An aircraft hydraulic actuation system for retracting an aircraft landing gear. The actuation system includes a supply line arranged to carry hydraulic fluid pressurized by a pump, a return line arranged to return hydraulic fluid to a reservoir, and a hydraulic actuator 128. In a first mode of operation, a first chamber 130 of the actuator 128 is supplied with pressurized hydraulic fluid from the supply line such that a piston 134 is moved in a first direction so as to move a load such as a landing gear. In a second mode of operation, the first chamber 130 is taken out of fluid communication with the supply line and a second chamber 132 is in fluid communication with the return line, such that the piston 134 is able to be moved under the influence of the load, for example when the landing gear extends under gravity.

An aircraft landing gear is disclosed having a landing gear leg attachable at a first end to an aircraft, and an axle beam, both the landing gear leg and the axle beam being rotatably mounted. The axle beam is rotatable between a first position, in which a first end of the axle beam is a first (shorter) distance from the first end of the landing gear leg, and a second position, in which said first end of the axle beam is a second (longer) distance from the first end of the landing gear leg. A biasing member is configured to be able to bias the axle beam towards the second position. An aircraft, a blended wing body aircraft, and a method of operating an aircraft are also disclosed.

Methods and apparatus for controlling landing gear retract braking are described. A controller is to determine an on-ground status of a wheel of a landing gear. The controller is to generate a control signal based on the on-ground status of the wheel. The control signal is to initiate a retract braking process for the wheel. The retract braking process is to decelerate the wheel from a first rate of rotation to a second rate of rotation less than the first rate of rotation.

Methods and apparatus for controlling landing gear retract braking are described. A controller is to determine an on-ground status of a wheel of a landing gear. The controller is to generate a control signal based on the on-ground status of the wheel. The control signal is to initiate a retract braking process for the wheel. The retract braking process is to decelerate the wheel from a first rate of rotation to a second rate of rotation less than the first rate of rotation.

Retraction of a landing gear assembly on an aircraft is actuated by a hydraulic actuator. The actuator includes a piston that travels within a cylinder along a stroke length between a first position corresponding to the landing gear assembly when extended and a second position corresponding to the landing gear assembly when retracted. The movement of the piston along its stroke length is snubbed at one end by a different amount according to the direction of travel, for example by use of an orifice plate that has a discharge coefficient that is greater in one direction than in the opposite direction. Asymmetric snubbing is thus provided, which enables the landing gear to retract faster.

Retraction of a landing gear assembly on an aircraft is actuated by a hydraulic actuator. The actuator includes a piston that travels within a cylinder along a stroke length between a first position corresponding to the landing gear assembly when extended and a second position corresponding to the landing gear assembly when retracted. The movement of the piston along its stroke length is snubbed at one end by a different amount according to the direction of travel, for example by use of an orifice plate that has a discharge coefficient that is greater in one direction than in the opposite direction. Asymmetric snubbing is thus provided, which enables the landing gear to retract faster.

Aircraft power system is disclosed having a hydraulic reservoir, a bi-directional hydraulic pump for pumping hydraulic fluid to and from the reservoir, and an electric motor. The electric motor is connectable to a first driveable component of the aircraft such that the electric motor is arranged to drive the first driveable component of the aircraft. The hydraulic pump is connectable to the first driveable component of the aircraft such that the hydraulic pump is arranged to pump hydraulic fluid from the reservoir to drive the first driveable component of an aircraft. Thus, in a first driveable mode of operation, the first driveable component is driven by both the electric motor and the hydraulic pump.

Aircraft power system is disclosed having a hydraulic reservoir, a bi-directional hydraulic pump for pumping hydraulic fluid to and from the reservoir, and an electric motor. The electric motor is connectable to a first driveable component of the aircraft such that the electric motor is arranged to drive the first driveable component of the aircraft. The hydraulic pump is connectable to the first driveable component of the aircraft such that the hydraulic pump is arranged to pump hydraulic fluid from the reservoir to drive the first driveable component of an aircraft. Thus, in a first driveable mode of operation, the first driveable component is driven by both the electric motor and the hydraulic pump.

The left and right main landing gears on an aircraft are normally controlled by separate hydraulic power packs (HPP). Each HPP is sized for the load of the respective main landing gear. During failure of one of the HPP, a backup valve actuates to allow the other HPP to operate both main landing gears. With the backup valve actuated, the pump of the functioning HPP is coupled to the reservoirs of both HPPs and to the load paths to both main landing gears.

The left and right main landing gears on an aircraft are normally controlled by separate hydraulic power packs (HPP). Each HPP is sized for the load of the respective main landing gear. During failure of one of the HPP, a backup valve actuates to allow the other HPP to operate both main landing gears. With the backup valve actuated, the pump of the functioning HPP is coupled to the reservoirs of both HPPs and to the load paths to both main landing gears.