P3S makes unplanned descent during mission - now lost

[UnluckyInFlight]

While running a set of waypoints that I've used several times (four stops, all above 150'), my drone decided to descend from just under 400 feet while at stop 1. The last thing I saw through the camera was a tree at about 68 feet altitude. I tried adding thrust, but it seemed to not respond, then signal lost (as well as drone).

I looked at the flight data, and it showed just that. There was one additional data point about 3 seconds later and 100 yards away at a height of 65 ft in the direction of way point 2. Then nothing.

Can anyone explain this behavior? Anyone have any ideas? There are 100 ft trees between stop 1 and stop 2, so as of now I am guessing it;s in that mess. But then why would it be headed to stop 2 at 65 feet? Why on earth would it descend during a set of way points? Frustrated.

Any input is greatly appreciated.

 

[Pharm]

What was the set altitude of the second waypoint? What app were you using (Litchi, Autopilot, DJI Go)?

 

[Fly Dawg]

From what you said, I assume that you mean that you have executed this same mission profile several times. If that is correct, off the top of my head I can't think of any reason for this, except an app update or a device system update prior to this flight. It is possible that upon that update, some of the mission data could have been corrupted during that process. I'm just taking a WAG at it without more info. Pharm had a good question as well. The second waypoint. altitude. And I am also assuming you were using Litchi with a P3S for what that's worth.

 

[UnluckyInFlight]

What was the set altitude of the second waypoint? What app were you using (Litchi, Autopilot, DJI Go)?

All of the wayoints were 150 ft. I was using DJI Go on an iPad.

 

[Fly Dawg]

If all of your waypoints were 150 ft, is there any special reason you were at 400 ft, prior to the first waypoint?

 

[Fly Dawg]

Also, between waypoint 1and waypoint 2, what was the set airspeed and distance between the two? Just trying to narrow this down a bit without seeing the flight data.

 

[UnluckyInFlight]

Also, between waypoint 1and waypoint 2, what was the set airspeed and distance between the two? Just trying to narrow this down a bit without seeing the flight data.

Airspeed was set to (around) 20 MPH. Distance between P1 and P2 is about 800 ft

 

[UnluckyInFlight]

Airspeed was set to (around) 20 MPH. Distance between P1 and P2 is about 800 ft

Also, in looking more closely at the data, I hit the throttle (100%) at 88 ft., but the thing continued to descend.

 

[Fly Dawg]

That could have been at a very iffy point in the flight. Take a real close look at the timeline. It could have descended behind the trees and given you intermittent signal and the bird never saw the stick commands. May want to go ahead an upload that flight data for a better look.

 

[Fly Dawg]

That could have been at a very iffy point in the flight. Take a real close look at the timeline. It could have descended behind the trees and given you intermittent signal and the bird never saw the stick commands. May want to go ahead an upload that flight data for a better look.

Or, it lost signal and went in to auto land.

 

[Fly Dawg]

Shouldn't do that with a loaded mission however.

 

[UnluckyInFlight]

Shouldn't do that with a loaded mission however.

Happy to upload the data - not sure how. I'll need to look that up.

And I had a clean signal (and video) from 88 ft where I hit the throttle, down to 68 where it went off-line. This all took place about 725 ft. from the controller.

 

[UnluckyInFlight]

Happy to upload the data - not sure how. I'll need to look that up.

And I had a clean signal (and video) from 88 ft where I hit the throttle, down to 68 where it went off-line. This all took place about 725 ft. from the controller.

If all of your waypoints were 150 ft, is there any special reason you were at 400 ft, prior to the first waypoint?

No particular reason. I had been manually flying around and had it at 400 just to get some range.

 

[Fly Dawg]

Upload it here: https://www.phantomhelp.com/LogViewer/Upload/

 

[UnluckyInFlight]

Upload it here: https://www.phantomhelp.com/LogViewer/Upload/

ok - it's uploaded (DJIFlightRecord_2017-06-11_[15-11-15].txt)

 

[UnluckyInFlight]

ok - it's uploaded (DJIFlightRecord_2017-06-11_[15-11-15].txt)

The waypoint session started around 3:30

 

[UnluckyInFlight]

The waypoint session started around 3:30

DJI Phantom & Mavic Flight Log Viewer - PhantomHelp.com

 

[Fly Dawg]

After a quick look at your data, First you had numerous errors reported early on before the waypoints started.
Also to note, your max speed was 27mph. It appears from what I am looking at that if you indeed had Waypoint 1 set to 150 ft, it did not go there. You started at 398ft at 3:34, reaching waypoint 1 at 4:08.8. And still at 384 ft.
If I get time I will look at the CSV data and see if I can tell anything else from that. But I would say that it indeed started descending at waypoint 1, it never accelerated forward to waypoint 2. It just started slowly descending. Something that within VLOS should have been easily manually corrected by canceling the mission. None the less I will look more and possibly forward this to another.

 

[UnluckyInFlight]

After a quick look at your data, First you had numerous errors reported early on before the waypoints started.
Also to note, your max speed was 27mph. It appears from what I am looking at that if you indeed had Waypoint 1 set to 150 ft, it did not go there. You started at 398ft at 3:34, reaching waypoint 1 at 4:08.8. And still at 384 ft.
If I get time I will look at the CSV data and see if I can tell anything else from that. But I would say that it indeed started descending at waypoint 1, it never accelerated forward to waypoint 2. It just started slowly descending. Something that within VLOS should have been easily manually corrected by canceling the mission. None the less I will look more and possibly forward this to another.

BTW - I really appreciate you looking at this!

My immediate conclusion was 'pilot error', but I can't find anything I did wrong. Perhaps my biggest fault was not reacting fast enough when I saw something was going wrong. When I saw it start to descend from 400, I just thought it was going to stop around 150, and proceed to P2. When I saw it go below that I guess I panicked a bit, and acted too late. Good thing there were no passengers on my aircraft!

I think my end goal for right now is to determine the best place to search. I've already spoken to a number of neighbors, and looked in and on (as best I could) the patch of trees in the flight line to P2.

Do you know if there are any avenues for restitution with DJI in the event this is some sort of malfunction?

Also, is there way to review the pre-programmed waypoints it was flying on?

 

[UnluckyInFlight]

After a quick look at your data, First you had numerous errors reported early on before the waypoints started.
Also to note, your max speed was 27mph. It appears from what I am looking at that if you indeed had Waypoint 1 set to 150 ft, it did not go there. You started at 398ft at 3:34, reaching waypoint 1 at 4:08.8. And still at 384 ft.
If I get time I will look at the CSV data and see if I can tell anything else from that. But I would say that it indeed started descending at waypoint 1, it never accelerated forward to waypoint 2. It just started slowly descending. Something that within VLOS should have been easily manually corrected by canceling the mission. None the less I will look more and possibly forward this to another.

Also, re: the error messages: I was getting those messages no matter where or when I flew. I went to the rec fields about a mile from my house with no one, and nothing around. Still got them.