Operate runway edge lights between sunset and sunrise for arriving IFR aircraft ___.

• A. before the aircraft is estimated over the Outer Marker (OM)
• B. before the aircraft begins final approach
• C. when you receive the inbound
• D. when requested by the pilot

Answer: (B)

When you’re lighting the runway for arriving IFR aircraft during night, you want the runway environment clearly defined as the aircraft transitions from instrument guidance to the approach. Turning on the runway edge lights before the aircraft begins final approach gives pilots reliable visual cues for the runway edges and threshold as they setup for the glide slope. This helps with depth perception, alignment, and situational awareness in low-light conditions, reducing the chance of misidentifying the runway or drifting off course.

Waiting until the aircraft is established on an inbound or waiting for the pilot’s request can leave the pilot without essential lighting during the critical final approach phase, which is why activating the lights in advance is the standard practice.