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#51
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Lancair crash at SnF
Senoirs have forulas for breakfast.
Larry Dighera expressed precisely : I know most ng readers hate those darned formulas, but that's the way the world works. |
#52
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Lancair crash at SnF
Seniours kiss their arsess aloha!
Dylan Smith formulated the question : The answer is as always training, and having a plan. Think of the eventualities just as you line up - if you lose power at point X, what should you do. At point Y, what should you do? What about point Z? |
#53
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Lancair crash at SnF
booooooooring
WingFlaps explained on 4/24/2008 : Let's work some real numbers for a 172 at 500'. |
#54
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Lancair crash at SnF
Senoirs think physics is physical booooooring
WingFlaps used his keyboard to write : "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? |
#55
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Lancair crash at SnF
theyr are ignoring u boooring
Larry Dighera pretended : John T. Lowry |
#56
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Lancair crash at SnF
"tman" inv@lid wrote Here's why I wonder about that. Let's suppose 65 KAS before and after a 180 turn from a 10 KT headwind. OK, before the turn, your groundspeed is 55KTS and after the turn your groundspeed is 75KTS. Your intertial frame of reference is tied to the g/speed, not the a/speed. So -- the kinetic energy of the aircraft and contents is about 33% higher (75/55)^2. That energy is only going to come from one place with no power -- trading in altitude (potential energy) for kinetic energy. You should try to get your money back from your CFI. -- Jim in NC |
#57
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Lancair crash at SnF
One way to practice this would be to establish a "runway altitude" at, say, 1000ft AGL, get the airplane into takeoff configuration on heading at that altitude over a road or something, simulate a failure at a specified altitude--say, 1,500 feet--and see what altitude you're at when you get back to your reciprocal heading. If it's above your starting altitude, you made it. Actually this is very similar to how I do have pilots simulate this. However it is often not quite realistic for a couple of reasons. 1. The illusion of speed. When done for real the airplane will seem to be fly much faster than when done close to the ground, especially if there is much wind. I am thoroughly convinced the most stall spin accidents happen for two reasons. A. is the illusion of speed when the pilot thinks the are going faster than the are. B. Is the pilot isn't thinking they are in a situation where a stall is possible, and thus does not recognize it as a stall when it occurs. (Very similar to A) 2. Decent rate. It may be possible to get back to the runway and line up on the runway but not arrest the descent rate. This is especially important in aircraft with higher wing loadings. Make sure that when you about 100 feet above your runway altitude that you are still at you minimum (normal) power off approach speed. True this may be a better option than putting it into the trees but hitting the runway at a high decent rate because you are too slow to round out and flare will probably only be a Fair landing. (Good = Airplane will need some repair, Fair = occupants may need some repair as well) 3. Proficiency. Look back through the group at the arguments for and against power on landings VS full power off. Also look at the arguments for Full Flaps vs Flaps as Needed.vs. No Flaps. If you are one of the pilots where less than 50% of your landings (in the airplane you are flying(Gliders fit here)) are power off then Land Straight ahead should be your only option. Same thing applies if you land with full flaps more that 50% of the time. Again the same should apply if you are not thoroughly familiar with the airplane you are flying. Are you beginning to see why as a rule landing straight ahead is almost always the best option? My mantra to pilots is "an emergency is not the place to be practicing little used skills, try to make an emergency landing as normal as possible" 4. Options. One of the biggest problems with trying to go back to the runway is the commitment to it. Once you commit to it there are usually little else available for options that will have a good outcome. If open fields surround the airport you may have the option of landing somewhere else. But in order to make it back to the runway you will have little time to evaluate any other options, and by the time you figure out it isn’t going to work you will likely be out of airspeed, altitude and ideas. 5. The Pattern. My practice of the maneuver has shown that usually it can be done from 500 feet in most training aircraft if the pilot is proficient in the maneuver and the aircraft. This is why I generally teach to start the crosswind turn at 500 feet. Once you are at 500 feet and have your turn established your chances of making back to the runway usually change from slim to good and it is much more likely that you will be able to make the runway as an option. At this point you are not longer climbing straight ahead and are entering the crosswind. Usually from this point on the runway should be an option if you have a power failure in the pattern. Again proficiency and practice are the key as you will be landing power off, downwind and using flaps as required. 6. Semantics. We tend to say land straight ahead, But I don’t know of any flight instructor that does not teach that a 45 degree change in heading left or right is not appropriate and often desirable when dealing with a power failure immediately after takeoff to take advantage of more desirable terrain. Brian CFIIG/ASEL |
#58
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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." To summarise your missed point, the pilot control inputs cost energy that is not factored into simple glide/time analysis. This is absolutely correct. But then, I dont understand the connection to your first statement regarding the wind. Additioinal drag by control input is completely unrelated to the presence or non-presence of wind. BTW, here's an example of a successful turn back from an engine failure at 400ft! Mind you, this was *not* in a glider, but in an Antonov An-2, pretty much a flying airbrake. And before you ask: Yes, this is an accident report. But it only was an accident because the ground was covered with soft snow so the plane flipped over at touch down. Otherwise, the maneuvre would have been successful. Even so, everybody walked away and the plane is flying again. Here's the link to the report: http://www.bfu.admin.ch/common/pdf/1826_e.pdf |
#59
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Lancair crash at SnF
Brian schrieb:
My mantra to pilots is "an emergency is not the place to be practicing little used skills, try to make an emergency landing as normal as possible" I absolutely agree. But my conclusion is: Practice, practice, practice. Of course this also includes discussing the options during the departure briefing. |
#60
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Lancair crash at SnF
On 2008-04-25, tman inv@lid wrote:
is 55KTS and after the turn your groundspeed is 75KTS. Your intertial frame of reference is tied to the g/speed, not the a/speed. That is so wrong it's not even wrong. The ground isn't even relevant. If it was right, thermalling a glider would be an utter nightmare. -- From the sunny Isle of Man. Yes, the Reply-To email address is valid. |
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