PCAS allows pilots, particularly in single pilot VFR aircraft, an additional instrument to increase their situational awareness of other aircraft operating nearby. A basic system will notify pilots of the nearest transponder equipped aircraft, its relative height and distance, and importantly if the distance is decreasing or increasing. More advanced systems can integrate with EFIS, overlaying nearby aircraft on the GPS map with relative height information. This information reduces pilot work loads in busy airspace. It may also help pilots to hone their ability to spot nearby aircraft by alerting them when an aircraft is near.