Originally Posted by Sputnik

In no particular order:

-It keeps getting screwed up (being used on inappropriate approaches--essentially anything with a non straight segment). To be fair it IS confusing--we were taught that IAN works for everything but RNAV RNP and that's how NOI guides were written. Not so true nowadays

-There are more and more non-compatible approaches being built so only more room for confusion

-Finally getting LPV. Just like GA

It is not official or final, IAN is still on planes and perfectly acceptable to use. It is still taught/tested in all qualification syllabi.

I find myself the slightest bit irritated we were taught for years that IAN was utterly superior in all ways to LNAV/VNAV. And now suddenly "never mind.". No one cares what I think and my paycheck still clears so I'll get over it

On the subject of AIII vs autoland. AIII allows the aircraft to do Cat 2/3 with less than two functional autopilots, and/or with one engine inop. Not something that comes up much. We did have a lot of planes with expired autoland during Covid and I heard of guys having to do AIII then. Given a choice, I think most people will pick autoland over AIII.

At a small number of airports AIII allows takeoff at 300 RVR.

As others have mentioned, at 8 US airports it will (assuming we ever get final FAA approval) allow Cat 3 down to 400/400/300. Which is entirely about Seattle and the 50ish mornings a year Alaska is landing while we divert. It is being trained now as part of CQ. Just to be clear, this reduced Cat 3 minima requires an autoland AND AIII. AIII alone still only gets you down to 600 RVR.