Abstract: A hub-protecting cap for use with a helicopter. The helicopter has a fuselage, a tail rotor assembly operatively coupled to the fuselage for rotation relative to the fuselage about a tail rotor axis, at least one tail rotor blade detachably connected to the tail rotor assembly, a retention pin, and a pitch control link mechanism. The hub-protecting cap comprises a cap body portion, a pin-receiving aperture, and a link-attaching portion. The cap body portion is adapted to be attached to a hub portion of the tail rotor assembly in a manner to cover the hub portion when the tail rotor blade is detached from the tail rotor assembly. The cap body portion has a hub socket adapted such that pitch change bearing surfaces of the hub portion are within the hub socket of the cap body portion when the cap body portion is attached to the hub portion. The pin-receiving aperture is through the cap body portion.