Litchi Flight Phantom 4 A Did Not Return

[CharlieU]

I lost my Phantom 4 Advanced. I know it was a many rules broken Litchi mission. Mission Hub - Litchi
I flew the mission with one P4A without incident. I wasn't satisfied with the video so I returned to the takeoff point with my second P4A. I kept losing connection which I did not on the previous flight. At 2:46 sec into the flight I hear "mission ended". I begin trying up stick, RTH. Connection comes in and out. Viewing the data I see the aircraft went crazy and left the flight plan veering 100 ft toward an electric utility transfer facility, At the 4:00 mark it goes into Auto Landing. Driving to the last known position I tried to pickup a signal. I searched the area but no drone. The probable landing spot was 50 ft. from a road with lots of nighttime traffic. I think someone grabbed it before I got there. Any ideas what happened? As far as the lost drone goes I will chalk it up as a learning experience for taking risky flights. Yes my reg and Phone # were on it. DJI Flight Log Viewer - PhantomHelp.com
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Good news. Eight days after the Phantom 4A was lost I got a call from a resident who found it in his back yard. The aircraft continued on another 1700 ft from where the data showed it quit. It crashed with broken props and gimbal damage. Repair invoice was $1231. More good news, DJI covered under warranty. I received a replacement today Nov. 21st which looks like a new drone. I thank you all for your help. Below is a link to the video. Stalls at 2:52, goes crazy at 5:24. It obviously had some serious problems before it crashed. P4A Crash 11-2-2019.mp4

 

[Fly Dawg]

I begin trying up stick, RTH. Connection comes in and out. Viewing the data I see the aircraft went crazy and left the flight plan veering 100 ft toward an electric utility transfer facility, At the 4:00 mark it goes into Auto Landing.

You had many issues far before that. I can tell you why the mission ended. At ~166 seconds your sat count went to zero. The mission will end there. You had in and out control for most of the remaining time, although the sat counts never returned after ~190 seconds, thusly putting the aircraft in ATTI mode.

 

[Fly Dawg]

Your last position was here and probably already on the ground. Awfully close to that power sub-station.

 

[RodPad]

Using Street view, looks like you would need a ladder or another bird to see if it is behind the wall, if it is you already got your personal information on it.

Rod

Added: Were you using Litchis screen recorder?

 

[CharlieU]

Using Street view, looks like you would need a ladder or another bird to see if it is behind the wall, if it is you already got your personal information on it.

Rod

Added: Were you using Litchis screen recorder?

Did not use screen recorder. Searched area and over wall with P4 at sub-station. Nada.

 

[Fly Dawg]

Looking at the last 30 seconds or so of data, you were issuing elevator and aileron, and traveling ( apparently ) in a northeasterly direction before the data ends. It is possible that the altitude was off and you continued in to the road. You probably didn't get much farther than that.

 

[CharlieU]

You had many issues far before that. I can tell you why the mission ended. At ~166 seconds your sat count went to zero. The mission will end there. You had in and out control for most of the remaining time, although the sat counts never returned after ~190 seconds, thusly putting the aircraft in ATTI mode.

View attachment 115405

Any idea why satellite count would suddenly go from 16 to zero? Do you think I might have saved it if I went to sport mode?

 

[CharlieU]

Looking at the last 30 seconds or so of data, you were issuing elevator and aileron, and traveling ( apparently ) in a northeasterly direction before the data ends. It is possible that the altitude was off and you continued in to the road. You probably didn't get much farther than that.

View attachment 115408

I checked the road about 20 minutes after takeoff. The road and both sides were well light up.

 

[THE WARRIK]

I just read a post about someone having the satellites all cut out while running a mapping route...sorry I just spent the last half hour looking for the post and cannot find it

 

[Fly Dawg]

Do you think I might have saved it if I went to sport mode?

No. Loss of GPS results in ATTI automatically. There is no positioning in ATTI Mode. Only the barometer for altitude hold and VPS. That's it. Everything else is manual.

 

[Rick26h]

Sorry to hear about your loss, my P4P developed the same symptoms with GPS loss for no reason using Litchi. I like to use Litchi because of the audio updates which I set at 10 sec intervals, hovering over a fire scene, I watch every move my UAV makes vs watching a screen. Several times I heard 0 satellites and my unit began drifting away in ATTI mode. I grounded the UAV and sent it down to Drone Nerds for evaluation and repair, GPS board bad. My Inspire One did the same thing using Litchi at a fire scene, heard the warning 0 Sats, and off to the races my UAV went in a 20 knot wind carrying my $2000 Flir Vue Pro with it. A little hard to do my job properly now after these situations, I sit on pins and needles and stare at my UAV's for any unauthorized movement when hovering over a fire scene now.
I was able to grab control of my Inspire One and land it safely next to me, of course I grounded that UAV as well and sent it down to Drone Nerds. Not sure why mine or others have had this type failure, just the luck of the draw, it is electronics, and electronics fail when you don't expect it, knowing how to recover your UAV when this happens is the key, flying within sight when possible may help.

 

[THE WARRIK]

I found the other thread...drone deploy also discusses a similar issue

 

[RodPad]

I was looking for a thread myself, I couldn't find it.
You got a link?

Rod

 

[THE WARRIK]

The thread I am referring to is called "Drone Deploy" in the mapping section and the reference post is by "Harleydude" on the second page...It sounds a lot like what happened here...

 

[Andy9]

How could be the path plotted on the map if all satellites had gone?

 

[Fly Dawg]

How could be the path plotted on the map if all satellites had gone?

You need to look a bit closer. They dropped out near the end of the flight path. It is possible that the FC was recieving the positioning data but very erratically. Unfortunately, Litchi's data files are very limited in comparison.

 

[T Dogg]

Had a similar problem. I flew a few Litchi 'Orbit' missions last week with my P4P to do a timelapse/hyperlapse video and photos (experimenting with litchi to do repeat missions) of a construction site which turned out great. Planning on doing one flight per week.

Tried doing the exact same orbit missions yesterday. The first two video flights went well but when I loaded and started the third mission I hadn't set the Interval setting for the photos so tried to cancel the mission to restart it...

The app wouldn't respond although I could stop taking photos and record video etc...couldn't cancel mission in the app.

Hit RTH button on remote which started bleeping but the drone stayed flying on the Orbit mission...heartbeat rising slightly...turned the controller to Sport mode and back which last week would stop the mission...

Not this time...getting a bit panicky but remained calm. Had about 50% battery left. Restarted Litchi now saying NOT CONNECTED but drone still doing Orbit mission...WTF.

Started DJI Go4 app while Litchi was running but Go4 saying disconnected. Closed both apps and reopened DJI Go4, still no connection...Heart rate rising at this point!!! Restarted Litchi...

Tried RTH again still no good although remote bleeping, next low battery bleeping as well at 30% and still no response from Litchi app or the controller...

Kept calm and though I would shut the drone down by pulling both sticks back and together while the drone was flying over some bushes nearby. The mission was set at 5mph and 150ft height, wanted to try and keep damage minimal...but the drone kept on going FFS!

The mission was on a 225ft radius so I could see the drone 90% of the time, it would go behind roof of building for about 30 seconds, looked like it was going to keep orbiting until the battery died...Remote still bleeping with RTH and now critical battery bleeping!

I was expecting the worst and waited but then I saw the drone stop and start heading back but I still couldn't regain manual control, so grabbed it when it was landing before it went into bushes about 4ft away from take-off point and killed the motors before breathing a big sigh of relief...

All I can think off is that there was a cell tower mast about 200 meters away?

Makes me wary about flying Litchi again in case of a Fly Away or the same happens.

Going to download flight data from drone and upload to see if any experts can see what caused this...

 

[Fly Dawg]

All I can think off is that there was a cell tower mast about 200 meters away?

Cell towers won't interfere with signal. Especially not at 200 meters. Like I mentioned previously, Litchi's flight data leaves a lot to be desired, however in your case, since you have the aircraft, you can retrieve the .dat file from it. Let's see the Litchi data first, then if needed, we can move to the .dat for a much more detailed look.

 

[T Dogg]

Cell towers won't interfere with signal. Especially not at 200 meters. Like I mentioned previously, Litchi's flight data leaves a lot to be desired, however in your case, since you have the aircraft, you can retrieve the .dat file from it. Let's see the Litchi data first, then if needed, we can move to the .dat for a much more detailed look.

Thanks for the quick reply Fly Dawg. In just working out how to get the .dat file and Litchi, will upload when sorted?

 

[Fly Dawg]

In just working out how to get the .dat file

You will need to upload the .dat file to a sharable site such as Dropbox, Google Drive etc...and share a link back here. They are too large to directly upload here. Instructions for the .dat can be found here: Retrieve a V3 Dat