Fixed Time Maintenance (FTM)

This is only effective where the failure mechanism of the item is clear time dependent, the item being expected to wear-out within the life of unit and where the total cost of such replacement is less than those of failure replacement repair. Thus the item is simple replaceable.

There are two main reasons for not adopting this policy for complex replaceable and adopted for simple replaceable items. Firstly the more complex item is assumed less likely exhibit failure and is time dependent and due to simple item failure if any becomes complex. Secondly, the complex items are expensive to replace or repair and subsequently exhibit "Foreign Maintenance" problems.