Incident happened during initial testing and tuning of a new a Heewing T1 VTOL (small tiltrotor VTOL). The model uses a Matek H743 Wing V2 with the latest stable Arduplane fw (4.3.7) and bdshot. Radio controller was Radiomaster TX16s running latest stable OpenTx with ELRS 3.2,1 (mode sw ch. 6.).
After having performed Quicktune), I landed and shortly thereafter took off again to evaluate the tune. With the model hovering a few meters from me and close to the ground (testing q_loiter and q_stabilze), the low battery failsafe triggered QRTL and the model started ascending (bat_fs_low_act was set to 1=RTL). At about 3m altitude I opted to abort the failsafe by changing the flight mode (toggled the flight mode-switch into and out of QRTL). When doing so all three motors stopped immediately, and the model fell nose first to the ground. There was no damage to the model (soft ground).
This makes me wonder, and below are some thoughts.
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I cannot see that changing into QTRL and back to q_stabilize (or q_loiter) should trigger disarm during battery low failsafe?
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Would it make any difference if I toggle between q_loiter and q_stabilize instead? It should not, but it makes me wonder.
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Possible bad Arduplane settings on my behalf?
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Bug in the Arduplane/VTOL code?
I have checked the logs, but I hope someone more knowledgeable than me can have a look at it (link below) 
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Regards Ronny Sandslett
