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.
- Spend 70% of pilot time scanning the skies using a series of short, regularly spaced eye movements in 10° sections alternately looking both near and far, horizontally and vertically.
- If there is no apparent motion between the aircraft you are piloting and another aircraft, then both are probably on a collision course.
- Be aware of your aircraft's blind spots.
- Before beginning a maneuver, make clearing turns while carefully scanning the area for other aircraft.
- When faced with an aircraft approaching head-on, both aircraft are required to alter the course to the right.
- When overtaking another aircraft flying in the same direction and on the same course, the aircraft being overtaken has the right-of-way, therefore pass well clear of it on the right.
- When two aircraft are converging or approaching from the side, the aircraft to the left must give way to the aircraft on the right.
- A general right-of-way rule states that the least maneuverable aircraft has the right-of-way.
- Over congested areas (city or metropolitan area), aircraft are required to fly 1,000 feet above any obstruction (tall building, for example) within a horizontal radius of 2,000 feet of that aircraft.
- Over uncongested areas (rural land, not open water), aircraft are required to fly at least 500 feet above the surface.
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).
- Flying a magnetic course of 0° - 179°, fly at odd thousands plus 500 feet. For example, 3,500; 5,500; 7,500.
- Flying a magnetic course of 18° - 359°, fly at even thousands plus 500 feet. For example, 4,500; 6,500; 8,500.
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.
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.