Almost lost the P4A

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Hi,
I was in a mapping mission using Map Pilot.
Suddenly the drone switched to ATTI mode and it was carried away by the wind. In my "panic" i pressed RTH but nothing happened.
Then I closed MapPilot and opened DJI GO 4. In DJI GO i saw some compass error and the drone was in ATTI mode. The side switch did nothing to bring it to P-Mode or Sport mode.
Thankfully I managed to bring it back manually and landed it safely.
I am licenced pilot in my country (Greece) and thankfully I had the training to overcome the situation.
I attach the Map Pilot log if anyone can help analyze the cause of the problem.
I attach also the dat file from the ipad.
 

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  • DJIFlightRecord_2021-03-06_[14-14-24].txt
    585.8 KB · Views: 23
  • 2021-03-06_14-20-12_FLY126.DAT
    1 MB · Views: 12
Last edited:

Meta4

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Hi,
I was in a mapping mission using Map Pilot.
Suddenly the drone switched to ATTI mode and it was carried away by the wind. In my "panic" i pressed RTH but nothing happened.
Then I closed MapPilot and opened DJI GO 4. In DJI GO i saw some compass error and the drone was in ATTI mode. The side switch did nothing to bring it to P-Mode or Sport mode.
Thankfully I managed to bring it back manually and landed it safely.
I am licenced pilot in my country (Greece) and thankfully I had the training to overcome the situation.
I attach the Map Pilot log if anyone can help analyze the cause of the problem.
I attach also the dat file from the ipad.
Here's what that flight data looks like:

Launching from reinforced concrete can cause a yaw error and uncontrollable flight.
But this wasn't what caused your incident.
A yaw error usually results in the drone zipping off at very high speed in a curved path.

Your Phantom completely lost GPS reception and was left in atti mode.
This left it hovering in the air and still controllable, but unable to RTH as it had no way to find the home point.

The reason for losing GPS is a mystery.
1. It could be as simple as a loose antenna connection or a hardware failure.
2. Or I've seen a few cases of GPS jamming which blocked GPS signal.

Does the Phantom receive satellite signals now?
If it does and if it works properly from now on, it was a one-off incident and possibly #2.
If the drone won't pick up GPS signals anywhere now, then #1 is probably the cause.
 
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Thanks for the reply Meta.
After the incident I went to another site and powered up the drone to see if it works.
It received satellite signals and there was no error in dji go but I didn't fly the drone because I hadn't the time.
The second file i attached (.dat) must be the log after opening DJI GO but I don't know how to analyze it. Can anyone check it for me?
Generally that day I had also issues with my other gnss equipment (I am a surveyor) and had difficulty maintaining a fix although the site was clear of tall trees etc.
In Map Pilot I had designed 2-3 mission alternatives of the site and had some trouble executing them but I thought it was some bug from Map Pilot because of lots of waypoints.
The first 3 efforts went wrong and had to bring the drone back.
The fourth-fifth effort (two battery mission) went fine.
The sixth effort was a mission perpendicular to the first to gather more photos but this mission went totally wrong.
Anyway I looked at the other logs from the first efforts and it also showed some "GPS Position not match" error.
effort 1 DJI Flight Log Viewer - PhantomHelp.com
effort 2 DJI Flight Log Viewer - PhantomHelp.com
effort 3 DJI Flight Log Viewer - PhantomHelp.com
effort 4 DJI Flight Log Viewer - PhantomHelp.com
effort 5 DJI Flight Log Viewer - PhantomHelp.com
effort 6 DJI Flight Log Viewer - PhantomHelp.com
 

Meta4

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Anyway I looked at the other logs from the first efforts and it also showed some "GPS Position not match" error.
effort 1 DJI Flight Log Viewer - PhantomHelp.com
effort 2 DJI Flight Log Viewer - PhantomHelp.com
effort 3 DJI Flight Log Viewer - PhantomHelp.com
effort 4 DJI Flight Log Viewer - PhantomHelp.com
effort 5 DJI Flight Log Viewer - PhantomHelp.com
effort 6 DJI Flight Log Viewer - PhantomHelp.com
There were some real interruptions to GPS that day.

1st flight, at 11 seconds, GPS dropped to zero for 22 seconds with a further 5 sec before GPS quality was good enough.

2nd flight, at 0:46 the number of sats dropped from 14 to zero for half a second, but it took 5 seconds more before the flight controller would accept the GPS data.
There were lots of GPS Position NoMatch messages while this was happening.

3rd flight had a similar event that went for 10 seconds
4th flight - no problems
5th flight - no problems
6th flight - GPS lost for the last minute of the flight
 
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No. I was at clear site.
The problems with my other gnss equipment makes me wonder if that day something was not good with the gnss signals but I can't confirm if this is the problem.
I must perform some more flights to check if the gps on the drone has malfunctioned.
 

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