Borescope Inspection of NF Speed Probe [PW11]

TASK 77-11-22-290-801-A
Borescope Inspection of NF Speed Probe

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 INSTRUCTION, INJURY CAN OCCUR.

WARNING: DO THE BORESCOPE INSPECTION IN AN AREA WHICH HAS PROTECTION FROM THE WEATHER. IF A BORESCOPE INSPECTION IS DONE IN WET CONDITIONS, USE SUFFICIENT PROTECTION TO PREVENT POSSIBLE ELECTRICAL SHOCK TO THE OPERATOR OR DAMAGE TO THE EQUIPMENT. AN ELECTRICAL SHOCK CAN KILL A PERSON OR CAUSE A BAD INJURY.

CAUTION: MAKE SURE THAT THE TEMPERATURE IN THE ENGINE IS LESS THAN 150 DEG.F (65.6 DEG.C) BEFORE YOU INSTALL THE BORESCOPE TOOL(S) IN THE ENGINE. IF THE ENGINE IS HOTTER THAN 150 DEG.F (65.6 DEG.C), THE BORESCOPE TOOL(S) CAN MELT AND BECOME DAMAGED.

1. Reason for the Job
Use this procedure to do an inspection of the NF speed probe after a bird ingestion, surge with a Pb more than 350 psi (2414 kPa), or a bird ingestion that occurs with an engine surge or stall identified by AMM TASK 72-00-00-210-807 or AMM TASK 72-00-00-200-809.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 1M(3 FT)
No specific	1	THERMOMETER - METAL PROBE TYPE, 0 TO 400 DEG.F
CTE8003	1	SYSTEM BOROSCOPE (VIDEO)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL, 438AR, 452AR
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL, 448AR, 462AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-00-00-860-832-A	Procedure to Prevent Engine Motoring and to Stop the Electrical Supply to the EEC
TASK 71-13-00-010-802-A	Opening of the Fan Cowl Doors
TASK 77-11-22-000-801-A	Removal of the NF Speed Probe
TASK 77-11-22-210-801-A	Visual Inspection of NF Speed Probe
TASK 77-11-22-400-801-A	Installation of the NF Speed Probe
TASK 78-30-00-040-805-A	Deactivation of the Thrust Reverser System for Ground Maintenance
TASK 78-36-00-010-802-A	Opening of the Thrust Reverser Cowl-Doors
NF Speed Probe Area

3. Job Set-up
Subtask 77-11-22-941-053-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) Do the procedure to prevent engine motoring and to stop the electrical supply to the Electronic Engine Control (EEC)
(Ref. AMM TASK 71-00-00-860-832).

Subtask 77-11-22-010-056-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL 448AR
(2) Put an ACCESS PLATFORM 1M(3 FT) in position.

Subtask 77-11-22-040-053-A ** ON A/C NOT FOR ALL

C. Deactivation of the Thrust Reverser for Maintenance

WARNING: YOU MUST DEACTIVATE THE THRUST REVERSER BEFORE YOU DO WORK ON OR AROUND IT. IF YOU DO NOT, THE THRUST REVERSER CAN OPERATE ACCIDENTALLY AND CAUSE AN INJURY AND/OR DAMAGE.

(1) Do the deactivation of the thrust reverser system for maintenance (Ref. AMM TASK 78-30-00-040-805).

Subtask 77-11-22-010-057-A ** ON A/C NOT FOR ALL

D. Get Access
(1) Open the right thrust-reverser cowl-doors (Ref. AMM TASK 78-36-00-010-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
452AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
462AR

4. Procedure

CAUTION: WIPE CLEAN ALL PARTS AND TOOLS AS NECESSARY TO REMOVE UNWANTED DEBRIS AND PREVENT DAMAGE TO THE ENGINE.

Subtask 77-11-22-290-050-A ** ON A/C NOT FOR ALL

A. Do the Borescope Inspection of the NF Speed Probe
(1) If the engine was in operation a short time before this inspection, do a temperature check in the fan area with the THERMOMETER - METAL PROBE TYPE, 0 TO 400 DEG.F.
(a) Wait three to five hours after engine shutdown to do a borescope inspection, if necessary.
(2) Remove the NF speed probe (Ref. AMM TASK 77-11-22-000-801).
(a) If there is damage to the NF sensor, you must do a borescope inspection of the fan shaft and fasteners (Ref. AMM TASK 77-11-22-210-801).
(3) Do a borescope inspection of the NF speed probe area with the CTE8003 SYSTEM BOROSCOPE (VIDEO) as follows:

NF Speed Probe Area ** ON A/C NOT FOR ALL

WARNING: BE CAREFUL TO EXAMINE THE POWER CABLE OF THE LIGHT SOURCE BEFORE YOU USE IT. DO NOT USE THE CABLE IF THE INSULATION HAS CUTS OR WORN OR BROKEN AREAS. INSULATION WITH THIS TYPE OF DAMAGE IS DANGEROUS BECAUSE OF POSSIBLE ELECTRICAL SHOCK TO THE OPERATOR.

(a) Put the CTE8003 SYSTEM BOROSCOPE (VIDEO) probe in the opening that the NF speed probe installs into.
(b) Turn the fan

CAUTION: MAKE SURE THAT YOU ARE ON THE FRONT SIDE OF THE FAN SHAFT WHEN YOU TURN IT COUNTERCLOCKWISE. IF YOU DO NOT OBEY THIS PRECAUTION, DAMAGE TO THE INTERNAL BRUSH SEALS CAN OCCUR.

1 Turn the fan to turn the shaft.
(4) If there is light contact on the sensor, do an inspection check for shaft damage and loose fasteners. See the figure and refer to Table 601 for damage limits.
(a) Do the borescope inspection again for each 3 000 cycles until the shaft is replaced.
(b) Remove the shaft and examine at next major interval.
(5) If there is heavy contact on the housing, do an inspection check for shaft damage and loose fasteners. See the figure and refer to Table 601 for damage limits.
(a) To examine the bolt preload, remove the borescope, apply light pressure and do a check for looseness.
(b) Remove and examine the shaft and sensor bolt in 750 cycles.

Table 601: Borescope Inspection/Limits for the NF Speed Probe Area

EXAMINE	DAMAGE	DISPOSITION
Area A	Less than 0.003 in. (0.08 mm) depth	Permitted.
	0.003 in. (0.08 mm) to 0.015 in. (0.38 mm) depth	Not permitted, blend repair or replace in ten flights.
	More than 0.015 in. (0.38 mm) depth	Contact P&W.
Area B	Less than 0.010 in. (0.25 mm) depth	Permitted.
	0.010 in. (0.25 mm) to 0.020 in. (0.51 mm) depth	Not permitted, replace in 750 hours.
Bolt head	Less than 0.010 in. (0.25 mm) depth	Permitted.
	0.010 in. (0.25 mm) to 0.020 in. (0.51 mm) depth	Not permitted, replace in 750 hours.
Bolt preload	Bolt head moves radially when you apply less than 5 lb (2.27 kg) of load	Not permitted, replace in 750 hours.
	Bolt head moves axially when you apply less than 5 lb (2.27 kg) of load	Not permitted. If the rotor turns freely replace in ten flights. If rotor does not turn freely, it must be replaced.

(6) Install the NF speed probe (Ref. AMM TASK 77-11-22-400-801).
(7) Examine the assembly for foreign objects, damage and correct assembly.

[Rev.10 from 2021] 2026.04.01 13:10:42 UTC