mr. Chief Pilot is talking through his hat.

Cat I is usually 200ft when based on altitude.

Cat IIs are usually 100ft DH and Cat IIIA is a 50DH while the Cat IIIB is a AH.. decision height versus alert height. On a IIIa, you make a decision to land or go around at 50ft. With an AH on IIIB, you just continue and need to see NOTHING to land.

There is no one, to my knowledge, certified to IIIC which is zero/zero. And that is not due to aircraft systems but were there a crash there is no way to get the accident response team to the runway and no way to determine if there was a crash rather than a successful landing.

Note too that ATC will clear you for the ILS, not for a Cat I or Cat IIIB approach. they will call RVR but they do not know your mins and for example, if you are Part 91 in the US, you don't have mins per se. You can shoot a 'look see' if reports are below mins, something the -121 and -135 ops can't.

And Cat IIIs are to an obviously lower altitude than Cat IIs.

 

Well, he wasn't speaking as an authority on the Cat II and III's. Neither one of us are very familiar with the details of each (and I didn't bother looking them up). He was just saying, what he believed to be the case, and wasn't sure. I did know that Cat II was a little lower and Cat III was a little lower than that. Once again, I think we've answered the question and thanks to everybody for thier input.

papa t

 

When I go missed, my eyes go right back on the gauges. If the runway environment is in sight after I execute the missed, I wouldn't even see it. All efforts are put to getting the airplane climbing again. Landing is no longer an option once the decision to go missed is made.

 

Ive heard from many instructors here at my part 141 school that what has been said so far is consistent. MDAs are set in stone. Under no circumstances should the aircraft be below that altitude unless going for a landing. This is generally because you are leveled off at that altitude as you make you way to the MAP so there is no inertia to carry you down.
However, for ILS you make you decision at 200 feet. Now with small GA aircraft, generally you will pop right up and even 20 feet is not much of a loss. Now one instructor pointed out much larger aircraft. Suppose a 747 was doing an ILS approach at an airport that only had Cat 1 ILS. He shoots the approach down to 200 feet, no field in sight and he puts the thrust levels at full... there is going to be some spin up time plus general physics of stopping that honking thing from going lower... it could go quite a distance below the DA!

 

Actually in the landing configuration, you are above the critical RPM/% where you get almost instant response from the jet engines. Time from idle can be lengthy but normally on final, gear down, flaps in landing position, the power is such that small movements get quick response. And when you go to go-around thrurst, it happens quite quick.

But yes, in Cat III approaches with a 50ft DH/AH, it is possible to touch down during the go-around so it is imperative the VSI be pointing UP and not down when you suck up the gear. Metal on concrete is an ugly sound...

 

Heh heh... great advice for anyone - not just 747 pilots on Cat III approaches :-P