DJI A2 / Tarot T15 Crash

[triise]

Hi,

Yesterday my T15 with A2 flight controller dropped to the ground.

Short version about the crash:
I was flying about 300 meters from HP at an height of aprx 100 meters. Suddently the multi did a flip and stabilized about a second later. Then i put it into HP on the IOC and pulled the stick towards me to get it home. It then flipped and the motors were pulling it towards the ground at an extreme speed. I didn't have the time to try to go to FS or anything, it just smashed into the ground.

Burned all ESC and motors as it was stuck i the snow on crash and it looked like the motors still wanted to spinn. One of the ESC was actually on fire(!) and all thats left of it is a black/burned piece of plastic / metal. It burned of all cables going in / out of the ESC. The frame was ok and all the props broken. I suppose my motors also is wrecked as they have a quite a bit of resistance as I try to turn them around - almost as if there is some grease in the engines. All motors were smoking hot after the crash and the waterdrops which came in contact with the motors were instantly varporating.

Hope to save the FC, frame and battery. It looks good now, but I have no idea how to check the FC. It looks unharmed at least. Suggestions?

I've tried to check the Datalog from the iOSD but I'm not sure how to interpret the data. Does anyone want to have a look?
The .dat file is found here: https://dl.dropboxusercontent.com/u/31661823/Privat/FLY053.DAT

Curious about what caused this.

Sad way to end this years easter.... I think I'll be finding a new hobby :upset:
View attachment 17716View attachment 17717View attachment 17718View attachment 17719

Data on my multi:
Foxtech 4016 380kv motors
Hobbywing 40A opto ESC
DJI A2 FC / iOSD Mk2
Foxtech 1555 mkII props
Tarot T15 frame
RC-timer gimbal with Alexmos controller for FLIR PathfindIR + daycam.
Foxtech 10.000 mah battery
Futaba T8FG TX
DJI AVL58 video tx/rx

 

[soler]

I know the wiring on the tarot can be a bit of a pain, was there any chance that there was a short or bad connection inside the frame for such disastrous results?

Have you tried looking at your onboard OSD to see if that shows a problem?

 

[triise]

Actually the first thing that happened was that the OSD stopped showing data on my video link. I then powercycled the Tarot and it came up good again. Then after some minutes it stopped again, and then only seconds after this happened. (Loosing the OSD has been a problem for some time, and I doubt its related directly). The OSD has logged the whole trip and I've posted the datafile in my first post for those who may want to have a look at it.

Now I've partly disassembled the Tarot and as far as I can see there is no short. My cabling was done through the arms and into a selfmade power distribution system (all wires soldered to 4mm copper rods).

I know the wiring on the tarot can be a bit of a pain, was there any chance that there was a short or bad connection inside the frame for such disastrous results?

Have you tried looking at your onboard OSD to see if that shows a problem?

 

[econfly]

Interesting. A short would explain everything, but I can't see what other explanation would result in the burned out motors and ESC fire. Could the short have been in the ESC that burned? If it shorted on the supply side then that would short the entire system. How did the battery look? Was it puffed up or evidently damaged?

Edit: changed my mind, see below.

 

[econfly]

Here is the sequence I see in the data file. You are flying in GPS/Atti and elevator is at full for a period of time (other inputs roughly centered), then there is a quick pitch, elevator drops to neutral and the flight goes out of control. At that same moment, control switches from GPS/Atti to manual mode. A crash shortly follows.

The main voltage plummeted right before the crash, but after the brief period of out-of-control manual mode flight. After the crash the voltage came back up and some of the motors were running for a while (motor 8 in particular was cranking hard for quite a while). I think that explains the burned out ESC.

Any chance you bumped the mode switch into manual while flying forward at full stick? That would explain things, the quick pitch downward, a couple of flips, then the crash.

 

[Glennyboy]

Hi,

Yesterday my T15 with A2 flight controller dropped to the ground.

Short version about the crash:
I was flying about 300 meters from HP at an height of aprx 100 meters. Suddently the multi did a flip and stabilized about a second later. Then i put it into HP on the IOC and pulled the stick towards me to get it home. It then flipped and the motors were pulling it towards the ground at an extreme speed. I didn't have the time to try to go to FS or anything, it just smashed into the ground.

Burned all ESC and motors as it was stuck i the snow on crash and it looked like the motors still wanted to spinn. One of the ESC was actually on fire(!) and all thats left of it is a black/burned piece of plastic / metal. It burned of all cables going in / out of the ESC. The frame was ok and all the props broken. I suppose my motors also is wrecked as they have a quite a bit of resistance as I try to turn them around - almost as if there is some grease in the engines. All motors were smoking hot after the crash and the waterdrops which came in contact with the motors were instantly varporating.

Hope to save the FC, frame and battery. It looks good now, but I have no idea how to check the FC. It looks unharmed at least. Suggestions?

I've tried to check the Datalog from the iOSD but I'm not sure how to interpret the data. Does anyone want to have a look?
The .dat file is found here: https://dl.dropboxusercontent.com/u/31661823/Privat/FLY053.DAT

Curious about what caused this.

presuming the horizontal line is time in seconds then this is how I read it....

up to around 50 seconds you are flying in gps mode.....at this point your sats go to zero, so the ship would go automatically to atti mode, at this point its showing you flipped into manual mode for roughly 2 secs (this would explain the first flip) because then you shift into GPS mode but it isnt gps because you have no sats so its actually atti mode, depending on your flying experience this can be frightning because it just drifts.....later at around 220 it shows shifting modes again...gps...atti and once again manual....this probably caused the second flip. the main/can/bec voltages remain stable throughout the flight so im guessing no shorts, but for some reason your sats went from 16 to 14 to 1 and then zero. this has been happening to my craft for the last 2 months incidently.

Im not saying it was your fault its just how i read the data.

I feel for you mate it must be horrible

 

[soler]

Did you update to the latest GPS firmware, i see there is version 20 for one part of the GPS, I forget what. This is related to the Sat count dropping.

 

[triise]

Hi Glenn & Econfly,

Thanks for your input. I'm pretty sure I didn't switch to manual mode, but I cant be sure. I have my IOC switch and Mode switch side by side and maybe, just maybe I may have accidentally flipped the switch (But if the log says I did, I probably did...). But heres the thing: From the first flip until crash it went about 5-10 seconds. The latter switches btw gps/atti/manual is actually me flipping the switch while searching for the Tarot (220 sec). If I lost the GPS (which is new info for me), I'm starting to think that it could have something with my iOSD to do. It has been acting a bit strange lately and cutting the overlay on my video stream. Its connected directly to the CAN-hub on the GPS. Maybe it did something to my GPS (maybe the iOSD is faulty...)

@Soler: I'll do a check on firmware updates tomorrow, but I'm pretty sure it's up to date.

This could be my own fault for all I know, but It's always good to have a little investigation done after loosing a lot of money... But, life goes on and hopefully I'll have better spirits when I figure out what went wrong

Now I'm off to bed having bad dreams about the A2-controller....

presuming the horizontal line is time in seconds then this is how I read it....

up to around 50 seconds you are flying in gps mode.....at this point your sats go to zero, so the ship would go automatically to atti mode, at this point its showing you flipped into manual mode for roughly 2 secs (this would explain the first flip) because then you shift into GPS mode but it isnt gps because you have no sats so its actually atti mode, depending on your flying experience this can be frightning because it just drifts.....later at around 220 it shows shifting modes again...gps...atti and once again manual....this probably caused the second flip. the main/can/bec voltages remain stable throughout the flight so im guessing no shorts, but for some reason your sats went from 16 to 14 to 1 and then zero. this has been happening to my craft for the last 2 months incidently.

Im not saying it was your fault its just how i read the data.

I feel for you mate it must be horrible

 

[econfly]

It looks to me like the sats drop after the crash, not before. I see full elevator for a period of time, then it pulls back to mid-stick, mode switches to manual, aileron input flips it, then it pitches down and crashes. After the crash (or right at it) the sats plummet to 0.

Anyway, sorry about the crash. Been there.

 

[triise]

Gentlemen!

After some research and investigation it looks like it's pilot error after all...
I've now sold the T15 frame, A2 and FLIR (which survived) and will be going into the Phantom business as the risk / cost is to high for me on these expensive crafts. Maybe I'll pick it up sometime later.
Thanks for your help and tips!

Regards,
Tore Riise
Norway

BTW, pano pic taken from the T15 before the crash "last positive memory" is important to remember...
View attachment 17843