Post by Tom Goodrick on Jan 29, 2009 21:28:35 GMT -5
(Hopefully Bill can put a copy of Allen's note starting the Dead Stick thread either above or below this entry).
In regard to Allen's "Dead Stick" note, there are several interesting aspects we can discuss with examples.
It is a very good idea for everyone flying FS to put in some time flying the Schweizer glider. Gliding is real flight in its own right. Note that the pilot of that Airbus 320 had significant time in gliders. I am sure that played a part in his success. Another reason is that gliding to a landing is the only thing you can do when flying a single engine plane when the engine quits. So every pilot is given some level of training in flying the plane with essentially zero thrust. They are taught to pick a suitable landing site within range and glide to it. Usually this ends when the instructor pushes the throttle in and says "Ok go around." When I was nearing the end of my training, my instructor did and said that but the engine promptly quit. We were at about 100 feet. I passed through a narrow gap in some trees and landed on the snow-covered field I had picked. I followed some faint tracks from a tractor across the field. It was not too different from landing the J-3 on a snowy field as a kid. You watch your airspeed and don't get real slow until the wheels are about to touch. We got the engine started (a little carburator ice) and took off, following the contour of a hill until clear of terrain.
As a kid (in 1957-58) I was taught to fly every landing in the J-3 as a dead stick landing. You almost have to because there are no flaps. Later when I took formal lessons in a Cessna 150, I was taught the new (1972-73) FAA approach where power is used to maintain a very shallow approach. One problem with this is that you will usually land short of the engine dies. The final profile you fly without power is at least twice as steep as you fly in a normal landing. That is why many pilots do poorly when the engine quits.
In my engineering work, I spent a few years studying gliding flight. Hear are some basic truisms about gliding flight:
1. Speed always degrades the glide ratio. There is a best glide speed for every aircraft about 25-35% above stall speed for the weight and configuration.
2. Gliding is a balance in energy exchange. Gravity puts energy in and drag takes it out. Lift gives you a chance to manage the path to a limited extent. As initial energy (gained by use of power) decays, you can gain some range. But after the speed gets close to the best glide speed, you must just keep it steady. Never try to "extend the glide" at that point by pulling back on the stick. It can get you a few extra feet but then you stall and drop in. Many fatal accidents happen when people do this 100 feet over the trees.
The best way to learn about this is to do it on the simulator. Find what works and what does not. Use the glider and then use any power aircraft. You should even try making "dead stick" landings in twins because that can happen. Running out of fuel or losing power due to contaminated fuel can turn off both engines at the same time. It is rare but has happened to many people, especially when visiting distant airports where fuel is of questionable quality. Twins are really bad at gliding.
Most aircraft, particularly airliners, have ways to keep power for controls long enough to make an emergency landing. Batteries keep running, hydraulic accumulators retain power and the A320 even has a fan/generator they can lower that will give them additional control power.
In regard to Allen's "Dead Stick" note, there are several interesting aspects we can discuss with examples.
It is a very good idea for everyone flying FS to put in some time flying the Schweizer glider. Gliding is real flight in its own right. Note that the pilot of that Airbus 320 had significant time in gliders. I am sure that played a part in his success. Another reason is that gliding to a landing is the only thing you can do when flying a single engine plane when the engine quits. So every pilot is given some level of training in flying the plane with essentially zero thrust. They are taught to pick a suitable landing site within range and glide to it. Usually this ends when the instructor pushes the throttle in and says "Ok go around." When I was nearing the end of my training, my instructor did and said that but the engine promptly quit. We were at about 100 feet. I passed through a narrow gap in some trees and landed on the snow-covered field I had picked. I followed some faint tracks from a tractor across the field. It was not too different from landing the J-3 on a snowy field as a kid. You watch your airspeed and don't get real slow until the wheels are about to touch. We got the engine started (a little carburator ice) and took off, following the contour of a hill until clear of terrain.
As a kid (in 1957-58) I was taught to fly every landing in the J-3 as a dead stick landing. You almost have to because there are no flaps. Later when I took formal lessons in a Cessna 150, I was taught the new (1972-73) FAA approach where power is used to maintain a very shallow approach. One problem with this is that you will usually land short of the engine dies. The final profile you fly without power is at least twice as steep as you fly in a normal landing. That is why many pilots do poorly when the engine quits.
In my engineering work, I spent a few years studying gliding flight. Hear are some basic truisms about gliding flight:
1. Speed always degrades the glide ratio. There is a best glide speed for every aircraft about 25-35% above stall speed for the weight and configuration.
2. Gliding is a balance in energy exchange. Gravity puts energy in and drag takes it out. Lift gives you a chance to manage the path to a limited extent. As initial energy (gained by use of power) decays, you can gain some range. But after the speed gets close to the best glide speed, you must just keep it steady. Never try to "extend the glide" at that point by pulling back on the stick. It can get you a few extra feet but then you stall and drop in. Many fatal accidents happen when people do this 100 feet over the trees.
The best way to learn about this is to do it on the simulator. Find what works and what does not. Use the glider and then use any power aircraft. You should even try making "dead stick" landings in twins because that can happen. Running out of fuel or losing power due to contaminated fuel can turn off both engines at the same time. It is rare but has happened to many people, especially when visiting distant airports where fuel is of questionable quality. Twins are really bad at gliding.
Most aircraft, particularly airliners, have ways to keep power for controls long enough to make an emergency landing. Batteries keep running, hydraulic accumulators retain power and the A320 even has a fan/generator they can lower that will give them additional control power.