Pilot-controlled lighting (PCL), also known as aircraft radio control of aerodrome lighting (ARCAL) or pilot-activated lighting (PAL), is a system that allows aircraft pilots to control the lighting of an airport or airfield's
approach lights,
runway edge lights
Runway edge lighting 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:
* High intensity runway l ...
, and
taxiway
A taxiway is a path for aircraft at an airport connecting runways with aprons, hangars, terminals and other facilities. They mostly have a hard surface such as asphalt or concrete, although smaller general aviation airports sometimes use gravel ...
s via radio.
Technical details
At some airfields, the
airport/aerodrome beacon may also be ARCAL controlled. ARCAL is most common at
non-towered airport
In aviation, a non-towered airport is an airport without a control tower, or air traffic control (ATC) unit. The vast majority of the world's airports are non-towered. In the United States, there are close to 20,000 non-towered airports compared ...
s 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
A UNICOM (universal communications) station is an air-ground communication facility operated by a non-air traffic control private agency to provide advisory service at uncontrolled aerodromes and airports and to provide various non-flight services ...
/
CTAF
Common traffic advisory frequency (CTAF) is the name given to the VHF radio frequency used for air-to-air communication at United States, Canadian and Australian non-towered airports.
Many towered airports close their towers overnight, keeping ...
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 the latter is runway 18/36 at the
airport in Sydney, Nova Scotia. 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 types of ARCAL systems — type J and type K.
Type J systems are activated by keying the microphone five times within five seconds, while type K is initially activated by clicking seven times within five seconds. Once activated, the intensity of type K systems may then be turned to low, medium, or high intensity settings by keying the microphone three, five, or seven times within five seconds, respectively. If runway identification lights are also controlled by type K ARCAL, they may be turned off by keying the microphone three 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 fifteen-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. When in operation, the receiver awaits a
squelch break on the tuned VHF frequency and begins counting "clicks" in a five-second period to determine pilot intent. The pilot commanded output is held by the controller for a predetermined time interval (
Federal Aviation Administration
The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic m ...
standard is 15 minutes) that is generally adjustable. The five-second click count period begins upon receipt of the first squelch break and the control sequence will respond to the click counts from three, five, seven and stop. As an example, cycling the microphone button rapidly 15 times in five seconds will command "three, five, seven". Similarly, slowly clicking seven times may result in the five-second timing period expiring prior to getting to the seventh input click.
In the United States, pilot-controlled lighting is governed by
Federal Communications Commission
The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdiction ...
Rule 87.187y. This section also lists the radio frequencies that are allowed to control runway lights via pilot-controlled lighting.
See also
*
Approach lighting system (ALS)
*
Precision approach path indicator
A precision approach path indicator (PAPI) is a visual aid that provides guidance information to help a pilot to acquire and maintain the correct approach (in the vertical plane) to an airport or an aerodrome. It is generally located on the left- ...
(PAPI)
*
Runway edge lights
Runway edge lighting 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:
* High intensity runway l ...
(HIRL, MIRL, LIRL)
*
Runway end identifier lights
Runway end identifier lights (REIL) (ICAO identifies these as Runway Threshold Identification Lights) are installed at many airports to provide rapid and positive identification of the approach end of a particular runway. The system consists of a ...
(REIL)
*
Visual approach slope indicator
The visual approach slope indicator (VASI) is a system of lights on the side of an airport runway threshold that provides visual descent guidance information during approach. These lights may be visible from up to during the day and up to or mo ...
(VASI)
References
{{reflist
External links
Pilot's Handbook of Aeronautical Knowledge
Airport lighting