UFC 3-535-01
17 November 2005
at the approach end of system. The plane may have irregularities. The width varies
according to the lighting system.
Decision Height--The height above the highest elevation in the touchdown zone,
specified for a glide slope approach at which a missed approach procedure must be
initiated if the required reference has not been established.
Displaced Threshold Area--An area of full strength pavement on the approach slope
of the threshold intended for use during takeoff or during rollout after landing from the
opposite direction.
Footcandle--One lumen per square foot (10.8 lux).
Frangible Support--A support for elevated fixtures or other devices composed of a
supporting element with a fracture mechanism at its base. It is designed to present a
minimum of mass and to break at the base when impacted.
Instrument Runway--A runway served by non-visual aids giving directional guidance
adequate for a straight in approach. It may be further classified as:
Precision Approach Runway, Category I--A runway served by an Instrument
Landing System (ILS), Microwave Landing System (MLS), or precision Approach
Radar (PAR) and visual aids intend for operations down to 60 meters (200 feet)
decision height, and down to a runway visual range (RVR) on the order of 720
meters (2,400 feet). These criteria also apply to visual lighting aids supporting Air
Force precision approach radar approaches down to a decision height of 30 meters
(100 feet) and an RVR on the order of 360 meters (1,200 feet).
Precision Approach Runway, Category II--A runway served by ILS or MLS and
visual aids intended for operations down to 30 meters (100 feet) decision height and
down to an RVR on the order of 360 meters (1,200 feet).
Precision Approach Runway, Category III--A runway served by
ILS or MLS (no
decision height being applicable) and:
Category IIIa: By visual aids intended for operations down to
an RVR on the
order of 210 meters (700 feet).
Category IIIb: By visual aids intended for operations down to
an RVR on the
order of 45 meters (150 feet).
Category IIIc: Intended for operations without reliance on
external visual
reference. (The RVR is 0).
Light Bar--A set of lights arranged in a row perpendicular to the light system
centerline, also known as a barrette.
Lux--One lumen per square meter (1/10 (0.0929)) footcandle).
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