Phantom 4 Pro Flyaway

[fuzzylogic]

It will take time to analyse the data properly.
But the data seems to be telling an interesting story.
While you were using sport mode, you weren't flying towards home.
This used up battery quickly without bringing the Phantom much closer.
I don't think it's correct to say that your Phantom flew away.
It appears that it was under your control and you flew it away.

It looks like there may have been a problem with GPS but this is only for the last 5 seconds of the recorded flight data.
Looking at the way you were having trouble flying towards home, I don't think this would have made much difference to the outcome.

It flew away, and there was problem with GPS. After that problem it start to fly away from me and in a few seconds signal was lost.

 

[sar104]

That's a mystery to me too.
The reason is not clear but by that stage, the damage was done and the Phantom was not being piloted back towards home anyway.

Agreed, but whether it switched back to GPS mode or drifted in ATTI until out of battery after the loss of signal (if that's what happened) would make a big difference to where it ended up.

 

[fuzzylogic]

I'm a video hobbyst, not professional like msinger o meta, but i'm curious hahaha. PhantomLog didn't say "GPS malfunction" or something in the last seconds... only say "satellite positioning off" and in these moment ATTI mode was engaged. Seems like the pilot has activated ATTI mode manually.

Perhaps you miss the switch position and you manually (by mistake) put P4P in ATTI mode. I'm wrong?

It's not correct. I didn't switch it po Atti mode. There was gps error, after that it switched to Atti mode.

 

[fuzzylogic]

Agreed, but whether it switched back to GPS mode or drifted in ATTI until out of battery after the loss of signal (if that's what happened) would make a big difference to where it ended up.

Yes, it will make big difference, beacause I try to figure drone autolanding locations. As I understand, it will start autolanding procedure when battery drop below 10% percent. In this case, it has 11 percent flight time and also 30-40 seconds for autolanding. So I need to know how long it will take to get from 21% to 10%.

 

[sar104]

Yes, it will make big difference, beacause I try to figure drone autolanding locations. As I understand, it will start autolanding procedure when battery drop below 10% percent. In this case, it has 11 percent flight time and also 30-40 seconds for autolanding. So I need to know how long it will take to get from 21% to 10%.

You probably need to bound those possibilities. If it stayed in ATTI then you have a pretty good direction and speed from the last few points that gives you a line to work along, if the terrain is actually traversable. If, at any time, it went back to GPS mode then it will have held position or moved slowly towards the home point. Realistically that just widens the line somewhat, given the relative bearing of the home point to the wind direction and the slow progress it would make into the wind.

Drifiting in ATTI it might have lasted 3 - 4 minutes, while fighting the head wind in GPS it would probably be around half of that.

 

[m0j0]

Sorry about your lost Phantom that is horrible.

This was not a flyaway. This was a giveaway. A sequence of pilot errors that resulted in the loss of your Phantom. I'm sorry about that I hope new pilots learn a few basic principles.

Wind is not your friend.

It's windier the higher you are above the ground - sometimes drastically windier.

If you notice the bird going away from you and you are not making headway when you are trying to bring it back at full throttle... switch to sport mode and descend - especially if your are 600 feet above the ground. At that altitude you are really in danger on windy days.

Watch the map...

Last resort identify an alternate landing spot and put it down. I would rather land it in a safe location than risk losing it.

 

[m0j0]

I need some advice from professionals.

[*]When gps module gets out of order and wind blows away the drone what is the possibility that gps module will start operating properly again and the drone will try to get back to take-off point?

I don't see any indication that GPS was an issue. More
Iikely the wind was too great for the Phantom to maintain its position.

[*]Is it possible to define approximate area of drone fall knowing battery charge left (21%), wind speed and direction?

Estimate... yes. @BudWalker has been pretty accurate in predicting this...

[*]Am I right thinking that drone starts autolanding when battery charge decreases at the level of 10%?

Depends but I'm betting that your Phantom autolanded .

 

[fuzzylogic]

Sorry about your lost Phantom that is horrible.

This was not a flyaway. This was a giveaway. A sequence of pilot errors that resulted in the loss of your Phantom. I'm sorry about that I hope new pilots learn a few basic principles.

Wind is not your friend.

It's windier the higher you are above the ground - sometimes drastically windier.

If you notice the bird going away from you and you are not making headway when you are trying to bring it back at full throttle... switch to sport mode and descend - especially if your are 600 feet above the ground. At that altitude you are really in danger on windy days.

Watch the map...

Last resort identify an alternate landing spot and put it down. I would rather land it in a safe location than risk losing it.

I will try to explain my decision to switch drone to sport mode and change direction. When it started RTH I noticed that it takes too much time to overcome short distance. So I check territory from above and find small glade with not so many trees. I switched to sport mode and start to fly to this glade. Also I started to descend. And it was my main error, because when I took drone to 100-130 meters from the ground - signal became unstable, because trees started to block signal from drone to RC. I should fly to this glade without descending, than check this glade once more and give drone to land on this glade. But there was a gps error and I have no chance to get drone back to me, because height was to small and trees started to block signal.

 

[fuzzylogic]

I don't see any indication that GPS was an issue. More
Iikely the wind was too great for the Phantom to maintain its position.



Estimate... yes. @BudWalker has been pretty accurate in predicting this...



Depends but I'm betting that your Phantom autolanded .

I think this video will explain my problem with gps

 

[BudWalker]

.....

Estimate... yes. @BudWalker has been pretty accurate in predicting this...
...

You must have me confused with @msinger. (That would be an honor for me.) He's the one who knows how to locate lost Phantoms by looking at the .txt. I also note that @Meta4 is very good at this and has already provided some predictions. I'm sure there isn't much I can add here. Good luck

 

[neven]

I would like to know what causes GPS off in redundant system with so many satellites available.

 

[fuzzylogic]

Also, сan I trust information about last drone positions and flyaway direction after gps error? Is it correct position and direction? Also, how can it determine speed of the drone in Atti mode if gps doesn't work?

 

[fuzzylogic]

I would like to know what causes GPS off in redundant system with so many satellites available.

It sometimes happes with P4P.

 

[m0j0]

I see that but it seemed that the GPS problem was at the very end of the flight.

Even if you lose signal by dropping altitude you still have a chance to bring it back. No chance to bring it back at 1000 feet altitude with wind at 17mph on the ground. Wind could be 30+ at that altitude.

 

[fuzzylogic]

If it stayed i atti, it would have drifted downwind until critical low battery level and autolanded then.
If it regained GPS, it would have gone to RTH but made very little headway and also autolanded when critical low battery level was reached.
I wouldn't like to guess where it will have come down and wherever it is, there are a lot of trees for it to be lost in.

Ok. Thanks for information.
I plan to check territory from drones and search in the forest once more.
I understand that it will be guess, but maybe you can ssume an approximate area of search, based on your experience. I will be grateful for your help

 

[neven]

It sometimes happes with P4P.

That is not the answer I want to hear

When doing out of LOS autonomous missions with no connection between AC and RC, you need rock solid GPS. If it glitches it ain't coming back.

*before someone gives me the lecture how those are not alowed let me say that I have all permits for doing them

 

[bkushner]

A few months back myself and others were getting GPS mismatch or something like that and bird was switching to Atti and doing it's own thing. I was closeby when it did it and got home...There was another member in England I believe that had the fight of his life getting bird back....not sure what caused it and haven't had a problem since.

 

[m0j0]

Interesting.. didn't know the P4p was having these problems. Never had this happen with any DJI product.

 

[neven]

A few months back myself and others were getting GPS mismatch or something like that and bird was switching to Atti and doing it's own thing. I was closeby when it did it and got home...There was another member in England I believe that had the fight of his life getting bird back....not sure what caused it and haven't had a problem since.

I remember your post about that. It was in ATTI for just few moments right? I wander would Litchi, GS or Autopilot mission recover from that.

 

[m0j0]

I remember your post about that. It was in ATTI for just few moments right? I wander would Litchi, GS or Autopilot mission recover from that.

Not cool that's for sure