Which type of SID involves flying a preplanned heading and altitude after takeoff?

The correct answer is Radar Departure. This type of Standard Instrument Departure (SID) involves the use of radar to provide air traffic control instructions that guide the aircraft safely away from the airport. After takeoff, the aircraft follows a preplanned heading and altitude as directed by air traffic control, which is provided through radar service. This method allows for real-time adjustments and clearances that ensure the safe separation of aircraft and efficient use of airspace.

RNAV Departures, which involve predefined routes based on satellite navigation, require compliance with specific waypoints but do not necessarily rely on radar guidance for headings and altitudes immediately after takeoff. Hybrid Departures may incorporate features of both RNAV and radar, but they do not strictly define the same direct control that characterizes a Radar Departure. Direct Departures generally mean the aircraft can fly directly to a defined point without the necessity of adhering to a SID, which does not involve the level of radar control typically present in a Radar Departure scenario.