**** big crash due to control failure ****

[Cloudbuster]

Hi all , well finally crashed my 680 tarot tonight, not to miffed though as it seems it was not pilot error but probably a controller failure of some sort !!! Flight was all good with about 5 mins done on a simple altitude hold flight just stoofing around. The problem started as soon as i switched out of altitude hold when the hex bucked one way then accelerated to the left and power dived straight at the ground probably hitting at an angle of about 25degrees and probably about 40mph, amazingly the only damage was a broken motor shaft one wrecked motor and two trashed props !!! All in all a lucky escape finacially !!! I am convinced it is a control glitch of some kind as a powered dive is just not possible under normal flying parameters as the hex will spend all its life trying to stabalize itself. Any others out there that have had similar please share your expierience.

P.S apm 2.5 controller using ver 3.0

Regards rob

[optiplex]

are u sure that when u switched out of alt hold mode it didnt switch to auto mode maybe or other mode ?
it happens to me some times, im in rtl and than go back to stab but forget the other switch on my tx cause its 2 switches combo so it goes into auto mode and looks like its out of control .... just a thought

[dazza22]

have you had your multi flying well in the past  i.e Auto,RTL loiter  ?

only ask  because as you probably know in 3.0 you have to have the compass and barometer set up well.

[rickp]

Or maybe, you know, post the log so we can see what happened...

[robshaw]

I find that if the pwm values on your tx mixes and flight modes aren';t clearly defined it has a tendancy to dwell around a mode. For example if loiter is mode 1, auto mode 2 and alt hold mode 3. If you switch from alt hold to loiter and your rx is slow switching from the mode 3 pwm to  mode 1 pwm it will go into mode 2 briefly on its way through.

[rickp]

I find that if the pwm values on your tx mixes and flight modes aren';t clearly defined it has a tendancy to dwell around a mode. For example if loiter is mode 1, auto mode 2 and alt hold mode 3. If you switch from alt hold to loiter and your rx is slow switching from the mode 3 pwm to  mode 1 pwm it will go into mode 2 briefly on its way through.

Right - something that we could tell from logs. Or we could keep randomly guessing...
Frustrating....

[Cloudbuster]

Right - something that we could tell from logs. Or we could keep randomly guessing...
Frustrating....

I have downloaded all logs from the ardupilot but seem to be getting a number of different error messages when trying to display the graph info !!! I am still very new at this and not sure what to look for in the log but i am guessing any spurious reading that is prevelent is a good place to start, being a bit thick i removed the ardupilot and installed it on a 650 quad that was built waiting for a new controller as the KK.2.0 that was on it was useless !!! I have done several motor tests with the new install so i have yet to find the correct log file for the fatal flight... I guess its possible to just upload the log file here when i work out which one it is ....

I have studied the film from the gopro and its obvious that the motors go to full throttle the dive in reverse straight down until impact !!!

Regards rob

[rickp]

If you';ve not used the APM in anything else, we want the last .log file. You can download these using the CLI or Mission Planner.