The problem, as more Mode S Interrogators get installed around airports, is weeding out the aircraft with faulty squat switches or problems with the installation. For example, many still respond to the All Call on the ground. Are there any ramp checks that should normally pick up this kind of thing on Mode S? (It's quite rare to find an aircraft still responding to A/C on the ground.) If so how often are they normally performed?
A number of aircraft leave the thing left on when they get to the gate and sit there responding to Roll Call for ages. Is it normally in the SOP to do so and they've just forgotten?
RR