3. Job Set-up
__________ Subtask 49-20-00-865-050
A. 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 49-20-00-010-050
B. Get Access
(1)
Put the access platform in position below the APU access doors 315AL and 316AR.
(2)
Open the APU access doors 315AL, 316AR (Ref. TASK 52-41-00-010-001).
(3)
Make sure that the light control SW 11LJ is set to the ON position.
4. Procedure
_________
(Ref. Fig. 601/TASK 49-20-00-991-001, 602/TASK 49-20-00-991-002)
NOTE : You should communicate with the local Garrett Field Service
____
Representative, if you are not sure of any unusual wear or
deterioration that is apparent during the borescope inspection.
Subtask 49-20-00-290-056
A. Borescope Inspection of the Load-Compressor and Engine-Compressor Section
(1)
Remove the access cover plate on the compressor inlet duct.
(2)
Remove the IGV-Actuator (Ref. TASK 49-23-51-000-002).
(3)
Assemble the boroscope 6/8/mm to the light source, Olympus 1LK-2.
(4)
Put the borescope through the air intake access hole and make an inspection of the IGVs for this damage:
(a) Examine inlet guide vanes for evidence of FOD. Bent or missing vanes are not permitted.
Auxiliary Power Unit - Borescope Inspection
Figure 601/TASK 49-20-00-991-001
CES
Thermocouple-Rake Attachment Positions
Figure 602/TASK 49-20-00-991-002
CES
(5)
Before you do a borescope inspection of the parts of the engine that turn, you must remove the cover plate from the starter motor (8KA). This will allow access to the starter motor shaft. Do these steps:
(a)
Remove the screws which attach the cover plate to the forward face of the starter motor (8KA).
(b)
Remove the cover plate from the forward face of the starter motor.
(6)
Install the socket spanner on the extension of the starter motor shaft. Turn the socket spanner counterclockwise to turn the engine.
(7)
Put the borescope through the inlet guide vanes and make an inspection of the load compressor for this damage:
(a)
Remove the APU, if any large blade pieces (25% or greater of total blade) - of the leading edge
or
- of the trailing edge
are missing.
(b)
Bent inducer blade tips are acceptable provided that the bend does not exceed 25% of the blade span.
(8)
Make an inspection of the engine compressor for this damage:
(a)
Remove the APU, if any large (25% or greater of total blade) main or splitter blade pieces (leading or trailing edge) are missing.
(b)
Bent inducer blade tips are acceptable provided that the bend does not exceed 25% of the blade span.
(9)
Remove the borescope.
(10) Replace the access cover plate to the compressor air inlet duct.
Subtask 49-20-00-290-057
B. Borescope Inspection of the Power Section
(1)
Remove the igniter plug (8031KM) to get access to the combustion chamber (Ref. TASK 49-41-41-000-001).
(2)
Assemble the GUIDE TOOL - BORESCOPE, APU and install it in position at the igniter hole.
(3)
Put the borescope through the igniter plug hole and make an inspection of the combustion chamber for this damage:
(a)
Hot spots with severe oxidation or erosion that causes a loss of material, such as widened cracks or holes are not permitted.
(b)
Examine the fuel-nozzle shrouds for severe cracks, distortion or burn-through. If damaged, remove and replace with serviceable fuel nozzle shroud.
(4)
Make an inspection of the turbine rotor and turbine nozzles for this damage:
(a) Turbine Rotor
1 Any seperated blades are not permitted.
_
2 Inducer tip corrosion is permitted.
_
(b) Turbine Nozzles 1 Thru wall holes in vane leading edges are not permitted.
_ 2 Broken vanes or large missing pieces of vane edges (25% or
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