GPS assist

[piersherbert]

I have a question about GPS assist. This mode will happen automatically if the pitot pressure fails, but can you select it manually if you suspect the pitot pressure may be erroneous (e.g. iced pitot tube)

 

[dynonsupport]

It's not manually selectable. In reality, if you have any non-zero airspeed value at all, you'll get an attitude that does't "diverge" (in other words, it may be somewhat incorrect, but it won't run away or spiral you in). In short, the system's rules on GPS assist ensure that when you have GPS input, the attitude will switch to GPS assist mode when appropriate.