PIA Report on low reserve canopy openings

[mathrick 2]

I believe it's ultimately due to the pin being there and keeping it all tensioned. If you pull the pin, the loop is suddenly free on one end, and while it might probably introduce a slight delay, it's going to loosen fast enough for the deployment to happen more or less normally. At least I haven't heard of it happening without the pin being still in place.

This issue was the subject of Mirage SB advising the change of cutter placement, but it's in no way specific to Mirage. Any enclosed PC container can be misrigged that way, as demonstrated by the linked thread video on a Micron. Pop-tops and semi-pop-tops aren't susceptible to my knowledge, as there the pilot is held in place by the loop directly, rather than flaps. One more reason to prefer semi-poptops, aside from superior aesthetics :)

"Skydivers are highly emotional people. They get all excited about their magical black box full of mysterious life saving forces."

[riggerrob 558]

"Snaking" through grommets only occurs when the closing loop is more than 0.5 inches (more than 1cm too long. Then the loop is so long that grommets no longer stack on top of each other and the excess closing loop gets squeezed between the raised edges of grommets, creating enough friction to hold the container closed until you slap it on the side.

Several variables need to all stack - on the wrong side - before a container will hesitate: reserve canopy too bulky, closing loop too long, side flaps allowed to spread until grommets are no longer stacked, cutter low in container, weak pilot chute spring, etc. Improving any of those variables reduces risk.

[skydiverek 54]

VIDEO of too-long-loop cut-lock:

https://www.youtube.com/watch?v=HYIUjKGxagI&fmt=18

[KellyF 16]

peek

I am puzzled by the findings described in the report, that is, "... the Committee Members have yet to locate evidence that supports or indicates a systemic or specific equipment design issue.", considering this video: https://www.youtube.com/watch?v=vaYQ6iP8zlg

The commentary in that video seems to ignore the fact that the jumper is on his back with the reserve PC trying to pull the reserve bag over his left shoulder, likely getting hung up on the jumper's neck and, to some extent, his helmet. The boxed corners of the reserve container had very little to do with the force required to deploy the reserve in this particular case since the bag is getting pulled away from them (referring to the bottom corners, near the center flap).

In regards to the container system in the test with the 18 lb. AAD fire extraction force- someone may have touched on it, but the rate of deceleration of the PC combined with it's state of inflation when it reaches the end of the bridle will have a significant effect on that number. The harder the PC hits the end of the bridle, the higher that number will be, even if the actual force required to extract the bagged canopy from each container is exactly the same. So, that being the case, simply a shorter bridle could give the impression that that particular rig has lower bag extraction forces, and a longer bridle could give the opposite impression.

FWIW, our rig was not System A, and in the AAD test the bag was rotated before the reserve PC was even half inflated.

[JerryBaumchen 1,046]

Hi Kelly,

Quote

in the AAD test the bag was rotated before the reserve PC was even half inflated.

Since you & I watched that video together, I can attest to that in case anyone doubts what you are saying. Also, the bridle line was not in a straight line from the p/c to the d-bag.

Jerry Baumchen

[dpreguy 14]

The report, as I see it says:
,"...did not find any systemic or specific equipment design issues" "...All systems...they function as designed and are within C-23 test program..." "...not been able to determine a definite cause for the LRO(low reserve opening)issue"...

Sounds like all of the rigs tested did OK, but the data shows some performed better than others. And yes, we'd like to know which rig was represented in each data set, but probably won't ever know that. A condition of each mfg to keep this secret?

I was at PIA when the test program was initiated with Dave Singer as the lead. Thanks for all of the efforts.

The LRO issue will apparently continue to be a scary enigma; despite the great efforts of this testing program.

[peek 20]

KellyF

FWIW, our rig was not System A, and in the AAD test the bag was rotated before the reserve PC was even half inflated.

Good to hear.