Mark

When the fueling bay door is fully opened, a proximity switch activates the fueling bay and all associated fueling valves.
  
     
     


This switch is not an inductance device that is used for gear, gear door, and air/ground sensing. The fueling door switch is purely mechanical.
  
     
  

When a magnetic target is moved close, a mechanical switch is made inside the unit.

This type of switch is used in two places on the 767, the fueling door and the APU Inlet  door.