On Tuesday, May 6, 2014 6:20:44 PM UTC-7, Bill D wrote:
On Tuesday, May 6, 2014 5:56:44 PM UTC-6, Don Johnstone wrote:

At 22:22 06 May 2014, Bill D wrote:



On Tuesday, May 6, 2014 2:41:23 PM UTC-6, Don Johnstone wrote:







Frankly I would be horrified to be required to conduct a turn back at



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200ft, I would suggest that this is one of those occasions where the



dang=



er



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of practice is to great to justify.







If you should check out in the USA, you'll be required to demonstrate



compe=



tence in this maneuver. Every pre-solo student is required to do so and



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re than a half century of safety records do not suggest a problem. In



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, even with low performance gliders, there's quite a large safety margin.



T=



he most likely outcome is a pilot will find the glider uncomfortably high



f=



or a downwind landing requiring full spoilers and a slip.







The logic is simple - it's better to have pilots trained for the option.



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o one says a pilot is required to turn back or that 200' is always



adequate=



to do so. What is illogical is to suggest a pilot be required to crash



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unlandable terrain when a safe option exists to land on the departure



runw=



ay.







What are you trying to save? The pilot or the aircraft? The priority should



be survival of the soft bit, that is you and me.



As an instructor with nearly 50 years experience I know that when I



initiate an emergency procedure I do so allowing a margin to ensure my



survival if it does not work out, I have been bold but never certifiable.



Most living instructors have the same survival instinct. That is why I have



lived long enough to do 10,000 launches, and of course landings. It has



already been hinted that the practice you describe involves modifying what



you normally do, in my view that probably makes it pretty useless and not



real preparation for the event. If you did carry out the training in



exactly the same way as the possible real event you might find that the



results were very different, not to mention painful. I will stick with my



300ft thank you, I know it works. Low turns, below that height may have



been acceptable in old wooden gliders, the minimum height in T31 and T21



gliders was 150ft, but for modern glass gliders it is just far too low, you



only have to look at the accident statistics to see that low final turns



figure to a large degree in accidents so why plan for it?



I repeat a controlled descent with wings level is far more likely to have a



better result than hitting the ground in a turn or even worse spinning in



trying to avoid it.







PS Despite all that there have been times when I have initiated a practice



emergency and very quickly wished I had not, no plan survives first



contact.



So, you're saying the pilot will be safer if they don't learn to perform the return to runway maneuver when it's safe to do so?



I can assure you that the higher a glider's performance, the safer it is. It's the old, low L/D gliders that can run out of altitude before getting lined up with the runway.

The discussion seems to focus exclusively on the decision height for a turn around. I think that is only one factor in making this decision. As reported by Bob T there was heavy sinking air on the departure end of the runway. Returning to the airport would have required transiting thru this air a 2nd time, which strikes me as inadvisable without much more altitude than Knauff had.

The other issue is that a tow rope break requires immediate lowering of the nose. This is done routinely at altitude, but at low altitude this means pointing the glider's nose uncomfortably down at the ground while executing a steep banked turn. If the ground is rising, as it is at Sampley, the picture seen by the pilot is even more disturbing. All that it takes is a momentary hesitation in this reflex and the outcome can be fatal.

As an aside, I once did a wind mill start in my DG400 below 1000' (over a runway). This maneuver requires achieving in excess of 90 kt airspeed. Because the engine & prop act like dive brakes, you feel like you are standing on your rudder pedals when you do this close to the ground. I got to this airspeed and the prop still didn't rotate. This meant that I had to steepen the descent even more. All of my instincts said no, but my brain said yes, which is what I did. The engine started, but I decided that this maneuver really needs to be started at a higher altitude.