Actual Rope Break

Andrew,

thank you for your post. It helps to understand "why the rules are the way there are".

On Monday, June 2, 2014 6:50:10 AM UTC+2, Andrew wrote:
Hi Kevin



Congratulations on managing this emergency safely. A low tow

termination of the tow is a true emergency, that some people have

not managed successfully, as discussed on this website.



I've been gliding for a long time, and my experience is that

unplanned tow terminations are very rare. I have only had two

unplanned releases, the lowest at 400ft at Lasham (Euroglide 73),

the other at 1000ft at Portmoak. On the one at Lasham, I was very

aware that the entire competition grid were watching me. Both were

wave-offs, due to towplane engine problems (neither serious as it

turned out later, but the tow pilots were understandably concerned at

the time). My experience seems logical when one considers that after

liftoff, the tension on the rope should be close to the drag on the

glider, i.e. about weight divided by L/D, i.e. about 35lbs or less. Apart

from shocks from slack lines tightening, if the rope doesn't break

during the first few seconds when the glider is being dragged over

the ground, a 'pure rope break' is unlikely. The rope is essentially

'proof tested' in the first 30 seconds of every tow. I haven't had any

ring or tow-mechanism malfunctions. So from my experience, the

most likely (but rare) problem is a tow plane engine problem.



You say you are pleased that you practiced for this. I assume you

mean that you are glad you practiced 180 turns from 200ft. I wish to

say that my personal opinion is that a verbal briefing (to go straight

ahead) would have been much safer for your instructors to teach

you, with a verbal briefing that any other alternatives must be

delayed until high enough for 'some maneuvering'. I'd put that at

300ft minimum, when a 90 turn to look back, and do some thinking,

would be be ok, but even then, a turn away to the safest area should

be made, even if off-field. Otherwise, go more-or-less straight ahead,

and let the insurance company worry about their glider. I'd

recommend that instructors should teach that a low rope break is an

emergency, and the only responsibility on the pilot is to get himself

and his passenger down without harm. Damage to the glider should

not be considered. I obviously don't know for sure, but I think its

arguable that this teaching approach might produce more minor

damage to gliders, but fewer fatalities.



It's not that a typical glider isn't capable, aerodynamically-speaking,

of performing a 180 at 200ft. They obviously can. Its that an early

solo pilot may not be able to, and experienced pilots under that

stress may not be able to either.



Safety is a tricky concept. My view is that, to be safe, one should

'stop before it becomes unsafe'. That sounds obvious, but then

consider that this logically means that we should 'stop while we are

still safe'. Ie..... we should stop when we could have safely gone a bit

further. The price for safety, is to stop too early. I can remember

stopping flying (for weather) knowing people were thinking we could

have safely gone on a bit longer. And they were completely right.

Straining this logic, its arguably safer to teach to go straight ahead,

even if an excellent pilot could do a 180.



I stand by my remark made earlier, that a site where a straight-

ahead landing is likely to produce more than minor damage, is not a

safe site.





At 23:20 01 June 2014, Kevin Christner wrote:

I had my first "rope break" ever today. I was approximately 200-

250ft

abov=

e the ground. Emergency procedures were not a problem.



The Tost released for some reason. Its a nose hook so the back

release

mec=

hanism could not have been the culprit. Further testing with the

wheel

bre=

ak on the ground revealed no problems so I took another tow and

had no

prob=

lems. The ring may not have been engaged properly (doubtful) or

the slack

=

I got in the rope was just too much when it tightened back up

(probable

but=

the release still should have held).



In any case has anyone else ever experienced an actual emergency

unplanned

=

release? In 14 years of flying I have never heard of one. Good

thing we

d=

o practice this. =20



2C