Landing gear bogie pitch trimmer

1. 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;

a flow control valve for controlling flow of the hydraulic fluid through the fluid interface in use;

a gas-chargeable accumulator configured to be charged by a gas bottle;

wherein the gas-chargeable accumulator is in fluid communication with the flow control valve; and

wherein the gas-chargeable accumulator is configured to deliver the hydraulic fluid to the hydraulic actuator in use.

2. The landing gear bogie pitch trimmer according to claim 1 , comprising a terminal that is connected to the gas-chargeable accumulator, wherein the terminal is for connection to a monitor for monitoring a characteristic of the gas-chargeable accumulator.

3. The landing gear bogie pitch trimmer according to claim 1 , comprising a non-return valve for restricting or preventing flow of hydraulic fluid in a direction from the gas-chargeable accumulator towards the fluid interface.

4. The landing gear bogie pitch trimmer according to claim 1 , configured so that, in a first position of the flow control valve, a first side of the hydraulic actuator is in fluid communication with the fluid interface via the flow control valve, so that the hydraulic actuator is actuated to move the landing gear bogie by the flow of hydraulic fluid in use.

5. The landing gear bogie pitch trimmer according to claim 4 , configured so that, in a second position of the flow control valve, the first side of the hydraulic actuator is in fluid communication with a second side of the hydraulic actuator.

6. The landing gear bogie pitch trimmer according to claim 1 , comprising a second fluid interface, wherein the hydraulic actuator is selectively fluidly connectable to the second fluid interface to permit the flow of hydraulic fluid from the hydraulic actuator out of the landing gear bogie pitch trimmer via the second fluid interface.

7. The landing gear bogie pitch trimmer according to claim 6 , comprising a second non-return valve for restricting or preventing flow of hydraulic fluid from the second fluid interface towards the hydraulic actuator.

8. The landing gear bogie pitch trimmer according to claim 6 , wherein the second fluid interface is the fluid interface.

9. A system, comprising:

a landing gear bogie pitch trimmer; and

a hydraulic landing gear extension and retraction system for extending and retracting a landing gear upon which a landing gear bogie is mounted, the hydraulic landing gear extension and retraction system having a hydraulic fluid supply line;

wherein the landing gear bogie pitch trimmer comprises:

a hydraulic actuator for adjusting a pitch of the landing gear bogie, in use;

a fluid interface for connection to the hydraulic fluid supply line of the hydraulic landing gear extension and retraction system for receiving hydraulic fluid for use in actuating the hydraulic actuator;

a flow control valve for controlling flow of the hydraulic fluid through the fluid interface in use;

a gas-chargeable accumulator configured to be charged by a gas bottle;

wherein the gas-chargeable accumulator is in fluid communication with the flow control valve; and

wherein the gas-chargeable accumulator is configured to deliver the hydraulic fluid to the hydraulic actuator in use.

10. The system according to claim 9 , wherein the hydraulic fluid supply line of the hydraulic landing gear extension and retraction system is fluidly connected to the fluid interface of the landing gear bogie pitch trimmer.

11. The system according to claim 10 , configured so that operation of the hydraulic landing gear extension and retraction system causes operation of the flow control valve of the landing gear bogie pitch trimmer in use.

12. A landing gear controller to control a flow control valve of a landing gear bogie pitch trimmer, the flow control valve for controlling flow of a hydraulic fluid through a fluid interface of the landing gear bogie pitch trimmer from an aircraft hydraulic system external to the landing gear bogie pitch trimmer, wherein the landing gear controller is configured to:

determine, based on at least one predetermined criterion based on the characteristics a gas-chargeable accumulator configured to be charged by a gas bottle, to whether a flow of hydraulic fluid through the fluid interface is to be permitted by the flow control valve; and

when it is determined that the flow of hydraulic fluid through the fluid interface is to be permitted, cause the flow control valve to be in an open position to permit flow of hydraulic fluid through the fluid interface.

13. The landing gear controller according to claim 12 , configured to receive a signal indicative of a characteristic of the gas-chargeable accumulator of the landing gear bogie pitch trimmer.

14. The landing gear controller according to claim 12 , configured to cause the flow control valve to open immediately before and/or after extension and/or retraction of a landing gear upon which the landing gear bogie pitch trimmer acts.

15. The landing gear controller according to claim 12 , configured to cause the flow control valve to open during extension and/or retraction of a landing gear upon which the landing gear bogie pitch trimmer acts.