Definition
A configuration of approach lights installed at the end of a runway to provide visual guidance to pilots transitioning from instrument flight to visual flight on landing. MALS uses medium-brightness steady-burning lights arranged along the extended runway centerline to help the pilot identify the runway and align the aircraft during the final stages of an instrument approach.
Plain English
A row of medium-brightness lights leading up to the runway that helps a pilot see and line up with the runway when breaking out of cloud or low visibility on an instrument approach.
Context Anchor
You may see MALS listed on an instrument approach chart, in approach minimums, or in a notice that says part of the airport lighting is not working.
Derivation
‘Approach lighting system’ describes its purpose — lights that guide the approach to the runway. ‘Medium intensity’ distinguishes it from higher-intensity systems (like ALSF-1 or ALSF-2) used at busier or lower-minimum runways. The medium brightness is sufficient for the lower category of approaches MALS supports.
Why Pilots Care
Indicates available visual guidance that can lower landing minimums; when inoperative, approach minimums must be raised per the inoperative components table.
Grounding Statement
MALS gives the pilot a lighted path toward the runway during the final part of an approach.
Intuition Check
“Medium intensity” does not mean the system is of medium importance. It means the lights are in a specific FAA brightness class, lower than high-intensity approach lights but still designed to guide landing aircraft.
Example Sentence 1
After breaking out of the clouds at minimums, the pilot picked up the MALS lights and used them to align with the runway centerline.
Example Sentence 2
With MALS reported out of service, the crew consulted the inoperative components table and added 200 feet to the MDA.