Phantom 4 Pro Ver2 fell from sky into river and unrecovered

Hello all,

I am not sure if I posted this in the correct section or not, so Admins please move if necessary.

We were using one of our Phantom 4Pro, ver2 today over the river conducting a survey for manatees here in Florida for a new research study we are starting.

The first flight went fine but the aircraft seemed to be acting somewhat lethargic, like it was in tripod mode where movements are slower, it wasn’t however. There also seemed to be a fair delay in the drone receiving and responding to control commands, but no errors appeared.

At the start of flight two, there was an IMU calibration error, I shut everything down and restarted away from the boat’s motors and batteries in the read of the boat and everything seemed fine. We did have a vision sensor stating that it needed to be calibrated, but we were not flying around anything to hit over open water and could easily just turn these off if needed.

We launched the drone and the video video was really broken, we took it up to survey altitude (80m) and it kept going to max altitude at ~120m controls started being non-responsive. I tried to shut the down and restart the controller and while it was re-booting the drone fell from 100m and smacked the water. The flight log for this flight is:

I don’t see any issues at first glance and any help is greatly appreciated in better understanding what happened.

We have liability and hull insurance and have never had to make a claim so I am not sure how that is going to go without an aircraft, but we’ll see.

The only other thing to add is we had a small Lidar altimeter and GPS setup that was independent of the drone (essentially a small acrylic frame with components mounted with zip ties to two of the Phantom’s legs). We have never had any issues with it interfering with the drone or flights in the past, but that is another $500 piece of equipment that now needs replacing.

Very frustrating…any help is greatly appreciated.

Jamison Smith
Blue World Research Institute