Please help about to give up on APM

4th time in 2 weeks that i have experienced a near total loss for some reason not known to me copter fly’s ok in stabilize then just like today i switched to loiter it has been other modes in the past ( Drift, Althold and others) and quad goes out of control or flies ok then crashes for no apparent reason Switching back to stabilize does not seem to recover. I dont really under stand the logs so i am sure i am missing somthing
my Quad is ann Iron man 650 4225-610 mtr and 12 inch props My GPS an separate compass e mounted on a mast and and i get 2% interference at 95 % throttle and have isolated vibes to a very minimum with a dual damping system iam sending the most recent log with this any help would be appreciated as i have spent over 1000 dollars in rebuilds
thanks in advance Kyle
PS i am new to quad copters but have 15 + years experience with collective pitch hellis and i read everything so i dont under stand what is up

Do you have the dataflash logs?

The log file you uploaded has your parameters but the dataflash (which is located on your flight controller) has what happened during your flight.

Take a look here for information on how to download the logs: … n-planner/


yes i have the data flashlogs can someone tell me the file extension the files needed and will upload them

The log you upload is correct. Think your modes are setup incorrectly. You stated you switch to loiter mode but the log shows Drift mode.
It also says your GPS-2 went dead at the end. Should not effect Stabilize mode.

Log shows drift and then immediately loiter then back to stabilise which according to the log are the only 3 flight modes you have set up.

It looks like it rolls over quite hard when going from loiter to stabilise. I’m assuming you have the CG set correctly, could you try another flight with full logging enabled? Can see vibrations and rc in/outs motor outs etc and might shed some more light on it.

In my opinion you are experiencing a power failure on your #3 (front left) arm. Here’s my reasoning…

In your logs your BaroAlt matches your RelAlt perfectly so you have no vibration issues. The attached plot shows your Desired roll and pitch values against what your actual roll and pitch values were for the last part of your flight. For most of your flight your actual matched your desired just fine, as it should be. But around line 1310 a divergence occurs and your controlled flight comes to an end.

The actual roll/pitch values show it pitched down and rolled left. This is consistent with a power failure on the #3 arm. It would also be consistent with the #4 arm (rear right) sticking full on power, but that sort of failure is far less likely than losing power.

So what might it be? My first choice would be a flaky ESC on your #3 arm that starts glitching after flying and heating a bit. Second choice would be the #3 motor, but motors are so dirt simple they usually either work or they don’t. But it could be a bad internal motor connection that fails on heating. Last choice would be a bad solder joint or connector on the power feed to that arm (this could include the #3 servo lead to the ESC). Probably least likely as heating wouldn’t be an issue here.

The APM will run a 650 quite well. I have a Pixhawk running a 650 with 17" props that flies buttery-smooth.

Thanks to everyone who replied . Otherhand i do believe your analysis must be right because i am almost certain i don’t have a vibration Issue i have spent many hours balancing an isolating any vibes and i have almost no compass interference. So that said thanks i will rebuild once again an will replace t two motors and two speed controllers if you think that should do it .Also have a brand new Apm controller i was going tom put in a tricopter if you think that might be helpful as a safety mesure
thanks again kyle