Proximity sensors 

Proximity sensors and switches are used for position sensing of aircraft doors, slats, landing gear, linkages and actuators. Position sensors, in their turn, are often designed around proprietary high-sensitivity technology, incorporating either two-wire passive or three-, four- or five-wire active hermetically sealed sensors.

Landing Gear proximity sensors need to cope with high levels of shock and vibration and with a severe environment. For the Cargo Loading Dock

the space is very limited, while for Thrust Reverser Indication and Door Position Detection a fully hermetic bi-polar switch has to be integrated in the door structure.

The new proximity sensors retrofitted on the Boeing 737 are an enhanced titanium design that greatly improves the sensor reliability in the most harsh conditions. The proximity sensors fit into systems that generally communicate the position status of (for example) flight controls, to other systems on the aircraft, virtually any moving surface operating in a harsh environment that requires reliable, discrete position indication.