What is Calculated Take Off Time (CTOT)?

Calculated Take Off Time (CTOT) is the time calculated and issued by the appropriate Central Management unit, as a result of tactical slot allocation, at which a flight is expected to become airborne. It is a term specified in the Airport Collaborate Decision Making (A-CDM).

CTOT is a key component of air traffic flow management (ATFM), and is used to ensure that flights depart in a safe and orderly manner. It is also used to coordinate between arrival and departure management, and to support dynamic capacity balancing (DCB).

CTOT is calculated based on a number of factors, including:

• The capacity of the airspace and airports
• The weather conditions
• The traffic mix
• The flight’s route and schedule

CTOT is typically issued to airlines a few hours before departure. Airlines are expected to adhere to their CTOT as closely as possible. If a flight is not able to depart at its CTOT, the airline must request a new CTOT from the Central Management unit.

CTOT is an important tool for ensuring the safety and efficiency of air travel. It helps to reduce congestion in the airspace and at airports, and it helps to ensure that flights arrive on time.

Here are some examples of how CTOT is used:

• If a flight is departing from a congested airport, the Central Management unit may assign it a CTOT that is later than its scheduled departure time. This will help to reduce congestion on the ground and in the air.
• If a flight is flying through bad weather, the Central Management unit may assign it a CTOT that is earlier than its scheduled departure time. This will help to ensure that the flight has enough time to reach its destination before the weather deteriorates.
• If a flight is departing from an airport that is experiencing delays, the Central Management unit may assign it a CTOT that is later than its scheduled departure time. This will help to ensure that the flight does not contribute to the delays.

CTOT is an essential tool for air traffic controllers and airlines. It helps to ensure the safety and efficiency of air travel.

References and Further Reading:

• Airport Collaborative Decision Making (A-CDM) Implementation Manual, Eurocontrol
• Take Off Time (TOT)
• ICAO Doc 7030/4 – EUR, Table 7
• ATFCM Users Manual – Flow management (CFMU)
• Flight Plan and ATFCM adherence for the safe and optimum flow of air traffic