I have been building and flying Radio Controlled Aircraft for 15 years.  My AMA (Academy of Model Aeronautics) number is 784057.  I am certified with the AMA as a Flight Instructor.  On August 30, 2016 I purchased a DJI Phantom 4 Drone for $1200.  I reviewed all manufacturer video tutorials.  I read the manual.  I registered this drone with the FAA (Registration FA3NY3HP3Y).  I completed all firmware upgrades.  I tested the unit and completely charged all batteries.  My wife and I wanted to take advantage of this units capabilities to shoot some videos of us on our boat.  Prior to our first flight, we made sure all telemetry was OK, battery levels were full, and that we had a GPS lock.  September 2, 2016 - On our first flight, we took off from the boat and had the drone follow us in "Active Track" mode.  Then I safely landed the drone back on the boat.  During this flight, my wife and I monitored all flight telemetry and video from the IPAD 4 Mini which was connected to the controller on board the boat.  All went very well.  Prior to our second flight, we insured that all telemetry was again OK.  Battery level on the controller was full and that on the drone was over 80%.  During the second flight, we again did some video in "Active Track".  All went well.  Then, while the drone was still in the air, I put the drone back in "Normal" mode and lowered it to a height about 100 ft off the water surface, and had it sit still.  We then did a few passes with the boat while the drone stood still.  Again, with my wife and I closely monitoring all flight telemetry on the IPAD.  During these passes, the telemetry alerted us that the drone went into "low battery" mode.  Immediately, we placed the boat directly underneath the drone.  After cancelling "Return to Home" and seeing on the IPAD controller screen that the drone acknowledged this command, I tried to manually bring the drone back to the boat.  I immediately noticed that, with every controller input that I attempted, the drone wanted to do the opposite.  In other words, when I manipulated the controller stick to have the unit lower in altitude, it would raise in altitude.  Similarly, when I manipulated the controller stick to have the unit go to the right, it would instead go to the left.  The unit kept fighting my inputs by going in an opposite direction.  So, try to imagine this - we are on low battery alert, positioned directly below the drone - normally it would take maybe 30 seconds for a seasoned pilot (like myself) to get this back to the boat.  However, with the unit constantly fighting my inputs, this ended up taking much longer.  After many repeated attempts to get the unit to follow my inputs, and with battery getting lower, I finally was able to slowly manipulate it toward the boat.  Unfortunately, by the time I got it close to the boat, it ran out of battery, the propellors stopped rotating, and the unit dropped immediately below to the water surface.  It then sunk to the bottom of the lake (September 2, 2016 at 1:03 pm).  I immediately noted the GPS location on my boats onboard GPS - N 45 21.468 and W 085 23.093.  Depth 165 feet.  I contacted DJI on September 2, 2016 at 2:44 PM at 818-235-0789 and talked to Joseph.  He then sent me an email on September 2, 2016 at 2:58 pm, in which I was instructed to provide DJI with pertinent information.  On Mon, Sep 05, 2016 08:50 PM I sent DJI an email with all of this information.  On Mon, Sep 05, 2016 09:45 PM, an individual named Florence sent me an email mentioning an RMA ticket and case number CAS-242374-F7N5T9.  Since then, I have been fighting DJI via email (sent email reminder Sept 9) and phone (Sept 12 three calls and Sept 14 one call) for resolution.  

FINALLY GOT A RESPONSE - HERE IS THEIR RESPONSE

The DJI GO app precisely records all the flight data, and we are able to reference the sync'd records to see what caused your aircraft to become lost.

You were flying over water, and the unit triggered return to home 16:46 minutes into the flight, when the battery was at 18%. The pilot then manually cancelled the Return to home at 17:31 minutes with 14% battery remaining.

The Phantom 4 then reached critical level of 10% at 18:38 minutes and the auto landing feature was triggered, which cannot be cancelled. Then, the unit landed in water. With this finding, it is a non-warranty and determined as pilot error.

MY RESPONSE TO THAT - However, between 1731 and 1838 after cancelling return to home I kept fighting the unit to get it back to the boat and that is why it ran out of battery  before I could safely land.  Unit was fighting my inputs during this time.  Not pilot failure but rather failure of unit to respond to manual inputs.  Is it possible that firmware glitch has the unit always wanting to return to home when in low battery mode?  However, as you know, in case of on a boat, return to home MUST be done manually because previous HOME no longer exists because I am on a moving boat ?

This is unacceptable.  I am a seasoned aircraft pilot.  The unit had a failure in flight.  My wife can also attest to this.  I ask for your help in this matter.  Thank you so much in advance.  Sincerely  Michael Roe

Hi, the main issue here is whether the drone answered to your command input in an opposite direction, and if we can prove this.

Do you have another DJI drone that you test the RC?   Did you send in the RC? If you send in the RC, and our repair center can replicate the issue(reverse input), the decision can be reconsidered.

Anyway, I've escalated your case and my colleague will contact you within a day or two to offer you a solution.

Hello Michael, would you mind providing your DJI account (like e-mail address), we will help you double check it.

harleymon6969@netzero.net

Spoke with marshall today here is where we are at

I ask you to please to note the final flight at time 18:10. Altitude is 13.1 feet. Please note how many times the left stick goes DOWN, yet the altitude does not lower AT ALL.

You can see that I lowered the left stick several times but altitude stayed at 13.1 feet, and then finally at 18:34 (after repeated DOWN commands) to 9.8 feet.

So, for 24 seconds I was repeatedly wanting DOWN but unit did not respond.

This is all BEFORE critical battery kicked in and unit went into auto land.

Please explain why these DOWN altitude commands inputted on controller from 18:10 to 18:38 did not result in lowering the altitude of the unit more than this ???

Thanks Mike

From 18:10 to 18:16, when you pushed the left stick down, the altitude reduced from 5m to 4m. And the altitude measured by ultrasonic reduced from 3.7m to 3.0m. At 18:31 , the altitude reduced to 1.9m. The aircraft was performing as expected. The battery then reached critical level (10%) at 18:38 minutes, and the auto landing was initiated, which cannot be cancelled. Then, the unit landed in water.It's determined as pilot error.Thans for your understanding.

The issue voiced here was not the reversal of the left stick but the right. I have experienced it a few times on my p3a, once on a low battery, and once just recently... I believe the issue is that when you add inputs and there's wind present, the drone first sort of gets a bit lose on holding gps and lets you take control, but if you do not push it enough, it will drift with the wind slightly and make it seem that perhaps the controls are inverted.. That is a possibility I agreed to live with on my drone, because DJI would not look into that side of it, even though the logs contain the position of the right stick as well as which direction the drone was moving.
I have not lost or crashed mine, but if someone did, like the OP, I would say, PLEASE DJI, look at the right stick movements in the logs, and compare to the actual responses from the aircraft, and confirm that the user is incorrect...  however if the user's experience IS indeed confirmed by the logs, then you got something that perhaps is a bug in both p3 and p4 in certain conditions?
I have experienced similar behavior in autolanding mode... is it possible that autolanding does something weird, as opposed to just return home?

Thanks but was no wind at all.

That's interesting  that DJI says altitude decreased during these 24 seconds but yet my flight log says it did not.

I am through fighting with DJI - I guess you win

I purchased another unit.

Do a lot of testing in similar conditions (not over water). Also, what makes you think there was no wind at altitude, esp. over water? But still, not that you have a new "baby" make sure you test same scenario during RTH as well as AutoLanding, make sure you are all comfortable....