A320 PROXIMITY DETECTOR OUTPUT SIGNAL

[B737NG_Pilot]

Hi can anyone explain, what is the significance of the PROXIMITY DETECTOR OUTPUT SIGNAL & GEARS AND DOORS - INTERACTIONS BETWEEN LANDING GEAR AND AIRCRAFT SYSTEMS tables mentioned in the A320 FCOM. How is it relevant during flying?

Also a simple explanation of the two tables would be great.

[Check Airman]

Deeper understanding of the system and its interactions.

[B737NG_Pilot]

Yes wanted to know what it means if anyone can explain

[pattern_is_full]

There are proximity sensors that, among other things, detect whether the gear parts (misc. struts and hinges; doors) are in the correct positions that indicate down and locked, or open/closed, and so on. I.E. if a gear door is not within 2mm proximity of the sensor, that door is not "closed" safely.

Those send an output signal to the aircraft systems, which will then recognize dangerous conditions (gear not down and locked, door not closed) and issue warnings in the form of EICAS indications, flashing lights, and alarm sounds.

They are analogous to the proximity sensors in many home-security systems, which will sound the alarm if a sensor and magnet pair have been separated by someone opening a window or a door.

For a simpler and more obvious example - the radar altimeter is a form of proximity sensor. It measues proximity to the ground. If the aircraft systems receive signals that the aircraft is within, say, 500 feet of the ground - and the gear detectors are not indicating down and locked, a warning will sound: "Landing Gear! Landing Gear!"

[tubby linton]

They basically serve as a ground/flight logic.Some systems have different characteristics in flight or on the ground such as pitot heating.You may not want to fly in icing conditions if your pitots are stuck on low heat due to LGCIU problems

[B737NG_Pilot]

Thanks for the reply pattern_is_full. Already aware of how proximity sensors work, just needed help with the reading of the tables. But thanks to Tubby and you. reading both your replies I was able to get my answer as to how to read the table....

Thanks a ton you both.