Mavic completely lost connection right after warranty, GONE.

[sar104]

In spite of the barrier of the mountain, is it possible the uplink continued well into the approximate 20 second time frame (until impact) of the last trajectory, and simply did not have sufficient time to effect RTH? Time to impact is based on last known speed and distance to the mountain side you cite.

I've actually never seen a documented case of continued uplink after downlink was lost, so I don't know if it ever happens. But even if it does, in this case the sudden loss of downlink implies a pretty solid barrier, and that is supported by the flight track and DEM. Uplink would have gone down very shortly afterwards if not at the same time.

 

[Muz061]

Would obstacle avoidance detect a white-out snow covered mountain? I would have thought it would fit into the same category as drones flying low over water which struggle to detect distance.

 

[Moose1967]

I apologize for my previous post - appears the RTH of 100 meters was plenty - and yes it would climb above the Home Point by 100 meters and then fly home after the disconnect - in a perfect world - so not Pilot Error IMO on the RTH setting - you did mention it was snowing pretty heavy too - how heavy ? Were you recording at the time of disconnect maybe you can upload the video ? Also was collision avoidance turned on ?? How many satellites were you getting and what flight mode were you in (ATI, GPS or Sport Mode). Also what percentage of the battery at time of disconnect ??

 

[AMann]

In my opinion pilot error - RTH wasnt set high enough - did u have collision avoidance turned off - the drone will go up and over the object of it can but maybe you were down too far - at some point it probably forced landed into the mountain - what's odd is another member said you were -312 feet - why didnt the drone fly up to the rth then home - it is possible you backed it in to rhe mountain too.

It's possible that the sensors couldn't detect a featureless white snow covered hillside, especially at the speed the craft may have been going. Had they been sonar type sensors, they may have if the snow didn’t attenuate the signal too much and the drone was flying slower.

 

[AMann]

Would obstacle avoidance detect a white-out snow covered mountain? I would have thought it would fit into the same category as drones flying low over water which struggle to detect distance.

You beat me to the post...

 

[sar104]

It's possible that the sensors couldn't detect a featureless white snow covered hillside, especially at the speed the craft may have been going. Had they been sonar type sensors, they may have if the snow didn’t attenuate the signal too much and the drone was flying slower.

But there is no reason why the sensors would have been required - the RTH height was more than enough to clear the ridgeline.

 

[AMann]

But there is no reason why the sensors would have been required - the RTH height was more than enough to clear the ridgeline.

You are right, I was just commenting about the .sensors

 

[Moose1967]

The other possibility at time of disconnect around the mountain, is he lost satellites and positioning and the craft was in error - maybe altitude and direction was messed up - it was unsure of where to go and in what direction. He did say it was snowing a lot too and I can't see that as a positive either.

 

[sar104]

The other possibility at time of disconnect around the mountain, is he lost satellites and positioning and the craft was in error - maybe altitude and direction was messed up - it was unsure of where to go and in what direction. He did say it was snowing a lot too and I can't see that as a positive either.

Heavy snow could have been an issue, but loss of GPS reception is very unlikely. The aircraft was receiving 19 satellites at the time of the disconnect.

 

[Moose1967]

I agree heavy snow may have been the deciding factor - I don't fly when its snowing - I once got caught in light snow flurries and hurried home with no issues.

 

[Rodkat]

Is it possible it crashed into the terrain while ascending to RTH altitude but before achieving it? I only ask as I was flying my MP in Timor Leste and flew it too far around a headland and lost signal. It was about 25m alt over water at the time and RTH was set at 75m, i regained signal at about 60m alt and cancelled RTH but it had already travelled over 100m in a straight line towards home point and the headland.

 

[Bob4131]

Is it possible it crashed into the terrain while ascending to RTH altitude but before achieving it? I only ask as I was flying my MP in Timor Leste and flew it too far around a headland and lost signal. It was about 25m alt over water at the time and RTH was set at 75m, i regained signal at about 60m alt and cancelled RTH but it had already travelled over 100m in a straight line towards home point and the headland.

I am asking a question that might help...I always thought if the drone lost connection, it would fly straight at the speed it was going for ~ 3 seconds then stop, hover, then go straight up and only then start flying home. But are you saying it starts flying home before it goes up to its rth attitude? This explains a situation I have encountered (without loss of the drone).

 

[Mossiback]

I am asking a question that might help...I always thought if the drone lost connection, it would fly straight at the speed it was going for ~ 3 seconds then stop, hover, then go straight up and only then start flying home. But are you saying it starts flying home before it goes up to its rth attitude? This explains a situation I have encountered (without loss of the drone).

Depends on which Mavic. Given that it is not close to the home point, the MP/MPP will rise up the the set RTH altitude if it is below it or maintain height if above it, and then fly home. The M2 will retrace the last 60 seconds of flight and then raise up or maintain height and fly back.

 

[sar104]

I am asking a question that might help...I always thought if the drone lost connection, it would fly straight at the speed it was going for ~ 3 seconds then stop, hover, then go straight up and only then start flying home. But are you saying it starts flying home before it goes up to its rth attitude? This explains a situation I have encountered (without loss of the drone).

It ascends to RTH height and then returns home - either immediately (MP) or after 60 seconds of being unable to regain the uplink by retracing its flight path (MA and M2).