3-4-3. VISUAL APPROACH SLOPE INDICATORS (VASI)

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  • 3-4-3. VISUAL APPROACH SLOPE INDICATORS (VASI)

    VASI systems with remote on-off switching must be operated when they serve the runway in use and where intensities are controlled in accordance with TBL 3-4-2 and TBL 3-4-3 except:

    1. As required by facility directives to meet local conditions.
    2. As required by the pilot.
    TBL 3-4-2 VASI Intensity Setting-Two Step System
    Step Period/Condition
    High Day - Sunrise to sunset.
    Low Night - Sunset to sunrise.
    TBL 3-4-3 VASI Intensity Setting-Three Step System
    Step Period/Condition
    High Day - Sunrise to sunset.
    Medium Twilight - From sunset to 30 minutes after sunset and from 30 minutes before sunrise to sunrise,* and during twilight in Alaska.
    Low Night - Sunset to sunrise.
    *During a 1 year period, twilight may vary 26 to 43 minutes between 25 and 49N latitude.

    NOTE: The basic FAA standard for VASI systems permits independent operation by means of photoelectric device. This system has no on-off control feature and is intended for continuous operation. Other VASI systems in use include those that are operated remotely from the control tower. These systems may consist of either a photoelectric intensity control with only an on-off switch, a two step intensity system, or a three step intensity system.

    • REFERENCE
    • FAA Order JO 7210.3, Para 10-6-5, Visual Approach Slope Indicator (VASI) Systems.
    • FAA Order 6850.2, Visual Guidance Lighting Systems.
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