Double Release Failure

On Sep 8, 8:13*am, tstock wrote:

I've heard some pilots say they would prefer to do an intentional rope
break than to try to land with the tow plane.

* * * * *
And what happens if the rope does NOT break? How is this rather benign
"emergency" magnified?
How many tow ropes /weak links (much) stronger than legal?

I am aware of one documented double release failure in the USA.


Tom Knauff

On Sep 8, 11:21*am, Tom wrote:
On Sep 8, 8:13*am, tstock wrote:

I've heard some pilots say they would prefer to do an intentional rope
break than to try to land with the tow plane.

* ** ** ** **
And what happens if the rope does NOT break? How is this rather
benign "emergency" magnified?

It isn't 'magnified'.

A the correct way to attempt a deliberate rope break is gentle and
safe - far more so than a landing on tow. It's just the regular rope
slack maneuver taught to private pilots without the effort to take the
slack out smoothly plus opening the spoilers. You're aiming for about
10' of slack while in the normal center high-tow position. Once you
have that, open the spoilers and raise the nose as needed to maintain
normal tow position.

If it doesn't work, you still have the landing option. Why not try a
gentle, controlled, rope break first? You might find you have a rope
that breaks easily. If you try the landing option first and it goes
wrong you may never get the chance to break the rope.

How many tow ropes /weak links (much) stronger than legal?

Probably less than the number of understrength ropes/weak links. But
that's a different issue being addressed by regulatory authorities.


I am aware of one documented double release failure in the USA.

That 's one more than I was aware of.

Probably less than the number of understrength ropes/weak links. *But
that's a different issue being addressed by regulatory authorities.


Bill,

Which regulatory authorities and where are they doing the addressing?

On Sep 8, 1:16*pm, FBCompton wrote:
Probably less than the number of understrength ropes/weak links. *But
that's a different issue being addressed by regulatory authorities.

Bill,

Which regulatory authorities and where are they doing the addressing?

The FAA & NTSB based on a conversation during a recent accident
investigation. The NTSB showed up at an accident site that would not
normally be on their radar - i.e. a minor accident with no in-flight
breakup, fire or fatality.

Their main interest was the weak link, ring set and release hook
maintenance/replacement records. They were obviously educating
themselves while building a data set for a report leading to further
action.

Another point which arose in that discussion is that if your POH says
you need a 650 KG weak link with a + or - 10% tolerance for both winch
and aero tow, the old 80 - 200% rule doesn't satisfy that
requirement. In most cases, the POH value falls within the 80-200%
range. but if it doesn't, the POH weak link value trumps the 80-200%
rule.

We lost Captain Curt in Blairstown to a tug upset. Preferring to
stay away from that possibility. I have done quite a few landings on
tow and would gladly do one in about anything I'm familiar with.
Perhaps people who believe that landings on tow are dangerous haven't
done one?
After one LOT in an AS-K21 (during my Commercial check ride prep
with the instructor in the back seat) with tension still on the rope,
the rope would not release from the glider. It turned out the ring was
smaller diameter than standard and the release didn't open enough to
go past center. It would have released in flight, but sitting still it
wouldn't. How far from an in-flight problem was that? New Tost rings
were ordered, and the release cable adjusted.
Jim