Phases of Flight

Aircraft flying in the NAS can be in one of five phases of flight, as defined in the Federal Radionavigation Plan:

• Oceanic En Route: This phase covers operations over ocean areas generally characterized by low traffic density and no independent surveillance coverage.
• Domestic En Route: Operations in this phase are typically characterized by moderate to high traffic densities. This necessitates narrower route widths than in the oceanic en route phase. Independent surveillance is generally available to assist in ground monitoring of aircraft position.
• Terminal Area: Operation in the terminal area is typically characterized by moderate to high traffic densities, converging routes, and transitions in flight altitudes. Narrow route widths are required. Independent surveillance is generally available to assist in ground monitoring of aircraft position.
• Nonprecision Approach: Nonprecision approach aids provide a landing aircraft with horizontal position information (2-dimensional approaches).
• Precision Approach and Landing: Precision approach aids provide landing aircraft with vertical and horizontal guidance and positioning information (3-dimensional approaches).

[close]