	Related Topics:
	Preventive Tasks

Preventive Maintenance Intervals and Duration

It is possible within the simulation for more than one preventive task to take place on the same block simultaneously. One way that this can occur is if the following conditions are met:

Sufficient crews and spare parts are available to perform all of the preventive tasks that are requested.

and

You have specified a duration for a preventive task that exceeds the interval specified between preventive tasks.

For example, assume that you have a crew that can perform unlimited simultaneous tasks, you have specified that the preventive task takes 10 hours to complete and you have also specified that the preventive task will be performed every 5 hours of system time. In this case, the following will occur:

The preventive task will begin for the first time at 5 hours and end at 15 hours.
The preventive task will begin for the second time at 10 hours (during the first preventive maintenance action) and end at 20 hours.
The preventive task will begin for the third time at 15 hours (during the second preventive maintenance action) and end at 25 hours.
And so on...

It is also possible within the simulation for more than one preventive task to take place on the same block at or around the same time. This can occur when multiple “triggers” have been defined in the Maintenance Task window. For example, if you have assigned two preventive tasks to a block, one configured to be performed every 100 hours (of system time) and the other configured to be performed upon maintenance of another group item, it is possible that the maintenance of another group item will occur at, or around, the 100 hour interval.

If the multiple “trigger” events occur at exactly the same time, then only one preventive task will take place.
If the multiple “trigger” events occur close together in time but not at exactly the same time, then multiple preventive tasks will take place and, given sufficient crews, this may result in multiple preventive tasks on the same component at the same time.

Therefore, in the example above, if the maintenance of another group item occurs at exactly the same time as the 100 hour interval (e.g., at 100 hours, 200 hours, etc.) then only one preventive task will take place. If the maintenance of the other group item occurs around but not exactly on the 100 hour interval (e.g., at 100 hours + 1 minute, 201 hours, etc.) then this may result in two overlapping preventive tasks for the component.