USE THE LOAD TOOLS;

Try to move the translating cowl in the extends direction as

follows:

(1) Remove the lock bars that you installed in the deactivation

procedure.

(2) Put the 0.25 inch (6.4 mm) square drive extensions into the

manual cycle and lockout shaft at the No. 2 and No. 3 gearboxes.

(a) attach the standard drive tools.

(3) Try to move the translating cowl in the extend direction.

(c) If the translating cowl moves, replace the air motor and

shutoff valve.

(4) Do a test of the gearbox locks:

Note: The steps that follow are for the No. 3 gearbox. Then do

these steps again for the No. 2 gearbox.

(a) Install the lock bars in the manual cycle and lockout shafts

at the No. 2 and No. 3 gearboxes.

(b) Install the INA access platform in the exhaust mixer duct.

(c) Install the protection pads and the access stools.

(d) Release the air motor brake:

(1) Open the air motor access and pressure relief panel.

(2) Pull the air motor brake release handle forward and turn it

counterclockwise to lock the handle in its position.

(e) Turn the manual lock release screw clockwise to engage the

No. 3 gearbox lock.

(1) Make sure that the lock indicator is retracted (under the

surface) at gearbox No. 3.

(f) Make sure the No. 2 gearbox lock is released.

(1) Make sure the lock indicator is extended at gearbox No. 2.

(g) IF YOU USE THE LOAD TOOLS;

Do a check of the lock dogs as follows:

(1) Remove the lock bars from the No. 2 and No. 3 gearboxes.

(2) Install the load tool through the cutout and into the No. 3

gearbox.

(3) Attach the torque wrench to the load tool.

CAUTION: DO NOT APPLY A TORQUE LOAD OF MORE THAN 30 POUNDS-

INCHES (3.4 NEWTON-METERS) TO MANUAL CYCLE AND LOCKOUT SHAFT. A

LARGER TORQUE LOAD CAN CAUSE DAMAGE TO THE MECHANISM.

(4) Apply a torque counterclockwise through the manual wind

position of the No. 3 gearbox.

(a) If the translating cowl does not move, the lock bar touched

one of the two lock dogs.

(b) If the translating cowl moved, lock the thrust reverser

until the No. 3 gearbox is replaced.

(5) Turn the manual lock release screw counterclockwise to

release the gearbox lock.

(a) Make sure that the indication rod comes out of the No. 3

gearbox.

(6) Turn the manual cycle and lockout shaft counterclockwise a

\1/4\ of a turn.

(7) Turn the manual lock release screw clockwise to engage the

No. 3 gearbox lock.

(a) Make sure that the indication rod is fully retracted (under

the surface).

CAUTION: DO NOT APPLY A TORQUE LOAD OF MORE THAN 30 POUND-INCHES

(3.4 NEWTON-METERS) TO THE MANUAL CYCLE AND LOCKOUT SHAFT. A GREATER

TORQUE LOAD CAN CAUSE DAMAGE TO THE MECHANISM.

(8) Apply a torque counterclockwise through the manual wind

position of the No. 3 gearbox.

(a) If the manual cycle and lockout shaft can not be turned more

than approximately \1/4\ turn, the second lock dog is serviceable.

(b) If the manual cycle and lockout shaft can be turned more

than approximately \1/4\ turn, the second lock dog is unserviceable.

Lock the thrust reverser until the No. 3 gearbox is replaced.

Note: The two lock dogs are found \1/2\ turn apart when you use

the manual cycle and lockout shaft. It necessary, do the check again

to make sure that the lock dogs are serviceable.

(9) Do the procedure given above for the No. 2 gearbox lock.

(h) IF YOU DO NOT USE THE LOAD TOOLS; Do a check of the lock

dogs as follows:

(1) Remove the lock bars from the No. 2 and No. 3 gearboxes.

(2) Put the 0.25 inch (6.4 mm) square drive extensions into the

manual cycle and lockout shaft at the No. 2 and No. 3 gearboxes.

(a) Attach the standard drive tools.

CAUTION: DO NOT APPLY A TORQUE LOAD OF MORE THAN 30 POUND-INCHES

(3.4 NEWTON-METERS) TO THE MANUAL CYCLE AND LOCKOUT SHAFT. A LARGER

TORQUE LOAD CAN CAUSE DAMAGE TO THE MECHANISM.

(3) Apply a torque counterclockwise through the manual wind

position of the No. 3 gearbox.

(a) If the translating cowl does not move, the lock bar touched

one of the two lock dogs.

(b) If the translating cowl moved, lock the thrust reverser

until the No. 3 gearbox is replaced.

(4) Turn the manual lock release screw counterclockwise to

release the gearbox lock.

(a) Make sure that the indication rod comes out of the No. 3

gearbox.

(5) Turn the manual cycle and lockout shaft counterclockwise a

\1/4\ of a turn.

(6) Turn the manual lock release screw clockwise to engage the

No. 3 gearbox lock.

(a) Make sure that the indication rod is fully retracted (under

the surface).

CAUTION: DO NOT APPLY A TORQUE LOAD OF MORE THAN 30 POUND-INCHES

(3.4 NEWTON-METERS) TO THE MANUAL CYCLE AND LOCKOUT SHAFT. A GREATER

TORQUE LOAD CAN CAUSE DAMAGE TO THE MECHANISM.

(7) Apply a torque counterclockwise through the manual wind

position of the No. 3 gearbox.

(a) If the manual cycle and lockout shaft can not be turned more

than approximately \1/4\ turn, the second lock dog is serviceable.

(b) If the manual cycle and lockout shaft can be turned more

than approximately \1/4\ turn, the second lock dog is unserviceable.

Lock the thrust reverser until the No. 3 gearbox is replaced.

Note: The two lock dogs are found \1/2\ turn apart when you use

the manual cycle and lockout shaft. If necessary, do the check again

to make sure that the lock dogs are serviceable.

(8) Do the procedure given above for the No. 2 gearbox lock.

(5) Install the lock bars in the manual cycle and lockout shafts

at the No. 2 and No. 3 gearboxes.

(6) Apply the air motor manual brake:

(a) Turn the air motor brake release handle clockwise and then

release.

(b) Close the air motor access and pressure relief panel.

(7) Make sure the No. 2 and No. 3 gearbox locks are released.

(a) Make sure the lock indicator rods are extended at the No. 2

and No. 3 gearboxes.

(8) IF YOU USE THE LOAD TOOLS;

Try to move the translating cowl in the extend direction as

follows:

(a) Remove the lock bars from the No. 2 and No. 3 gearboxes.

(b) Install the load tools through the cutouts and into the No.

2 and No. 3 gearboxes.

(c) Attach the torque wrenches to the load tools.

(d) Try to move the translating cowl in the extend direction.

(9) IF YOU DO NOT USE THE LOAD TOOLS;

Try to move the translating cowl in the extend direction as

follows:

(a) Remove the lock bars from the No. 2 and No. 3 gearboxes.

(b) Put the 0.25 inch (6.4 mm) square drive extensions into the

manual cycle and lockout shaft at the No. 2 and No. 3 gearboxes.

(1) Attach the standard drive tools.

(c) Try to move the translating cowl in the extend direction.

(10) If the translating cowl moves, do the full test again.

(a) If the translating sleeve moves again, lock the thrust

reverser until you can replace the two locking gearboxes and the air

motor and shutoff valve.

(11) Remove the access tools and protection pads.

(12) Remove the INA access platform from the exhaust mixer duct.

(13) Do the activation procedure of the thrust reverser system.

(14) Do the functional test of the thrust reverser system.

BILLING CODE 4910-13-M

TR15AU94.000

BILLING CODE 4910-13-C

Issued in Renton, Washington, on August 4, 1994.

James V. Devany,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-19481 Filed 8-12-94; 8:45 am]

BILLING CODE 4910-13-U