Definition
A configuration of approach lights installed on the extended centerline of a runway, beginning at the runway threshold and extending outward into the approach area, used to help pilots transition visually from instrument flight to the runway environment during the final stage of an approach. MALS provides medium-intensity lighting and is one of several standardized approach light system categories recognized by the FAA for use with instrument approach procedures.
Plain English
A row of lights leading up to the runway that helps pilots see and line up with the runway when breaking out of clouds or low visibility on an instrument approach.
Context Anchor
Seen on instrument approach charts and in airport notices about runway lighting or inoperative approach components.
Derivation
Medium refers to the brightness level (between low and high intensity systems). Approach refers to the final segment of flight leading to the runway. Lighting System describes the coordinated array of lights working together as one visual aid.
Why Pilots Care
Ensures pilots have adequate visual references for safe landing in marginal weather.
Intuition Check
MALS does not mean the runway edge lights. It refers to the approach lights before the runway that help guide the pilot toward the runway threshold.
Example Sentence 1
The approach chart showed MALS in service, so the crew briefed the standard visibility minimums for the ILS.
Example Sentence 2
Pilots use the MALS lights to confirm runway alignment during the transition from instrument to visual flight.