UFC 3-535-01
17 November 2005
3-2
APPROACH LIGHT SYSTEM WITH SEQUENCED FLASHING LIGHTS,
(ALSF-2)
3-2.1
Purpose
The ALSF-2 is a high intensity approach light system for operations under Category II or
Category III conditions.
3-2.2
Configuration
The ALSF-2, as shown in Figure 3-5, is configured as an ALSF-1 system modified as
follows:
3-2.2.1
Pre-threshold Bar
The red lights at the pre-threshold bar are removed.
3-2.2.2
Terminating Bar
The red lights at the terminating bar are removed.
3-2.2.3
150 Meter (500 Foot) Bar
A 150 meter (500 foot) bar is added. It consists of two barrettes of aviation white lights,
located symmetrically about and perpendicular to the runway centerline, in line with the
centerline barrette at that station. Each barrette consists of four aviation white lights on
1.5 meter (5 foot) centers, centered in the space between the centerline lights and the
side row lights.
3-2.2.4
Side Row Lights
Side row lights are added to the inner nine lights stations at stations 1+00 through 9+00.
They consist of barrettes containing three aviation red lights, located symmetrically
about and perpendicular to the extended runway centerline at each of the light stations
1+00 through 9+00. the lights in each barrette are on 1.5 meter (5 foot) centers, with
the innermost light spaced 11 meters (36 feet) from the extended runway centerline.
3-2.3
Photometrics
The requirements in paragraph 3-1.4 for ALSF-1 apply.
3-2.4
Aiming Criteria
The aiming criteria as specified in paragraphs 3-1.4.2 through 3-1.4.5 for ALSF-1 apply,
except that the red side row lights be aligned with any existing touchdown lights.
3-2.5
Power Requirements
Provide a main and a standby power system, with automatic transfer time within 1
second of a failure of the system that is in use. See system block diagram at Figure 3-6
and Chapter 12 for additional design guidance.
3-2.6
Control Requirements
The control requirements in paragraph 3-1.6 for ALSF-1 systems apply. Provide a
selector switch in the control tower to switch from ALSF-2 to SSALR.
3-2.7
Monitoring Requirements
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