P3 Pro got a mind of its own

[Encran]

So I will talk you all through this issue. I would be interested to find out if many people have had the same or similar issues with the P3 pro or P3 series aircraft.

Wind speed on the day was less than, or equal too 5kph mostly still and settled and there was no rain.
Battery was full on takeoff and the aircraft flew normally throughout the mission. Our mission parameters as filed with the Irish Aviation Authority where that the aircraft would takeoff from point A, fly to point B and then onward to point C for landing and battery swap if required. On approach to LZ (point C) at 29% battery the aircraft tried to initiate RTH which I canceled as the aircraft was landing at point C NOT point A. As I was on approach the battery dropped to 27% ~70m away from the LZ. So still plenty of power. Then without warning the video image went grey, telemetry and control signals dropped all at the same time. Personnel present at the LZ stated "I saw it on approach it then seemed to halt for a second and drifted around for a few seconds before flying off eastwards". The P3 was not recovered and the area was canvassed.

I contacted DJI support and submitted my logs as they requested, this was their response:
1. Aircraft worked at GPS mode;
2. T=14-28, h=4m, d=728m, 29% battery power, RTH was triggered due to low battery; T=14-32, pilot cancelled the RTH and flew the aircraft more far away from home point by pushing pitch stick forward；
3. T=15-13, h=5m, d=1032m, the record stopped while the aircraft was flying forward. At the end the aircraft would not have enough battery power to return home.
According to the analysis, the incident was not caused by any product malfunction factors. As such, we could not provide warranty service.

DJI stated there was no malfunction, but in the same email they stated that "the record stopped while the aircraft was flying forward" How can the flight recorder stop mid flight? Doesn't it continue until landed and motors powered down? Has anyone else had all transmission signals from their aircraft just drop simultaneously and lead to loss of the aircraft? They have stated this is not a warranty case as their was no malfunction when there must have been. Any advice or stories similar to mine would be appreciated guys.

 

[Pharm]

The recording stopped when you lost contact. It can only record what's transmitted to the receiver. When contact was lost, no more info was transmitted to the RC/your device. HOWEVER, more detailed info is recorded on the Phantom itself and the recording should include everything until the end of the flight (landing/crash, etc.). If you can find the bird, you can retrieve that info from it. If you can post the logs that you have, one of the geniuses of flight analysis here will give you their take on it.

Follow the instructions here:
DJI Flight Log Viewer

After uploading, post a link back here.

 

[Meta4]

3. T=15-13, h=5m, d=1032m, the record stopped while the aircraft was flying forward. At the end the aircraft would not have enough battery power to return home.
According to the analysis, the incident was not caused by any product malfunction factors. As such, we could not provide warranty service.

It sounds like you flew a long way from home and didn't reset the home point.
So your Phantom wanted to get back home before it's battery level was too low to return.
We'd need to see the flight data to be able to offer useful comment on an incident like this.
Go to DJI Flight Log Viewer
Follow the instructions to upload your flight record.
Come back and post a link to the report it provides

 

[ryantrax]

Welcome to Phantom Pilots, I'm sorry for your loss.

 

[Encran]

Yes the aircraft was not recovered lads, it was 1km from takeoff point but was only 70 meters from the landing point. As stated the takeoff point and landing point where not in the same location. Besides that it was witnessed flying off in an easterly direction of its own accord. So even if the statement RE the RTH function was correct then the RTH would have made the aircraft fly in a SW direction to return home instead it flew off in to the east.
We are not dummies either, I am flying SUA's for nearly 11 years and have nearly 500 hours logged in a professional capacity with our much larger 6, 8 and 8 axial setups. I am am more interested in finding out if other DJI customers have had simultaneous VTX, Control and telemetry loss.

 

[Encran]

All that said with 27% battery and no headwind the aircraft would have been able to cover 1,083m to land at the takeoff point as the RTH altitude is never set above 50m as I only fly open field and the aircraft would not have had to expend much of the 27% in climbing to that altitude, I have calculated that there should be 8% left in the battery on landing as the aircraft would not have had to combat headwind. But as I said it was being landed 70m away from the point that the transmission was lost.
Do DJI have me by the balls because the drone was not recovered? If so that should be a cautionary tale. Murphys law too as the P3 was the only SUA in our fleet without a locator tag -.- go figure.

Oh and thanks Ryantrax for the welcome and the condolences (for lack of a better word)

 

[Meta4]

All that said with 27% battery and no headwind the aircraft would have been able to cover 1,083m to land at the takeoff point as the RTH altitude is never set above 50m as I only fly open field and the aircraft would not have had to expend much of the 27% in climbing to that altitude, I have calculated that there should be 8% left in the battery on landing as the aircraft would not have had to combat headwind. But as I said it was being landed 70m away from the point that the transmission was lost.
Do DJI have me by the balls because the drone was not recovered? If so that should be a cautionary tale.

DJI frequently replace drones that have been lost, as long as the flight data shows that the loss was due to a DJI issue.
DJI are telling you that the flight data indicates that the loss was due to what you did - not a problem or malfunction in the Phantom.
You haven't supplied flight data so we can't tell if DJI got it right.
The flight data often shows a lot more than Airdata so it would be good to see and might shed some light on what happened with the RTH.

With no headwind, your Phantom won't RTH and still be flying at 8%.
It would have autolanded before that and if it was fighting a headwind that could have happened anywhere.