I took my Iris out today for a survey and had a very scary experience. I've had the Iris for almost half a year now and have flown many missions and have logged many hours of manual flying, so I'm a fairly competent flier. I normally fly missions, but since I was surveying a small area, I decided to fly the Iris manually (in loiter mode) A couple of seconds after take off, the Iris became very hard to control and starting listing strongly towards one direction. I had to yank the control stick all the way towards the opposite direction to keep it from flying away. I desperately tried to land the Iris, but it was hard to do so as it was flying very erratically. I switched to alt hold mode after a few seconds to see if that help. Thankfully the Iris became a bit better behaved, but still almost impossible to control. After many nervous seconds, I was finally able to land the Iris into a bush. I'm so glad I didn't fly into a power line or hit a house. Some other observations:
- The yaw and altitude control were working ok
- The roll and pitch was not. The quad strongly wanted to fly in one direction
- The behaviour became slightly better after switching to altitude hold mode, though still almost impossible to control.
Thankfully I have the flight log (attached). You can see the erratic flight path..
I also had a GoPro attached and it was taking time lapse pics. Happy to send those as well if it helps with debugging.
Really thankful that I didn't run into something and was able to recover the Iris with only minor damage. I really would like to understand what happened here. Malfunctioning orientation sensor/GPS? I ran the log through mission planner and except for a DCM Bad Heading message towards the end of the log, don't see any other error messages.
I'd really appreciate if someone can help me diagnose what's happening here. I don't want to fly again until I know what happened with this flight.