An example aircraft includes (i) a landing gear having a chassis, an axle, and wheels mounted to ends of the axle; (ii) a hydraulic actuator including a cylinder, a first piston coupled to the chassis, and a second piston coupled to the axle; and (iii) a directional control valve including: inlet ports configured to be fluidly coupled to a source of pressurized fluid, tank ports configured to be fluidly coupled to a tank, and workports configured to be fluidly coupled to the hydraulic actuator.

An aircraft landing gear assembly has a main strut and a bogie beam pivotally coupled to the main strut via a coupling assembly. The coupling assembly is arranged to define a bogie beam pivot axis relative to the main strut which is spaced from the landing gear assembly, and perpendicular to the direction of travel. The coupling assembly has a pair of arms, each having an upper pivotal coupling to the main strut and a respective lower pivotal coupling to the bogie beam. Each arm has a respective connection axis which intersects respective axes of its upper pivotal coupling and lower pivotal coupling. The upper pivotal couplings and lower pivotal couplings are arranged such that their connection axes intersect at a virtual pivot axis which defines the bogie beam pivot axis.

Aircraft landing gear comprising a locking assembly including a pair of spaced-apart bearing pads and a lock member. The lock member is moveable between a locked position in which it engages the bearing pads to prevent pivotal movement of a steerable axle, and an unlocked position in which the member is disengaged from the bearing pads such that movement of the axle can occur. The lock member has a guide surface on either side for guiding the member and bearing pads into alignment during movement of the member from the unlocked to the locked position. The guide surface comprises a first inclined portion for moving the member towards alignment with the bearing pads and a second inclined portion, spaced apart from the first portion, for moving the member into alignment with the bearing pads such that the member and bearing pads are aligned in a movement comprising two stages.

The invention relates to an aircraft undercarriage provided at its bottom end with a rocker arm (2) carrying at least two axles (4, 5), including one in front of a hinge between the rocker arm and the undercarriage and the other behind said hinge. According to the invention, one of the axles is fitted with one or more braked wheels (6) and the other axle is fitted with one or more motor-driven wheels (8).

Disclosed is a landing gear bogie pitch trimmer, comprising a hydraulic actuator for adjusting a pitch of a landing gear bogie, in use, a fluid interface for receiving, from an aircraft hydraulic system external to the landing gear bogie pitch trimmer, hydraulic fluid for use in actuating the hydraulic actuator, and a flow control valve for controlling flow of the hydraulic fluid through the fluid interface in use. Also disclosed is a system, a landing gear controller, a method, and an aircraft.

A centre seeking actuator having an outer cylinder, a slave cylinder slidably disposed within the outer cylinder, and a rod assembly having a piston slidably disposed within the slave cylinder and a rod extending from the piston to a point outside the outer cylinder. One or more first dynamic seals are arranged to act on a side wall of the rod to inhibit working fluid leaking from the outer cylinder, and one or more second dynamic seals are arranged to act on a sidewall of the slave cylinder to inhibit working fluid leaking from the outer cylinder.

The invention relates to an aircraft undercarriage provided at its bottom end with a rocker arm (2) carrying at least two axles (4, 5), including one in front of a hinge between the rocker arm and the undercarriage and the other behind said hinge. According to the invention, one of the axles is fitted with one or more braked wheels (6) and the other axle is fitted with one or more motor-driven wheels (8).

An aircraft landing gear assembly having: a bogie beam coupled to a strut; a steerable axle mounted on the bogie beam, first and second wheel assemblies, mounted on the axle, each wheel assembly including a wheel and a brake disc attached to each wheel and arranged to rotate with the wheel; first and second brake plates mounted on the axle arranged to provide a braking force to the wheels upon contact with the first and second brake discs; a cross member coupled between the first and second brake plates; a brake rod, pivotally connected to the cross member at a first end and arranged to be attached to an anchor point on the aircraft landing gear at a second end; wherein the pivot axis of the axle and the pivot axis of the cross member are generally coaxial.

A controllable aircraft taxi system is provided that enables the simultaneous control of aircraft autonomous ground movement and direction of aircraft autonomous ground movement. Independently controlled non-engine drive means capable of driving an aircraft landing gear wheel to move an aircraft autonomously on the ground without reliance on the aircraft's main engines are mounted to provide driving torque to aircraft a selected number of main landing gear wheels. The aircraft nose landing gear steering system is provided with steering angle detection and measurement means adapted to communicate with main landing gear wheel non-engine drive means, enabling simultaneous control over both autonomous aircraft ground travel and direction of autonomous aircraft ground travel. The present invention overcomes steering challenges presented by using non-engine drive means on main landing gear wheels to drive aircraft autonomously during taxi.