No signal then drown at sea

[GadgetGuy]

That's just what happens when you don't stop recording before powering down.
The file doesn't get closed off properly and have an end of file marker.

Is that file recoverable? If so, what is the procedure? I have one created during a forced landing while the battery was dying, and was unable to stop the video before signal was lost, as it landed below my LOS. By the time I got there, the battery had shut off. There is a 700MB file that won't play. I thought that by putting in a fresh battery that it would close it properly, but the file still won't play, and the .SRT file is 0 bytes.

 

[GadgetGuy]

The Phantom never lost signal as is shown by the app recording the whole incident.
As signal was never lost, RTH was not activated automatically.
There are two signals.
1. Video downlink
2. Control signal
You may have lost the video downlink and believed this meant you had lost signal but the control signal doesn't get lost as easily and you still had full control as well as the app receiving telemetry.

Unfortunately, the red Signal Lost message in the P3P app is ambiguous, and doesn't clearly spell out that it is only the video downlink that is lost, and not the control signal. I got bitten by that early on. The key I learned is to always check the control signal on the RC. Unless it is red, as long as it is still green, you are still in full RC control of the aircraft, and the RC is still connected. With the P3P, the video downlink is always lost before the control signal. Just elevate the aircraft with the left stick on the RC to restore the video signal, and sally forth!

 

[hoctro]

Unfortunately, the red Signal Lost message in the P3P app is ambiguous, and doesn't clearly spell out that it is only the video downlink that is lost, and not the control signal. I got bitten by that early on. The key I learned is to always check the control signal on the RC. Unless it is red, as long as it is still green, you are still in full RC control of the aircraft, and the RC is still connected. With the P3P, the video downlink is always lost before the control signal. Just elevate the aircraft with the left stick on the RC to restore the video signal, and sally forth!

Sorry for the late response: yes it was RED during the last 2 minutes as I had mentioned briefly "but the red light was still there on the RC". I know that Meta4 was trying to recreate the "crime scene" from the flight log while I had to handle the situation with what I saw at that time: an unresponsive Go app screen and a red light on the RC. However the flight log did not back me up.
Could we try this scenario: - manual take off for 10 seconds then grab the Aircraft, power down the battery. This should make the green light turn red and the flight log should record some messages about disconnection. It's not really similar to my incident (as my battery was still on) but it duplicates the red light issue.
I know I owe Meta4 and msinger a round of beers: their time, dedication, expertise and willingness to help all members. Now my new headache: should I grab the refurbished $599 P3P or get in line with the $999 Mavic? I still have 1 additional P3P battery but the compact size of the Mavic is so tempting...

 

[hoctro]

The Phantom never lost signal as is shown by the app recording the whole incident.
As signal was never lost, RTH was not activated automatically.
There are two signals.
1. Video downlink
2. Control signal
You may have lost the video downlink and believed this meant you had lost signal but the control signal doesn't get lost as easily and you still had full control as well as the app receiving telemetry.

I appreciate your explanation and I understand it. However I believe the RC LED should have stayed green when the video downlink was lost. In my case, it was red in mid flight and there was no alarming beep. It was unfortunate for me that the flight log did not capture this issue.

 

[GadgetGuy]

Sorry for the late response: yes it was RED during the last 2 minutes as I had mentioned briefly "but the red light was still there on the RC". I know that Meta4 was trying to recreate the "crime scene" from the flight log while I had to handle the situation with what I saw at that time: an unresponsive Go app screen and a red light on the RC. However the flight log did not back me up.
Could we try this scenario: - manual take off for 10 seconds then grab the Aircraft, power down the battery. This should make the green light turn red and the flight log should record some messages about disconnection. It's not really similar to my incident (as my battery was still on) but it duplicates the red light issue.
I know I owe Meta4 and msinger a round of beers: their time, dedication, expertise and willingness to help all members. Now my new headache: should I grab the refurbished $599 P3P or get in line with the $999 Mavic? I still have 1 additional P3P battery but the compact size of the Mavic is so tempting...

There's a third option in the middle, available today: a DJI refurbished P4 (unit was returned within 7 days of purchase so it cannot be resold as new, and was then verified by DJI to be fully working as new, with the same 1 year warranty as new) for $799 from DroneNerds.com

 

[ElGuapo]

hoctro - For future reference or others in this forum. When I had my P3P I had the same identical issue you are describing with the RC.
Compass and IMU calibration is a temporary (band aid) fix to the issue. The long term solution is to Link the RC to the Aircraft as per users manual, even though it think it is already linked. Do not ask me why this has to be done but I found it to be the only fix.

The first time this happened to me the aircraft was flying like a charm, landed to switch to a fully charged battery. When I re-started the aircraft the issue came up. After fiddling with this for a few days I found that the only fix was to Link the RC to the AC, after that the problem went away for good until I sold the P3P for a P4.

You may want to contact DJI regarding this incident, they may be able to help with a discount on a refurbished unit or repairs. I HAD THIS HAPPENED TO ME, luckily it was otherwise inconsequential. No where in the user's manual it tells you that you have to Link the RC to AC to get rid of this issue. In fact if you read the manual it clearly states

I am sure that if you had known this, you would have followed the proper procedure to link the RC to the AC and you would not have dipped the bird in the ocean.