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.<p>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.<p>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."<p>(This has now been fixed by the manufacturer so that there must be 10 consecutive Ignition OFF commands)<p>[1] <a href="https://www.tekever.com/models/ar5/" rel="nofollow noreferrer">https://www.tekever.com/models/ar5/</a>
[2] <a href="https://www.flightradar24.com/GTEKG/32088166" rel="nofollow noreferrer">https://www.flightradar24.com/GTEKG/32088166</a>