Forced landing over water: Never trust Battery %
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4868 65 2020-6-17
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trader6777
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Almost lost my mini today.  RTH was activated at 73% remaining.


2020-6-17
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Visual Air
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That was a close one glad you made it.
2020-6-17
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jonny007
Second Officer
Germany
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Why not trust the battery indicator? RTH at 68% doesn't mean that that's enough for the same way back. Especially not when there is headwind on the return flight.
2020-6-17
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ABeardedItalian
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This is clearly operator error and not the fault of the mini, you were flying against the wind on the return causing the mini to use more power thus draining the battery quicker. Know the wind conditions before attempting something like this again, you might not be so lucky the next time.


Glad to see you made back safely, but you could of easily lost your mini.
2020-6-17
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TDZHDTV
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Warnings and messages are there to keep your Mini safe, why on earth didn’t you turn back when you got weak signal warning or at the very least lower your altitude?
2020-6-17
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trader6777
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ABeardedItalian Posted at 6-17 09:55
This is clearly operator error and not the fault of the mini, you were flying against the wind on the return causing the mini to use more power thus draining the battery quicker. Know the wind conditions before attempting something like this again, you might not be so lucky the next time.

The video skips ahead, if you look closely RTH was activated at 73%.  So it used up 25% battery going out and 68% battery on the way back, that's a difference big enough to say, don't rely on the battery % to get back safely.   Also, I did my homework before I took off, wind was rated at 3.5 mph, at 380 ft, I'm pretty sure that was even close to accurate.

Bottom line, not operator error, battery % gave a false sense of security to fly out that far.
2020-6-17
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trader6777
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TDZHDTV Posted at 6-17 10:07
Warnings and messages are there to keep your Mini safe, why on earth didn’t you turn back when you got weak signal warning or at the very least lower your altitude?

I will pay more attention to the warning in the future, because apparently, battery % remaining doesn't mean sheet.  RTH at 73% should have been plenty of cushion.
2020-6-17
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JJB*
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Why did the MM dit not RTH after 10 seconds?  as in 1m17 second in this video
2020-6-17
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trader6777
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JJB* Posted at 6-17 10:38
Why did the MM dit not RTH after 10 seconds?

I cancelled  RTH when the video went blank.  My plan was, try for 15,000 ft, if I didn't hit it by 65% remaining, I would turn back.
2020-6-17
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Andy Uk
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trader6777 Posted at 6-17 10:18
I will pay more attention to the warning in the future, because apparently, battery % remaining doesn't mean sheet.  RTH at 73% should have been plenty of cushion.

Upload your flight data to AirData and you'll get more info back. Suspect it is headwind though what mode did you flight out using?
2020-6-17
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trader6777
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Andy Uk Posted at 6-17 10:41
Upload your flight data to AirData and you'll get more info back. Suspect it is headwind though what mode did you flight out using?

Sport mode both ways.  I admit it was a mistake not lower altitude though.  The 3.5mph wind rating was for ground level and I need to keep that in mind for the future.
2020-6-17
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JJB*
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trader6777 Posted at 6-17 10:40
I cancelled  RTH when the video went blank.  My plan was, try for 15,000 ft, if I didn't hit it by 65% remaining, I would turn back.

ok, what happend to your phone?  the Aircraft oreintation indicator turns red after while

and your mobile device compass is wrong or you have to turn your device 180 in the holder.

cheers
JJB
2020-6-17
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Andy Uk
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trader6777 Posted at 6-17 10:43
Sport mode both ways.  I admit it was a mistake not lower altitude though.  The 3.5mph wind rating was for ground level and I need to keep that in mind for the future.

Big wind coming back then.  Don't trust wind forecasts look at your speeds at you alt and if you aren't getting what you expect bear that in mind.  You also kept pushing it well after the intial disconnect
2020-6-17
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A J
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Bit of a nail biting finish there - glad you managed to get it back just in time. Word to the wise - if conducting long range test flights in future always fly outbound into the wind then return with the wind speed carrying the drone (though wind direction can change). That will typically increase your air speed to be faster on the return journey and note that the drone does not take wind speed into account when assessing the telemetry to initiate low battery RTH. You were very, very lucky not to have lost it!
2020-6-17
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3Recon
Second Officer
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I know we've been in isolation for a long time but, testing out alt. and fight distance over water oh well but losing contact with phone!. The Mini lives to fly again. Give it a pat on it's back. it'll soar again. Enjoy
2020-6-17
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Labroides
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Your big mistake was not understanding wind or your drone and thinking that a forecast is what the wind will actually be.
It's very easy to check wind speed and strength before you fly.
Wind will always be stronger up high.

The Mini gets 29 mph in Sport Mode in still air.
You were getting 18 mph.
That's telling you that you are fighting a 10 mph headwind up there.
And you stayed up high where the wind is stronger !!

If you're planning to go far, it's not a good move to fly downwind going out and force the drone to fight a headwind coming home.

2020-6-17
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m80116
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Also to be noted: the -battery level is low- notice has been disregarded. It's dynamic and can happen even with an almost full battery as it computes the distance the AC has to travel back to the homepoint.
2020-6-17
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22340179
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Don't do a range test in Sport mode. It uses more power. Weird how it lost so much power so quickly though, glad you didn't lose it. Would have been a stressful flight back to land heh.
2020-6-17
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trader6777
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22340179 Posted at 6-17 15:03
Don't do a range test in Sport mode. It uses more power. Weird how it lost so much power so quickly though, glad you didn't lose it. Would have been a stressful flight back to land heh.

flying at a lower altitude is defiantly more efficient due to lower wind, but sport mode vs P mode... I don't think there's a notable difference in efficiency.  Do you have a data to back that up?
2020-6-17
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22340179
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trader6777 Posted at 6-17 16:05
flying at a lower altitude is defiantly more efficient due to lower wind, but sport mode vs P mode... I don't think there's a notable difference in efficiency.  Do you have a data to back that up?

It's tried and tested. Heaps of videos on youtube have a look. It uses more power over all over long distances.
2020-6-17
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Paulaleroux
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I always wondered how folks got those shots.  Did you get that video from your Mavic Mini?  or were you recording your mobile phone screen?
2020-6-17
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trader6777
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Paulaleroux Posted at 6-17 17:08
I always wondered how folks got those shots.  Did you get that video from your Mavic Mini?  or were you recording your mobile phone screen?

Used the screen recorder that comes built into every iphone.  Video from the SD card is higher quality but won't display the flight data.
2020-6-17
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Daniella3d
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trader6777 Posted at 6-17 17:16
Used the screen recorder that comes built into every iphone.  Video from the SD card is higher quality but won't display the flight data.

Not every Iphone. I don't have it on my Iphone 6.
2020-6-17
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trader6777
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Daniella3d Posted at 6-17 17:55
Not every Iphone. I don't have it on my Iphone 6.

Nope, every iphone has it.  Here are instructions if it's not enabled on your phone:
2020-6-17
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Daniella3d
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I think you must have ios 11 installed. hmm I never upgraded my firmware. Last phone I did the upgrade, then it started calling every one on my contact list in the middle of the night, ramdomly.
2020-6-17
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22340179
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Daniella3d Posted at 6-17 19:09
I think you must have ios 11 installed. hmm I never upgraded my firmware. Last phone I did the upgrade, then it started calling every one on my contact list in the middle of the night, ramdomly.

Upgrading the ios on older devices can slow down older devices also. I have an old ipad mini that is basically useless because I updated it. Apple do it on purpose so you buy a new device.
2020-6-17
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GaryDoug
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I think your title of this topic is perfect. Might not be for the reason you thought though ;-)
2020-6-17
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Geebax
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I think you were very brave doing a 15,000 foot flight out over water in a Mavic Mini, given all the shortcomings and issues the mini has.
2020-6-17
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DAFlys
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Very odd. pleased you got it back.  
2020-6-18
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ThalisGr
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Glad you had your drone back. Not sure why you tried to fly it so far away though. I understand it was a test but what's the point?
2020-6-18
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Daniella3d
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22340179 Posted at 6-17 20:10
Upgrading the ios on older devices can slow down older devices also. I have an old ipad mini that is basically useless because I updated it. Apple do it on purpose so you buy a new device.

Yes they do it on purpose. We had 2 Iphone 5 and after upgrading to the new firmware, one of the phone started calling people ramdomly in middle of the night (not even during the day!) and then we replaced that phone thinking it was broken, then we upgraded the other Iphone 5 and it did the same exact thing, starting to call people on it's own in the middle of the night. They had removed the button to desactivate Siri as well, so no way to stop the phone from this programmed obsolete. I did a jailbreak and that took care of it! lol! Apple are crooks, now I do not upgrade the firmware at all unless it is absolutely necessary to install programs and I do a jailbreak instead of using the Apple firmware.
2020-6-18
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Daniella3d
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Geebax Posted at 6-17 22:13
I think you were very brave doing a 15,000 foot flight out over water in a Mavic Mini, given all the shortcomings and issues the mini has.

I though the same thing. You were very very lucky to get your drone back. Amazing luck that everything went so well despite the 15,000' distance and the strong winds. That's amazing.

Like someone else said, it's always better to start the flight going against the wind, so when returning the drone it is going to be in the same direction as the wind and not fight it.
2020-6-18
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BigBird-2
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Now that had me sitting on the edge of my chair. Glad you made it back safely.
2020-6-18
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stuka75
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I wonder if that battery is at risk since it was nearly depleted to 0? Unless DJI has more battery capacity cushion that doesnt show on meters.
2020-6-18
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Zen Fly
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stuka75 Posted at 6-18 19:50
I wonder if that battery is at risk since it was nearly depleted to 0? Unless DJI has more battery capacity cushion that doesnt show on meters.

0 it's about max low level of discharge no 0v.
2020-6-18
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Guorium
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trader6777 Posted at 6-17 16:05
flying at a lower altitude is defiantly more efficient due to lower wind, but sport mode vs P mode... I don't think there's a notable difference in efficiency.  Do you have a data to back that up?

The data is all over the place online. It is commonly accepted that lithium batteries dissipate more stored energy as waste heat when working at higher power output, for example pushing hard against strong wind on S mode instead of lowering attitude and use P mode.
2020-6-18
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Ice_2k
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trader6777 Posted at 6-17 10:14
The video skips ahead, if you look closely RTH was activated at 73%.  So it used up 25% battery going out and 68% battery on the way back, that's a difference big enough to say, don't rely on the battery % to get back safely.   Also, I did my homework before I took off, wind was rated at 3.5 mph, at 380 ft, I'm pretty sure that was even close to accurate.

Bottom line, not operator error, battery % gave a false sense of security to fly out that far.

Sorry man, your drone's speed on the way back shows 13-14 mph head wind. 100% user error, you're blaming the drone for no good reason. Also, seems really weird to ignore the battery warning (the drone notified you when you should start heading home) and then, when it turns out the drone was correct all along, conclude that you should never trust battery percentage
2020-6-19
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AE1M
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Looks like it worked perfectly, what’s your gripe?  You pushed your bird to the limit.
2020-6-19
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Nolan Silvius
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I almost lost my mavic air 2 over water...but that was due to pilot error I ignored the low battery warnings and it started to land itself over water.
2020-6-19
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Daniella3d
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Canada
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Nolan Silvius Posted at 6-19 04:25
I almost lost my mavic air 2 over water...but that was due to pilot error I ignored the low battery warnings and it started to land itself over water.

is it possible to cancel an autolanding over water?
2020-6-19
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