Definition
A medium-intensity approach lighting system installed in the 3,000 feet of approach area before the runway threshold. It consists of a centerline bar of steady white lights at 100-foot intervals out to 1,400 feet from the threshold, a crossbar of steady white lights at the 1,000-foot point, and five sequenced flashing white lights (Runway Alignment Indicator Lights, or RAIL) positioned beyond the centerline bars from 1,600 feet to 3,000 feet from the threshold. SSALR serves as the standard approach lighting configuration for Category I precision instrument runways at airports where a higher-intensity system such as ALSF-2 is not installed.
Plain English
A line of approach lights leading up to the runway, made up of steady white lights close in and a series of flashing white lights farther out that ripple toward the runway to help the pilot line up during an instrument approach.
Context Anchor
You will see SSALR in approach lighting legends, instrument approach charts, and airport status information, especially when checking whether failed approach lights change the weather required to fly an approach.
Derivation
The name describes the system directly: 'Simplified' and 'Short' indicate it is a shorter, less elaborate version of the full ALSF system; 'Runway Alignment Indicator Lights' refers to the sequenced flashing lights at the far end that visually point the pilot toward the runway centerline.
Why Pilots Care
Allows continuation of an instrument approach when the full approach lighting system is unavailable due to component failures.
Intuition Check
“Simplified” and “short” do not mean casual, optional, or unimportant. Here they mean a specific FAA-recognized runway lighting system with a shorter, reduced layout compared with larger approach lighting systems.
Example Sentence 1
Breaking out at minimums, the pilot first identified the sequenced flashers of the SSALR rippling toward the threshold and continued the approach to landing.
Example Sentence 2
With the primary lighting inoperative, the SSALR still provided enough visual guidance to complete the landing.