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01-21-2016, 04:39 AM
#1
On Reserve
Thread Starter
Joined APC: Jan 2016
Posts: 10
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I am not a pilot, nor could I ever get a pilot's license because of physical health problems.
But I have a question for pilots'. Specifically in relation to commercial air travel. It is more of an opinion request.
My physical health problems include epilepsy. My seizures are completely under control. So here is the reason for my question.
If I am a passenger on a passenger plane, and the steward/ess starts yelling over the PA in the plane. For anyone that knows how to fly a plane because something incapacitating both the pilot and first officer. Regardless of the fact that I have not had any formal flight training and, even if no other passenger stands up. Should I not stand up, because of my epilepsy.
I understand how planes fly.
1. When a plane inclines(nose-up attitude), just like a car. It slows down. When it declines(nose-down attitude) it picks up speed.
2. The air and engine power are inversely proportional to eachother i.e. thinner air allows for greater engine performance. But also means a loss of lift. Whereas, Thicker air means poorer engine performance while greater lift.
3. If the plane decompresses for some reason. Below 10,000ft., won't require the oxygen masks.
4. A passenger plane is not like a military combat aircraft. So, It can't climb vertically, fly upside down, do barrel rolls, or fly as fast.
5. The power a plane is putting out. Is controlled by the thrust levers. On landing a plane has to decrease thrust, to keep from running off the runway. In much the same way, that a car has to slow down for a turn on a public road.
6. Changing direction, by incline/decline is 'affected' by pulling back/pushing forward on the control column. Changing direction by turn/bank is by the turn of the wheel. Just like a car.
7. Planes with four engines, can still fly on three. A plane with three engines can fly on two. A plane with two engines can fly on one engine. In every situation it means increasing the power on the remaining engines, to account for the one engine that is 'out of order' and shut down.
8. Re-directing the fuel for the shutdown engine. To the remaining engine(s) via a cross-feed valve.
9. The lowering of the wheels prior to landing and the raising(flaring) of the plane's nose during landing. Along with flaps amd brakes. Are all meant to help slow the plane down during landing.
10. 250mph is too fast to land(the plane could run off the runway and/or the landing gear could collapse from the speed). 150mph is correct.
So, Despite knowing all that. Even if a steward/ess requests' help. I should ignore them because of my epilepsy, like people with disabilities can't be in the military?
But I have a question for pilots'. Specifically in relation to commercial air travel. It is more of an opinion request.
My physical health problems include epilepsy. My seizures are completely under control. So here is the reason for my question.
If I am a passenger on a passenger plane, and the steward/ess starts yelling over the PA in the plane. For anyone that knows how to fly a plane because something incapacitating both the pilot and first officer. Regardless of the fact that I have not had any formal flight training and, even if no other passenger stands up. Should I not stand up, because of my epilepsy.
I understand how planes fly.
1. When a plane inclines(nose-up attitude), just like a car. It slows down. When it declines(nose-down attitude) it picks up speed.
2. The air and engine power are inversely proportional to eachother i.e. thinner air allows for greater engine performance. But also means a loss of lift. Whereas, Thicker air means poorer engine performance while greater lift.
3. If the plane decompresses for some reason. Below 10,000ft., won't require the oxygen masks.
4. A passenger plane is not like a military combat aircraft. So, It can't climb vertically, fly upside down, do barrel rolls, or fly as fast.
5. The power a plane is putting out. Is controlled by the thrust levers. On landing a plane has to decrease thrust, to keep from running off the runway. In much the same way, that a car has to slow down for a turn on a public road.
6. Changing direction, by incline/decline is 'affected' by pulling back/pushing forward on the control column. Changing direction by turn/bank is by the turn of the wheel. Just like a car.
7. Planes with four engines, can still fly on three. A plane with three engines can fly on two. A plane with two engines can fly on one engine. In every situation it means increasing the power on the remaining engines, to account for the one engine that is 'out of order' and shut down.
8. Re-directing the fuel for the shutdown engine. To the remaining engine(s) via a cross-feed valve.
9. The lowering of the wheels prior to landing and the raising(flaring) of the plane's nose during landing. Along with flaps amd brakes. Are all meant to help slow the plane down during landing.
10. 250mph is too fast to land(the plane could run off the runway and/or the landing gear could collapse from the speed). 150mph is correct.
So, Despite knowing all that. Even if a steward/ess requests' help. I should ignore them because of my epilepsy, like people with disabilities can't be in the military?
01-21-2016, 05:26 AM
#2
Disinterested Third Party
Joined APC: Jun 2012
Posts: 5,347
In an emergency, all the rules that used to apply, don't apply.
The idea that a flight attendant would ask someone to come forward and fly the airplane is a common fantasy that many people have, or have had. It's the quintisential hero fantasy, similar to saving the day in a restaurant when someone's choking, or stopping a bank robbery, or being the only person in the room who knows to cut the blue wire as the clock counts down to zero.
To address your questions, or points in order, bearing in mind that flight attendants don't yell:
1. Yes, nose-up, with no power change, the airplane slows down and gains altitude. Nose down, it can descend and increase speed. There's a lot more to it, of course, and there are airspeed and operating limits that mean one could stall or enter mach buffet by raising or lowering the nose at the wrong time. Doing so with the autopilot engaged may result in fighting the autopilot, which has actually lead to loss of control of the aircraft and in at least one case with a Chinese 747SP, a stall, spin, and permanent damage to the airframe. You've got the general principle, though.
2. Thin air makes for lesser engine performance, not better. The reason that we operate turbine aircraft at high altitudes has to do with efficiency; we get higher true airspeeds (how fast the airplane is really moving, vs. what the instruments tell us)...we go faster. The engines can be operated at higher power settings at high altitudes, and we can fly at higher true airspeeds without bumping up against aircraft limitations such as airspeed limits. Turbine engines need to operate at fast rotational speeds and higher power settings to be their most efficient (power output per gallon of fuel burned). At low altitudes, they put out so much thrust that the aircraft will go too fast, when operated at high power settings; thrust must be reduced, the engine operated at lower rotational speeds and power settings, and the engines are much less efficient. We generally try to climb high as quickly as possible, and stay there as long as possible, which allows us to go as fast as possible (within limits); this is to cover as much ground as possible for each gallon of fuel burned. It's a bit more complicated than that, of course, but you get the idea.
In an emergency, one usually won't be pressing on to the destination. Fuel economy may not be the priority. Then again, it might, depending on the circumstances.
3. With a depressurization at altitude, especially a rapid depressurization, it's important to get to a lower altitude as soon as possible. More important than that is that the flight crew get on their oxygen as quickly as possible, go to the emergency 100% setting immediately, and follow emergency descent procedures. Passengers aren't provided the same kind of masks or pressure oxygen system that the pilots have, and instead receive oxygen that's not under pressure. If the depressurization occurs at a high altitude (35,000', for example), chances are that the passengers are going to pass out anyway, on the way down, even though they have oxygen. They may have 100% oxygen, but there's insufficient air pressure to get it into their blood stream as they breathe.
Generally we try to get down to 14,000 as rapidly as possible, but it depends on the terrain below, as well as where the flight is at the time. At low altitude, with a long distance to cover to get to a landing site, fuel consumption could be a big issue with something like an oceanic crossing; the flight circumstances determine the proper course of action, and it changes with the needs of the flight. You're correct, however, that generally below 10,000, supplementary oxygen isn't needed.
4. Commercial passenger airline aircraft have much lower structural limitations than fighter aircraft so generally speaking, one shouldn't fly inverted or attempt vertical flight (or do loops or barrel rolls). Commercial aircraft are designed to fly fast, but there are limits (and they change with altitude and flight conditions); the speed limit as the aircraft climbs to high altitudes, or descends from a high altitude is actually a moving target; it's a mach operating limit that remains a fixed value, but a changing airspeed. It's still a limit that's much lower than some tactical aircraft, so no maneuvering to avoid phantom fighter jets while doing that depressurized descent to safety.
5. You've got it; reduce power for landing, though if you've flown commercially, you may have noticed that sometimes power is increased during the approach to land, or shortly before landing; power is used as needed up until reaching the runway. Then it's usually brought to idle, and the airplane landed. Power may appear to increase rapidly just after landing. In this case, the power levers have been brought to idle, and sometimes the same levers, or different ones, are brought into a "reverse" range, where the engines use thrust differently in order to help slow down. In this case, power actually increases again, but the thrust from the engines is diverted to the side, or sometimes even forward, to help slow the airplane. Cars don't have that feature. Brakes are also used, just like cars. In airliners, an automatic braking feature is used, giving a setting that slows the airplane at a specific rate. This heats up the brakes. When reverse thrust is applied, the aircraft still slows at the same autobraking rate, but less brake is used, so the brakes don't get as hot.
6. Pull back to go up, push forward to go down, and move the control wheel, or yoke, left and right to bank the airplane. None of those will turn the airplane, though. Pitching the nose up by pulling back increases the angle between the wing and the airstream, and that angle changes the lift created by the wing as well as the line of thrust, and that in turn changes the aerodynamics and creates a climb, assuming excess thrust exists for the new condition. The opposite applies for descending.
Banking, which is turning the wheel left or right, doesn't actually turn the airplane. Lift acts upward when the airplane is flying level, but when the airplane is banked, some of that lift isn't acting upward, but to the side to which the airplane is banked, and it "pushes" the airplane, resulting in a turn. The steeper the bank, the tighter the turn. Much of the time, airliners are restricted to about 25 degrees of bank by autopilot limitations, passenger comfort, etc. With small amounts of turn, less bank is often used.
Aircraft also have rudders, which don't turn the aircraft either, but do affect the turn to some degree. In small airplanes, the rudders are used by the pilot quite a bit. In large airplanes, not nearly so much, and their function is sometimes more automatic. They can be thought of as "quality" devices that improve the condition of the turn by accounting for something called "adverse yaw." Adverse yaw is caused by the ailerons and swept wings in a jet...the ailerons are moved by the control yoke when turned left or right. It's all interconnected; one thing affects another. A bit more complicated than a car, but you've got the general idea.
to be continued...
The idea that a flight attendant would ask someone to come forward and fly the airplane is a common fantasy that many people have, or have had. It's the quintisential hero fantasy, similar to saving the day in a restaurant when someone's choking, or stopping a bank robbery, or being the only person in the room who knows to cut the blue wire as the clock counts down to zero.
To address your questions, or points in order, bearing in mind that flight attendants don't yell:
1. Yes, nose-up, with no power change, the airplane slows down and gains altitude. Nose down, it can descend and increase speed. There's a lot more to it, of course, and there are airspeed and operating limits that mean one could stall or enter mach buffet by raising or lowering the nose at the wrong time. Doing so with the autopilot engaged may result in fighting the autopilot, which has actually lead to loss of control of the aircraft and in at least one case with a Chinese 747SP, a stall, spin, and permanent damage to the airframe. You've got the general principle, though.
2. Thin air makes for lesser engine performance, not better. The reason that we operate turbine aircraft at high altitudes has to do with efficiency; we get higher true airspeeds (how fast the airplane is really moving, vs. what the instruments tell us)...we go faster. The engines can be operated at higher power settings at high altitudes, and we can fly at higher true airspeeds without bumping up against aircraft limitations such as airspeed limits. Turbine engines need to operate at fast rotational speeds and higher power settings to be their most efficient (power output per gallon of fuel burned). At low altitudes, they put out so much thrust that the aircraft will go too fast, when operated at high power settings; thrust must be reduced, the engine operated at lower rotational speeds and power settings, and the engines are much less efficient. We generally try to climb high as quickly as possible, and stay there as long as possible, which allows us to go as fast as possible (within limits); this is to cover as much ground as possible for each gallon of fuel burned. It's a bit more complicated than that, of course, but you get the idea.
In an emergency, one usually won't be pressing on to the destination. Fuel economy may not be the priority. Then again, it might, depending on the circumstances.
3. With a depressurization at altitude, especially a rapid depressurization, it's important to get to a lower altitude as soon as possible. More important than that is that the flight crew get on their oxygen as quickly as possible, go to the emergency 100% setting immediately, and follow emergency descent procedures. Passengers aren't provided the same kind of masks or pressure oxygen system that the pilots have, and instead receive oxygen that's not under pressure. If the depressurization occurs at a high altitude (35,000', for example), chances are that the passengers are going to pass out anyway, on the way down, even though they have oxygen. They may have 100% oxygen, but there's insufficient air pressure to get it into their blood stream as they breathe.
Generally we try to get down to 14,000 as rapidly as possible, but it depends on the terrain below, as well as where the flight is at the time. At low altitude, with a long distance to cover to get to a landing site, fuel consumption could be a big issue with something like an oceanic crossing; the flight circumstances determine the proper course of action, and it changes with the needs of the flight. You're correct, however, that generally below 10,000, supplementary oxygen isn't needed.
4. Commercial passenger airline aircraft have much lower structural limitations than fighter aircraft so generally speaking, one shouldn't fly inverted or attempt vertical flight (or do loops or barrel rolls). Commercial aircraft are designed to fly fast, but there are limits (and they change with altitude and flight conditions); the speed limit as the aircraft climbs to high altitudes, or descends from a high altitude is actually a moving target; it's a mach operating limit that remains a fixed value, but a changing airspeed. It's still a limit that's much lower than some tactical aircraft, so no maneuvering to avoid phantom fighter jets while doing that depressurized descent to safety.
5. You've got it; reduce power for landing, though if you've flown commercially, you may have noticed that sometimes power is increased during the approach to land, or shortly before landing; power is used as needed up until reaching the runway. Then it's usually brought to idle, and the airplane landed. Power may appear to increase rapidly just after landing. In this case, the power levers have been brought to idle, and sometimes the same levers, or different ones, are brought into a "reverse" range, where the engines use thrust differently in order to help slow down. In this case, power actually increases again, but the thrust from the engines is diverted to the side, or sometimes even forward, to help slow the airplane. Cars don't have that feature. Brakes are also used, just like cars. In airliners, an automatic braking feature is used, giving a setting that slows the airplane at a specific rate. This heats up the brakes. When reverse thrust is applied, the aircraft still slows at the same autobraking rate, but less brake is used, so the brakes don't get as hot.
6. Pull back to go up, push forward to go down, and move the control wheel, or yoke, left and right to bank the airplane. None of those will turn the airplane, though. Pitching the nose up by pulling back increases the angle between the wing and the airstream, and that angle changes the lift created by the wing as well as the line of thrust, and that in turn changes the aerodynamics and creates a climb, assuming excess thrust exists for the new condition. The opposite applies for descending.
Banking, which is turning the wheel left or right, doesn't actually turn the airplane. Lift acts upward when the airplane is flying level, but when the airplane is banked, some of that lift isn't acting upward, but to the side to which the airplane is banked, and it "pushes" the airplane, resulting in a turn. The steeper the bank, the tighter the turn. Much of the time, airliners are restricted to about 25 degrees of bank by autopilot limitations, passenger comfort, etc. With small amounts of turn, less bank is often used.
Aircraft also have rudders, which don't turn the aircraft either, but do affect the turn to some degree. In small airplanes, the rudders are used by the pilot quite a bit. In large airplanes, not nearly so much, and their function is sometimes more automatic. They can be thought of as "quality" devices that improve the condition of the turn by accounting for something called "adverse yaw." Adverse yaw is caused by the ailerons and swept wings in a jet...the ailerons are moved by the control yoke when turned left or right. It's all interconnected; one thing affects another. A bit more complicated than a car, but you've got the general idea.
to be continued...
01-21-2016, 05:58 AM
#3
Disinterested Third Party
Joined APC: Jun 2012
Posts: 5,347
7. Airplanes with multiple engines can operate on less engines, and we do spend much of our time when training with an inoperative engine. Engine failures are quite rare, especially in turbine airline aircraft, but they do happen. Airline aircraft must be able to fly and climb with an engine inoperative, and we plan every takeoff with the idea that an engine could fail at the worst possible time. We plan for a failure at a low speed when we must stop on the runway, and we calculate the distance. We also plan for failures at higher speeds on takeoff, when we must continue the takeoff with that engine failed. An engine failure on takeoff is the worst possible time to lose an engine, so we focus on that in our planning.
A four engine airplane such as the Boeing 747 can lose an engine and continue flying, and it flies well on one engine. Loss of a second engine, especially on the same side of the airplane (both engines on the right wing, for example) is a big problem, though the airplane does remain controllable and can be landed. In training, we do cover making a two engine approach and landing, in the 747. That's as far as we go, however, and we don't train for three engines failed, or even four engines failed. It's happened...there have been extremely rare cases in which 747's lost all four engines due to volcanic ash, but again, it's very, very rare.
You may have heard the old joke about the man who hears the announcement from the captain that an engine has failed, but don't worry, we have three more, and we'll be an hour late. Some time later, a second announcement arrives that we've lost a second engine, but don't worry, the airplane flies fine on two engines, and we'll be two hours late. Some time later, another announcement comes; we've lost a third engine, we're okay, but we'll be three hours late.
The man turns to his traveling companion and says "great, if we lose the last one, we'll be up here all day."
One engine, not a problem. Two engines, it's a problem, but we can manage. We're diverting, landing, but we can do it. Three engines is a big problem. Four engines, we're going swimming or it's going to become a fairly short flight. Ironically, the 747 glides well for such a large airplane. There are fewer and fewer four engine airplanes, however, and the two-engine airplane is favored today.
We have multiple engines in aircraft partially for redundancy and safety, but primarily for performance. More thrust means greater performance. Today we have aircraft such as the 777 which don't use more engines, but bigger engines. If an engine is lost, there's only one left, but it's also a much bigger engine.
Losing engines isn't just a matter of losing thrust. Engines provide a lot of other things that are used in flight. We have hydraulic pumps that are used to operate flight controls, flaps, spoilers or speed brakes, landing gear, etc. We use compressed air from the engines ("bleed air") for pressurizing the airplane, heating cabin air, protecting the wings from ice in clouds, pressurizing oil and hydraulic tanks, etc. Engines have generators that supply large electrical loads that do everything from operate flight controls in some aircraft to light the cabin, power the radios, etc. On a large four engine airplane, losing an engine means losing a hydraulic system, a power source, bleed air, etc. That engine also uses oil to warm the fuel, which is important at high altitudes when fuel gets cold (and thick, and can develop ice in fuel filters and engine fuel controllers). Losing an engine affects many more things than just losing thrust.
8. That brings us to your statement on re-directing fuel. You're absolutely right. Fuel must be redirected in order to keep the amount of fuel in the wings balanced, and to ensure that the remaining engines have enough fuel. Multiple fuel tanks are used in large airplanes; they may be in the wings, in the fuselage, and sometimes even at the back of the fuselage. It's important to know where the fuel is and to manage it properly during the flight. Cross feeding, cross flowing, etc is important. With loss of an engine, fuel heating can also be important.
9. You're right; getting the landing gear lowered for landing is important, and it does provide drag which helps slow the airplane. The landing gear has airspeed limits; lowering it at too high a speed can damage some parts of the airplane, so it's important to stick to the limits. If an engine (or multiple engines) is inoperative, one may want to delay lowering the landing gear in some cases. There are other situations on short flights in heavy aircraft when one delays raising the landing gear, and lowers it early, to help cool the brakes.
10. 250 mph is usually too fast. The actual landing speed depends on weight and air temperature, runway conditions, and the elevation (or altitude) of the airport. Before beginning our descent from our cruise altitude, we do calculations to determine the proper speed for landing. We look at the weight we anticipate for landing, and along with the other factors just mentioned, calculate the speeds for extending flaps, and for actually landing. That speed also determines the amount of braking we'll need, along with the distance we need to get down and get stopped. Too fast and we will need more distance, and will have hotter brakes. Too fast and we may not get stopped. Brakes that get too hot may not work, either. There isn't one specific speed for landing, but it depends on the conditions of the flight.
If you can help in an emergency and you know what to do, you should help as much as you're able. Bear in mind that it's rare that there aren't several pilots riding on an airliner; in most all cases there are pilots riding in passenger seats, and often on a spare seat in the cockpit, as we go home or to work, and there are often private or commercially rated pilots on board, too. It would be very rare that both pilots in the cockpit are incapacitated, and there's nobody else on board who could fly the aircraft. Also bear in mind that if both pilots are incapacitated, it's unlikely the flight attendant would know...and the cockpit door is locked from inside.
Epilepsy doesn't take away from your ability to be a valuable and contributing member of society. It may affect what you can and can't do. We all have limitations. Most heros in the world go unrecognized, and they're found in every walk of life. Some of the most critical roles in the world aren't the most dramatic, but they're the most important. Deep down we'd all like to be something larger than life. I'd love to be a Navy SEAL. I've worked with them, have a great deal of admiration for them, but I won't ever be remotely anything like them, and that's okay. Some of the people I most look up to in the world are teachers. You don't need to perform a walter mitty fantasy of saving the day in an airliner to be important or valued, however, and you can and will contribute to the world by being you. I used to wish I could do something big, like most boys and young men. Something big turned out be having kids of my own, and leading a basic life; sometimes the biggest things are found in the most common elements of life. They don't make stories or movies about them, not always, but they're still some of the most critical building blocks of our daily lives. If you get the chance to save the day on an airliner and you're asked to do so, then step forward. But if you're never asked to do so, as 99.999999% of us will never be asked to do, then don't worry. You've got plenty in your life that will be just as heroic; the trick is learning to recognize it.
A four engine airplane such as the Boeing 747 can lose an engine and continue flying, and it flies well on one engine. Loss of a second engine, especially on the same side of the airplane (both engines on the right wing, for example) is a big problem, though the airplane does remain controllable and can be landed. In training, we do cover making a two engine approach and landing, in the 747. That's as far as we go, however, and we don't train for three engines failed, or even four engines failed. It's happened...there have been extremely rare cases in which 747's lost all four engines due to volcanic ash, but again, it's very, very rare.
You may have heard the old joke about the man who hears the announcement from the captain that an engine has failed, but don't worry, we have three more, and we'll be an hour late. Some time later, a second announcement arrives that we've lost a second engine, but don't worry, the airplane flies fine on two engines, and we'll be two hours late. Some time later, another announcement comes; we've lost a third engine, we're okay, but we'll be three hours late.
The man turns to his traveling companion and says "great, if we lose the last one, we'll be up here all day."
One engine, not a problem. Two engines, it's a problem, but we can manage. We're diverting, landing, but we can do it. Three engines is a big problem. Four engines, we're going swimming or it's going to become a fairly short flight. Ironically, the 747 glides well for such a large airplane. There are fewer and fewer four engine airplanes, however, and the two-engine airplane is favored today.
We have multiple engines in aircraft partially for redundancy and safety, but primarily for performance. More thrust means greater performance. Today we have aircraft such as the 777 which don't use more engines, but bigger engines. If an engine is lost, there's only one left, but it's also a much bigger engine.
Losing engines isn't just a matter of losing thrust. Engines provide a lot of other things that are used in flight. We have hydraulic pumps that are used to operate flight controls, flaps, spoilers or speed brakes, landing gear, etc. We use compressed air from the engines ("bleed air") for pressurizing the airplane, heating cabin air, protecting the wings from ice in clouds, pressurizing oil and hydraulic tanks, etc. Engines have generators that supply large electrical loads that do everything from operate flight controls in some aircraft to light the cabin, power the radios, etc. On a large four engine airplane, losing an engine means losing a hydraulic system, a power source, bleed air, etc. That engine also uses oil to warm the fuel, which is important at high altitudes when fuel gets cold (and thick, and can develop ice in fuel filters and engine fuel controllers). Losing an engine affects many more things than just losing thrust.
8. That brings us to your statement on re-directing fuel. You're absolutely right. Fuel must be redirected in order to keep the amount of fuel in the wings balanced, and to ensure that the remaining engines have enough fuel. Multiple fuel tanks are used in large airplanes; they may be in the wings, in the fuselage, and sometimes even at the back of the fuselage. It's important to know where the fuel is and to manage it properly during the flight. Cross feeding, cross flowing, etc is important. With loss of an engine, fuel heating can also be important.
9. You're right; getting the landing gear lowered for landing is important, and it does provide drag which helps slow the airplane. The landing gear has airspeed limits; lowering it at too high a speed can damage some parts of the airplane, so it's important to stick to the limits. If an engine (or multiple engines) is inoperative, one may want to delay lowering the landing gear in some cases. There are other situations on short flights in heavy aircraft when one delays raising the landing gear, and lowers it early, to help cool the brakes.
10. 250 mph is usually too fast. The actual landing speed depends on weight and air temperature, runway conditions, and the elevation (or altitude) of the airport. Before beginning our descent from our cruise altitude, we do calculations to determine the proper speed for landing. We look at the weight we anticipate for landing, and along with the other factors just mentioned, calculate the speeds for extending flaps, and for actually landing. That speed also determines the amount of braking we'll need, along with the distance we need to get down and get stopped. Too fast and we will need more distance, and will have hotter brakes. Too fast and we may not get stopped. Brakes that get too hot may not work, either. There isn't one specific speed for landing, but it depends on the conditions of the flight.
If you can help in an emergency and you know what to do, you should help as much as you're able. Bear in mind that it's rare that there aren't several pilots riding on an airliner; in most all cases there are pilots riding in passenger seats, and often on a spare seat in the cockpit, as we go home or to work, and there are often private or commercially rated pilots on board, too. It would be very rare that both pilots in the cockpit are incapacitated, and there's nobody else on board who could fly the aircraft. Also bear in mind that if both pilots are incapacitated, it's unlikely the flight attendant would know...and the cockpit door is locked from inside.
Epilepsy doesn't take away from your ability to be a valuable and contributing member of society. It may affect what you can and can't do. We all have limitations. Most heros in the world go unrecognized, and they're found in every walk of life. Some of the most critical roles in the world aren't the most dramatic, but they're the most important. Deep down we'd all like to be something larger than life. I'd love to be a Navy SEAL. I've worked with them, have a great deal of admiration for them, but I won't ever be remotely anything like them, and that's okay. Some of the people I most look up to in the world are teachers. You don't need to perform a walter mitty fantasy of saving the day in an airliner to be important or valued, however, and you can and will contribute to the world by being you. I used to wish I could do something big, like most boys and young men. Something big turned out be having kids of my own, and leading a basic life; sometimes the biggest things are found in the most common elements of life. They don't make stories or movies about them, not always, but they're still some of the most critical building blocks of our daily lives. If you get the chance to save the day on an airliner and you're asked to do so, then step forward. But if you're never asked to do so, as 99.999999% of us will never be asked to do, then don't worry. You've got plenty in your life that will be just as heroic; the trick is learning to recognize it.
01-21-2016, 02:21 PM
#4
Gets Weekends Off
Joined APC: Aug 2014
Posts: 104
" ... By the way, is there anyone on board who knows how to fly a plane? Lmao ...
https://www.youtube.com/watch?v=zXpFznXb_vI
01-21-2016, 02:39 PM
#5
Gets Weekends Off
Joined APC: Aug 2014
Posts: 104
Originally Posted by JohnBurke
... It's rare that there aren't several pilots riding on an airliner; in most all cases there are pilots riding in passenger seats, and often on a spare seat in the cockpit, as we go home or to work, and there are often private or commercially rated pilots on board, too. It would be very rare that both pilots in the cockpit are incapacitated, and there's nobody else on board who could fly the aircraft.
^^^^ what he said ^^^
Excellent reply by JohnBurke.
It's admirable that you'd want to step in if needed.
Odds are, you'll probably never run into a case where not only both pilots are incapacitated and there are also no other active (or retired) commercial pilots on board, not to mention any other current (or former) military pilots or civilian general aviation pilots, any of whom would be preferable to take the controls over someone with no experience whatsoever actually piloting an airplane.
It's great that you are fascinated by aviation and understand the principles of flight. But I can't overstate how very superficial that (very) general knowledge of some of the basics is compared to what we learn as pilots. There's a lot more complexity to it that might meet the eye, as evidenced by JohnBurke's reply above. Pilots fly a complex airplane with their "head" (mentally) as much as physically. It takes practice, mentally and physically, to do it even reasonably safely.
I might understand human physiology but I don't think you'd want me to practice surgery on you unless there was no other choice!
01-21-2016, 08:46 PM
#6
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Originally Posted by JohnBurke
In an emergency, all the rules that used to apply, don't apply.
The idea that a flight attendant would ask someone to come forward and fly the airplane is a common fantasy that many people have, or have had. It's the quintisential hero fantasy, similar to saving the day in a restaurant when someone's choking, or stopping a bank robbery, or being the only person in the room who knows to cut the blue wire as the clock counts down to zero.
The idea that a flight attendant would ask someone to come forward and fly the airplane is a common fantasy that many people have, or have had. It's the quintisential hero fantasy, similar to saving the day in a restaurant when someone's choking, or stopping a bank robbery, or being the only person in the room who knows to cut the blue wire as the clock counts down to zero.
Originally Posted by JohnBurke
To address your questions, or points in order, bearing in mind that flight attendants don't yell.
Originally Posted by JohnBurke
1. Yes, nose-up, with no power change, the airplane slows down and gains altitude. Nose down, it can descend and increase speed. There's a lot more to it, of course, and there are airspeed and operating limits that mean one could stall or enter mach buffet by raising or lowering the nose at the wrong time. Doing so with the autopilot engaged may result in fighting the autopilot, which has actually lead to loss of control of the aircraft and in at least one case with a Chinese 747SP, a stall, spin, and permanent damage to the airframe. You've got the general principle, though.
Originally Posted by JohnBurke
2. Thin air makes for lesser engine performance, not better. The reason that we operate turbine aircraft at high altitudes has to do with efficiency; we get higher true airspeeds (how fast the airplane is really moving, vs. what the instruments tell us)...we go faster. The engines can be operated at higher power settings at high altitudes, and we can fly at higher true airspeeds without bumping up against aircraft limitations such as airspeed limits. Turbine engines need to operate at fast rotational speeds and higher power settings to be their most efficient (power output per gallon of fuel burned). At low altitudes, they put out so much thrust that the aircraft will go too fast, when operated at high power settings; thrust must be reduced, the engine operated at lower rotational speeds and power settings, and the engines are much less efficient. We generally try to climb high as quickly as possible, and stay there as long as possible, which allows us to go as fast as possible (within limits); this is to cover as much ground as possible for each gallon of fuel burned. It's a bit more complicated than that, of course, but you get the idea.
In an emergency, one usually won't be pressing on to the destination. Fuel economy may not be the priority. Then again, it might, depending on the circumstances.[/QUOTE]
I am just thinking of all variables. Not pressing on to a flight destination.
Originally Posted by JohnBurke
3. With a depressurization at altitude, especially a rapid depressurization, it's important to get to a lower altitude as soon as possible. More important than that is that the flight crew get on their oxygen as quickly as possible, go to the emergency 100% setting immediately, and follow emergency descent procedures. Passengers aren't provided the same kind of masks or pressure oxygen system that the pilots have, and instead receive oxygen that's not under pressure. If the depressurization occurs at a high altitude (35,000', for example), chances are that the passengers are going to pass out anyway, on the way down, even though they have oxygen. They may have 100% oxygen, but there's insufficient air pressure to get it into their blood stream as they breathe.
Generally we try to get down to 14,000 as rapidly as possible, but it depends on the terrain below, as well as where the flight is at the time. At low altitude, with a long distance to cover to get to a landing site, fuel consumption could be a big issue with something like an oceanic crossing; the flight circumstances determine the proper course of action, and it changes with the needs of the flight. You're correct, however, that generally below 10,000, supplementary oxygen isn't needed.
Generally we try to get down to 14,000 as rapidly as possible, but it depends on the terrain below, as well as where the flight is at the time. At low altitude, with a long distance to cover to get to a landing site, fuel consumption could be a big issue with something like an oceanic crossing; the flight circumstances determine the proper course of action, and it changes with the needs of the flight. You're correct, however, that generally below 10,000, supplementary oxygen isn't needed.
Originally Posted by JohnBurke
4. Commercial passenger airline aircraft have much lower structural limitations than fighter aircraft so generally speaking, one shouldn't fly inverted or attempt vertical flight (or do loops or barrel rolls). Commercial aircraft are designed to fly fast, but there are limits (and they change with altitude and flight conditions); the speed limit as the aircraft climbs to high altitudes, or descends from a high altitude is actually a moving target; it's a mach operating limit that remains a fixed value, but a changing airspeed. It's still a limit that's much lower than some tactical aircraft, so no maneuvering to avoid phantom fighter jets while doing that depressurized descent to safety.
Originally Posted by JohnBurke
5. You've got it; reduce power for landing, though if you've flown commercially, you may have noticed that sometimes power is increased during the approach to land, or shortly before landing; power is used as needed up until reaching the runway. Then it's usually brought to idle, and the airplane landed. Power may appear to increase rapidly just after landing. In this case, the power levers have been brought to idle, and sometimes the same levers, or different ones, are brought into a "reverse" range, where the engines use thrust differently in order to help slow down. In this case, power actually increases again, but the thrust from the engines is diverted to the side, or sometimes even forward, to help slow the airplane. Cars don't have that feature. Brakes are also used, just like cars. In airliners, an automatic braking feature is used, giving a setting that slows the airplane at a specific rate. This heats up the brakes. When reverse thrust is applied, the aircraft still slows at the same autobraking rate, but less brake is used, so the brakes don't get as hot.
Originally Posted by JohnBurke
6. Pull back to go up, push forward to go down, and move the control wheel, or yoke, left and right to bank the airplane. None of those will turn the airplane, though. Pitching the nose up by pulling back increases the angle between the wing and the airstream, and that angle changes the lift created by the wing as well as the line of thrust, and that in turn changes the aerodynamics and creates a climb, assuming excess thrust exists for the new condition. The opposite applies for descending.
Originally Posted by JohnBurke
Banking, which is turning the wheel left or right, doesn't actually turn the airplane. Lift acts upward when the airplane is flying level, but when the airplane is banked, some of that lift isn't acting upward, but to the side to which the airplane is banked, and it "pushes" the airplane, resulting in a turn. The steeper the bank, the tighter the turn. Much of the time, airliners are restricted to about 25 degrees of bank by autopilot limitations, passenger comfort, etc. With small amounts of turn, less bank is often used.
Originally Posted by JohnBurke
Aircraft also have rudders, which don't turn the aircraft either, but do affect the turn to some degree. In small airplanes, the rudders are used by the pilot quite a bit. In large airplanes, not nearly so much, and their function is sometimes more automatic. They can be thought of as "quality" devices that improve the condition of the turn by accounting for something called "adverse yaw." Adverse yaw is caused by the ailerons and swept wings in a jet...the ailerons are moved by the control yoke when turned left or right. It's all interconnected; one thing affects another. A bit more complicated than a car, but you've got the general idea.
Originally Posted by JohnBurke
Airplanes with multiple engines can operate on less engines, and we do spend much of our time when training with an inoperative engine. Engine failures are quite rare, especially in turbine airline aircraft, but they do happen. Airline aircraft must be able to fly and climb with an engine inoperative, and we plan every takeoff with the idea that an engine could fail at the worst possible time. We plan for a failure at a low speed when we must stop on the runway, and we calculate the distance. We also plan for failures at higher speeds on takeoff, when we must continue the takeoff with that engine failed. An engine failure on takeoff is the worst possible time to lose an engine, so we focus on that in our planning.
Originally Posted by JohnBurke
A four engine airplane such as the Boeing 747 can lose an engine and continue flying, and it flies well on one engine. Loss of a second engine, especially on the same side of the airplane (both engines on the right wing, for example) is a big problem, though the airplane does remain controllable and can be landed. In training, we do cover making a two engine approach and landing, in the 747. That's as far as we go, however, and we don't train for three engines failed, or even four engines failed. It's happened...there have been extremely rare cases in which 747's lost all four engines due to volcanic ash, but again, it's very, very rare.
Originally Posted by JohnBurke
You may have heard the old joke about the man who hears the announcement from the captain that an engine has failed, but don't worry, we have three more, and we'll be an hour late. Some time later, a second announcement arrives that we've lost a second engine, but don't worry, the airplane flies fine on two engines, and we'll be two hours late. Some time later, another announcement comes; we've lost a third engine, we're okay, but we'll be three hours late.
The man turns to his traveling companion and says "great, if we lose the last one, we'll be up here all day."
The man turns to his traveling companion and says "great, if we lose the last one, we'll be up here all day."
Originally Posted by JohnBurke
One engine, not a problem. Two engines, it's a problem, but we can manage. We're diverting, landing, but we can do it. Three engines is a big problem. Four engines, we're going swimming or it's going to become a fairly short flight. Ironically, the 747 glides well for such a large airplane. There are fewer and fewer four engine airplanes, however, and the two-engine airplane is favored today.
Originally Posted by JohnBurke
We have multiple engines in aircraft partially for redundancy and safety, but primarily for performance. More thrust means greater performance. Today we have aircraft such as the 777 which don't use more engines, but bigger engines. If an engine is lost, there's only one left, but it's also a much bigger engine.
Originally Posted by JohnBurke
Losing engines isn't just a matter of losing thrust. Engines provide a lot of other things that are used in flight. We have hydraulic pumps that are used to operate flight controls, flaps, spoilers or speed brakes, landing gear, etc. We use compressed air from the engines ("bleed air") for pressurizing the airplane, heating cabin air, protecting the wings from ice in clouds, pressurizing oil and hydraulic tanks, etc. Engines have generators that supply large electrical loads that do everything from operate flight controls in some aircraft to light the cabin, power the radios, etc. On a large four engine airplane, losing an engine means losing a hydraulic system, a power source, bleed air, etc. That engine also uses oil to warm the fuel, which is important at high altitudes when fuel gets cold (and thick, and can develop ice in fuel filters and engine fuel controllers). Losing an engine affects many more things than just losing thrust.
Originally Posted by JohnBurke
8. That brings us to your statement on re-directing fuel. You're absolutely right. Fuel must be redirected in order to keep the amount of fuel in the wings balanced, and to ensure that the remaining engines have enough fuel. Multiple fuel tanks are used in large airplanes; they may be in the wings, in the fuselage, and sometimes even at the back of the fuselage. It's important to know where the fuel is and to manage it properly during the flight. Cross feeding, cross flowing, etc is important. With loss of an engine, fuel heating can also be important.
Originally Posted by JohnBurke
9. You're right; getting the landing gear lowered for landing is important, and it does provide drag which helps slow the airplane. The landing gear has airspeed limits; lowering it at too high a speed can damage some parts of the airplane, so it's important to stick to the limits. If an engine (or multiple engines) is inoperative, one may want to delay lowering the landing gear in some cases. There are other situations on short flights in heavy aircraft when one delays raising the landing gear, and lowers it early, to help cool the brakes.
Originally Posted by JohnBurke
10. 250 mph is usually too fast. The actual landing speed depends on weight and air temperature, runway conditions, and the elevation (or altitude) of the airport. Before beginning our descent from our cruise altitude, we do calculations to determine the proper speed for landing. We look at the weight we anticipate for landing, and along with the other factors just mentioned, calculate the speeds for extending flaps, and for actually landing. That speed also determines the amount of braking we'll need, along with the distance we need to get down and get stopped. Too fast and we will need more distance, and will have hotter brakes. Too fast and we may not get stopped. Brakes that get too hot may not work, either. There isn't one specific speed for landing, but it depends on the conditions of the flight.
Originally Posted by JohnBurke
If you can help in an emergency and you know what to do, you should help as much as you're able. Bear in mind that it's rare that there aren't several pilots riding on an airliner; in most all cases there are pilots riding in passenger seats, and often on a spare seat in the cockpit, as we go home or to work, and there are often private or commercially rated pilots on board, too. It would be very rare that both pilots in the cockpit are incapacitated, and there's nobody else on board who could fly the aircraft. Also bear in mind that if both pilots are incapacitated, it's unlikely the flight attendant would know...and the cockpit door is locked from inside.
Originally Posted by JohnBurke
Epilepsy doesn't take away from your ability to be a valuable and contributing member of society. It may affect what you can and can't do. We all have limitations. Most heros in the world go unrecognized, and they're found in every walk of life. Some of the most critical roles in the world aren't the most dramatic, but they're the most important. Deep down we'd all like to be something larger than life. I'd love to be a Navy SEAL. I've worked with them, have a great deal of admiration for them, but I won't ever be remotely anything like them, and that's okay. Some of the people I most look up to in the world are teachers. You don't need to perform a walter mitty fantasy of saving the day in an airliner to be important or valued, however, and you can and will contribute to the world by being you. I used to wish I could do something big, like most boys and young men. Something big turned out be having kids of my own, and leading a basic life; sometimes the biggest things are found in the most common elements of life. They don't make stories or movies about them, not always, but they're still some of the most critical building blocks of our daily lives. If you get the chance to save the day on an airliner and you're asked to do so, then step forward. But if you're never asked to do so, as 99.999999% of us will never be asked to do, then don't worry. You've got plenty in your life that will be just as heroic; the trick is learning to recognize it.
In addition to my interest in aviation(and despite my epilepsy). I know martial arts, how to play the drums, and I can ride my (road)racing bike in 40mph traffic.
Last edited by Chris516; 01-21-2016 at 09:06 PM.
01-21-2016, 08:57 PM
#7
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Joined APC: Jan 2016
Posts: 10
Originally Posted by MaxThrustPower
" ... By the way, is there anyone on board who knows how to fly a plane? https://www.youtube.com/watch?v=zXpFznXb_vI
[QUOTE=MaxThrustPower;2052410]
^^^^ what he said ^^^
Excellent reply by JohnBurke.
Originally Posted by MaxThrustPower
It's admirable that you'd want to step in if needed.
Originally Posted by MaxThrustPower
Odds are, you'll probably never run into a case where not only both pilots are incapacitated and there are also no other active (or retired) commercial pilots on board, not to mention any other current (or former) military pilots or civilian general aviation pilots, any of whom would be preferable to take the controls over someone with no experience whatsoever actually piloting an airplane.
Originally Posted by MaxThrustPower
It's great that you are fascinated by aviation and understand the principles of flight. But I can't overstate how very superficial that (very) general knowledge of some of the basics is compared to what we learn as pilots. There's a lot more complexity to it that might meet the eye, as evidenced by JohnBurke's reply above. Pilots fly a complex airplane with their "head" (mentally) as much as physically. It takes practice, mentally and physically, to do it even reasonably safely.
Originally Posted by MaxThrustPower
I might understand human physiology but I don't think you'd want me to practice surgery on you unless there was no other choice!
01-21-2016, 10:42 PM
#8
Disinterested Third Party
Joined APC: Jun 2012
Posts: 5,347
Originally Posted by Chris516
I know there is more to it. Because, If the speed is too slow in the climb. The plane, in essence. Will not be able to counter the earth's gravitational pull. Yes, I know about autopilot. Once altitude has been reached, is when the autopilot is turned on. Wasn't the case of the China Airlines 747SP. Where the Captain had left the cockpit, then the First Officer started having a problem almost immediately. Didn't the First Officer think that putting the plane in a nose-up attitude, was how to gain altitude. When he was actually slowing the plane down, creating the stall. But when the Captain came back. Instead of correcting the First Officer's mistake. The Captain made it worse. By copying the First Officer's mistake.
China Airlines 006 was a classic case of the crew being out of the loop while the aircraft was in automation, and then misuse of the automation. With loss of power on the #4 powerplant, a series of errors largely due to failure to manage the autopilot and autothrottles lead to a control departure.
China Airlines B747SP Loss of Power and Inflight Upset
01-22-2016, 04:35 AM
#9
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Posts: 10
Originally Posted by JohnBurke
No.
China Airlines 006 was a classic case of the crew being out of the loop while the aircraft was in automation, and then misuse of the automation. With loss of power on the #4 powerplant, a series of errors largely due to failure to manage the autopilot and autothrottles lead to a control departure.
China Airlines B747SP Loss of Power and Inflight Upset
China Airlines 006 was a classic case of the crew being out of the loop while the aircraft was in automation, and then misuse of the automation. With loss of power on the #4 powerplant, a series of errors largely due to failure to manage the autopilot and autothrottles lead to a control departure.
China Airlines B747SP Loss of Power and Inflight Upset
01-22-2016, 08:46 AM
#10
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Joined APC: Oct 2014
Posts: 249
No, just stay seated because either way you're a goner.
