Help! My Mavic Mini is like Rhett Butler: Gone With the Wind

[Daddystu]

Hi,

I'm hoping to get some help understanding my flight info from everyone here more knowledgeable than myself. I lost connection to my Mini and RTH wouldn't work because of strong winds. It didn't seem strong on the ground, but at altitude it was apparently. Find My Drone on the app shows its last reported location, but still at 94 ft altitude. It also shows a last photo the drone took on its own, but that location is actually 450 feet north and 40 seconds earlier, so I'm not sure why it does that. Another user told me his drone flew another 3 minutes after its last location, so mine could be anywhere if the same happened here. The last little bit of the flight path seems to show a U turn. I thought this might be a spiral to the ground as it lost power, but the reported altitude never changed. I've searched the area but its also heavily wooded. It appears it was drifting due south with the wind, so I also searched along a projected path, also heavily wooded. Does it make sense it would stop reporting and completely shut down at 17% battery? Or did it stop reporting to use powers for the motors and continue flying, or emergency land? Any ideas on where I should search?

Any help is appreciated. Hopefully the link works to the data.

 

[eEridani]

Didn't you hear all of the strong wind land immediately warnings?

Here's three that started in the first 30 seconds of flight. The second one says the drone can't hold position and is drifting.

Strong wind warning. Aircraft unable to return to home automatically. Lower altitude immediately and return to home manually (Code: 30149).

Not Enough Force/ESC Error. Medium severity, more serious safety impactStrong wind warning. Aircraft unable to return to home automatically. Lower altitude immediately and return to home manually (Code: 30149).

Aircraft max power load reached. Decrease altitude and fly with caution. If this issue persists, land immediately (Code: 30168). Decrease altitude and fly with caution.

 

[Meta4]

Hi,

I'm hoping to get some help understanding my flight info from everyone here more knowledgeable than myself. I lost connection to my Mini and RTH wouldn't work because of strong winds. It didn't seem strong on the ground, but at altitude it was apparently.

If you look at data from 4:26, the drone was hovering at 72 ft and having trouble holding position.
The pitch & roll data show angles of around 20° showing that the drone was fighting hard to resist the wind.

Later at 8:38.5 with the drone about 80 ft up, the drone hovering and trying to hold position, was being blown south at 2-8 mph by gusty winds.

The data is full of numerous warnings that advise:
Not Enough Force/ESC Error. Strong wind warning. Aircraft unable to return to home automatically. Lower altitude immediately and return to home manually (Code: 30149). Return to home and land promptly. If any of the propellers are warped, restart the ....
These indicate that your props weren't providing as much thrust as they should and would have reduced the drone's ability to push against the wind.
As these warnings became more common, the drone pitched/rolled less than it should have, further reducing it's ability to fight wind.

You flew or allowed the drone to get further and further south without making any serious effort to bring it back.
The battery reached 40% with the drone >1000 ft downwind.
Still no effort to bring it back.
You seemed to be doodling around, flying this way and that for a few seconds and going nowhere, but the drone slowly drifting further south.

At 12:40 you received warnings of low battery level (31%).
It was 80 ft up, 1300 ft away and hovering but being blown south at 1-5 mph.
Eight seconds after receiving the low battery warning, you initiated RTh and left the drone to find it's own way home.
It climbed to the set height of 100 ft where the wind was even stronger.

RTH pitch angles were not enough to push against the wind and the drone was now blowing backwards at 6-10 mph while trying to fly north.
At 20% you tried giving some joystick input for more speed, but because of the propeller problems, the drone continued slowly southwards.
At 14:37 you cancelled RTH and resumed control.
But you left it 100 ft up.
But even at full stick the drone continued to be blown further south at 4-8 mph.

At 14:57 the signal was lost with the drone 93 ft up and still being blown backwards with the battery level at 17%.

On losing signal, it will have continued to RTH and been blown further south until it reached critical low voltage when it will have autolanded.

 

[Meta4]

The last little bit of the flight path seems to show a U turn.

I'm not sure why Airdata shows that as the data does not support it.
Every 1/10th of a second the location data is further south than the previous line of data.

I've searched the area but its also heavily wooded. It appears it was drifting due south with the wind, so I also searched along a projected path, also heavily wooded.

The drone will be further south as it willl have attempted (and failed) to RTH until reaching critical low voltage.

Does it make sense it would stop reporting and completely shut down at 17% battery? Or did it stop reporting to use powers for the motors and continue flying, or emergency land? Any ideas on where I should search?

Neither. Data was only lost because the drone was out of signal range.
You made several critical mistakes that cause the loss of the drone.
You ignored warnings about propeller/thrust problems.
You flew downwind in a strong wind, which meant a fight against a headwind to come home.
You didn't seem to understand that the wind would be stronger up higher.
You went much too far before trying to bring it home.

 

[MAvic_South_Oz]

..

My Mavic Mini is like Rhett Butler: Gone With the Wind​

Frankly my dear, I don't give a . . . oh hang on, you can't say that word with out some ****'s.

Seriously now . . . I feel the OP knows he mucked up.

At this stage, it'd be nice to get a location estimate for the OP, possibly @slup @sar104 or such could try their magic projections for the new member ??

Welcome to the forum @Daddystu . . . hopefully soon you will see some good estimates of a location to search.

 

[Daddystu]

I'm not sure why Airdata shows that as the data does not support it.
Every 1/10th of a second the location data is further south than the previous line of data.

The drone will be further south as it willl have attempted (and failed) to RTH until reaching critical low voltage.

Neither. Data was only lost because the drone was out of signal range.

You made several critical mistakes that cause the loss of the drone.
You ignored warnings about propeller/thrust problems.
You flew downwind in a strong wind, which meant a fight against a headwind to come home.
You didn't seem to understand that the wind would be stronger up higher.
You went much too far before trying to bring it home.

I'm not sure why Airdata shows that as the data does not support it.
Every 1/10th of a second the location data is further south than the previous line of data.

The drone will be further south as it willl have attempted (and failed) to RTH until reaching critical low voltage.

Neither. Data was only lost because the drone was out of signal range.

You made several critical mistakes that cause the loss of the drone.
You ignored warnings about propeller/thrust problems.
You flew downwind in a strong wind, which meant a fight against a headwind to come home.
You didn't seem to understand that the wind would be stronger up higher.
You went much too far before trying to bring it home.

Meta4, thanks so much for your analysis. I don't even understand where you are finding all of this data. It's true I made critical mistakes and ignored the warnings. There is always a breeze here (I'm near Kitty Hawk, after all) so I get those warnings a lot. I was over confident. I will apply many new lessons to my next drone, believe me. But I didn't fly south intentionally at all. I was fumbling around trying to regain control because the connection kept dropping. After about 11 minutes, I had no idea where it was. Based on everything you are seeing, with 17% remaining battery do you have any idea how much longer it would have been airborne before it would have attempted landing due to critical low voltage? Any idea how much farther south it could have traveled, not accounting for significant wind gusts?

 

[Daddystu]

..

My Mavic Mini is like Rhett Butler: Gone With the Wind​

Frankly my dear, I don't give a . . . oh hang on, you can't say that word with out some ****'s.

Seriously now . . . I feel the OP knows he mucked up.

At this stage, it'd be nice to get a location estimate for the OP, possibly @slup @sar104 or such could try their magic projections for the new member ??

Welcome to the forum @Daddystu . . . hopefully soon you will see some good estimates of a location to search.

Thank you, sir. You are a gentleman and a scholar.

 

[Meta4]

Based on everything you are seeing, with 17% remaining battery do you have any idea how much longer it would have been airborne before it would have attempted landing due to critical low voltage? Any idea how much farther south it could have traveled, not accounting for significant wind gusts?

The wind was so variable I wouldn't like to make an estimate.
Perhaps @slup would when he shows up.

 

[MAvic_South_Oz]

They must be sleeping !
Soon arrive here I hope.

 

[Gagey52]

Welcome to the forum from the outback of Australia. Sorry for you loss, an expensive less there.
Regards

 

[slup]

...Any ideas on where I should search?

Made some quick calculations ... but as said earlier, the drift speed was very inconsistent & varied between actually doing some progress towards the HP & drifting away at approx 17mph. The tilt direction for the Mini when fighting the wind was fairly consistent though ... so the compass direction it blew away can some what be trusted. The drift compass direction was in the end of the log 178,7 degrees.

Here all relevant Telemetry out from the log ... check the legend under the chart for what the graphs show & the values there is from the very end of the log. (all white background fields is RC-Mini disconnects & nothing is recorded in the log, the blue is P-mode & pink RTH)

(Click on the chart to make it larger)

This is the very roughly estimated path your Mini took after the final disconnect ... the first circle is where the low battery auto landing would have started from a height of approx 94ft (the whole area there is mainly flat & on the same height as the HP) with a descend speed of 1,8m/s ... continuously drifting with an average speed of 8mph.

The second circle is where it would have touched down pure theoretically (if not hitting something when lower over ground). GPS positions where you lost connection & where it might have touched down in the pic. All of this is very rough ... this as the drift speed changed a lot + that your Mini, due to the flattened props also had a hard time to keep the height ... this condition could after the disconnect developed to a uncommanded descent where the props no longer could keep the Mini airborne ... in that case it would have descended down earlier.

(Click on the picture to make it larger)

I'm not sure why Airdata shows that as the data does not support it.
Every 1/10th of a second the location data is further south than the previous line of data.

You actually have a slight & short progress towards the HP just there in the end ... it's also a shorter disconnect there which change the drawn path in Airdata & PhantomHelp some ... the Mini makes approx. 13,2ft progress which correlates to a change in the forth decimal in Latitude ... & that you have in the log, but if this is real or just variances in the GPS accuracy?

 

[Daddystu]

Made some quick calculations ... but as said earlier, the drift speed was very inconsistent & varied between actually doing some progress towards the HP & drifting away at approx 17mph. The tilt direction for the Mini when fighting the wind was fairly consistent though ... so the compass direction it blew away can some what be trusted. The drift compass direction was in the end of the log 178,7 degrees.

Here all relevant Telemetry out from the log ... check the legend under the chart for what the graphs show & the values there is from the very end of the log. (all white background fields is RC-Mini disconnects & nothing is recorded in the log, the blue is P-mode & pink RTH)

(Click on the chart to make it larger)View attachment 142679

This is the very roughly estimated path your Mini took after the final disconnect ... the first circle is where the low battery auto landing would have started from a height of approx 94ft (the whole area there is mainly flat & on the same height as the HP) with a descend speed of 1,8m/s ... continuously drifting with an average speed of 8mph.

The second circle is where it would have touched down pure theoretically (if not hitting something when lower over ground). GPS positions where you lost connection & where it might have touched down in the pic. All of this is very rough ... this as the drift speed changed a lot + that your Mini, due to the flattened props also had a hard time to keep the height ... this condition could after the disconnect developed to a uncommanded descent where the props no longer could keep the Mini airborne ... in that case it would have descended down earlier.

(Click on the picture to make it larger)
View attachment 142680

View attachment 142681


You actually have a slight & short progress towards the HP just there in the end ... it's also a shorter disconnect there which change the drawn path in Airdata & PhantomHelp some ... the Mini makes approx. 13,2ft progress which correlates to a change in the forth decimal in Latitude ... & that you have in the log, but if this is real or just variances in the GPS accuracy?

View attachment 142685

View attachment 142686

Thank you very much, Slup! This is amazing, even though I hear you saying this is only a rough estimate due to the varying conditions. I searched along this direct path and even in the clearing where the yellow thumbtack is, but it is very rough and could be anywhere out there in the trees. It is rarely traveled; the Mini will remain there untouched for 20 years unless I can find it. Thankfully I have learned this on a Mini before I upgrade to something more expensive. Based on your analysis, how much of an east-west variance along the arc should I look? The recorded drift appears to be pretty much due south, but looks to my untrained eye like it might have deviated very slightly more to the east for the last 370 feet of data.



And for my own edification, at which point in the protocol would the emergency landing be initiated? When the battery reaches 5%? At 10%? And when it loses RC contact, it will continually try to return home? I thought because winds were too strong at the RTH altitude of 100 ft, it was no longer trying to return home on its own.

Thanks!

 

[slup]

...Based on your analysis, how much of an east-west variance along the arc should I look? The recorded drift appears to be pretty much due south, but looks to my untrained eye like it might have deviated very slightly more to the east for the last 370 feet of data.

It's nearly impossible to say when we have these very inconsistent data to go on ... but to give you a sense what a slight deviation of just 10 degrees from the last indicated drift direction will do to the search areas width at the calculated touch down distance ... Have below added 2 yellow lines, each +/-10 degrees from the red in the middle. The width at that distance is a tad above 490ft. And as you see ... the further your Mini might have drifted the broader the area will be. And to this add in the distance uncertainty. All will create a huge search area where a small Mini nearly can be stepped on without seeing it.

...at which point in the protocol would the emergency landing be initiated?

The critical low battery forced auto landing percentage is height dependent ... it will start to land at higher percentages the higher you fly, this so it have enough juice to reach ground before totally empty & starts to free fall. In your case the Mini was at a 94ft height ... which meant that the landing started as soon as your battery turned over to 6%, check the black graph in the chart.

...And when it loses RC contact, it will continually try to return home? I thought because winds were too strong at the RTH altitude of 100 ft, it was no longer trying to return home on its own.

If your failsafe setting in the DJI FLY app is set to RTH (which it was) ... your Mini will initiate RTH when it loses the RC connection. But if the maximum air speed your Mini can achieve is lower than the headwind speed it will be blown backwards constantly fighting ... this will go on until the critical low battery auto landing have landed your Mini. By looking at the last RTH phase in the log where you didn't made any stick commands it's possible to interpolate the battery consumption ... Your mini consumed approx. 1% each 9,6sec.

 

[Daddystu]

It's nearly impossible to say when we have these very inconsistent data to go on ... but to give you a sense what a slight deviation of just 10 degrees from the last indicated drift direction will do to the search areas width at the calculated touch down distance ... Have below added 2 yellow lines, each +/-10 degrees from the red in the middle. The width at that distance is a tad above 490ft. And as you see ... the further your Mini might have drifted the broader the area will be. And to this add in the distance uncertainty. All will create a huge search area where a small Mini nearly can be stepped on without seeing it.

View attachment 142722


The critical low battery forced auto landing percentage is height dependent ... it will start to land at higher percentages the higher you fly, this so it have enough juice to reach ground before totally empty & starts to free fall. In your case the Mini was at a 94ft height ... which meant that the landing started as soon as your battery turned over to 6%, check the black graph in the chart.


If your failsafe setting in the DJI FLY app is set to RTH (which it was) ... your Mini will initiate RTH when it loses the RC connection. But if the maximum air speed your Mini can achieve is lower than the headwind speed it will be blown backwards constantly fighting ... this will go on until the critical low battery auto landing have landed your Mini. By looking at the last RTH phase in the log where you didn't made any stick commands it's possible to interpolate the battery consumption ... Your mini consumed approx. 1% each 9,6sec.

Thanks for that extra knowledge! I'll head out to take another look soon. I guess with these winds, there was virtually no chance it would have made any progress towards HP after it stopped reporting, and if it had come back into range it would have reported that, too.

 

[MAvic_South_Oz]

Thankfully I have learned this on a Mini before I upgrade to something more expensive.

Well , the good thing there is you will have a much easier time in those sort of winds with a larger model, and less chance of a loss on this same circumstance.
Comparative max wind recommendations for all DJI model models are online.
All the best for your future drone experiences.

 

[Capt KO]

Be sure to mark your next drone with a ph#. They do return..eventually

 

[eEridani]

Thanks for that extra knowledge! I'll head out to take another look soon. I guess with these winds, there was virtually no chance it would have made any progress towards HP after it stopped reporting, and if it had come back into range it would have reported that, too.

If it made any progress it would have been single digit mph. More likely it went into fight the wind mode, and lost the battle until the battery died.

I'd start looking for the drone where the signal was lost, then trend downwind. I wouldn't expect it to be too far away -- my guess is it was drifting as much as 7.2 mph but part of me thinks you were "helping" the drift with control input - and that "help" went away when the RC disconnected.

 

[Daddystu]

All hail, King Slup! With his expert analysis (and a lot of luck, for sure), after a couple hours of searching outward from the first circle, I found my drone safely nestled in the tall grass. Not even a hard landing!





The actual location was just beyond the projected drop zone, which could have easily been pushed by the wind gusts.

This was over 1,500 ft from its last known position.


I haven't fired it up yet, but everything seems to be in order, but I might need to replace some props.

Thanks to everyone for your support!

 

[Daddystu]

If it made any progress it would have been single digit mph. More likely it went into fight the wind mode, and lost the battle until the battery died.

I'd start looking for the drone where the signal was lost, then trend downwind. I wouldn't expect it to be too far away.

View attachment 142742

I had no idea the wind speed was that high from the ground!

 

[Daddystu]

All hail, King Slup! With his expert analysis (and a lot of luck, for sure), after a couple hours of searching outward from the first circle, I found my drone safely nestled in the tall grass. Not even a hard landing!


View attachment 142740

View attachment 142741
The actual location was just beyond the projected drop zone, which could have easily been pushed by the wind gusts.

This was over 1,500 ft from its last known position.
View attachment 142743

I haven't fired it up yet, but everything seems to be in order, but I might need to replace some props.

Thanks to everyone for your support!

This puts the total distance from the HP at over 4,250 feet (1.3 km).