Overview
Approach Light Systems (ALS) are deisgned to provide the basic means to transition from instrument flight to visual flight for landing. The type of instrument approach, among other factors, determines the specific type of ALS installed for a given runway. An ALS typically begins at the landing threshold and extends into the approach area between 1,500 feet and 3,000 feet. Many ALS also have a sequenced flasher, also known as the "rabbit" to assist pilots in identifying the runway.
Examples
The table contains some of the most commonly used approach lighting systems.
| System | Definition | Use |
|---|---|---|
| MALS | Medium Intensity Approach Lighting System | An economy type system for non precision approaches. |
| MALSF | Medium Intensity Approach Lighting System with Sequenced Flashers | Same as MALS, but equipped with three sequenced flashers at locations where approach area identification problems exist. |
| MALSR | Medium Intensity Approach Lighting System with Runway Alignment Indicator Lights | An economy type system used as the FAA standard for category I precision runways. |
| ALSF-2 | High Intensity ALS with Sequenced Flashers | Used on category II and III precision approach runways. |
| SSALR | Simplified Short Approach Lighting System with Runway Alignment Indicator Lights | Used the same as MALSR. Generally, the SSALR is not to be installed as a new system. This configuration is used when category I conditions exist on category II designated runways with a dual mode approach lighting system. (ALSF-2/SSALR) |
