I was out flying yesterday in good conditions with my Phantom 4 in "ATTI" mode hovering in a stable state at a height of 40m and a distance of about 60m. After about 30 seconds in this position and without any control input from me the drone quickly yawed right about 90 degrees and started flying away from me into wind, and then changing direction and flying downwind towards me. There was no particular height deviation during this.
The P4 didn't appear responsive to the controls at this stage so I switched back to "P" mode which didn't seem to make any difference either. I then pressed the RTH button at which point normal service was resumed, which was fortunate as I was about to cut the motors!

A subsequent 5-minute flight, again in ATTI mode, was flown without any gltiches.

Any ideas what could cause this loss of control? My first thought was interference (it looked similar to my old 35Mhz r/c glider days when someone was on the same frequency) because the uncommanded attitude changes were so definite, rather than random oscillations.

Thanks!

It could be that that there was interference to the signal, or perhaps even seen as 'loss of signal' by the aircraft, at which point it would have initiated a return to home. You pressing the return to home button again cancelled this and gave you full control again.

Just a thought

Thanks for that, but I was flying in wide open parkland with no obstructions. Clear skies, and a light wind (8mph).

I hadn't considered the Phantom going into RTH mode by itself. However, the track from loss of control point doesn't look as "tidy" as a RTH track would be, and in fact when I eventually baled out and pressed the RTH button and the drone started to come back to me, the track to the home point is dead-straight as you'd expect.

The mystery continues!

We're you using auto or manual channel

Auto I think - is that the default setting? I haven't changed that setting but will check again. Thanks!

Just as a thought you could post the flight record into https://healthydrones.com/ and get a better view of what may have caused this.

And perhaps post the results for others to have a look at.

I'll do that - already a member, it's an excellent site/service! Many thanks,

Paul

paulharmer Posted at 2016-5-1 04:32
Thanks for that, but I was flying in wide open parkland with no obstructions. Clear skies, and a lig ...

Your lucky. The same thing happened to me in P mode a few days ago, except I wasnt able to recover control before my P4 crashed. I sent in my flight logs for DJI to analyze and all they said was they recommended I send it in for repair, but didnt mention what could have gone wrong.

With luck they'll come back to you with a reason? Disconcertion not knowing why something's gone wrong. I've posted my flight onto the HealthyDrones forum although I think it's awaiting moderation at the moment. I suppose there's always some risk with so much technology (at a relatively low cost) so it becomes even more important to fly safe!

paulharmer Posted at 2016-5-2 12:42
With luck they'll come back to you with a reason? Disconcertion not knowing why something's gone wro ...

Can we see the healthy drones report ? it allows you to share that flight with others, and you can select which details to show to protect personal information.

Yes, sorry for the delay!

http://healthydrones.com/main?share=KPmYMk

Paul