We had a potentially life threatening incident at a Jet & Large Scale Fly-In recently. A 1/3 scale Wilga had just completed an aerotow when the pilot, who is very experienced and safe pilot, suddenly lost all comms with the model. The model circled under free flight for 5 minutes before descending in a lazy spiral earthwards. At one point it looked like the model would crash into the pits and we had to start getting spectators to exit the area rapidly. Scary how the non-modelling public just don't sense the danger as we modellers do. It really took some doing to get the people out of harms way. Luckily the final turn of the model took it away from the pits and it crashed on the other side of the runway.

Turns out the battery failed. New battery freshly charged overnight and suddenly nada, zip! If ever there was a case for mandatory battery back up systems in large planes this was it.

Ross