Learn how to use pilot-controlled runway lighting: find the frequency, send 3/5/7 mic clicks, choose intensity and fix common PCL failures.
To use pilot-controlled runway lighting (PCL), tune the published airport-lighting frequency and press the push-to-talk switch the specified number of times within the stated interval. In the United States, three, five and seven clicks commonly select low, medium and high intensity, but always verify the airport’s published procedure.
In real-world aviation, PCL may also be described as pilot-controlled airport lighting, PAL or ARCAL, depending on the country. The operating sequence is not universal, so do not carry the familiar US three-five-seven pattern into another jurisdiction without checking.
Where is the PCL frequency published?
The controlling frequency and any special instructions are published in the airport’s official aeronautical data. Check the airport entry, AIP or Chart Supplement, relevant NOTAMs and any lighting note on the approach plate; our guide to finding lighting information on an instrument approach chart explains where those details usually appear.
PCL may use the CTAF, UNICOM or a dedicated lighting frequency. At a towered airport, a different frequency or procedure may apply after the tower closes. Never assume the traffic frequency also controls the lights simply because that arrangement is common.
How do I activate pilot-controlled runway lights?
Activate PCL with distinct push-to-talk transmissions on the published frequency, early enough to confirm that the runway has illuminated.
- Review the airport entry. Confirm the frequency, click sequence, operating hours, controlled runway and any linked approach or taxiway lights.
- Tune the transmitting radio. Put the frequency in the active COM window and select the correct radio on the audio panel. A standby frequency cannot control the lights.
- Wait for a clear frequency. Another transmission can interrupt the sequence and prevent the receiver from counting it correctly.
- Key and release the push-to-talk switch. Each complete press-and-release cycle is one click. On a typical US installation, complete all three, five or seven clicks within five seconds. Do not hold the transmitter open or make a voice call in place of the sequence.
- Confirm the lights visually. If high intensity produces glare in mist, rain or a wet windscreen, select medium or low once the runway is positively identified.
- Allow for the timer. If the lights could expire before landing or taxiing clear, repeat the published sequence before the workload becomes high.
The PTT switch must key the actual radio transmitter. Pressing an intercom switch, changing the audio-panel microphone selection or operating the transponder IDENT button does nothing.
What do three, five and seven microphone clicks mean?
At many US airports, three, five and seven clicks request progressively brighter lighting, but the available levels depend on the installed equipment.
| Clicks | Usual US selection | Typical use |
|---|---|---|
| 3 | Low intensity | Reducing glare after acquiring the runway |
| 5 | Medium intensity | Normal night visual reference in clear conditions |
| 7 | High intensity | Initial activation or maximum visibility |
A low-intensity runway-light system may have only one brightness, so every recognised sequence simply switches it on. Approach lights, REILs, taxiway lights and visual glidepath indicators may be linked to the controller, independently operated or unavailable. Our explanation of approach-light configurations and intensity settings covers those systems separately.
How long do PCL lights stay on?
Many US pilot-controlled lighting systems remain active for about 15 minutes after a recognised sequence, although local timing can differ. Sending another valid sequence commonly restarts the timer and selects the requested intensity.
Activate the system before becoming dependent on it, but not so early that the timer is likely to expire on final. Remember that the controller is shared: another pilot may activate the lights or change their intensity.
Why did the runway lights not switch on?
Most failed PCL activations result from the wrong frequency, an incomplete click sequence or operating outside the system’s published conditions.
- Wrong COM selected: verify the active frequency, audio-panel transmitter selection and radio’s transmit indication.
- Clicks too fast or too slow: use clear, separate press-and-release cycles while keeping the complete sequence inside the specified interval.
- Frequency occupied: pause until traffic calls have finished, then send the entire sequence again.
- Outside radio range: try again closer to the airport, while retaining safe terrain clearance and an escape plan.
- System not available: PCL may operate only at night, during unattended hours or when enabled by an airport schedule or light sensor.
- Lighting unserviceable: check NOTAMs and treat persistent failure as an equipment outage rather than circling low while troubleshooting.
- Wrong expectation: the runway edge lights may respond while the PAPI, approach lights or taxiway lights remain independent.
If a careful retry using the published procedure fails, apply the relevant night-flight rules and instrument minima, then use a suitable alternate if the required lighting is unavailable.
Does activating PCL mean the runway is clear?
No. PCL only commands the lighting controller; it does not provide a landing clearance or confirm that the runway is open, unobstructed or suitable for your aircraft.
Continue normal radio calls and visual scanning, verify runway alignment and distinguish the runway edges, threshold, centreline and taxiway lighting correctly. Our guide to interpreting runway-light colours and visual cues explains what each lighting element tells the pilot once the system is on.