(2)
On the panel 25VU, make sure that the APU MASTER SW pushbutton switch is off.
(3)
Put a warning notice in the cockpit to tell persons not to start the APU.
(4)
Make sure that the hydraulic systems are depressurized (Ref. TASK 29-00-00-864-001).
Subtask 49-20-00-865-070
B. Open, safety and tag this(these) circuit breaker(s):
-------------------------------------------------------------------------------PANEL DESIGNATION IDENT. LOCATION -------------------------------------------------------------------------------121VU APU/APU/CTL 2KD L42 121VU APU/ECB/SPLY 1KD L41
Subtask 49-20-00-010-059
C. Get Access
(1)
Put the access platform in position below the APU access doors 315AL and 316AR.
(2)
Open the access doors 315AL and 316AR (Ref. TASK 52-41-00-010-001).
(3)
Set the LIGHT control switch 11LJ to the on position.
4. Procedure
_________
(Ref. Fig. 601/TASK 49-20-00-991-005, 602/TASK 49-20-00-991-014) Subtask 49-20-00-020-057
A. Preperation for Inspection.
(1)
Remove the cooling fan inlet duct (Ref. TASK 49-52-53-000-001),para.4. A. (6).
(2)
Remove the two igniter plugs (Ref. TASK 49-41-41-000-003).
(3)
Remove the LH thermocouple probe (Ref. TASK 49-72-15-000-001).
(4)
The borescope inspection kit is made up of the following:
-
Flexible Borescope (8mm dia.).
-
Flexible Borescope (5mm dia.).
-TOOL FOR ENDOSCOPIC INSPECTION
-Borescope Battery.
-Cable Adapter.
-Liquid Light Guide Cable.
-Eye-Piece Adapter.
-
Borescope Light Source. Subtask 49-20-00-290-059
B.
Inspection.
(1) Inspect the load compressor and the Inlet-guide-vanes (IGV).
-For Limits of damage refer to Figur 602.
(a)
Use a rigid boroscope-8mm dia.
(b)
Connect the borescope to the light source with the liquid light guide cable .
APU Power Plant - Boroscope Inspection
Figure 601/TASK 49-20-00-991-005
CES
APU Power Plant - Boroscope Inspection
Figure 602/TASK 49-20-00-991-014
CES
(c)
Insert the borescope into the front half of the air inlet plenum.
(d)
Inspect the IGV's for cracked or bended vanes, no damages are permitted.
(e)
Inspect the load compressor impeller while slowly rotating the rotor using a suitable ratchet handle, extension and socket on the cooling fan center shaft retaining nut.
(f)
If there are bent, cracked or broken blades, replace the APU. (Ref. TASK 49-11-11-000-003)
(g)
Erosion and impacts on the L/C-impeller are permitted as defined at the hatched area, blade root area dimension A (A=5mm) no impacts and cracks.
(2)
Inspect the Power Section Compressor.
-For Limits of damage refer to Figur 602.
(a)
Use a rigid boroscope-8mm dia.
(b)
Connect the borescope to the light source with the liquid light guide cable .
(c)
Insert the borescope into the rear half of the air inlet plenum.
(d)
Inspect the power compressor impeller while slowly rotating the rotor using a suitable ratchet handle, extension and socket on the cooling fan center shaft retaining nut.
(e)
If there are bent, cracked or broken blades, replace the APU. (Ref. TASK 49-11-11-000-003)
(f)
Erosion and impacts on the P/C-impeller are permitted as defined at the hatched area, blade root area dimension A (A=7mm) no impacts and cracks.
(3)
Inspect the Combustor Exhaust and Lining.
(a) Use a flexible/fibrescope borescope 5mm dia.with guide tool and borescope battery. The light source is connected to the battery with the cable adapter .
NOTE : For combustor lining inspection, the rigid borescope
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