Why can't wing-mounted spoilers be used to steepen approaches?
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In a comment on this answer to my previous question about tail-mounted airbrakes (lack of), @JohnK states:
You won't see flight spoilers (speed brakes) being used to steepen approaches. You have to be 10kt above Vref to extend them on a CRJ900 and you shouldn't be that hot in the first place, and you aren't allowed to use them at all below 300 ft.
Why do you have to be going abnormally fast to slow down with the spoilers, and why can't they be used at low altitude (especially given that, just like with airbrakes, it would seem to me like spoiler extension would be a safer method of slowing down than pulling the throttle all the way back would be, since, should a go-around become necessary, the spoilers can retract a lot more quickly than the engines can spool up from idle to TOGA)?
approach spoilers
asked 3 hours ago
SeanSean
5,98232875
$endgroup$
add a comment |
$begingroup$
In a comment on this answer to my previous question about tail-mounted airbrakes (lack of), @JohnK states:
You won't see flight spoilers (speed brakes) being used to steepen approaches. You have to be 10kt above Vref to extend them on a CRJ900 and you shouldn't be that hot in the first place, and you aren't allowed to use them at all below 300 ft.
Why do you have to be going abnormally fast to slow down with the spoilers, and why can't they be used at low altitude (especially given that, just like with airbrakes, it would seem to me like spoiler extension would be a safer method of slowing down than pulling the throttle all the way back would be, since, should a go-around become necessary, the spoilers can retract a lot more quickly than the engines can spool up from idle to TOGA)?
approach spoilers
asked 3 hours ago
SeanSean
5,98232875
$endgroup$
$begingroup$
Engines are never at idle on approach until the landing flare for that exact reason.
$endgroup$
– Ben
1 hour ago
add a comment |
$begingroup$
In a comment on this answer to my previous question about tail-mounted airbrakes (lack of), @JohnK states:
You won't see flight spoilers (speed brakes) being used to steepen approaches. You have to be 10kt above Vref to extend them on a CRJ900 and you shouldn't be that hot in the first place, and you aren't allowed to use them at all below 300 ft.
Why do you have to be going abnormally fast to slow down with the spoilers, and why can't they be used at low altitude (especially given that, just like with airbrakes, it would seem to me like spoiler extension would be a safer method of slowing down than pulling the throttle all the way back would be, since, should a go-around become necessary, the spoilers can retract a lot more quickly than the engines can spool up from idle to TOGA)?
approach spoilers
asked 3 hours ago
SeanSean
5,98232875
$endgroup$
In a comment on this answer to my previous question about tail-mounted airbrakes (lack of), @JohnK states:
You won't see flight spoilers (speed brakes) being used to steepen approaches. You have to be 10kt above Vref to extend them on a CRJ900 and you shouldn't be that hot in the first place, and you aren't allowed to use them at all below 300 ft.
Why do you have to be going abnormally fast to slow down with the spoilers, and why can't they be used at low altitude (especially given that, just like with airbrakes, it would seem to me like spoiler extension would be a safer method of slowing down than pulling the throttle all the way back would be, since, should a go-around become necessary, the spoilers can retract a lot more quickly than the engines can spool up from idle to TOGA)?
approach spoilers
approach spoilers
asked 3 hours ago
SeanSean
5,98232875
asked 3 hours ago
SeanSean
5,98232875
asked 3 hours ago
SeanSean
5,98232875
asked 3 hours ago
SeanSean
5,98232875
asked 3 hours ago
SeanSean
5,98232875
5,98232875
$begingroup$
Engines are never at idle on approach until the landing flare for that exact reason.
$endgroup$
– Ben
1 hour ago
add a comment |
$begingroup$
Engines are never at idle on approach until the landing flare for that exact reason.
$endgroup$
– Ben
1 hour ago
$begingroup$
Engines are never at idle on approach until the landing flare for that exact reason.
$endgroup$
– Ben
1 hour ago
$begingroup$
Engines are never at idle on approach until the landing flare for that exact reason.
$endgroup$
– Ben
1 hour ago
add a comment |
1 Answer
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$begingroup$
They can. The Airbus A318 does this in steep approach mode. You can see spoilers extended in this video of a landing at London City Airport.
Going back further, the Lockheed L-1011 did this with a system called Direct Lift Control. When landing flaps were selected, spoilers raised a set amount. Small movements on the yoke raised or lowered the spoilers instead of adjusting the elevators. This made for a very smooth approach and landing.
The common point is that both these aircraft use electronics for spoiler control. It's too complicated to do this in a cable flight control system. You need to have the system retract the spoilers quickly in cases like go-around and stalls. As I recall, steep approach mode on the A318 activates a different set of gains on the flight control loops for better handling qualities in that configuration.
Finally, a number of fighters have the same system, and some glider pilots do this manually.
answered 1 hour ago
user71659user71659
3,500925
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add a comment |
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1 Answer
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1 Answer
1
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oldest
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active
oldest
votes
$begingroup$
They can. The Airbus A318 does this in steep approach mode. You can see spoilers extended in this video of a landing at London City Airport.
Going back further, the Lockheed L-1011 did this with a system called Direct Lift Control. When landing flaps were selected, spoilers raised a set amount. Small movements on the yoke raised or lowered the spoilers instead of adjusting the elevators. This made for a very smooth approach and landing.
The common point is that both these aircraft use electronics for spoiler control. It's too complicated to do this in a cable flight control system. You need to have the system retract the spoilers quickly in cases like go-around and stalls. As I recall, steep approach mode on the A318 activates a different set of gains on the flight control loops for better handling qualities in that configuration.
Finally, a number of fighters have the same system, and some glider pilots do this manually.
answered 1 hour ago
user71659user71659
3,500925
$endgroup$
add a comment |
$begingroup$
They can. The Airbus A318 does this in steep approach mode. You can see spoilers extended in this video of a landing at London City Airport.
Going back further, the Lockheed L-1011 did this with a system called Direct Lift Control. When landing flaps were selected, spoilers raised a set amount. Small movements on the yoke raised or lowered the spoilers instead of adjusting the elevators. This made for a very smooth approach and landing.
The common point is that both these aircraft use electronics for spoiler control. It's too complicated to do this in a cable flight control system. You need to have the system retract the spoilers quickly in cases like go-around and stalls. As I recall, steep approach mode on the A318 activates a different set of gains on the flight control loops for better handling qualities in that configuration.
Finally, a number of fighters have the same system, and some glider pilots do this manually.
answered 1 hour ago
user71659user71659
3,500925
$endgroup$
add a comment |
$begingroup$
They can. The Airbus A318 does this in steep approach mode. You can see spoilers extended in this video of a landing at London City Airport.
Going back further, the Lockheed L-1011 did this with a system called Direct Lift Control. When landing flaps were selected, spoilers raised a set amount. Small movements on the yoke raised or lowered the spoilers instead of adjusting the elevators. This made for a very smooth approach and landing.
The common point is that both these aircraft use electronics for spoiler control. It's too complicated to do this in a cable flight control system. You need to have the system retract the spoilers quickly in cases like go-around and stalls. As I recall, steep approach mode on the A318 activates a different set of gains on the flight control loops for better handling qualities in that configuration.
Finally, a number of fighters have the same system, and some glider pilots do this manually.
answered 1 hour ago
user71659user71659
3,500925
$endgroup$
They can. The Airbus A318 does this in steep approach mode. You can see spoilers extended in this video of a landing at London City Airport.
Going back further, the Lockheed L-1011 did this with a system called Direct Lift Control. When landing flaps were selected, spoilers raised a set amount. Small movements on the yoke raised or lowered the spoilers instead of adjusting the elevators. This made for a very smooth approach and landing.
The common point is that both these aircraft use electronics for spoiler control. It's too complicated to do this in a cable flight control system. You need to have the system retract the spoilers quickly in cases like go-around and stalls. As I recall, steep approach mode on the A318 activates a different set of gains on the flight control loops for better handling qualities in that configuration.
Finally, a number of fighters have the same system, and some glider pilots do this manually.
answered 1 hour ago
user71659user71659
3,500925
edited 1 hour ago
answered 1 hour ago
user71659user71659
3,500925
answered 1 hour ago
user71659user71659
3,500925
answered 1 hour ago
user71659user71659
3,500925
3,500925
add a comment |
add a comment |
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$begingroup$
Engines are never at idle on approach until the landing flare for that exact reason.
$endgroup$
– Ben
1 hour ago