LOITER mode descent into the ground

Hello Folks,

I have a V frame quad with a 3DR Pixhawk and 3DR GPS/compass. I’ve been flying it for quite some time and it’s a good reliable quad. Yesterday there was an event that I haven’t seen before whereby the quad started a continual descent into the ground when I put it into LOITER mode.

I’ve had a look at the dataflash logs and there are no reported errors throughout the entire duration of the flight. The event happens between line 16(^3) and 17 on the log screenshots, after the activation of LOITER mode. After striking the ground at a relatively high rate (fortunately no damage, it was soft grass) I went back to STABILIZE and it continued to fly normally once again.

Vibration levels up to and including the impact (big spike): i.imgur.com/jUgdW19.png
I believe these to be pretty low and within recommended limits?

Baro altitude versus Desired altitude during the LOITER: i.imgur.com/XwRUYIq.png

Throttle in versus Throttle out during the: i.imgur.com/IFnJxoW.png
I increase the throttle towards 100% on my transmitter to try and stop the descent but there is no response.

BARO Alt, HDOP and Number of Sats: i.imgur.com/BXPwz2c.png
That is Alt from the BARO section of the logs, and HDOP/Sat count appears normal and healthy throughout the LOITER.

Vcc: i.imgur.com/PaHtrLi.png
Remains like this throughout the entire flight, only very small variations seen.

It did LOITERs before and after this one and they were all fine. Only this particular LOITER was behaving differently. I can provide more information to help diagnose if required. I’m a little stuck as to what has caused this descent.

Thanks very much!

1 Like

Adding a note that it’s running v3.2.1

If possible, please attach the full logfile of the flight.


I’ll try to get you the log file when I’m next at that PC.


Same issue here. Any solution?