Preliminary Requirements

Procedure

1. SUBTASK 72-00-00-490-058 Calibrate the Ultrasonic Detector

   1. Set up ultrasonic flaw detector for dual or through transmission, with zero delay.

   2. Set amplifier switch to 5 - 10 MHz.

   3. Apply CoMat 06-148 ULTRASONIC COUPLANT to rear angled flank and position probe on IAE 2R19315 Test block QC6827.

   4. Identify signal produced by the large slot A. With range control, position this signal at division line 5 on time base and adjust amplitude to approximately 50 percent screen height.

   5. Increase the gain by 20dB. Move probe over slot B and identify signal produced. Adjust amplifier to bring signal to 60 percent screen height.

   6. If a monitor gate is available, position it between 4.5 and 5.5 division lines on time base. Adjust any visual or audible alarms to trigger at 60 percent screen height.

2. SUBTASK 72-00-00-270-053 Examine the Root Flank of the LP Compressor Fan Blades

   1. Refer to Figure.

   2. Apply CoMat 06-148 ULTRASONIC COUPLANT to concave surface of blade root flank.

   3. Position probe at front of leading edge of concave blade root flank and move probe along full chordal width of blade.

   4. Monitor signal very carefully as you move probe, from front to rear of concave surface.

   5. If a signal greater than 60 percent screen height is produced between 4.5 and 5.5 division lines on time base identify the locations of all indications over 60 percent screen height from the root front face and record on the proforma (refer to figure 802) the ultrasonic signal percentage height and position from the front face. Then perform paragraph E or F depending on the standard of blade.

   6. This procedure applies to fan blades that are pre SBE 72-0375 or pre SBE 72-0384 only. Fan blades that have failed ultrasonic inspection can be further inspected using binocular inspection to establish if they are serviceable.

      1. Subsequently to the above, perform a x30 binocular inspection at each indication position (refer to paragraph 5). Reject any blades where cracking is confirmed by this inspection.

      2. On any blades rejected during step 1, identify the locations of any such indication(s) on the blade and record on the proforma (refer to figure 802) the ultrasonic signal percentage height and position from the root front face and advice the IAE Representative.

      3. If no cracking is present after step 1, the blade is considered suitable for completion of any further engine manual inspection/rework operations required to return it to service operation. On any such blade, record on the proforma that a x30 binocular inspection has been successfully completed with no cracking being detected.

   7. This procedure applies to fan blades that are post SBE 72-0375 or post SBE 72-0384 only. Fan blades that have failed ultrasonic inspection can be further inspected following removal of the Metco coating using the procedure that follows.

      1. Perform a repeat Ultrasonic Inspection in accordance with paragraph 6 of this procedure.

      2. On any blades rejected during step 1, identify the locations of any such indication(s) on the blade and record on the proforma (refer to figure 802) the ultrasonic signal percentage height and position from the root front face and advise the IAE representative.

      3. If no cracking is present after step 1, the blade is considered suitable for completion of any further engine manual inspection/rework operations required to return it to service operation. On any such blade, record on the proforma that the Ultrasonic Inspection was successfully completed following Metco 58 removal, with no cracking being detected.

      4. Blades that have passed the inspection in step 1 must have the Metco 58 coating replaced in accordance with TASK 72-31-11-300-032, before being returned to service operation.

   8. Repeat this procedure on convex blade root flank.

   9. If any blade is rejected do a detailed inspection of the fan disc, including a x30 binocular inspection of the fan disc dovetail slots (Ref TASK 72-31-12 Inspection/Check). Advise the IAE representative of the findings of the fan blades and fan disc inspection.

3. SUBTASK 72-00-00-280-055 Binocular Inspection on a Fan Blade Rejected following the Ultrasonic Inspection (Pre SBE 72-0375 and Pre SBE 72-0384)

   1. Introduction.

      This technique covers the additional binocular inspection of V2500 fan blade roots for possible top edge of bedding cracking, detected by ultrasonic inspection as shown in Figure.

      The person carrying out this inspection should be proficient at binocular inspections. Additional specific training is recommended for this inspection, contact IAE.

   2. Preparation.

      1. Ensure that dry film lubricant (DFL) has been removed from the fan blade root TASK 72-31-11-100-002-A00 for Non Metco 58 coated root.

   3. Inspection.

      1. Position fan blade in mounting fixture to view side of the fan blade root presenting an ultrasonic indication.

      2. Adjust lamp to optimum illumination position for highlighting top edge of bedding at ultrasonic indication position, refer to Figure.

      3. Set magnification of binocular to x10 and bring the top edge of bedding at the ultrasonic indication position into focus. Adjust magnification to x30 and re-focus if necessary.

      4. Slowly traverse along the blade, inspecting the top edge of bedding 10mm either side of the ultrasonic indication position, refer to Figure.

      5. NOTE

         The inspection should cover the area approximately 2mm above and below the top edge of bedding. Re-focus the binocular and adjust the lamp as required.

         Check any suspicious features by inspecting at the highest magnification available.

      6. Repeat steps (1) to (5) above for each ultrasonic indication position.

   4. Rejection criteria:

      1. Reject any blade exhibiting a crack like feature running axially along the root in the inspected region.

      2. Reject any blade exhibiting a 'scar' or crator like feature.

4. SUBTASK 72-00-00-280-056 Ultrasonic Inspection on a Fan Blade Rejected Following the Initial Ultrasonic Inspection (SBE 72-0375 and SBE 72-0384)

   1. Introduction.

      This technique covers the repeat ultrasonic inspection of V2500 fan blade roots for possible top edge of bedding cracking, detected by the initial ultrasonic inspection, refer to Figure.

   2. Preparation.

      1. Ensure that dry film lubricant (DFL) has been removed from the fan blade root TASK 72-31-11-100-002-B00 for Metco 58 coated root.

      2. Remove the Metco 58 coating in accordance with TASK 72-31-11-300-032.

   3. Inspection.

      1. Repeat the examination of the root flank as described in Paragraph 4.

   4. Rejection Criteria.

      1. Rejection criteria are as per paragraph 4.

Figure: Schematic diagram showing position of probe on concave root flank

Schematic diagram showing position of probe on concave root flank



Figure: Inspection Proforma

Inspection Proforma



Figure: Inspection areas

Inspection areas