SERVICE BULLETIN ENGINE - INSPECTION OF THE LOW -PRESSURE -TURBINE FORWARD -SHAFT AIR -COOLING HOLE

Transcription

1 SERVICE BULLETIN ENGINE - INSPECTION OF THE LOW -PRESSURE -TURBINE FORWARD -SHAFT AIR -COOLING HOLE 1. PLANNING INFORMATION A. Effectivity (1) Engines All AE 3007A, A1/1, A1/3, A1, A1P, A1E and A2 engines. All AE 3007C, C1, and C2 engines. (2) Spares All low--pressure--turbine forward shafts with part numbers , , , , and B. Reason Rolls--Royce has found incorrect edge breaks on the inner diameter of the low--pressure-- turbine (LPT) forward--shaft air--cooling holes. The incorrect edge breaks are a result of a hand edge break procedure, which has been replaced by an automated procedure in the hole drilling process. C. Description This service bulletin gives you the procedure to inspect the inner diameter of the mid--span and aft LPT forward--shaft air--cooling holes to make sure that there are no sharp edges. If an incorrect edge break is identified, then this service bulletin also gives you the procedure to repair the LPT forward--shaft air--cooling holes. D. Approval Technical aspects are FAA approved. E. Manpower In Service -- Not applicable. Engine Removed Inspection without repair: Approximately 1.0 man--hour is necessary to do this service bulletin. Inspection with repair: Approximately 2.0 man--hours are necessary to do this service bulletin. F. Compliance Recommended. Do this bulletin when the engine is removed from the aircraft and the LPT forward--shaft is exposed. You do not need to disassemble the engine more than required for the scheduled or unscheduled maintenance. A spare/replacement LPT forward--shaft should be inspected (and repaired if necessary) before installation. G. Interchangeability -- Not affected H. Material Availability -- Not affected Page1of6

2 I. Tooling -- (1) Videoscope (borescope), Olympus 4mm direct and side view (IPLEX FX Model IV8420, or IPLEX LX Model IV8420L1, or IPLEX LT Model IV8420L2, or equivalent) -- Optional. J. Weight and Balance -- Not affected K. Electrical Load Data -- Not affected L. References (1) AE 3007A, C Series Engine Manual (EM), CSP (2) AE--Series Standard Practices Manual (SPM), CSP M. Prerequisites -- None N. Corequisites -- None 2. ACCOMPLISHMENT INSTRUCTIONS A. Do the inspection of the inner diameter of the mid--span and aft low--pressure--turbine (LPT) forward--shaft (shaft) air--cooling holes (air hole) to verify the presence of an edge break around the entire circumference of each air hole. NOTE: The inspection of the inner diameter air hole edge break can be accomplished with a borescope inserted in the LPT shaft. The mid--span air hole edge break can also be viewed through the air hole on the opposite side of the LPT shaft with a light. REF. FIG. 1 (1) If you can see high metal, then go to step 2.B to repair the LPT shaft air holes. (2) If an edge break around the entire circumference of the air hole cannot be seen, then go to step 2.B to repair the LPT shaft. (3) If you cannot see an edge break around the entire circumference of the LPT shaft air hole, then speak with Rolls--Royce Corporation for additional instructions. (4) If you cannot see high metal and each LPT shaft air hole has the required edge break around the entire circumference of the air hole, then go to step 2.D. B. Repair the LPT shaft air holes. (1) Blend the part to remove the high metal or the sharp edges on the inner diameter of the LPT shaft air holes (Ref. TASK , SPM). (a) For the mid--span shaft air holes, do not exceed the maximum hole size of in. (12.95 mm). (b) For the aft LPT shaft air holes, do not exceed the maximum hole size of in. (11.38 mm). C. Do the inspection of the LPT shaft air holes. REF. FIG. 2 (1) If the LPT shaft is not at the piece--part level, then do the spot fluorescent penetrant inspection (FPI) of the LPT shaft with method C, sensitivity level 4 (Ref. TASK , SPM) to the limits that follow. (2) If the LPT shaft is at the piece--part level and the coating has been removed, then do the magnetic particle inspection (Ref. TASK , SPM) of the LPT shaft to the limits that follow. Page2of6

3 ITEM SERVICEABLE LIMITS REPAIR LIMITS ACTION NECESSARY Air holes --Indications None permitted. Not repairable. Replace the LPT shaft. (3) If the spot FPI or the magnetic particle inspection show cracks or indications and the LPT shaft is not serviceable, then complete the Service Engineering Inspection Feedback Form and send to Rolls--Royce. D. Touch--up the aluminum coating on the LPT shaft. (1) If required, repair the LPT shaft aluminum coating (Ref. Rolls--Royce approved repair). E. Identify the LPT shaft. (1) Use the vibro--peen method 2D1 or 2E1 to write the applicable service bulletin number adjacent to the part number on the LPT shaft (Ref. TASK , SPM). (a) AE 3007A series engines write: SB434. (b) AE 3007C series engines write: SB336. (2) If the LPT shaft has black oxide finish, then it is not necessary to touch up the black oxide coating. F. Record compliance with this service bulletin in the applicable section of the engine logbook. Page3of6

4 Low--pressure--turbine Forward shaft Air--cooling Holes FIG. 1 Page4of6

5 Service Engineering Inspection Feedback Form FIG. 2 Page5of6

6 3. MATERIAL INFORMATION: A. Configuration Chart -- Not Applicable B. Consumable Materials -- None C. Expendable Parts -- None CUSTOMER SUPPORT ROLLS-ROYCE Page6of6