From an excerpt from the 777, "Use of Rudder on Transport Category Airplanes", in response to NTSB Recommendations.
Explain to Flight Crews that a full or nearly full rudder deflection in the opposite direction, or certain combinations of sideslip angle and opposite rudder deflection can result in potentially dangerous loads on the vertical stabilizer, even at speeds below the design maneuvering speed.
Response: Boeing airplanes are designed to withstand the structural loads generated by a full rudder input out to the airplane's maximum operating airspeed, Vmo/Mmo. Some Boeing airplanes meet these requirements out to the design dive speed. This means the structure has at least a 50% safety margin over the maximum load generated by this kind of maneuver. As previously mentioned, Boeing airplane vertical fins can also sustain loads if the rudder is rapidly returned to neutral from the over yaw sideslip or the rudder is fully reversed from a full steady state sideslip. Boeing airplanes are not designed to a requirement of full authority rudder reversals from an "over yaw" condition. Sequential full or nearly full authority rudder reversals may not be within the structural design limits of the airplane, even if the airspeed is below the design maneuvering speed. There are no Boeing Procedures that require this type of pilot input. It should also be pointed out that excessive structural loads may be generated in other areas of the airplane, such as engine struts, from this type of control input. In addition, large sideslip angles may cause engine surging at high power settings.
It is important to note that use of full rudder for control of engine failures and crosswind takeoffs and landings is well within the structural capability of the airplane.
Originally Posted by
misd-agin
AAMP never advocated 'kicking' the rudder which is an unfortunate term others have used. The AAMP tape, referenced in the NTSB report, actually says to be careful using the rudder at low airspeed and high AOA. "Too much is actually the spin entry technique, isn't it?"(paraphrased)
From the 777 manual
Boeing recommends that:
· Transport pilots should be made aware that certain prior experience or training in military, GA, or other non-transport aircraft that emphasizes use of rudder input as a means to maneuver in roll typically does not apply to transport aircraft or operations.
· Transport pilots should be made aware that certain prior experience or training in military, GA, or other non-transport aircraft types emphasizing the acceptability of unrestricted dynamic control application typically does not apply to transport aircraft or operations. Excessive structural loads can be achieved if the aircraft is maneuvered significantly different than what is recommended by the manufacturer or the operator's training program.
In simple pilot terms, the rudder in a large transport airplane is typically used for trim, engine failure, and crosswind takeoff and landing. Only under an extreme condition, such as loss of a flap, mid air collision, or where an airplane has pitched to a very high pitch attitude and a pushover or thrust change has already been unsuccessful, should careful rudder input in the direction of the desired roll be considered to induce a rolling maneuver to start the nose down or provide the desired bank angle. A rudder input is never the preferred initial response for events such as a wake vortex encounter, windshear encounter, or to reduce bank angle preceding an imminent stall recovery.
Seems AA does not agree with what even Boeing recommends.
And ..
Q. What pilot action should I take to recover when I encounter wake turbulence?
A- Normal piloting actions for roll control are sufficient for large commercial jet transports. If a roll off does occur, the normal use of ailerons and spoilers should be sufficient to recover. The use of rudder is not recommended.
The induced roll from the vortex will be more severe for short span airplanes (relative to the aircraft that generated the vortex) but the recovery procedures are the same. Crews should perform the upset recovery procedures if bank angles of greater than 45 degrees are encountered.