Variable Maximum Commandable Roll Rate for Directional Control During Engine-Out Rolling Maneuver
AssigneeThe Boeing Company
InventorsDaniel R. Shapiro, David Paul Eggold
Life of this patent
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Abstract
A system and a method for varying a maximum roll rate command for ensuring sufficient directional control during an engine-out rolling maneuver of a multi-engine aircraft. For a multi-engine airplane with a roll rate command flight control system, the primary flight control computer is used to vary the maximum commandable roll rate to preserve the desired control margins during roll maneuvers where the rudder is fully deflected to control a thrust asymmetry. When the engine-out yawing moment exceeds a specified value, the system sets a reduced limit on the amount of roll rate the pilot can command.
Claims20
A method of varying roll rate limits of an aircraft while flying with thrust asymmetry, comprising:
- (a) calculating a value of a flight parameter indicative of thrust asymmetry;
- (b) applying either a nominal maximum commandable roll rate or a reduced maximum commandable roll rate less than said nominal maximum commandable roll rate in a roll rate command system, said nominal maximum commandable roll rate being applied in response to said calculated flight parameter value being less than a lower threshold value, and said reduced maximum commandable roll rate being applied instead of said nominal maximum commandable roll rate in response to said calculated flight parameter value increasing from a value less than an upper threshold value to a value greater than said upper threshold value, said upper threshold value being greater than said lower threshold value;
- and
- (c) controlling deflection of control surfaces of the aircraft so that the roll rate of the aircraft, after receipt of a roll rate command from a pilot, does not exceed the applied maximum commandable roll rate.
A method of varying roll rate limits of an aircraft while flying with thrust asymmetry, comprising:
- (a) calculating a value of a flight parameter indicative of thrust asymmetry;
- (b) applying a maximum commandable roll rate in a roll rate command system, said maximum commandable roll rate being a function of said calculated flight parameter value when said calculated flight parameter value is in a range bounded by upper and lower threshold values;
- and
- (c) controlling deflection of control surfaces of the aircraft so that the roll rate of the aircraft, after receipt of a roll rate command from a pilot, does not exceed the applied maximum commandable roll rate.
A system for varying roll rate limits of an aircraft while flying with thrust asymmetry, comprising a computer system, first and second control surfaces, and first and second actuators respectively coupled to said first and second control surfaces, wherein said computer system is programmed to execute the following operations:
- (a) monitoring a value of a flight parameter indicative of thrust asymmetry as the aircraft flies with thrust asymmetry;
- (b) reducing a maximum commandable roll rate in response to said value of said flight parameter increasing from a value less than an upper threshold value to a value greater than said upper threshold value;
- and
- (c) controlling deflection of said first and second control surfaces of the aircraft via said first and second actuators so that the roll rate of the aircraft, after receipt of a roll rate command from a pilot, does not exceed said reduced maximum commandable roll rate.
A system for varying roll rate limits of an aircraft while flying with thrust asymmetry, comprising a computer system, first and second control surfaces, and first and second actuators respectively coupled to said first and second control surfaces, wherein said computer system is programmed to execute the following operations:
- (a) monitoring a value of a flight parameter indicative of thrust asymmetry as the aircraft flies with thrust asymmetry;
- (b) determining a maximum commandable roll rate, said maximum commandable roll rate being a function of said calculated flight parameter value when said calculated flight parameter value is in a range bounded by upper and lower threshold values;
- and
- (c) controlling deflection of said first and second control surfaces of the aircraft via said first and second actuators so that the roll rate of the aircraft, after receipt of a roll rate command from a pilot, does not exceed said maximum commandable roll rate.
A system for assuring a desired control margin on a multi-engine aircraft for roll maneuvers conducted with a large thrust asymmetry, comprising a computer system with logic to automatically reduce the limit on commanded roll rate when a flight parameter indicates asymmetric thrust conditions and additional rudder deflection is not available to achieve desired roll characteristics at higher roll rates.
Dependencies are inferred from the claim text.