A teeter flap lock for an aircraft may include at least one pair of diametrically positioned teeter flap lock plates extending from a rotor teetering hinge, spaced apart from a rotor mast of the aircraft. A teeter flap lock block is positioned about the rotor mast and is configured to fit between the teeter flap lock plates and the rotor mast. The teeter flap lock block fits between and contacts the teeter flap lock plates in an engaged position, and is movable between the engaged position and a disengaged position relative to the teeter flap lock plates. The teeter flap lock enables flapping of rotors coupled to the rotor mast via the teetering hinge when the teeter flap lock block is in the disengaged position and disables flapping of the rotors when the teeter flap lock block is in the engaged position.