Definition
A medium-intensity airport approach lighting system installed at the approach end of an instrument runway. It consists of a centerline of steady white lights extending outward from the runway threshold for about 1,400 feet, with a row of five high-intensity sequenced flashing lights (Runway Alignment Indicator Lights, or RAIL) extending the system out to a total length of about 3,000 feet. The flashing lights fire in rapid succession toward the runway, giving the appearance of a ball of light running down the centerline to guide the pilot to the threshold.
Plain English
A line of lights on the ground leading up to the runway. The lights closest to the runway stay on steadily, and the ones farther out flash one after another toward the runway, like an arrow pointing the way in.
Context Anchor
You encounter this term on airport lighting information, instrument approach charts, and runway environment descriptions.
Derivation
The name describes the system literally. 'Simplified' and 'Short' mean it is a smaller, less elaborate version than the full-length approach light systems used at major airports. 'Runway Alignment Indicator Lights' refers to the sequenced flashing lights that show the pilot the line into the runway. Knowing this helps the pilot expect a shorter installation with the distinctive 'running rabbit' flashing lead-in.
Why Pilots Care
Provides essential visual cues for runway alignment in reduced visibility, reducing the chance of misalignment during final approach.
Grounding Statement
Think of it as a lighted guide leading the pilot’s eyes toward the runway centerline and threshold during the last part of the approach.
Intuition Check
“Simplified” and “short” do not mean informal or less important. Here they mean the lighting layout is less extensive than some larger approach light systems, while still serving a precise runway-alignment purpose.
Example Sentence 1
The approach plate showed an SSALR installed on Runway 27, so we knew to look for the flashing lead-in lights as we descended through the cloud base.
Example Sentence 2
Airports with the Simplified Short Approach Light System With Runway Alignment Indicator Lights give pilots extra help lining up the aircraft during night or low-visibility landings.