At 15:18 02 June 2014, Bill D wrote:
On Sunday, June 1, 2014 10:50:10 PM UTC-6, Andrew wrote:
Hi Kevin
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Congratulations on managing this emergency safely. A low tow=20
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termination of the tow is a true emergency, that some people have=20
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not managed successfully, as discussed on this website.
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I've been gliding for a long time, and my experience is that=20
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unplanned tow terminations are very rare. I have only had two=20
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unplanned releases, the lowest at 400ft at Lasham (Euroglide 73),=20
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the other at 1000ft at Portmoak. On the one at Lasham, I was very=20
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aware that the entire competition grid were watching me. Both were=20
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wave-offs, due to towplane engine problems (neither serious as it=20
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turned out later, but the tow pilots were understandably concerned
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the time). My experience seems logical when one considers that after=20
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liftoff, the tension on the rope should be close to the drag on the=20
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glider, i.e. about weight divided by L/D, i.e. about 35lbs or less.
Apart=
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from shocks from slack lines tightening, if the rope doesn't break=20
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during the first few seconds when the glider is being dragged over=20
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the ground, a 'pure rope break' is unlikely. The rope is essentially=20
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'proof tested' in the first 30 seconds of every tow. I haven't had
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ring or tow-mechanism malfunctions. So from my experience, the=20
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most likely (but rare) problem is a tow plane engine problem.
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You say you are pleased that you practiced for this. I assume you=20
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mean that you are glad you practiced 180 turns from 200ft. I wish to=20
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say that my personal opinion is that a verbal briefing (to go
straight=20
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ahead) would have been much safer for your instructors to teach=20
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you, with a verbal briefing that any other alternatives must be=20
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delayed until high enough for 'some maneuvering'. I'd put that at=20
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300ft minimum, when a 90 turn to look back, and do some thinking,=20
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would be be ok, but even then, a turn away to the safest area should=20
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be made, even if off-field. Otherwise, go more-or-less straight
ahead,=20
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and let the insurance company worry about their glider. I'd=20
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recommend that instructors should teach that a low rope break is an=20
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emergency, and the only responsibility on the pilot is to get
himself=20
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and his passenger down without harm. Damage to the glider should=20
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not be considered. I obviously don't know for sure, but I think its=20
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arguable that this teaching approach might produce more minor=20
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damage to gliders, but fewer fatalities.
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It's not that a typical glider isn't capable,
aerodynamically-speaking,=
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of performing a 180 at 200ft. They obviously can. Its that an early=20
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solo pilot may not be able to, and experienced pilots under that=20
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stress may not be able to either.=20
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Safety is a tricky concept. My view is that, to be safe, one should=20
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'stop before it becomes unsafe'. That sounds obvious, but then=20
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consider that this logically means that we should 'stop while we are=20
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still safe'. Ie..... we should stop when we could have safely gone a
bit=
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further. The price for safety, is to stop too early. I can remember=20
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stopping flying (for weather) knowing people were thinking we could=20
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have safely gone on a bit longer. And they were completely right.=20
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Straining this logic, its arguably safer to teach to go straight
ahead,=
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even if an excellent pilot could do a 180.
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I stand by my remark made earlier, that a site where a straight-
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ahead landing is likely to produce more than minor damage, is not a=20
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safe site.
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At 23:20 01 June 2014, Kevin Christner wrote:
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I had my first "rope break" ever today. I was approximately 200-
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250ft
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abov=3D
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e the ground. Emergency procedures were not a problem.
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The Tost released for some reason. Its a nose hook so the back=20
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release
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mec=3D
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hanism could not have been the culprit. Further testing with the=20
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wheel
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bre=3D
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ak on the ground revealed no problems so I took another tow and=20
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had no
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prob=3D
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lems. The ring may not have been engaged properly (doubtful) or=20
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the slack
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I got in the rope was just too much when it tightened back up=20
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(probable
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but=3D
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the release still should have held).
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In any case has anyone else ever experienced an actual emergency=20
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unplanned
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release? In 14 years of flying I have never heard of one. Good=20
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thing we
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d=3D
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o practice this. =3D20
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2C
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The rope tension is more than the glider's weight divided by the L/D
which
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would only be the case in level flight. Aero tow is lifting the weight
of
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the glider into the sky which requires more tension.

The record shows premature termination of tow is far more common than you
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uggest. Only one incident I know of involved a rope break in the takeoff
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ll. The rest were rope breaks during the early airborne part of the tow.
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The reason is ropes don't simply snap when overloaded. Fibers break then
t=
he rope unravels which takes a little time. If the rope was overstressed
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n the takeoff roll, expect it to part at few hundred feet AGL.

The 200' AGL 180 turn back to the runway is the MINIMUM STANDARD in the
US.=
Either a pilot learns to confidently demonstrate the maneuver with
grace
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and precision or his flying career stops right there. All pilots are
expec=
ted to retain that level of ability throughout their careers and can
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to be asked to prove it in every Flight Review or Check Ride.

However, demonstrating an ability to perform the maneuver doesn't mean
it's=
required or even the preferred action in a real emergency. It's simply
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additional option in the pilots repertoire. A pilot is expected to
exerci=
se good judgment in selecting the best option for the situation.

That said, if a pilot damages a glider in a risky off field landing when
th=
e glider was in a position for a safe return to the runway, he'll likely
be=
grounded pending a check ride.

Bill, you need to accept that this forum is worldwide. Advice and practice
is different outside the USA. While turn backs may be de rigueur at low
height in the USA they are positively discouraged in the UK and never ever
practiced. People who make low turns receive intensive counseling and/or
remedial instruction.
I would never ever criticise a pilot, or take punitive action for choosing
the option which gives the best chance of survival. Insurance can pay for
damaged gliders, as far as I am aware all the money in the world cannot
resurrect dead people.
You have made it very clear that you feel we are lacking in some way and of
course we think the FAA is barmy, such is life.