Dangerous situation: fastboot during flight

We had an issue today where our HereLink “changed” to fast boot during the flight and the SBUS output did freeze in a non neutral position. There was no possibility to make any input until a full reboot was performed (by pressing the power button for 30 - 60? seconds).

I’m still waiting for the log files to arrive but wanted to draw attention on the issue anyhow.

We had same problem a while ago and i asked if it was possible to configure how failsafe on airunit reacts on failsafe and as far as i understand it holds last position, very dangerous in my opinion.
We solved it by having a piece of custom electronics in between airunit and pixhawk, if the sbus comes from the airunit it let it pass without interfering, as soon as the air unit goes into failsafe it takes over and puts the channel were we configured them to be in that case. My copter now if i switch off the herelink goes into rtl and all channel are brought to 1500.
I already brought up the issue some days ago but they didn’t show much interest nor understand how dangerous it could be.

Thank you, but I don’t think the air unit has a problem. I tested to switch of the remote unit today and RTL was triggered instantly.

It seems to be that the remote unit can hang up and keep sending the last pwm values from the sticks before it did freeze.

One would need a fail safe mechanism to check if the pwm values do not change form some seconds to fix that.

It is not a problem it is how it is designed. If the ground unit switches off, the airunit holds last good position. Even if a failsafe RTL is triggered the ail, elev, yaw positions could be way off center and trigger some very weird behaviour.
During RTL elev and ail are ignored but yaw is not, so the copter would keep on rotating while coming home and once it would switch from RTL to LAND than the elev and ail would kick in (ail and elev work during LAND) and make a strange situation even worse.
Hope you fully understand what it means to have radio holding last position…

Ok, that sounds weird. I will test that tomorrow. Thank you for the hint!

@HighFreq71 is there any documentation on this? I could not find it in the docs?