All four aspects may drive SA processes. Being aware of the status of particular objects (cues), one might infer that particular situations are on-going, and frame the objects accordingly. The cues then drive re-framing of situations. Having a particular frame, or pre-conception of a situation, this may drive the perception of objects. having noticed that a landing is about to occur, an Air Traffic Controller will usually look for specific objects in the environment and update the awareness of their status. Further, having realized the implications of objects of their status, this drives the process of what to attend to next. knowing that a vehicle is approaching a runway where a landing is about to take place, an Air Traffic Controller may monitor its progress. Event horizon awareness may also guide SA, . if one plans to stop the car at a gas station, one may look for gas station signs.