What is the difference between 4-D Trajectory Management and a 4-D contract?
4-D Trajectory Management is a fundamental principle of SESAR: it is the process that captures the overall traffic situation in the NOP and controls the development of the business or mission trajectories (BDT to SBT to RBT) in 4 dimensions (latitute, longitude, flight-level and time). Specifically, 4-D Trajectory Management is the process by which the Business Trajectory of the aircraft is established, agreed, updated and revised. This is achieved through Collaborative Decision Making processes between the aircraft operator, ATM and Airports (where applicable) except in time-critical situations when only Flight Crew and Controller are involved. [4-D Trajectory Management takes place from the time when the SBT is first shared until it arrives at the gate at its destination.] A 4-D contract is an ATC clearance that prescribes the containment of the trajectory in all 4 dimensions for the period of the contract during which the uncertainty associated with the future predicted position doe
