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#21
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Lancair crash at SnF
Buttman wrote in news:fuqg20$hee$2
@registered.motzarella.org: On Thu, 24 Apr 2008 17:05:06 +0200, Stefan sayeth: Brian schrieb: Your right in that many aircraft it is possible. But the problem is it isn't possible for many pilots when the engine quits. It is not a maneuver that is routinly practiced. Now this problem could be solved. You're suggesting instructors practice engine failures with their students on takeoff? Oh boy, better hope Dudly doesn't see this... Good god you're a moron. No wonder flying skills are going down the toilet. Bertie |
#22
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Lancair crash at SnF
On Apr 25, 2:06*am, Shirl wrote:
Shirl wrote: A Lancair crashed just moments after takeoff here in Mesa, Arizona, today, too. Plane was headed for California. There was smoke trailing from the plane on takeoff and controllers cleared them to turn back around and land. They tried -- they made the left turn but crashed into the orange orchard. Three fatalities, all in their late 20s. Sympathies and prayers to the families. WingFlaps wrote: When will pilots learn to stop trying to do the impossible turn... and go for a straight ahead landing on soemthing horizontal? In this case, straight ahead would have been into a shopping center, buildings, houses, etc. *Having been through an engine failure, I try not to second guess, but he *may* have thought he had a better chance to at least turn away from all that. I had a look on Google earth and there seem to be many fields around the airport what shopping center are you talking about? Cheers |
#23
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Lancair crash at SnF
On Apr 25, 3:12*am, Dylan Smith wrote:
On 2008-04-24, Brian wrote: Depends on what you mean by "the impossible turn". If you mean turning back at 200 AGL, yeah, that one's pretty much impossible. If you mean 600 AGL, it's pretty much possible in the average aircraft. (Hell, that's pattern altitude at EFD!) The line lies somewhere in between. It is statements like this that get pilots killed. It's statements like 'never turn, always land straight ahead' that also gets pilots killed. There are plenty of airfields where going straight ahead is quite possibly the worst option, and the best survivability options are at least a 120 degree turn away from whatever point you're at when at 600' AGL. The only thing you can do is use the best judgement at the time. You get one chance - it may be wrong. Sometimes, trying to turn back might be wrong. Sometimes doing anything *other* than trying to turn back might be wrong. In gliders, every glider pilot is taught "the impossible turnback" from 200 feet (which, in the typical low performance training glider, is about equal to turning back at 600 feet in a C172). It's the L/D that makes it much harder in a typical powered plane. This means that all manouvers lose energy much faster. The turn back needs at least 2 turns as well as acceleration if there is any wind. You will note that nearly all the accidents are stall spins -a moments thought about the situation will make you realize why this is. The turns are made tight because there is not enough height/time for a lazy turn. Let's work some real numbers for a 172 at 500'. Say climb was a Vx 59 knots. The plane must first be accelerated to 65 for best glide. The pilot carries out some trouble checks say 10s. Calls on the radio =10 s and plans his return. Note that 20s have probably elapsed. The plane has already travelled ~0.4 miles and at a 10:1 glide ratio has lost 200' (assuming he did get it to best glide in the first place). Can he make 2 turns and land back -no way! Ah you say, I'm a much better pilot, I would loose not more than 10 seconds in starting my turn back., trimming etc. But how much does the turn back cost? Assuming you keep to 45 degrees of bank to stay _above_ stall (the stall is now damn close -better hope there's no significant wind) the turns are still going to cost you 35 seconds. 45 seconds lost = 450 feet! Now we add in the energy losses from having to accelerate with the wind and to glide speed. It's still an impossible turn. Try to tighten that turn more and you have to dive to accelerate to avoid the stall and what does that do to your energy management and turn radius? Now what safety margin is appropriate for you and you PAX? Say 100% in that case, unless you've climbed to 1000' don't even think about turning back but practice spotting good landing sites. I've also heard a lot of BS in this thread about not having good palces to put the plane. There is nearly always somewhere flat to put the plane within 90 degrees of the runway centerline -even a road. Malls have big parking lots! Put it down flat in landing config and you will probably survive, stall spin and you'll DIE along with your PAX. A good pilot looks at the airport environs in a strange airport and may ask about options at the runway end for this emergency. Cheers |
#24
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Lancair crash at SnF
On Apr 25, 6:24*am, Andy Hawkins wrote:
Hi, In article , * * * * * wrote: On Thu, 24 Apr 2008 17:05:06 +0200, Stefan sayeth: Brian schrieb: Your right in that many aircraft it is possible. But the problem is it isn't possible for many pilots when the engine quits. It is not a maneuver that is routinly practiced. Now this problem could be solved. You're suggesting instructors practice engine failures with their students on takeoff? Oh boy, better hope Dudly doesn't see this... EFATO practice is normal during the PPL in the UK (simulated, obviously). The instructor chops the throttle and you pick a landing sight and get set up for it in much the same way as you would a PFL. You do have a bit of warning when he announces 'fanstop' over the radio though! The call here is "simulated failure, call climbing" Cheers |
#25
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Lancair crash at SnF
WingFlaps wrote:
I've also heard a lot of BS in this thread about not having good palces to put the plane. There is nearly always somewhere flat to put the plane within 90 degrees of the runway centerline -even a road. Malls have big parking lots! I don't know about where you live, but malls here have lots of light poles, concrete islands, park-and-rest benches and ... and ... vehicles everywhere. And having gone through it once, I'm no longer fooled by what *looks* "flat" at 500, or even 50 feet. |
#26
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Lancair crash at SnF
WingFlaps wrote:
I had a look on Google earth and there seem to be many fields around the airport what shopping center are you talking about? They took off 22L. I'm talking about the new Walmart shopping center. Witnesses said had he not turned, that's where he would have gone. That area *had* many fields that have recently been developed/built-up very recently. I don't know how old the Google Earth photo is. I'll go have a look. |
#27
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Lancair crash at SnF
WingFlaps schrieb:
(the stall is now damn close -better hope there's no significant wind) .... Now we add in the energy losses from having to accelerate with the wind and to glide speed. Arrrgh! Not the old "turn into downwind" legend again! Better work out your understanding of physics before publicly reasoning about turns. There is nearly always somewhere flat to put the plane The operative word in this sentence is "nearly". |
#28
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Lancair crash at SnF
On Apr 25, 10:16*am, Stefan wrote:
WingFlaps schrieb: (the stall is now damn close -better hope there's no significant wind) ... Now we add in the energy losses from having to accelerate with the wind and to glide speed. Arrrgh! Not the old "turn into downwind" legend again! Better work out your understanding of physics before publicly reasoning about turns. Try reading the statement again, here it is: "Now we add in the energy losses from having to accelerate with the wind and to glide speed." Now perhaps you would like to revise some physics and try to critcise it for us? I await your stumbling analysis of my words with mild amusement. Cheers |
#29
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Lancair crash at SnF
WingFlaps schrieb:
Try reading the statement again, here it is: "Now we add in the energy losses from having to accelerate with the wind and to glide speed." Now perhaps you would like to revise some physics and try to critcise it for us? It's the "having to accelerate with the wind" part which is complete BS unless I completely misunderstand what you are trying to say. |
#30
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Lancair crash at SnF
On Apr 25, 10:48*am, Stefan wrote:
WingFlaps schrieb: Try reading the statement again, here it is: "Now we add in the energy losses from having to accelerate with the wind and to glide speed." Now perhaps you would like to revise some physics and try to critcise it for us? It's the "having to accelerate with the wind" part which is complete BS unless I completely misunderstand what you are trying to say. The latter I think. The imposed accelerations associated with the change in direction (from upwind to downwind) require control inputs that add drag and increased energy loss (from drag). To summarise your missed point, the pilot control inputs cost energy that is not factored into simple glide/time analysis. Cheers |
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