(3) On the overhead maintenance panel 50VU:

 (a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.

 (b) Put a warning notice to tell persons not to energize the FADEC 1(2).

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 E 56-5B E E E Subtask 72-54-00-010-085

 B. Open the fan cowl doors (Ref. TASK 71-13-00-010-040):
 FOR 1000EM1
 437AL, 438AR
 FOR 1000EM2
 447AL, 448AR

 Subtask 72-54-00-040-063
 C. Make the thrust reverser unserviceable (Ref. TASK 78-30-00-481-041). Subtask 72-54-00-010-086
 D. Get Access
 (1) Open the thrust reverser doors (Ref. TASK 78-36-00-010-040): FOR 1000EM1 451AL, 452AR FOR 1000EM2 461AL, 462AR

 (2) Let the temperature of parts decrease to ambient temperature.

 4. Procedure
_________ (Ref. Fig. 604/TASK 72-54-00-991-303) Subtask 72-54-00-010-087
 A. Removal for Access to the Inspection Area
 (1) Remove the core nozzle assembly (Ref. TASK 78-11-11-000-041).

 (2) Remove the centerbody (Ref. TASK 78-11-12-000-041). NOTE : The removal of these nacelle hot exhaust components is

____ necessary in order to get an unrestricted access to the turbine last stage, through the rear of the engine. Besides, this inspection necessitates some checks and corrective actions you can do only by hand.
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 Visual Inspection of the Stage 4 Blades Figure 604/TASK 72-54-00-991-303- 13 (SHEET 1)
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 Visual Inspection of the Stage 4 Blades Figure 604/TASK 72-54-00-991-303- 23 (SHEET 2)
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 Visual Inspection of the Stage 4 Blades Figure 604/TASK 72-54-00-991-303- 33 (SHEET 3)
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 B. Inspection of Defects Found during the Borescope Inspection
 (1) Shingling/Unlatching
 CAUTION : DO NOT HIT THE BLADES WITH A DRIFT AND A HAMMER TO PUT THEM
_______ BACK IN THEIR CORRECT INTERBLOCKS. FURTHER DAMAGE TO THE BLADES COULD RESULT. IF NECESSARY, USE ONLY SHAPED TOOLS MADE OF HARDWOOD OR HARD PLASTICS MATERIAL AS PRYING OR PUSHING TOOLS.
 (a) Past experience has shown that it is possible to put back shingled/unlatched blades in their correct interlocking position. To do this, apply hand force as show in sheet 2. (Ref. Fig. 604/TASK 72-54-00-991-303)

 (b) If you can not remove the shingling/unlatching of two blades (or more) do no try further. Let expire the applicable limit extensions. Beyond these, it is up to the airline management to take the necessary hardware actions.

 (2) Hard-facing wear on the blade interlock surfaces.
 NOTE : A worn hard-facing may be at the origin of the shingling and
____ unlatching defects. This condition results in radial and axial mismatches at the blade tip shrouds which are no longer in the same alignment (radial out-of-flush, for example).
 (a) You can measure the interlock wear by the quantity of the aft mismatch of the blade tip shroud.

 (b) Use the honeycomb cells in the outer stationary air seal as a scale to measure the quantity of mismatch. One honeycomb cell is 0.06 in. (1.52 mm) in the largest dimension. If you are not sure, use modeling clay to get an imprint. Then, measure and record the value of the mismatch. The mismatch at the aft edge of the blade tip shroud must not be more than 0.12 in. (3.05 mm).

 (3) Blade pretwist check.
 CAUTION : DO NOT USE PLIERS IN ORDER TO CLOSE THE GAPS AND GET BACK
_______ THEIR PRETWIST ANGLE. IT IS IMPOSSIBLE TO CORRECT THIS CONDITION.
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 (a) An incorrect pretwist is shown by gaps and some mismatch at the blade tip shrouds (sheet 3). (Ref. Fig. 604/TASK 72-54-00-991-303) Result: the adjacent interlock surfaces do not touch each other as they should. This condition is not serviceable.
 - if you see that kind of defects, let expire the applicable limit extensions. Beyond these, let the airline management take the necessary hardware actions
　
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