The flight log video shows a sudden drop in altitude and does not show any sudden drop in the throttle - it remains very close to the neutral position - the phantom should have maintained altitude. Even if he was incompetent and accidentally put the throttle all the way down, the phantom still wouldn't have crashed into the water if it was functioning correctly; it descends at around 1m / s and would have taken 3 seconds to hit the water.
All you people shouting "pilot error!" are choosing to ignore the altitude data and exaggerate throttle data.
In any incident investigation you have to work out what evidence can be relied on and what is potentially unreliable.
The recorded flight data has been proved reliable hundreds of times.
Eyewitness accounts on the other hand, can be affected by confusion, misunderstanding and even deception and where they contradict the recorded data, I would accept the data almost every time.
We seen few posts like yours lately suggesting that the data could be inaccurate but none have ever shown an example of faulty flight data to support their claim.
Just an assertion that it
might be faulty.
You are completely ignoring the relevant data and your faith in the accuracy of barometer for altitude recording is misplaced.
It is
very common for the altitude shown by the barometric sensor to be out by a few metres from the start of a flight to the end due to heating up during the flight and possible small changes in air pressure during that time.
The absolute height shown by the barometer cannot be relied on but the trend can.
The assumption that his Phantom was 29 feet above the water because the barometer indicates 29 ft is likely to be in error.
Even the OP didn't claim that his Phantom fell 29 feet into the water. His guesstimate was 8 feet.
The data shows the left stick pulled down to an average position of 843 from 7:16.1 and still in that position when the flight record ends.
This is matched by a steady descent from an indicated altitude of 51.5 ft until the end of the flight record at 7:22.7 when it shows 28.5 ft.
Over this time the rate of descent has varied between 3-5 feet per second.
Now if you are flying at 40+ mph just a few feet above the water and descending at 3-5 ft per second .... what do you suppose is the most likely outcome?
The claims about it being risky to fly at 9 feet in Sport Mode are rubbish. Yes, the drone tilts forward - and thrust is automatically increased to cope - this is what a flight computer does. I have flown my drone low and fast plenty of times.
Flying close to obstacles (the ground is an obstacle) is risky at any time.
Flying close to obstacles at 40 mph is very much more risky.and many times more risky at 40 mph.
Continue to enjoy your risky flying. Pay attention to how well your Phantom maintains altitude in sport mode and what it does when you ease off the sticks.
Finally, I myself have also witnessed the phantom 4 descending uncontrollable when in return to home mode, not properly responding to user input. I nearly lost mine right before my eyes in the river like this - and no it was not pilot error - it was something to do with RTH mode.
Something to do with RTH mode is extremely vague and explains nothing.
If you want to learn from the incident to help you avoid it in future, it would benefit you to investigate the actual flight data to find out what really happened.
In any case DJI's job is to create a predictable, reliable drone that is easy to fly. If they can't do that then they better find something else to do - because that's what their whole business is built on.
Do you have any reason to believe that DJI aren't producing predictable, reliable drones that are easy to fly?
From my experience, Id say that is exactly what they do and that they do it very well.
Dismissing your fellow flyers on the forum as incompetent to elevate your own self esteem as a gifted pilot instead of listening to them is dumb. Try being kind and offering support instead.
There are only a few members here that analyse flight data and if that's what you think they do, you've not read many of their incident reports.
Sometimes they are able to show that the cause of an incident was a malfunction and advise the pilot to help them in dealing with DJI, sometimes not.
But the result is always of great educational benefit to all pilots that want to learn from unfortunate flight incidents and prevent repeating them in the future.
That's offering real support.