How maintenance due dates affect the schedule

A maintenance requirement coming due is worked out against every booking before the day, so nobody has to remember which aircraft are close to a check. The schedule projects the aircraft forward from its counters and flags the booking ahead of time.

Due is not the same as grounded

A check falling due mid-flight is rarely a hard stop. Most training aircraft may apply a tolerance to a scheduled check, and FlyerOS reads that tolerance from your own maintenance programme rather than assuming one. So a booking gets one of three answers:

• Clear, if the flight lands before the requirement is due.
• Your call, if it lands past the due point but inside the tolerance in your programme. FlyerOS says so, shows both figures, and notes that the next interval runs from the actual inspection, not from the due point. The flight is still lawful; the decision is yours.
• Refused, if it lands beyond the tolerance, or the requirement has no tolerance.

A school that wants to be stricter than the tolerance can set the rule to block, which is the layering working as intended: you may always be stricter than the regulation, never looser.

Why forward projection matters

Checking "is it due now?" is too late. Because the schedule looks ahead to the time of each flight, it can tell you on Monday that Friday's long trip would take the aircraft past its check, while there is still room to plan the work in.

Grounded is different

An aircraft grounded by a defect, a directive or a work order is genuinely out of the calendar, and its bookings are flagged the same way. That is a hard stop, not a forecast. See Reporting a defect for unplanned work.