Mean Time Between Failures is closely related to failure rate. If the likelihood of failure is constant with respect to time (for example, in some product like a brick or protected steel beam), and ignoring the time to recover from failure, failure rate is simply the inverse of the Mean Time Between Failures (MTBF). MTBF is an important specification parameter in all aspects of high importance engineering design–such as naval architecture, aerospace engineering, automotive design, etc.–in short, any task where failure in a key part or of the whole of a system needs be minimized and stopped, particularly where lives might be lost if such factors are not taken into account. These factors account for many safety and maintenance practices in engineering and industry practices and government regulations, such as how often inspections and overhauls are required on an aircraft.