Description

Mean Time Between Unscheduled Removal (MTBUR) is calculated by dividing the flight hours (of a fleet) by the number of unscheduled removals of a component. This is an operational measurement. If all removals were because of actual component failure then MTBUR would be equivalent to Mean Time Between Failure (MTBF), but that is not usually the case and so MTBUR is usually less than MTBF.