Key Concepts

NOTE: Official procedures for A-CDM can be found in the relevant Aeronautical publications: i.e., Aeronautical Information Circulars (AIC), and Canada Air Pilot (CAP).

Target Off Block Time (TOBT)

TOBT is a reference time which indicates when an aircraft is expected to be ready to leave its stand. It is kept up-to-date by the aircraft operator or ground handler in order to provide a reliable estimate of when the aircraft is ready to depart from its parking position. TOBT must be updated if it is different from the previous TOBT by 5 minutes or more.

The TOBT is displayed on the Advanced Visual Docking Guidance System (AVDGS) at the stand, or communicated to the Flight Crew by the Aircraft Operator or Ground Handler where no AVDGS display is available or it is inoperative.

Target Start-Up Approval Time (TSAT)

TSAT represents the time an aircraft can expect to receive start-up and pushback approval. The TSAT takes into account the actual TOBT, variable taxi times to the assigned runway, expected deicing time, CTOT if applicable, and other real-time capacity and demand constraints at the airport.

The TSAT is displayed on the AVDGS at the stand, or communicated to the Flight Crew by the Aircraft Operator or Ground Handler where no AVDGS display is available or it is inoperative.

Target Take Off Time (TTOT)

TTOT is the time at which an aircraft is expected to be on the runway. It is equal to the TSAT plus the estimated taxi time to the assigned runway.

Calculated Take Off Time (CTOT)

The time calculated and issued by NAV CANADA, indicating when an aircraft should be airborne if it is to meet the constraints arising from the applicable Traffic Management Initiatives (TMI) (formerly referred to as APREQ).

Call Ready

The flight crew contacts the Apron Coordinator when the aircraft is ready for pushback, according to the procedures published in the relevant Aeronautical publications: i.e., Aeronautical Information Circulars (AIC), and Canada Air Pilot (CAP).

Call Ready must be made within +/- 5 minutes of TOBT. All doors must be closed, with boarding bridges removed, and all ground handling activities must be concluded. The tow bar and tractor must be connected to the aircraft. If the aircraft is not ready at this time, the flight crew must contact the airline or ground handler to update TOBT.

Pushback/Start-up approval

The Pre-departure sequence for aircraft is determined by the TSAT. The flight crew must ensure that the flight is ready to depart within 2 minutes of the push/start instruction having been issued.

Pushback/taxi instructions are issued to the flight crew from North or South Apron. Start-up approval will only be issued at +/- 5 min TSAT.

Share this page