Use of transponders on the ground
I thought it would be easy to find a reference to the correct protocol regarding the use of transponders on the ground.
Obviously at SMGCS equipped airports, aircraft transponders should be switched on before pushback/taxi until back on stand but what about airports where no such equipment is used?
My company's procedure at a non SMGCS airport (99.9% of our ops) is to switch it on just before line up and switch it off after vacating the runway but is this "best practice"?
May I ask what is SOP for other airlines?
Would also appreciate if anyone is aware of any published guidance on this subject relating to UK ops. I have waded through the Eurocontrol and CAA sites to no avail.