Hello APM-Friends,
I recently bought an APM 2.5, loaded the firmware for arduplane, configured everything and tested it on the ground. It seems like everything is working fine. Still on the ground, FBWA and Stabilize-mode react in an appropriate way to the movements of the plane. I’m a completely new to APM, so maybe I saw this wrong, but I actually don’t think so. No exaggerated movements of the rudders, ailerons or elevator.
So I set everything up and was ready for my maiden flight with the APM. In Manual-Mode everything was great and as always, but I since I turned on FBWA or Stabilize, the plane reacts in some very crazy way. I think the APM pulled like every control surface to its maximum and the plane was getting uncontrollable. After like 1 second I had to return to manual, because the plane was falling out of the sky. I don’t know what is going on there, because even with normal position of the control sticks, the plane pulled up or down or left or whatever. I’m really not able to describe it, because the plane just did “something” crazy, but not flying normally…
One possible reason could be the vibration. In order to test this theory I tried the FBWA Mode without Throttle, to reduce the vibrations from the motor. But even there the plane was uncontrollable falling from the sky. So I think, this cannot be THE reason.
Another thought is a malfunction of the gyros or accelerometers. I connected an XBee to the plane and watched the artificial horizon and everything seems to be fine. But I guess the artificial horizon uses the gyros, but not the accelerometers. Maybe these could cause the problem, but I don’t know. This is why I’m writing the post 
I will paste one log here in an attachment and hopefully some experienced person is able to help me here.
Greetings,
iSchlachter
The most common cause is control reversal. You don’t seem to have a lot of confidence in how it’s working.
Describe how the controls move when you rotate the plane in FBW while on the ground.
Video is always the best way to show us what is happening.
Well, this was THE reason. Honestly I have to say that I skipped that part in the manual. I really don’t know why, I think I thought something like: I never reversed my servos, so everything has to be fine. But I was wrong…
Luckily, I was able to get the plane always out of trouble, so I never crashed.
Today morning, I just went to the field and tested everything. All functions are working as they are supposed to. Thank you so much! APM is so cool 
Best,
iSchlachter
[quote=“iSchlachter”]Well, this was THE reason. Honestly I have to say that I skipped that part in the manual. I really don’t know why, I think I thought something like: I never reversed my servos, so everything has to be fine. But I was wrong…
Luckily, I was able to get the plane always out of trouble, so I never crashed.
Today morning, I just went to the field and tested everything. All functions are working as they are supposed to. Thank you so much! APM is so cool
Best,
iSchlachter[/quote]
Woo! Good work.
PIXHAWK is cooler