Preliminary Requirements

Procedure

1. SUBTASK 72-31-11-350-073 Remove the Chocking Pads from the LPC Rotor Blade Assembly

   1. Remove the bulk of the chocking pad.

      1. Use hand methods.

      2. Take extreme care not to cause damage to the fan blade.

   2. Discard assembly A type chocking pads.

2. SUBTASK 72-31-11-350-051 Remove the Remaining Adhesive from the Chocking Pads, Assembly B

   1. Remove the remaining adhesive.

      1. Use hand methods.

         1. Take extreme care not to cause damage to the chocking pad.

3. SUBTASK 72-31-11-220-111 Examine the Front and Rear Chocking Pads, Assembly B

   1. Examine the front chocking pad.

      1. Reject if cracked or sharp cornered

      2. The thickness of chocking pad must be between 0.486 in. (12.32 mm) and 0.513 in. (13.05 mm).

   2. Examine the rear chocking pads.

      1. Reject if cracked or sharp cornered.

      2. The thickness of chocking pad must be between 0.295 in. (7.47 mm) and 0.318 in. (8.08 mm).

4. SUBTASK 72-31-11-110-066 Remove the Remaining Adhesive from the Bottom of the Blade Root

   1. Remove the remaining adhesive.

      1. Refer to TASK 72-31-11-100-000 (CLEANING-000).

      2. Use non-metallic scraper.

5. SUBTASK 72-31-11-230-061 Examine the Fan Blade Assembly for Cracks

   1. 
      CAUTION
      FOLLOWING THE CRACK TEST PROCEDURE ENSURE THAT FLUORESCENT PENETRANT IS THOROUGHLY REMOVED FROM THE FAN BLADE ROOT COATING.

      Fluorescent penetrant examine the blade root.

      1. Cracks are not permitted.

      2. Refer to TASK 72-31-11-200-000 (INSPECTION/CHECK-000).

      3. Use Fluorescent Penetrant Inspection Equipment.

6. SUBTASK 72-31-11-110-067-001 Prepare the LPC Rotor Blade for Bonding

   1. 

      CAUTION

      DO NOT APPLY ABRASIVE BLAST ON POST SB 72-0375 AND POST SB 72-0384 (METCO 58 COATED ROOT) FAN BLADES AS THIS COULD DAMAGE THE INTEGRITY OF THE COATING.

      NOTE

      This SUBTASK is applicable to the chocking pad (Assembly A).

      Refer to Figure

   2. Swab degrease the bonding areas.

      1. Refer to the SPM TASK 70-11-26-300-503.

      2. Use CoMat 01-031 ACETONE (CH3)2CO or CoMat 01-124 ISOPROPYL ALCOHOL.

   3. Hand clean the bonding surface of the rotor blade (Area AE).

      1. Use CoMat 05-017 GARNET PAPER, 60 GRIT or CoMat 05-016 GARNET PAPER, 80-GRIT.

   4. Do step A. again.

   5. Do a water break test to make sure that the bonding surfaces are clean.

      1. Refer to the SPM TASK 70-36-02-360-501.

   6. Remove the break test fluid by swabbing.

      1. Refer to the SPM TASK 70-36-02-360-501.

7. SUBTASK 72-31-11-110-067-002 Prepare the LPC Rotor Blade for Bonding

   1. NOTE

      This SUBTASK is applicable to the chocking pad (Assembly B).

      Refer to: Figure

   2. Locally swab degrease the bonding area.

      1. Refer to the SPM TASK 70-11-26-300-503.

   3. Abrade bond areas with scotchbrite soaked in solvent (Area AE).

      1. Use CoMat 05-126 ABRASIVE PAD, ALUMINUM OXIDE, VERY FINE scotchbrite.

         1. Use CoMat 01-438 SOLVENT, CoMat 01-031 ACETONE (CH3)2CO or CoMat 01-060 ACETONE (CH3)2CO.

   4. Swab degrease the bonding area and allow to evaporate.

      1. Refer to the SPM TASK 70-11-26-300-503.

8. SUBTASK 72-31-11-360-058-001 Prepare the Chocking Pad for Bonding

   1. NOTE

      This SUBTASK is applicable to the chocking pad (Assembly A).

      Swab degrease the bonding surfaces.

      1. Refer to the SPM TASK 70-11-26-300-503.

   2. Hand clean the bonding surfaces of the chocking pads.

      1. Refer to the SPM TASK 70-36-02-360-501.

   3. Do step A. again.

   4. Do a water break test to make sure that the bonding surfaces are clean.

      1. Refer to the SPM TASK 70-36-02-360-501.

   5. Remove the break test fluid by swabbing.

      1. Refer to the SPM TASK 70-36-02-360-501.

9. SUBTASK 72-31-11-360-058-002 Prepare the Chocking Pad for Bonding

   1. NOTE

      This SUBTASK is applicable to the chocking pad (Assembly B).

      NOTE

      If the chocking pad is replaced by a new one, this SUBTASK need not be done.

      Refer to Figure.

   2. Swab degrease the surface E of the chocking pad.

      1. Refer to the SPM TASK 70-11-26-300-503.

   3. 
      CAUTION
      DO NOT TOUCH THE BACKING PAPER OF THE DOUBLE SIDED ADHESIVE TAPE UNTIL IT IS ATTACHED TO THE FAN BLADE.

      Apply the double sided adhesive tape to surface E. No Air bubbles, creases or wrinkles are permitted.

      1. Use CoMat 02-271 ADHESIVE TAPE (DOUBLE SIDED).

   4. The adhesive tape on the pad is to be trimmed flush. It is permissible to stick out within 0.04in. (1.0 mm) all round.

10. SUBTASK 72-31-11-360-059-001 Apply and Cure the Cold Curing Silicone Rubber Compounds

    1. 

       CAUTION

       YOU MUST NOT EAT ANYTHING OR SMOKE AT LOCATIONS WHERE THESE MATERIALS ARE USED.

       NOTE

       This SUBTASK is applicable to the chocking pad (Assembly A).

       Refer to Figure and Figure

    2. Apply a thin layer of primer to each of the prepared mating surfaces of the blade and the chocking pads. Dry in air for 30 minutes.

       1. Use CoMat 08-014 PRIMER, SILICONE ADHESIVE/SEALANT.

       2. Refer to the SPM TASK 70-36-02-360-501.

    3. Apply the cold curing silicone compound to each of the mating surfaces of the fan blade and the chocking pads.

       1. Use CoMat 08-013 COLD CURING SILICONE COMPOUND.

       2. Use a corrugated scraper.

       3. Refer to the SPM TASK 70-36-02-360-501.

    4. Assemble the front and the rear chocking pads to the fan blade immediately.

       1. Use CoMat 02-001 ADHESIVE TAPE (MASKING) to hold the chocking pads in position.

    5. NOTE

       The parts can be touched after 12 hours.

       Cure the compound at 68 deg F (20 deg C) for 48 hours. Do not apply a load during this time.

11. SUBTASK 72-31-11-360-059-002 Apply the Chocking Pad to the Fan Blade

    1. 

       CAUTION

       DO NOT TOUCH ADHESIVE TAPE.

       NOTE

       This SUBTASK is applicable to the chocking pad (Assembly B).

       Refer to Figure and Figure.

    2. Remove the backing paper from the chocking pad.

    3. Put the pad on the plade root.

    4. NOTE

       Once in position the pad cannot be moved or its position adjusted.

       Apply light hand pressure for 1 minute.

    5. Lightly twist the pad to ensure full adhesion to blade and backing plate.

12. SUBTASK 72-31-11-220-088 Examine the Repaired Area of the Fan Blade Assembly

    1. Refer to Figure and Figure.

    2. Visually and dimensionally examine the fan blade assembly.

13. SUBTASK 72-31-11-350-074 Make a Mark on the Fan Blade

    1. Write VRS1022 adjacent to the part number.

       1. Use a Vibrating Marking Pencil.

Figure: Replace the front and rear chocking pads

Replace the front and rear chocking pads



Figure: Replace the front and rear chocking pads

Replace the front and rear chocking pads



Figure: Replace the front and rear chocking pads - assembly A

Replace the front and rear chocking pads - assembly A



Figure: Replace the front and rear chocking pads - assembly B

Replace the front and rear chocking pads - assembly B