After more than two hundred flights with my APM2 equipped quad, today, in the remotest of possible locations my quad failed to respond and attempted to fly away by itself! All I can say is thank goodness for Knobthorn trees.

I wanted to get some video of the area but didn't have my small cam with me so I attached my Galaxy Smartphone to the front of the quad, I have done this before and know that the video won't be that great (lots of jello) but will at least give an idea of the scenery. I waited for satellite lock and then hand launched (too much dust on the ground) just in front of where I was standing, I went slowly up to about 20m, hoverered then did a 180deg pirouette and slowly started descending back towards my position.

When the quad was about 3m from me and 2m off the ground I throttled up to stop the descent which was fine but now the quad was drifting forward slowly so I tried to tilt it backwards... suddenly I had that sickening realization that it wasn't responding, I wiggled the sticks...NOTHING!. I ran towards it but it was still drifting forward and climbing very slowly, now at about 2.5m. It continued very calmly and smoothly and I briefly considered throwing the only thing in hand (my transmitter) at it to try bring it down, but it flew on until it collided with a Knobthron tree at about 4m high.

3 motors were jammed by branches but one was still spinning away calmly. I wasn't... I was able to run to the nearby parked pickup and drive under the tree, reach up to unplug the battery and then get the quad down.

I have read the horror stories of fly-aways but one naturally never expects it to 'happen to me'.

- My radio is a tried and tested two year old Hitec Aurora 9 which has one of the most robust AFHSS 2.4GHz systems. The quad was 3m from me when it happened!

- My failsafe is setup correctly and double-tested, with the throttle channel going to 900ms on event of signal loss.

- All four my SS 30A ESC's (2A BEC) power the APM2 (each tested 0.09v of each other) effectively quadrupling the current capacity. I've never had a suggestion of a brownout.

So what happened? I don't know, I can't see anything definative in the logs (attached). If someone has any ideas I'd be very grateful!

As for now my faith in APM2 has been shattered, like an old friend you can no longer trust.

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Graham, please check the voltage coming out of each of the BEC's individually.  This is normally a really bad idea.  I had two ESC's connected in parallel once, and after a few minutes, one of the BECs failed and it sent 12V down the positive wire, and destroyed the servo tester.  That one ESC now permanently outputs 12V.

Just test to see if maybe that happened, and the Rx was just the first to fail?

Maybe your attached Galaxy Smartphone interfered with the receiver, GPS, or both.

I attached a Flip Video to my T-Rex 450 and it interfered very much with the GPS....

Just a thought.....

I've use my old Nexus One in the same way. I never experienced an issue, airplane mode on or off.



incorrect. a cell needs a battery to create a signal.

the am/fm radio does not need a batt

Sorry Andrew, no tlog, didn't have it connected at the time.
They were checked when I first set the quad up , however I will check again. I've been flying electric twins for years with paralleled ESC's with no hassles.
I'll do a full check when I get home but I have checked the plugs, wiring and connections and found nothing erroneous. The quad powers up fine and every thing appears to be working correctly. Haven't flown again yet but will try a tethered flight in a day or two when I'm back. Will post the video too which is quite cool.


I had the same problem a week or so ago.. see the below post... so I would not put too much focus on your cell phone as the root cause.  Also using a Hitec.  As I don't have the skill to properly analyze the logs other than using the Log Visualizer tool I still have no idea what happened.  Maybe the smart people who analyze logs can find some commonality in the events.

Similar to your experience, I rebuilt my quad yesterday and did a simple hover and everything worked fine also indicating no connection issues or loose connections.

I also share your concerns in regards to my faith in this platform.  I have had random issues for quite a while with any feature beyond loiter.  I have been hoping new firmware fixes the problems but they never do. 

My friend bought a APM 2 after seeing mine several months back.  After seeing the flight "randomness" and setup challenges he decided not to fly it and bought a Naza.  Looking forward to see how that flies this weekend.


I was just taking my lunch break and checking the forum, to see if someone else experienced this, and here I go...

Yesterday I downloaded the new 1.2.17 update.  I have had many flights (20-30) with my quad.  I was working with "Auto" mode, testing waypoints and alt hold.  I do not have anything special hooked up to this, just a plain APM 2.0, standard kit from 3DR.  I was having a GPS issue linking up, took for ever, but finally linked up, got a solid blue LED.  So I proceeded.  I throttled past 50% put it into "auto", it bolted  away from me, so I switched to manual response.  As it was stated before, thank God I live in a remote area with a lot of trees.  Looks like I will be purchasing an aluminum frame, as this one is mangled.

When I get home tonight I will attach the tlog.  I have a spektrum DX8, with spektrum recvr.  I've never experienced issues like this before. 

So what was different on this flight? Weather...fair 32 degrees F, new update 1.2.17...


I read your other thread.  As a new APM2.5 user I am also very worried about such failures.  One thing that is extremely odd is that you say you do not have RTL mode set up in your radio yet your google file says you were mostly flying in RTL.  In my own testing, I have never seen a mislabelled mode in the log files.  Have you confirmed the modes it switches in to while connected via USB?

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