mark

If you're going to open up a seam, I'd recommend the closest load-bearing (bottom) seam instead of the tail seam. A typical load-bearing seam is stacked and sewn and therefore easier to reassemble than a tail seam rolled around reinforcement tape. Mark

Or you could take one side of the canopy and flake it exactly right, and take the other side of the canopy and flake it exactly wrong. An over-the-shoulder side pack. Mark

The folks who assert that flaking can extend the life of the canopy don't explain why this is so. When they pack, they push the left side of the center cell fabric in between all the left line groups. When the canopy opens, all that fabric rushes back between the line groups. The same thing happens on the right side. Why is this good? Mark

Bulk distribution. Mark

Source? Mark

Nice aluminum battery box (much better than plastic Cypres-1 box). Anodized in Airtec purple. Excellent cutter. Must calibrate before every jump. No altitude offset possible. No auto-off (Cypres, Vigil, Argus, MarS all turn off at 14 hours); battery life is about 150 hours, which means you should it off after every jump. Batteries are located in the AAD pocket, which means if you leave it on at the end of one weekend, and you don't jump the next weekend, you will need to open the reserve to replace the batteries before the following weekend. Assumes that it is turned on at dz level. Can be turned off and turned on in the aircraft. Do not do this at, say, 7000 feet unless you plan to open at 9000 feet or higher. Functional check (requiring an altitude chamber -- does your rigger have one?) recommended at each repack. Grey area whether 105.43(c) requires the recommended check. Depending on size of cable channels, may require disassembly to install. The control head is substantially larger than the control heads of other AADs. It is possible to open the battery box, unplug the control head cable, run the cable backwards through the channel(s), and then reassemble the cable and close the battery box. Some manufacturers do not approve this model AAD. No tandem, student, or swoop models; no 2-pin models. (? I'm not sure about this; the website says these are in Beta testing, but I don't think they've gotten further than that.) Not waterproof or water resistant. Price comparable to Vigil and Cypres. -Mark

Wayne Snyder has a jump on this one. Mark

I read that. I'm not convinced that difference will be noticeable after taking into account variations like canopy speed, load drag, density altitude, and Coriolis effect. Using your own canopy as an example, exactly how much change in riser pressure would there be by switching to 25" risers. Or, exactly how much change in the angle of attack would there be? Mark

Ok, I'll bite. How much does the angle of attack change if the risers go from 20" to 25"? Alternatively, how much does the force distribution change for such a change in riser length? Mark

According to the Wings sizing chart, a Raven 1 packs about the same as PDR-176. If this is so, an Optimum-193 should fit okay. Mark

You may be thinking of this one: http://www.rigginginnovations.com/Pages/ServiceBulletins/ViewServiceBulletin.aspx?ID=25. The locking loops can take quite a load. Here's a photo of one after a student tried to do a pull-up by holding onto the cable housing. Mark

If you haven't already, you should also report it to Airtec or SSK. Mark

About 200 ft^2. MK-335R is the serial number. An older F-111 canopy. Mark

Except the crossports. The crossports are frayed, especially the ones most outboard. Mark

Military personnel systems (e.g. MC-4/5, etc) can be used by civilians. If the military spec allows a higher pull force, say, 27 pounds, the rig is legal to jump at any pull force from 5 to 27 pounds. There may be a particular military-approved 3-pin container that is okay with a higher pull force than 22 pounds. An MC-3, perhaps. It's up to your rigger friend to provide the citation. Many chest-type reserves are (were) 2-pin systems. Chest reserves are allowed a max pull of 15 pounds. If the 3-pin container is part of a back-type system and the 2-pin container is part of a chest-type, then the 3-pin could be legally allowed to have a higher pull force than the 2-pin. Additionally, there is no maximum pull force specified for opening a main container. Finally, I don't know of any case where pull force is measured at the pin. Mark

TSO-C23f (TS-135), para 4.3.3(b) "a load applied at the handle of not more than 22 lbf (97.9 N), applied in the direction of normal design operation." The note in TS-135 4.3.3.1 states that the seal must be installed. There is similar language regarding pull force, pull direction, and seal for TSO-C23d (AS 8015B, 4.3.2.1 and 4.3.2.5) and for TSO-C23c (AS 8015A 4.3.2.1 and 4.3.2.2). TSO-C23b just says 22 pounds, without specifying direction or seal. The direction of pull in normal design operation is probably straight out (90-degrees from the end of the cable housing) instead of straight down (aligned with the cable housing). Mark

Flammable. Mark

Thanks for your reply. It's been fun reading up on polymer chemistry! What is the plastic bottle made from? Just because something is a solvent doesn't mean it dissolves everything. Water is a solvent, for example. It dissolves stuff like salt and sugar. Poynter suggests using alcohol or lighter fluid to clean oil or grease contamination from nylon, and they work precisely because they are oil solvents. Poynter says further, "Hydrocarbons are not generally injurious to nylon." Windex or other cleaners might attack the coatings on the nylon materials we use, which may affect permeability or UV resistance. That's usually not an issue with webbing or cordura, especially where hot glue needs to be removed. I'd be more concerned about mechanical methods of removing glue. Mark

Windex, and the round end of your 6-inch ruler. Mark

http://www.paragear.com/templates/base_template.asp?group=162#M5995 Mark

The newest TSO standards (C23c/AS8015A, 1984 and later) say the maximum pull force should be measured in the direction giving the highest pull forces under normal operation. This would probably be straight out from the chest. Whether that would be perpendicular to the ripcord housing would depend on the rig design. For sure you'd get a higher pull force if you tried pulling straight up, but that wouldn't be a normal direction. On the other hand, the 5-pound minimum pull force is measured in the direction of easiest pull. Mark

I'm generally in favor of that. Just to make sure we've considered all the possibilities, consider tandem mains, which are not certificated. Do we owe a higher "duty of care" (legal term of art) to tandem passengers than we do to experienced jumpers? Mark

The PIA rigging committee has proposals along these lines; committee members are generally in favor. The FAA has not proposed a whole-sale rewrite of Part 65 Subpart F (which deals with parachute rigger ratings), but we will have something ready to go if they do, or we will be pushing the change ourselves. I'd be happy to hear from the folks who have ideas on what they would change if they were king. Mark Baur PIA Rigging Committee Chair

As a packer, are you responsible for any of the TSO'd components? Mark

Ah, the underworld legions. Every now and then what looks like a typo reveals the truth. Mark