Mavic Pro gone...need feedback

[sar104]

I guess I was relying more on the KML files as far as what distance was doing than on the txt. Probably not a good thing. On the KML of log 2, it follows the same route as log 1 then turned at the end with RTH but doesn't seem to come back much if at all. Should have looked more closely at the txt of log 2...

The change in drift rate was due to engaging RTH, which then resulted in a more concerted effort to return.

 

[c.walms]

That's what you get for going up to altitudes that you shouldn't have been at. I have no remorse for people that suffer the consequences of very stupid actions.

Comments like this one just prove there are jerks everywhere.

 

[RayOZ]

Comments like this one just prove there are jerks everywhere.

Works both ways. There are those who are newbie, careless and lost their drones, and there are those that are selfishly irresponsible and lost their drones. We seem to get that a lot these days. So far, only lost drones and no other damage or injury. sar104 has been really nice about it, ignoring how pilots has lost their drone, and just helping to locate it.
As for this said drone, if the last state of RTH is basically not making any headway back, it probably landed around that last spot where it'll start to descend at 10% batt, in the water. Not sure if AC still try to maintain position an auto-land, or it will only descend, and wind can push it back further.

 

[MavicCF]

The change in drift rate was due to engaging RTH, which then resulted in a more concerted effort to return.

View attachment 35299

I admit defeat, why do you think RTH in the first log didn't change anything as compared to when it was initiated in the second? It doesn't even seem like it adjusted its heading in response to the first RTH command.

 

[sar104]

I admit defeat, why do you think RTH in the first log didn't change anything as compared to when it was initiated in the second? It doesn't even seem like it adjusted its heading in response to the first RTH command.

During the first RTH it was already at maximum pitch + roll, and still being blown north. It looks like the wind had dropped a little during final RTH in the second log, allowing it to slow its drift and actually reverse direction, albeit really slowly.

 

[Arnold]

Thank you all, especially @MavicCF, for all your efforts. MavicCF, I feel that the calculations may be off somehwat. If my homepoint is southwest (pear tree point beach) and my last known location is scott's cove. It looked like it was making it's way back at 2 mph in a the direction of the home point. If I cancelled return to home due to low battery (by accident because I was just freaking out) the mavic would have held its position until forced landing. But according to to last data in log 2 before cutting out, it seemed to be heading back really slowly. so I figured that it must be somewhere along the red line (see picture below) or around it's last know location. Of course there's some guessing involved. I did bring the bird down to 600ft which significantly slowed drift, but wind could have picked up or slowed down or even changed direction. If you believe otherwise I'd like to know your thoughts. Thanks again.

 

[ac0j]

Is this picture what the video looks like from 1600'?
If you have any video or pictures from this doomed flight, or any other from 1600' plus. I would love to see what they look like. Maybe it would help me understand the desire to go so high.

 

[Arnold]

I don't consider myself a reckless pilot. I follow the rules because I know what can happen if you don't, and I'm not talking about just losing the drone. It's like driving your car. Sometimes you feel like putting your foot on the gas pedal and going a bit faster than 55 miles per hour. I've never experienced wind like this before, especially since it was absolutely windstill on the ground. An the drone has always held it's position in very strong winds quite well. So I was caught off guard. After a year I just had too much confidence in my drone. There are some who are REALLY reckless and some who just make honest mistakes. ac0j, this is not necessarily directed towards you. but there are some other people who like to judge people they don't even know. It's easy to beat a man when he's down. I took a calculated risk and lost my drone. That's punishment enough and make me a better pilot the next time around. Below is one of the last pics I took pointing west overlooking "holly pond and the long island sound in Darien CT.

 

[joejaxvic123]

Nice pic. About 400' agl?

 

[Arnold]

Is this picture what the video looks like from 1600'?
If you have any video or pictures from this doomed flight, or any other from 1600' plus. I would love to see what they look like. Maybe it would help me understand the desire to go so high.

This one is from Sugarbush Ski Resort in Vermont.

 

[Arnold]

Nice pic. About 400' agl?

1600 AGL, at least that's what the flight log says

 

[ac0j]

This one is from Sugarbush Ski Resort in Vermont.

ok, I get it.... pretty cool!

 

[MavicCF]

Thank you all, especially @MavicCF, for all your efforts. MavicCF, I feel that the calculations may be off somehwat. If my homepoint is southwest (pear tree point beach) and my last known location is scott's cove. It looked like it was making it's way back at 2 mph in a the direction of the home point. If I cancelled return to home due to low battery (by accident because I was just freaking out) the mavic would have held its position until forced landing. But according to to last data in log 2 before cutting out, it seemed to be heading back really slowly. so I figured that it must be somewhere along the red line (see picture below) or around it's last know location. Of course there's some guessing involved. I did bring the bird down to 600ft which significantly slowed drift, but wind could have picked up or slowed down or even changed direction. If you believe otherwise I'd like to know your thoughts. Thanks again.View attachment 35323

My calculations were based mostly on conditions in your second log being the same or similar as in the first log. As Sar104 has pointed out, the difference between the two logs is substantial enough to make my estimate impractical.
Just to add my opinion though, at the end of the second log, the wind was coming from the SW blowing towards the NE. The AC was drifting NE with the wind and entered RTH mode. At that point it started to adjust its course to head home, in so doing, it was flying roughly parallel the wind instead of fighting almost directly against it.That is one reason I believe it was able to gain some distance at the end of the second log. If the log had shown the last 25 degrees of rotation onto the RTH path, it would have been going nearly dead into the wind which I believe would have continued to blow it along my predicted line. I don't know, in RTH mode can the AC pitch farther than it was when it was just trying to position hold? You also dropped in altitude which could totally kill my theory...

Anyway, this image shows the last few seconds of the flight log as RTH is initiated and the AC adjusts its course in doing so it flies nearly parallel the wind.
The pink line is the wind direction, the blue line is the last known heading as the AC was turning, the red line is the RTH path, and the yellow line is my estimated drift route.

Sorry, (especially to sar104 whose patience I'm sure is being tried) I'm not intending to be annoying, I've just been thinking about this event a lot and coming up with new explanations to experiment with.

 

[sar104]

My calculations were based mostly on conditions in your second log being the same or similar as in the first log. As Sar104 has pointed out, the difference between the two logs is substantial enough to make my estimate impractical.
Just to add my opinion though, at the end of the second log, the wind was coming from the SW blowing towards the NE. The AC was drifting NE with the wind and entered RTH mode. At that point it started to adjust its course to head home, in so doing, it was flying roughly parallel the wind instead of fighting almost directly against it.That is one reason I believe it was able to gain some distance at the end of the second log. If the log had shown the last 25 degrees of rotation onto the RTH path, it would have been going nearly dead into the wind which I believe would have continued to blow it along my predicted line. I don't know, in RTH mode can the AC pitch farther than it was when it was just trying to position hold? You also dropped in altitude which could totally kill my theory...

Anyway, this image shows the last few seconds of the flight log as RTH is initiated and the AC adjusts its course in doing so it flies nearly parallel the wind.
The pink line is the wind direction, the blue line is the last known heading as the AC was turning, the red line is the RTH path, and the yellow line is my estimated drift route.
View attachment 35367
Sorry, (especially to sar104 whose patience I'm sure is being tried) I'm not intending to be annoying, I've just been thinking about this event a lot and coming up with new explanations to experiment with.

But as you pointed out, it's last recorded track (your blue line) was on a heading of 337°. It was successfully making slow headway against the wind, so why do you think it would have stopped making headway and drifted NE again?

 

[MavicCF]

But as you pointed out, it's last recorded track (your blue line) was on a heading of 337°. It was successfully making slow headway against the wind, so why do you think it would have stopped making headway and drifted NE again?

When the log cut out, it was still moving parallel to the wind and (I think) was still aligning to the RTH path (red line) once it was aligned with the RTH path, it would have been on almost the same heading as when it was drifting, only facing into the wind vs trying to position hold facing away.

 

[MavicCF]

Again sorry, I'm sure you're right, I just have questions and want to learn from this.

 

[sar104]

Again sorry, I'm sure your right, I just have questions and want to learn from this.

Nothing to apologize for. The aircraft was turning left at the end to align with the RTH heading. If you compare course and speed in the second log, you get the following:



Its course at the end is -113°, and it makes sense that it was coming around to a course of -137° which would be a direct line to the HP. It's speed was increasing, most likely because it was descending, although still only 1.3 m/s. It seems probable, based on that, that it would have continued slow but measurable progress on the 137° course.

If we bound the speed in the 1 - 3 m/s range and look at where that takes it, based on battery drain rate to autolanding (10%):



That gives a range of possible distances as shown by the green, red and orange segments below:



Had it managed much over 3 m/s it should have got home, but my guess is in the 1 - 2 m/s range, in which case it may be on land.

 

[MavicCF]

Nothing to apologize for. The aircraft was turning left at the end to align with the RTH heading. If you compare course and speed in the second log, you get the following:

View attachment 35373

Its course at the end is -113°, and it makes sense that it was coming around to a course of -137° which would be a direct line to the HP. It's speed was increasing, most likely because it was descending, although still only 1.3 m/s. It seems probable, based on that, that it would have continued slow but measurable progress on the 137° course.

If we bound the speed in the 1 - 3 m/s range and look at where that takes it, based on battery drain rate to autolanding (10%):

View attachment 35381

That gives a range of possible distances as shown by the green, red and orange segments below:

View attachment 35380

Had it managed much over 3 m/s it should have got home, but my guess is in the 1 - 2 m/s range, in which case it may be on land.

Well that gives me a lot to chew on and answers the questions I had in mind. Thanks! Hopefully it will also give the OP a better idea of where to look. I admit it did seem like it had enough speed going at the lower elevation to make headway. Thanks for your patience and willingness to teach! All this will definitely keep me busy digesting for a few days.-CF

 

[RayOZ]

Unless there's input from pilot, RTH will maintain altitude, so it wouldn't have gone lower than last recorded altitude(?). Just to add a bit more uncertainty, there's wind and there's wind gust.

 

[sar104]

Unless there's input from pilot, RTH will maintain altitude, so it wouldn't have gone lower than last recorded altitude(?). Just to add a bit more uncertainty, there's wind and there's wind gust.

Agreed.