An auxiliary actuator (49) comprises a two stage telescopic hydraulic unit comprising first (59, 63) and second (56, 50) stage piston and cylinder actuators operating coaxially within an outer casing (50). A respective actuator is connected to a respective one of the strut (1) and bogie beam (4). The second stage actuator (56, 60) serves to control the tilt position of the bogie beam (4) relative to the strut (1). The second stage actuator (56. 60), when in the retracted position with the first stage actuator (59, 63) in the extended position, limits the length ol the auxiliary actuator (9) between its connections (62,67) to the strut (1) and bogie beam (4), so as to assume a predetermined intermediate length in which the bogie beam (4) is restrained to tilt about the auxiliary pivot (14) and thereby lengthens the landing gear during take-off.