Commercial

Airplane

Group

767

Service Bulletin

ALERT

Number: 767-78A0088 Summary Date: April 19, 2001

ATA System: 7800

SUBJECT: EXHAUST (CF6-80C2 Engines) - Thrust Reverser - Thrust Reverser Control System - Center

Drive Unit (CDU) Cone Brake and Electro-Mechanical Brake Integrity Tests

CONCURRENT REQUIREMENTS

None

BACKGROUND

This inspection will make sure that the center drive

unit (CDU) cone brake and the Thrust Reverser

Actuation System (TRAS) brake have the holding

torque required to prevent any uncommanded thrust

reverser sleeve movement.

The CDU cone brake and the TRAS brake are

primary safety devices required to prevent

inadvertent thrust reverser sleeve movement. To

meet the system reliability requirements, periodic

torque checks are required to ensure the integrity of

these locking devices. A failure of either of these

locks is not detected during normal operation. The

torque check intervals have been determined

through industry-wide accepted probability and

reliability methods.

The TRAS lock is a solenoid activated disk brake

this is connected to the upper angle gearbox by a

flexible drive shaft. The brake is released when 28

VDC is applied from the control circuit and is locked

at all other times. Low torque can be the result of a

brake or flexible shaft failure.

The CDU cone brake is a spring load, unidirectional

device that prevent rotation of the air motor in the

deploy direction. The cone brake always allows the

air motor to rotate in the stow direction. The brake

is disengaged when the directional control valve

actuator piston is commanded to the deploy position

from the control circuit.

ACTION

On each thrust reverser half, do a functional test of

the Electro-Mechanical brake and CDU cone brake

to verify the holding torque.

EFFECTIVITY

All 767-400ER airplanes powered by CF6-80C2

engines.

COMPLIANCE

Boeing recommends the operators do this service

bulletin within 650 flight hours after receipt of this

service bulletin.

Boeing recommends the operators repeat the

Electro-Mechanical brake and CDU cone brake tests

every 1,000 flight hours.

Federal Aviation Administration (FAA) Airworthiness

Directive (AD) 2000-09-04, Amendment 39-11712,

is related to this service bulletin.

INDUSTRY SUPPORT INFORMATION

Boeing warranty remedies are not available for the

inspection given in this service bulletin.

MANPOWER

Total Man-hours - 6 for each airplane

Elapsed Time - 3 Hours

MATERIAL INFORMATION

None

767-78A0088

Summary Page 1 of 2
ALERT BOEING SERVICE BULLETIN 767-78A0088 ALERT

ELECTRO-MECHANICAL BRAKE

DO A FUNCTIONAL TEST ON THE

FOR EACH THRUST REVERSER HALF:

DO A FUNCTIONAL TEST ON THE

FOR EACH THRUST REVERSER HALF:

CENTER DRIVE UNIT (CDU) CONE BRAKE

RIGHT SIDE OPPOSITE

LEFT SIDE SHOWN,

V41557

April 19, 2001 767-78A0088

Summary Page 2 of 2
Commercial

Airplane

Group

767

Service Bulletin

ALERT

Number: 767-78A0088

Date: April 19, 2001

ATA System: 7800

SUBJECT: EXHAUST (CF6-80C2 Engines) - Thrust Reverser - Thrust Reverser Control System - Center

Drive Unit (CDU) Cone Brake and Electro-Mechanical Brake Integrity Tests

1. PLANNING INFORMATION

A. Effectivity

NOTE: * THIS EFFECTIVITY INCLUDES ALL FUTURE 767-400ER AIRPLANES WITH CF6-80C2

ENGINES, EVEN IF THEY ARE NOT LISTED IN THIS SECTION.

1. Airplanes

Refer to Service Bulletin Index Document D624T001, Part 3 for Airplane Variable Number, Line

Number, and Serial Number data.

This service bulletin is for the airplanes shown below.

Airplane Models:

767-400ER

IDENTIFICATION BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER *

CONTINENTAL AIRLINES (CAL)

VQ071-VQ075

DELTA AIR LINES (DAL)

VQ001-VQ016

IDENTIFICATION BY VARIABLE NUMBER

VQ001-VQ016 VQ071-VQ075

2. Spares Affected

None

April 19, 2001 767-78A0088

Page 1 of 10
ALERT BOEING SERVICE BULLETIN 767-78A0088 ALERT

B. Concurrent Requirements

None

C. Reason

This inspection will make sure that the center drive unit (CDU) cone brake and the Thrust Reverser

Actuation System (TRAS) brake have the holding torque required to prevent any uncommanded

thrust reverser sleeve movement.

The CDU cone brake and the TRAS brake are primary safety devices required to prevent inadvertent

thrust reverser sleeve movement. To meet the system reliability requirements, periodic torque

checks are required to ensure the integrity of these locking devices. A failure of either of these locks

is not detected during normal operation. The torque check intervals have been determined through

industry-wide accepted probability and reliability methods.

The TRAS lock is a solenoid activated disk brake this is connected to the upper angle gearbox by a

flexible drive shaft. The brake is released when 28 VDC is applied from the control circuit and is

locked at all other times. Low torque can be the result of a brake or flexible shaft failure.

The CDU cone brake is a spring load, unidirectional device that prevent rotation of the air motor in the

deploy direction. The cone brake always allows the air motor to rotate in the stow direction. The

brake is disengaged when the directional control valve actuator piston is commanded to the deploy

position from the control circuit.

D. Description

On each thrust reverser half, do a functional test of the Electro-Mechanical brake and CDU cone

brake to verify the holding torque.

An evaluation form is attached to this service bulletin. Please use this form to tell us what you think

of the quality of this service bulletin.

E. Compliance

Boeing recommends the operators do this service bulletin within 650 flight hours after receipt of this

service bulletin.

Boeing recommends the operators repeat the Electro-Mechanical brake and CDU cone brake tests

every 1,000 flight hours.

Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2000-09-04, Amendment

39-11712, is related to this service bulletin.

F. Approval

NOTE: Joint Airworthiness Requirements (JAR) compliance status may be found in the Service

Bulletin Index, Part 1.

This service bulletin was examined by the Federal Aviation Administration (FAA). The changes

specified in this service bulletin comply with the applicable Federal Aviation Regulations (FAR) and

are FAA approved. This service bulletin and the FAA approval were based on the airplane in its

original Boeing delivery configuration or as modified by other FAA approved Boeing changes.

If an airplane has a non-Boeing modification or repair that affects a component or system also

affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory

agency approval before incorporating this service bulletin.

April 19, 2001 767-78A0088

2
ALERT BOEING SERVICE BULLETIN 767-78A0088 ALERT

This service bulletin has been approved by the FAA. In addition, the Manager of the FAA Seattle

Aircraft Certification Office approves the inspection and tests defined in this service bulletin as an

alternative method of compliance to the requirements of paragraphs (d)(2), (f) and (g) of AD

2000-09-04. All provisions of AD 2000-09-04 that are not specifically referenced in the above

sentence remain fully applicable and must be complied with.

G. Manpower

The table below shows an estimate of the man-hours necessary to do this change for each airplane.

This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator

man-hour data if necessary. The estimate does not include lost time. These are some examples of

lost time:

- Time to adjust to the workplace

- Time to schedule the work

- Time to examine the work

- Time to cure the materials

- Time to make the parts

- Time to find the tools.

Task Number of Persons Man-Hours Elapsed Time (Hours)

Test 2 6 3

TOTAL FOR EACH AIRPLANE 6 3

H. Weight and Balance Changes

None

I. Electrical Load Data

Not changed

J. References

1. Existing Data:

a. 767 Maintenance Manual (AMM) Subject 71-11-04, 78-31-21

2. Data supplied with this service bulletin:

None

3. Installation Drawings Used in the Preparation of This Service Bulletin:

None

April 19, 2001 767-78A0088

3
ALERT BOEING SERVICE BULLETIN 767-78A0088 ALERT

K. Publications Changed

None

L. Interchangeability and Intermixability of Parts

Refer to Paragraph 2.E., Existing Parts Accountability, for interchangeability and intermixability

information.

April 19, 2001 767-78A0088

4
ALERT BOEING SERVICE BULLETIN 767-78A0088 ALERT

2. MATERIAL INFORMATION

A. Material - Price and Availability

None

B. Industry Support Information

Boeing warranty remedies are not available for the inspection given in this service bulletin.

C. Parts Necessary For Each Airplane

Parts and Materials Supplied by the Operator:

QTY Part Number Name

4 126784-() Center Drive Unit (a)

(a) Replace this part when the holding torque is less than 15 pound inches.

D. Parts Necessary to Change Spares

None

E. Existing Parts Accountability

None

F. Special Tooling - Price and Availability

None

G. Special Tooling Necessary to do this Service Bulletin

No special tools or equipment are necessary to do the change in this service bulletin. But,

maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be

necessary. Examine operator tool supply to make sure all necessary tools are available.

April 19, 2001 767-78A0088

5
ALERT BOEING SERVICE BULLETIN 767-78A0088 ALERT

BLANK PAGE

April 19, 2001 767-78A0088

6
ALERT BOEING SERVICE BULLETIN 767-78A0088 ALERT

3. ACCOMPLISHMENT INSTRUCTIONS

GENERAL NOTES

1. The lettered paragraphs contain the tests to be accomplished at the specifies interval.

2. Obey all of the warnings and cautions given in the specified manual sections.

3. Repeat the Electro-Mechanical brake and CDU cone brake tests every 1,000 flight hours.

WORK INSTRUCTIONS

A. Do the functional test on both thrust reverser for the Electro-Mechanical brakes of both engines as

follows:

1. Open the engine fan cowl panels as shown in 767 Maintenance Manual Subject 71-11-04 or

your own equivalent procedure.

2. Do a check of the running torque of the thrust reverser system:

a. Manually extend the thrust reverser six inches and measure the running torque. Make sure

the torque is less than 10 pound-inches.

3. Do a check of the electro-mechanical brake holding torque:

a. Make sure the thrust reverser translating cowl is extended at least one inch.

b. Make sure the CDU lock handle is released.

c. Pull down on the manual release handle on the electro-mechanical brake until the handle

fully engages the retaining clip.

NOTE: This will lock the electro-mechanical brake.

d. With the manual drive lockout cover removed from the CDU, install a 1/4-inch extension tool

and dial -type torque wrench into the drive pad.

NOTE: You will need a 24-inch extension to provide adequate clearance for the torque

wrench.

e. Apply 90 pound-inches of torque to the system.

1) The electro-mechanical brake system is working correctly if the torque is reached before

you turn the wrench 450 degrees (1-1/4 turns).

2) If the flexshaft turns more than 450 degrees (1-1/4 turns) before you reach the specified

torque, you must replace the long flexshaft between the CDU and the upper angle

gearbox.

3) If you do not get 90 pound-inches of torque, inspect the short flexshaft between the

upper angle gearbox and the electro-mechanical brake. If the flexshaft is twisted, broken

or otherwise damaged, replace the flexshaft and repeat (e). If you still do not get 90

pound-inches of torque, you must replace the electro-mechanical brake.

f. Release the torque by turning the wrench in the position direction until you read zero

pound-inches.

April 19, 2001 767-78A0088

7
ALERT BOEING SERVICE BULLETIN 767-78A0088 ALERT

1) If the wrench does not turn to within 30 degrees of initial starting point, you must replace

the long flexshaft between the CDU and upper angle gearbox.

4. Fully retract the thrust reverser.

5. Repeat this procedure on other reverser half and on the remaining engines.

6. End the Electro-Mechanical brake check.

B. Repeat the Electro-Mechanical brake test at 1,000 flight hours intervals

C. Do the functional test on both thrust reverser for the Center Drive Unit (CDU) cone brakes of both

engines as follows:

1. Pull up on the manual release handle to unlock the electro-mechanical brake.

2. Pull the manual brake release lever on the CDU to release the cone brake. Refer to Figure 1

for location.

NOTE: This will release the pre-load tension that may occur during a stow cycle.

3. Return the manual brake release lever to the locked position to engage the cone brake. Refer

to Figure 1 for location.

4. Remove the two bolts that hold the lockout plate to the CDU and remove the lockout plate.

Refer to Figure 1 for location.

5. Install a 1/4-inch drive and a dial-type torque wrench into the CDU drive pad.

WARNING: Do not use more than 100 pound-inches of torque when carrying out this check.

Excessive torque will damage the CDU.

6. Turn the torque wrench to try to manually extend the translating cowl until you get at least 15

pound-inches of torque.

NOTE: The cone brake prevents movement in the extend direction only. If you try to measure

the torque in the retract direction, you will get a false reading.

7. If the sleeve translates to deploy with a torque less than 15 pound inches you must replace the

CDU. Refer to 767 Maintenance Manual Subject 78-31-21.

8. Reinstall the lockout plate.

9. Fully retract the thrust reverser.

10. Pull down on the manual release handle on the electro-mechanical brake until the handle fully

engages the retaining clip.

NOTE: This will lock the electro-mechanical brake.

11. Repeat this procedure on other reverser half and on the remaining engines.

12. Close the engine fan cowl panels as shown in 767 Maintenance Manual Subject 71-11-04 or

your own equivalent procedure.

13. End the CDU cone brake check.

D. Repeat CDU cone brake test every 1,000 flight hours.

April 19, 2001 767-78A0088

8
ALERT BOEING SERVICE BULLETIN 767-78A0088 ALERT

FIGURE TABLE OF CONTENTS

Title Page

FIGURE 1. ELECTRO-MECHANICAL BRAKE, CDU MANUAL BRAKE RELEASE

LEVER, LOCKOUT PLATE AND DRIVE PAD LOCATIONS . . . . . . . . . . . . . 10

April 19, 2001 767-78A0088

9
ALERT BOEING SERVICE BULLETIN 767-78A0088 ALERT

UPPER ANGLE GEARBOX

ELECTRO-MECHANICAL BRAKE

(LEFT SIDE SHOWN,

RIGHT SIDE TURNED 180 DEGREES)

CENTER

(CDU)

DRIVE UNIT

DRIVE PAD

PLATE AND

LOCKOUT

BRAKE RELEASE

CDU MANUAL

LEVER

CENTER DRIVE UNIT

V41558

FIGURE 1. ELECTRO-MECHANICAL BRAKE, CDU MANUAL BRAKE RELEASE LEVER, LOCKOUT

PLATE AND DRIVE PAD LOCATIONS

April 19, 2001 SHEET 1 OF 1 767-78A0088

10
Commercial

Airplane

Group

767

Service Bulletin

Number: 767-78A0088 Evaluation Form

Date: April 19, 2001

ATA System: 7800

Prepared By: Phuoc Tran

SUBJECT: EXHAUST (CF6-80C2 Engines) - Thrust Reverser - Thrust Reverser Control System - Center

Drive Unit (CDU) Cone Brake and Electro-Mechanical Brake Integrity Tests

Use this evaluation form to tell us what you think of the quality of this service bulletin. We will use the data

that you give us to improve the quality of our service bulletins.

NOTE: Please do not use this evaluation form to tell us to make changes to your manuals. To make these

changes, please use a Publication Change Request (PCR) form.

Please give us this data:

(If necessary, please use the other side. Thank you for the time you used to give us your comments.)

OPERATOR: TODAY'S DATE:

PREPARED BY: TITLE:

ORGANIZATION: TELEX CODE:

TELEPHONE NUMBER: BASE:

Please rate the quality of this service bulletin: (good) 4321 (poor)

Please rate the quality of the illustrations: (good) 4321 (poor)

Will you do the change given by this service bulletin? Yes No If not, please explain:

Is this service bulletin easy to understand? Yes No If not, please explain:

Is this service bulletin easy to use? Yes No If not, please explain:

Are the Planning Information, Material Information, and

Accomplishment Instructions accurate? Yes No If not, please explain:

Is the Manpower estimate accurate? Yes No If not, please explain:

Give the completed evaluation form to your Boeing Field Service Representative or send the evaluation form

directly to this address:

Manager

Service Bulletin Engineering

Boeing Commercial Airplane Group

P.O. Box 3707, Mail Stop 2H-37

Seattle, WA 98124-2207