Procedural Control

General

The general principles of air traffic control are the same regardless of whether procedural or surveillance methods are used (i.e. the controller monitors the traffic situations, detects and solves conflicts by providing separation, and ensures orderly flow of the air traffic). The difference lies in the way situational awareness is built and updated (by pilot reports, estimates and visual observation), the separation minima themselves (as described in ICAO Doc 4444, Chapter 5) and the support tools (flight strips instead of a situation display).

Typical Applications

Typical applications of procedural control include:

• In airspace where surveillance cover is not available (e.g. oceanic airspace or sparsely populated areas)
• In terminal movement areas (TMAs) if the traffic levels are such that they do not warrant the installation and maintenance of a surveillance system
• In aerodrome control zones (CTRs), especially if the traffic density is relatively low and the aerodrome layout is not complex (e.g. only one runway, one apron and a few taxiways)
• Backup solution in case of complete failure of all surveillance-based systems

Separation

Initial Separation of Successive Departing Aircraft

Initial Separation of Departing and Arriving Aircraft

Longitudinal Separation

Lateral Separation

Vertical Separation

 

Procedures

 

Timed Approaches