Abstract: A latch pin actuator (34) for use in connection with an aircraft (10) having folding wings or wing tips (12). The actuator (34) includes housing (38) mountable to a wing portion (12, 16). A latch pin (21) in the form of a hydraulic cylinder is slidably mounted within the housing (38) and on a piston (44) which is fixed to the housing (38). Variable volume fluid chambers (46, 48) are defined in the cylinder body of the latch pin (21). A primary lock member (58) is movable between locked and unlocked positions such that retraction of the latch pin (21) is prevented when the primary lock (58) is in a locked position. In preferred form, a hydraulic actuator (78) is used to move the primary lock member (58) between locked and unlocked positions and to operate a sequencing valve which delivers hydraulic pressure to a chamber (48) of the latch pin (21) after actuation of the primary lock (58).