P4 Lost; Help please.

[atjt7]

Hi All,
I think its just about all my fault but I lost my P4 today.
I was taking some vid and pics of a local mountain rock face when I lost signal and although it tried to return home (I got the message; do you want to return home and clicked ok) but it never came back.
The mountain is about 300m high but I took off from a field below because it was too windy up top and too many trees when I tried after climbing it yesterday.
Anyway my return to home was set at 30m but as the trees closest to the field were around 20m I did reset that after launch to 50m just to be safe.
I am thinking now that as the drone was at around 290m high when it lost signal, that when the return to home activated it went straight down and tried to get to 50m and crashed into the trees or hillside...?
I never even thought about that as usually I just fly at normal ground level not up close to a high rock face. And yes I do feel stupid....
The hillside is a mass of trees, steep gulley's, fallen down trees, long grass, rocks etc etc.
I still had the map on my ipad of where the drome was last at and so I set off to see if I could get near it.
Due to the terrain and the fact that it was going to be dark soon (and the ipad lost battery) I only got to within 300m of where the red arrow said it last was.
I am wondering that when I try looking again tomorrow, will the last location still be on my ipad map if I connect the transmitter?
I am hoping that if it did just go straight down then there is a small chance of finding it if I can get near the arrow...?
I did try when I got back home and recharged the ipad and it seemed to show the red arrow was still there...

I think its a long shot that I will find it anyway in that terrain but I have to try.

Thanks guys in advance.

 

[PaulSouthport]

first thing, take a snap shot (power and home) of the map so you don't lose it.

 

[coco777]

The RTH height is relative to take off point. So that is 50m, you say this mountain is 300m ? Do you do maths at all ?

 

[Donald Christie]

I live in the mountains and face this terrain all the time. The drone should have remained at its current altitude, headed back to the home point, then dropped altitude. The problem lies when you put something between you and the drone higher than your current altitude. Was there anything preventing it from flying at 290m safely back home? The rth height is your minimum height, it should not descend to this height upon rth. Could it have run low on battery?


Sent from my iPad using PhantomPilots

 

[Steve7777]

Hi All,
I think its just about all my fault but I lost my P4 today.
I was taking some vid and pics of a local mountain rock face when I lost signal and although it tried to return home (I got the message; do you want to return home and clicked ok) but it never came back.
The mountain is about 300m high but I took off from a field below because it was too windy up top and too many trees when I tried after climbing it yesterday.
Anyway my return to home was set at 30m but as the trees closest to the field were around 20m I did reset that after launch to 50m just to be safe.
I am thinking now that as the drone was at around 290m high when it lost signal, that when the return to home activated it went straight down and tried to get to 50m and crashed into the trees or hillside...?
I never even thought about that as usually I just fly at normal ground level not up close to a high rock face. And yes I do feel stupid....
The hillside is a mass of trees, steep gulley's, fallen down trees, long grass, rocks etc etc.
I still had the map on my ipad of where the drome was last at and so I set off to see if I could get near it.
Due to the terrain and the fact that it was going to be dark soon (and the ipad lost battery) I only got to within 300m of where the red arrow said it last was.
I am wondering that when I try looking again tomorrow, will the last location still be on my ipad map if I connect the transmitter?
I am hoping that if it did just go straight down then there is a small chance of finding it if I can get near the arrow...?
I did try when I got back home and recharged the ipad and it seemed to show the red arrow was still there...

I think its a long shot that I will find it anyway in that terrain but I have to try.

Thanks guys in advance.

I may be wrong but I thought that if a P4 was above the RTH height, on RTH being activated it would return home at the higher altitude and then go down to home. Of course, 'about 300 m high' for the mountain is above the 290 m you say it was at when it lost signal - but you might have been lucky. But sadly the fact remains that at present it seems to be lost, but hopefully only temporarily. Good luck anyway!

(Later: Aha! Someone (above) agrees...)

 

[atjt7]

It did have enough battery to get home easily as only 700m away when RTH activated and had I think 10 mins left so shouldn't be that.
There still seems to be some confusion regarding whether it drops to set RTH altitude or flies home at current altitude when signal is lost...?
I was flying almost all the time to one side of the mountain face so it should have had a direct path home...

 

[Mark The Droner]

..
There still seems to be some confusion regarding whether it drops to set RTH altitude or flies home at current altitude when signal is lost...?
...

It doesn't drop until it's over the home point.

There was a similar thread a few days ago. If the signal is intermittent, you may think it's connected or disconnected, and your app may tell you it's connected or disconnected when in fact the AC is receiving an intermittent signal even though your app is not. So you push RTH and the AC doesn't get the message because the signal is coming and going. The fool-proof method of getting your AC home in that case is to simply turn your controller off. That way you know for sure it is receiving no signal and it will RTH (if that's how you have it set). So the AC may have hovered, waiting patiently for either your command or a three-second broken signal, got neither, and then auto-landed.

Another possibility is it blew to the other side of the mountain and then RTH'd and hit the mountain. You did mention wind. You could have become disoriented and not realized it.

Sorry for your loss.

 

[msinger]

I am wondering that when I try looking again tomorrow, will the last location still be on my ipad map if I connect the transmitter?

It'll be easier to find the last known location in the TXT flight log that's stored on your mobile device. You can find instructions for retrieving that file here. Once you track it down, please upload the TXT file here if you need help deciphering it.

 

[Donald Christie]

Great point about powering down the remote.


Sent from my iPad using PhantomPilots

 

[alokbhargava]

If your AC was returning back in RTH mode, it will maintain the RTH set height or the actual height whichever is maximum. In such a case chances are there that it hit the mountain rock.


Sent from my iPhone using PhantomPilots

 

[apex1]

The RTH height is relative to take off point. So that is 50m, you say this mountain is 300m ? Do you do maths at all ?

The OP lost his P4 and comes here looking for answers to a question. This is such a helpful response.

 

[Erised]

Send your flight log to msinger, he is THE go to guy to calculate where your bird may be.

 

[TheLightSpeedz]

@msinger has found many of birds! Is THE guy to look at your data!


Sent from my iPhone using PhantomPilots

 

[atjt7]

Went back today for a good search, spent almost 4 hours on very steep bushbashing but no luck.
I took the Tx and the ipad and was still able to see where the last known position was and got right to it after almost 3 hours (not easy with the Tx and ipad in hand on such terrain) but no sign amongst all rocks fallen trees etc.
Still don't know if it tried to descend to 50m or stayed at 290M...?
I will look at retrieving the log data as suggested, thanks guys.

 

[coco777]

Went back today for a good search, spent almost 4 hours on very steep bushbashing but no luck.
I took the Tx and the ipad and was still able to see where the last known position was and got right to it after almost 3 hours (not easy with the Tx and ipad in hand on such terrain) but no sign amongst all rocks fallen trees etc.
Still don't know if it tried to descend to 50m or stayed at 290M...?
I will look at retrieving the log data as suggested, thanks guys.

RTH will return the drone at the set height relevant to take off point.

If you were at the top of a mountain and went down -200m, you would need a RTH height of +20m to come back at a height 20m above take off point.

If you were at the bottom of a mountain and went up +300m, you would need a RTH height of +300m.

 

[Donald Christie]

I had a phantom 3 go down in a neighboring property when the battery unlocked. The last known position was only up to the point the controller still had signal. My aircraft was much farther out than my iPad led me to believe due to forward momentum. Don't take the last known position too literally. Just think about how the aircraft should have behaved in a lost connection or low battery scenario. If it didn't strike the rock face, it could be anywhere along a direct line back to the home point. You are probably already thinking along these lines, but I just wanted to add my thoughts. I lost a p3p in a deep, fast flowing river and I know what the loss feels like. Know anyone who could fly a recon mission?


Sent from my iPad using PhantomPilots

 

[atjt7]

I was able to retrieve the log data and video cache following the link from msinger (big thanks).
Its a bit strange... The last video (it seems I need a "info" file viewer to view the photos) which is just before it lost contact shows the drone virtually level with the top of the mountain.
But the map of the route shows that it then flew straight into the side of the hill about 4 mins after it lost contact but a fair bit lower down...
The more puzzling thing is that the straight line it shows into the hill (around 30 to 60m long by estimate) would have taken it south of the home point if it had continued home. If I draw a line from where it lost contact and started to fly into the hill I estimate it would have ended up several hundred meters south of the home point if it had continued...? The map of the route shows that it should have missed the rock and been able to fly home if it had maintained the same altitude.
I climbed the Mountain again today by the tourist route when I saw the video (because I thought it must be very near the top) but that was before I had seen that it flew into the hill lower down. It rained at the top and I had to abandon the search again for safety.
Now it seems it is right on the border of a steep rock face and the steep slope with all the vegetation and dead trees, fallen rocks etc...

Its raining again now so will have to wait for a day or so to dry the rock out so it is safer to search.
I am not sure how to get a photo or log record on here or it would explain better.

Its very frustrating, I think I know where it should be but the terrain is very difficult and potentially dangerous, snake season too.

 

[kingkong90210]

U need soneone with another drone to do a search, it would be way faster thab on foot

 

[atjt7]

Update.
Sorry for the long time getting back on, but I have not got the P4 back and have been arguing with Dji...

I spent over 12 hours on the side of the mountain over several days including some time on my abseil rope for the more dangerous bits. No sign at all...

Dji have said 'cause unknown" after I uploaded the flight log to their tech team.
They offered me 30% off a new P4 only which I said was crap so after some more to and fro they say the very best they can do is 50% off the drone only.

Its really bad of them I think as they quote a price of $1800AUD for drone only when I can now buy the complete P4 kit in Aus for under $1500.
So basically they want me to pay another $900AUD for the P4 only when obviously its not costing them that so they are really making profit from me twice...

It makes me really annoyed that they would do this.

They have said I can take the 50% off a Mavic instead (I asked) but they cannot guarantee when it would be but would definitely be several months as stock is so tight.

I really wish I could take legal action but simply cannot afford it. A class action would be nice...

 

[msinger]

atjt7, if you'd like us to comment on your flight log, please upload it here and post a link back here.