General Visual Inspection of the Total-Pressure Probe Assembly (131-9(A))

TASK 49-51-19-200-801-A
General Visual Inspection of the Total-Pressure Probe Assembly (131-9(A))

WARNING: DO NOT TOUCH THE APU UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS WHEN YOU DO THE MAINTENANCE TASK(S).

WARNING: MAKE SURE THAT THE CORRECT FIRE FIGHTING/EXTINGUISHING EQUIPMENT AND THE APPROVED PERSONNEL ARE AVAILABLE. THE APU FIRE EXTINGUISHING SYSTEM IS NOT SUFFICIENT TO EXTINGUISH A FIRE IF ACCESS DOORS 315AL AND 316AR ARE OPEN OR REMOVED.

WARNING: LOCK THE MECHANISM OF THE ACCESS DOOR 316AR WITH THE PIP PIN WHEN YOU OPEN THE ACCESS DOOR. THIS WILL PREVENT INJURY.

WARNING: BEFORE YOU START WORK, YOU MUST PUT ON A SAFETY HARNESS AND ATTACH IT TO THE ACCESS PLATFORM. WITHOUT A SAFETY HARNESS, YOU CAN FALL. THIS CAN KILL YOU OR CAUSE YOU INJURY.

CAUTION: BEFORE YOU DO THESE PROCEDURES, MAKE SURE THAT THE ENVIRONMENT IS CLEAN. IF IT IS NOT CLEAN, DAMAGE TO MECHANICAL COMPONENTS CAN OCCUR.

ZONE: 315
ZONE: 316

1. Reason for the Job
To do a check of the total-pressure probe assembly.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 4M (13 FT)
No specific	1	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
315	TAIL CONE APU AND ACCESSORY COMPARTMENT
316	TAIL CONE APU AND ACCESSORY COMPARTMENT
315AL, 316AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 24-42-00-862-001-A	De-energize the Ground Service Network Supplied from the External Power
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 49-51-19-000-003-A	Removal of the Probe - Total Pressure (131-9(A))
TASK 49-51-19-400-003-A	Installation of the Probe - Total Pressure (131-9(A))
TASK 52-41-00-010-001-A	Open the APU Doors for Access
TASK 52-41-00-410-001-A	Close the APU Doors after Access
GVI of the Total-Pressure Probe Assembly

3. Job Set-up
Subtask 49-51-19-860-057-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).
(2) On panel 25VU, make sure that the APU MASTER SW pushbutton switch is in the OFF position.
(3) Put a WARNING NOTICE(S) in position on panel 25VU to tell persons not to start the APU.
(4) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).

Subtask 49-51-19-865-062-A ** ON A/C NOT FOR ALL

B. Open, safety and tag these circuit breakers in this sequence:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41

Subtask 49-51-19-010-056-A ** ON A/C NOT FOR ALL

C. Get Access
(1) Put an ACCESS PLATFORM 4M (13 FT) in position below APU access doors 315AL and 316AR.
(2) Open APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-010-001).
(3) Set the light switch 11LJ to the ON position.

4. Procedure
Subtask 49-51-19-210-050-A ** ON A/C NOT FOR ALL

A. General Visual Inspection (GVI) of the Total-Pressure Probe Assembly
(1) Do a GVI of the total-pressure probe assembly for damage or discontinuities:
(a) Make sure that there are no dents or cracks on the total-pressure probe assembly.

NOTE: Dents and cracks are not permitted.

(b) Do a visual check for fretting on the total-pressure probe assembly.

NOTE: The maximum permitted depth of the fretting damage is 0.005 inch (0.13 mm).

NOTE: Blockages and elongations are not permitted.

(d) Make sure that there is no loose insert and no distortion in the total-pressure probe assembly.

NOTE: Loose inserts or distortions are not permitted.

(2) If the total-pressure probe assembly is not in the correct condition, replace it (Ref. AMM TASK 49-51-19-000-003) and (Ref. AMM TASK 49-51-19-400-003).

5. Close-up
Subtask 49-51-19-410-053-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Set the light switch 11LJ to the OFF position.
(3) Close APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-410-001).
(4) Remove the access platform(s).

Subtask 49-51-19-865-063-A ** ON A/C NOT FOR ALL

B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41

Subtask 49-51-19-860-058-A ** ON A/C NOT FOR ALL

C. Put the aircraft back to its initial configuration.
(1) Put the related hydraulic system in the pressurized configuration (Ref. AMM TASK 29-00-00-864-001).
(2) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).
(3) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 01:31:07 UTC