AR5 UAV report (2021,PDF): A single bit error switched off the engines

Saw a Tekever AR5 [1] fixed wing UAV on flightradar [2], and that led me to a Serious Incident report where both engines switched off as it was preparing to land. Fortunately an external pilot had line of sight and was able to land the UAV.

It seems that commands are sent as 11 bit values, 50 per second, and the command to send the "Ignition Off" value is any value over a set threshold.

From the doc: "A such, a single bit error would be sufficient to modify the 'Ignition ON' signal value so that it exceeded the 'Ignition OFF' threshold."

(This has now been fixed by the manufacturer so that there must be 10 consecutive Ignition OFF commands)

[1] https://www.tekever.com/models/ar5/ [2] https://www.flightradar24.com/GTEKG/32088166