4) Install the front segment of the inlet cone (AMM 72-31-01/401).
(b)
Operate the engine with the counterweights installed to make sure that the engine vibration is within limits.
(c)
Remove the MTI interface cable, jumper cable and engine selector switch box.
TASK 72-31-00-725-104-N00
5. Balance the Front Balance Plane (On Airplanes with Vibro-Meter AVM__________________________________________________________________ P/N 241-280-051-012)._______________________
A. General
(1)
The trim balance procedures should decrease the vibration levels of the fan to less than 4.0 units on the airborne vibration monitor (AVM) during a ground operation at all engine operation speeds.
(2)
This procedure uses the aircraft AVM to lower fan ("A" flange) vibration levels only. This procedure should not be used to correct cabin noise problems.
(3)
Trim balance can decrease engine vibration. The trim balance procedure adds a small amount of weight to correct unbalance. The weight(s) are installed on the compressor front balance plane. The trim balance procedure can be done on the engine while it is on the airplane.
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72-31-00
ALL ú ú N01 Page 530 ú Jun 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
(4)
A fan plane balance will affect the low rotor vibration levels on both the fan ("A" flange) and turbine ("P" flange) cases. Because the AVM only has vibration pick-ups on the fan case, the affect of a fan plane balance on the turbine case will not be known. Therefore, this procedure has a limit of the qunatity of weight that can be installed to the fan balance flange. A turbine plane balance cannot be done with this procedure.
(5)
Trim balance is only used to correct stable low rotor related (1EL) vibration.
(6)
The total vector sum of the trim balance weights and the weights installed for component (LPC) balance must not be more than the limits that follow:
Fan Plane: 20 oz-inches (14,400 g.mm)
NOTE: If it is necessary to add more correction weight,
____ you must examine for incorrect assembly and part damage.
(7) Identify all the trim balance weights permanently with the letters "TB".
NOTE: The balance weights installed on the fan hub during LPC
____ balance are not identified with the letters "TB".
(8)
This task gives the instructions for these subtasks:
(a)
Listing of available fan plane counterweights.
(b)
Instruction of the installation of the counterweights.
B.
Equipment
(1)
PWA 85306 Puller - Pratt & Whitney
(2)
PWA 85307 Puller - Knocker, Pratt & Whitney
(3)
PWA 85234 Riveter - (Flaring Pliers, for Fan Weight Rivets)
Pratt & Whitney
(4)
ENGINES POST-PW-SB 72-385;
0.190-32 Jackscrews - 8 are necessary
(5)
ENGINES PRE-PW-SB 72-385;
PWA 83507 Puller - Pratt & Whitney
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
72-31-00
ALL ú ú N01 Page 531 ú Jun 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
////////////////////////A / PW4000 SERIES /747-400 / ENGINES/MAINTENANCE MANUAL ////////////////////////
(6)
Mat - Protective, 3/8 Inch Minimum Thickness, Minimum 42 Inches by 60 Inches With Warning Streamers (commercially available)
C.
Consumable Materials
(1)
G00846 Pencil - Silver
(2)
D00504 Petrolatum - White
(3)
D00390 Oil - Engine
(4)
G00949 Ink
(5)
D00601 Grease, Graphite, high temperature - SAE AMS2518 (CP2101)
(6)
G02326 Pen, Marking - (C05-003)
D.
References
(1)
AMM 71-00-00/201, Power Plant
(2)
AMM 71-00-00/501, Power Plant
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本文鏈接地址：747-400 AMM 飛機(jī)維護(hù)手冊(cè) 發(fā)動(dòng)機(jī) ENGINE 1(128)
