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PRATT & WHITNEY CANADA
SERVICE BULLETIN
P&WC S.B. No. 28280
TURBOSHAFT ENGINE
COMPRESSOR DISC INSPECTION OF AND RETAINING NUT REPLACEMENT
F. Tooling -Price and Availability
Est. Price Tool No. Nomenclature ($US,) Delivery
PWC65288 CT Disc Nut Socket TBD Available
3. Accomplishment Instructions
A. Carry out a power assurance check (PAC) in accordance with the approved Rotorcraft Flight Manual prior to proceeding wih the SB. In the case of a spare engine, review latest PAC data available. If the engine has less than 10 degrees of margin, do not start disassembly. Fill in as much information as possible on attached form and fax or e-mail it to P&WC as indicated.
NOTE: This is a limited workscope SB. If hot section deterioration is observed, Maintenance Manual Borescope limits may be used to determine serviceability providing engine passes power assurance check before and after application of SB.
B. Disassemble the engine to the point necessary to remove the Power Turbine disc-shaft assembly per the applicable maintenance manual instructions.
NOTE: In order to carry out this inspection, it is necessary to remove the Fuel Control (FCU or FMM) and the Fuel heater (if equipped) .
C. Prior to removing the Power Turbine disc-shaft assembly, index the Power Turbine disc-shaft assembly per the following instructions in order to maintain its pre-disassembly dynamic balance:
(1)
Rotate the PT disk aligning the ‘‘V’’ mark of the disk at the 12 o’clock position. Mark the PT blade located at the 12 o’clock position with an approved marker.
(2)
Remove the oil transfer tube and mark the 12 o’clock position on the input gear.
CAUTION: MAKE SURE THAT YOU DO NOT MARK THE LOCKING RING
(3)
Remove the PT nut and PT shaft assembly per the MM.
(4)
Immediately transfer the mark from the PT blade to the tapered end of the PT Shaft.
D. Inspect the CT Disc by using a good light source to visually inspect the inner bore of the CT Disc for any signs of damage. Examine Area x (Ref. Dia. Z) for local surface damage. Using the criteria outlined in MM CT Disk Assembly (Assembled) -Inspection, replace the CT disk assembly if there is damage on area x (Ref. Fig. 1).
E. Remove the existing CT retaining nut following the applicable PW200 MM instructions.
P&WC Proprietary Information. Subject to the restrictions on the back of the locator.
Apr 28/2006 PW200-72-28280
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PRATT & WHITNEY CANADA
SERVICE BULLETIN
P&WC S.B. No. 28280
TURBOSHAFT ENGINE
COMPRESSOR DISC INSPECTION OF AND RETAINING NUT REPLACEMENT
3. Accomplishment Instructions (Cont’d)
F. Re-inspect the CT Disc per step D.
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