Althold altitude change then crash

Went flying today and noticed that poshold was very unstable and that the drone would not hold but would rather do a big circle.

Switched to Althold mode and brought it in to land. About 5 meters above the ground the drone started oscillating side ways and flipped on its head.

File attached. Probably the 7th crash like this with this Navio2
log_7_2018-7-5-17-18-46.bin (2.9 MB)

Hi Barry,

Could you please answer a few questions?

  1. Was Navio2 powered when the drone flipped?

  2. Which model of RC transmitter and receiver do you use? Do you have a Mode 1 or Mode 2 transmitter?

  3. When did compass calibration take place - before the flight in the field or earlier indoors?

Hello Tatiana.

Drone was flying at the time

TX = tararnis Q7 RX= TBS crossfire 8 channel

Before the flight

log_1_2018-7-7-16-42-36.bin (548.4 KB)


Please let me know if you can help me sort this out. If you are unable I would like to return both my navio2 thanks you


To provide support on your issue we’ll need more info. Now it’s impossible to say why it happened.

  1. Did you notice what was the LED color on Navio2 just after the incident?

  2. Have you seen the drone at the moment it started falling? Did it look like the drone was switched off before it?

  3. Could you please also share:

  • your GCS logs;
  • images of hardware Navio2 setup;
  • the list of all connected to Navio equipment?

Please check your wiring and connectors. Now it looks like a powering issue.


Thank you for answering

The log is posted above

No i cant see what the led looked like it was flying

I 4 esc’s connected as well as the radio receiver


Could you please post the telemetry log of your Ground Control Station?

Also, it will be great to see the photo of your Navio2 to drone mounting.

What about the Navio2 LED color just after the falling, at the moment you’ve found it laying on the ground? Have you noticed it?

Have you checked all wires and connectors?

Hello Tatiana.

No i did not notice the LED jsut after the crash

Look at the post just above the picture. That is the log.

I am rebuilding the drone and will send photos once it is completed.

Hello Barry
I analyzed logs and I did not find any errors. However, both logs suddenly interrupt. It is possible the drone has a problem with the power supply or there was a log writing error. As you understand, log writing error can’t lead to a crash. Actually, if there was a log writing error, you would see the error in the Ground Station.
I’ve also noticed that in the logs end the drone committed abrupt short-term incline. This maneuver could provoke a power failure if some wires were damaged, poorly fixed or connectors were worn out.
Have you been using Mission Planner while the drone crashed?

Hello Alexsandr.

I think you might be on to something with the power. I am completely rebuilding the drone in an effort to sort that out.

What I did notice that in the Raspberyr pi POST there were a couple of “Low voltage” warnings when using the NAVIO2 power module. I will use a ubec on the servo rails as well to see if this goes away.

I use Qground control for my ground station. The only warning i got was NO IO heartbeat or something like that. I did not get any LOG errors.

I am perplexed by the sharp incline as the drone was hovering level. Might it not be that the sharp incline that you see is the beginning of the drone going out of control?

Try to find log files here: \users\ @username@ \Documents\QGroundControl\Telemetry

I download them directly via qground

I was wondering if it is possible that the usb dongle I am using for wifi can draw to much power and cause and under voltage situation that can cause the unit to crash?

Yes it’s possible if you use too powerful USB WiFi on Navio2 for example.

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