This video records what can/will/should happen when cable launching with a weak link rated for a lighter glider.
The wrong weak link was attached before the launch due to a mix up changing over from a single seat glider (blue) link to a two seater link (black). I should have verified the correct link was used before being hooked on. I'll add further comments below later on the lessons learned from this experience. As a relative novice pilot, I welcome constructive peer review comments.

So, how did the mix up occur? The comments below were recorded by one of the ground crew (an instructor) assisting preparations.

"You were about to go solo in the DG1000.
The other instructor was trying to remove the blue link from the previous launch of the DG100 [a single seater] but with gloves on and with difficulty. I offered to take over which he accepted.

I removed the the link from the tow rope and gave the link to the other helper. However he accidentally took the main tow rope, not the weak link, and when I realised I was trying to link a black link to a blue link I called him back over and we swapped the tow rope for, what I thought was, the blue link but it was the black link that I must have given him.

I proceeded to couple the weak link to the rope and then proceeded to connect the link to the glider piloted by Mark.

Mark did not request to see the link nor did I offer to show him the link. This is how the blue link got erroneously connected to the DG1000.

After discussions with Mark we both agreed that the checks CB SIFT BEC should have W added which is CB SIFT BECW where W is the check on the weak link. Had that been part of the check list, this would not have occurred."

Launch failures due to any cause are something we train for. Before every launch, we specifically consider possible eventualities such as cable breaks and winch failures and decide on what actions we will take. For low level breaks, landing straight ahead is usually the safest providing the airstrip is long enough. For higher level breaks, the options are more likely to require a turn back and abbreviated or normal landing. Wind strength and direction are also variables that come into the considerations.
For this launch with little or no wind, my options were: land straight ahead (runway 03) if low, do a 3/4 turn and land on the cross runway (29) if above 500-600 feet, or do a more or less normal circuit back to the same runway.
In this event, since it was still quite early in the climb, I elected to land straight ahead. The break occurred with about 450ft indicated (~320ft AGL) and descent commenced from about 600ft. In reality this was probably sufficient height to safely commence either of the other go round options. Once committed to plan A and seeing that a satisfactory aiming point could be identified I stuck with it. However, this did necessitate descent on full airbrakes all the way to the ground which is not entirely ideal.
Lessons learned:
- ALWAYS positively verify the correct weak link. Don't rush this step.This is even more critical in a lighter glider to avoid over stressing risks.
- The cross over decision point between landing ahead and going around may not be easy to judge (probably more so for a novice), particularly in a early climb break
- In spite of the actual or apparent length of the strip available, factors like the narrow section on this vector near the other end and the winch position may mean it's not as long as you think

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