Separation by tower

"Newps" wrote in message
...
I was in position and holding on 34 at Asheville, NC (AVL) today, with a
plane on final, me in position and holding, and a 182 in front of me
taking
off. Before his wheels left the runway, I was cleared for take-off.

The rule is you cannot start your takeoff roll until the required
separation exists. He probably hurried your clearance because of the
plane on final. Having one single chase another down the runway is common
at any busy GA airport. Being 500-700 feet short on separation is a
trivial matter.

My local airport can get busy at times (reasonable amounts of GA, and we
share the airfield with everything up to 767s) but we don't get a lot of
"chasing down the runway". I've had a few "land after"s, but we've got
1,850m of runway and they're no problem (and anyway, it's only an invitation
that one can decline, not an order).

I've not had a take-off clearance when they guy in front still had his
wheels on the runway, but I _have_ had plenty when he was only a hundred or
two feet in the air. And the clearance was always of the form: "Departing
traffic is a C152 [or whatever] turning left on departure; with that traffic
in sight, cleared for take-off ...". I suspect the main thing the controller
needs to be thinking is not so much the formal separation distance, but the
consequences of two single-engine aircraft suffering an EFATO and having to
set down - the last thing you need is a runway with one small "obvious"
EFATO field at the end of it and two aircraft both heading for it at once!
In our case, if you hear the guy in front has a problem and is heading for
the "standard" bit of ground, you probably still have time to abort.

Another poster made the most important point, of course - namely that a
clearance to take off is not an order to do so. Only if you have lined up
under a "line up if able to commence immediate departure" do you have any
compulsion to get your skates on!

D.

"David Cartwright" wrote:
I've not had a take-off clearance when they guy in front still had his
wheels on the runway, but I _have_ had plenty when he was only a hundred or
two feet in the air.

What they do at HPN sometimes is get two spam cans in position and hold at
the same time. If there's two guys ready to go, and the gap in traffic is
just right, they'll have the first guy "taxi 500 feet up the runway and
hold" as soon as landing traffic has crossed the threshold. While he's
doing that, they'll have the guy behind him taxi into position on the
numbers. When the landing traffic turns off the runway, they'll clear the
first spam can for takeoff, and as soon as he's in the air, clear the
second guy with, "maintain visual separation".

It takes a tower controller who's on the ball, and pilots who follow
instructions, but it can mean getting two guys out in a gap that would
otherwise only allow a single departure.

David Cartwright wrote:




My local airport can get busy at times (reasonable amounts of GA, and we
share the airfield with everything up to 767s) but we don't get a lot of
"chasing down the runway". I've had a few "land after"s, but we've got
1,850m of runway and they're no problem (and anyway, it's only an invitation
that one can decline, not an order).

Also remember that as soon as the plane flies off the end of the runway
the separation standard disapperars. So what was once 3000 feet goes to
zero.



I've not had a take-off clearance when they guy in front still had his
wheels on the runway,

Go to any big city airport. You will see jets touching down as the jet
taking off still has his mains on the runway. You will see jets getting
a takeoff clearance as the preceding jet departure is about 5000 feet
down the runway and just starting to come up off the nosewheel.


but I _have_ had plenty when he was only a hundred or
two feet in the air. And the clearance was always of the form: "Departing
traffic is a C152 [or whatever] turning left on departure; with that traffic
in sight, cleared for take-off ...".

He doesn't need to say all that, that's probably why the other guy is
already 200 feet in the air, he's wasting air time. But that happens
everywhere. We have a couple guys here that when they want you to start
a turn early will actually say "when speed and altitude permit start
your crosswind." I just sit there and laugh.




I suspect the main thing the controller
needs to be thinking is not so much the formal separation distance, but the
consequences of two single-engine aircraft suffering an EFATO and having to
set down - the last thing you need is a runway with one small "obvious"
EFATO field at the end of it and two aircraft both heading for it at once!

A plane has an engine failure is an emergency situation and the rules
don't apply if we then have two on the runway. Been there, done that.


Only if you have lined up
under a "line up if able to commence immediate departure" do you have any
compulsion to get your skates on!

Man, that's cumbersome.

On 2/27/05 11:58 AM, in article u_mUd.11119$Ps.4033@okepread06, "J Haggerty"
wrote:


Runway separation requirements are as follows;


3-9-6. SAME RUNWAY SEPARATION

Separate a departing aircraft from a preceding departing or arriving
aircraft using the same runway by ensuring that it does not begin
takeoff roll until:

a. The other aircraft has departed and crossed the runway end or
turned to avert any conflict. If you can determine distances by
reference to suitable landmarks, the other aircraft needs only be
airborne if the following minimum distance exists between aircraft: (See
FIG 3-9-1 and FIG 3-9-2.)

1. When only Category I aircraft are involved- 3,000 feet.

2. When a Category I aircraft is preceded by a Category II
aircraft- 3,000 feet.

3. When either the succeeding or both are Category II aircraft-
4,500 feet.

4. When either is a Category III aircraft- 6,000 feet.

5. When the succeeding aircraft is a helicopter, visual
separation may be applied in lieu of using distance minima.

Thanks folks.
--
Jeff 'The Wizard of Draws' Bucchino

Cartoons with a Touch of Magic�
http://www.wizardofdraws.com

More Cartoons with a Touch of Magic�
http://www.cartoonclipart.com

The answer is 3000 feet between you and the airplane in front of or behind
you.

Tom
"Wizard of Draws" wrote in message
news:BE4695C1.50B5D%jeffbTAKEOUTALLCAPS@wizardofdr aws.com...
How much separation is required by the tower for a/c taking off and
landing?

I was in position and holding on 34 at Asheville, NC (AVL) today, with a
plane on final, me in position and holding, and a 182 in front of me
taking
off. Before his wheels left the runway, I was cleared for take-off. I
didn't
feel that it was any safety issue on an 8000' runway, but it struck me as
something to ask about here, especially since I was the sandwich meat in
the
middle.
--
Jeff 'The Wizard of Draws' Bucchino

Cartoons with a Touch of Magic�
http://www.wizardofdraws.com

More Cartoons with a Touch of Magic�
http://www.cartoonclipart.com

Tom Inglima wrote:
The answer is 3000 feet between you and the airplane in front of or behind
you.

Not always.