I got a pretty bad crash today. Everything was flying very nice and suddenly lost altitude and crashed.

The APM board survived, and some motors were very hot, but all of them are gone. 

I can't find any tutorial on how to find evidence on the crash to find out what was the problem... was it a motor? a ESC? an APM bug/crash?

I am attaching the log files to see if someone can give me a walk through on this and find out what could be the problem... meanwhile I get my replacement parts ;)

Thanks guys!



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Do you have any telemetry log file (tlog)? This would be also good.

Thanks criro! I am attaching both tlog and rlog. Hope it helps to find what is happening :/


Log analysis is described HERE.. 

Your code has the Vcc 'noise' issue that criro1999 has in THIS post.

Are you flying a Hex?


Oh my! Thanks for checking it. I will read the entire thread and come back.

Correct, I am flying a Hex.

Thanks Doug!

It looks it was a bug for Vcc on previous 2.9.1b. I believe you don't have the latest 2.9.1b.

Latest version did fix that. Your Vcc ( below) looks as spikes, intead of "linear" values, I did find that myself and I had a crash also. Then team did fix it and on last 2.9.1b, Vcc looks better, without spiking to zero volts.

Also I did see like 46 logs in your APM. I did read also there was sime limitation which could saturate the buffer for logs and this could affect APM. Maybe it was fixed, but it is better to remove logs periodically,


Thanks so much! I will erase/format apm and re-upload the code, also clean all logs and check the Vcc. It's weird that it was the same 2.9.1b, and there is a version of the same software that might be "good"...

I read the entire thread and there is no really a "solution", but to clean up the logs and re load the software. Will do that anyway... I decided that after my crash that cost 800 dollars, this would be my last try on the hobby ha!

One question, have you tried any of the 3.0 rcs? In rc1 there is a specific note on bug fix for the Analog read... is it more stable? 


Your crash costs you $800? Is a complete lost?

I did install 3.0 but when I did try to use the Level function (level, left, righ, up, down, back) it did not work for me and other. It is hanging to first step. Someone suggest to use the CLI Level, but even that was not working for me.

Now I am with 2.9.1b. But I will try next days again 3.0, maybe there are some new fixes.

I replaced all motors, it fell upside down and all had bent shafts and/or torn magnets, each in ~50 bucks Avroto 2814

6 x 50 =  300

Ublox GPS = 76

bent battery 6600= 129

Go Pro = ~300

I am waiting on my telemetry replacement cable, which I found it was also torn, and now with this info I will not fly without telemetry. Meanwhile I will test level on rc2.

Thanks so much criro!

Hi Doug,

Why does this problem only affect Hexcopters? I also have had my hex fall suddenly for no reason, while in Alt Hold.


From what I understand, it affects both Quad and Hexas


The question I would ask, is why only on Alt Hold... and not in Stabilize.

Also, it is unknown from what I get, if the 2.9.1b that someone installs is defective or not, unless you check the Vcc parameter in the Tlog. Also, seems, but haven't found for sure, that having a lot of logs in the APM board could cause this, but again, nobody can really confirm.

I suppose is one of the beauties of working in open source software, ha!

The joy of flying a do it yourself drone. LOL. I always make it a habit to delete logs after each days flying. The most I can fly would be 4 missions. I've had my share of brownouts and unexplained drops from the sky. Most of my crashes have been pilot error or poor wiring on my part. But lately its been upsetting, cause there's no reason for the crash. I thought it might be the 3DR power module, but now I'm not so sure. I plan on loading 2.9.1b after a reset and check my Vcc in Tlogs. Even after all the crashes and expenses, I still get a thrill out of flying something I built. Very satisfying.
Good luck and fly safe.

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