Immediate crash after arming fresh quadcopter

Hi there,
My friend built a drone by using Pixhawk 1 unit.
Before actual launch with no props we checked mostly everything and seems OK. Also we did a throttle control with RC and that was working fine. However, later with props when we wanted just to hover in stab mode for a first time, after arm switch turned on it immediately(well after short pause obviously which is typical for AP) screamed with motors and hit a sealing :smiley:.
While reviewing logs, I see that for some reason RC input channel 3 stays at 1500, while this is obviously incorrect, because Thr was at min on Radio.
To me this crash looks completely strange from the logs prospective.
00000028.BIN (545.6 KB)

Could you please shed some light what was actual reason for the crash?
On a channel 6 arm switch
On a channel 7 motor stop switch

On the first hop, the emergency stop shut off the motors. It was disarmed after.

On the second hop, the emergency stop and the disarm are triggered at pretty much the same moment. Both have the same effect.

Maybe so, but the FC is seeing 1500 on the throttle channel so it wants to go. Your motors all spin up to almost full power right away, probably because the FC is seeing that 1500 on RC3. Of note, I don’t see any movement of any of the controls RC1-4 (AETR) in the log. However RC6 and 7 function. Might be worth looking at the radio setup.

Also the the arming checks are disabled . You may wish to consider setting ARMING_CHECK to 1 (recommended). I don’t know if it would have picked up on the problem with RC1-4, but it may save you other problems down the road.

First of all, thank you for the feedback. :smiley:

Then, to explain, the first two armings was with no props attached (actually loosely set, not tightened). And that checked if arm/disarm working well (CH6) and if an emergency motor stop is working as well(CH7). And then 3rd start was with props. The goal was to just slightly hover above the ground that is why you see no CH1-4 changes at all because there was none :smiley: So the only 2 switches were engaged over all of the time.
But thanks for confirming my suspicions.