(2)  
AMM 72-33-01/801, Front Fan Case

 (3)  
IPC 72-33-51 Fig. 5

 D.  
Access

 (1)  
Location Zone
 412 Engine No. 1
 422 Engine No. 2
 432 Engine No. 3
 442 Engine No. 4

 E.  
Procedure

 S 866-002-N00
 (1)  
Make sure that the fuel control switches are in the CUTOFF position.

 (a)  
Attach the DO-NOT-OPERATE tags.

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////////////////////////A / PW4000 SERIES /747-400 / ENGINES /MAINTENANCE MANUAL ////////////////////////
SEE A 
POSITION POSITION 3 2  POSITION 1  POSITION POSITION 8 7  A 
POSITION 4  FRONT FAN CASE (FRONT VIEW) POSITION 5  POSITION 6  FRONT FAN CASE A A 
OVER SPECIFIED GROUPS MINIMAL DEPTH, AVERAGE 0.140 INCH (3.556 MM)  GAGE PWA 29156 

MEASURE AT THIS POINT L-A3777 0987
A-A
Front Fan Case Inspection
Figure 601

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S 496-003-N00

 CAUTION:_______ MAKE SURE THAT YOU PUT THE PROTECTIVE MATS ON ALL OF THE LOWER
 HALF OF THE INLET COWL SURFACE.  IF THE EDGES OF THE MATS DO
 NOT TOUCH, PUT THE TAPE BETWEEN THE MATS.  IF THE EDGES DO NOT
 TOUCH, THEN THE TOOLS OR PARTS CAN FALL AND CAUSE DAMAGE TO THE

 INLET COWL SURFACE.
 (2)  
Put the protective mats in the inlet cowl.

 S 226-010-N00

 (3)  
Do these steps to examine the fan case rubstrip for worn areas:

 (a)  
Use an approved dial depth gage with a tapered contact point or a PWA 29156 gage to measure the depth of the worn areas on the rubstrip. 1) Make sure there is no unwanted material in the rubstrip

 groove.
 NOTE: Unwanted material in the rubstrip groove can cause
____ incorrect depth values.
 2)  Make sure the point of the gage touches the bottom of the groove.
 NOTE: It is possible that you must measure more than once
____ at the same position to find the largest depth, because the bottom of each groove is rounded.
 (b)  If you use the PWA 29156 gage to measure the depth of the worn areas in the rubstrips, do the steps that follow: 1) Put the gage in the set master on the surface marked 0.260
 inch (6.604 mm). 2) Set the revolution counter, the dial indicator hand, and the bezel to zero.
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(c)  
Record the position and the depth of the worn areas at the eight locations shown (Fig. 601). 1) Install the gage in the third groove from the front of the

 fan case (flange A). 2) Write the calculated value of the depth for each position.

 (d)  
Calculate the average of the depth values at the three positions for each Group, A through F, as shown in Table 601. 1) The average for each group must not be less than 0.140 inch

 (3.556 mm) in depth. 2) If the average depth for one or more groups is less than
 0.140 inch (3.556 mm), remove the fan case (AMM 72-33-01/401).
 ~............................................................................... | | Positions of | | Positions of | | Group | the Gage | Group | the Gage | .................................................................................
 |  Group A  |  7,  8,  1  |  Group D  |  3,  4,  5  |
　
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