Why are fuel tanks located in wings?
up vote
10
down vote
favorite
Passenger aircraft have fuel tanks in the wings. Why?
What are the advantages and disadvantages of this location ?
examples of disadvantages I would suspect:
- added weight increases the structural load applied to the wings
- different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
- higher risk of catastrophic damage to wings in case of in-flight fuel ignition
- higher risk of fire when lightning strikes a wing
aircraft-design wing fuel-tanks aircraft-structures fuel-systems
add a comment |
up vote
10
down vote
favorite
Passenger aircraft have fuel tanks in the wings. Why?
What are the advantages and disadvantages of this location ?
examples of disadvantages I would suspect:
- added weight increases the structural load applied to the wings
- different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
- higher risk of catastrophic damage to wings in case of in-flight fuel ignition
- higher risk of fire when lightning strikes a wing
aircraft-design wing fuel-tanks aircraft-structures fuel-systems
13
Keeping fuel in the wings actually helps to maintain their structural integrity, see aviation.stackexchange.com/questions/42613/…
– DeepSpace
20 hours ago
2
On the ground, the aircraft rests on the wheels. In flight, it rests on the wings - so weight in the wings reduces structural loading, not increases it.
– Therac
13 hours ago
@Therac: Following your explanation, I would see that it does not add structural load? But how would weight "reduce" structural load?
– summerrain
13 hours ago
@summerrain By balancing out the fuselage, which is a big central load. See A340 vs A330. Of course, this implies total weight is equal or within some limit.
– Therac
12 hours ago
add a comment |
up vote
10
down vote
favorite
up vote
10
down vote
favorite
Passenger aircraft have fuel tanks in the wings. Why?
What are the advantages and disadvantages of this location ?
examples of disadvantages I would suspect:
- added weight increases the structural load applied to the wings
- different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
- higher risk of catastrophic damage to wings in case of in-flight fuel ignition
- higher risk of fire when lightning strikes a wing
aircraft-design wing fuel-tanks aircraft-structures fuel-systems
Passenger aircraft have fuel tanks in the wings. Why?
What are the advantages and disadvantages of this location ?
examples of disadvantages I would suspect:
- added weight increases the structural load applied to the wings
- different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
- higher risk of catastrophic damage to wings in case of in-flight fuel ignition
- higher risk of fire when lightning strikes a wing
aircraft-design wing fuel-tanks aircraft-structures fuel-systems
aircraft-design wing fuel-tanks aircraft-structures fuel-systems
edited 13 hours ago
asked 22 hours ago
summerrain
613415
613415
13
Keeping fuel in the wings actually helps to maintain their structural integrity, see aviation.stackexchange.com/questions/42613/…
– DeepSpace
20 hours ago
2
On the ground, the aircraft rests on the wheels. In flight, it rests on the wings - so weight in the wings reduces structural loading, not increases it.
– Therac
13 hours ago
@Therac: Following your explanation, I would see that it does not add structural load? But how would weight "reduce" structural load?
– summerrain
13 hours ago
@summerrain By balancing out the fuselage, which is a big central load. See A340 vs A330. Of course, this implies total weight is equal or within some limit.
– Therac
12 hours ago
add a comment |
13
Keeping fuel in the wings actually helps to maintain their structural integrity, see aviation.stackexchange.com/questions/42613/…
– DeepSpace
20 hours ago
2
On the ground, the aircraft rests on the wheels. In flight, it rests on the wings - so weight in the wings reduces structural loading, not increases it.
– Therac
13 hours ago
@Therac: Following your explanation, I would see that it does not add structural load? But how would weight "reduce" structural load?
– summerrain
13 hours ago
@summerrain By balancing out the fuselage, which is a big central load. See A340 vs A330. Of course, this implies total weight is equal or within some limit.
– Therac
12 hours ago
13
13
Keeping fuel in the wings actually helps to maintain their structural integrity, see aviation.stackexchange.com/questions/42613/…
– DeepSpace
20 hours ago
Keeping fuel in the wings actually helps to maintain their structural integrity, see aviation.stackexchange.com/questions/42613/…
– DeepSpace
20 hours ago
2
2
On the ground, the aircraft rests on the wheels. In flight, it rests on the wings - so weight in the wings reduces structural loading, not increases it.
– Therac
13 hours ago
On the ground, the aircraft rests on the wheels. In flight, it rests on the wings - so weight in the wings reduces structural loading, not increases it.
– Therac
13 hours ago
@Therac: Following your explanation, I would see that it does not add structural load? But how would weight "reduce" structural load?
– summerrain
13 hours ago
@Therac: Following your explanation, I would see that it does not add structural load? But how would weight "reduce" structural load?
– summerrain
13 hours ago
@summerrain By balancing out the fuselage, which is a big central load. See A340 vs A330. Of course, this implies total weight is equal or within some limit.
– Therac
12 hours ago
@summerrain By balancing out the fuselage, which is a big central load. See A340 vs A330. Of course, this implies total weight is equal or within some limit.
– Therac
12 hours ago
add a comment |
6 Answers
6
active
oldest
votes
up vote
38
down vote
Several advantages:
Wing structures are hollow and voluminous in order to provide structural rigidity against flutter and carry flight loads. This provides the space needed to store fuel.
On a conventional aircraft, placing fuel tanks in the wings places the fuel mass very close to, or on, the center of lift. This dramatically reduces Cg shift during flight and reduces the size and weight of the tailplane to maintain stable flight.
In the event of a crash landing, having the fuel in the wings keeps it away from the cabin and the occupants, reducing risks of cabin fires.
The weight of the fuel reduces the loading moment on the wing roots, reducing the weight of the structure needed to support the aircraft during flight.
add a comment |
up vote
13
down vote
added weight increases the structural load applied to the wings
different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
As a result of the effects of lift (and the deceasing need for it as the plane lightens) the reverse is actually true see here
higher risk of catastrophic damage to wings in case of in-flight fuel ignition
As opposed to higher risk of catastrophic damage to the cabin in the case of in-flight fuel ignition?
Assuming a non-explosive ignition having the fuel in the wings means you can take action to dump the fuel. If you have a fire begin in the main fuselage however you've got a higher chance of the fire incapacitating the crew before they can take steps. Or damage occuring to the avionics, the pressure cabin etc.
maybe higher risk of fire when lightning strikes a wing ?
Wing tips are one of the locations on a plane that is more prone to lightning strikes - and the potential for fuel fires is there but steps are taken to counter this and in the vast majority of cases lightning does very little damage
add a comment |
up vote
9
down vote
Quite simply: there's a lot of empty space in those wings, and there's a lot of empty space needed for fuel.
Creating space elsewhere for fuel would make the entire aircraft larger and heavier, so makes little sense.
And it's not just the wings, many aircraft carry fuel in the vertical stabiliser as well.
35
In other words: Why are fuel tanks located in the wings? Because the passengers wouldn't fit in there. :)
– Tanner Swett
18 hours ago
20
@TannerSwett Don't give them any ideas...
– pipe
16 hours ago
3
@pipe en.wikipedia.org/wiki/Junkers_G.38 ?
– DeepSpace
14 hours ago
@TannerSwett hmm, Ryanair wants to talk with you about that idea.
– jwenting
2 hours ago
add a comment |
up vote
9
down vote
I see what you're saying, but there's something you're overlooking in your logic. You're looking at an airplane sitting on the ground, where the wheels are under the fuselage and the wings are deadweight that creates strain on the structure.
Think about one in flight. Now all the lift is coming from the wings, imagine the airplane suspended by a couple dozen (billion) cables spread around the wing surfaces. Now the fuselage is deadweight and the strain in the structure is from carrying the fuselage.
So when you add weight to the wings evenly, it adds practically zero structural load for the wings. What's being lifted is inside the source of the lift. So from a structural load perspective, it's a wash: it doesn't matter.
Whereas if you add more tanks in the fuselage, that's fine on the ground, but it adds huge stresses to the wings inflight, effectively reducing practical cargo capacity.
The strain on wings from sitting on the ground is much less worrisome to designers than the strains inflight.
See also "Zero Fuel Weight".
Exactly what I was thinking, but you said it much better!
– Michael Hall
9 hours ago
add a comment |
up vote
3
down vote
- added weight increases the structural load applied to the wings
Only when the plane's on the ground. When it's in the air, it decreases the load on the wings because their lift balances the weight.
- different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
At the rate of one cycle per flight. And the wings already go through a stress cycle once per flight (flexed down when the plane's on the ground and up when it's in the air).
- higher risk of catastrophic damage to wings in case of in-flight fuel ignition
The fuel tanks catching fire in flight is catastrophic wherever you put them.
- higher risk of fire when lightning strikes a wing
When did that last happen? Wikipedia's list of plane crashes suggests LANSA flight 508 in 1971. Such incidents are so rare because fuel tanks have been fitted with inerting systems as recommended after the crash of Pan Am flight 214 in 1963.
add a comment |
up vote
3
down vote
Along with the other answers, I'll point out the cases where an aircraft fuel tank exploded, the center tank, which is in the fuselage, was implicated. There are two reasons:
First, a fuselage tank is located lower than the engines and requires pumps to raise the fuel. Electrical pump failures have caused explosions. This also means that a pump failure results in unusable fuel, whereas wing tanks can naturally feed the engines via gravity.
Second, fuselage tanks are closer to sources of heat. This was a cause of the TWA flight 800 accident, where heat from nearby air conditioning equipment lead to a flammable vapor in the fuel tanks. In contrast, wing tanks are naturally cooled by airflow and are less susceptible to forming such explosive vapors.
add a comment |
6 Answers
6
active
oldest
votes
6 Answers
6
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
38
down vote
Several advantages:
Wing structures are hollow and voluminous in order to provide structural rigidity against flutter and carry flight loads. This provides the space needed to store fuel.
On a conventional aircraft, placing fuel tanks in the wings places the fuel mass very close to, or on, the center of lift. This dramatically reduces Cg shift during flight and reduces the size and weight of the tailplane to maintain stable flight.
In the event of a crash landing, having the fuel in the wings keeps it away from the cabin and the occupants, reducing risks of cabin fires.
The weight of the fuel reduces the loading moment on the wing roots, reducing the weight of the structure needed to support the aircraft during flight.
add a comment |
up vote
38
down vote
Several advantages:
Wing structures are hollow and voluminous in order to provide structural rigidity against flutter and carry flight loads. This provides the space needed to store fuel.
On a conventional aircraft, placing fuel tanks in the wings places the fuel mass very close to, or on, the center of lift. This dramatically reduces Cg shift during flight and reduces the size and weight of the tailplane to maintain stable flight.
In the event of a crash landing, having the fuel in the wings keeps it away from the cabin and the occupants, reducing risks of cabin fires.
The weight of the fuel reduces the loading moment on the wing roots, reducing the weight of the structure needed to support the aircraft during flight.
add a comment |
up vote
38
down vote
up vote
38
down vote
Several advantages:
Wing structures are hollow and voluminous in order to provide structural rigidity against flutter and carry flight loads. This provides the space needed to store fuel.
On a conventional aircraft, placing fuel tanks in the wings places the fuel mass very close to, or on, the center of lift. This dramatically reduces Cg shift during flight and reduces the size and weight of the tailplane to maintain stable flight.
In the event of a crash landing, having the fuel in the wings keeps it away from the cabin and the occupants, reducing risks of cabin fires.
The weight of the fuel reduces the loading moment on the wing roots, reducing the weight of the structure needed to support the aircraft during flight.
Several advantages:
Wing structures are hollow and voluminous in order to provide structural rigidity against flutter and carry flight loads. This provides the space needed to store fuel.
On a conventional aircraft, placing fuel tanks in the wings places the fuel mass very close to, or on, the center of lift. This dramatically reduces Cg shift during flight and reduces the size and weight of the tailplane to maintain stable flight.
In the event of a crash landing, having the fuel in the wings keeps it away from the cabin and the occupants, reducing risks of cabin fires.
The weight of the fuel reduces the loading moment on the wing roots, reducing the weight of the structure needed to support the aircraft during flight.
answered 17 hours ago
Carlo Felicione
39.6k272147
39.6k272147
add a comment |
add a comment |
up vote
13
down vote
added weight increases the structural load applied to the wings
different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
As a result of the effects of lift (and the deceasing need for it as the plane lightens) the reverse is actually true see here
higher risk of catastrophic damage to wings in case of in-flight fuel ignition
As opposed to higher risk of catastrophic damage to the cabin in the case of in-flight fuel ignition?
Assuming a non-explosive ignition having the fuel in the wings means you can take action to dump the fuel. If you have a fire begin in the main fuselage however you've got a higher chance of the fire incapacitating the crew before they can take steps. Or damage occuring to the avionics, the pressure cabin etc.
maybe higher risk of fire when lightning strikes a wing ?
Wing tips are one of the locations on a plane that is more prone to lightning strikes - and the potential for fuel fires is there but steps are taken to counter this and in the vast majority of cases lightning does very little damage
add a comment |
up vote
13
down vote
added weight increases the structural load applied to the wings
different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
As a result of the effects of lift (and the deceasing need for it as the plane lightens) the reverse is actually true see here
higher risk of catastrophic damage to wings in case of in-flight fuel ignition
As opposed to higher risk of catastrophic damage to the cabin in the case of in-flight fuel ignition?
Assuming a non-explosive ignition having the fuel in the wings means you can take action to dump the fuel. If you have a fire begin in the main fuselage however you've got a higher chance of the fire incapacitating the crew before they can take steps. Or damage occuring to the avionics, the pressure cabin etc.
maybe higher risk of fire when lightning strikes a wing ?
Wing tips are one of the locations on a plane that is more prone to lightning strikes - and the potential for fuel fires is there but steps are taken to counter this and in the vast majority of cases lightning does very little damage
add a comment |
up vote
13
down vote
up vote
13
down vote
added weight increases the structural load applied to the wings
different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
As a result of the effects of lift (and the deceasing need for it as the plane lightens) the reverse is actually true see here
higher risk of catastrophic damage to wings in case of in-flight fuel ignition
As opposed to higher risk of catastrophic damage to the cabin in the case of in-flight fuel ignition?
Assuming a non-explosive ignition having the fuel in the wings means you can take action to dump the fuel. If you have a fire begin in the main fuselage however you've got a higher chance of the fire incapacitating the crew before they can take steps. Or damage occuring to the avionics, the pressure cabin etc.
maybe higher risk of fire when lightning strikes a wing ?
Wing tips are one of the locations on a plane that is more prone to lightning strikes - and the potential for fuel fires is there but steps are taken to counter this and in the vast majority of cases lightning does very little damage
added weight increases the structural load applied to the wings
different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
As a result of the effects of lift (and the deceasing need for it as the plane lightens) the reverse is actually true see here
higher risk of catastrophic damage to wings in case of in-flight fuel ignition
As opposed to higher risk of catastrophic damage to the cabin in the case of in-flight fuel ignition?
Assuming a non-explosive ignition having the fuel in the wings means you can take action to dump the fuel. If you have a fire begin in the main fuselage however you've got a higher chance of the fire incapacitating the crew before they can take steps. Or damage occuring to the avionics, the pressure cabin etc.
maybe higher risk of fire when lightning strikes a wing ?
Wing tips are one of the locations on a plane that is more prone to lightning strikes - and the potential for fuel fires is there but steps are taken to counter this and in the vast majority of cases lightning does very little damage
answered 19 hours ago
motosubatsu
3337
3337
add a comment |
add a comment |
up vote
9
down vote
Quite simply: there's a lot of empty space in those wings, and there's a lot of empty space needed for fuel.
Creating space elsewhere for fuel would make the entire aircraft larger and heavier, so makes little sense.
And it's not just the wings, many aircraft carry fuel in the vertical stabiliser as well.
35
In other words: Why are fuel tanks located in the wings? Because the passengers wouldn't fit in there. :)
– Tanner Swett
18 hours ago
20
@TannerSwett Don't give them any ideas...
– pipe
16 hours ago
3
@pipe en.wikipedia.org/wiki/Junkers_G.38 ?
– DeepSpace
14 hours ago
@TannerSwett hmm, Ryanair wants to talk with you about that idea.
– jwenting
2 hours ago
add a comment |
up vote
9
down vote
Quite simply: there's a lot of empty space in those wings, and there's a lot of empty space needed for fuel.
Creating space elsewhere for fuel would make the entire aircraft larger and heavier, so makes little sense.
And it's not just the wings, many aircraft carry fuel in the vertical stabiliser as well.
35
In other words: Why are fuel tanks located in the wings? Because the passengers wouldn't fit in there. :)
– Tanner Swett
18 hours ago
20
@TannerSwett Don't give them any ideas...
– pipe
16 hours ago
3
@pipe en.wikipedia.org/wiki/Junkers_G.38 ?
– DeepSpace
14 hours ago
@TannerSwett hmm, Ryanair wants to talk with you about that idea.
– jwenting
2 hours ago
add a comment |
up vote
9
down vote
up vote
9
down vote
Quite simply: there's a lot of empty space in those wings, and there's a lot of empty space needed for fuel.
Creating space elsewhere for fuel would make the entire aircraft larger and heavier, so makes little sense.
And it's not just the wings, many aircraft carry fuel in the vertical stabiliser as well.
Quite simply: there's a lot of empty space in those wings, and there's a lot of empty space needed for fuel.
Creating space elsewhere for fuel would make the entire aircraft larger and heavier, so makes little sense.
And it's not just the wings, many aircraft carry fuel in the vertical stabiliser as well.
answered 21 hours ago
jwenting
10.9k12743
10.9k12743
35
In other words: Why are fuel tanks located in the wings? Because the passengers wouldn't fit in there. :)
– Tanner Swett
18 hours ago
20
@TannerSwett Don't give them any ideas...
– pipe
16 hours ago
3
@pipe en.wikipedia.org/wiki/Junkers_G.38 ?
– DeepSpace
14 hours ago
@TannerSwett hmm, Ryanair wants to talk with you about that idea.
– jwenting
2 hours ago
add a comment |
35
In other words: Why are fuel tanks located in the wings? Because the passengers wouldn't fit in there. :)
– Tanner Swett
18 hours ago
20
@TannerSwett Don't give them any ideas...
– pipe
16 hours ago
3
@pipe en.wikipedia.org/wiki/Junkers_G.38 ?
– DeepSpace
14 hours ago
@TannerSwett hmm, Ryanair wants to talk with you about that idea.
– jwenting
2 hours ago
35
35
In other words: Why are fuel tanks located in the wings? Because the passengers wouldn't fit in there. :)
– Tanner Swett
18 hours ago
In other words: Why are fuel tanks located in the wings? Because the passengers wouldn't fit in there. :)
– Tanner Swett
18 hours ago
20
20
@TannerSwett Don't give them any ideas...
– pipe
16 hours ago
@TannerSwett Don't give them any ideas...
– pipe
16 hours ago
3
3
@pipe en.wikipedia.org/wiki/Junkers_G.38 ?
– DeepSpace
14 hours ago
@pipe en.wikipedia.org/wiki/Junkers_G.38 ?
– DeepSpace
14 hours ago
@TannerSwett hmm, Ryanair wants to talk with you about that idea.
– jwenting
2 hours ago
@TannerSwett hmm, Ryanair wants to talk with you about that idea.
– jwenting
2 hours ago
add a comment |
up vote
9
down vote
I see what you're saying, but there's something you're overlooking in your logic. You're looking at an airplane sitting on the ground, where the wheels are under the fuselage and the wings are deadweight that creates strain on the structure.
Think about one in flight. Now all the lift is coming from the wings, imagine the airplane suspended by a couple dozen (billion) cables spread around the wing surfaces. Now the fuselage is deadweight and the strain in the structure is from carrying the fuselage.
So when you add weight to the wings evenly, it adds practically zero structural load for the wings. What's being lifted is inside the source of the lift. So from a structural load perspective, it's a wash: it doesn't matter.
Whereas if you add more tanks in the fuselage, that's fine on the ground, but it adds huge stresses to the wings inflight, effectively reducing practical cargo capacity.
The strain on wings from sitting on the ground is much less worrisome to designers than the strains inflight.
See also "Zero Fuel Weight".
Exactly what I was thinking, but you said it much better!
– Michael Hall
9 hours ago
add a comment |
up vote
9
down vote
I see what you're saying, but there's something you're overlooking in your logic. You're looking at an airplane sitting on the ground, where the wheels are under the fuselage and the wings are deadweight that creates strain on the structure.
Think about one in flight. Now all the lift is coming from the wings, imagine the airplane suspended by a couple dozen (billion) cables spread around the wing surfaces. Now the fuselage is deadweight and the strain in the structure is from carrying the fuselage.
So when you add weight to the wings evenly, it adds practically zero structural load for the wings. What's being lifted is inside the source of the lift. So from a structural load perspective, it's a wash: it doesn't matter.
Whereas if you add more tanks in the fuselage, that's fine on the ground, but it adds huge stresses to the wings inflight, effectively reducing practical cargo capacity.
The strain on wings from sitting on the ground is much less worrisome to designers than the strains inflight.
See also "Zero Fuel Weight".
Exactly what I was thinking, but you said it much better!
– Michael Hall
9 hours ago
add a comment |
up vote
9
down vote
up vote
9
down vote
I see what you're saying, but there's something you're overlooking in your logic. You're looking at an airplane sitting on the ground, where the wheels are under the fuselage and the wings are deadweight that creates strain on the structure.
Think about one in flight. Now all the lift is coming from the wings, imagine the airplane suspended by a couple dozen (billion) cables spread around the wing surfaces. Now the fuselage is deadweight and the strain in the structure is from carrying the fuselage.
So when you add weight to the wings evenly, it adds practically zero structural load for the wings. What's being lifted is inside the source of the lift. So from a structural load perspective, it's a wash: it doesn't matter.
Whereas if you add more tanks in the fuselage, that's fine on the ground, but it adds huge stresses to the wings inflight, effectively reducing practical cargo capacity.
The strain on wings from sitting on the ground is much less worrisome to designers than the strains inflight.
See also "Zero Fuel Weight".
I see what you're saying, but there's something you're overlooking in your logic. You're looking at an airplane sitting on the ground, where the wheels are under the fuselage and the wings are deadweight that creates strain on the structure.
Think about one in flight. Now all the lift is coming from the wings, imagine the airplane suspended by a couple dozen (billion) cables spread around the wing surfaces. Now the fuselage is deadweight and the strain in the structure is from carrying the fuselage.
So when you add weight to the wings evenly, it adds practically zero structural load for the wings. What's being lifted is inside the source of the lift. So from a structural load perspective, it's a wash: it doesn't matter.
Whereas if you add more tanks in the fuselage, that's fine on the ground, but it adds huge stresses to the wings inflight, effectively reducing practical cargo capacity.
The strain on wings from sitting on the ground is much less worrisome to designers than the strains inflight.
See also "Zero Fuel Weight".
edited 12 hours ago
answered 13 hours ago
Harper
2,105515
2,105515
Exactly what I was thinking, but you said it much better!
– Michael Hall
9 hours ago
add a comment |
Exactly what I was thinking, but you said it much better!
– Michael Hall
9 hours ago
Exactly what I was thinking, but you said it much better!
– Michael Hall
9 hours ago
Exactly what I was thinking, but you said it much better!
– Michael Hall
9 hours ago
add a comment |
up vote
3
down vote
- added weight increases the structural load applied to the wings
Only when the plane's on the ground. When it's in the air, it decreases the load on the wings because their lift balances the weight.
- different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
At the rate of one cycle per flight. And the wings already go through a stress cycle once per flight (flexed down when the plane's on the ground and up when it's in the air).
- higher risk of catastrophic damage to wings in case of in-flight fuel ignition
The fuel tanks catching fire in flight is catastrophic wherever you put them.
- higher risk of fire when lightning strikes a wing
When did that last happen? Wikipedia's list of plane crashes suggests LANSA flight 508 in 1971. Such incidents are so rare because fuel tanks have been fitted with inerting systems as recommended after the crash of Pan Am flight 214 in 1963.
add a comment |
up vote
3
down vote
- added weight increases the structural load applied to the wings
Only when the plane's on the ground. When it's in the air, it decreases the load on the wings because their lift balances the weight.
- different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
At the rate of one cycle per flight. And the wings already go through a stress cycle once per flight (flexed down when the plane's on the ground and up when it's in the air).
- higher risk of catastrophic damage to wings in case of in-flight fuel ignition
The fuel tanks catching fire in flight is catastrophic wherever you put them.
- higher risk of fire when lightning strikes a wing
When did that last happen? Wikipedia's list of plane crashes suggests LANSA flight 508 in 1971. Such incidents are so rare because fuel tanks have been fitted with inerting systems as recommended after the crash of Pan Am flight 214 in 1963.
add a comment |
up vote
3
down vote
up vote
3
down vote
- added weight increases the structural load applied to the wings
Only when the plane's on the ground. When it's in the air, it decreases the load on the wings because their lift balances the weight.
- different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
At the rate of one cycle per flight. And the wings already go through a stress cycle once per flight (flexed down when the plane's on the ground and up when it's in the air).
- higher risk of catastrophic damage to wings in case of in-flight fuel ignition
The fuel tanks catching fire in flight is catastrophic wherever you put them.
- higher risk of fire when lightning strikes a wing
When did that last happen? Wikipedia's list of plane crashes suggests LANSA flight 508 in 1971. Such incidents are so rare because fuel tanks have been fitted with inerting systems as recommended after the crash of Pan Am flight 214 in 1963.
- added weight increases the structural load applied to the wings
Only when the plane's on the ground. When it's in the air, it decreases the load on the wings because their lift balances the weight.
- different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span
At the rate of one cycle per flight. And the wings already go through a stress cycle once per flight (flexed down when the plane's on the ground and up when it's in the air).
- higher risk of catastrophic damage to wings in case of in-flight fuel ignition
The fuel tanks catching fire in flight is catastrophic wherever you put them.
- higher risk of fire when lightning strikes a wing
When did that last happen? Wikipedia's list of plane crashes suggests LANSA flight 508 in 1971. Such incidents are so rare because fuel tanks have been fitted with inerting systems as recommended after the crash of Pan Am flight 214 in 1963.
answered 11 hours ago
David Richerby
9,53833477
9,53833477
add a comment |
add a comment |
up vote
3
down vote
Along with the other answers, I'll point out the cases where an aircraft fuel tank exploded, the center tank, which is in the fuselage, was implicated. There are two reasons:
First, a fuselage tank is located lower than the engines and requires pumps to raise the fuel. Electrical pump failures have caused explosions. This also means that a pump failure results in unusable fuel, whereas wing tanks can naturally feed the engines via gravity.
Second, fuselage tanks are closer to sources of heat. This was a cause of the TWA flight 800 accident, where heat from nearby air conditioning equipment lead to a flammable vapor in the fuel tanks. In contrast, wing tanks are naturally cooled by airflow and are less susceptible to forming such explosive vapors.
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Along with the other answers, I'll point out the cases where an aircraft fuel tank exploded, the center tank, which is in the fuselage, was implicated. There are two reasons:
First, a fuselage tank is located lower than the engines and requires pumps to raise the fuel. Electrical pump failures have caused explosions. This also means that a pump failure results in unusable fuel, whereas wing tanks can naturally feed the engines via gravity.
Second, fuselage tanks are closer to sources of heat. This was a cause of the TWA flight 800 accident, where heat from nearby air conditioning equipment lead to a flammable vapor in the fuel tanks. In contrast, wing tanks are naturally cooled by airflow and are less susceptible to forming such explosive vapors.
add a comment |
up vote
3
down vote
up vote
3
down vote
Along with the other answers, I'll point out the cases where an aircraft fuel tank exploded, the center tank, which is in the fuselage, was implicated. There are two reasons:
First, a fuselage tank is located lower than the engines and requires pumps to raise the fuel. Electrical pump failures have caused explosions. This also means that a pump failure results in unusable fuel, whereas wing tanks can naturally feed the engines via gravity.
Second, fuselage tanks are closer to sources of heat. This was a cause of the TWA flight 800 accident, where heat from nearby air conditioning equipment lead to a flammable vapor in the fuel tanks. In contrast, wing tanks are naturally cooled by airflow and are less susceptible to forming such explosive vapors.
Along with the other answers, I'll point out the cases where an aircraft fuel tank exploded, the center tank, which is in the fuselage, was implicated. There are two reasons:
First, a fuselage tank is located lower than the engines and requires pumps to raise the fuel. Electrical pump failures have caused explosions. This also means that a pump failure results in unusable fuel, whereas wing tanks can naturally feed the engines via gravity.
Second, fuselage tanks are closer to sources of heat. This was a cause of the TWA flight 800 accident, where heat from nearby air conditioning equipment lead to a flammable vapor in the fuel tanks. In contrast, wing tanks are naturally cooled by airflow and are less susceptible to forming such explosive vapors.
answered 8 hours ago
user71659
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2,244617
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13
Keeping fuel in the wings actually helps to maintain their structural integrity, see aviation.stackexchange.com/questions/42613/…
– DeepSpace
20 hours ago
2
On the ground, the aircraft rests on the wheels. In flight, it rests on the wings - so weight in the wings reduces structural loading, not increases it.
– Therac
13 hours ago
@Therac: Following your explanation, I would see that it does not add structural load? But how would weight "reduce" structural load?
– summerrain
13 hours ago
@summerrain By balancing out the fuselage, which is a big central load. See A340 vs A330. Of course, this implies total weight is equal or within some limit.
– Therac
12 hours ago