Each MR implements the mechanism that defines when the task shall be completed. The previous and next due executions are recorded in the M.Works module.
The principal MR life-cycle options are:
1/ Defined repeat interval (eg. standard MPD tasks, the majority of ADs, life controlled parts...). This is the standard mode.
Note: The repeat interval can change depending on various elements (aircraft standard, component fitted, operation category, ...). If there is several thresholds / repeat interval, then several MRs all sharing the same reference but a different "part" must be created.
Note: An Airworthiness Directive (AD) may require several actions to be carried at different times (typically an AD might include a repetitive inspection requirement and a permanent modification). There shall be as many MRs having the same reference but different parts as there are actions in the AD.
2/ Event Driven: Use this mode when there is no pre-defined threshold / repeat interval and the task will be performed when another event occurs.
This option can be used to prepare pre-defined packages (Maintenance Blocs) and Tasks for works to be carried out when needed, such as "Engine Change", "APU change", "Propeller change", "Aircraft Exterior Paint", "Engine Preservation", ...
3/ One Time Action: Check the "One Time Action" box when the task is to be carried out one time only (without repeat interval).
Note: When the box "One Time Action" is checked, another check box "Standard (mod)" is displayed. Check the "Standard (mod)" box when the performance of this task is the embodiment of a modification.
4/ Triggering MR: When a task (with or without a pre-defined repeat interval) shall be performed within a specified number of hours, cycles or months after another maintenance task has been carried out, use the triggering MR function:
When a MR (MR#1) is triggered by another MR (MR#2), the next due of all open WOs associated with MR#1 will be automatically updated when:
i) MR#2 is performed (a WO is closed and complied with (C/W)); or
ii) MR#2 is a component position and a component is installed (TAG.I) in this position
In both cases, the execution of MR#1 become due after the latency defined as "triggering delay" on MR#1
Note: A Component position MR cannot be triggered by another MR, but a component position MR can trigger another MR
5/ Refer to MR: When a MR is never executed directly but its status is determined by reference to another MR. The most common examples of utilization are:
- When the status of an FAA AD is determined by referring to the associated EASA AD (in this example the FAA AD is deemed to be an administrative coverage for the EASA AD)
- When the MR exists for administrative coverage of the documents listed as "Document of Reference" (like an MRB item) but the actual task is covered by another document like an Engineering Order.
Note: The MR which is referred by other MRs (as Refer to MR) shall be the document actually ordered on the field with the full maintenance instructions