Mean Time to Repair (MTTR)

Mean time to repair is the average time needed to restore a failed item to working condition, calculated as total repair or restoration time divided by the number of repairs, and used as a measure of maintainability and maintenance responsiveness.

MTTR equals the total corrective maintenance time in a period divided by the number of corrective maintenance actions. Organisations define its scope differently: some measure only active repair time, while others measure the full restoration time from failure until the equipment is back in production, including detection, response, diagnosis, waiting for parts, repair, testing and restart. Because the abbreviation is used for both, the definition in use should always be stated. MTTR is also sometimes expanded as mean time to recovery or mean time to restore.

MTTR is used to assess maintainability, which depends on equipment design, diagnostics, access, spare parts availability and staff skills, and to track the effectiveness of the maintenance organisation. Together with MTBF it determines inherent availability. Reducing MTTR often involves better fault diagnosis, prepared spares and tools, standard repair procedures, training, and modular designs that allow quick replacement.

Average repair times can hide a few very long outages, so many organisations also review the distribution of repair times and the longest events. Breaking restoration time into components, such as waiting for a technician or for parts, shows where delays arise. Repair work is governed by the OEM documentation, lockout and site safety procedures and qualified personnel; reducing MTTR should never come at the expense of safety.

Key points

MTTR equals total repair time divided by the number of repairs.
Scope varies: active repair time only, or full restoration time.
Together with MTBF, it determines inherent availability.
Improved by diagnostics, prepared spares, training and modular design.

Where AiVibe comes in

AiAmbA AI Factory use cases include predictive maintenance and visual inspection on textile, automotive and electronics lines. AiAmbA IoT normalises industrial signals from protocols such as OPC UA and MQTT, with driver availability confirmed per installation.

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Mean Time to Repair (MTTR)

Key points

Where AiVibe comes in

Related terms

Terms that refer to Mean Time to Repair (MTTR)