In every aircraft knowing the condition or the condition of many components is essential for safe operation; some of the items we need to monitor include the following:
- Door control and indication
- Thrust reverser control and indication (except for GE engine CF6—80C2)
- Landing gear indication and air ground sensing
- Leading edge slat indication and failure protection
How we do this on the Boeing 767 and indeed many other aircraft types use similar is by using sensors which look to see if a known target is near or far away.
This then provide position inputs to the proximity switch electronics unit (PSEU) for the following airplane systems control and indication.
The sensor is a two-wire, magnetic field producing device that is contained in a stainless-steel case with wires connected to the PSEU proximity switch card.
Either cylindrical or rectangular sensors are used depending on installation requirements.
Operation is identical with slight differences in rigging procedures.
The sensor operates in conjunction with a steel target.
The change in inductance as the proximity of sensor and target changes from near to far or far to near is detected by the associated proximity card which switches its output to its associated logic card from 0.3 volt to 13.1 volts (near to far) or 13.1 volts to 0.3 volt (far to near).
When near, the sensor/target inductance is five to eight millihenry’s, and when far several millihenry’s less.
Why not follow on LinkedIn to learn more on our Boeing 767 with the CF6 & PW4000 Engines General Familiarisation Course covering 4 engines which is offered in a Level 1 – 40 hour gen fam