32-09-03
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
S 865-031
(4) Remove the electrical power if it is not necessary
(Ref 24-22-00/201).
TASK 32-09-03-765-051
3. Inductance and Resistance Test of the Proximity Sensors_______________________________________________________
A. General
(1)
This procedure does these tests:
(a)
Test the resistance of each sensor and wiring.
(b)
Tests the inductance of each sensor and compares it to a known tolerance for the target far and the target near position.
(c)
This task checks the resistance and inductance of the landing gear sensors. For sensors which have high resistance values or bad inductance values, do the FIM 32-61-00/101 to decide to adjust the sensor or replace the sensor.
(d)
For sensors with inductance values too high, you can increase the target to sensor gap to AMM limits to see if this reduces the inductance value.
(e)
To increase inductance values which are too low, you can make the target to sensor clearance smaller within AMM limits.
(2)
This test requires the airplane to be on jacks to swing the landing gear. This allows all landing gear sensors to be tested in the target far and target near conditions.
B.
Reference
(1)
AMM 07-11-01/201, Jack the airplane
(2)
AMM 29-11-00/201, Pressurize the Hydraulic System
(3)
AMM 32-09-03/401, Proximity Switch Electronics Unit (PSEU)
(4)
FIM 32-61-00/101, Landing Gear Indication
C.
Equipment
(1)
Inductance Meter, 1000hz to 5000hz excitation frequency or equivilent.
D.
Access
(1)
Location Zones
117 Main Equipment Center
E.
Preconditions
S 865-040
(1)
These conditions are necessary for this task:
(a)
Electrical power on (AMM 24-22-00/201).
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747-400 MAINTENANCE MANUAL
(b)
Hydraulic systems No. 1 and 4 power on (AMM 29-11-00/201).
F.
Prepare for the test
S 865-050
(1)
Do this task: Remove the PSEU (AMM 32-09-03/401).
S 765-041
(2)
Measure the resistance at the pins on the E3 rack for each main and nose gear sensor.
NOTE: Refer to the Wiring Diagram Manual for the position
____
indication and the air/ground sensors.
(a) If the resistance is greater than 25 ohms, refer to the WDM and fix the problems that you find.
S 765-042
(3)
Measure the inductance at the pins on the PSEU connector on the E3 rack for each main and nose gear sensor.
(a)
Record the inductance value and target position (near or far) for comparison to the inductance values listed in the steps below. See the AMM or FIM 32-61-00/101 or the WDM for a list of sensors and their locations. Also you can use the WDM to note the target position of the sensors you measure.
(b)
Measure the sensor inductances with the gear in both the down and up positions. Refer to AMM 07-11-01/201 to jack the airplane to permit gear retraction.
S 865-043
(4)
Move all the landing gear to the up position.
S 765-044
(5)
Measure the inductance of all landing gear sensors. Record the target positions of all sensors as target near or target far.
(a)
If the inductance for a sensor in the target near position is below 5.2 millihenries or more than 6.5 millihenries, refer to FIM 32-61-00/101 to correct the problem.
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本文链接地址：747-400 AMM 飞机维护手册 起落架 LANDING GEAR 1(66)
