AAAE ACE Operations Module 2 Practice Exam 2026 – Your All-in-One Guide to Mastering the Operations Certification!

REILs (Runway End Identifier Lights) are two synchronized flashing lights placed near the threshold to give pilots a quick, unmistakable cue of the runway end on approach. To ensure these lights are clearly visible and properly aligned with the threshold without being obstructed or misinterpreted, they are installed within 40 feet of the runway edge. This spacing keeps the lights effectively in the pilot’s line of sight during the final approach and helps identify the threshold reliably, especially in low-visibility conditions. Distances greater than 40 feet can place the lights too far from the edge to serve their identification purpose, while too-small a distance can create mounting or clearance issues. So the standard proximity is within 40 feet of the runway edge.