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A few comments on runway length:
I certainly agree with Mark's comments below - I've never seen a time when getting on the ground, realizing there was not enough distance to stop, and then deciding to go around worked. If the remaining distance is so short that the plane can't be stopped after the tires touch it is almost certainly too short to make a successful takeoff. I have read about any number of accidents where the subsequent takeoff was unsuccessful, including one double fatality in a IV.
The traction coefficient between the tire and the runway is certainly better than any other combination available(retracting the gear??) - reminds me of the old biker tale about "laying it down" to stop. Their theory must have been that the traction between skin and pavement was better than rubber to pavement. The tire is the best way to stop the plane. This is, on dry paving at least, irrespective of the size of the tire. Granted, a huge tire with soft rubber might have a slightly better coefficient that our hard rubber, high pressure tires, but not by much(10%?). And it doesn't have much to do with brakes as long as there is enough brake pressure to lock the wheels. In fact the best approach when faced with a real emergency is to just push as hard as you can and lock up the wheels. On dry paving the coefficient doesn't drop off a lot when sliding and the pilot will almost never be able to perform an optimum "anti-lock" function, so there is no point in trying. If stopping on a runway with standing water (or ice) you really do need an anti-skid, but is it worth adding an electronic anti-skid system? I don't think so, but others might disagree. In short, rubber is the best stopping media and the technique is to get the plane on the ground, even if too fast(brakes will slow the plane much more effectively than floating just above the runway), apply the brakes, get the nose down and the flaps up while the stick is held full back and hope for the best. I think you'll be surprised how fast it will come to a stop, although the tires will probably need to be replaced. All you have to do is ride (if you're driving you already know this) a 737 into Burbank to witness the technique in action. Invariably I will here some passenger say "that was a terrible landing" about the time I'm thinking "that was a great landing." Granted, with hard braking there may be only 50% or less of the plane's weight on the mains, but that is still the best way.
In my opinion drag chutes aren't worth talking about, but reverse thrust might do some good, although with the added work load there might not be an improvement in real life("oops, the runway is too short - stand on the brakes, get the flaps up, prop past the detent to reverse, wait for the blades to change, add throttle...oops I'm already stopped"). I don't think the engine would care about having the pitch reversed.
Gary Casey
ES N224SG
Guys,
It takes MORE runway to do a touch and go than to full stop.
I suggest that if anyone wants to experiment with any such techniques they
do it on plenty of runway.
I have flown into runways as short as 1800 ft with trees at both ends. The
minimum runway I need to land, reconfigure flaps, add power and go is more
like 3000 ft.
Also, I think a drag chute would be impractical. By the time you realized
you need it, your speed would be low enough that it wouldn't do much good.
They are for planes that land at 175 kts.
Mark Ravinski
N360KB 1399 hrs
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