I upgraded from 3.2 to 3.3 recently and had a near-flyaway crash immediately upon arming in Stabilize mode the 1st time after the upgrade. No problems with 3.2. All the standard recalibrations and preflight checks prior to 3.3 test flight.
Today I rebuilt the quad and did some bench tests with the props off to figure out what happened. I discovered that in Stabilize with the throttle a ZERO - Pixhawk commands a throttle of 41% (my throttle-mid parameter). Just bumping the throttle up a hair results in the motors slowing down and spinning at the throttle-min (“70” or 7%). I changed the throttle-mid to “500” and sure enough, 0% stick position results in a motor speed output of “50%”.
RC cal is fresh and correct. There is no expo or non-standard endpoints in my Futaba. Nothing changed on the quad or the RC controller between 3.2 and 3.3. But you can image that it was quite the surprise to arm the quad and have it take off with my throttle at ZERO. But again, bumping the throttle to >0 results in the expected throttle output.
Any ideas?