Descent below MDA -- what would you do?

Peter wrote:

Doug Carter wrote

Might, except the glideslope is not guarenteed below something like
100'.

The localiser should be, otherwise CAT 2/3 approaches wouldn't work.
The coupled autopilot uses a radalt for the last ~ 100ft but it uses
the localiser all the way down, AFAIK.

In an emergency and with no other options, technically speaking, one
should be able to fly an ILS all the way down, in 0/0 conditions, and
walk away from it.

On an ILS, at TDZE + 100, you are 2000 feet out from the GS antenna, or
1000 out from the threshold. You would have to make some drastic pitch
changes (i.e. double your descent rate) to land short of the threshold from
that point. If you made it to DH with the needles centered, just hold that
pitch attitude and power setting another 10 seconds or so, and you're there.

That being said, it's not something you want to do unless you've run out of
other choices. I've done it once -- when I was an instrument student. My
instructor took me out on an evening when the ground fog was already
starting to settle in when we took off. By the time we came back a couple
of hours later, things were pretty well socked in. Our home field (CDW)
had a localizer only; we took one (rather pointless) shot at that, then
went to the next field over (MMU) which had an ILS. That too was below
minimums, but we landed anyway. Fortunately, the same conditions that lead
to ground fog also make for an easy ILS -- zero wind. I kept the needles
in the donut all the way down and just kept going when we got to the DH.
Eventually, the runway loomed out of the soup and we landed. It was so
thick, we could only see a couple of runway edge lights ahead. The tower
never saw us. Good for war stories, but not an experience I'd like to
repeat.

Of course, we were infected with a bad case of get-home-itis, or at least
my instructor was and I was foolish enough to go along with it. He had to
be to work the next day, and landing 10 miles away from home was close
enough. We had fuel to make it to someplace with better weather but much
less convenient.

Given a choice of where to bust minimums, I'd go for someplace that has a
published Cat-II/III approach. Even if you're not certified for it, you
know the nav signals are good down to the ground, and those runways tend to
have gazillion-megawatt approach light systems. Might as well give
yourself every advantage you can get.