markbaur

The October 2002 IRM doesn't have these odious hand-signal restrictions. If there are other SIM or IRM changes you'd like to see, let the USPA S&T committee know: [email protected]. The deadline is 1 May for changes to be considered at the July meeting. Mark

I can see this working for "pull," but I also can it interfering with the two-fingers signal. The student has to decode: does it mean "do the second priority," or does it mean "extend legs?" Mark

I agree. We switched last year to using a fist ("grab") to indicate pull, and an open palm ("touch, without grabbing") to indicate practice pull. I can't imagine switching back. Sometimes we get students who have learned different hand signals, so for a few jumps, the instructors have to adapt. It's not often, though, and after a few jumps, the student doesn't need those hand signals any more. I agree with what one of the other posters said about the tongue-out signal. It's kind of hard-wired for "relax, have fun," and is more effective than the conventional limp hand relax signal. I suppose as more of us wear full-face helmets, the tongue-out signal will disappear. Mark

The AFF Standardization Meeting is intended to standardize AFF instructor rating courses, not AFF. We did talk about standardizing course procedures, but we avoided talking about standardizing course performance standards -- and with the proliferation of course directors there is no longer any way to to make sure the level of difficulty is the same from course to course. Mark

An easy way to check is to lay the canopy on its side, as though you were going to flat pack. If this is true, you should be able to make a triangle from the link up the A-line to the bottom of the canopy, then along the bottom of the rib, then back down the brake line to the link. Does this work with the factory-recommended setting on a Sabre? How about a PDR113 or Tempo 150? Mark

Every freefall skydive starts with a "not there" malfunction. The fix for this malfunction is to pull a ripcord (generic: may be ripcord, pull-out, throw-out). If you don't like the results, then cut away and pull your reserve. Mark

That's close to the 1984 dealer price. It might be worth $600 now, if it is in new condition (no damage from sun, acid, mice, etc.), and if it can be assembled to risers without needing modifications to the brakes and toggles, and if you wanted an accuracy canopy to use when the winds are okay for accuracy jumps, and if you have a container big enough, and if you are small enough for light accuracy wing loading. Is the owner planning to jump it? If he has put 0 jumps on it in nearly 20 years, it probably has no value as a parachute to him. If you really want it, offer him half. Mark

Practice by doing chin-ups or pull-ups until you are able to hold yourself in the up position for 2 or 3 minutes at a time. Mark

How accurate is your drug test? How often will it show a false positive? Mark

The pressure inside a round parachute is the same, whether measured near the apex or the skirt (except for negligible differences caused by Bernoulli effect). It doesn't matter where the holes are; the same amount of air escapes from under the canopy, either through a vent (apex, drive, or steering), or through the big hole at the bottom, that is, under the skirt of an oscillating canopy. Moving the apex vent off-center just means that instead of the apex air going straight up and out, in has a small -- very small -- horizontal vector. On a modified canopy (MC-1, double-L, 7-TU, etc), closing the apex vent entirely would have little effect on the descent rate, since the vent is small compared with the size of the drive and turn vents. Even on an unmodified canopy, there would be little effect, since the apex vent serves first as a means to allow air in during inflation, and secondarily allows easier manufacture. Mark

Moving the apex vent off-center does little to the descent rate. If the apex vent were closed, the air would simply spill out under the skirt. The descent rate under an unmodified T-10 is about the same as a MC-1, even thought the MC-1 has large holes cut in it. Pulling down the risers does reduce forward speed, but since the speed is only about 5 mph to start with, there is not much effect here either. Bottom line: the jumps spent learning these techniques are really just jumps retraining reflexes for a constant-speed descent. Mark

Stain-resistant also means dye-resistant. Experiment first with small pieces of fabric and webbing. I have never seen a nice after-market dye job, even the OD to black that Terry mentions. But I don't recall any harness or container failures from dyeing. I would like to see manuifacturers offer batik in addition to tie-dye! Mark

the contrast between these highly trained, highly motivated soldiers who are subject to random drug testing, and the troops from pre-testing days. Drug testing and safety may not have anything to do with each other, but drug use and reduced safety are definitely related. Mark

http://www.aeroconsystems.com/chutes/p60in.htm Nice troll. These are model rocket recovery parachutes. I can imagine trying to dye a skydiving parachute in a 4-quart bowl, and catching the drips in a coffee can. Mark

I have not found this to be the case. Mark

A basic T-10 is unmodified, no steering toggles. MC-1B ("Bravo") and MC-1C ("Charlie") are T-10s with holes cut in the canopy to provide steering and forward speed. (MC = Maneuverable Canopy; MC-3 is military Para-Commander.) What civilian skydivers know as a "T-10" is either a T-10 that's been modified for sport use, with holes cut in like an MC-1B, or really is an MC-1B. Either way: big, round, green canopy. Mark

The descent rate on MC-1 (commonly known as T-10) canopies is fairly low, but most folks jumping them have little experience with constant-speed descents, and a lot of experience with accelerating descents. As a result, they misjudge the timing of the landing, arriving just a bit later than they expect. Like stepping off a curb you didn't realize was there, even a small misjudgment can be jarring. The reason why pulling the risers down works is because each time you try, you are making another jump and retraining your reflexes. It is the number of jumps, not the riser-pulling, that allows you to make the softer landing. Pulling down the risers tends to make the parachute descend faster, but there is no appreciable rebound when you release them. The most effective way to use this rear-riser technique is therefore to pull down the risers immediately after the parachute is open, and to let up again right away. Do this on every jump, and pretty soon you'll be able to stand them all up (wind permitting.) Mark

The reference is from S.L.A. Marshall, Men Against Fire, first published in 1947. I gave away my copy when I found I wasn't going to be an infantryman any more, but as I recall the historical percentage of infantrymen firing their individual weapons in combat has been about 15% even in the best units. Mark

Okay, looking farther, AC105-2C, section 15-E has examples. Example 5 applies, I think. So by implication, if the area were too small to permit exit and descent over the open area, and landing within it, then authorization would be required. Also, "congested" is not the same as "residential." Mark

I'm looking in FAR Part 105, and I can't find a residential-area restriction on normal skydiving operations. There is a reference to "congested areas" in 105.21, but that applies only to demo jumps. Perhaps someone could find the citation for us. Mark

And your reserve may be on Maillon Rapide links of French origin. You should ask your rigger to open up your rig to check. Mark

You don't need a PRO rating if it isn't a demo jump, but a baseball field might be a small target for you, based on the experience you show in your profile. Mark

You have to tell the FAA at least an hour ahead of time, and you may not create a hazard to people or property on the ground. You must wear a two-parachute, single-harness rig, but the FAA does not require you to use either parachute, as long as you are not creating a hazard. If you are going to compensate the pilot, then the pilot needs to have a commercial pilot license. Make sure your pilot knows the requirements of FAR 105. Mark

Good questions. The FAA doesn't say which component the data card should go with. Since the data card needs to show only the most recent repack, you can even discard the old data card and start over. My preference is for the data card to go with the reserve, unless there has been some container maintenance or alteration entered on the card. Maintaining the velcro is normally a rigger responsibility, but I'd encourage you to try replacing the velcro yourself. If you do, be sure to get a rigger to look at your work. Mark

There is a center to the side area of a canopy. That center is aft of the CG. No need for vertical fins or vertical stabilizers, no need even for stabilizers as are found on most (but not all) canopies. Mark