GavinThin Posted at 2-2 06:14
Hi JJB, Thanks for the reply.

I think if it's automatically activated then I might be.

Oke, have seen that log.

But no max height reached warnings in your log, i see 9 times a connection loss.
Plus many NotEnoughPower messages.
cheers
JJB

JJB* Posted at 2-2 06:19
Oke, have seen that log.

But no max height reached warnings in your log, i see 9 times a connection loss.

Yeap when it close to the max altitude I set, it's easy to get slow connection or connection loss.

Is the cell 1 and 2 orange numbered represented Not enough power?

davidms Posted at 2-2 05:49
Did you have payload mode enabled?

Hi Davidms,

The payload mode you mentioned is it within this panel ?

GavinThin Posted at 2-2 06:35
Yeap when it close to the max altitude I set, it's easy to get slow connection or connection loss.

Is the cell 1 and 2 orange numbered represented Not enough power?

Hi Gavin,

No problems with your battery, max deviation between the 2 cells = 17 mVolts.
Think the colouring of batt cells in PhantomHelp is not adjusted to the MM battery.

NotEnoughPower, see my chart with another presentation of your data.

cheers
JJB

GavinThin Posted at 2-2 06:53
Hi Davidms,

The payload mode you mentioned is it within this panel ?

Here

JJB* Posted at 2-2 07:23
Hi Gavin,

No problems with your battery, max deviation between the 2 cells = 17 mVolts.

Thanks a lot for the information !
Mind to share how do you view this chart?

And regarding the not enough power eror message,
it show up even if my battery level still around 76~79% ?
Hmm~

Oracle Miata Posted at 2-1 14:46
The mini can be unpredictable in cold weather.  I've seen it fly terribly, but I have also seen it fly normally in quite cold temps.

Why buy a mini?  Just make a racing quad if you want a difference from the other DJI drones that exist.  I'm about to go ham when I get my goggles from warranty in the mail.  Freestyle quadcopter.  The things you can't do w/ DJI made drones but using the DJI Ocusync Air system.

GavinThin Posted at 2-2 07:29
Thanks a lot for the information !
Mind to share how do you view this chart?

Hi Gavin,

Lot of users experience NotEnoughPower in their logs.
Supposedly using the latest firmware reduces the amount of these messages.

If MM is using lot of power, in sport mode with fully fwd and up , this is kind of 'normal'.
In Hover situations they should stay away, mayby there flying in thin air (High and hot)

DJI can tell you more about your flight.

PS at the end you lost connection, and your MM dropped height is that period.
Loosing total connection or video connection will set the MM in a RTH mode.
But flying within 20 meters away from HP (as you did), it will autoland.

Not sure if this happend in your flight, but again  DJI can tell.

My charts see this > https://forum.dji.com/thread-203659-1-1.html

Have fun with your MM and don`t  forget to do pre- (with compass check) and after take-off checks always.

cheers
JJB

davidms Posted at 2-2 07:27
Here

Got it !
Thanks, payload mode enabled !

GavinThin Posted at 2-2 07:29
Thanks a lot for the information !
Mind to share how do you view this chart?

It would be interesting to see the .DAT file which should be on you mobile device.

JJB* Posted at 2-2 07:38
Hi Gavin,

Lot of users experience NotEnoughPower in their logs.

Thanks a lot for the tips and tricks !
Will Definitely check it out.

grahamjohnson10 Posted at 2-2 07:46
It would be interesting to see the .DAT file which should be on you mobile device.

yep, but did you know that the DAT files are removed when flights are synced in the FlyApp with the DJI china server?

So if you doubt your flight, first save that DAT file before syncing....  just a small tip from a "no knowledge person"

Hi Gavin,

I'm late into this ... but have lately already seen several similar cases regarding uncommanded descents over at MavicPilots.com. Unfortunately nobody have been able to conclude what the reason is yet, we suspect some kind of fw fault in this stage.

My advise is to report this to DJI & ask them to investigate the event ... they have a much greater possibility to access more data as they can read the encrypted DAT log stored in the Mini.

All of below is harder to interpret as you used the prop guards outside ... it's a major no, no to do that as they act as sails & make the usually underpowered Mini even weaker in the slightest wind.

First just a look at the messages in the log ... the Mini was clearly under strain ...



What we have found so far that is common between all uncommanded descend cases is a sudden larger pitch movement just when the descend starts (found in the graph below were the colored markers is). Just there the drone pick up descend speed & drops fast ... this together with a flight instability. Unfortunately you lose the downlink just after the event starts & when it returns the Mini have descended 18 meters in approx 8 sec. It's there you try to act, you release the rudder and by mistake command full negative throttle shortly, change your mind & push throttle up & again start inputs to the rudder ... but everything in vain, the Mini goes down pitching wildly between +7 & -6 degrees.

This had nothing to do with the VPS sensors, temperature, wind (luckily considering the guards)  or fog ... the sensors were reporting correctly, the Mini were reported to be in "sky" so no auto landing were commanded.



If you have the possibility to provide the DAT file stored in your phone it could give us more data regarding the engines ... below how you do it (hopefully the Fly app have created it). The right one ends with FLY030.

Mobile device DAT files (DJI GO 4 & DJI Fly)​
​
The DAT file naming convention, based on the date and time of the start of the file, is: YY-MM-DD-hr-min-sec_FLYXXX.DAT., where XXX is the flight recorder file index from the HOME_dataRecorderFileIndex field in the txt log.​
​
These are retrieved by the same method as the TXT logs. Under both iOS and Android they are in a subfolder, MCDatFlightRecords, in the folder that contains the TXT logs. In some cases, for reasons not fully explained but possibly mobile-device hardware related, and most often under Android, DAT files are not created and that folder is empty. Uninstalling and reinstalling the app sometimes fixes that. One user also found that the process required manual deletion of the app folder (apparently not deleted automatically in the uninstall process) before reinstalling the app.

JJB* Posted at 2-2 07:56
yep, but did you know that the DAT files are removed when flights are synced in the FlyApp with the DJI china server?

So if you doubt your flight, first save that DAT file before syncing....  just a small tip from a "no knowledge person"

Hi JJB,

Is this under the Fly app only ... you know this for a fact?
This could explain why we have been unsuccessful to retrieve the DAT in all earlier similar cases ...

Is it possible the mini experiences vortex ring state initiated by pitch movement under hovering conditions thereby losing the ability to maintain altitude?

davidms Posted at 2-2 08:42
Is it possible the mini experiences vortex ring state initiated by pitch movement under hovering conditions thereby losing the ability to maintain altitude?

Vortex ring is caused when craft descends to quickly, it wil descend into the turbulent air created the prop down wash is creating, so I don’t think this is the reason.

Vortex ring was always only seen when descending straight down so correct way to descend should be at an angle particularly in sport mode.
But I haven seen this surface in many years .

got it thx. my understanding was that there are times when vortex ring can potentially be initiated by a hover if the surrounding vortex becomes too turbulent and happens to be ingested by the props.

slup Posted at 2-2 08:33
Hi JJB,

Is this under the Fly app only ... you know this for a fact?

yes, its a fact   or my account is hacked by dji...

simple to check yourself

a) check map is empty
b) fly
c) check map is filled with 1 file
d) sync
e) check again  ;-)

cheers
JJB

davidms Posted at 2-2 09:43
got it thx. my understanding was that there are times when vortex ring can potentially be initiated by a hover if the surrounding vortex becomes too turbulent and happens to be ingested by the props.

That sounds more like propellor Drag, that causes turbulent air to flow over the prop tip reducing the effectiveness of the prop in creating lift.

Well you never know, and so far it’s just as probable as any other suggestions.

I think now with descent speed set at 3/4 metres max per second vortex is basically done away with , I hope ;+)::::

JJB* Posted at 2-2 09:51
yes, its a fact   or my account is hacked by dji...

simple to check yourself

But only Fly app... or do you see this for GO4 also ?

GavinThin Posted at 2-1 18:31
Hi DJI Stephen, Thanks for the reply and concern.

Yes, will do as suggested.

You are very much welcome GavinThin and thank you for these additional information. If you have any other inquiries or concerns with DJI. Please feel free to post it here at DJI Forum. We are here to help and support you. Thank you.

davidms Posted at 2-2 09:43
got it thx. my understanding was that there are times when vortex ring can potentially be initiated by a hover if the surrounding vortex becomes too turbulent and happens to be ingested by the props.

I thought of something earlier and wondered , barometers contained in the IMU , when we used to be building drones many moons ago, if barometers were not shielded correctly you would have a problem with drops and gains, I tested in low temperature -2/4 and this is exactly what was happening craft would gain 10/15 ft then it would drop suddenly, I thought it was because of cold but it may well be that barometers in the IMU are not shielded correctly.
Just a thought .

hallmark007 Posted at 2-2 11:03
I thought of something earlier and wondered , barometers contained in the IMU , when we used to be building drones many moons ago, if barometers were not shielded correctly you would have a problem with drops and gains, I tested in low temperature -2/4 and this is exactly what was happening craft would gain 10/15 ft then it would drop suddenly, I thought it was because of cold but it may well be that barometers in the IMU are not shielded correctly.
Just a thought .

interesting observation. It's also a mystery as to why it affects some, but not all, minis. I regularly fly in -5c to -10c and I have yet to experience an altitude drop/gain...knock on wood.

slup Posted at 2-2 10:41
But only Fly app... or do you see this for GO4 also ?

just sync my GO 4; DAT records still there....

JJB* Posted at 2-2 07:38
Hi Gavin,

Lot of users experience NotEnoughPower in their logs.

I have got constantly ESC error since I have updated firmware to .0400 and those errors disappeared after downgrading to firmware .0300. Then I have upgraded to .0400 using the DJI assistant 2 with all batterires and until now I only made indoor flights with prop guards but without any warning.

I strongly advise everyone that have ESC erros to do the same with all batterires.

GavinThin Posted at 2-2 07:49
Thanks a lot for the tips and tricks !
Will Definitely check it out.

One thing still to consider might be a battery firmware mismatch. You can check that by exiting the camera view before takeoff and go back to the home screen of the DJI Fly app. If the battery needs a firmware update, it will let you know only on that screen! A lot of people with combos updated only the currently inserted battery when performing the firmware update to .400 and did not realize the need to update also the other two batteries.

JJB* Posted at 2-2 07:56
yep, but did you know that the DAT files are removed when flights are synced in the FlyApp with the DJI china server?

So if you doubt your flight, first save that DAT file before syncing....  just a small tip from a "no knowledge person"

Thank's JJB yes I know that now thanks to you.

I have now disabled autosync in DJI Fly.

slup Posted at 2-2 08:19
Hi Gavin,

I'm late into this ... but have lately already seen several similar cases regarding uncommanded descents over at MavicPilots.com. Unfortunately nobody have been able to conclude what the reason is yet, we suspect some kind of fw fault in this stage.

How did you get the top picture of the flight log messages, FRAP or CsvView, how do I find it.

slup Posted at 2-2 08:19
Hi Gavin,

I'm late into this ... but have lately already seen several similar cases regarding uncommanded descents over at MavicPilots.com. Unfortunately nobody have been able to conclude what the reason is yet, we suspect some kind of fw fault in this stage.

How did you get the log capture in your post.

GavinThin Posted at 2-1 18:47
Hi m80116, Thanks for the reply and concern.

I have experience previously return my drones at power level of 12-15% .

ESC is Electronic Speed Control, a switching circuit designed to drive the motors.

You can update the firmware of the batteries in the AC itself if it is the first one. If you have more than one I suggest you do it (still inside the AC) through the DJI Assistant 2 For Mavic software. You need to connect your MM to a PC.

DJI Stephen Posted at 2-2 10:42
You are very much welcome GavinThin and thank you for these additional information. If you have any other inquiries or concerns with DJI. Please feel free to post it here at DJI Forum. We are here to help and support you. Thank you.

Thanks Stephen, I have submitted the data to DJI support team and hopefully they can analyze and found out what happen.
Will stay tune for it before my next flight attempt

fansd37fe0d3 Posted at 2-2 12:37
I have got constantly ESC error since I have updated firmware to .0400 and those errors disappeared after downgrading to firmware .0300. Then I have upgraded to .0400 using the DJI assistant 2 with all batterires and until now I only made indoor flights with prop guards but without any warning.

I strongly advise everyone that have ESC erros to do the same with all batterires.

Hi fansd37fe0d3,

Are the ESC error showing on the interface ?
I don't think I seen this before.
by upgrading all battery means I have to do it by inserting the battery one by one to the drones and update them while they are attached to the drones?
Or the multi-charging hub will do ?

Zelmani Posted at 2-2 14:28
One thing still to consider might be a battery firmware mismatch. You can check that by exiting the camera view before takeoff and go back to the home screen of the DJI Fly app. If the battery needs a firmware update, it will let you know only on that screen! A lot of people with combos updated only the currently inserted battery when performing the firmware update to .400 and did not realize the need to update also the other two batteries.

Oh, this is new to me..
Thanks !

so which means by changing battery, it's best to restart the interface (i assume it's a must since changing a battery means disconnecting the drone)
Then from there to see if the update firmware needed to be perform ?

Didn't know that battery contain firmware as well.
Sorry I am new to this and totally no idea on the hardware part.

slup Posted at 2-2 08:19
Hi Gavin,

I'm late into this ... but have lately already seen several similar cases regarding uncommanded descents over at MavicPilots.com. Unfortunately nobody have been able to conclude what the reason is yet, we suspect some kind of fw fault in this stage.

Hi Slup,

Thanks for the detailed explanation.
I have contacted the DJI support team and send them data accordingly.
Hopefully they manage to let me know what happen as well.

Tons of information you get here. i will try my best to understand them.

grahamjohnson10 Posted at 2-2 17:44
How did you get the top picture of the flight log messages, FRAP or CsvView, how do I find it.

It's data directly from the TXT log extracted by a Java routine developed by the same guy that made CsvView. It's executed directly from a command line interpreter.

GavinThin Posted at 2-2 20:49
Hi fansd37fe0d3,

Are the ESC error showing on the interface ?

Hello

Yes it shows but not always I see the warning. I usually see it on the Air Data notifications. If you want you can register, it is free, and then install the app on the same phone as DJI Fly app. After the flight I go to the Air Data app and upload the flight logs to the Air Data server. Then I go to the Air Data page and check my flights. Today, it's a sunny and warm day, I tested the MM outdoor for the first time since I refresshed the firmware of MM and batteries. No warning whatsoever. Tomorrow if I can I will do some flights in the park near the river.

On the other hand I almost lost my MM due to pilot error. I wanted to be seated, yes I am lazy, and all the benches were occupied so I went to a small amphitheater in front of a pond. The amphitheater is made of concrete slabs and when I turn the MM on over the slab and I got compass error. I calibrate the compass and did a hand launch without any problem. But when the MM was over the pond just a few meters from me I lost connection and the MM started a auto land. A novice pilot could panic and let the MM fall into the pond. I had to correct the position of the antennas and abort the auto land bringing the MM back to over the amphitheater.

When I say that you have to refresh the firmware with all the batterires, you have to do it one at a time, removing one after firmware update and installing the other. Do the same for all batteries that you have. You have to use the DJI Assistant 2 on the computer and link the MM to the computer through the USB port.

slup Posted at 2-2 23:36
It's data directly from the TXT log extracted by a Java routine developed by the same guy that made CsvView. It's executed directly from a command line interpreter.

"My advise is to report this to DJI & ask them to investigate the  event ... they have a much greater possibility to access more data as  they can read the encrypted DAT log stored in the Mini."

Really do not understand why DJI will not create a webpage that we can upload all flight log files from Drone or Smartdevice and get back full analysis.  It would be in best interests of DJI's customers and DJI.  Instead we have to rely on best efforts of people to decode information in flight logs and display information.  There clearly is more information available being we have seen glimpses of it when DJI has posted screensnaps.

HedgeTrimmer Posted at 2-3 07:53
"My advise is to report this to DJI & ask them to investigate the  event ... they have a much greater possibility to access more data as  they can read the encrypted DAT log stored in the Mini."

Really do not understand why DJI will not create a webpage that we can upload all flight log files from Drone or Smartdevice and get back full analysis.  It would be in best interests of DJI's customers and DJI.  Instead we have to rely on best efforts of people to decode information in flight logs and display information.  There clearly is more information available being we have seen glimpses of it when DJI has posted screensnaps.

Agree 100%

GavinThin Posted at 2-2 20:46
Thanks Stephen, I have submitted the data to DJI support team and hopefully they can analyze and found out what happen.
Will stay tune for it before my next flight attempt

It is my pleasure to assist you GavinThin and it is great to know that you have already submitted the flight data to DJI. Rest assured that our DJI support team will check and assess these data thoroughly for us to be able to know what really happened to the said drone. Again thank you for your understanding and please stay safe always.

GavinThin Posted at 2-1 18:56
Hi Tervist,

Yes I am flying my drone in Malaysia.

Yeah and i can confirm that unless the OP were stay near the beach and during the monsoon.. lol