Sequenced Flashing Lights that are installed only in combination with other light systems of an ALS are identified as ________.

• A. PAPI
• B. VASI
• C. RAIL
• D. MALSR

Answer: (C)

Sequenced flashing lights that appear only as part of the approach lighting system are known as Runway Alignment Indicator Lights. These lights flash in a way that visually guides the pilot to stay on the runway centerline as you approach, and they operate in conjunction with the other ALS components rather than by themselves. They’re not glidepath indicators like PAPI or VASI, which provide vertical guidance, and they’re not the overall name of an approach lighting system like MALSR. The key idea is that these lights serve to show runway alignment and are identified specifically as Runway Alignment Indicator Lights when they’re integrated with other ALS equipment.