OpenTx and Safe Select


Wake up! Time to fly!
What is the switch range you are using? Since safe is looking for on or off normal position should be at 1000us and on should be 2000us. If you put it on a three way then using the middle position only goes to 1500us and wont trigger the safe feature.

If you are on a momentary check and make sure it toggles between 1000Us and 2000us same for a normal 2 way switch. If you only have a 3 way available then you have to make sure the middle position is set to 2000us


New member
I am also not able to assign a switch to SAFE Select on my Radiomaster TX16S. If I do the routine of moving the sticks to the inside (or outside depending on how they are configured) corner and flipping a switch 5 times, the plane will switch from SAFE to AS3X and back if I do it again. But the switch won't work to do that. Only this initialization routine does it. In other words, I can't do it while flying, which is the whole point. I feel like I made a little bit of progress, but not enough to be useful. It would really help if someone knew how to do this so I don't have to go out and buy a whole new radio.

I have the exact same issue.
Safe binding works but i cant switch it on and off.
Has nobody found a fix for this yet ? :(


Look at the bones!
I have the exact same issue.
Safe binding works but i cant switch it on and off.
Has nobody found a fix for this yet ? :(

I had posted my solution a couple of months back, but the mods killed it because my user name was unpopular (Nyah!).

I solved this by assigning a knob to the output and watching the output counts. What I discovered is that if I set the output too high or too low, the receiver would not recognize Safe Select. My Carbon Cub, T28 and Night Radian all exhibit the same behavior. The Cub knows from 32 position Safe, Intermediate and AFS3X, while the T28 and Night Radian (both BNF basic with Safe Select) only know from Safe Select and AFS3X mode.

At 1019us, my Cub goes into AFS3X, 1500 for Intermediate and 1981us for Safe Mode On.
At 1142us, my Radian goes into AFS3X at 1858us for Safe Select.

Hope this helps (and sticks).


New member
You are right. I also discovered this yesterday when I read about spektrum transmitters and saw that spektrum doesnt use the same output range as opentx transmitters.

I simply limited my channel outputs to 85% and then it worked.
This also removed the top and bottom deadzones of TAER controls.

The only channel that needs 100% output for spektrum receivers is the throttle -100. If you put that one on -85% it wont arm the esc.

I hope this helps other people who have this issue :)


Site Moderator
Staff member
... If I assign channel 5 to a switch it does.. nothing....
Somewhere in your Tx there is a menu screen than shows the reaction to the stick movement of each channel. Usually a bunch of bars that move as you move the sticks.

Is channel 5 responding? If not you have not setup the Tx correctly.