Preliminary Requirements

Procedure

1. SUBTASK 72-00-00-480-051 Prepare the TAP Test Set

   1. Refer to Figure.

   2. 

      CAUTION

      THE TAP TEST SET IS A SENSITIVE ACOUSTIC INSTRUMENT. YOU MUST BE CAREFUL WITH THE TAP TESTER TO MAKE SURE THAT IT CONTINUES TO GIVE SATISFACTORY OPERATION.

      Prepare the IAE 2R18901 Transient Acoustic Propagation (TAP) test set or IAE 2R19921 Transient acoustic propagation (TAP) test set kit 1 off for use as given in the User's Guide.

2. SUBTASK 72-00-00-280-051 Do a Check of the Tap Tester

   1. Do a battery check of the TAP tester.

      1. NOTE

         The Battery can give eight hours of continuous use before it is necessary to recharge it.

         NOTE

         A charge time of 16 hours is necessary for every eight hours use.

         NOTE

         The Battery life is 500 charging cycles, which is approximately 18 months if charged daily.

         NOTE

         If the battery charge is not sufficient for your operation or if the TAP tester does not hold its charge well, a modification is available to increase the battery capacity. A TAP tester which has this modification does not have the multi pin battery connector, but has a larger version of the probe socket. Consult your IAE representative if this modification is necessary.

         Make sure that the display does not show the message LOW BATTERY.

   2. Do a system check of the TAP tester.

      1. 

         CAUTION

         EACH TAP TESTER IS ISSUED WITH A PROBE THAT IS ELECTRONICALLY MATCHED TO THE TAP TESTER. DO NOT CHANGE THE PROBE WITH ONE MATCHED TO ANOTHER UNIT AS THIS CAN CAUSE YOU TO ACCEPT BLADES THAT SHOULD BE REJECTED.

         NOTE

         Make sure that the probe does not touch the blades.

         Connect the probe to the tester.

      2. NOTE

         The message RRM THOR UNIT shows that no pass/fail value has been pre-programmed in to the tester.

         Press the ON switch. The display shows RRM THOR UNIT.

      3. Press the MENU switch. The display shows SYSTEM TEST.

      4. NOTE

         If the display shows a value, the probe has been damaged. You must replace the probe as soon as possible and do the system check again.

         Press the EXE switch. The display shows SYSTEM OK.

      5. NOTE

         This step is necessary to stop the system check.

         Press the OFF switch to turn the tester off.

   3. Do a functional check of the TAP test set.

      1. Apply a small quantity (approximately pea sized) of CoMat 06-148 ULTRASONIC COUPLANT to the plastic insert in the IAE 2R18902 Transient acoustic propagation (TAP) test block or IAE 2R19921 Transient acoustic propagation (TAP) test set kit 1 off.

      2. Put the TAP test block on a table or a flat surface. Attach the probe to the plastic insert. Make sure that the probe is in the center of the plastic insert and the unwanted ultrasonic couplant has not been put on to the metal around the plastic insert.

      3. Press the ON switch. The display shows RRM THOR UNIT.

      4. 

         CAUTION

         DO NOT HOLD THE TAP TEST BLOCK WHEN YOU READ THE VALUE ENGRAVED ON THE SIDE OF THE TEST BLOCK. YOUR HAND WILL ABSORB SOME OF THE SOUND PULSE WHICH CAUSES A FASTER DECAY RATE WHICH GIVES READINGS OUTSIDE THE RANGE ENGRAVED ON THE TEST BLOCK.

         NOTE

         If you can not get the correct value, clean the block and do the functional check again. If you can not get the correct value after three tries, the system has failed. If you get another error message consult the USER GUIDE.

         NOTE

         If the values shown are more than the value engraved on the side of the TAP test block, make sure that the Tufnol base has not been bonded to the test block and that the Base is free to rotate.

         NOTE

         If the Tufnol base is tight on the test block the base will absorb some of the sound pulse, this gives a faster decay rate. If necessary, the Tufnol base can be removed and the fit loosened by machining out the inside diameter.

         NOTE

         Do not remove the Tufnol base for the functional check because different types of work surface will absorb different quantities of sound. This can cause faster and inconsistent decay rates.

         Press than EXE switch. The display shows a value. Make sure that the value shown on the display is in the range of values engraved on the side of the TAP test block.

3. SUBTASK 72-00-00-280-052 Do an Inspection of the Fan Blades

   1. Refer to Figure.

   2. Apply a small quantity (approximately pea sized) of CoMat 06-148 ULTRASONIC COUPLANT to the lower convex airfoil adjacent to the annulus filler line.

   3. Attach the probe to the fan blade.

   4. Press the ON switch.

   5. 

      CAUTION

      DO NOT HOLD THE FAN BLADE WHEN YOU READ THE VALUE. YOUR HAND WILL ABSORB SOME OF THE SOUND PULSE WHICH CAUSES A FASTER DECAY RATE.

      NOTE

      If the display shows the message COUPLING FAILURE, apply more CoMat 06-148 ULTRASONIC COUPLANT and do the inspection again.

      Press the EXE switch. The display will show the value or message in approximately four seconds.

   6. If the display shows more than 700 dB/see, reject the blade.

Figure: Transient Acoustic Propagation (TAP) Test Set

Transient Acoustic Propagation (TAP) Test Set



Figure: Probe Position During TAP Test

Probe Position During TAP Test