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#51
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"Chris OCallaghan" wrote in message
om... Flying head down is never necessary. The center of the finish cylinder is almost always close to some visible marker on the airport. If it isn't, I ask the CD to move it so it is. My software beeps when I cross the boundary of the cylinder, does yours? Finally, I only glance at the computer once in a while to see if I'm falling below glide slope, which I'd also be doing with a 50 foot gate. But then again, I'm not anal about finishing at precisely 500 feet... I don't agree. When you approach a cylinder, you are aiming at its center. I haven't seen a computer program that optimizes the point on the cycliner you should be aiming at given current position and altitude and interpolates your desired finish height to that point. I'm not a mathematician, but I think you'll find that the point you should be aiming for on the cylinder is on the line from your current position to the center of the cylinder. Since, as far as I know, your computer is guiding you towards the center of the cylinder from your current position, then you will cross that optimal point. Instead you are looking down as the distance clicks off, and checking your altitude to make sure that you don't fall slightly short. I'm not worried about falling slightly short, since I'm nearly always 500 feet or more above the minimum finish altitude. Frankly, if your computer can't help you navigate to the desired height at the edge of the cylinder, yell at the designer, or get a new instrument or software. This isn't rocket science. BTW, if you look carefully at SSA contest rules 10.9.3, it states quite clearly that a finish is recorded when you enter the 3 dimensional cylinder. It does not say you have to enter at the edge, you can also enter through the bottom. What this means is that even if you cross the edge of the cylinder at lower than the minimum height, as long as you can pull up and get a single fix within the cylinder, you've got a finish. Now, some buttheads somewhere will no doubt start coming in below the cylinder and pulling up through the center, figuring this will give them a speed advantage. It won't, since while you finish time is recorded where you enter the cylinder, your finish distance only goes to the edge. As noted in earlier threads this means more heads down and more variations in traffic height and speed, all converging on a much smaller area (the optimum point on the cylinder). If everyone is coming from the same final turnpoint, then they will all converge on pretty much the same point, whether using a finish gate or a cylinder. When everyone is not coming from the same final turnpoint (i.e. an MAT), everyone still converges on pretty much the same point with a finish gate, but they do not converge with a cylinder. Again, the advantage of a finish cylinder is that those people who have sufficient energy (and don't feel the need to make low pass), end up overhead the airport well over 500 feet, at a comfortable speed, with plenty of time to assess the traffic situation, watch out for those on marginal glides, go through their checklist, etc. This has worked very well at every contest I've flown in that used a finish cylinder. The only recent contest where I've felt stressed/hurried during finishes, was one where a few traditionalists browbeat the CD into using a GPS finish gate. Be careful when citing book and passage from the FARs. I know for a fact that you don't follow some rules (none of us do) as scrupulously as you are applying them in this case. I can find some gray in 91.119. You'll be hard pressed to find any in 91.155. The original quote from your message was: As for the FARs, aircraft regularly take off and land withn 500 feet of people, structures, and other aircraft at commercial airports. This is by necessity. And my point was, yes indeed, this happens, and it's perfectly legal according to 9.119. Virtue: the behavior we demand of others, but excuse the lack of in ourselves. The only virtue that I request of others on this group is that they actually read and consider what is said... Marc |
#52
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IMHO mid air collisions are the worry.
The closer to VNE you fly the simpler the lookout and collision avoidance issue (with respect to other gliders) becomes. Close to the ground there is less chance there is of hitting a glider in the blind spot below you. There are generally more gliders around an airfield then anywhere else. Ergo, if you want safe finishes, (including avoiding close outlandings) you want to get gliders back low and fast and look at the issue as one of flow control i.e. does everyone know where to go and what to do after the finish pull up. This is, in effect, what has been informally and safely sorted out by pilots and comp directors for decades. A close remote high finish potentially leaves a number of gliders milling around at or below normal circuit height getting in each others way and increases the collision risk. John Galloway |
#53
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What if there were a few kids on all the available fields, and you had no
other landing options? Would you have made a low pass to clear the field? What if you had never done one before because you viewed low passes as irresponsible? And your point is? |
#54
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Here is what the local FAA Saftey inspector from the FSDO told me less
than a month ago. "Just about everyone likes to do a low pass once in a while. I have even done one in a my Aeronca champ, but no one noticed. The FAR's say 500 feet from any man made object, except for takeoff and landing. Precedince is a fence post is a man made object. However an occasional low pass safely done over a runway will usually not get the FAA's attention. However repeated low passes will result in a visit from you local FAA inspector and possible certificate action" That is right from the FAA and perhaps not word for word but you get the idea. It may be interpreted differently at different FSDO's. But it seems to mee that our FSDO has a very common sense approach to this subject. Brian Case CFIIG/ASEL Andy Blackburn wrote in message ... Let's assume, for the sake of argument, that the interpretation of the FAR's is correct - that busting 500' is, without exception, a violation in any circumstance other than final approach to landing. It is not clear to me that this is necessarily the case, or enforced that way by the FAA, but put that aside for now. If we are going to abide by the letter of the law on FARs, then busting 500' agl ANYWHERE on course should be grounds for penalty. This could be DQ for the day, scoring as if you landed at the spot where the infraction occurred, or whatever is consistent with other FAR violations under contest rules. I believe this would include low saves as well as ridgeline crossings and ridge soaring, etc. In other words, we would need to enforce a 500' agl hard deck in the scoring programs, which would need to include an accurate terrain elevation database. I suspect this is technically not that hard to do since programs like SeeYou already have it. Before going down that path, however, I would want to see a definitive statement from official FAA sources that this is in fact the correct interpretation of the FARs AND that the FAA intends to enforce these FARs to the letter of the law, rather than only in those instances that show some form of recklessness beyond the technicalities alone. It would be a pity in my view if this happened as I really like mountain flying and ridge soaring. 9B At 19:00 03 October 2003, George William Peter Reinhart wrote: JJ, You have a very good point. Why not handle violations of the FAR's same way as busting 18K? No score for the day (or maybe DSQ for the contest). Rules violations used to be handled that way at the sailboat races in times before political correctness was so much the vogue. Cheers!, Pete JJ Sinclair wrote in article ... I flew the 111 at Mountain Home ('72-'74) We have established that the 50 foot gate VIOLATES the FAR's, So what are we going to do about that? We have established that some pull-ups VIOLATE the FAR's, So what are we going to do about that? We have established that finishing over people, VIOLATES the FAR's, So what are we going to do about that? JJ Sinclair |
#55
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At 19:06 05 October 2003, Marc Ramsey wrote:
I'm not a mathematician, but I think you'll find that the point you should be aiming for on the cylinder is on the line from your current position to the center of the cylinder. Since, as far as I know, your computer is guiding you towards the center of the cylinder from your current position, then you will cross that optimal point. This is correct - the shortest distance to the cylinder is on a radial from the center. Frankly, if your computer can't help you navigate to the desired height at the edge of the cylinder, yell at the designer, or get a new instrument or software. This isn't rocket science. I think the point is navigating to a point in space requires monitoring glide angle to the 500'/1mile point. I am aware of computers that beep when you cross the cylinder, but not of any that tell you along the way if you are GOING TO make it. This is what requires the heads-down time. Or leaving a minute or so of time on the clock for enough extra altitude to not have to worry about it. Also, the 'get a new computer' point contradicts the purported logic for recent rules changes (such as 15 min) - that it excludes some pilots from competition to require the 'latest and greatest' computer technology. I don't buy that logic and it looks like you don't either, but it is out there. BTW, if you look carefully at SSA contest rules 10.9.3, it states quite clearly that a finish is recorded when you enter the 3 dimensional cylinder. It does not say you have to enter at the edge, you can also enter through the bottom. What this means is that even if you cross the edge of the cylinder at lower than the minimum height, as long as you can pull up and get a single fix within the cylinder, you've got a finish. Now, some buttheads somewhere will no doubt start coming in below the cylinder and pulling up through the center, figuring this will give them a speed advantage. It won't, since while you finish time is recorded where you enter the cylinder, your finish distance only goes to the edge. Actually, I think the optimal is to be close to zero feet just before 1 mile, then do a ballistic pullup (to roughly zero mph - depending on initial speed) right at 500' and 1 mile (kind of like pole vaulting). This presumes you carry extra potential energy on the glide as a buffer. Otherwise the optimal is to fly Mc speed corresponding to your last climb right to the 500'/1 mi point. If you hit a little sink you could do a mini-ballistic pullup at the edge or go hunting for lift (at 500'). This potential practice is the logic behind John Cochrane's finish donut suggestion - the cost of which is even more pressure on heads down computer time to clear the 1-mile deep donut and/or trying to find lift to reach the bottom of the cylinder. I am not recommending any of these techniques - it's just what the rules encourage the foolhardy (or desparate) to try. At least with the finish at ground level at the airport you have a continuous visual reference as to whether you are gaining or losing on the glide angle, keeping the pilot's head out of the cockpit - that's the main point. 9B |
#56
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#57
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"Robert Ehrlich" wrote in message ... Andy Blackburn wrote: ... This is correct - the shortest distance to the cylinder is on a radial from the center. ... Not correct if there is some cross wind. I can understand a crosswind changing the required heading, and even the optimum speed to fly, but how does it change the distance? Tim Ward |
#58
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Andy Blackburn wrote:
... This is correct - the shortest distance to the cylinder is on a radial from the center. ... Not correct if there is some cross wind. |
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