(13)
Remove lockwiring and fine adjust sensor by using knurled thumbnut on microadjustment rod until VTVM reading is within + 0.03 volts of calculated voltage.
(14)
Drive stabilizer leading edge down and verify that voltage decreases. This is to ensure that neutral shift sensor is set to the correct side of null. If not, repeat steps (10) thru (14) until correct null is obtained.
(15)
Lockwire knurled thumbnut to microadjustment rod.
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E. Return Airplane to Normal
(1)
Depressurize hydraulic systems A and B (Ref 29-11-0 and 29-12-0).
(2)
Open pitch channel circuit breakers.
(3)
Disconnect breakout cables and VTVM.
(4)
Connect D-375 to right power control unit and D-377 to neutral shift sensor.
(5)
Replace access panel.
(6)
Close pitch channel circuit breakers.
(7)
If no longer required, remove electrical power from the airplane.
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2. Elevator Neutral Shift Sensor Test
A. Equipment and Materials
(1) VTVM - Hewlett Packard, Model 410C, or equivalent with suitable leads and adapter to use test points on front of pitch channel.
B. Prepare to Test Elevator Neutral Shift Sensor
(1)
Apply electrical power to the airplane and energize load control center P6.
(2)
Provide system B hydraulic power (Ref 29-12-0 MP).
WARNING: MAKE SURE ALL PERSONNEL AND OBSTRUCTIONS ARE CLEAR OF AILERON, ELEVATOR, OUTBOARD SPOILERS AND RUDDER SYSTEMS. SURFACES AND CONTROLS MAY MOVE ABRUPTLY WHEN HYDRAULIC POWER IS APPLIED.
(3)
Ensure the following systems are energized and operating (Ref Chapter 34):
(a)
Attitude Reference System
(b)
Compass System
(c)
Air Data Pressure Instruments
(4)
Ensure autopilot pitch channel and INTLK circuit breakers are closed.
C. Test Elevator Neutral Shift Sensor
(1)
Set the stabilizer for three units of trim.
(2)
Open autopilot stabilizer trim circuit breaker.
(3)
Move the control column back and forth through neutral a few times to ensure elevators are operating.
(4)
Engage the autopilot pitch axis.
(5)
Ground TP-6 on the pitch channel.
(6)
Connect VTVM to TP-10. Indicated voltage should be 1.75 +1.0/-0.5 volts ac.
(7)
Ground TP-15. The voltage at TP-10 should decrease to 0.0 + 0.5 volts ac.
(8)
Remove grounds from TP-6 and TP-15.
(9)
Remove VTVM from TP-10.
(10)
Disengage the pitch axis.
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D. Return Airplane to Normal
(1)
Depressurize hydraulic systems A and B. Refer to 29-11-0 and 29-12-0.
(2)
Close autopilot stabilizer trim circuit breaker.
(3)
Determine whether there is any further need for electrical power on the airplane; if not, remove power.
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ELEVATOR NEUTRAL SHIFT SENSOR - REMOVAL/INSTALLATION
EFFECTIVITY
SA ZS-SIA and on SD ST-AIB and on WA N235WA-N241WA GJ B-2509 and B-2510
1. General
A. The elevator neutral shift sensor is mounted on the forward left side of the feel and centering unit located immediately aft of bulkhead station 1156 (Ref Chapter 27, Elevator and Tab Control System).
2. Remove Elevator Neutral Shift Sensor
A. Remove tail cone access panel 3802 (Ref Chapter 12, Access Doors and Panels).
B. Open autopilot AC circuit breakers on P6 and P18 load control centers.
C. Disconnect sensor electrical connectors.
D. Loosen screw in sensor crank and remove crank from sensor shaft.
E. Loosen screw in sensor clamp and remove sensor.
F. Note orientation of sensor clamp, then remove sensor clamp.
3. Install Elevator Neutral Shift Sensor
A.
Set horizontal stabilizer at 0 degrees, equal to B dimension of 41.57 士0.05 inches (Ref Chapter 27, Horizontal Stabilizer Trim Control System).
B.
Ensure mach trim actuator is extended (Ref Chapter 27, Elevator and Tab Control Systems).
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