Definition
Two standard approach lighting systems installed at the approach end of an instrument runway to help the pilot transition from instrument flight to a visual landing. SSALR is a simplified, high-intensity system used primarily on Category I precision runways at larger airports, consisting of a centerline bar of steady-burning lights extending 2,400 feet from the runway threshold, a 1,000-foot crossbar, and a sequence of flashing strobe lights (Runway Alignment Indicator Lights, or RAILs) along the outer portion. MALSR is a medium-intensity version of the same general layout, extending 2,400 feet from the threshold with a 1,000-foot crossbar and RAIL strobes on the outer 1,500 feet, and is the most common approach lighting system on Category I instrument runways in the United States. Both systems provide visual cues for runway alignment, distance to the threshold, and roll guidance during the final segment of an instrument approach.
Plain English
Two types of runway approach lights that guide a pilot to the runway at the end of an instrument approach. Both run about 2,400 feet out from the runway and include a row of flashing strobes that 'walk' toward the runway to show the pilot where to line up. SSALR is the brighter version used at busier airports; MALSR is the more common medium-brightness version.
Context Anchor
Seen on instrument approach charts, airport lighting information, and runway lighting diagrams for approaches flown in reduced visibility.
Derivation
The names are descriptive abbreviations. 'Simplified' and 'Medium-intensity' describe the brightness and complexity of the system. 'Approach Lighting System' refers to the lights leading up to the runway. 'Runway Alignment Indicator Lights' (RAIL) are the sequenced flashing strobes added on the outer end to draw the pilot's eye toward the runway centerline.
Why Pilots Care
These systems give pilots positive visual confirmation of runway alignment at decision height, reducing the risk of misalignment or controlled flight into terrain during low-visibility landings.
Intuition Check
SSALR/MALSR is not one combined lighting system. The slash means the chart or figure is grouping two similar approach lighting systems together.
Example Sentence 1
The approach plate showed MALSR lighting, so the pilot knew to look for the sequenced flashers leading to the runway as they approached minimums.
Example Sentence 2
SSALR lighting was noted on the approach chart as the visual aid available for the ILS to runway 27.