can I put safe and as3x on the same 3 position switch?
In the Receiver, Flight Modes are really Stabilization Modes. They are controlled by the input from 1-2 channels. Typically there are 3 different setups.
1. SAFE On/Off, AS3X always on (this is the standard SAFE Select setup)
2. AS3X with multiple modes (ie off, mild & wild) (This is the standard AS3X-only setup for most home programmed setups)
3. AS3X/SAFE in 3 variations (typically AS3X off, AS3X on, SAFE on for home-programmed stuff, AS3X only, SAFE Intermediate and SAFE Beginner for SAFE factory setups), plus a ‘Panic’ mode triggered by a second channel.
Flight Modes on the radio allow you to syncronize a lot of settings by having those settings (mixes, rates, expo, et al) all tied to the flight mode and the flight mode controlled by 1-3 switches (depending on radio and model type you can have up to 10 flight modes in the radio), this is necessary for advanced programming.
With Forward Programming the Radio Flight Modes and the Receiver Flight modes can be sync’d to some extent. But that only works for a receiver you have programmed yourself via Forward Programming (an unlocked 637TA supports this, the 636B does not)