mark

5 would be a better approximation than 7. --Mark

From the video posted on the Firebird website, it looks like the MARD is closer to the freebag than the pilot chute. Is that correct? Or is it just an illusion/perspective thing? --Mark

The Strong Sky Anchor uses a yellow cable and depends on bridle extension/unfolding to pull the cable to release in case of a total malfunction. --Mark

What I hear you saying is that it would be okay to rob USPA members of a few dollars to promote the sport in ways you prefer. Is that right? --Mark

There is no referendum procedure in the USPA charter or by-laws. The vote you propose might be advisory, but would not be binding. --Mark

On the other hand, there is something in post #60 in this thread: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=post_view_flat;post=4900232;page=1;sb=post_latest_reply;so=ASC;mh=25;. --Mark

What evidence do you have of rigs not opening in time? --Mark See post #4 The database that led to the LRO investigation included just 24 fatalities over a period of 12 years. It included 5 cases where the reserve was activated at an estimated altitude of 200-300 feet, and 2 cases where the reserve was not activated at all, either manually or with an AAD. Also 2 cases where camera wings may have interfered with emergency procedures, and at least one where the cutaway altitude was low enough the AAD did not detect firing speed until too late. And one case where the AAD was set to fire at 200 feet -- and did. In that database, harness/container make/model was identified 19 times. The size of the container was identified zero times. That is, there is no way to tell if the containers were too tight, too loose, or just right. The length of the closing loop (which would affect pilot chute performance), method of packing, or other rigging issues was not mentioned at all. In the 14 cases where a reserve model was mentioned, 9 were certificated under TS0-C23c Category B (that is, certificated sometime between 1984 and 1994), and 5 were TSO-C23d (1994 and later). Reserve sizes ranged from just over 100 square feet to around 300. Based on the available anecdotes (I hesitate to call it "data"), there is no identifiable problem with the gear itself. The most common problem is low pull, low pull after cutaway, no pull, or some other version of user error, for which raising pull, decision, and AAD firing altitudes is entirely appropriate. --Mark

What evidence do you have of rigs not opening in time? See post #4 That's it? --Mark

What evidence do you have of rigs not opening in time? --Mark

I have the USPA data set that drove the initial inquiry. The data set does not include any information on rig size. The makes/models of equipment components are represented in roughly the same proportions as market share. The details of the data set are not mine to share. You can call USPA to see if they will share the data set with you. If you have particular questions, please PM me and I will share as much as I can. --Mark

This is an odd result. After 8 seconds you are nearly at terminal. Add a couple of seconds of hesitation and you are at terminal. Your pilot chute should have generated well in excess of 50 pounds of pull at that point, more than enough to extract even the most obstinate bag. It may be that your analysis is correct, but I would also be looking at other possibilities to keep from getting similar results with a smaller canopy. --Mark

Photo 1: pocketed corner on Vector 2. View is inside the bottom left corner of a packed Vector 2. Approximately 1" pocket. Photo 2: pocketed corner on Talon 2. View is the bottom corner of a Talon 2 turned inside out. Approximately 1" pocket. Photo 3: pocketed bottom on Racer, although it's a bit more difficult to tell since it's elegantly done by tailoring the the container rather than just making a corner. --Mark

Absolutely. The correct orientation of the bag gives the PC the advantage of leverage to rotate the bag upright breaking the friction before lifting the bag. I'm not sure this is correct. If it were, Sunpath would greatly prefer bag-grommet-to-reserve-bulkhead/bag-mouth-to-BOC for all its models, including those whose manuals recommend grommet-to-pin. I think the answer most probably lies in the design of the container corners. For most rigs -- Sunpath being a notable exception -- the container corners are wrapped to form a pocket that traps the bag. It used to be that bag orientation was a personal preference. The container bottom generally looked smoother with the bag grommet there instead of bulky, bumpy lines. Fortunately, BOCs came in style and covered the ugly at about the same time as wrapped corners came in style. --Mark

No need to speculate. When was the last time you know of rings stretching or warping? Other than RW-1 rings made in 1981. --Mark

I'm not sure what the point of "turning" is. Did you check to see if the RSL pin was fully seated in its socket? It's possible to partially close the shackle so it appears correct at first glance but will disconnect under load. --Mark

How did you check? --Mark

I meant the marine-eye ripcord and 9-pin that closes the reserve. --Mark

I do not [know] of one who did. Can you give us some examples? Bill occasionally quips that the reason for inventing a Skyhook was because the patent on the 3-ring was running out. As for patent enforcement, you can read here on dz.com about Eric Fradet's vigorous enforcement of his MARD design, including forcing Mirage Systems to withdraw their DRX. Also, with respect to patent enforcement and the Skyhook, it is no accident that all Skyhook systems (UPT, Sunpath, Aerodyne, etc.) include a Collins lanyard and a right-side RSL terminating with a curved closing pin, among other design features. --Mark

The patent has expired. While the patent was in force, other manufacturers paid Bill royalties for the use of his invention. --Mark

Let's imagine you are jumping in Topeka, Kansas. If your skydiving altimeter shows 9500', how far away from the clouds should you be? --Mark

Attached is the fabled USAPR FrankenVoodoo in the later stages of repair. Students replaced the main lift web, reserve risers, front and rear leg straps including pads, both side flaps and both MLW cover/handle pockets. Students also overlaid the reserve side flaps and made reserve and cutaway cable assemblies and housings. It still has the original TSO label and is legally jumpable according to the manufacturer. Students used factory patterns to make the new main container side flaps/riser covers, as well as the handle pockets and leg pads. The harness replacements pieces were reverse engineered from other examples. Some riggers will notice the leg straps are conventional 2-piece (like Talon-2), instead of the "V-Flex" that was standard for Voodoo containers. When the container was substantially complete, we tried moving on to making a canopy. The container was sized for a 107, and we happened to have a Sabre-1 107 handy to copy. We carefully disassembled a rib, upper surface, and lower surface to make patterns. Three different master rigger candidates make three different pattern sets. They were all good students and were careful about laying out the fabric pieces and taking careful measurements. And yet, they all produced different patterns. Short of actually counting out the ripstop boxes, we concluded that we could not produce a reliable replica. We've moved on to other projects. YMMV. --Mark

A few years ago I sent a 1992 VTC2-360 tandem reserve to PD for inspection and recertification. The data cards were incomplete, and canopies built at that time came without a "bowling score" data panel, but I'm pretty sure there were more than 40 packs and more than 25 jumps on it. It came back with a new data panel, with boxes for 40 more packs or 25 more jumps. I don't expect I'll be around to send it back again. At the rate it gets packed and jumped, it will have been in service for 40 or 50 years. That's old. --Mark

There are a few manufacturers who have retroactively established life limits for their equipment. Those life limits are not legally binding, and violating them will not lead to FAA certificate action. But there is additional civil liability exposure from choosing not to follow manufacturer recommendations (recommendations, not legally binding instructions). Some riggers choose to accept the additional exposure, and some do not. --Mark edited because no spell check

Why do you need to know that? Your inspection shows whether the system is airworthy. It doesn't matter who did previous work or when. -Mark

You don't have to use a card supplied by the manufacturer. You don't have to use a Tyvek card. You don't have to use a pre-printed card -- you could just write the required stuff on the back of your business card. --Mark