Uncommanded quadplane low-altitude RTL (4.1.0 Beta1), CUAV V5+

Hi all, Had an aircraft perform an unexpected RTL right after takeoff without any apparent command (failsafe, ground station, RC), resulting in a mild crash (landed out of sight). Any theories as to the cause would be appreciated. My leading theory is that it skipped waypoints 2-10 (which were readback in the TLOG, show up in the bin log, and are still on the plane right now and concluded that the mission was done, so it should RTL.


bin log

I’ll also take this opportunity to plug my suggestion of mode-awareness in RTL. Since RTL appears to have happened immediately after the climb part of VTOL_TAKEOFF (before the transition to forward flight), it would have been a much safer situation end up in QRTL than to transition to plane and start flying back to the launch site at 10-15m. This would also at least give more time to react in situations where people fly in Q modes away from the takeoff site where transition to forward flight might be inappropriate. Yes, this likely would have been the behavior if Q_RTL_MODE = 1, but this wouldn’t have prevented similar issues if outside the RTL radius and effectively disables having the aircraft return to and circle the launch site in fixed-wing mode at the flick of a switch.

@tridge, could you have a look at this one, too? It’s possible the GCS operator hit the RTL button, but IMO unlikely, since their last interaction would have been pushing the auto button up to maybe 10s before the RTL occurred.