Validation projects

Pre-departure sequencing supported by route planning

Release: 2014

Reference: -

Location: London-Gatwick


Pre-departure management delivers optimal traffic flow to the runway by factoring in accurate taxi time forecasts and route planning. The planned pre-departure sequences are used to assign to each flight a target start-up approval time (TSAT) that takes into account the gate where the aircraft is parked and how long it takes for the aircraft to taxi to the departure runaway. Tower clearance delivery controllers follow the TSAT-window when issuing start-up approval.

The solution allows for:

• Reduced waiting time at the runway holding point, which saves fuel and allows workload efficiency;

• Increased accuracy of taxi time-out predication and hence take-off time predictability, which in turn allows the aircraft to adhere to their target take-off time (TTOT);

• Provision of a more stable pre-departure sequence.

These improvements in turn may be used by the Network Manager (NM) to optimise network management.

Validation results

Exercises at London Gatwick validated the use of routeplanning information provided by A-SMGCS for departure management (DMAN) compared to static tables used in current airport collaborative decision making (A-CDM). The results indicated that the solution allowed for more accurate calculation of an integrated arrival and departure sequence. The solution also allowed for increased predictability and stability of actual times and target times for taxi-out. The exercises noted that the benefits of estimating taxi times based on the routing functionality compared to static taxi time tables used in A-CDM can vary due to a number of factors:

• The level of sophistication of the static taxi time tables: estimated taxi times offer fewer benefits when the tables are sophisticated; Complexity of the taxi layouts: airports with a complex taxi layouts benefit more;

• Taxi route length: airports where taxi route lengths can vary significantly benefit the most from taxi times calculated by the A-SMGCS routing and planning function. While during nominal situations the validation results did not show major improvements of both TTOT and TSAT accuracy; during non-nominal situations (e.g. closed taxiway) slight improvements of both TTOT and TSAT accuracy were reported.


The validation results for this solution are conclusive and sufficient to support a decision for industrialisation. DMAN synchronised with pre-departure sequencing is planned for deployment at 24 European airports in accordance with the PCP.