Preliminary Requirements

Procedure

1. SUBTASK 72-32-85-110-083 Clean the Damaged Area

   1. Clean the repaired area.

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

      2. Use cleaning equipment.

2. SUBTASK 72-32-85-220-195 Examine the Damaged Area of the Fan Case (01-100)

   1. NOTE

      Make sure that ultrasonic wall thickness measuring equipment was calibrated by the necessary procedures given in operation manuals of the measuring equipment or local regulations. Calibration piece to be made from the same material (Ti-6A1-4V) or a material with the same acoustic velocity as the part to be tested. The calibration piece thickness must be within the thickness limits of the part to be measured, refer to Figure.

      A replica produed by filling a mold with a casting compound, such as elastomer or plastic and letting it harden inside the impression, taking on the damaged shape and surface details of the original specimen.

      Visually examine and measure the dimensions of the damaged area.

      1. Make sure the damage can be repaired within the specified limits.

      2. Refer to Figure and Figure.

      3. If the damage is within locations 6 and/or 7 it is recommended that the damage depth and the wall thickness of the area adjacent to the damage is noted.

      4. The thickness can be measured with ultrasonic wall thickness measuring equipment.

      5. The depth of damage can be measured with dimensional inspection equipment and CoMat 08-133 SURFACE REPLICATING MATERIAL.

3. SUBTASK 72-32-85-350-061 Blend Repair the Fan Case (01-100)

   1. Refer to Figure, Figure, Figure and Figure.

      NOTE

      Dull tools and worn or loaded abrasive equipments generate heat rapidly and sould be checked frequently and replaced when necessary.

      The blend ratio, length to depth, must be a minimum of 30:1. Refer to Figure.

      Remove the minimum quantity of material necessary to remove the damage. All blends must be smooth and continuous.

      The surface finish of all the repaired surfaces must have the same or better quality to that of the adjacent, not damaged, areas.
   2. 
      CAUTION
      TITANIUM COMPONENT - YOU MUST USE SILICON CARBIDE TYPE ABRASIVE WHEELS, STONES AND PAPERS TO DRESS, BLEND AND POLISH THIS COMPONENT. IF MECHANICAL CUTTERS ARE USED, ONLY LIGHT CUTS MUST BE MADE TO AVOID OVERHEATING THE MATERIAL.
      
      CAUTION
      TITANIUM COMPONENT - AVOID BUILD UP HEAT BY APPLYING ONLY GENTLE PRESSURE AND KEEPING THE TOOL SPEED AS LOW AS POSSIBLE. USE TECHNIQUES WHICH ALLOW FOR PROGRESSIVE WEAR OF THE DRESSING MEDIA TO PRESENT A CONTINUALLY FRESH CUTTING SURFACE TO THE WORK PIECE. DO NOT DWELL ON ONE AREA OF THE COMPONENT. DRESS, WHERE POSSIBLE, IN A CIRCULARY MOTION, TAKING LIGHT CUTS TO AVOID OVERHEATING.
      
      CAUTION
      TITANIUM COMPONENT - YOU MUST MAKE SURE THAT WHEN YOU REMOVE MATERIAL, BLEND AND POLISH, TO MAKE SMOOTH, THAT NO SPARKS ARE PRODUCED AND THE ADJACENT AREA IS MASKED OFF.
      
      CAUTION
      TITANIUM COMPONENT - IF THE MATERIAL SHOWS A CHANGE IN COLOUR DURING DRESSING, TO DARKER THAN A LIGHT STRAW COLOUR, THE COMPONENT IS TO BE REJECTED.
      
      CAUTION
      POWER BLENDING TOOLS MAY BE USED IF DAMAGED TITANIUM PART IS PERIODICALLY CHECKED FOR HEAT BUILD-UP BY TOUCHING OCCASIONALLY WITH UNGLOVED HAND. IF TITANIUM PART BECOMES TOO HOT TO TOUCH, ALLOW MATERIAL TO COOL BEFORE CONTINUING REPAIR.
      
      CAUTION
      THE FAN CASE IS MADE FROM TITANIUM ALLOY AND IS THIN IN SOME AREAS. IF YOU BLEND TOO MUCH. THE PART CANNOT BE SERVICEABLE AND WILL HAVE TO BE REPLACED.
      
      CAUTION
      DO NOT OPERATE WITHOUT SAFETY GOGGLES AND OTHER GUARDS EQUIPMENT. FLYING PARTICLES CAN CAUSE INJURY.

      Blend the fan case surface damage such as dents, nicks, scratches, wear, fretting, galling distorsion.

      1. Use portable blending equipment, CoMat 05-020 WATERPROOF SILICON CARBIDE and CoMat 05-021 WATERPROOF SILICON CARBIDE.

      2. Continue to remove material until all the damage is removed.

      3. The blend must be smooth and continuous into the original contour in all directions.

      4. The surface finish of all blended areas must be as smooth as the original finish.

      5. Refer to the SPM TASK 70-35-03-300-501.

4. SUBTASK 72-32-85-110-084 Clean the Repaired Area

   1. Clean the repaired area.

      1. Refer to the SPM TASK 70-110-26-300-503.

      2. Use cleaning equipment.

5. SUBTASK 72-31-85-220-064 Examine the Blend Repaired Area of the Fan Case (01-100)

   1. NOTE

      Make sure that ultrasonic wall thickness measuring equipment was calibrated by the necessary procedures given in operation manuals of the measuring equipment or local regulations.

      Calibration piece to be made from the same material (Ti-6A1-4V) or a material with the same acoustic velocity as the part to be tested.

      The calibration piece thickness must be within the thickness limits of the part to be measured, refer to Figure.

      Visually examine and measure the dimensions of the repaired area.

      1. Make sure the surface finish is the same as the adjacent material.

      2. Make sure the dimensions are within the specified limits.

      3. Refer to Figure and Figure requirement.

      4. If the repair is within locations 6 and/or 7.

      5. The minimum wall thickness must be measured.

      6. The thickness can be measured with ultrasonic wall thickness measuring equipment.

   2. Examine the ratio of the blended area dimensionally.

      1. Refer to Figure.

      2. Measure the dimensions of the blended areas.

      3. The blend area must have a minimum ratio, length to depth, of 30:1.

6. SUBTASK 72-32-85-110-085 Do a Swab Etch

   1. Clean the repair area.

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

   2. Swab etch the repaired area(s).

      1. Refer to the SPM TASK 70-11-08-300-503, SUBTASK 70-11-08-300-002.

      2. Use chemical etching equipment.

7. SUBTASK 72-32-85-230-067 Do a Crack Test

   1. Do the test for cracks.

      1. Refer to the SPM TASK 70-23-05-230-501.

      2. No cracks are permitted.

8. SUBTASK 72-32-85-350-143 Identify the Repair

   1. Make a mark VRS1405 adjacent to the part number.

      1. Refer to the SPM TASK 70-09-00-400-501.

      2. Use vibro-engraving equipment.

      3. If the repair has been performed in location 6 make a mark VRS1405-6 and in location 7 make a mark VRS1405-7.

Figure: Fan Case Assembly

Fan Case Assembly



Figure: Containment Area of the Fan Case Assembly

Containment Area of the Fan Case Assembly



Figure: FB Flange of the Fan Case Assembly

FB Flange of the Fan Case Assembly



Figure: Fan Case Assembly Blending Limits

Fan Case Assembly Blending Limits