Hello I am experiencing some problems with a VTOL tailsitter, specifically in the transition from FBWA to QLOITER. First, there is a strong throttle increase until it reaches the configured angle (70 degrees); then, when the transition is done a strong pitch oscillation starts, which eventually leads to the loss of vertical position and control. Usually I have been able to save the plane immediately switching to FBWA, but this latest flight something happened and when in FBWA the plane started spinning nose down and eventually met the runway. Any suggestion to make successful transitions to have the plane in perfect loitering (as it is when I initially take off?), also if possible without gaining so much altitude trying to put the plane vertical?
Please find attached flight log (there is also an erroneous switch to QLAND in the first attempt because I could not find the right switch on the radio). Thanks in advance.