Fatal crash Arizona

On Monday, May 12, 2014 3:44:51 PM UTC+12, Andrew wrote:
One could say that a site
where a straight-ahead landing from 200ft will certainly result in
more than minor damage, is a site that should not be used.

Wait ... what?

Let's guess some numbers here...

300m for the tug to get off
200m more for it to get to climb speed
700m to climb to 200 ft (60m)
.... rope break ...
100m for the glider to slow to approach speed (while climbing 30m as well, making 90m)
600m for the glider to descend to ground level (worst case 7:1 glide angle with airbrakes)
100m to stop on the ground

Total: 2000m

And that's with a powerful tug, such as a Pawnee.

I've flown from places with such runway lengths (or empty fields beyond). But not many.

Your rule would eliminate at least 90% of the places that gliders fly -- without incident -- in this country.

At our home airfield (which by the way has scheduled Dash 8 flights on the sealed runway which is 1000m from stripes to stripes), gliders are given a 500m grass runway with about 300m more on either end to the fence. And yes, we're going over the fence at not much more than 100 ft if we don't have a headwind. Beyond that is nothing but houses. That's not "minor damage" to go into.

For a low break just after (or before) the boundary, the plan is definitely to turn towards and overfly the sealed runway. Any traffic there can take its chances!! (there are not supposed to be parallel operations) There is 300m width of unobstructed (though not particularly smooth) ground in that direction.

If you actually have the luxury of 200 ft when the rope breaks then better to turn the other way, over the houses, and land on the 300m long crosswind runway (which we use when 12+ knot crosswinds make the main runway too tricky for the tug (gliders cope fine)).

Fortunately we don't have to 'guess' numbers as most gliders have high resolution GPS loggers in them! (Remember to use GPS altitude as your pressure altitude probably lags considerably)

From a random flight of my own (unballasted LS4) I observed I used 750m of grass strip to 200ft height, behind a Pawnee with a 9kt quartering headwind..

Where I fly the training process is, land ahead, land off field, turn around.

On Monday, May 12, 2014 3:04:29 PM UTC+10, Bruce Hoult wrote:
On Monday, May 12, 2014 3:44:51 PM UTC+12, Andrew wrote:

One could say that a site

where a straight-ahead landing from 200ft will certainly result in

more than minor damage, is a site that should not be used.



Wait ... what?



Let's guess some numbers here...



300m for the tug to get off

200m more for it to get to climb speed

700m to climb to 200 ft (60m)

... rope break ...

100m for the glider to slow to approach speed (while climbing 30m as well, making 90m)

600m for the glider to descend to ground level (worst case 7:1 glide angle with airbrakes)

100m to stop on the ground



Total: 2000m



And that's with a powerful tug, such as a Pawnee.



I've flown from places with such runway lengths (or empty fields beyond). But not many.



Your rule would eliminate at least 90% of the places that gliders fly -- without incident -- in this country.



At our home airfield (which by the way has scheduled Dash 8 flights on the sealed runway which is 1000m from stripes to stripes), gliders are given a 500m grass runway with about 300m more on either end to the fence. And yes, we're going over the fence at not much more than 100 ft if we don't have a headwind. Beyond that is nothing but houses. That's not "minor damage" to go into.



For a low break just after (or before) the boundary, the plan is definitely to turn towards and overfly the sealed runway. Any traffic there can take its chances!! (there are not supposed to be parallel operations) There is 300m width of unobstructed (though not particularly smooth) ground in that direction.



If you actually have the luxury of 200 ft when the rope breaks then better to turn the other way, over the houses, and land on the 300m long crosswind runway (which we use when 12+ knot crosswinds make the main runway too tricky for the tug (gliders cope fine)).

On Monday, May 12, 2014 11:13:14 PM UTC+12, wrote:
From a random flight of my own (unballasted LS4) I observed I used 750m of grass strip to 200ft height, behind a Pawnee with a 9kt quartering headwind.

Unfortunately you didn't say how long that took, so we can't calculate how much air you went through. It's going to be a good 30 seconds though, which means probably 850-900m on a no wind day. In an unballasted single seater. My 1200m estimate for a glass twin doesn't seem too unreasonable.

And sometimes (not that infrequently, actually) we do a couple of takeoffs with a light tail wind (5 knots?) before changing ends.