How does the ALCMS control the runway?
One operator action reaches every runway lighting circuit through its own CCR — and each circuit reports its own status back.
A runway is lit by several separate circuits — typically approach, threshold, edge, touchdown zone, centreline and runway end — each fed by its own CCR. The ALCMS-to-runway link lets the operator treat the runway as one object: select the runway in use, set the brightness for the conditions, and the ALCMS sends the matching commands to every relevant CCR.
What comes back is status for each circuit: state, step, current and faults. That keeps a single failed circuit visible instead of hidden inside a runway-wide indication, and the other circuits keep their own status. Which circuits are used and at what brightness is set by airport procedure, not by the ALCMS alone.
- Select. The operator chooses the runway and its lighting configuration.
- Command. The ALCMS sends on/off and step commands to each circuit’s CCR.
- Light. Each CCR sets its current and the runway lights respond.
- Verify. Each circuit reports back and any fault is shown against that circuit.
Frequently Asked Questions
Q1What is the ALCMS-to-runway link?
The control and monitoring path from the ALCMS to the lighting circuits of a runway. The operator acts on the runway as a whole, and the ALCMS passes the commands to the CCR of each runway circuit.
Q2Which runway circuits does the ALCMS control?
Typically the approach, threshold, runway edge, touchdown zone, centreline and runway end lighting, each on its own circuit. Exactly which circuits exist depends on the runway category and the airport design.
Q3Why are there several circuits and not one?
Different lights have different roles and need separate control and protection. Keeping them on separate circuits also means a fault on one does not take out the rest of the runway lighting. On precision-approach runways the circuits are also commonly interleaved, so a single circuit failure leaves a pattern of working lights rather than a dark section.
Q4Who decides which circuits are on and at what brightness?
The operator selects them according to the runway in use, the visibility and the airport procedures. The ALCMS carries out that selection by commanding the relevant CCRs.
Q5How is runway status shown?
Per circuit. Each CCR reports its state, step, current and faults, so the operator sees which part of the runway lighting is healthy and which is not, rather than a single runway-wide indication.
Q6What happens if one runway circuit fails?
The ALCMS shows the affected circuit as faulty while the others keep their status. The operator and maintenance staff then act on that specific circuit under the airport procedures.
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