The invention relates to a wind power installation comprising a rotor (6) which can be turned with wind power, and has a rotor hub (10) and at least one rotor blade (11) rotatably mounted thereon, a higher-level operation control device (15) and a blade angle adjustment system (16) communicatively connected to same and having components that can be used for the emergency deactivation of the wind power installation, by means of which system the rotor blade (11) can be rotated relative to the rotor hub (10) and can be thereby positioned in different blade angle positions, wherein control commands (54) for the positioning of the rotor blade can be output to the blade angle adjustment system (16) by the operation control device (15), and the blade angle adjustment system (16) follows the control commands (54) in a normal operation of the wind power installation and correspondingly positions the rotor blade (11), and wherein the blade angle adjustment system (16) also has a monitoring unit (50) that can run in parallel to the normal operation, by means of which the functionality of the or a portion of the components can be checked.