In aviation, "Hard Time" refers to the specified lifespan of a particular component, often measured in aircraft hours, aircraft cycles, or calendar days. This limitation is established by the original equipment manufacturer (OEM) based on their engineering and reliability assessments.

When a component reaches its specified hard time limit, a predefined action is required. This action could involve overhauling the component, conducting bench testing, or outright replacement. This is crucial to ensure the continued airworthiness of the component and, consequently, the entire aircraft.

Monitoring and adhering to hard time limits are essential for maintaining the airworthiness of an aircraft. This is not only a regulatory requirement but also a safety measure to prevent failures or malfunctions that could compromise the safety of the aircraft and its occupants.