Fail safe RTH

[stevearends]

Yesterday I was flying my Mavic 3 using the RC Pro. We live in the Colorado foothills. My flight began at my house and I flew up to the top of our property which was about 380 feet higher than where I took off. I took the M3 up to about 700 feet which was about 320 feet above the top of our property. I then began flying further into the mountains as the elevation increased an additional 200 feet so the M3 was approximately 120’ above the mountains and still 700 feet above my home point or takeoff point.

I had great signal and then all of a sudden I received a signal warning and when I looked at the RC Pro the signal indicator was red. I immediately pressed the RTH button and waited. It took close to 1 minute (I think) before I made contact with the M3 per the RC Pro. It came back directly above my head and I took over control and landed. Whew!!!!! Close call I think!

When reviewing the video I could clearly see the drone moving west right up to the point where M3 and RC Pro lost contact. The drone stopped moving, turned around and started heading towards me. I was about 1000 feet away. What I noticed next on the video was the M3 flew towards me (and home point) for about 5 to 10 seconds and then stopped. The video was still recording but no M3 movement for about 15 seconds, then all of a sudden the m3 began flying towards home again, and all was fine.

Does anyone have an idea why the M3 stopped returning to home for about 15 seconds?

 

[FLDave]

Get at the flight data .txt record file and upload to AirData. You should find your answer in the data. Learn to do this after every daily flights. It's a great learning experience and part of being a good pilot.

 

[Yorkshire_Pud]

As an alternative to airdata you could upload the flight log to DJI Flight Log Viewer | Phantom Help and then copy and paste the resulting URL here.
Slup or Meta4 etc. may be able to spot something.

Incidentally where was the sun, what was the cloud cover? I am wondering if the drone was perhaps flying into a visible sun and triggering an obstacle avoidance response.

 

[stevearends]

Great suggestions gentlemen! I’ll do both of those suggestions.

The drone was flying east - not into the sun. But, I can’t wait to see if the flight data reveals why the M3 stopped for 15 seconds after beginning its RTH.

Just thinking - if I were to try to go further west, further into the mountains with increased elevation, the only chance I’d have would be to increase the drone’s elevation so the controller and M3 could still “see” each other. And that could be tricky geometry. It might be alright if the RC Pro gave some kind of warning - “you have just entered into a positive where the line of sight is no longer there” but as I recall I went from full signal strength to “lost connection “ seemingly in a couple seconds.

Preliminary conclusion- “don’t fly behind a mountain if you want to avoid losing your M3”

 

[FLDave]

No need to wait for flight light information. Just get it off our your device and upload to your AirData account., You can do all the analysis yourself; it's great learning experience.

 

[Yorkshire_Pud]

No need to wait for flight light information. Just get it off our your device and upload to your AirData account., You can do all the analysis yourself; it's great learning experience.

All true and I would recommend learning to read them but a newbie learning to read a flight log could take hours of study to
a) understand what they are seeing and
b) dig out 'hidden' facts.

In a really obscure case I saw, I think, Slup use data from half a dozen or more different data channels to reach a conclusion. He was 'ferreting' in things that I doubt a newbie would have a clue about and I certainly didn't and I am not a newbie to logs, it was a jaw dropping analysis.

Besides, is you really want to learn to read logs Phantomhelp provides a much better csv of the flight log and you can process that using CsvView on your computer.

Yes, with these encrypted txt flight logs, there is some data that is available on airdata that is not, unfortunately, available on phantomhelp but overall I find Phantomhelp easier and better.

I have started to use both, airdata for the bits I can not get from Phantomhelp and Phantomhelp for all the rest,