What does the phrase "Clearance to Depart" typically signify?

The phrase "Clearance to Depart" signifies that air traffic control has given permission for the aircraft to begin taxiing. This clearance is a critical component of the flight operations process, as it indicates that the aircraft is ready to move and that the runway or taxiway is clear for the aircraft to proceed safely.

In this context, clearance to depart is a formal communication that ensures the aircraft can transition from the ramp area to the active runway or taxiway, adhering to all safety protocols and procedures. It follows prior communications regarding flight plans and readiness checks and is a crucial step in the departure sequence of an aircraft.

The other options relate to different processes within aviation operations but do not accurately describe what "Clearance to Depart" entails. For instance, permission to board passengers involves cabin crew readiness, while engine computations are related to pre-flight checks rather than the act of departing. Checking fuel levels is a safety measure that happens prior to departure clearance, but it is not what the phrase signifies directly.