The NSD for a date-based task in aircraft maintenance program is determined in one of two ways as shown below.
If Last Performed Date & Time and Interval are available, NSD = Last Performed Date & Time + Interval.
If Last Performed Date & Time is not available although Threshold Value is available, NSD = Threshold Value + Ref. Date. (Note that the Ref. Date could be Operational Date or Induction Date of the aircraft as defined for the task in the aircraft/component maintenance program. If the Reference Date is not specified in the maintenance program, the Induction Date is assumed to be the Reference Date.)
If the task does not have 'Last Performed Date' , 'Initiated / Reset By' is set as "Self Compliance", 'Threshold Value' is not available and 'Repeat Interval' is entered, NSD = Reference Date (Induction / Operational date) + Repeat Interval.
The NSV for a usage-based task in aircraft maintenance program is computed in one of following ways as explained below:
If Last Performed Value and Interval are available; NSV = Last Performed Value + Interval.
If Last Performed Value is not available although Threshold Value is available; NSV = Threshold Value
If Last Performed Value and Threshold Value are not available although Interval and Last Performed Date & Time are available; NSV = Parameter Value on the Last Performed Date & Time + Interval.
If task does not have 'Last Performed Value', 'Initiated / Reset By' is set as "Self Compliance", 'Threshold Value' is not available and 'Repeat Interval' is entered, NSV is updated as "Repeat Interval".
The computation of NSD / NSV for a date-based task in a component maintenance program is as shown below, for various values of ‘Reset on Attachment?’, if Threshold / Interval is Available and 'Initiated / Reset By' set as "Self Compliance".
If the computed NSD/NSV for a task in aircraft/component maintenance programs as shown in various scenarios is earlier than the current date/less than the current parameter value, the system prompts you to specify the NSD/NSV for the task. However, the system accepts the NSD/NSV that you specify even if the NSD/NSV that is earlier than the current date/less than the present parameter value.
The system will not automatically compute the NSD/NSV, if the Initiated/Reset by” attribute for a task in the aircraft/component maintenance program is set to "Related Task Compliance”. However, if you have specified the NSD/NSV, then system retains these values.
If the task compiled has a short term escalation reference, sets the NSD/NSV of a task on the basis of the Schedule Reset Basis specified in the short term escalation request.
1. If the Schedule Reset Basis is set to “Actual Schedule”, the system derives NSD/NSV for tasks on the basis of the last performed date, as explained previously.
2. If the Reset Schedule Basis is set to “Last Schedule”, the system derives the NSD/NSV in the following way,
For date-based schedule: New NSD = NSD + Repeat Interval
For usage-based schedule: New NSV = NSV + Repeat Value
However, an exception to this would arise when a task with a short term escalation request was complied within positive tolerance limits. The system ignores the short term escalation request and computes the NSD/NSV on the basis of the last performed date, as explained previously.