TOST WEAK LINKS.

The BGA now recommend as follows:

"The weak-link assembly incorporates a link to suit the glider being
launched (see Appendix E) and this remains with the parachute assembly.
(At some sites, a selection of weak-links, suitable for launching each of
the glider types in the club’s fleet, may remain permanently attached to the
parachute assembly. This is convenient, but calls for extra care in
ensuring that the correct link is chosen for each launch.)

"N.B. The Tost weak-link system is designed for use either with a single
link or with double links. If the double-link system is employed, it is
essential that the links are of different design (the main link having round
holes and the reserve link having slotted holes). Using two weak links,
each of the same design doubles the breaking load and renders the whole
assembly ineffective. Because of the risk of assembling two weak links
incorrectly, the single-link assembly is recommended as the more foolproof
system."

This is a quote from the BGA Winch Operators Manual , page 20,
http://www.gliding.co.uk/forms/clubm...t/winchops.pdf .

This recommendation was made after an Olympia 463 had structural failure
while being winch launched, and the pilot was killed. It was found that
there was weakness in the wings due to water ingress while in the trailer,
and a double strength weak link had been used; it was not established which
was the critical factor.

This accident was on 13th July 1996, BGA Ref: 79/96, AAIB Ref: EW/C96/7/5.

W.J. (Bill) Dean (U.K.)
Remove "ic" to reply.


"Ian Johnston" wrote in message
news:dzZo7CxomoOm-pn2-1IU6gvmrdIOd@localhost...

On Tue, 5 Jul 2005 15:59:24 UTC, M B
wrote:

Is there any commonly known way to test a weak
link non-destructively (other than launching a glider)?

The Tost system uses two in parallel, one slightly longer than the
other. Whoever hooks up the glider should always check that both links
are intact and that only one is taking the load.

Ian