| | | 1ST-STAGE HPT BLADE |
| | | CONTINUE-IN-SERVICE LIMITS |
| CONDITION | .....................................................
| FOUND | BLADE | PERMITTED WITH REGULAR | PERMITTED WITH DECREASED |
| FIGURE 622 | AREA | TIME INSPECTION | TIME INSPECTION |
................................................................................ | Leading Edge | A and B | Two leading edge holes (not adjacent) and two | | Holes and | | blocked trailing edge exit slots on each blade. | | Blocked Cooling| | | | Air Exit Slots | | | | in the Trailing| | | | Edge | | | ................................................................................ | Blocked Cooling| B | Two blocked holes on | All blocked holes if the | | Air Exit Holes | | each blade. | damage is not more than | | in the Tip | | | other damage limits. | ....................................................…........................... | Tip Rub or | B | All quantities, if it is not worn through to the | | Plasma Spray | | internal cavity. | | Deterioration | | | ................................................................................ | Areas where the| A and B | None | None, but that which is | | Blade Parent | | | in the limits for Broken | | Material is | | | or Burned Hole. | | missing | | | | ....................................................…........................... | Airfoil | A and B | None | | Growth | | IMMEDIATELY REMOVE THE ENGINE. | 2................….........…........................…..........................1
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72-00-00
ALL ú ú N01 Page 684U ú Oct 18/99
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
////////////////////////A / PW4000 SERIES /747-400 / ENGINES/MAINTENANCE MANUAL ////////////////////////
No. 17 - HPT (1st- and 2nd-Stage) Blade and Duct Segments, and (1st-Stage)
__________________________________________________________________________ Vane Inspection_______________
(d) ENGINES PRE-PW-SB 72-466; Examine the 1st-Stage HPT blades for airfoil bulges (Fig. 622):
NOTE: Refer to PW SB 72-422 for data about how to point the
____ borescope through the AP-8 and AP-11 access ports.
1) If you use AP-11, examine the 1st-stage HPT blades for bulges (which cause the blade tip to curve): a) Examine the blades for bulges after the first 2,000
cycles and after each 250 cycles or each subsequent "A check". b) If you find a bulge, remove the engine in 25 cycles.
2) If you use a flexible borescope with a guide tube through AP-8, examine the concave side of the 1st-stage HPT blades for dark spots:
NOTE: The 1st-stage HPT blades with airfoil bulging
____ usually have a large dark spot or shadow near the bulge. A dark spot that goes forward of the fifth tip cooling hole is a sign that the blade was too hot, which can cause bulging.
a) Examine the blades for dark spots after the first 2,000 cycles and after each 250 cycles or each subsequent "A check".
b) If you find a bulge or a white spot in a dark spot, remove the engine in 25 cycles.
NOTE: A white spot in a dark spot can be a sign of
____ spalled coating which is caused by a bulge.
c) If you find more than 30 blades with dark spots that go forward of the fifth tip cooling air hole, examine the engine each 20 cycles and remove the engine in 100 cycles.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
72-00-00
ALL ú ú N02 Page 684V ú Jun 18/00
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
No. 17 - HPT (1st- and 2nd-Stage) Blade and Duct Segments, and (1st-Stage)
__________________________________________________________________________ Vane Inspection
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