A latch mechanism for locking an aircraft folding wing is disclosed including at least one lug having an aperture and a latch pin moveable within the aperture between a latched configuration in which the latch pin is received in the aperture, and an unlatched configuration in which the latch pin is withdrawn from the aperture. At least part of one of the pin and the aperture has a hydrophobic coating. A hydrophobic coating may be applied to all apertures in the mechanism and/or to the latch pin. The provision of a hydrophobic coating helps to prevent the formation of moisture and hence ice on the latch pin and/or in the aperture, which ice can inhibit the pin from moving along the aperture into and out of its latching position.