Which statement correctly describes vertical and lateral separation?

• A. Vertical separation is the horizontal distance between aircraft.
• B. Vertical separation is the altitude difference; lateral separation is the horizontal distance between aircraft.
• C. Vertical separation is time difference; lateral separation is distance difference.
• D. Vertical separation and lateral separation are the same.

Answer: (B)

The idea being tested is how separation between aircraft is defined in air traffic control. Vertical separation refers to the difference in altitude between two aircraft, i.e., the vertical distance they occupy in flight levels or feet. Lateral separation refers to the horizontal distance between them, measured in nautical miles on the map view.

This is why the correct statement is best: it accurately pairs vertical separation with altitude difference and lateral separation with horizontal distance. The other descriptions mix up the concepts—vertical separation is not a horizontal distance, not a time difference, and the two types are not the same—so they don’t reflect how aircraft are kept apart safely.