Motor to Start Aborted due to Bowed Rotor Overspeed

TASK 71-00-00-810-888-A
Motor to Start Aborted due to Bowed Rotor Overspeed

1. Possible Causes

POWER PLANT-DEMOUNTABLE, ENG 1 [4020KM1]
POWER PLANT-DEMOUNTABLE, ENG 2 [4020KM2]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 71-00-00-860-814	Shutdown of the Engine
AMM 71-00-00-860-823	Start the Engine (Normal Automatic Start)
AMM 71-00-51-000-802	Removal of the Power Plant (Bootstrap Method)
AMM 71-00-51-400-802	Installation of the Power Plant (Bootstrap Method)
AMM 72-35-00-290-803	Bowed Rotor Special Borescope of Inspection the High Pressure Compressor (HPC) Assembly
AMM 78-36-00-010-802	Opening of the Thrust Reverser Cowl-Doors
AMM 78-36-00-410-802	Closing of the Thrust Reverser Cowl-Doors

3. Fault Confirmation
Subtask 71-00-00-710-146-A ** ON A/C NOT FOR ALL

A. Not Applicable

NOTE: The Electronic Engine Control (EEC) channel A and channel B has detected that a specific N2 speed limit was exceeded after the engine bowed rotor start (slow motoring) sequence was enabled.

4. Fault Isolation

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS WARNING, INJURY CAN OCCUR.

WARNING: REFER TO THE MSDS FOR ALL MATERIAL USED AND THE MANUFACTURER'S SAFETY INSTRUCTIONS FOR ALL EQUIPMENT USED. IF YOU DO NOT OBEY THIS WARNING, INJURY CAN OCCUR.

CAUTION: MAKE SURE YOU REMOVE ELECTRICAL POWER FROM THE EEC BEFORE YOU REMOVE THE ELECTRICAL CONNECTORS. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE EEC CAN OCCUR.

CAUTION: YOU MUST DO ALL THE TROUBLESHOOTING STEPS IN THE SEQUENCE GIVEN. IF YOU DO NOT OBEY THE SEQUENCE, DAMAGE TO THE ENGINE CAN OCCUR.

CAUTION: BEFORE YOU OPERATE THE ENGINE, YOU MUST COLLECT THIS DATA:

BORESCOPE INSPECTION DATA
DATA STORAGE UNIT DATA
SAR/DAR DATA.

THEN YOU MUST SEND THIS DATA TO PRATT&WHITNEY FOR ANALYSIS. IF YOU DO NOT OBEY THESE INSTRUCTIONS, DAMAGE TO THE ENGINE CAN OCCUR.

CAUTION: MAKE SURE THAT YOU DO THE TROUBLESHOOTING STEPS IN THE GIVEN SEQUENCE. THIS SEQUENCE IS ALSO MANDATORY WHEN MORE THAN 24 HOURS ARE NECESSARY TO DO THE TROUBLESHOOTING PROCEDURE FOR THIS MAINTENANCE MESSAGE. IF YOU DO NOT DO THE STEPS IN THIS SEQUENCE, DAMAGE TO THE ENGINE CAN OCCUR.

Subtask 71-00-00-810-155-A ** ON A/C NOT FOR ALL

A. Do the steps that follow:
(1) Open the thrust reverser cowl-doors AMM 78-36-00-010-802.
(2) Do a borescope of the engine after a bowed rotor start AMM 72-35-00-290-803.
(3) Collect information from the bowed rotor event using one of the following tools:

Perform an EEC fault dump, collect NVM data or collect SAR/DAR data.

(4) Contact Pratt & Whitney to analyze and disposition the engine data that was collected.
(5) If it is determined that the engine is not OK:
(a) Replace POWER PLANT-DEMOUNTABLE, ENG 1 [4020KM1] or POWER PLANT-DEMOUNTABLE, ENG 2 [4020KM2] AMM 71-00-51-000-802 and AMM 71-00-51-400-802.
(6) If it is determined that the engine is OK:
(a) Do the test given in Para. 4.B.

Subtask 71-00-00-710-147-A ** ON A/C NOT FOR ALL

B. Repair Confirmation
(1) Do an engine automatic start and run the engine to idle AMM 71-00-00-860-823.

NOTE: You must start the engine using the auto start procedure. If you start the engine using manual start, the fault will not be

set.
(2) Shutdown the engine AMM 71-00-00-860-814.
(3) Check on ground scan report to confirm repair of this fault.

5. Close-up
Subtask 71-00-00-860-102-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.
(a) Close the thrust reverser cowl-doors AMM 78-36-00-410-802.

[Rev.8 from Aug 2018] 2026.04.04 04:35:07 UTC