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#41
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Navigation flight planning during training
On Mar 13, 8:40 pm, "Andrew Sarangan" wrote:
Thanks for pointing out diversion. But I would consider that to be an argument against doing extensive paper calculations. Diversion is not done with an E6B, plotter and a flight log. It is done by taking a wag at the course and distance, making a reasonable assumption about wind and variation and coming up with rough heading and time. First off, it depends on the diversion. Not every diversion is complete in a matter of minutes, although that is the only kind that gets tested on the checkride. In the real world of flying VFR XC, you may well find yourself diverting to an airport 100+ miles away. Maybe it's to go around weather you didn't expect, maybe it's because headwinds are greater than anticipated and suitable airports are not so close together as one might like, maybe it's because a TFR popped up. In those cases, you should do at least a little calculating. But even a short range diversion is done by approximating the steps that are fully computed in paper flight planning. Now the problem is that most people have a difficult time approximating something they never really learned to do exactly. See Roy's response on this - and I've had the same experience he has. People get out of the habit of doing the full procedure, and then when they need to do an abbreviated, approximate procedure they can't do that either. The ability to take a wag at the course and distance quickly and accurately really only comes from having computed it multiple times and observed patterns. If it were up to me, we would go back to the 30 minute XC plan. That would force the student to keep drilling for speed, and through sheer repetition he would start gettting a feel for what the results ought to be. So the original question still remains. Why not do all ground planning by computer, and if anything unusual happens during flight, fly it like a diversion? Because if you can't do the steps on paper, on the ground, what makes you think you can do them even approximately in flight? It is important to understand why we teach certain things. Most aeronautical information is simply passed down from one CFI to the next, and many things are done by habit instead of reason. I agree. And there are things that I think could be safely dropped from the paper planning process. Compass deviation? Trying to correct out those sub-5-degree errors by looking at a whiskey compass bouncing around in the turbulence? Get real. It may have made sense in the days of dead reckoning hundreds of miles at a time, but those days are gone. These days, we dead reckon at most 50 miles. And the moronic triple-interpolation for takeoff and landing distance in those Cessna books? Waste of time. Round up the temperature and altitude, round down the pressure, and call it good. Gives you a little cushion (little enough, the way most rentals are maintained). But the fundamentals - choosing checkpoints, correcting heading for wind and magnetic variation, estimating climb fuel and cruise fuel - you have to know these things. I have yet to see a convincing argument for the pen & paper method, except for claims that it is 'basic information all pilots should know'. Well, it is. Because without it, the approximate methods used in a diversion will be meaningless (since the student won't understand what he is approximating) and thus quickly forgotten. Not that I'm sure this isn't happening already. Michael |
#42
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Navigation flight planning during training
On 03/13/07 16:57, Andy Lutz wrote:
Thanks for the encouragement. I did sound a bit scared as I read my first post. I have heard about most of the things you mentioned in my reading. I got the test booklet from ASA last year and have read it through a few times. Without the instructor walking with me through it too, it was sounding rather complicated to do spur of the moment. But now that I have a CFI to help explain things one concept at a time, and train to competence as I need it, I should do much better. I guess I'm feeling that more may be expected of me than I think I can do. My instructor, a MCFI, by the way, I trust implicitly. He told me after my last lesson that most people take their check ride at 65-70 hours and he thought I may be ready at 50 or less. That is scary too. But as I said, I trust him and he won't push me beyond what I'm ready for. I want to push out of my mind that 50 hour comment and not expect anything like it, but it threatens to hang aroung and plump my ego, and there is no room for an ego in those small cockpits. Perhaps you should mention to him how is comment affected you. If you would have done better without it, he should know. Consider it "constructive criticism" ;-) I haven't soloed yet and I think I still have a way to go. I expect I'l be sharing about that here when the time comes. OK, for now, just breathe! Take lessons one at a time. I'll worry about not learning what I've been taught, after I've been taught it. Best of luck, and please keep posting. -- Mark Hansen, PP-ASEL, Instrument Airplane Cal Aggie Flying Farmers Sacramento, CA |
#43
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Navigation flight planning during training
Sextant? You had a sextant? When I was a kid, we thought we were lucky if we had an astrolabe. You had stars? |
#44
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Navigation flight planning during training
In rec.aviation.student Michael wrote:
The ability to take a wag at the course and distance quickly and accurately really only comes from having computed it multiple times and observed patterns. If it were up to me, we would go back to the 30 minute XC plan. That would force the student to keep drilling for speed, and through sheer repetition he would start gettting a feel for what the results ought to be. When I was doing my cross-country work, I planned WAY more cross-country trips than I actually went on. Most of the trips got cancelled due to weather. This worked in my favor, in the long run, because I got exactly that repeated drilling in the process. When checkride time came, I had no problem planning the trip (granted, the DE gave me the destination a few days in advance, but I actually planned it that morning, with current weather). And the cross-country part of the written exam was a snap, too. I agree. And there are things that I think could be safely dropped from the paper planning process. Compass deviation? Trying to correct out those sub-5-degree errors by looking at a whiskey compass bouncing around in the turbulence? Get real. It may have made sense in the days of dead reckoning hundreds of miles at a time, but those days are gone. These days, we dead reckon at most 50 miles. The deviation cards in the planes I trained in had very small corrections -- smaller than my ability to hold a heading at the time. When I explained that to my CFI, he didn't hassle me about not having deviation figures in my flight plan. Not to mention, of course, that the actual-vs-forecast winds would probably impact my course by more than the deviation anyhow, in a random direction, which basically makes the deviation figures noise unless they're significant. And the moronic triple-interpolation for takeoff and landing distance in those Cessna books? Waste of time. Round up the temperature and altitude, round down the pressure, and call it good. Gives you a little cushion (little enough, the way most rentals are maintained). Right. People forget why they're doing this. It's not "how much runway do I need", it's "is the runway long enough". In a rental, if you're so close you need to do exact interpolation, then the runway is already not long enough. .... Alan -- Alan Gerber PP-ASEL gerber AT panix DOT com |
#45
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Navigation flight planning during training
In rec.aviation.student C J Campbell wrote:
One bad tendency I have noticed with a calculator is that calculators usually display a level of precision, such as seconds or tenths of a mile, that is pure fantasy. I teach students to round everything at least to the nearest minute and mile. You could probably round everything to five minutes and ten miles and not lose anything significant. One of the hazards of calculators, and of electronic computation in general. Nobody understands the concept of "significant digits" any more. Just last week, I saw somebody build a spreadsheet with single-digit input, but triple-digit comparisons in the output. I had to explain that there was no way that "4.89" and "5.12" were actually different results, and that there was no reason to prefer one over the other based on those calculations. .... Alan -- Alan Gerber PP-ASEL gerber AT panix DOT com |
#46
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Navigation flight planning during training
On Mar 14, 7:32 am, C J Campbell
wrote: However, a student should understand manual flight planning well enough to be able to calculate drift, groundspeed, etc. The fact is, someone proficient with an E6B will always be faster than someone with a calculator. The E6B does an excellent job at depicting the effect of winds visually as well. When I learned manual flight planning, the aim was to teach me how to perform the measurements and calculations by hand. By doing this, I understood the concepts involved in plotting a course, figuring wind drift, magnetic variation, speed and time. Somehow I think that plugging a few data points into a program and looking at the results would not accomplish that goal. It's analagous to handing a third grader a calculator, and telling them not to worry about learning math by hand. By plugging the proper numbers into the calculator, they'll get the right answer, but will miss out on much of the theory behind that answer. By the way, when I took my PPL check ride back in the dark ages, I was expected to do more than just give the examiner a WAG on the diversion. I had to turn towards the alternate using a WAG, then come up with the actual course, distance and time to the new airport. In a real life weather diversion, given the possibility of reduced visibility or low ceilings, the accuracy of that calculation could mean the difference between arriving, or flying past the alternate. John Galban=====N4BQ (PA28-180) |
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Navigation flight planning during training
"Alan Gerber" wrote in message ... Right. People forget why they're doing this. It's not "how much runway do I need", it's "is the runway long enough". There's a difference? |
#48
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Navigation flight planning during training
In rec.aviation.student Stan Prevost wrote:
"Alan Gerber" wrote in message ... Right. People forget why they're doing this. It's not "how much runway do I need", it's "is the runway long enough". There's a difference? Sort of. It's not like you're going to go out and buy a runway that's 1,542 feet long. You're trying to figure out if you can safely use, say, a 2,000 foot runway. So if you're looking at an answer that's in the 1,500-foot range, you don't need to get it exactly. And if the answer is in the 2,500-foot range, you need to do something drastic. So you don't need to interpolate from the tables. Round everything up, and if it still fits, great. If it doesn't fit, but it's close, MAYBE you should go back and do a more precise calculation. Or maybe you should think about reducing fuel, or cargo, or waiting for a colder day. If the rounded-up answer is 1,700 feet, and the "right" answer is 1,461 feet, it's not like you're going to pay extra for the "extra" 239 feet. You might relax a little more, but either way you'll get off the runway OK. .... Alan -- Alan Gerber PP-ASEL gerber AT panix DOT com |
#49
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Navigation flight planning during training
Completely agree with this. One other point I might add is that by
blindly using a calculator or some program that does all the computations for you, it is very easy to become a victim of a "garbage in - garbage out" scenario. I've seen this happen more than once: people would plug in some numbers, get some numbers back, and just take those numbers as the answer, even though they're completely wrong because of an error made in the input. When you do things by hand, you get a much better feel for how sane your results are, because you see all the intermediate steps, and there's many more places that would raise a red flag for you if you made a mistake. Besides, I could never fully trust the completeness and correctness of the airnav data that online planners use: after all, if one blunders into a restricted airspace, or scratches a mountainside because of an error in such a planner's database, that would be pretty sad, and totally that person's responsibility. Andrey In rec.aviation.piloting Alan Gerber wrote: One of the hazards of calculators, and of electronic computation in general. Nobody understands the concept of "significant digits" any more. Just last week, I saw somebody build a spreadsheet with single-digit input, but triple-digit comparisons in the output. I had to explain that there was no way that "4.89" and "5.12" were actually different results, and that there was no reason to prefer one over the other based on those calculations. ... Alan |
#50
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Navigation flight planning during training
On Mar 15, 3:12 pm, Andrey Serbinenko
wrote: Completely agree with this. One other point I might add is that by blindly using a calculator or some program that does all the computations for you, it is very easy to become a victim of a "garbage in - garbage out" scenario. I've seen this happen more than once: people would plug in some numbers, get some numbers back, and just take those numbers as the answer, even though they're completely wrong because of an error made in the input. When you do things by hand, you get a much better feel for how sane your results are, because you see all the intermediate steps, and there's many more places that would raise a red flag for you if you made a mistake. Besides, I could never fully trust the completeness and correctness of the airnav data that online planners use: after all, if one blunders into a restricted airspace, or scratches a mountainside because of an error in such a planner's database, that would be pretty sad, and totally that person's responsibility. Andrey As I mentioned in a related post, I once had a student who painstaking did all the calculations by hand, but everything was reversed by 180- degrees. It was because he was so caught up with measuring the chart and operating the E6B that he missed the big picture. One could argue that had he done it by computer, his brain might have been more relaxted to catch that sort of mistakes. Your point about the accuracy of the online data is a valid point. One cannot be sure if the chart on your screen is the latest version and if it contains all the updates. However, that would only become a problem if you don't carry a real chart with you during flight. Even if the online planner routed you through a restricted airspace, you should be able to catch it during flight. |
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