slim spoke
I was playing the game with my friend who's only played once before. After getting a re-arm point that was a heli pad (known bug I think), I started the plane as normal and noticed the TGP was on. Later in the flight, my friend mentioned that the TGP said no signal when it was clearly on from my POV.
I was the owner of the aircraft and in the pilot seat, he was the instructor and was in the vehicle before and after the re-arm (as in was not a freshly spawned in player).