What do L, R, and C mean after a runway number?

• A. Long, Radius, and Center; unrelated.
• B. Left, Center, and Right; misordered.
• C. Left, Right, and Crest; not used.
• D. Left, Right, and Center; parallel runway designators.

Answer: (D)

The letters after a runway number show which of the parallel runways share that same heading. L means Left, R means Right, and C means Center. They’re used to distinguish between multiple runways that run in the same direction.

For example, if an airport has three parallel runways with the same heading, they’ll be designated as 04L, 04C, and 04R. If there are only two, you’d typically see 04L and 04R. The designations are relative to the approach direction—the leftmost is L, the rightmost is R, and the middle is C. This system keeps communication precise when selecting a runway for takeoff or landing.