When sequencing arrivals on parallel runways, what must be maintained?

• A. Constant altitude separation only.
• B. The same speed for all arrivals.
• C. Adequate lateral and longitudinal spacing to prevent conflicts with departures.
• D. Minimal communication between controllers.

Answer: (C)

When sequencing arrivals on parallel runways, the key requirement is maintaining adequate lateral and longitudinal spacing to prevent conflicts with departures. Lateral spacing keeps inbound aircraft on neighboring approaches from infringing on the other runway’s path or on a departing aircraft, while longitudinal spacing provides a safe distance along the flight path so timing and speed changes don’t bring aircraft too close together or into wake turbulence from a departure. Constant altitude separation by itself isn’t sufficient because aircraft may be at the same altitude yet still have overlapping tracks; equal speed isn’t required and can even hinder efficient sequencing; and minimal communication would increase risk since coordination between controllers and pilots is essential to maintain safe spacing.