Help with EGSY 10 Sheffield
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Originally Posted by backpacker
So throttle all the way back, flaps all the way out and then you turn base. Possibly, if you know how to do it safely (try it with an instructor first), S-turns or sideslips. A PA-28, with its almost square fuselage cross section, will have a lot of drag if sideslipped.
Bigfoot - IGNORE the above - you are asking for trouble otherwise, believe me. High drag, coupled with your worry about engine failure (in case you actually had one), will bite you in the ar$e!
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Chilli, I admit I've never been to Sheffield, but the way I read the original question is that the circuit for 10 is over a built-up area with no way to do a forced landing other than on the runway itself. And I read that bigfoot was concious of that, but apparently stayed so high that he overshot.
Now in general, if you're so high that you're likely to overshoot, despite zero throttle, you're going to have to add drag (flaps, sideslip) or extend your flight path (s-turns). Doesn't matter whether the engine is still running or not. A running engine just gives you a way out in that scenario.
Obviously, if you've got nowhere to go in case the engine quit, you never descend below a height where you can reach the runway. But the way I read it, that was not the case here.
I read about a glider instructor once. Before he sent his students solo, he had them to a mock (by walking around on the ground) 1:20 glidepath (the best a glider can do, apparently) and a 1:5 glidepath (the worst a glider can do with the airbrakes extended). He then made sure that the students always stayed in the middle of that, so that they had options.
Same with powered flying. If you're low, you clean up the aircraft and/or you add power. Simple. But if you're high and the throttle is already all the way back, you need to know how to add extra drag to wash off that excess height. Flaps, sideslip and in a true emergency I would even consider asking the passenger to extend that enormous airbrake called the door.
BTW - what's the forums opinion on *removing* flap if you have two or three stages out (base or final) and the engine quits? Me, I would nail the airspeed at 73 knots (PA28 best glide and well above Vs) and carefully raise the flaps to zero degrees if I feel I'm low. Sure, you might lose an initial few feet because of less lift, but with a cleaner airframe the aircraft will glide better. I can always add them back later, or slip off the excess height. And in any case, better hit the hedge at the far end at walking speed than the row of trees at the near end at flying speed...
Now in general, if you're so high that you're likely to overshoot, despite zero throttle, you're going to have to add drag (flaps, sideslip) or extend your flight path (s-turns). Doesn't matter whether the engine is still running or not. A running engine just gives you a way out in that scenario.
Obviously, if you've got nowhere to go in case the engine quit, you never descend below a height where you can reach the runway. But the way I read it, that was not the case here.
I read about a glider instructor once. Before he sent his students solo, he had them to a mock (by walking around on the ground) 1:20 glidepath (the best a glider can do, apparently) and a 1:5 glidepath (the worst a glider can do with the airbrakes extended). He then made sure that the students always stayed in the middle of that, so that they had options.
Same with powered flying. If you're low, you clean up the aircraft and/or you add power. Simple. But if you're high and the throttle is already all the way back, you need to know how to add extra drag to wash off that excess height. Flaps, sideslip and in a true emergency I would even consider asking the passenger to extend that enormous airbrake called the door.
BTW - what's the forums opinion on *removing* flap if you have two or three stages out (base or final) and the engine quits? Me, I would nail the airspeed at 73 knots (PA28 best glide and well above Vs) and carefully raise the flaps to zero degrees if I feel I'm low. Sure, you might lose an initial few feet because of less lift, but with a cleaner airframe the aircraft will glide better. I can always add them back later, or slip off the excess height. And in any case, better hit the hedge at the far end at walking speed than the row of trees at the near end at flying speed...
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Even with the engine still running normally in a single I wouldnt put flaps down unless I knew I was going to be able to reach the runway, dont know about anyone else but at least that absolves you from having to worry about wether or not to take them up again! Which incedentally I wouldnt like to do! Just out of interest how old was the glider!?
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Originally Posted by Backpacker
what's the forums opinion on *removing* flap if you have two or three stages out (base or final) and the engine quits? Me, I would nail the airspeed at 73 knots (PA28 best glide and well above Vs) and carefully raise the flaps to zero degrees if I feel I'm low.
Classic Human factors scenarios always prove that, in moments of high stress, we always revert to what we are first taught. Now, as nowhere in engine failure was "putting the flaps away" mentioned the chances are you won't remember to do it, and won't recognise the cause of your adverse descent rate. Fly the circuit the way I said in my initial post and you won't have to go down that road. If you are that cool that you are likely to do what you have suggested in the time available then you truly are a flying god
And the last glider I flew had a glide angle of 1:42 (Was an instructor before powered flying)
Last edited by Chilli Monster; 9th May 2007 at 14:41.
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A few weeks ago we had our annual target landing practice at our club again. The aim is to land not more than 25 meter after the (displaced) threshold. You get three tries, one of which has to be a glide-in (ie. no power allowed anymore after passing 500 feet). Oh, and the place where your wheels *finally* touch the ground counts, so bouncing is out of the question.
Once you commit yourself to the glide, you regulate your airspeed/glide path with the only means of adding/removing drag you have: with the flaps. If you're high, lower the flaps, if you're low, raise them again. Works just like a handbreak in a car. (Fortunately the PA-28 has manual flaps, making this very easy.)
Needless to say, there is an instructor, acting as a safety pilot, in the RHS.
Once you commit yourself to the glide, you regulate your airspeed/glide path with the only means of adding/removing drag you have: with the flaps. If you're high, lower the flaps, if you're low, raise them again. Works just like a handbreak in a car. (Fortunately the PA-28 has manual flaps, making this very easy.)
Needless to say, there is an instructor, acting as a safety pilot, in the RHS.
The Original Foot
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I was always told that....
....once the flaps go in, they're in and you loose any benefit by taking them out again (particulary in relation to forced landing). Now I am a PPL and can have my own opinions, if I was doing a forced landing and say I misjudged the wind and was reasonably high on my glide, I would drop them out if I felt I had put them in too early. I suspect I would leave them alone if I was down below say 500 ft ! Just a thought really, I have never practiced it.
Not something that has bothered me on this problem so far, however....
Thanks for the contributions to date, I am finding this really useful.
Maybe one for the new aviations quotations:
PPRuNe - therapy to counteract effects of the LHS
Not something that has bothered me on this problem so far, however....
Thanks for the contributions to date, I am finding this really useful.
Maybe one for the new aviations quotations:
PPRuNe - therapy to counteract effects of the LHS
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The only difference is the distance you should be from the airfield if your circuit is at 1,700' instead of your "normal" 1,000'. The angle between you and airfield should remain the same. I'd suggest that you should also look at the "picture" more when doing a normal circuit and then replicate that at EGSY. But as somebody has said earlier, it takes a lot effort to miss a 1,200M runway and may I suggest that your money would not be wasted on a bit of instruction. You'll find that very quickly they'll identify your problem and give you a permanent, worthwhile fix and boost your confidence and ability.
PM
PS. And gliders I have flown have been able to do close on 60:1 at 60kts, but it was some time ago...
PM
PS. And gliders I have flown have been able to do close on 60:1 at 60kts, but it was some time ago...
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Bigfoot01, we fly into a lot of short strips here that surrounded by trees etc and the best approach that we have found is to fly a standard circuit, no matter what the circuit height is, the higher you are the further away you will be from the field, and that will give you a slightly longer final approach, stabilise your speed early on final and control rate of decent with power, apply final flap once you are sure you can get in safely..squeek it in sweetly
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....once the flaps go in, they're in and you loose any benefit by taking them out again (particulary in relation to forced landing)
Using flap adds drag and increases rate of descent. If you maintain the speed, you can retract the flaps again without any sink, provided you adjust the attitude correctly as you do it.
In a normal landing, you would normally reduce speed when you use the flaps and hence people say that retracting is a bad idea: either you'll lose height because you need to dive slightly to regain airspeed, or you'll lose height because you don't regain airspeed and hence have a higher angle of attack and more drag.
In a glide approach, I tend to use flap as needed but keep the airspeed at the clean best glide speed until I'm sure I'm going to make it to the field and can safely slow down. That way I still have the option to lose the flap and extend the glide if I need to. With practice though, you'll find you can judge it pretty well anyway.
M.
