Preliminary Requirements

Procedure

1. SUBTASK 72-44-20-200-001 Unplug the Vane Airfoils and Platforms Cooling Air Holes

   1. Clean the blocked cooling air holes in the vane airfoils and platforms.

      1. Refer to Figure.

   2. Apply CoMat 10-058 PENETRATING OIL to vane cooling air holes.

      1. Permit the oil to soak into material that blocks the holes.

   3. 
      CAUTION
      THE SMALLEST AIRFOIL COOLING AIR HOLE IS 0.017 IN. (0.431 MM). THE HOLES ARE DIFFERENT SIZES FROM LOCATION TO LOCATION. USE A REAMER OR WIRE THAT HAS A SMALLER DIAMETER THAN THE FINAL HOLE SIZE AND INCREASE IN SMALL INCREMENTS TO THE CORRECT SIZE. CAREFULLY PROBE THE HOLES SO YOU DO NOT CAUSE DAMAGE TO THE COATING.

      Hand probe the cooling air holes to remove the foreign material or blockage.

      1. NOTE

         The use of a tapered reamer is recommended for the initial probing of the holes. The spring wire can break off larger pieces of debris and force them into the internal vane cavity. Drill bits can break off and stay in the hole.

         Use a reamer or spring wire with the correct diameter for each of the holes given in the figure.

      2. The use of spring wire with a pin vise can be used between the airfoils if a longer rane is necessary.

      3. Cut the end of the spring wire at an angle.

      4. Hand probe the holes and use a rotary motion.

      5. Move the reamer or wire slowly into the hole while probing.

      6. Remove the tool intermittently and hold the vane with the cooling air holes down to permit the debris to fall out.

   4. Continue to hand probe the airfoil and platform holes to the diameter given in the figure.

      1. Refer to Figure and Figure.

      2. Finish the probing with spring wire. This will minimize the hole taper.

2. SUBTASK 72-44-20-130-056 Clean the Internal Passages on the Vane Assembly

   1. NOTE

      The ultrasonic will increase the temperature of the solution.

      Ultrasonic clean the internal vane passages to remove the debris.

      1. Refer to Figure or Figure. Do the procedure given in SPM TASK 70-13-02-300-503 at a maximum of 150 deg F (65.6 deg C). Use CoMat 01-339 ALKALI CLEANER (GENERAL PURPOSE) alkaline (general purpose) solution. Mix the solution by the procedure given in the SPM TASK 70-11-48-110-501.

         1. Position the vane assembly at different angles when you clean the vane to flush out the unwanted material located inside the internal cavities.

   2. Power flush the vane assembly internally and externally with hot water and air dry.

      1. Refer to Figure or Figure.

3. SUBTASK 72-44-20-200-002 Examine the Repair

   1. Visually examine all the airfoil and platform for cooling air holes that are not plugged.

      1. Refer to Figure or Figure.

   2. If any airfoil or platform cooling air holes stay plugged, do the procedure given in TASK 72-44-330-032 (VRS3609).

4. SUBTASK 72-44-20-200-003 Touch-up the Platforms Coating

   1. If necessary, touch-up the coating on the platforms.

      1. Do the procedure given in TASK 72-44-20-300-012 (VRS3607).

5. SUBTASK 72-44-20-200-004 Examine the Vane Cluster Assembly by the Airflow Check

   1. Do an airflow check on the airfoil cooling air holes.

      1. Do the procedure given in TASK 72-44-20-200-000 (INSPECTION-000) except you can correct the airflow that is under the limits by hand probing.

      2. Increase the hole size in small increments.

   2. The airflow check in the inner and outer platform cooling air holes is not required.

      1. Do not hand probe all the holes at one time or you can create an airflow that is over the limits.

      2. Any vane airflow that is higher than the limit given is not acceptable.

Figure: Stage 1 HPT Vane (PN 2A5591) Cooling Air Hole Repair Areas

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Stage 1 HPT Vane (PN 2A5591) Cooling Air Hole Repair Areas

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Figure: Stage 1 HPT Vane (PN 2A5591) Platform Cooling Air Hole Repair Areas

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Legend

Stage 1 HPT Vane (PN 2A5591) Platform Cooling Air Hole Repair Areas

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