Lost Mavic pro

LuVi · Jan 3, 2019

Hi all, they send me from FB and they told me to ask for a user called @sar104 that could help me narrow my search.
Hi all, lost my drone (DJI Mavic Pro) in a fly-away under strong (30 m/s) winds in high mountain (2500 m, -12 °C). Eventually in the next days will be fully covered by snow.

Disconnected at 42%, while "performing" an RTH, but going away under the wind, and suddenly disconnected. I was North, at 1 Km, and the wind was from E to W, at 30m/s the log showed me the last available position, and I reached in about two hours, with crampons, but without an axle could not go on with the search

and the temperature was lowering very quickly.

I have logs until disconnection

Thanks

LuVi · Jan 3, 2019

Here is the log

LuVi · Jan 3, 2019

Last cached video, already in RTH. I was in the center of the scene, you can see the cabin, while the drone was drifting away while under RTH. As the mountain (lower than the drone, 2270 m VS 2490 m) covers the line of sight the drone disconnected. Was moving W at 20 kmh, but still some vector to North, toward my position.

2019_01_01_08_28_53.mp4

Meta4 · Jan 3, 2019

LuVi said:
Hi all, they send me from FB and they told me to ask for a user called @sar104 that could help me narrow my search.
Hi all, lost my drone (DJI Mavic Pro) in a fly-away under strong (30 m/s) winds in high mountain (2500 m, -12 °C). Eventually in the next days will be fully covered by snow.

Disconnected at 42%, while "performing" an RTH, but going away under the wind, and suddenly disconnected. I was North, at 1 Km, and the wind was from E to W, at 30m/s the log showed me the last available position, and I reached in about two hours, with crampons, but without an axle could not go on with the search and the temperature was lowering very quickly.

Here's what your flight data looks like: DJI Flight Log Viewer - PhantomHelp.com

It looks like you didn't want that Mavic to come back.
You just threw it away and did nothing to save it.
You started in an extreme environment with a battery at only 68%.
The winds appear to have been much less than 30 m/s (which would have blown you off the mountain) but still too strong for RTH to fight against and too strong to be flying in.
If the wind had really been blowing at 30 m/s, the flight track would have been a straight line to the west.
From the top of a high mountain, you sent the poor drone up 400 metres where the wind was even stronger.

From 2:26.8 you left the drone hovering and it was unable to hold position, being blown away at 7 m/s
You left the joysticks alone for two minutes and RTH was initiated after two minutes.
You still left the drone 400 metres up and didn't touch the joysticks.

It looks to me like you didn't want the drone.
You launched it into conditions that were unsuitable and made no effort to bring it back.
I see the results of a lot of bad decisions in drone flying but I think yours is the worst.

Going to the point where it was last recorded was a pointless exercise since when last recorded, the drone was 650 metres above the ground and being blown west at 5-5.5 m/s.
It's going to be somewhere much further to the west.
Perhaps Sar104 might be able to give an estimate but there are too many variables and unknowns to be very precise.
I think you should just forget the drone.
The time to make an effort was when you had it in the air - or even before launching.

LuVi · Jan 3, 2019

Thanks @Meta4 I know I made errors, but I was confident that even in this situation I could be able to have an RTH as many times I had in the same conditions. I know I'd rather switch to sport mode and try to contrast wind or, at least, pull up and try to stay in line of sight to avoid disconnection, but I didn't noticed both the alert and the movement until it was too late, while i was doing a pano, so I was distracted by the photographic action on the screen.
30 m/s wind was the value I found in airdata UAV, and being in the area where the drone flow, just one hour later I think it's a good estimate.
As the RC got disconnected I tried to climb up the mountain that, i thought, blocked the signal as fast as i could, but even wearing crampons, I was not able to get to the top in less than 1 hr, so the battery at that point was a frozen plastic block.
Please, note that before the last flight I made another one, shorter, at a lower height, with the same wind reported, and had no issues in coming back home, that's why the battery was at 68%. I had another full charged battery with me. The worst thing was I lost connection before I was able to recognize what was happening.

Anyway I'm trying to plan a SAR mission in the area, before the snow will cover up everything or in spring, so any constructive help to narrow down the search area will be appreciated.

sar104 · Jan 3, 2019

That's a tough one, because of the terrain and wind variability. Here's a best estimate based on the usual extrapolation:

The aircraft was drifting at 5 m/s on a heading of 246° at the end of the log in an 80 km/hr wind. With constant wind speed and direction (probably okay at that altitude) it will have continued for another 230 seconds or so before the battery hit the autoland level of 21%. Then it will have started a 3 m/s descent. Setting the wind as constant through the descent and plotting the resulting flight path against the DEM shows where it would have intersected the ground (see below).

The wind over that last ridge is very hard to predict, and there will have been upslope winds approaching it, but that is probably a reasonable estimate for the maximum travel. If the wind reduced speed as the aircraft descended then it will have slowed its drift and tracked around towards the homeport. Now it gets marginal, because the valley floor is around 1700 m MSL, which would put it around 0% battery if it made it down. That consideration aside, the resulting possible landing area is then defined by the shaded green area below.

LuVi · Jan 3, 2019

@sar104 thanks. This is something really useful. I can plan a SAR mission with more chance of success now or, at least, climb in winter conditions a peak I never climbed before. Really thank you for your detailed analysis. Have a nice day.

sar104 · Jan 3, 2019

LuVi said:
@sar104 thanks. This is something really useful. I can plan a SAR mission with more chance of success now or, at least, climb in winter conditions a peak I never climbed before. Really thank you for your detailed analysis. Have a nice day.

No problem. It's just unfortunate that I couldn't narrow it down to less than 150,000 m². And if the wind speed changed significantly at 2500 m then it could be anywhere on the valley floor between the area I outlined and the direction of the home point.

LuVi · Jan 3, 2019

It's not the wide area, the problem, but there is a large rock wall inside the area, and I cannot climb every part of it in search of my Mavic. Look, this is the way the area was two days ago, and now the things are getting worst (the area is on the right)

Anyway, thank again for the detailed analysis, I will be back in spring

Have a nice day!

Canuk · Jan 3, 2019

Take pictures of your hunt . We all like pictures

sar104 · Jan 3, 2019

LuVi said:
It's not the wide area, the problem, but there is a large rock wall inside the area, and I cannot climb every part of it in search of my Mavic. Look, this is the way the area was two days ago, and now the things are getting worst (the area is on the right)
View attachment 57655

Anyway, thank again for the detailed analysis, I will be back in spring
Have a nice day!

Spectacular scenery. I'd start at the lower end.

LuVi · Jan 4, 2019

sar104 said:
Spectacular scenery. I'd start at the lower end.

I will, but actually the snowstorm is really hard, so I will have to wait spring

Thanks @Canuk I will share pics of the hunt

Babar13 · Jan 4, 2019

LuVi said:
It's not the wide area, the problem, but there is a large rock wall inside the area, and I cannot climb every part of it in search of my Mavic. Look, this is the way the area was two days ago, and now the things are getting worst (the area is on the right)
Anyway, thank again for the detailed analysis, I will be back in spring
Have a nice day!

For me the area IS a problem. 150000 m2 is way too much to let you one single chance to find it. The snow added; just forget it ! Any case your drone will be definitely damaged by humidity pretty soon... Man, that's "dead".

LuVi · Jan 5, 2019

Yes, I know @Babar13 , but I'd like to recover the microSD at least. Anyway, I'm an hiker and a climber, so would be nice for me to visit that area, that I don't know so much.
This morning, from my bedroom window, I can see the landing/crash area...

BD0G · Jan 8, 2019

Snow covering the downed Mavic makes this such a tough recovery. You cannot use another Mavic to fly over with the camera pointed down to see if you can find it as the snow drifts will have covered it by now.

Super tough recovery. Stay with it and as there is a thaw it may reappear.

Oh and ****! SAR104 is now internet and Facebook famous!

DanMan32 · Jan 8, 2019

I have heard of someone recovering his Phantom after being at the bottom of a lake for something like 6 months. It took some work to clean up the mud and dry it out but it flew. Can't remember if the gimbal/camera worked.

So, there's a chance this one will be salvageable once recovered.