How do you calculate maintenance reserves of an aircraft?

Maintenance reserves are given in written in all leasing agreements. They are calculated based mainly on the projected utilisation ratio of the aircraft, which is the aircraft hours over the aircraft landings (cycles). The lower the ratio, the higher the MRs. Usually they are paid for the following: Airframe Engines (performance restoration) Engines (LLPs) Landing gear APU They're actually very important and have to be agreed upon during the negotiation of the contract since they affect, amongst other things, the monthly lease rate.