Which assignment type is eligible for ADD days?

The assignment type eligible for ADD days is composite lines. Composite lines refer to a combination of multiple flight segments that are scheduled together, which often require additional days to accommodate the complex itinerary or layover patterns. These assignments can include a mix of trip types and may not fit neatly into simple one-way or round trip definitions, thus necessitating the need for additional days for proper rest and regulatory compliance.

By allowing ADD days for composite lines, it ensures that crew members have sufficient time for rest and recovery, adhering to safety regulations regarding crew duty limits and rest periods. This flexibility is crucial, especially when dealing with the intricacies of overlapping flight schedules that composite lines might present.

The other assignment types, such as round trips, one-way trips, and short layovers, typically have different regulations regarding duty days and rest requirements that do not involve the same level of complexity or need for additional days.