Arducopter Crash analysis request

Yesterday I had several successful tests of Loiter mode, so today I decided to continue testing in windier conditions. 

After confirming that I had a GPS 3D fix, I switched to Loiter mode. It was windy and gusty, but the quad seemed to be doing well. After a while, though, it looked like the deviations from the loiter position were getting larger, so I switched back to Stabilize mode to bring it back to base.

That’s when the problem started. The quad started to move away from me. And very rapidly too. So much so, that I found I was holding the pitch stick full towards me. Yet it continued to drift away. For a bit it recovered, but then it flew away even faster. Eventually I lowered the throttle and deliberately crashed it into the hillside.

I had to trek up the hill to retrieve it. When I reached it some 15 minutes later, one of the props was still spinning. One other prop was stalled and the motor was hot. Luckily it survived mostly intact. Electronics, ESC, motors are all OK. After I replace the booms and a couple of props, it should be good to go again.

I’ve attached the telemetry log. I am hoping someone can help me figure out what went wrong.

Some theories:

[1] I lost orientation and the control inputs were inadvertently directing the quad away from me rather than towards me. I know I had the pitch stick pulled all the way back. The logs show that the quad didn’t yaw around to face me (till the end). So I don’t think that’s what happened.

[2] The wind overpowered the quad. However, it was able to counter the wind in Loiter mode. And the quad has decent power with 4x160 watt Avroto motors turning 11x4.7 props.

[3] Lost Radio signal. But then I was able to lower the throttle to crash-land the quad ...

[4] Since it was fighting the wind in Loiter mode, it accumulated a large I-term (windup) that required a large control input offset. (I remember this from the early days of Arducopter 2.0 code last year).

3690918025?profile=originalAttached: Telemetry Log

Details: APM 2.0, Sonar, Xbee, 2.4.1

2012-03-05 12-35-39.tlog

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –


  • I had a similar problem with my quad.  I never went out of stabilize, though.  It was night and I hovered in the front yard for a while, then went straight up.  I pushed forward and everything seemed fine until I tried to pull back.  It never stopped going forward.  I am watching my bird fly away and I am in a residential area (no hill to crash into).  At one point it was 1/4 mile away at 750 ft altitude.  I got it turned toward me thanks to all the lights I have that indicate which way it was going and got it back down my street.  It was moving fast and I had to hit a tree to stop.  I thought this thing was going to kill somebody!  Thankfully it crashed and fell onto the asphalt busting a few things up.  Scared the crap out of me!


    I was using 2.3.xx, not sure.  I have lost trust in this.  Too much experimentation for where I am in trying to fly.  I like the idea and I am sure it will eventually be solid, but I had to go buy a commercial controller for now.  Trust in the control electronics is fundamental for me.

  • Moderator

    Have you got the .log file as well, as I couldn't get your .tlog to play.

This reply was deleted.