In the 1980s, Rolls-Royce plc reinstated the program to provide the operator with a fixed engine maintenance cost over an extended period of time. A complete engine and accessory replacement service was provided, allowing the operator to accurately forecast this cost, and relieving him from purchasing stocks of engines and accessories. The term was coined by Bristol Siddeley in 1962 to support Vipers of the British Aerospace 125 business jets for a fixed sum per flying hour. This concept of unscheduled maintenance was initially introduced for aircraft engines to mitigate engine failures. Power-by-the-Hour Ī Power by the Hour program provides budget predictability, avoids installing a loaner during repairs when an aircraft part fails and enrolled aircraft may have a better value and liquidity. Packages are constructed by dividing the maintenance tasks into convenient, bite-size chunks to minimize the time the aircraft is out of service, to keep the maintenance workload level, and to maximize the use of maintenance facilities. Main article: Aircraft maintenance checksĪircraft maintenance in civil aviation generally organized using a maintenance checks or blocks which are packages of maintenance tasks that have to be done on an aircraft after a certain amount of time or usage.