Failsafe question with Preset Swich

My failsafe is setup and goes into failsafe mode fine, throttle down

When I put my turn off my Tx my failsafe is setup and goes below Pwm just fine

My question is my switches also go back to a preset position throwing my Flight Mode into STABILIZE (or whatever I have it set to), so is there a risk of it just dropping out of the sky since it switched to STABILIZE and the throttle is below zero and my Flight Mode changed from Auto to Stabilize with throttle down all at once?  Or is the Fail Safe settings going to override the STABILIZE Flight Mode change and preset switch setting?

I assume I'll be okay but I just want to ask before I try it ;)

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  • Developer

    Edgar,

         This is a very good question.  The short answer is it should be ok.

         The longer answer is the throttle is not passed through from the moment it drops below the FS_THR_VALUE (defaults to 975) so even if the flight mode change got through first, when it switches to failsafe, the throttle should still be high.  So it would be more like you're in stabilize with non-zero throttle so it should still RTL.

         There's some additional complexity in that both the flight mode and failsafe have "debouncing" time.  So this is the time between when the switch or throttle changes position and when we actually register the change.  So for the flight mode switch it needs to be in it's new position for 0.1seconds.  For the failsafe to kick in the throttle must be low for 0.06 seconds (3/50th of a second)...so the failsafe should always trigger before the flight mode change anyway.

         There are some changes going into AC3.1 that ensure we handle this in an iron clad way - it will ignore changes to all switches from the moment the throttle low.

         If you want to be totally sure there's never a problem you could set the receiver up so that it moves the flight mode channel to a flight mode that you never set-up as stabilize (like RTL or LOITER).

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