Radar Flight Following
Radar flight following is a radar service provided by air-traffic control (ATC) that keeps aircraft in positive radar control throughout the entirety of the flight. Radar flight following starts when the pilot request it, usually at the time of takeoff, to the when pilot cancels it usually at the time of landing. It is accomplished through ATC doing what is called a handoff to different controllers either in other towers or center agencies. A handoff is when one controller gives communicational and directional control of an aircraft in their airspace to another controller, either in the same tower or different agency either right before but not later then the aircraft leaving their controlling airspace.
In order to receive radar flight following the pilot must request it. The controller cannot give it to the pilot without his request due to federal aviation regulations. Radar flight following is commonly known as VFR flight following. It is most often used by aircraft flying VFR, pilot students doing cross-country flights, or any other type of flight that requires the traveling of long distances in visual flight. When flying IFR, or by instruments, an aircraft is automatically under ATC control and needs not to request radar flight following. In order to obtain radar flight following the pilot needs to call up the approach or departure controlling agency for that area and request it directly from ATC.
During radar flight following, ATC will provide positive separation between all aircraft under their control. The primary purpose of ATC is to provide separation between VFR and IFR traffic while maintaining the expeditious flow of traffic in and out of airports safely. However, not all VFR aircraft are under ATC control and thus unless requested, ATC does not have to provide positive separation between those aircraft in and out of radar flight following. Due to this, it is widely recommended by the FAA that all pilots flying long distance cross-country flights do so under radar flight following.