Union Thug writes:

I am gonna break a cardinal rule here and respond to one of your
posts.I am doing this because you have raised a question others might
be interested in. I cannot speak for other jets ( I am sure they are
similar) , but the Boeing uses an ADIRU which has 2 sets of three
laser ring gyros either set will sufice to measure acceleration, pitch
and roll. And there is an ADIRU for each side of the cockpit (Capt &
FO). The IRS will also provide attitude info and there are two of
those also. Keep in mind you can switch the display to all on system
one or two. With this level of redundancy we dont even practice
partial panel or raw data stuff in the sim, it is simply not
necessary. Years ago I flew an approach with just backup instruments
in a turbo prop after a total EFIS failure and it was no big deal. I
think you might be making more of this than you need to.

I was talking about small aircraft with the kiddy glass cockpits, like the
G1000. I realize that large airliners have a great deal of redundancy built
in. They also have more ergonomic instruments and less of a tendency to
bundle everything into a single package.