The dedicated maintenance framework for the Airfield Lighting Control and Monitoring System (ALCMS) and its associated control, monitoring, communication and interface equipment. Division 17 maintains the complete control chain — from the operator's command, through the PLC, interface and CCR, out to the field, and back through feedback, alarm and event recording.
Objective: confirming that the ALCMS screen is operational is not sufficient. The complete chain of command, execution, feedback, alarm and event recording must be verified on every applicable task in this division.
Core rule: a control command is not considered verified until command, equipment response, feedback and event/alarm behaviour have all been confirmed.
Every ALCMS maintenance task — preventive, corrective or functional — is judged against the same end-to-end control chain, not against the HMI screen alone.
Five fundamental functions underpin every verification in this division.
Can the operator issue the required command?
Does the command reach the intended equipment?
Does the ALCMS correctly indicate equipment status?
Does the system identify abnormal conditions?
Does the system correctly record the event and system response?
When an ALCMS command does not produce the expected response, the fault is traced through the same eight-point chain regardless of which topic in this division is being worked.
Is the command being generated?
Is the command leaving the HMI/ALCMS?
Is the PLC receiving/processing the command?
Is the interface transmitting the command?
Is the CCR in remote mode and receiving the command?
Is the AGL equipment responding?
Is the actual condition returning to the ALCMS?
Is the HMI displaying the correct condition?
Before any Division 17 task begins, four requirement groups must be closed out.
Grouped by maintenance category — click any topic to expand its verification activities and acceptance condition.
Check: cleaning does not disturb connections or equipment ventilation.
Check: for unexpected error messages or abnormal system behaviour.
Any discrepancy between command, receipt, and equipment response should be investigated.
Use: an approved test method that does not create an unintended operational condition.
Check: timestamps and event descriptions are meaningful.
Do not modify PLC logic during routine inspection unless specifically authorized.
Note: interface failures can create discrepancies between the ALCMS command and field equipment response.
Where managed: review available diagnostic information.
Investigate: any abnormal power condition — control-system instability may originate from the power supply.
Follow: the UPS manufacturer's maintenance requirements for detailed battery testing.
Note: poor cooling can contribute to premature electronic-component failure.
Where external time source used: verify synchronization status where applicable.
Configuration backups should be controlled and traceable.
Follow: the airport's approved cybersecurity and access-control procedures.
After correction, verify: Display → Status → Command → Feedback.
PLC program/configuration changes should only be performed by authorized personnel under appropriate change control.
Use: approved compatible components only.
After correction: perform controlled alarm verification.
The complete chain should be verified — not just that the ALCMS accepted the command.
Note: the number and definition of intensity steps follows the installed system configuration and applicable operational requirements.
Any mismatch should be treated as a control/monitoring defect.
Control: alarm testing so that it does not compromise live airfield operations.
This is the final gate: the complete control chain must be verified before the system is returned to service.
Every finding in this division is classified against the same five-tier scale, driving the appropriate action.
| Condition | Description | Action |
|---|---|---|
| Good | Fully functional and stable | Routine PM |
| Acceptable | Minor non-critical deterioration | Monitor |
| Deteriorating | Developing hardware/software/communication issue | Planned maintenance |
| Defective | Control/monitoring function compromised | Corrective maintenance |
| Critical | Loss of essential control/monitoring function | Priority/emergency response |
The strongest principle for Division 17 governs every one of its 39 topics, whether preventive, corrective, or functional.
Do not verify only the screen — verify the complete control loop. Operator → HMI → ALCMS → PLC/Control Logic → Interface → CCR → AGL Field System → Feedback → Alarm/Event Log → HMI Status. This makes Division 17 the control, monitoring and information-integrity backbone of the AGL Maintenance Handbook.
Quick answers about alcms & control system maintenance, based on the topics in this division.
It is the dedicated framework for the Airfield Lighting Control and Monitoring System and its associated control, monitoring, communication and interface equipment.
Division 17 (ALCMS & Control System Maintenance) contains 39 topics in three groups: Group A Preventive Maintenance (20 topics), Group B Corrective Maintenance (11 topics) and Group C Functional Maintenance (8 topics).
No. The complete chain of command, execution, feedback, alarm and event recording must be verified. A control command is not considered verified until the command, equipment response, feedback and event or alarm behaviour have all been confirmed.
Control (can the operator issue the command), Execution (does it reach the intended equipment), Feedback (does ALCMS correctly indicate equipment status), Alarm (does the system identify abnormal conditions) and Record (does it correctly record the event and system response).
Operator/HMI, ALCMS, PLC/control logic, interface, CCR, AGL series circuit, field equipment, then feedback returning to ALCMS. Every task is judged against this end-to-end chain, not the HMI screen alone.
When a command does not produce the expected response, trace an eight-point chain: is the command generated at the HMI, leaving the HMI/ALCMS, received and processed by the PLC, transmitted by the interface, received by a CCR in remote mode, and acted on by the field system, and is the actual condition then returned as feedback and shown correctly on the display.
Four requirement groups. Work planning covers identifying the system, reviewing history and alarms, and confirming authorized personnel for any PLC or configuration change. Operational coordination covers work authorization and coordinating with ATC or airport operations before any live command test. Safety and access covers isolation or LOTO where required and approved cybersecurity and access-control procedures. Documentation covers the work order, system identification, initial condition and the backup or configuration reference in use.
Good (fully functional and stable, routine PM), Acceptable (minor non-critical deterioration, monitor), Deteriorating (developing hardware, software or communication issue, planned maintenance), Defective (control or monitoring function compromised, corrective maintenance) and Critical (loss of an essential control or monitoring function).
ALCMS maintenance is more than restarting a frozen workstation.
Build the technical knowledge to understand control architecture, command/feedback pathways, database integrity, and how a control-system fault propagates to every circuit it manages.
Maintain the system. Understand the logic. Protect the control chain.
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