When Maintenance events are created for an Aircraft, they will be assigned one of the following statuses:
Offline (red)
Aircraft has any InProgress maintenance events (not tied down to a particular date range)
Aircraft Unserviceable
Alert Triggered (orange/amber)
Aircraft has any maintenance events that is neither Completed nor Cancelled , with any enabled alert(s) triggered
(for the last rule (the third checkbox in the screenshot below) -- the enabled status is ignored. If disabled, the Due Date is cleared to then check if it becomes overdue)
Aircraft Unserviceable
Overdue (orange/amber)
Aircraft has any Confirmed ( maintenance events and is either Unscheduled (no Start and End date), or starts before or on today and ends after or on today
Aircraft Unserviceable
Online (green)
Aircraft has no maintenance events that meet any of the conditions above
Aircraft Serviceable