Question about crossing controls in your aircraft
Join Date: Dec 2015
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I'll try to keep this short and sweet, I'd appreciate short and sweet answers too, and any additional relevant information if you have it.
I would appreciate it a lot if you could include the type of aircraft you're talking about. Sim experiences also welcome.
I'd like to know if putting in full rudder and opposite aileron in your aircraft is enough to provide reasonable pitch control in the case that you've lost control of your elevator or trim.
Can the nose be kept above the horizon in this condition using the rudder? If so, is there enough aileron to prevent the nose from coming up too high without having to start banking in the opposite direction, or do you let up on the rudder? Any important speeds to know about to do this? How does having the boards full out on one wing affect the pitch and speed on your aircraft?
This is just a personal curiosity of mine.
Thanks.
I would appreciate it a lot if you could include the type of aircraft you're talking about. Sim experiences also welcome.
I'd like to know if putting in full rudder and opposite aileron in your aircraft is enough to provide reasonable pitch control in the case that you've lost control of your elevator or trim.
Can the nose be kept above the horizon in this condition using the rudder? If so, is there enough aileron to prevent the nose from coming up too high without having to start banking in the opposite direction, or do you let up on the rudder? Any important speeds to know about to do this? How does having the boards full out on one wing affect the pitch and speed on your aircraft?
This is just a personal curiosity of mine.
Thanks.
I'm also assuming that in this situation you would just point your aircraft to a runway and would like to know how to land with the least possible damage.
The problem is, the rudder will only increase fuselage lateral angle of attack (also known as sideslip). It will do nothing to the wings angle of attack (the more common one when looking at lift)
Fuselage lift will be a thing, if you're in a full deflection sideslip. However there is little chance you could do a flare by adding fuselage lift.
First of all, because adding fuselage lift means adding much drag, so speed loss and wing lift loss.
Second, most aircraft will have little bank (like 10° tops) even with full rudder deflection, so fuselage lift will be very limited : sin10° = 17%.
So you will get 17% of the lift effet but 100% of the drag effect.
It is not promising.
Join Date: Jan 2006
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In general the rudder pedals are best left alone in all airliners. Except for engine out or crosswind landings or takeoffs.
Can you use them, with care, if you're in an extreme attitude? If that's the last option go ahead. But it's not the primary or first option to choose. How many of us will experience those attitudes in an airliner during our career? Almost none of us.
In the AA 587 A300 crash the rudder pedals were moved rapidly back and forth several times. Rudder movement by itself wasn't the problem. The rapid changing from one rudder input to the other increased the load. The tail failed above the design and certification limit after the 4th(?) rudder reversal.
From the NTSB -
"The Safety Board found that the first officer, who was the flying pilot, inappropriately manipulated the rudder back and forth several times after the airplane encountered the wake vortex of a preceding Boeing 747 for the second time. The aerodynamic loads placed on the vertical stabilizer due to the sideslip that resulted from the rudder movements were beyond the ultimate design strength of the vertical stabilizer. (Simply stated, sideslip is a measure of the "sideways" motion of the airplane through the air.)
The Board found that the composite material used in constructing the vertical stabilizer was not a factor in the accident because the tail failed well beyond its certificated and design limits."
Can you use them, with care, if you're in an extreme attitude? If that's the last option go ahead. But it's not the primary or first option to choose. How many of us will experience those attitudes in an airliner during our career? Almost none of us.
In the AA 587 A300 crash the rudder pedals were moved rapidly back and forth several times. Rudder movement by itself wasn't the problem. The rapid changing from one rudder input to the other increased the load. The tail failed above the design and certification limit after the 4th(?) rudder reversal.
From the NTSB -
"The Safety Board found that the first officer, who was the flying pilot, inappropriately manipulated the rudder back and forth several times after the airplane encountered the wake vortex of a preceding Boeing 747 for the second time. The aerodynamic loads placed on the vertical stabilizer due to the sideslip that resulted from the rudder movements were beyond the ultimate design strength of the vertical stabilizer. (Simply stated, sideslip is a measure of the "sideways" motion of the airplane through the air.)
The Board found that the composite material used in constructing the vertical stabilizer was not a factor in the accident because the tail failed well beyond its certificated and design limits."
