ALCMS — Airfield Lighting Control & Monitoring System
The Airfield Lighting Control and Monitoring System (ALCMS) is the control and monitoring layer of an Airfield Ground Lighting system. It gives airport operators the interface to control lighting, monitor equipment status, receive fault information, manage configurations, observe alarms and maintain an operational record — answering two critical questions: what is commanded, and what is the actual condition of the system.
What Is ALCMS?
ALCMS stands for Airfield Lighting Control and Monitoring System — a centralized system used to control, supervise and monitor airport lighting equipment and circuits.
An ALCMS does not replace the field lighting system. It connects the operational control environment with equipment such as Constant Current Regulators, lighting circuits, runway lights, taxiway lights, approach lighting, PAPI, illuminated signs and other airfield visual aids. The exact architecture depends on airport requirements, lighting system design, control philosophy, equipment manufacturers and project specifications.
Control Functions
ON/OFF control, intensity control, circuit selection and CCR control across the airport's lighting systems.
Monitoring Functions
Equipment status, fault indication, alarm generation, event logging and historical monitoring.
Operator Functions
Visualization, remote and local control integration, and communication with field equipment.
Why ALCMS Is Important
Modern airports contain a large number of lighting circuits and visual aids. Manually controlling every system from individual equipment locations would be inefficient and difficult to manage. ALCMS provides a centralized operational interface that helps operators select systems, adjust intensity, observe status, identify faults, respond to alarms, verify commands, monitor availability and record events.
The objective is not simply to turn lights ON. The objective is to provide controlled, visible and traceable management of the AGL system.
ALCMS in the Complete AGL System
ALCMS sits above the field equipment and provides the control and monitoring interface. Control and monitoring are two distinct, complementary chains.
ALCMS Architecture — The Five Layers
A typical ALCMS can be understood as five connected layers, each with its own equipment and engineering considerations.
Operator Layer
- Operator workstation
- HMI
- Display
- Keyboard & control interface
- Alarm interface
Control Layer
- PLC
- RTU
- Control processors
- I/O modules
- Control logic
Communication Layer
- Ethernet
- Fibre optic network
- Serial communication
- Industrial communication protocols
- Field communication networks
Equipment Layer
- CCRs
- CCR monitors
- Control panels
- Field controllers
- Monitoring devices
- Lighting equipment interfaces
Field Layer
- Series circuits
- Isolation transformers
- Light fixtures
- PAPI, signs, stop bars
- Runway guard lights & other visual aids
Central Control System
The main interface between airport operations and the lighting system — main server, operator workstation, HMI, control software, database, communication interface, alarm system, event logging system and network equipment. It should provide clear information about the current state of the lighting system.
Commands travel down through each layer; status and fault information travels back up — a break at any layer affects everything below it
Operator Workstation & HMI Design
The operator workstation is the primary human interface to the ALCMS. The Human Machine Interface (HMI) should present the AGL system in a logical, understandable manner — avoiding unnecessarily complicated screens.
Operator Capabilities
- Select lighting circuits
- Change intensity
- View system status
- Acknowledge alarms
- View equipment faults
- Review events
- Access system diagrams
- Monitor communication status
A Good HMI Provides
- Clear equipment identification
- Circuit & intensity status
- Alarm & communication status
- Fault information
- Control confirmation
- Time & event information
Ultimately, the operator should always be able to determine: What is ON? What is OFF? What is commanded? What has failed? Where is the problem?
The AGL Mimic Diagram
The mimic diagram provides a graphical representation of the airfield lighting system — runways, taxiways, lighting circuits, CCR locations, PAPI, approach lighting, signs, stop bars and control zones. It must represent the approved system architecture accurately, using distinct status indications.
Each circuit and CCR on the mimic carries its own live status — the operator should never have to guess whether a green dot means "ON and healthy" or just "ON"
CCR Interface, Control & Monitoring
The ALCMS commonly interfaces with Constant Current Regulators. Control and monitoring are different functions — a command may be sent, but the system should also determine whether the CCR actually responded correctly. This distinction is fundamental to ALCMS engineering.
CCR Control
- CCR ON/OFF control
- Intensity step selection
- Local/remote status
A CCR may have multiple output intensity steps, e.g. OFF → Step 1 → Step 2 → Step 3 → Step 4 → Step 5. The actual number and meaning of steps depend on the applicable system design — ALCMS should never assume every airport uses identical intensity configurations.
CCR Monitoring
- Running status & fault status
- Output status & current information
- Alarm status
- Local/remote & communication status
Sending a command is not the same as confirming it was carried out — ALCMS should close the loop, not just fire and forget
How ALCMS Controls Airport Lights: Remote Control, Radio Control & Maintenance
The main ways airport lighting is commanded and looked after, and where ALCMS fits into each.
How Does ALCMS Control Airport Lights?
The operator selects a lighting circuit and the required intensity at the HMI. The control logic validates the command, the communication network carries it to the PLC or RTU and on to the CCR, and the CCR sets the circuit to the selected step. Feedback then returns from the field equipment, and the HMI confirms the status. A command sent is not the same as a command confirmed, so the status must be checked against the field condition.
Airport Lighting Remote Control
Airport lighting remote control means operating the lighting from the control room or tower through ALCMS instead of at the CCR or a local panel. Equipment must be in REMOTE mode for this to work. If it is in LOCAL mode, the central system may not be able to control it, and the HMI should show that mode clearly.
Radio Control Airport Lighting & Airport Lighting Radio Control
Radio control of airport lighting, often called pilot-controlled lighting, lets a pilot switch the aerodrome lighting on or change its intensity by keying the aircraft radio on a designated frequency. A radio receiver at the aerodrome passes the request to the lighting control system, which then operates the selected circuits. It is used mainly where there is no continuously staffed tower. The frequency, activation sequence and intensity response are set by the aerodrome and published in its aeronautical information, so confirm them for the aerodrome concerned.
How Are Airport Lighting Systems Maintained?
ALCMS supports maintenance with fault history, equipment status, event history, alarm trends and circuit identification. It supports field inspection and testing and does not replace them. See AGL testing & inspection for the field side and the troubleshooting atlas for fault finding.
Lighting Circuit Control Across the AGL System
ALCMS organizes lighting circuits according to operational requirements. The control structure should correspond to the approved lighting design and airport operational requirements.
Runway Lighting
Edge, centreline, threshold, end and touchdown zone lighting, plus related approach lighting. The system should clearly identify the selected runway and associated circuits.
Taxiway Lighting
Edge and centreline lights, stop bars, runway guard lights, lead-on and lead-off lighting — often grouped by operational zone to reduce operator workload.
Approach Lighting
ON/OFF and intensity control, circuit monitoring, fault indication and sequencing interfaces where applicable, matched to the approved configuration.
PAPI
ON/OFF, intensity, status, fault and local/remote monitoring. ALCMS control does not prove correct PAPI optical alignment — that must be verified separately.
Illuminated Signs
Power, circuit, status, fault and availability. A sign being electrically energized does not automatically confirm compliant photometric performance.
Stop Bars & Guard Lights
ON/OFF status, intensity, interlocking, route-related control and fault indication — carefully coordinated with the airport's operational and safety systems.
Control Logic, Interlocking & Control Modes
Control logic defines how commands are processed and how the system behaves under normal, abnormal and emergency conditions.
Interlocking
Prevents unsafe or incorrect command combinations — conflicting lighting states, unauthorized control, stop bar coordination and maintenance restrictions, based on the approved operational philosophy.
Local vs Remote
Equipment may run in LOCAL or REMOTE mode. If equipment is in local mode, the central system may not be able to control it — this status must be clearly visible to the operator.
Manual vs Automatic
Manual control lets the operator directly select the required condition; automatic control generates commands from predefined logic or integrated systems and must be carefully engineered.
Individual Control, Group Control & Airport Operations
Individual & Group Control
Individual circuit control lets operators or maintenance personnel isolate specific circuits (runway edge, taxiway, PAPI, approach, sign) — useful for troubleshooting. Group control lets related circuits, e.g. a "Runway 09 Lighting Group," be commanded together, reducing operator workload while keeping a structured control philosophy.
ALCMS, ATC & A-SMGCS
ALCMS is closely connected with airport operations and, at many airports, with ATC. Advanced airports may integrate lighting control with broader surface movement systems (taxi routing, stop bars, ground movement) — while ALCMS remains clearly separated into defined control responsibilities. The operator needs operationally meaningful information: which runway is available, what's active, what intensity is selected, and whether anything is faulty.
Status, Fault, Alarm & Event Monitoring
Monitoring is one of the most valuable ALCMS functions — the goal is to reduce the time between failure occurrence and engineering response.
Status Monitoring
ON, OFF, Fault, Alarm, Local, Remote, Communication failure, Equipment unavailable — accurate, unambiguous and time-referenced where appropriate.
Fault Monitoring
CCR failure/alarm, circuit fault, equipment or communication failure, control failure, power supply or monitoring failure.
Alarm Management
Clear priority, equipment identification, time stamp, description, acknowledgement, restoration status and event history — poor management leads to alarm overload and delayed response.
Event Logging
Commands, lighting changes, fault/alarm occurrence, acknowledgement, recovery, communication failure and system restart — valuable for troubleshooting and records.
Historical Data
Lets engineers identify recurring problems, e.g. "CCR 04 → repeated alarm → same circuit → recurring fault" — supporting preventive maintenance and reliability improvement.
Series Circuit Faults
Open circuits, earth faults, cable insulation degradation, connector problems, transformer or fixture failures — not every field fault is uniquely identified by ALCMS; some require field testing.
Communication, Network, Cybersecurity & Power
Communication Architecture
Fibre optic networks, Ethernet, serial links, industrial networks, remote I/O, PLC and RTU communication — selected for reliability, performance and maintainability.
PLC / RTU Architecture
HMI → Server → PLC/RTU → Communication Network → CCR / Field Equipment. Consider I/O capacity, redundancy, communication reliability, diagnostics, expansion capability and maintenance access.
Cybersecurity
User authentication, access control, network segmentation, controlled remote access, software management, backup, logging and configuration protection — following the airport's approved IT/OT security framework.
Network Engineering
Topology, fibre routing, redundancy, switches, communication paths, segmentation and fault detection. Communication failure should never be confused with field lighting failure.
Power Supply & UPS
UPS, redundant supplies, emergency and backup power for critical equipment. Loss of ALCMS power should be clearly distinguished from loss of field lighting power.
Redundancy
Servers, network paths, power supplies, communication links, controllers and storage — the required level defined by project and airport operational requirements.
ALCMS Engineering Workflow
A practical engineering workflow carries the system from requirement definition through to ongoing maintenance and improvement.
FAT, SAT & Control Loop Verification
ALCMS testing proceeds progressively: Installation Inspection → Power-Up → I/O Test → Communication Test → Control Test → Monitoring Test → Alarm Test → Interlock Test → Functional Test → Integrated System Test. Commissioning should not be considered complete simply because the HMI is operational — the complete control loop must be verified.
Factory Acceptance Testing (FAT)
- Hardware & software verification
- HMI verification
- I/O simulation
- Control logic & alarm testing
- Communication & interlock testing
- Event logging verification
Site Acceptance Testing (SAT)
- Field communication testing
- CCR & lighting circuit control testing
- Monitoring & alarm verification
- Local/remote & interlock testing
- Network & operational scenario testing
Monitoring should also be verified end-to-end: Field Condition → Monitoring Device → Communication → ALCMS → Alarm/Status → Operator. Fault simulation during commissioning confirms the correct alarm is generated.
Common ALCMS Faults — Click to Investigate
A troubleshooting hierarchy prevents engineers from immediately replacing field equipment when the actual problem may lie in the control or communication system: Operator Interface → Control Logic → Communication → Field Controller → CCR → Series Circuit → Field Equipment.
Command does not operate
First Investigation
- Control logic fault
- Communication failure
- Check command & communication status
CCR does not respond
First Investigation
- Equipment in local mode
- CCR fault
- Check CCR mode & alarm status
Wrong status displayed
First Investigation
- Feedback problem
- I/O problem
- Compare HMI status with field equipment
Communication lost
First Investigation
- Network failure
- Fibre or switch failure
- Check the network path
Lighting ON but status OFF
First Investigation
- Feedback failure
- Verify actual field condition
Status ON but light OFF
First Investigation
- Field lighting fault
- Perform field electrical/visual testing
Local/remote conflict
First Investigation
- Equipment in local mode
- Verify control mode
Incorrect intensity
First Investigation
- CCR/control configuration
- Verify command, CCR output & field response
ALCMS, Electrical & Photometric Verification
"HMI shows CCR ON" does not automatically prove "CCR output is correct," and it does not prove "field lights are producing the required photometric output."
ALCMS Status ≠ Electrical Verification ≠ Photometric Verification
These are related but different levels of verification. If photometry shows insufficient intensity, engineers should not automatically assume the fixture is defective — investigate the ALCMS command, CCR output, circuit current, transformer, connector, fixture, optical condition and alignment.
ALCMS vs AGL Control Panel
Control Panel = equipment / local interface. ALCMS = centralized control + monitoring + visualization + event management. The two systems work together.
ALCMS vs CCR
A CCR controls the electrical current supplied to the series circuit. ALCMS controls and monitors the CCR and associated lighting system from the operational interface: ALCMS commands → CCR controls current → Series circuit distributes energy → Isolation transformers interface fixtures → Fixtures produce light.
ALCMS vs Photometry
ALCMS = Control & Monitoring. Photometry = Optical Measurement & Verification. Both are required for a complete understanding of AGL performance.
ALCMS & Maintenance
ALCMS supports maintenance with fault history, equipment status, event history, alarm trends and circuit identification — but it should support field inspection and testing, not replace it.
Airport Lighting Control and Monitoring System: Working Principle & Types
Airport Lighting Control And Monitoring System
An airport lighting control and monitoring system lets operators switch airfield lighting circuits, set intensity and see the status and faults of lights and regulators from one place. In AGL it is usually called ALCMS.
ALCMS Working Principle
ALCMS working principle: operator commands from the HMI go to a server and then to PLCs or remote terminal units at the substations, which switch the CCRs. Status, current and alarm signals travel back the same way for display and logging.
Airfield Lighting Control System Working Principle
The airfield lighting control system working principle is command out, status back. Control signals select circuits and brightness steps at the CCRs, and feedback contacts or readings confirm that the lights actually responded.
ALCMS Types
ALCMS types range from simple relay-based control panels to PLC-based and fully networked systems, centralised or distributed, with or without monitoring, and with local or tower control. The right type depends on runway category and airport size.
Airfield Lighting Control System Types
Airfield lighting control system types include hard-wired panel control, PLC or RTU-based control, and networked computer systems with graphical displays. Larger aerodromes with low-visibility operations normally use the networked type with monitoring.
ALCMS Functions
ALCMS functions are circuit switching, intensity selection, control logic and interlocks, status and fault monitoring, alarm handling, event logging and, in some systems, automatic lighting scenes and reporting.
Airfield Lighting Control System Functions
Airfield lighting control system functions are to give controllers fast, safe control of the lights and to give maintenance staff reliable status, so faults are found and reported before they affect operations.
ALCMS Components
ALCMS components are the servers and operator workstations, HMI software, PLCs or RTUs, field network and fibre or copper links, CCR interface units, power supplies and the alarm and logging system.
Airfield Lighting Control System Components
Airfield lighting control system components include the control panel or workstation, the controller, communication links, interface to the CCR, feedback signals and the supporting power supply, usually with an uninterruptible supply for the control equipment.
Control Panel, Control Room, Tower Interface & Remote Monitoring
Airfield Lighting Control Panel
An airfield lighting control panel gives local or tower control through switches, buttons or a touchscreen with a mimic of the circuits. It is often kept as a manual back-up to the computer system.
Airfield Lighting Control Room
The airfield lighting control room, or the tower cab, holds the operator workstations and displays. Layout should allow clear viewing of circuit status and alarms and quick access to back-up control.
AGL Control Tower Interface
The AGL control tower interface is the display and control point used by air traffic controllers to select lighting circuits and intensity. It must be simple, clearly labelled and show confirmed status rather than only commands.
Airfield Lighting Remote Monitoring
Airfield lighting remote monitoring lets maintenance staff view circuit current, alarms and equipment status away from the substation, over a secured network. Remote access should be limited and protected, see the cybersecurity section.
Airfield Lighting Monitoring System
An airfield lighting monitoring system tracks regulator current and voltage, circuit status, insulation condition where measured, and lamp or light failures where supported, so serviceability limits can be checked.
Airport Lighting Circuit Status Monitoring
Airport lighting circuit status monitoring shows whether each circuit is on, at which step, and within current limits. It is how operators confirm that a command reached the CCR and the lights responded.
AGL SCADA System
An AGL SCADA system is a supervisory control and data acquisition platform used for ALCMS, collecting data from PLCs and RTUs, presenting it on the HMI and logging events for later analysis.
Switching, Intensity Control, PLC, Software & Protocols
Airfield Lighting Switching System
An airfield lighting switching system turns circuits on and off and moves them between brightness steps, through CCR control contacts or digital commands, with interlocks to prevent unsafe combinations.
AGL Switching Sequence
An AGL switching sequence defines the order in which circuits are turned on or changed, for example for a runway configuration or low-visibility procedure, so that the correct lights are lit together.
Airfield Lighting Intensity Control
Airfield lighting intensity control sets the CCR brightness step for each circuit, manually or by pre-set scenes, and is matched to visibility and daylight. The controller should see the confirmed step.
Airfield Lighting PLC Control
Airfield lighting PLC control uses programmable logic controllers to run interlocks, sequences and CCR commands, and to read back status. Logic should be documented and tested, with safe default states on failure.
Airfield Lighting Communication Protocol
An airfield lighting communication protocol carries commands and status between controllers, CCRs and servers. Common industrial protocols such as Modbus or OPC are used, depending on the vendor; confirm what each CCR supports.
Airport Lighting Software
Airport lighting software covers the HMI, mimic displays, alarm and event logging, reports and configuration tools of the ALCMS. Version control, access levels and backups are part of keeping it dependable.
AGL Lighting Design Software
AGL lighting design software is used to lay out lights, circuits, cables and loads before construction, and to produce drawings and schedules. It is separate from the ALCMS runtime software but should feed its circuit data.
AGL Control System Integration
AGL control system integration connects the ALCMS with CCRs, power systems, the tower, other airport systems such as surface movement guidance and weather data, using agreed interfaces that are tested end to end.
ALCMS Requirements, Specification, Design & Selection
ALCMS Requirements
ALCMS requirements come from the runway category, the operational procedures and the applicable standards, covering control speed, monitoring detail, redundancy, back-up control and documentation.
Airfield Lighting Control System Requirements
Airfield lighting control system requirements should state the circuits to control, the monitoring needed, response times, back-up operation, power supply and cybersecurity, based on the operational and regulatory needs of the aerodrome.
Airfield Lighting Control System Specification
An airfield lighting control system specification sets hardware, software, interfaces, performance, testing and documentation. For FAA-based projects it commonly refers to AC 150/5345-56, the L-890 ALCMS specification.
Airfield Lighting Control System Design
Airfield lighting control system design decides the architecture, redundancy, circuit grouping, interlocks, network and power supply, and documents them in drawings, I/O lists and a control philosophy.
ALCMS Selection Guide
ALCMS selection guide: compare architecture, redundancy, supported CCRs and protocols, standards compliance, cybersecurity, local support and lifecycle cost, then check that it fits the airport's size and procedures.
Airfield Lighting Control System Selection Guide
Airfield lighting control system selection guide: choose between panel, PLC and networked types by runway category, number of circuits, expansion plans and maintenance capability, and ask for proof of compliance and references.
ALCMS Technical Guide
ALCMS technical guide: use this page with the vendor manuals, control philosophy, I/O list and network drawings, which together define how the installed system should behave.
Airfield Lighting Control System Technical Guide
Airfield lighting control system technical guide: read it alongside the project drawings, vendor manuals and the airport's operating procedures to confirm design, installation and test details.
Airfield Lighting Control System Standards
Airfield lighting control system standards include ICAO Annex 14 and Aerodrome Design Manual Part 5, FAA AC 150/5340-30 and AC 150/5345-56, and national requirements. See the standards section below.
ALCMS Installation, Testing, Commissioning & Maintenance
ALCMS Installation
ALCMS installation covers mounting cabinets and workstations, laying network and control cables, terminating I/O, earthing and surge protection, and labelling, all following the approved drawings.
Airfield Lighting Control System Installation
Airfield lighting control system installation needs careful cable segregation between control and power circuits, correct earthing, protected communication links and clear labelling to ease later fault finding.
ALCMS Testing Procedure
ALCMS testing procedure runs from factory acceptance through site acceptance, including I/O checks, control loop verification, alarm simulation, communication failure and back-up control tests, with results recorded. See the FAT and SAT section.
Airfield Lighting Control System Testing Procedure
Airfield lighting control system testing procedure checks each command and each status signal end to end, from the HMI to the CCR and back, then tests failure modes and tower hand-over before sign-off.
Airfield Lighting Control System Commissioning
Airfield lighting control system commissioning confirms the installed system matches the design, with every circuit and step verified, alarms proven, documentation handed over and operators trained.
Airfield Lighting Control System Maintenance
Airfield lighting control system maintenance includes checking power supplies and back-up batteries, communication links, software backups and alarm tests, and keeping spares for critical controllers.
ALCMS maintenance
ALCMS maintenance keeps the control and monitoring system reliable. It covers checks of servers, workstations, HMI screens, network and communications links, PLC and field interfaces, alarm and status signals, backups, and software and firmware records. Fault records and test results should be logged so recurring problems can be seen. Intervals and tasks come from the manufacturer and your maintenance plan.
ALCMS Preventive Maintenance
ALCMS preventive maintenance is a scheduled routine of backups, patching under change control, hardware checks, UPS and battery checks and periodic function tests, which reduces unplanned control outages.
Airfield Lighting Control System Preventive Maintenance
Airfield lighting control system preventive maintenance follows a set schedule for inspection, cleaning, testing of control and alarm functions, and replacement of ageing parts, with each task recorded.
Airfield Lighting Control System Troubleshooting
Airfield lighting control system troubleshooting starts by deciding whether the fault is in control, communication or the lighting circuit itself. Check HMI alarms, controller and link status, then the CCR interface and field wiring.
ALCMS Design & Testing Checklist
Before approving an ALCMS design — or signing off testing — verify the system systematically across four areas. Tick items off as you review a project; this resets on reload.
Architecture & Philosophy
HMI, Alarm & Communication
Power & Security
Testing & Documentation
Control & Monitoring Matrix
A useful project document is an ALCMS control and monitoring matrix, always following the approved project architecture.
| Equipment | Control | Status | Fault | Alarm | Intensity | Local/Remote |
|---|---|---|---|---|---|---|
| CCR | Yes | Yes | Yes | Yes | Yes | Yes |
| Runway Circuit | As designed | Yes | As designed | Yes | As designed | As designed |
| Taxiway Circuit | As designed | Yes | As designed | Yes | As designed | As designed |
| PAPI | As designed | Yes | As designed | Yes | As designed | As designed |
| Sign | As designed | Yes | As designed | Yes | As designed | As designed |
| Stop Bar | As designed | Yes | As designed | Yes | As designed | As designed |
Common ALCMS Engineering Mistakes
Treating ALCMS as only an ON/OFF system
Ignores its role in monitoring, alarming and verification.
Ignoring feedback verification
A command sent is not the same as a command confirmed.
Not testing communication failure
The system must be proven under failure, not just normal operation.
Not testing local/remote operation
Mode conflicts should be verified, not assumed correct.
Using unclear alarm descriptions
Ambiguous alarms slow operator response when it matters most.
Not maintaining accurate I/O documentation
Undocumented I/O makes troubleshooting and expansion far harder.
Assuming HMI status equals field condition
Status is a report, not proof — it must be verified in the field.
Not testing interlocks
Untested interlocks can fail exactly when they're needed most.
Ignoring historical alarm analysis
Recurring alarms often point to an underlying system problem.
Failing to maintain software & configuration backups
Leaves the system exposed to prolonged outages after failure.
ALCMS Standards & References
ALCMS engineering should be based on the latest applicable requirements. Exact control functions, monitoring requirements, communication architecture and acceptance criteria should always be taken from the current applicable project and regulatory requirements.
The ALCMS Engineering Principle
An ALCMS is not simply a system that turns airport lights ON and OFF. It is the operational control and monitoring layer that connects airport personnel with the actual AGL system. A command must be transmitted. A response must occur. The response must be monitored. The field condition must be verified. And the event should be traceable.
Provide the required command
Observe equipment & system status
Confirm the action occurred
Act on abnormal conditions
Maintain operational history
Quick Knowledge Check
Q1. What does "CCR commanded ON" from the ALCMS actually confirm on its own?
Q2. If equipment is in LOCAL mode, what should the ALCMS operator expect?
Q3. Photometry shows insufficient runway light intensity even though the ALCMS shows the correct intensity step commanded. What is the correct engineering response?
Explore More AGL Engineering
AGL Design & Electrical Engineering
Understand how ALCMS fits into the overall AGL design.
Open AGL Design & Electrical Engineering →Constant Current Regulators
Understand the equipment that ALCMS controls and monitors.
Explore CCR Engineering →AGL Photometry
Verify the actual optical output of the lighting system.
Open AGL Photometry →AGL Installation & Commissioning
Follow the complete installation and commissioning process.
Open Installation & Commissioning →Runway & Taxiway Lighting
See the field systems that ALCMS controls and monitors day to day.
Open Runway Lighting Systems →All About AGL
Build your understanding of the complete Airfield Ground Lighting system.
Open All About AGL →Surge Protection & Lightning Mitigation
Protect the CCR and control circuits ALCMS monitors from transient damage.
Open Surge Protection →Emergency & Backup Power
Understand the standby power arrangements that keep ALCMS-controlled circuits live.
Open Emergency & Backup Power →Obstruction Lighting & Marking
See how obstruction lights are wired into the same monitored control system.
Open Obstruction Lighting →AGL Cables & Connector Engineering
The field wiring ALCMS monitors for continuity and load.
Open Cables & Connectors →AGL Isolating Transformers
The fixture interface ALCMS indirectly supervises via the series circuit.
Open Isolating Transformers →AGL Testing & Inspection
How ALCMS data feeds ongoing testing and inspection.
Open Testing & Inspection →Runway Incursion Prevention & SMGCS
Selective switching and SMGCS logic layered over ALCMS.
Open SMGCS →Control It. Monitor It. Verify It.
From HMI design to CCR interfacing, from alarm philosophy to commissioning verification — explore the complete ALCMS engineering knowledge base.
Explore the AGL Engineering Knowledge Hub
Fundamentals
Standards & Compliance
Runway, Taxiway & Approach Lighting
Surface Movement & Safety
PAPI
Electrical Engineering & Power
Photometry & Testing
Maintenance, Inspection & Safety
Resources, Documentation & Careers
Frequently Asked Questions
Q1What is ALCMS?
ALCMS stands for Airfield Lighting Control and Monitoring System. It is a centralized system used to control, supervise and monitor airport lighting equipment and circuits, giving operators the interface to control lighting, monitor equipment status, receive fault information, observe alarms and keep an operational record.
Q2Does ALCMS replace the field lighting system?
No. ALCMS connects the operational control environment with field equipment such as Constant Current Regulators, lighting circuits, runway lights, taxiway lights, approach lighting, PAPI, illuminated signs and other visual aids. The exact architecture depends on airport requirements, design, control philosophy, manufacturers and project specifications.
Q3Why is ALCMS important?
Modern airports have many lighting circuits and visual aids, and controlling each from individual equipment locations would be inefficient. ALCMS lets operators select systems, adjust intensity, observe status, identify faults, respond to alarms, verify commands and record events. The objective is controlled, visible and traceable management, not simply turning lights on.
Q4What are the five layers of an ALCMS?
A typical ALCMS has an operator layer (workstation, HMI, display, alarm interface), a control layer (PLC, RTU, control processors, I/O modules), a communication layer (Ethernet, fibre optic, serial and industrial protocols), an equipment layer (CCRs, CCR monitors, control panels, field controllers) and a field layer (series circuits, isolation transformers, fixtures, PAPI, signs, stop bars and runway guard lights).
Q5What is the difference between control and monitoring in ALCMS?
They are two distinct, complementary chains. Control runs from the operator through ALCMS, control logic and communication to the CCR and series circuit. Monitoring runs from the fixture, circuit or CCR back through field monitoring and communication to ALCMS and the operator. Sending a command is not the same as confirming it was carried out, so ALCMS should close the loop.
Q6What is an ALCMS mimic diagram?
The mimic diagram is a graphical representation of the airfield lighting system showing runways, taxiways, lighting circuits, CCR locations, PAPI, approach lighting, signs, stop bars and control zones. It must represent the approved system architecture accurately, with distinct indications for ON, OFF, fault, alarm, communication failure, local control and remote control.
Q7What should an ALCMS HMI let the operator determine?
The operator should always be able to tell what is on, what is off, what is commanded, what has failed and where the problem is. A good HMI provides clear equipment identification, circuit and intensity status, alarm and communication status, fault information, control confirmation, and time and event information.
Q8How does ALCMS control CCRs and intensity steps?
ALCMS commonly interfaces with CCRs for on and off control, intensity step selection and local or remote status. A CCR may have several output steps, for example OFF then Step 1 to Step 5, but the actual number and meaning of steps depend on the system design, so ALCMS should never assume every airport uses identical intensity configurations.
Q9What does the central control system of an ALCMS include?
It is the main interface between airport operations and the lighting system, including the main server, operator workstation, HMI, control software, database, communication interface, alarm system, event logging system and network equipment. It should give clear information about the current state of the lighting system.
Q10What can an ALCMS operator do?
Operators can select lighting circuits, change intensity, view system status, acknowledge alarms, view equipment faults, review events, access system diagrams and monitor communication status.
Q11How to test an ALCMS?
Test an ALCMS in stages: factory acceptance, then site acceptance with a point-to-point I/O check, control loop verification of every circuit and intensity step, alarm simulation, communication failure and back-up control tests, and a final tower hand-over. Record every result.
Q12How to troubleshoot airport lighting control?
First decide whether the fault is in control, communication or the lighting circuit. Check the HMI alarms and link status, then the PLC or RTU, the CCR local/remote setting and interface, and field wiring and power. Measure CCR output current to confirm what the circuit is actually doing.
Q13What is an ALCMS specification?
An ALCMS specification is the technical document that defines what the control and monitoring system must do: functions, architecture, interfaces to CCRs and field equipment, alarms, redundancy, performance, testing and documentation. It is written for the project and forms the basis for procurement and acceptance testing.
Engineering & Expert Notes
Design the Operator Screens for Stress, Not Just Normal Days
HMIClear status, sensible alarm priorities and a simple layout matter most when something goes wrong.
Tune Alarms to Reduce Noise
AlarmsToo many low-value alarms hide the important ones. Review alarm lists and priorities after commissioning.
Treat Cybersecurity as Part of the Design
SecuritySegment networks, control access and manage updates. Plan how the system is maintained securely.
Understand the Local Fallback
FallbackKnow how lights are controlled if the central system or network is unavailable, and test it.
Check Interlocks and Logic After Any Change
LogicControl logic changes can have unexpected side effects. Retest affected functions.
Back Up Configuration and Test Restoration
BackupA backup that has not been restored in a test is only a hope. Verify the process works.
Understand AGL. Build Your Engineering Skills.
You now understand how ALCMS controls and monitors the complete airfield lighting system — from CCR status and alarms to control room operation and system redundancy.
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Move from understanding how AGL works to developing the practical knowledge needed to analyse, operate and maintain complete AGL systems.
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Please read before relying on any content on this page or on any record downloaded from it.
- Purpose and intended users. This page is an independent educational and informational reference for competent, suitably trained and authorised airfield ground lighting (AGL) and aerodrome personnel. It is not professional engineering, legal or regulatory advice, and using it creates no professional or client relationship. Learning-path and Academy references describe stages of learning only and are not a certification, accreditation or authorisation.
- Safety. Work on series circuits, constant current regulators (CCRs), isolating transformers, cables, connectors and lighting fixtures can be fatal. Always apply the aerodrome’s permit-to-work and isolation/LOTO procedures, prove dead, use correctly rated instruments and PPE, and follow the manufacturer’s instructions. Nothing here authorises work on live equipment or the bypassing of any safety device or interlock.
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