ATA 27-38, Elevator Position Sensor Readings

Typical left/right voltage reading for the elevator position sensor output to the EICAS computers.

The test plug (D6966) is located on the forward side of the EICAS computer rack in the E&E left tunnel. Pins 20 (left) and 17 (right) to ground.

Full travel nose up - 6.5VAC
Full travel nose down - 4.5VAC

767-300
WDM 27-38-11
ASM 27-30-01
AMM 27-38-01

Basic shot of sensor. It can be accessed via a inboard panel under the horizontal stabilizer.



Test plug. Left tunnel, on forward EICAS rack.


Two bolts hold sensor into mount. One of which slides through grove shown in this image.



The sensor comes with a basic "null" line scribed or marked on the face. There is one mechanical stop pin. Adjustment of the actual null needs to be accomplished on the aircraft with the flight control faired.

The system incorporates a couple of in-line filters used on both the sensor signal output and ground wires.



The filters are a capacitor wired to ground on one leg and an inductor wired in series. They are located in the stabilizer jackscrew area at rear of aircraft.




We had an aircraft with quite a history of the left elevator position indication being intermittent. A sensor change did not correct the issue. It turned out to be the output signal filter that was causing the problem.

Great tip about the filter- always something hidden!!