Preliminary Requirements

Procedure

1. SUBTASK 72-32-85-350-055 Prepare Areas of Damage

   1. 
      CAUTION
      CHECK THE TOTAL REPAIR AREA PRIOR TO STARTING THE REPAIR. DO NOT CARRY OUT REPAIR BY FILLING THE ATTRITION LININGS IF THE TOTAL REPAIRED AREA EXCEEDS 20 PERCENT OF THE TOTAL FAN CASE ATTRITION LINING AREA. THESE REPAIR LIMITS MUST BE APPLIED TO THE FULL DEPTH OF THE GRC LAYER.
      
      CAUTION
      THE FAN CASE IS MADE FROM TITANIUM ALLOY AND IS THIN IN SOME AREAS. IF YOU HIT THE FAN CASE WITH A CHISEL OR SCRAPER YOU CAN MAKE IT UNSERVICEABLE.
      
      CAUTION
      YOU MUST USE THE CHISEL, SHARP BLADE OR SCRAPER IN A CIRCUMFERENTIAL DIRECTION TO PREVENT THE EDGES OF THE BLADE SCORING THE FAN CASE.
      
      CAUTION
      YOU MUST ALWAYS TRY TO POINT THE CHISEL OR SHARP BLADE PARALLEL WITH THE SURFACE OF THE FAN CASE.
      
      CAUTION
      STOP MACHINING AS SOON AS THE FILES, CUTTERS OR MACHINING BITS ARE THROUGH THE LINING MATERIAL. USE A STOP-MACHINING OR SLEEVE OR OTHER PENETRATION LIMITING DEVICE TO PREVENT DAMAGE TO THE CASING MATERIAL.
      
      CAUTION
      DO NOT USE POWERED TOOLS WITH STEEL CHISEL OR SIMILAR BITS.
      
      CAUTION
      DO NOT OPERATE WITHOUT SAFETY GOGGLES AND OTHER GUARD EQUIPMENT. FLYING PARTICLES CAN CAUSE INJURY.

      NOTE

      Remove the minimum quantity of material necessary to remove all damage.

      Remove all loose and damaged material from repair area.

      1. Use hand held pneumatic grinder and rotary files.

      2. Refer to Figure.

      3. Be carefull not to cause damage to the inner surface of the fan case assembly.

   2. NOTE

      These repair limits must be applied to the full depth of the GRC layer.

      Examine the Glass Reinforced Composite (GRC) skin and check for indications of blistering or lack of bond by pressing or tapping.

      1. Check visually and by tapping.

      2. A hollow sound is indicative of suspect bond.

      3. Remove any unsound material.

      4. If damage more than 4 sqin. (25.8 sqcm) in front attrition area, repair, refer to VRS1955 TASK 72-32-85-300-007 (REPAIR-007).

      5. Examine the repaired area ratio not more than 20 percent of total rear attrition area and/or rear attrition area of one segment of attrition lining.

      6. If more than 20 percent, repair, refer to VRS1956 TASK 72-32-85-300-008 (REPAIR-008).

   3. NOTE

      Remove the minimum quantity of material necessary to remove all damage.

      Cut away the defective area.

      1. Use hand held pneumatic grinder and rotary files.

      2. Be careful not to cause damage to the inner of the fan case assembly.

   4. Make rough the repair area.

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

   5. Remove any remaining debris.

      1. Use vacuum cleaner.

   6. Examine the fan case inner surface of the repair area.

      1. Examine the fan case inner surface. If necessary repair any nicks, dents, scratches and gouges.

      2. If necessary do repair, VRS1405 TASK 72-32-85-300-005 (REPAIR-005).

2. SUBTASK 72-32-85-110-069 Remove the Grease from the Repair Area

   1. 
      WARNING
      ALWAYS MAKE SURE THERE IS SUFFICIENT VENTILATION IN THE WORK AREA. EYE PROTECTION MUST ALWAYS BE USED. DO NOT LET THE SOLVENT CLEANER OR ITS VAPOR TOUCH THE EYES OR SKIN. PROTECTIVE CLOTHING AND FACE MASK MUST ALWAYS BE USED. ALWAYS KEEP OPEN FLAMES AWAY FROM THE WORK AREA. IT IS THE RESPONSILIBILTY OF THE OPERATOR TO OBTAIN AND OBSERVE THE MANUFACTURERS MATERIAL SAFETY SHEETS FROM THE CONSUMABLE MATERIALS INFORMATION SUCH AS HAZARDOUS INGREDIENTS, PHYSICAL/CHEMICAL CHARACTERISTICS, FIRE, EXPLOSION, REACTIVITY, HEALTH HAZARD DATA, PRECAUTIONS FOR SAFE HANDLING, USE AND CONTROL MEASURES AND ALSO TO TAKE LOCAL REGULATIONS INTO CONSIDERATION.

      Fully remove the grease from the area.

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

      2. Use CoMat 01-076 METHYL ETHYL KETONE with CoMat 02-099 LINT-FREE CLOTH.

   2. Immediately dry out area with air blast.

      1. Use oil free air.

3. SUBTASK 72-32-85-350-056 Prepare the Filler Material

   1. Measure out materials by weight.

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

      2. Use CoMat 08-006 FILLER, TWO PACK.

   2. Mix the two parts by kneading until the paste is a constant blue color. No streaks permitted.

      1. Use putty knife.

4. SUBTASK 72-32-85-350-057 Apply the Filler Material

   1. Fill the filler slightly more than necessary level in the damaged area.

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

      2. Use air powered sealant gun.

      3. Make sure that the repair area is fully filled with no air pockets.

      4. If the complete fan track is to be filled to the depth of the GRC layer.

      5. Start at the bottom and work both sides.

      6. The filler will gradually set.

      7. If any sagging is apparent, locally produced supports will be necessary.

   2. Cure the filler.

      1. The cure times and temperatures are given in Figure.

   3. 
      CAUTION
      DO NOT OPERATE WITHOUT SAFETY GOGGLES AND OTHER GUARD EQUIPMENT. FLYING PARTICLES CAN CAUSE INJURY.

      NOTE

      The minimum cure time is one hour.

      Blend the filler to the contours.

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

      2. Refer to Figure.

   4. Remove the debris.

      1. Use vacuum cleaner.

5. SUBTASK 72-32-85-220-053 Examine the repair Area

   1. Examine the surface of repaired area.

      1. Make sure that the filled surface is smooth.

      2. Step is acceptable if less than 0.02 in. (0.5 mm).

      3. If necessary do this TASK again.

      4. Refer to Figure.

Figure: Filling repair of attrition linings

Filling repair of attrition linings



Figure: Curing Chart of Filling Material (CoMat 08-006)

Curing Chart of Filling Material (CoMat 08-006)