Runway Threshold Lighting (RTILS) versus REIL: which statement is true?

Runway Threshold Lighting (RTILS) versus REIL: which statement is true?

• A. RTILS are the same as REIL in function and placement.
• B. RTILS are a separate system that provides threshold lighting with two synchronized flashing lights at the threshold facing the approach area.
• C. RTILS operate only at night.
• D. RTILS are located on the runway centerline.

Answer: (B)

Threshold lighting systems and REIL are separate lighting setups designed to help identify the threshold, but they are not the same thing. The statement describes RTILS as a distinct system that provides threshold lighting with two synchronized flashing lights placed at the threshold facing the approach area. This captures the idea that RTILS are specifically positioned to mark the threshold for approaching aircraft, using a pair of lights that flash in unison to draw the pilot’s attention to the threshold location. The other options either imply RTILS are identical to REIL, or claim they operate only at night, or that they’re located on the runway centerline. Those descriptions don’t match how RTILS are implemented.

Threshold lighting systems and REIL are separate lighting setups designed to help identify the threshold, but they are not the same thing. The statement describes RTILS as a distinct system that provides threshold lighting with two synchronized flashing lights placed at the threshold facing the approach area. This captures the idea that RTILS are specifically positioned to mark the threshold for approaching aircraft, using a pair of lights that flash in unison to draw the pilot’s attention to the threshold location.

The other options either imply RTILS are identical to REIL, or claim they operate only at night, or that they’re located on the runway centerline. Those descriptions don’t match how RTILS are implemented.