An approach lighting system (ALS) is a lighting system installed on the approach end of an airport runway and consisting of a series of lightbars, strobe lights, or a combination of the two that extends outward from the runway end. [1]

Section 1. Airport Lighting Aids. Approach Light Systems (ALS) ALS provide the basic means to transition from instrument flight to visual flight for landing. Operational requirements dictate the sophistication and configuration of the approach light system for a particular runway.

The fillowing types of ALS are defined by ICAO: Simple ALS. These are used for non-instrument runways and non-precision approach runways. Precision approach category I lighting system. Precision approach category II lighting system.

These status lists are available for aviation users in order to denote qualified U.S. airports and runways for Category I (CAT I), Category II (CAT II) and Category III (CAT III) Instrument Landing System (ILS) operations.

Jan 12, 2024 · The ALSF-2 is an approach lighting system (ALS), which provides the basic means to transition from instrument flight to visual flight for landing. Operational requirements dictate the sophistication and configuration of the approach light system for a particular runway.

ALSF II (Approach Lighting System with Sequenced Flashing Lights) mode is used on Category II runways during instrument landing approach to align the aircraft with the centerline of the runway and to establish vertical orientation.

Nov 8, 2014 · It is easy to get caught up in the minutia of what makes a Cat I different from a Cat II and so on, but there is only one really basic thing you need to remember about them: The category of ILS approach refers to how low a visibility you can legally fly your airplane down to during the approach.

Apr 27, 2014 · ALSF-1 is less common by far in the U.S., and is the same as the ALSF-2 up to the last 1000 feet. The ALSF-1 loses the red side-row bars and puts a wing-shaped pattern of red lights in the last 200 feet to the threshold. These are the terminating bars in 91.175.

Jun 19, 2006 · ALS are a configuration of signal lights starting at the landing threshold and extending into the approach area a distance of 2400−3000 feet for precision instrument runways and 1400−1500 feet for nonprecision instrument runways.

fixed wing aircraft, to perform a Category I (CAT I) approach below Decision Height (DH), one of the following ten visual references for the intended runway to land are required (see 14 CFR 91.175):