Issue: During VTOL-LAND the VTOL would begin the transition from FBWA to QLoiter. After flaring it would level off like normal but instead of descending it would enter a sustained climb in QLoiter.
Background: We have a Foxtech Great Shark VTOL. The VTOL was being operated in an AUTO waypoint mission. This mission began with a VTOL_Takeoff to 75’ then transitioned towards a series of waypoints. These included a long leg out over the water and then a rectangular pattern with a Do_Jump command at the last corner of the rectangle to send the VTOL back to the first, repeating those four corners until otherwise told. After this rectangle a Do_Land_Start was positioned followed by landing approach waypoints. These decrease altitude and end in a VTOL_Land to 0’.
Attempted Fixes: This happened 3 times before we landed it manually. During these occurrences a few different solutions were tried.
- While in Auto mode attempted to descend with RC stick commands but nothing happened.
- Attempted to change to QLOITER (Out of AUTO) and land during climb but nothing happened.
- Put it into guided mode (Loiter) while we rebuilt and reloaded the mission and attempted to auto land again but the climb still happened.
- Changed to FBWA and ran a landing approach, changed it to QLoiter, it transitioned and landed it in QLoiter with no issue.
I am not great with logs and I don’t see anything major that sticks out. I did look through the messages and I see after the land descend started it reset to previous waypoints. Is this normal?
I have looked through some other threads (https://discuss.ardupilot.org/t/vtol-starts-climbing-8m-s-instead-of-landing-at-1-5m-s/74105) and saw one that mentions setting waypoints too close to the VTOL_Land causing aggressive braking and issues resulting in a climb that sounds similar to this. However we have our waypoint set out 300’ and have conducted many missions with these parameters and never had this occur.
Any help would be greatly appreciated. Log is attached.