I just noticed this old post.....
Whilst twiddling the knobs at Speedbird London, I often had test calls from the A/C HF "Boxes", by technicians checking the equipment, after maintenance or repair.
These calls were often transmitted from inside a hangar or the apron out front.
There was never a concern raised, that I heard of, about a possible fire hazard, plus, Kerosene is much less volatile than Petrol.
Although the A/C were on the ground and often physically underneath the station, (3rd Floor Tech Block "A") the received signal was often very weak and difficult to hear because
the transmitting and receiving aerials were, latterly, remotely located near Guildford and Farnborough!
Speedbird London R.I.P.