Pilot Controlled Lighting
Encyclopedia
Pilot Controlled Lighting (PCL), also known as Aircraft Radio Control of Aerodrome Lighting (ARCAL) or Pilot Activated Lighting (PAL), is a system which allows aircraft pilots to control the lighting of an airport or airfield's approach lights
, runway
edge lights
, and taxiway
s via radio
. At some airfields, the aerodrome beacon
may also be ARCAL controlled. ARCAL is most common at non-towered
or little-used airfields where it is neither economical to light the runways all night, nor to provide staff to turn the runway lighting on and off. It enables pilots to control the lighting only when required, saving electricity
and reducing light pollution
.
The ARCAL frequency for most aerodromes is usually the same as the UNICOM
/CTAF frequency, although in some rare cases, a second ARCAL frequency may be designated to control the lighting for a second runway separately (an example of this is runway 01/19 at the airport in Sydney, NS). To activate the lights, the pilot clicks the radio transmit switch on the ARCAL frequency a certain number of times within a specified number of seconds. There are two type of ARCAL systems, type J and type K. Type J systems are activated by keying the microphone 5 times within 5 seconds, while type K is initially activated by clicking 7 times within 5 seconds. Once activated, the intensity of type K systems may then be turned to low, medium, or high intensity settings by keying the microphone 3, 5, or 7 times within 5 seconds respectively. If runway identification lights are also controlled by type K ARCAL, they may be turned off by keying the microphone 3 times.
When either type of system is activated, a 15-minute countdown starts, after which the lights turn off. While the lights are on, whenever a lighting command is issued, whether it changes the lighting intensity or not, the 15-minute countdown is reset. At some airfields, the lights may flash once to warn pilots that the lights are about to go off, before turning off two minutes later.
When using ARCAL, it is strongly recommended that aircraft on final approach to the airfield issue a fresh lighting command, even if the lights are already on (especially if the lights were activated by another aircraft). This is so that the lighting does not turn off at a critical moment (such as when crossing the runway threshold).
Approach Lighting System
An approach lighting system, or 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...
, runway
Runway
According to ICAO a runway is a "defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft." Runways may be a man-made surface or a natural surface .- Orientation and dimensions :Runways are named by a number between 01 and 36, which is generally one tenth...
edge lights
Runway Edge Lights
Runway Edge Lights are used to outline the edges of runways during periods of darkness or restricted visibility conditions. These light systems are classified according to the intensity they are capable of producing:...
, and taxiway
Taxiway
A taxiway is a path on an airport connecting runways with ramps, hangars, terminals and other facilities. They mostly have hard surface such as asphalt or concrete, although smaller airports sometimes use gravel or grass....
s via radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
. At some airfields, the aerodrome beacon
Aerodrome beacon
An aerodrome beacon or rotating beacon is a beacon installed at an airport or aerodrome to indicate its location to aircraft pilots at night....
may also be ARCAL controlled. ARCAL is most common at non-towered
Non-towered airport
A non-towered airport, sometimes referred to as an uncontrolled airport, is an airport with no operating tower, or air traffic control unit...
or little-used airfields where it is neither economical to light the runways all night, nor to provide staff to turn the runway lighting on and off. It enables pilots to control the lighting only when required, saving electricity
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
and reducing light pollution
Light pollution
Light pollution, also known as photopollution or luminous pollution, is excessive or obtrusive artificial light.The International Dark-Sky Association defines light pollution as:...
.
The ARCAL frequency for most aerodromes is usually the same as the UNICOM
Unicom
Unicom may refer to:* UNiCOM, or [UNiCOM] photo, UK based News & Sports Photography Agency* UNICOM, or Universal Communications, air-ground communication facility*China Unicom, telecommunication operator in China...
/CTAF frequency, although in some rare cases, a second ARCAL frequency may be designated to control the lighting for a second runway separately (an example of this is runway 01/19 at the airport in Sydney, NS). To activate the lights, the pilot clicks the radio transmit switch on the ARCAL frequency a certain number of times within a specified number of seconds. There are two type of ARCAL systems, type J and type K. Type J systems are activated by keying the microphone 5 times within 5 seconds, while type K is initially activated by clicking 7 times within 5 seconds. Once activated, the intensity of type K systems may then be turned to low, medium, or high intensity settings by keying the microphone 3, 5, or 7 times within 5 seconds respectively. If runway identification lights are also controlled by type K ARCAL, they may be turned off by keying the microphone 3 times.
When either type of system is activated, a 15-minute countdown starts, after which the lights turn off. While the lights are on, whenever a lighting command is issued, whether it changes the lighting intensity or not, the 15-minute countdown is reset. At some airfields, the lights may flash once to warn pilots that the lights are about to go off, before turning off two minutes later.
When using ARCAL, it is strongly recommended that aircraft on final approach to the airfield issue a fresh lighting command, even if the lights are already on (especially if the lights were activated by another aircraft). This is so that the lighting does not turn off at a critical moment (such as when crossing the runway threshold).
See also
- Visual Approach Slope IndicatorVisual Approach Slope IndicatorThe visual approach slope indicator is a system of lights on the side of an airport runway threshold that provides visual descent guidance information during the approach to a runway...
(VASI) - Precision Approach Path IndicatorPrecision Approach Path IndicatorPrecision approach path Indicator is a visual aid that provides guidance information to help a pilot acquire and maintain the correct approach to an aerodrome or an airport. It is generally located beside the runway approximately 300 metres beyond the landing threshold of the runway...
(PAPI) - Runway End Identifier Lights (REIL)
- Runway Edge LightsRunway Edge LightsRunway Edge Lights are used to outline the edges of runways during periods of darkness or restricted visibility conditions. These light systems are classified according to the intensity they are capable of producing:...
(HIRL, MIRL, LIRL) - Approach Lighting SystemApproach Lighting SystemAn approach lighting system, or 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...
(ALS)