Iris+ with 3.2.1 descends on its own, crashes

I was flying my Iris+ a bit ago and it was all going smoothly when I switched to loiter. It just cut throttle and fell, so I switched back to althold and it recovered a bit then just started falling again. I almost got it back but it went into some rocks and crashed. The logs looks like the copter intentionally reduced throttle on all 4 motors but for the life of me I can’t figure out why. My throttle input was at max yet the copter just went down. No fail safes appear to have been triggered. I’m upgrading to 3.4 when I rebuild but I want to make sure there are no underlying issues that I don’t know about. Thanks all.

Here is the dropbox link to the log

Logs show that the copter was not able to maintain altitude. It most of hit a down draft or something and it looks like the copter maybe over weight and not able to generate enough lift to keep it in the air. At high altitude the air is thinner and requires larger props.


I had Solo 1045 props on there and I originally thought that but why would RCOU 1-4 all go against my command and go to zero like they did? Its like the copter reduced the motor outputs on its own for some reason. The logged motor outputs match what I saw exactly, I switched to loiter and lost altitude, switched back and messed with throttle, got a bit of a climb, then it went down for good. If it was a downdraft shouldn’t the motors all gone to 100% to fight it?

After further investigation it looks like the copter cut the throttle and it started to fall. It then gave full throttle after it fell about 50% of the way down. Again it cut the throttle and just before it hit the ground it again gave it full throttle at which point it hit the ground. Don’t know what’s going on here.

This may have been a bug in 3.2.1. You should be running 3.3.3.


Thanks, I plan to update the SW after I get all the damage repaired. I was just nervous that if it isn’t a software bug what else the issue could be. I guess I’ll just fix it, update/calibrate, and do a lot of test flying before I put the camera back on.