(2)
Remove and discard packing. NOTE : MAKE SURE THE APU INTERNAL TEMPERATURE IS NOT MORE THAN 176F
____ (80C) BEFORE THE BORESCOPE IS PUT INTO THE APU. HEAT CAN DAMAGE THE BORESCOPE.
(3)
Push the optic fiber through dedicated boroscope port on scroll, proceed past the trailing edge of the diffuser and examine the load compressor diffuser vanes.
(4)
The load compressor diffuser vanes should be checked for impact damage. (Ref. Fig. 602/TASK 49-20-00-991-016)
(a)
The following observations are acceptable:
(b)
The following observations are not acceptable, the observations are criteria for APU removal:
1_ Leading edge nicks and rough edges due to erosion are
acceptable without significantly displaced material (1).
2_ Discoloration of vanes are acceptable.
3_ Cracks found in the braze fillet area is acceptable (2).
1 Bucket shaped erosion is not acceptable (3).
_ Subtask 49-20-00-960-054
B. Examine the load compressor impeller trailing edge for damage.
(1) Prepare to turn rotating group to examine the load compressor impeller.
(a) Remove cap on end of starter.
R EFF : 001-049, 101-105, 107-107, 151-199, 49-20-00Page 604 201-210, Config-3 Aug 01/05
CES
Boroscope Examination
Figure 601/TASK 49-20-00-991-015
CES
Load-Compressor Diffuser Damage-Criteria
Figure 602/TASK 49-20-00-991-016
CES
(b) Insert a 0.25 inch hex socket, with attached 6 inch extension and ratchet wrench, onto the 1/4 inch hex shaft on the end of the starter.
NOTE : MAKE SURE THE APU INTERNAL TEMPERATURE IS NOT MORE THAN
____ 176F (80C) BEFORE THE BORESCOPE IS PUT INTO THE APU. HEAT CAN DAMAGE THE BORESCOPE
NOTE : MAKE SURE THE BORESCOPE CLEARS THE COMPRESSOR IMPELLER
____ BLADES BEFORE THE APU IS ROTATED. ROTATION OF THE APU ROTATING GROUP CAN DAMAGE THE BORESCOPE.
(2)
Push the optic fiber through dedicated boroscope port on scroll, proceed between two load compressor diffuser vanes, to view the edge of the impeller blades.
(3)
Turn the rotating group as necessary and examine the load compressor impeller trailing edges. (Ref. Fig. 603/TASK 49-20-00-991-017)
(4)
The following observations are acceptable:
(a)
Rough edges due to erosion or nicks without significantly
displaced material is acceptable (4).
(b)
Discoloration of the blade is acceptable.
(c)
Indications of impeller to shroud incursions (rubs) are
acceptable
(d)
Accumulation of shroud abradable material on blade is acceptable (5).
(5)
The following observations are not acceptable, the observations are criteria for APU removal:
(a) Remove the APU if visible cracks of the trailing edge, shroud line, hub are observed (7) or visible pieces are missing (6).
(6)
Remove optic fiber borescope from the load compressor borescope port.
(7)
Lubricate new packing with Lubricating Oil (MIL-L-6081, Grade 1005 or 1010 and install on plug.
(8)
Install plug on load compressor borescope port.
(9)
TORQUE the plug to 0.9 m.daN (79.64 lbf.in)
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CES
Load-Compressor Trailing-Edge Damage Criteria
Figure 603/TASK 49-20-00-991-017
CES
(10)
Safety the plug with MISCELLANEOUS (Material No. 19-018) Subtask 49-20-00-960-055
C.
Examine the Inlet Guide Vanes for damage.
(Ref. Fig. 604/TASK 49-20-00-991-018)
(1)
Loosen bolts that hold cover plate and rotate cover plate clockwise to access clevis assembly.
(2)
Remove the bolt that holds the inlet guide vane actuator (IGVA) and clevis assemblies together (Ref. TASK 49-23-51-000-004).
(3)
Pull inlet guide vane linkage, by hand, into the engine assembly until the linkage stops and the inlet guide vanes are fully closed.
(4)
Put the optic fiber borescope through the compressor inlet duct and perforated inlet housing to the inlet guide vanes.
(5)
Examine the guide vanes for evidence of damage.
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