- Written by Mike Gruwell
I've had some riggers tell me that they don't usually replace the reserve closing loop during each inspection/repack because a new loop stretches and affects the finished look of the rig. Apparently some riggers feel it's the fault of a "stretching" new loop that the reserve pilot chute isn't completely seated or compressed like the prior pack job.
Yet my experience shows that a reserve closing loop made out of spectra Cypres cord and threaded through a Cypres washer can be manufactured and pre-stretched precisely to the desired length. It's just critical that the rigger have a standardized method of construction, measurements and pre-stretching.
The following is the procedure for making a Cypres loop at Chuting Star Rigging Loft. These procedures are for most reserve container systems, but not all. Rigs such as the Racer, Reflex and Tear Drop have other procedures.
For a rig that comes in for an inspection/repack, we first check the closed container to determine if the loop is the appropriate length. If the pull force is high or if the pilot chute is not appropriately compressed, we can plan to make adjustments to the present loop length. The previous bulk management of the reserve parachute can also affect the desired loop length.
We then remove the loop still threaded through the washer for a visual inspection. We are looking for any wear on the entire reserve closing loop that may indicate an issue with the pin, the grommets, the AAD cutter, the reserve container closing loop anchor plate and the Cypres washer.
We also check to see how the loop was attached to the washer, which can affect the length comparison for making the new loop. Some riggers shorten the loop length by placing the tail of the loop underneath a turnback of line on the bottom of the washer and an adjustment must be made in the new loop to achieve a proper base length. If this method was used, check the difference in length from the shortened routing to the standard routing by removing the tail from the turnback.
Then remove the loop from the washer and measure from the top of the knot to the end of the loop. To make the loop the exact same size, construct the new loop 3/8" shorter than the old closing loop.
Fingertrap the new piece of Cypres cord, remove any slack and make a mark 3/8" shorter than the old loop. Make your Cypres cord knots beginning at the mark. Cinch the knots hand tight against each other leaving no slack. I have found that three overhand knots in a row cinch down well together and do not budge once stretched. Airtec documents show a double-overhand knot followed by a single overhand knot.
Thread the Cypres cord through the washer. Seat the knots against the washer and remove any slack by hand through the washer. Place the washer in some type of anchor system that will allow you to stretch the loop with your legs and/or body weight. We use the round holes in the legs of an industrial sewing machine in the loft. Make sure the loop does not get pinched or nicked in the anchor as you tighten. Put a smooth tool in the loop and stretch the loop with your legs/body weight.
Check the loop for damage and the proper length. Impregnate/coat the loop with Airtec's silicone in the appropriate area. Install the new loop into the container and continue on with the inspection/repack of the entire system.
We have also found the 3/8" measurement to work well when constructing a new loop from scratch when you only know the desired finished length. If you want a finished loop of 4.25" then mark the new closing loop 3/8" longer (4 5/8"). Make your knots at the mark, thread through the Cypres washer and stretch. The finished length will be 4.25".
Keep in mind that these measurements work for us at Chuting Star Rigging Loft because we follow the same setup, measurements and procedures each time. You may find that ¼" or ½" is the "magic measurement" for you due to the type of knots or a difference in procedures.
Contact us at 770-445-4000 if you have any questions or need more details. Cheers!