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Mini 2 crashed but why??

Hi All

I was attempting to do a roof inspection. A very constricted site with about 30 ft between two 8 storey buildings. I got up to about level 6 when the drone went crazy, crashed into a wall and fell to the ground. I couldn’t see what happened as it was directly above me , with the sun behind.

Could be either loss of GPS signal, RC disconnected, updraft/wind turbulence, Interference from cell towers on the roof.

I have tried to upload the file to AirData website but it only accepts 15 MB (the file is .5 GB).

Any ideas wold be appreciated.

I have attached the flight log file , if it makes any sense to you.
Glen ... what's happened to you?
If you post your flight data, someone will be able to give you the help you asked for.
But without the data to show what actually happened, only guessing is possible.
 
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I have some files on the card but no txt file. I can only assume that the card was not inserted correctly. Thanks for your help. I really appreciate it. I have learned a lot from the thread but this incident will remain a mystery, Until next time...
 
I have some files on the card but no txt file. I can only assume that the card was not inserted correctly. Thanks for your help. I really appreciate it. I have learned a lot from the thread but this incident will remain a mystery, Until next time...
The relevant file is not on an SD card.
It is in your controller if you use one with an integrated screen, or in the phone or tablet if you used that for the flight.
See post #4 for details and ask you need any extra help to find it.
 
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@Meta4 I have uploaded the flight record and a link to the Flight Log Viewer record. It looks interesting but not sure what it all means...

Will now try to view the flight data on AirData. Let's see what it tells me...
 
Ok

In the narrow space between two high buildings, only a small part of the sky was visible to the drone's GPS receiver.
The few sats that were visible in that small part of the sky and didn't have sufficient spread to give good location data.
As a result we have no reliable speed or distance data.

The drone never had any GPS data during the flight.
Below 13 metres, the drone was able to use the downward facing sensors (VPS) to provide horizontal position holding.
But once the drone went higher than 13 metres (at 1:38.5), it had no position holding ability and any breeze was able to drag it away.

The only joystick inputs you made were to ascend and descend, but the drone drifted on the breeze and hit one of the buildings 21 metres up at 1:52.7

The layout of your site is unknown.
But if possible, it would have been a good idea to launch from out in the open away from the buildings, where the drone would have had full GPS.

There was nothing wrong with the drone.
It was the flight environment that was the problem.

And for the benefit of one particular member, interference had nothing to do with the incident.
 
...It was the flight environment that was the problem.
Just adding in some thing's for your sake @Glenh & all others on this forum that will read this thread now & in the future...

The main culprit causing this incident wasn't as said, your drone... & the environment merely made the incident possible. Even though it may sound harsh, the main cause was ignorance & that you didn't pay attention to info you got or didn't get from your screen.

Looking into the log you shared, clearly show that your screen device wasn't properly attached to your RC during the first half of the flight... nothing is recorded until approx. 56sec into the flight... so you didn't try to confirm anything there in order to secure your upcoming flight.

When the log starts to record we can read off that no HP have been recorded yet... which isn't strange as the Sat. count was low & the GPS level was only 2 (how much the flight controller trust the positional data... 5= best & HP is recorded when it reaches 4).

When the incident occurs the GPS level have just dropped further to 1 then shortly after to 0 ... & then the flight controller fall back to ATTI mode which still is possible to handle but you've lost all positional hold support, no auto braking when releasing the sticks & the drone freely drifts with whatever affecting it... so if not used to maneuvering in ATTI, not prepared for the switch & having the drone really close to obstacles... a disaster is very likely & not far away.

Below I've depicted the flight log in a chart including flight time, flight mode, Sat count, GPS level & calculated heading speed.

White background up to the 56sec mark = your screen device was most probably disconnected from your RC (or the app wasn't started)

Brown background = Ordinary GPS mode or Normal mode

Green background = ATTI mode

Green graph = Sat. count

Blue graph = GPS level

Purple graph = Calculated heading speed

The crash happens pretty much right after the GPS level have dropped from 2 down to 0... there we also see a rapid increased heading speed. (have placed the chart marker just there at 112sec... read off the graph values for that point in the chart legend in the bottom)

(Click on the chart to make it larger)
1697634098673.png
 
To bad you didn't wait for homepoint update. As said, flying without gps, atti mode, takes some practice..in open spaces. Hope you're flying again soon.
 
To bad you didn't wait for homepoint update. As said, flying without gps, atti mode, takes some practice..in open spaces. Hope you're flying again soon.
Waiting wasn't ever going to get a homepoint.
The site blocked too much of the sky for proper GPS reception.
 
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Waiting wasn't ever going to get a homepoint.
The site blocked too much of the sky for proper GPS reception.
So true, but he would have eventually figured out it wasn't good to takeoff. Lesson learned (hard way) hopefully others too.
 
So true, but he would have eventually figured out it wasn't good to takeoff. Lesson learned (hard way) hopefully others too.
Not necessarily.
He took the drone up to 70 feet, quite likely hoping that he would get GPS up there, but it didn't work out that way.
Launching without GPS and flying to where you get GPS is a legitimate thing to do in some situations.
But flying in atti mode, close to obstacles without proper care and control of the drone is a good way to crash your drone.
 
Hi All

I was attempting to do a roof inspection. A very constricted site with about 30 ft between two 8 storey buildings. I got up to about level 6 when the drone went crazy, crashed into a wall and fell to the ground. I couldn’t see what happened as it was directly above me , with the sun behind.

Could be either loss of GPS signal, RC disconnected, updraft/wind turbulence, Interference from cell towers on the roof.

I have tried to upload the file to AirData website but it only accepts 15 MB (the file is .5 GB).

Any ideas wold be appreciated.

I have attached the flight log file , if it makes any sense to you.
Is the drone repairable?
 
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Is the drone repairable?
Some missing prop blades, at least one broken arm, cracked and warped hull. I have sent it to the DJI workshop in Melbourne for a repair quote. Apparently they also offer a refurbished replacement at a cost. See what happens
 

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So this is the story.
I accepted a job without awareness of the site and conditions. When I got there I realized that i) the take off and ascent would be somewhat constricted ii) there was a steady but ok breeze but some concern about turbulence between and above the buildings iii) I would be likely to lose direct line of sight when above the building iv) I had noticed some Magpies (the winged variety) in some trees nearby so there was a possibility that the drone would be buzzed on reaching clear sky v) some cell transmitters on the roof but hoped that would be ok as long as I was not too close,.. vi) Sunset was approaching so I would need to get required results soon.

I was keen to do the job as the client is a Civil Engineer so a possible pipeline of work in the offer.

I took off in haste, without my usual due diligence. I noticed that I was low on satellite coverage but hoped/assumed that there would be more when I reached clear sky.

I think that the reason that the "RC was not connected"was that I was fiddling with the settings (max height/rth height) while ascending. Maybe??

The rest is history as per @Meta4 Flight Record analysis and all of your comments. Thank you for that. I appreciate your time, knowledge, and sharing of your experience.

Lessons learned:
Trust in your situational awareness and understanding of conditions.
Always conduct due diligence on/before take off.
Don't allow your client to be your project manager.
Pay careful attention to the information on your screen.
Upgrade to a Drone with good obstacle avoidance features.
Practice flying in atti mode.

What else?
Thanks again for your input
 
Upgrade to a Drone with good obstacle avoidance features.
Obstacle avoidance wouldn't help in this case as OA requires full GPS for the drone to be able to react correctly.
 
Some missing prop blades, at least one broken arm, cracked and warped hull. I have sent it to the DJI workshop in Melbourne for a repair quote. Apparently they also offer a refurbished replacement at a cost. See what happens
Just sent my banged up little Mini 2 into the DJI Melbourne service centre last week mate and less than 5 days later I got back an 'as new' refurbished Mini 2. They generally don't bother with repairs and instead send out a refurb. Mine was a good couple of years out of warranty that I sent in but they still only charged me $89 for the 'new' unit. Was very happy with the outcome and the overall service from DJI was brilliant. They were very efficient.
 
Some missing prop blades, at least one broken arm, cracked and warped hull. I have sent it to the DJI workshop in Melbourne for a repair quote. Apparently they also offer a refurbished replacement at a cost. See what happens
Not suprising damage. The camera/gimbal doesn't look too bad from what I can see. That's the most expensive thing. Good luck!
 
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