What is Off-Block Time (OBT)?

Off-Block Time (OBT) is the time that an aircraft departs from the parking position.

Off-Block Time - Terminology

Airport Collaborative Decision-Making (A-CDM) specifies different terms for OBT:

• ‍SOBT (Scheduled Off Block Time): The time that an aircraft is scheduled to depart from the parking position.
• ‍EOBT (Estimated Off Block Time): The estimated time that an aircraft will start movement associated with departure.
• ‍TOBT (Target Off Block Time): The time that an aircraft Operator or Ground handler estimates that an aircraft will be ready to startup/pushback immediately upon reception of clearance from the tower.
• ‍TSAT (Target Start Up Approval Time): The time provided by ATC taking into account TOBT, CTOT and/or the traffic situation that an aircraft can expect start up/push back approval.
• ‍AOBT (Actual Off Block Time): The time the aircraft pushes back / vacates parking position.

Further Reference

• Airport Collaborative Decision Making (A-CDM) Implementation Manual, Eurocontrol