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 ALL  ú ú N01 Page 603 ú Jun 10/88
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////////////////////////A / PW4000 SERIES /747-400 / ENGINES/MAINTENANCE MANUAL ////////////////////////
(c)  Cracks are not permitted. 1) Replace the housing if you see cracks (AMM 77-21-05/401).
 S 216-004-N00
 (3)  Examine the temperature inlet tubes (three locations) and the six slots on the leading edge of the housing for blockage. (a) Make sure you can see through the inlet and the discharge ports of the housing. 1) The view (line of sight) through the ports must be 80% free of blockage (minimum). a) Remove the blockage, if it is necessary.
 S 226-005-N00
 (4)  Make sure the temperature discharge slots (three locations) on the trailing edge of the housing are open to the minimum (width and length) dimensions (Fig. 601). (a) Replace the housing (AMM 77-21-05/401) if the slot dimensions are less than minimum.
 S 226-006-N00
 (5)  Make sure the dimensions for the temperature inlet tubes on the leading edge of the housing are open to the minimum (width and length) dimensions (Fig. 601). (a) Replace the housing (AMM 77-21-05/401) if the dimensions are less than minimum.
 S 426-007-N00
 (6)  Install the EGT (TT4.95) thermocouple housing (AMM 77-21-05/401).

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 ALL  ú ú N01 Page 604 ú Jun 18/99
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AIRBORNE VIBRATION MONITORING (AVM) SYSTEM - DESCRIPTION AND OPERATION
______________________________________________________________________
 1.  General
_______
 A.  The airborne vibration monitoring (AVM) system is used to continuously monitor engine vibration levels to detect engine deterioration.
 B.  The AVM system components include one engine mounted accelerometer on each engine and two AVM signal conditioners. The accelerometer senses engine vibration due to N1 and N2 shaft rotation. The signal conditioner uses the accelerometer signals along with N1 and N2 speed signals to determine the level of the individual rotor vibrations for each engine. This information is transmitted to the EIU's where it is processed, and then sent to the auxiliary EICAS for display.
 2.  Engine Accelerometer (Fig. 1)
____________________
 A.  There is one accelerometer installed on each engine just aft of flange A at the 1 o'clock position.
INLET COWL

Airborne Vibration Monitoring (AVM) System Component Location
Figure 1 (Sheet 1)

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 ALL  ú ú N01 Page 1 ú Jun 18/99
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////////////////////////A / PW4000 SERIES /747-400 / ENGINES /MAINTENANCE MANUAL ////////////////////////
DATA PLATE
AVM SIGNAL 
CONDITIONER 
(E2-1) 
SEE  C 
AVM SIGNAL 
CONDITIONER 
(E1-1) 
ELECTRONIC EQUIPMENT  SEE  C 
RACK, E1/E2 
SEE  B 
MAIN EQUIPMENT CENTER 
FWD 
ELECTRONIC EQUIPMENT RACK, E1/E2 
B 

DATA PLATE
AVM SIGNAL CONDITIONER AVM SIGNAL CONDITIONER C1 C2
1
AIRPLANES WITH ENDEVCO S360N021-805 AVM 2
AIRPLANES WITH VIBRO-METER S362A001 AVM
Airborne Vibration Monitoring (AVM) System - Component Location Figure 1 (Sheet 2)
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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)指示 ENGINE INDICATING(56)