The minimum standard lateral separation of departures under instrument conditions is based on which equipment?

• A. Doppler radar
• B. Tactical Air Navigation
• C. Instrument Landing System
• D. VOR

Answer: (B)

When talking about keeping aircraft apart laterally in instrument conditions, the reference used to define and enforce that spacing is the navigation aid that provides reliable lateral positioning. TACAN gives both azimuth (bearing) and range (DME) to a station, so controllers can determine an aircraft’s precise position relative to a defined departure path and maintain the required side-by-side separation between multiple departures. This combination of bearing and distance makes TACAN the standard basis for establishing standard lateral separation in this environment.

Doppler radar is mainly a surveillance tool for tracking speed and position, not the formal basis for separation minima. VOR is a common navigation aid, but in carrier operations the TACAN’s bearing-and-range capability is the authoritative reference for lateral separation. Instrument Landing System is designed for precision approaches, not for determining departure separations.