"Best forward speed" approaches

Roy Smith writes:

1) Is there any point in practicing any "best forward speed" approaches
besides the ILS?

It doesn't hurt, but as a practical matter, the only time you'll get
"best speed" requests is at a busy airport with lots of jet traffic,
and in that case, it's almost certain that they're flying an ILS.

You can get the request any time you have aircraft with different
approach speeds and the controller packs things in a little too tight.
Besides, while my home airport has two ILS approaches and lots of jet
traffic, the most common preferred runway is 25, which has only NDB
and LOC(BC) approaches.

Not me. Try it some day in VFR conditions. Fly the glide slope (or
VASI) down to 200 AGL at 120 KIAS with the flaps up, then try to land
and see how much runway you use up.

You use *lots* (I've done it a few times under the hood, and once, at
110 kt, in IMC). Fortunately, you often find a 10,000 ft runway on
the end of an ILS, so there's lots to use. With an ILS on a 5000 ft
runway and a low ceiling, I'd say 'unable' to a request to approach
faster than 90 kt.


All the best,


David

In article ,
David Megginson wrote:

You use *lots* (I've done it a few times under the hood, and once, at
110 kt, in IMC). Fortunately, you often find a 10,000 ft runway on

I haven't done the math, but it seems like if you float down half a 2
mile runway after zooming down the ILS you're not going to be clear any
sooner that if you'd flown the ILS more slowly but made the first turnoff.

Are controllers allowed to let the trailing aircraft get closer to
the end of the runway (with you on it) than they were to you while
you were in the air on the glideslope?

--
Ben Jackson

http://www.ben.com/

Ben Jackson wrote:

I haven't done the math, but it seems like if you float down half a 2
mile runway after zooming down the ILS you're not going to be clear any
sooner that if you'd flown the ILS more slowly but made the first turnoff.

Yes you will. Nothing balls up a sequence like somebody doing 90 knots
over the ground.



Are controllers allowed to let the trailing aircraft get closer to
the end of the runway (with you on it) than they were to you while
you were in the air on the glideslope?

Three miles is the separation unless visual separation is used. If
visual is used there is no separation minima other than don't let them
hit. If the trailing plane is a single than 3000 feet is what's needed,
and you do not have to be off the runway. If it's a twin then it's 4500
and you still don't have to be off the runway. If it's a jet, or some
others like most King Airs, you have to be off the runway.

"Newps" wrote in message
.net...


Ben Jackson wrote:

I haven't done the math, but it seems like if you float down half a 2
mile runway after zooming down the ILS you're not going to be clear any
sooner that if you'd flown the ILS more slowly but made the first
turnoff.

Yes you will. Nothing balls up a sequence like somebody doing 90 knots
over the ground.



Except a 90 kt approach with a 20 kt headwind resulting in a 70 kt
groundspeed

Steve S

(Ben Jackson) wrote in message news:qYx4b.238270$cF.77016@rwcrnsc53...

I haven't done the math, but it seems like if you float down half a 2
mile runway after zooming down the ILS you're not going to be clear any
sooner that if you'd flown the ILS more slowly but made the first turnoff.

Well, let's take a stab at the math. I like my approach speed (whatever
it will be) stabilized outside the FAF. Typical glideslope intercept is
4-5 nmiles. So if I'm slowing, I want to slow down about 6 nmiles out.
That's ~4.5 minutes to DH. OTOH, if I keep my speed to 120 kts, I
can do the same in 3 minutes.

So the question is, does it take me an extra 1.5 minutes to get off the
runway? I don't think so...I can throttle back when I break out and
slip a little bit to scrub speed so I can dump in the flaps. Maybe
an extra 1/2 minute?

But I can see where it *could* take at least an extra minute for
some planes which are slicker or if the pilot is unwilling to just
throttle back.

I also know pilots who want to slow up (if they're going to slow)
way earlier than I do, in which case the time differential is greater.

Cheers,
Sydney

But I can see where it *could* take at least an extra minute for
some planes which are slicker or if the pilot is unwilling to just
throttle back.

Yes, I call it the EDM effect. Once you buy a graphic engine analyiser
and see how fast your engine freezes when you pull power, you'll think
twice before pulling back too far when coming down.

-Robert

Well, I feel vindicated. I haven't changed my let down procedure as a
result of putting in an EDM700. The procedure I was using typically only
cools the engine by a few degrees/minute, about 1/10th the default limit
set on the unit. Basically, I leave the trim alone, which keeps airspeed
more or less constant, and drop about 4" of manifuld pressure without
touching the mixture. With the new engine I have been also reducing RPM
to keep from driving the engine with the prop, in which case I do see a
bit more of a temp drop, but still well under 20 deg/min. 4" gets me a
500 FPM descent without touching anything else, and then putting the power
back in I get back to level flight without ever messing with trim.

"Robert M. Gary" wrote:

But I can see where it *could* take at least an extra minute for
some planes which are slicker or if the pilot is unwilling to just
throttle back.

Yes, I call it the EDM effect. Once you buy a graphic engine analyiser
and see how fast your engine freezes when you pull power, you'll think
twice before pulling back too far when coming down.

-Robert

--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
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