Aviation Navigation

Separation of Air Traffic and Rules

As in all aspects of life there are rules and regulations that affect flying. Some rules are just good common sense practices while others are habits acquired through specific training. All of these rules exist because safety in the skies is the most important consideration of all.

There are some basic flying common sense rules in which all pilots and air traffic controllers are trained. Some are given below.

For most small aircraft flying outside controlled airspace in good weather, the pilots are responsible for maintaining a safe distance from other aircraft. This is the "see and be seen" principle otherwise known as VFR or Visual Flight Rules. In this mode of operation, a pilot must keep a continual watch for other aircraft in the sky. When flying above 3,000 feet above ground level (AGL), the pilot must follow VFR cruising altitudes given below (or east/west cruising altitudes).

For jetliners flying inside controlled airspace, pilots are still responsible for maintaining a safe distance from other aircraft. They also must strictly follow IFR or Instrument Flight Rules. In this mode of operation, pilots are flying under reduced visibility and must depend on their instruments for additional guidance and information. Though rules of separation vary depending on the airspace in which a jetliner is flying, in general, air traffic controllers and pilots are required to maintain a horizontal distance of 5 nautical miles between 2 aircraft flying at the same altitude. For altitudes at and below 29,000 feet, vertical separation must be maintained at a minimum 1,000 feet. For altitudes above 29,000 feet vertical separation must be maintained at a minimum of 2,000 feet.



UAV example

Military applications of Unmanned Aerial Vehicles (UAVs) have gotten quite a bit of attention in the media. NASA is investigating other application for UAVs. These include mapping, studies of the Earth's environment, and monitoring forest fires and other natural disasters. However, before such programs can be implemented, systems have to be developed that will allow UAVs and passenger aircraft to safely share the skies. Air traffic controllers routinely work closely with pilots in detecting and avoiding other aircraft. But how will UAVs fit into this system of detection and avoidance?

Researchers at NASA's Dryden Flight Research Center have been testing a collision-avoidance system installed aboard the Proteus, an aircraft that can fly with or without a pilot. Early tests involved the system detecting transponder-equipped aircraft. Later tests had Proteus, equipped with an onboard radar system, sharing airspace with a variety of aircraft, from a hot-air balloon to an F/A-18 jet, and detecting them regardless of whether they were operating transponders. Detection data was relayed from Proteus to controllers on the ground, who were able to make the appropriate decisions and relay instructions back to Proteus.