Hi all,, I had a scary experiance iwth my MM2 2 days ago, and wanted to share and see if anyone can make some sense to it.

so it was a bit winday day, takeing arial fotage of an open site, checked everything thing was OK before take off:

12:56 Take off (20 Sats) (40% Battery)
13:01 Lost GPS (0 Sats) (15% Batt) (100 meters away) (140m elevation)
13:03 regained GPS (15 Sats) (12% Batt) (300 meters away)

at that moment my friends saw the drone just sprinting to the right on a straigh line at full speed and I was not able to see it or see its direction to get it back.

when I was able to see it, it was in force landing at 5% and was able to walk to its landing spot to hand land it (avoid landing on sand)

Any idea what might've caused this?

I have the .csv file but I'm not sure if I can get any reasons for that from the log.

oh I was only able to use the "Land" option and no RTH. I pressed the RTH on the remote and it was on force landing mode.

Fly Away

Thanks all

Any idea what might've caused this?
I have the .csv file but I'm not sure if I can get any reasons for that from the log.
Perhaps if you saher that csv file, someone might be able to find what happened.
But without any data, there not much chance.

when I was able to see it, it was in force landing at 5% and was able to  walk to its landing spot to hand land it (avoid landing on sand)
oh I was only able to use the "Land" option and no RTH. I pressed the RTH on the remote and it was on force landing mode.
Once the battery is that low, there's no other option.
You would prefer the drone autolanded safely, rather than to allow you to cancel and try to fly back only to have it fall from the sky because the battery hit zero %.

Thanks @Labroides,,

I am not sure if the log will show anything as it only stated the numbers

height_sonar(meters)                                         speed(km/h)                             distance(meters)                        satellites        gpslevel                       voltage(v)
9.7                                                                                0                                            97.9144                                     21                        5                        7.258
9.7                                                                                0                                            97.9212                                     10                       4                          7.258
9.7                                                                                0                                           97.9267                                     10                            4                        7.258
9.7                                                                                0                                       97.9285        0                                     0                         0                         7.258
9.7                                                                                0                                           97.9292                                      0                         0                         7.258

if theres another log I can look it up

for the Battery force landing I know that, but the issue is the fly away happened when I have the drone near me to land it , and the fly away drained it on a very bad time

Cheers
Hasan

Hi,

Best to get help is to upload your flightlog, use this > https://www.phantomhelp.com/LogViewer/Upload/

or put a cloud-link to your flightlog on here.

cheers
JJB

JJB* Posted at 2-21 06:10
Hi,

Best to get help is to upload your flightlog, use this > https://www.phantomhelp.com/LogViewer/Upload/

https://app.airdata.com/share/sVHYRB

Here’s a link on AirData. Is it the same as phantomhelp?

Thanks.

hhasanain Posted at 2-21 06:37
https://app.airdata.com/share/sVHYRB

Here’s a link on AirData. Is it the same as phantomhelp?

Hi,

Had a look at your flight.

At 4m16s at 235 meters away from home (19% batt level) craft in  RTH due to low battery, enough batt left to reach home...At 4m34s you did cancel RTH at 110 meters from HP with 17% batt.

Into PANO mode and after that into ATTI at 5m25s, bc satellites numbers to zero!
Satellites back on at 5m56s at 129 meters with 12% batt level left.
At 6m1s into RTH but at this stage battery level is not enough to reach home.
At 6m31 into Autolanding to land safely from height 131 meters on the ground.

So what went wrong for you.....do not cancel RTH at low batt levels!

HAve no idea why satellites dropped to zero, thus ATTI mode.

But in autolanding it is still possible to fly forward....if you had pushed forward all the time my guess is that your Mini2 had made home...See the last chart   for distances    the gap is not that big....

cheers
JJB

JJB* Posted at 2-21 06:54
Hi,

Had a look at your flight.

Great job explaining and it’s also never good to take off with a battery not fully charged

RenegadeCowboyAZ Posted at 2-21 10:51
Great job explaining and it’s also never good to take off with a battery not fully charged

Thanks,

i agree, best to start with a 100% battery. But it all depends what the intention is of the flight, wich i did not know, so no comment on that.Well, it is so easy to say that pilots make "stupids" mistakes, i just try to explain.

If in this case the first RTH was not cancelled than his drone would have had a happy landing.

cheers
JJB

JJB* Posted at 2-21 11:21
Thanks,

i agree, best to start with a 100% battery. But it all depends what the intention is of the flight, wich i did not know, so no comment on that.Well, it is so easy to say that pilots make "stupids" mistakes, i just try to explain.

Totally agree with you about the RTH

Thank you @JJB, and all,,

I will make sure that 100% is my take off battery,, and I think that the GPS loss may be because of the low voltage with the low batt.

I will look at the analysis again and see what I can learn

Cheers all

hhasanain Posted at 2-21 21:36
Thank you @JJB, and all,,

I will make sure that 100% is my take off battery,, and I think that the GPS loss may be because of the low voltage with the low batt.

I think that the GPS loss may be because of the low voltage with the low batt.
From 320 seconds to 351 sec the number of sats reported by your drone dropped from 22 to zero.
From 351 seconds the number gradually increased.

The satellite numbers came back to 20 at 356 sec and the flight controller reported that GPS data was reliable at 361 sec.
GPS remained good until the end of the flight at 450 seconds.

The reason for loss of GPS is a mystery.
It was not related to battery level and at 1% battery the GPS would still work properly.
There is normally no reason for loss of GPS reception like this.
It looks similar to GPS jamming that I've seen in a few flight records from Russia but I can't be sure that was the cause in this case.
If you see it again, try descending and see if there is any change.

hhasanain Posted at 2-21 21:36
Thank you @JJB, and all,,

I will make sure that 100% is my take off battery,, and I think that the GPS loss may be because of the low voltage with the low batt.

Hi,

Its my pleasure to help.

Don`t know why you think you had low cell voltages, both cells > 3.3 volts wich is in general a min value for a mini.

Batt values > 3.6 volts during GPS zero time.
Plus low battery has no effect on GPS module, even on low and very low values GPS signals are received.
cheers
JJB

I know there may be situations where you know you won't need much battery to get a quick shot of something, but one of my pre flight checklist items is to make sure I have the battery fully charged at takeoff.  There are too many unknowns while out flying that could cause a flight to take longer than anticipated, or the battery to drain quicker than usual.  I'm not going to bash you for not having much battery at takeoff (to each their own), but that's my two cents.