Hi there. Borrowed a Phantom 3 from a friend on Friday to do some aerail shots of a mountain cabin. Aprox altitude 1700 m ASL. Once I got it up in the air I noticed some movement from the wind but nothing very serious untill it started flying away from me despite me trying to bring it back. Fearing a crash I kept it up in the air and tried to use RTH when I could not see it clearly anymore. The drone kept going away and I lost it in the woods. I attach the final two logs and I would appreciate an analysis of the data to help me avoid the same mistake in the future.

http://www.phantomhelp.com/LogViewer/L5N5IZVRHHHVHOFI2E49/#
http://www.phantomhelp.com/LogViewer/9AY7636S4LSW5SRJQIFB/

Thank you

Cristian

I'm no expert on reading the logs, but it looks like RTH was active, but the wind was too strong and it was continuing to move away.

I'll put in my two cents and I'm sure others will too...

Sorry but it looks to me like you made quite a few rookie mistakes on this flight.

1)  You should always launch with a fully charged battery.   81% isn't good enough.  If you choose to launch with 81%, you accept the risk of a battery malfunction.

2)  You initially flew below the tree line out of line of sight of your controller which caused the first loss of signal and the first RTH.  

3)  You should have released the sticks when you lost the connection, but apparently didn't.  The AC appears to have regained the signal for enough time to sense stick movement and therefore cancelled the RTH ascent and began flying straight home at negative altitude, which is extremely dangerous.  

4)  You should have checked a wind app before your flight.  It appears you had a hill or mountain behind you, which is to say to the east of you.  Apparently the wind was extremely strong and coming from the east which explains the movement away from the home point when it should have been moving towards the home point.  So the AC was likely flying backwards.  This RTH scenario of flying away from homepoint at a very slow speed is repeated over and over in both logs.  If you had checked a wind app before your flight, you'd have realized it was too windy to fly.

www.windy.com

https://phantompilots.com/threads/high-wind-warning-in-very-little-wind.104160/#post-1073005

5)  You should not fly downwind when it's windy.  If you choose to fly, you must fly upwind.  

Sorry for your loss.

Forget using wind apps (they're not to be relied on anyway).
You should have felt the wind on your face and felt the speed and direction of the wind and seen its effect on the trees.
You flew away in the direction of the wind which meant the Phantom wpuld have to fight a headwind to return.
Look at the log from 4:01.3 - 4:57.3 where the Phantom was ascending to RTH for the last time.
With no joystick input the Phantom lost 256 metres in 56 seconds while ascending 34 metres.
It was unable to maintain horizontal position because the wind was too strong and blowing it further away.
The second flight log shows the Phantom in RTH losing more distance as it tries to fly against the headwind but going backwards at 2.5-4 metres/second.
That suggests a wind strength of about 12-15 m/sec
The Phantom can fly at 15 m/sec when you control it but RTH is slower at 10 m/sec.
Flying off to the west was a mistake.
Leaving the Phantom going backwards in RTH and not taking control was another mistake.
These mistakes are why the Phantom was lost.

Hi Mark and Mark. Thanks for your comments. There are definetly some lessons to be learned here. The position I started from was the highest point in the area so I had a good line to the drone all the time. When I saw the aircraft was not returning I might have panicked and tried to manually bring it back if it also shows up in the log. The UAV forecast app was showing all green except some cloud cover and the wind on the take off ground was very light but perhaps a few hundred feet up things were completly different. The one most important thing I did not do was to lower the god damn thing but I really panicked...

Labroides Posted at 2018-6-3 13:48
Forget using wind apps (they're not to be relied on anyway).
You should have felt the wind on your face and felt the speed and direction of the wind and seen its effect on the trees.
You flew away in the direction of the wind which meant the Phantom wpuld have to fight a headwind to return.

yup...I guess I started my flying "career" in very bad conditions. I took too much confidence in technology without having proper flight training and it proved very costly. Thanks for the info

Hi Cristian, we're so sorry to read the incident. If the drone is still under warranty period, please kindly contact our support and start a case: https://www.dji.com/support Data analysis is suggested to check the exact status.

It kinda looks like the wind was the main factor here.  The RTH altitude was set pretty high, so when it accended to that altitude it made matters worse.  It does appear that you were working hard to bring it back. When I was starting out with my first P3S in 2016,  I did almost the same thing.  I nearly lost it due to the wind, and not knowing which way the drone was facing.  At that point in my drone flying career, I did not know how to rely on my Go Ap instruments to determine which way it was facing.  It never occurred to me to look at that little blue triangle on the radar screen.  I panicked and started running downwind after the damn thing.  By the time I finally had enough sense to hit the RTH button I was two hundred yards from my Home position.  The  Standard was able to overcome the wind speed and flew directly over my head on its way back to the Home Point.  When I got back to my truck, the damn thing was sitting on the ground waiting for me to RTH.  I think that was only my second distance flight, and I learned a valuable lesson.

Not knowing your exact situation, I think what I would have done in your case, would have been to get the drone to a lower altitude, point the triangle back toward me and jammed the throttle forward.  I would have really been on those instruments to see if the distance was decreasing.  If all else failed, I think I would have hit Auto-land and let it come down where ever it was at that point.  Better to have a broken drone from a bad landing, than no drone at all to repair.  You could point the camera down and try to maneuver to a safe landing.

Of course, I wasn't there.  I know you did the best you could at the time.

DJI Susan Posted at 2018-6-4 02:52
Hi Cristian, we're so sorry to read the incident. If the drone is still under warranty period, please kindly contact our support and start a case: https://www.dji.com/support Data analysis is suggested to check the exact status.

Thanks, I will do that

Mark The Droner Posted at 2018-6-3 13:20
I'll put in my two cents and I'm sure others will too...

Sorry but it looks to me like you made quite a few rookie mistakes on this flight.

Just one question..why there was no wind warning in the app ? Is this warning available only in some models ?

I think I found a clue to my mishap. While watching the replay on my tablet I see a warning saying attitude mode on. There is a switch on the remote that toggles that, right? I must have flipped it my mistake befor taking off...

ATTI mode, if you were in it, would not disable RTH.  OTOH, if you had lost satellites somehow and had no GPS, then of course RTH would not work.  But your logs didn't show anything like that.  

I think only the P4s have the wind warning.  

The part I don't quite understand is how you described in post #5 that you were at the highest point in the area and yet you say the wind was very light.  

cristiopr3a Posted at 2018-6-4 14:04
I think I found a clue to my mishap. While watching the replay on my tablet I see a warning saying attitude mode on. There is a switch on the remote that toggles that, right? I must have flipped it my mistake befor taking off...

I think I found a clue to my mishap. While watching the replay on my tablet I see a warning saying attitude mode on.
Not on this flight.
The recorded flight data shows you were in P-GPS the whole time and never went into Atti mode.

Regarding the UAV forecast app. In the settings, you can set the altitude for the wind speed at that height. I set my altitude for my RTH Height. The main screen then will show the speed for that heigth. Took me a while to find that.  i.e., you can set the threshold for all the setting on the main screen.

I would still use weather apps, if only to get a rough idea as to the wind speed, after all, they are mostly taken from the GFS forecast or the ECMWF forecast, they are quite accurate for 10m wind speeds, UAV uses Dark Sky forecasts and Dark Sky are fairly good, not sure what they are basing their wind height on though, its possible its based on an estimate from the 10m and 100m heights, therefore this will be adequate for a go or no go for flight. As for Windy, these too are extremely good but the only do surface (10m) then the next jump is to 100m and so on, again, a very good service if only to gain an idea as to the speeds. If its windy in your face then its going to be worse higher up, reason being is because there is no objects to slow it down, standing in your back garden compared to the middle of a field are totally different, what can seem a calm day in the suburbs could be in fact 8mph out in the fields and a forecast app such as dark sky, UAV Forecast, Windy, WeatherPro and many more and very much a worthy tool to use, as long as you bear in mind it is just a forecast, it could be higher or lower or spot on, but we are not talking 10mph out prob around  1 to 8mph if that much, but the odd gust could reach a little more but again, unlikely.

If you want to get a good idea as to where you at the time is to use an app like Weather Underground, they have many private weather stations and many METARs (airports etc) so you can get a live reading there and then from your nearest station, bear in mind many METARs update hourly and normally around 50 - 00 so best to view METARs after 05, bear in mind these only give you 10m heights at best, but if its 30mph gusts then you know ya dicing with a dear loss lol

Hi Laborides. Please see attached screenshot from the flight.

And here it is , same message from the previous flight, same day

cristiopr3a Posted at 2018-6-4 20:51
Hi Laborides. Please see attached screenshot from the flight.

The recorded flight data for that time of the flight shows P-GPS for every 1/10th of a second and no Atti mode appears anywhere in the data.
You'll note that the top of the screen in your screenshots also indicates the Phantom was in P-GPS mode.
The atti message must have been a temporary false alarm.

Mark The Droner Posted at 2018-6-4 14:44
ATTI mode, if you were in it, would not disable RTH.  OTOH, if you had lost satellites somehow and had no GPS, then of course RTH would not work.  But your logs didn't show anything like that.  

I think only the P4s have the wind warning.  

Hi there. What I meant by highest point was in respect to the area where I was flying. Around the mountain cabin the terrain slopes downward. There is higher gound to the right of the cabin but I was not flying there

cristiopr3a Posted at 2018-6-5 00:55
Hi there. What I meant by highest point was in respect to the area where I was flying. Around the mountain cabin the terrain slopes downward. There is higher gound to the right of the cabin but I was not flying there

In other words, there was higher elevation in the opposite direction... to the east... ?

Mark The Droner Posted at 2018-6-5 02:36
In other words, there was higher elevation in the opposite direction... to the east... ?

Aprox terrain configuration

That looks like a mountain or at least a large hill behind you.  So that would explain why you felt the wind was "very light" at the launch point - and yet your aircraft seemed to be caught in very strong winds coming from the east and apparently sailing over your head.

I suggest that next time you check www.windy.com before you launch - especially if you are launching in hilly or mountainous terrain.   It gives both wind speed and wind direction estimates at 100 meters AGL from three different sources, and these are based on actual wind measurements from places around you.  

Sorry again for your loss and good luck moving forward.

Hey guys. All of a sudden I have received extraordinary news. Somebody that was running in the area training for mountain marathons found the bird ! Out of pure luck the SD card in the drone still had some pictures from my DSLR and this runner recognized a  friend. When I got the call I could not believe my luck !

  Congratulations!!!   

That's amazing!

Mark The Droner Posted at 2018-6-5 09:38
Congratulations!!!

thanks ! feels like x-mas time )

Probably better than that!  You don't have a video do you?  

Mark The Droner Posted at 2018-6-5 09:40
Probably better than that!  You don't have a video do you?

from the on-board camera ? it was not set to record as I was just getting used to the flight controls. Does the drone have an on-board memory that can be downloaded/analyzed ?

Yes, there is a more complete log within the AC that you can get by plugging AC into your desktop with a usb cable.  I don't have a P3S, but I think that's correct...

Congratulations with the reunion, that was a nice read.

Sorry for being curious but i have seen those before and wondered, why does the prop guards have those strings?
Prop guards itself add to the risk it would be hanging high on a branch, should it meet a tree but i think those strings would make sure it got stuck somewhere impossible to reach in case of an accident, that is why i wonder what use they have.

btw. i think that those guards has made it even more difficult for the Phantom to fight the wind in this case.

Labroides Posted at 2018-6-4 15:56
I think I found a clue to my mishap. While watching the replay on my tablet I see a warning saying attitude mode on.
Not on this flight.
The recorded flight data shows you were in P-GPS the whole time and never went into Atti mode.

I must agree

KedDK Posted at 2018-6-5 10:16
Congratulations with the reunion, that was a nice read.

Sorry for being curious but i have seen those before and wondered, why does the prop guards have those strings?

The strings keep it from moving into an obstruction in between the guards. It is a nylon string that comes with the guards. You are right. When it comes limb time the guards and string make a nice coat hangar.

In regards to all of these wind apps, I found the best way to test the wind conditions is by doing it right on the spot where you are flying.  What I do is to take off and then hover at about 50 feet or so.  Not too high!  Generally, the higher you go, the stronger the wind.  Then I turn off the GPS.  By watching how fast and in what direction the drone is moving will tell me if it is safe to fly up that high. If it moves downwind pretty fast, I will give it full throttle and try to move upwind.  You can read the wind speed at that altitude by looking at the VS speed setting on your display as it moves downwind.  This way it is real-time accuracy on the spot.

Rodger8 Posted at 2018-6-5 13:12
The strings keep it from moving into an obstruction in between the guards. It is a nylon string that comes with the guards. You are right. When it comes limb time the guards and string make a nice coat hangar.

Thank you that make some kind of sense even i would not feel safe having those strings there. Looking on the pic above it look like they could break and i can imagine the result if they get caught by a prop ...
I found the other place i noticed those, here, don't look safe either i think, never got a reply when i asked below.

KedDK Posted at 2018-6-5 16:15
Thank you that make some kind of sense even i would not feel safe having those strings there. Looking on the pic above it look like they could break and i can imagine the result if they get caught by a prop ...
I found the other place i noticed those, here, don't look safe either i think, never got a reply when i asked below.

Not a problem. It is a nylon piece that is supplied with the guards, most likely stronger than the guards. Very effective and a pain in the butt to install. Plenty to spare, maybe do a little fishing with the leftover.