Another Mavic pro has been lost

alex-fe · Nov 24, 2017

Hello, my Mavic pro lost signal and got disconnected tonight.

Could you please look at my log file and comment what went wrong:
DJI Flight Log Viewer - PhantomHelp.com

It has been lost somewhere inside a highly secure lux condo consisting of 3 buildings 30+ floors each.
I guess it's unlikely to find my Mavic in a working condition (I heard a loud boom in the moment of the crush) but maybe you can give me a clue where can I find the remains.

Bunny Too · Nov 24, 2017

alex-fe said:
Hello, my Mavic pro lost signal and got disconnected tonight.

Could you please look at my log file and comment what went wrong:
DJI Flight Log Viewer - PhantomHelp.com

It has been lost somewhere inside a highly secure lux condo consisting of 3 buildings 30+ floors each.
I guess it's unlikely to find my Mavic in a working condition (I heard a loud boom in the moment of the crush) but maybe you can give me a clue where can I find the remains.

Howdy from Wyoming alex-fe, welcome to the community, plenty of fine folk and excellent information here. I am sorry to hear of your loss, I hope someone can help with you log files.

pixl · Nov 24, 2017

My guess is that it's sitting at the base of Victoria Towers, Tower 1.

Launching from your balcony, with strong interference was a bad call, IMO. Next time, maybe try the waterfront? We see a lot of crashes around here related to flying in dense urban areas, especially Hong Kong.

alex-fe · Nov 24, 2017

Thank you, Bunny Too!

pixl said:
My guess is that it's sitting at the base of Victoria Towers, Tower 1.

Launching from your balcony, with strong interference was a bad call, IMO. Next time, maybe try the waterfront?

From the rooftop. Anyway, it's hard to disagree. Surely, my bad.

pixl · Nov 24, 2017

alex-fe said:
Thank you, Bunny Too!

From the rooftop. Anyway, it's hard to disagree. Surely, my bad.

Looks like I had the direction reversed on what your path was -- Google earth threw me off. Apologies. So yeah.. Austin Towers across the street...it was Autolanding for 10 seconds...it's conceivable that it could've found an ok spot to land...worth a look.

dewster · Nov 24, 2017

Tall building obstruct GPS reception. Mountains do the same. There's a lot of metal in balconies which also cause interference with the compasses.

My first drone made a similar noise after crashing. I thought it went through a parked car's window or the window of a house. That thing weighed seven pounds. So imagine the thoughts that went through my head.

sar104 · Nov 24, 2017

It's last recorded position was 22.30384113, 114.16757552, facing east, heading north at 8.5 m/s (due to full left aileron - why were you doing that?) and descending through 60 m at 3 m/s in autolanding mode (why did you trigger that?).

It must have been quite close to that building and obstacle avoidance was disabled on autoland, but it does not appear to have hit it. Where it ended up depends on whether the uplink was maintained and whether you kept providing stick inputs. If it continued north at 8.5 m/s while descending 60 m at 3 m/s then it could have travelled another couple of hundred meters north. If it lost uplink or you centered the sticks it would have gone into a vertical descent. If it received other stick inputs then it could have gone in any direction.

DJIFlightRecord_2017-11-24_[21-23-54].jpg

sar104 · Nov 24, 2017

alex-fe said:
Thank you, Bunny Too!

From the rooftop. Anyway, it's hard to disagree. Surely, my bad.

If you took off from the roof then the recorded absolute elevations were incorrect. It doesn't change the result much, but makes more sense of the flight path - you were over the tall building opposite. I've corrected the flight track based on a takeoff elevation of 55 m. That potentially adds another 15 or 20 seconds to the descent time.

Note that the VPS system did record altitudes briefly towards the end of the record, consistent with the track crossing the edge of the building roof.