Hello all,
We were flight testing last Friday and had a fatal crash. The setup is as follows.
Flight Controller: Pixhawk 2.1
Firmware version: 1.7.3
TX: RadioLink AT9
RX: Radiolink R9DS
Telem: RFD900+
https://logs.px4.io/plot_app?log=4e4e4e3c-d62e-4d72-9cba-939ecddf405a
We have a companion computer where we change to offboard mode to send position setpoints, but not during the mission. I suppose that something triggered OFFBOARD
mode, and since the COM_OBL_RC_ACT
was set to 0 which is POSCTL
, the copter switches to POSCTL
for a split second and then drops to STAB
. Since the throttle was set to 0 from the TX, copter crashed with 0 thrust in about 1 seconds since it was about 10 meters above ground. While it was dropping, it switches to POSCTL
and back to STAB
again.
- Might this offboard attempt be related to some noise on TX or RX side? The
RC_MAP_OFFB_SW
was set to 9 so we also have an offboard switch on the transmitter. But never touched it really. - The TX flap was in the default position which is
STAB
when the offboard reject happens, but since theCOM_OBL_RC_ACT
is set toPOSCTL
, shouldn’t it stay that way? It seems that the RC tx somehow overrides all the commands(twice). This could be a critical bug which might need handling.