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#11
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Andrew Sarangan wrote:
Rule of thumb for mountain flying is to be *at least* 10% under the max weight. For my cherokee (that tops out at 2400) that means absolutely no more than 2160. As a rule, during the summer I try to keep it under 2100 (thank you, density altitude) No one will fault you for keeping 10% under gross, but I don't think that is really necessary. Most runways in the mountains are plenty long for a 172 or cherokee. If you look up the performance data and add 20% for pilot and aircraft performance, there will not be many runways that are shorter. After all, if a runway is too small for a 172, how many other aircraft can really use that runway? I'm guessing that it's not the runway that's Blanche's limiting factor. I do not fly in the mountains, but I often do fly my Warrior II up around 10,000 ft to get above the weather and the turbulence, not to mention some of the bozos flying pretty-much randomly down at the lower altitudes. Once I get above 6,000 ft or so and am loaded close to my maximum gross weight, especially on a warm afternoon with lots of thermal activity, my Warrior's climb becomes unpredictable. On *average*, I still get the climb rate published in the POH, but sometimes a downdraft will overwhelm me for a few seconds or even a few minutes, and I am unable to climb or even to maintain altitude; other times, I'll shoot up like a rocket when I hit an updraft. That kind of unpredictability does me no harm when the closest obstacle is many thousands of feet below me, but I can see how it would be lot scarier crossing mountain ridges, especially with the stronger downdrafts from mountain waves, etc. Flying a bit under gross, at least in a normally-aspirated 160 hp or 180 hp plane, should give you much more of a fighting chance in a downdraft at high altitude. All the best, David |
#12
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Nicholas Kliewer wrote: Would you suggest that I take the mountain flying course somewhere else? I was wondering about doing it at Salt Lake City or Logan, UT since that's a little closer to the area that I'll be concerned about. If you can find a good course in Logan, that would be a great place to go; much lower than COS. Also, Provo is an easy airport. |
#13
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"Andrew Sarangan" wrote in message om... (Blanche Cohen) wrote in message ... Rule of thumb for mountain flying is to be *at least* 10% under the max weight. For my cherokee (that tops out at 2400) that means absolutely no more than 2160. As a rule, during the summer I try to keep it under 2100 (thank you, density altitude) No one will fault you for keeping 10% under gross, but I don't think that is really necessary. Most runways in the mountains are plenty long for a 172 or cherokee. If you look up the performance data and add 20% for pilot and aircraft performance, there will not be many runways that are shorter. After all, if a runway is too small for a 172, how many other aircraft can really use that runway? We're not talking about unobstructed runways but those that are carved out of the trees. If you only have a 172 or cherokee you need to be at least 10% under gross. You may get it off the ground but if you can't be guaranteed 500 fpm climb you have no business trying a takeoff until it gets cooler or you get lighter. |
#14
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Andrew Sarangan wrote:
(Blanche Cohen) wrote in message ... Rule of thumb for mountain flying is to be *at least* 10% under the max weight. For my cherokee (that tops out at 2400) that means absolutely no more than 2160. As a rule, during the summer I try to keep it under 2100 (thank you, density altitude) No one will fault you for keeping 10% under gross, but I don't think that is really necessary. Most runways in the mountains are plenty long for a 172 or cherokee. If you look up the performance data and add 20% for pilot and aircraft performance, there will not be many runways that are shorter. After all, if a runway is too small for a 172, how many other aircraft can really use that runway? I stand with Blanche on this one... it is NOT a runway length issue. As you state, the mountain runways are long enough. The reason for operating 10% under max gross weight is performance. In the mountains the critical issue is climb performance. The difference between 50 FPM and 200 FPM will allow a great reduction in pucker factor. :-) Best regards, Jer/ "Flight instruction and mountain flying are my vocation!" Eberhard -- Jer/ (Slash) Eberhard, Mountain Flying Aviation, LTD, Ft Collins, CO CELL 970 231-6325 EMAIL jer'at'frii.com WEB http://users.frii.com/jer/ C-206 N9513G, CFII Airplane&Glider, FAA-DEN Aviation Safety Counselor CAP-CO Mission&Aircraft CheckPilot, BM218 HAM N0FZD, 197 Young Eagles! |
#15
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Nick,
If you can get a course , take it. If not, or even if you do take a course, I would recommend Sparky Imeson's "Mountain Flying Bible." It is availaable through the usual aviation catalogues. |
#16
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In article , wrote:
Andrew Sarangan wrote: [snip] No one will fault you for keeping 10% under gross, but I don't think that is really necessary. Most runways in the mountains are plenty long for a 172 or cherokee. If you look up the performance data and add 20% for pilot and aircraft performance, there will not be many runways that are shorter. After all, if a runway is too small for a 172, how many other aircraft can really use that runway? I stand with Blanche on this one... it is NOT a runway length issue. As you state, the mountain runways are long enough. The reason for operating 10% under max gross weight is performance. In the mountains the critical issue is climb performance. The difference between 50 FPM and 200 FPM will allow a great reduction in pucker factor. :-) Jer/ "Flight instruction and mountain flying are my vocation!" Eberhard Of course what Jer/ doesn't mention is that I learned it from him during the mountain flying course! See? I *was* paying attention! |
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