Approach speeds for ILS

"Richard Kaplan" wrote in message ws.com...
"Snowbird" wrote in message
om...
the last 3rd of a 6,500 ft runway. Dunno what the tailwind was --
nothing too startling (10-12 kts?)

That is a very significant tailwind for landing; it would not surprise me if
a 10 knot tailwind doubled your landing roll vs. a 10 knot headwind or if
the total landing distance increased between 50% and 100%.

Hi Richard,

As far as I could tell, it didn't do a thing to my landing roll.
What it affected, drastically, was the distance it took my plane
to slow to landing speed and consent to stop flying.

I'm very glad I had a CFI who had me try this. Experience is
worth 1000 words. After doing so, I can easily see how an overrun
accident (or loss of control if someone tried to force the plane to
land) could occur on a long, ILS-served runway.

One size definately does not fit all situations for ILS procedures.
I don't think it's a great idea to fly ILS routinely at 60 kts --
as someone pointed out, the margin over stall is much lower and
the configuration changes needed for correction much larger than
at 90 kts. OTOH, a practice of never retarding the throttle
until over the threshold (as I believe Rick Durden suggested)
would IMHO definately be a bad idea on a shorter runway (say
5000-6000 ft) w/ a tailwind.

And my advice to instrument students is: make sure you actually
land out of a good number of ILS in a number of different
circumstances,
preferably ILS in IMC or at night. For that matter, make sure you
land out of a variety of approaches.

Cheers,
Sydney

(Snowbird) wrote:
As far as I could tell, it didn't do a thing to my landing roll.

You may not have noticed the increase, but physics is physics. Most
spam cans touch down at about 50 kts, which means a 10 kt tailwind
increases your touchdown ground speed by 20%. Basic physics says that
will increase your ground roll by 44% for the same amount of braking
effort.

Everybody should try some downwind landings, if only to see just how bad
an idea they are. The problem is how. I don't like doing them at
uncontrolled fields, because you're going against traffic. The best way
is to find a towered airport at a time when there's nobody else around
and ask for the downwind runway.