Field-ready, tickable checklists for the most common AGL maintenance and fault-response scenarios — from routine daily/weekly/monthly CCR checks, through fixture, cable, connector, and transformer fault response, to PAPI/approach/stop bar checks, earth and insulation fault response, CAT II/III serviceability verification, and time-critical emergency response. Each checklist states its trigger, duration, and personnel requirement up front, groups its steps into logical phases with checkable items, and closes with pass criteria and an escalation path into the relevant fault-isolation division.
Purpose — A quick, daily first-shift verification of CCR health and output status across all series circuits, intended to catch developing faults before they escalate to an operational outage.
All active circuits show current within tolerance for their commanded step, no unacknowledged alarms remain in the log, and no visual abnormality is found on any CCR cabinet.
For an out-of-tolerance current reading, proceed to Division 26 — Fault Isolation Using Circuit Current (ADT-601) and Division 01 — CCR Troubleshooting. For a persistent or repeat alarm, proceed to Division 26 — Fault Isolation Using CCR Alarms (ADT-611). Escalate any cabinet overheating or physical damage immediately per SOP-CCR-04.
SOP: SOP-CCR-01 (Daily CCR Inspection Procedure), SOP-CCR-04 (CCR LOTO Procedure)
Standards: ICAO Annex 14 Vol I, FAA AC 150/5345-10
Cross-reference: Division 01 — CCR Troubleshooting; Division 26 — ADT-601, ADT-611
Purpose — A more thorough weekly review of CCR performance trends, insulation condition indicators, and secondary circuit health beyond the daily quick check.
No circuit shows a worsening trend beyond the defined threshold, cooling/thermal checks show normal operation, and the spot insulation check meets the minimum acceptable value.
For a worsening current trend, proceed to Division 26 — Fault Isolation Using Failure Pattern Analysis (ADT-614). For a low insulation resistance reading, proceed to Fault Isolation Using Insulation Resistance (ADT-603). For a thermal anomaly, proceed to Fault Isolation Using Thermal Inspection (ADT-607).
SOP: SOP-CCR-02 (Weekly CCR Maintenance Procedure), SOP-ADT-03
Standards: ICAO Annex 14 Vol I, FAA AC 150/5345-10
Cross-reference: Division 01 — CCR Troubleshooting; Division 26 — ADT-603, ADT-607, ADT-614
Purpose — A comprehensive monthly deep-inspection of the CCR covering full-loop insulation testing, calibration verification, and control/interlock system checks, aligned with the periodic PM programme.
All loop insulation resistance readings meet or exceed the minimum standard, calibration is within tolerance at every step, all alarm functions trip correctly, and no component shows wear beyond acceptable limits.
For failed insulation resistance, proceed to Division 26 — Fault Isolation Using Insulation Resistance (ADT-603) and the relevant circuit-specific division. For calibration drift, schedule CCR regulator service per manufacturer procedure. For a non-tripping alarm function, escalate for CCR internal service before returning the circuit to unsupervised service.
SOP: SOP-CCR-03 (Monthly CCR Deep Inspection Procedure), SOP-ADT-03, SOP-CCR-04
Standards: ICAO Annex 14 Vol I, FAA AC 150/5345-10, IEC 60364
Cross-reference: Division 01 — CCR Troubleshooting; Division 26 — Advanced Diagnostic Topics
Purpose — A structured field checklist for diagnosing a reported runway edge, centreline, threshold, or touchdown zone light fault, from initial report through to confirmed resolution.
The fixture operates correctly at all commanded intensity steps, current/voltage readings are within tolerance, and no residual alarm remains for the fixture or circuit.
Route to the specific division covering the confirmed fault type — Division 05 (Runway Centreline), Division 06 (Touchdown Zone), the relevant fixture/cable/connector/transformer checklist, or Division 26 for general fault-isolation method selection.
SOP: SOP-RCL-01 (Runway Light Fault Response Procedure)
Standards: ICAO Annex 14 Vol I, FAA AC 150/5340-30
Cross-reference: Division 05, Division 06, Division 26
Purpose — A structured field checklist for diagnosing a reported taxiway edge, centreline, or guidance light fault.
The fixture operates correctly, shows the correct design colour, and current/voltage readings are within tolerance with no residual alarm.
Route to Division 07 (Taxiway Light), Division 08 (Taxiway Centreline Guidance Light), or Division 26 for method selection. A colour discrepancy routes to Division 18 — PHM-458 (Wrong Light Colour).
SOP: SOP-TWY-01 (Taxiway Light Fault Response Procedure)
Standards: ICAO Annex 14 Vol I, FAA AC 150/5340-30
Cross-reference: Division 07, Division 08, Division 18, Division 26
Purpose — A structured checklist for diagnosing a suspected isolation transformer fault, whether identified from a circuit-level current anomaly or a direct field report.
Winding resistance and insulation resistance both meet specification, no physical damage is present, and the associated fixture operates normally after restoration.
Proceed to Division 26 — Fault Isolation Using Insulation Resistance (ADT-603) and Fault Isolation Using Resistance Measurement (ADT-604). Replace the transformer per SOP-XFMR-01 if any test fails.
SOP: SOP-XFMR-01 (Isolation Transformer Test and Replacement Procedure)
Standards: IEC 60364, ICAO Annex 14 Vol I
Cross-reference: Division 26 — ADT-603, ADT-604, ADT-615
Purpose — A structured checklist for diagnosing a suspected primary or secondary cable fault, typically triggered by an insulation resistance failure, an open/short circuit indication, or a confirmed water ingress event.
The repaired section and full loop both meet the minimum insulation resistance standard, and circuit current returns to the expected value at the commanded step.
Continue sectional/bisection testing per Division 26 (ADT-616) and segmentation testing (ADT-618) until the fault is fully bracketed. Escalate to engineering review if the cable shows a systemic/batch issue (cross-reference ADT-614).
SOP: SOP-CBL-01 (Cable Fault Location and Repair Procedure)
Standards: IEC 60364, ICAO Annex 14 Vol I
Cross-reference: Division 26 — ADT-603, ADT-616, ADT-618
Purpose — A structured checklist for diagnosing a suspected connector fault at a base can, junction, or fixture pigtail, a common cause of intermittent or fully dark fixtures.
The connector shows continuity, contact resistance comparable to a known-good unit, and the associated fixture operates normally after restoration.
Proceed to Division 26 — Fault Isolation Using Continuity Testing (ADT-605) and Fault Isolation Using Resistance Measurement (ADT-604). Replace the connector per SOP-CON-01.
SOP: SOP-CON-01 (Connector Inspection and Replacement Procedure)
Standards: ICAO Annex 14 Vol I, IEC 60364
Cross-reference: Division 26 — ADT-604, ADT-605
Purpose — A structured checklist for diagnosing a fault on an illuminated airfield sign (mandatory instruction, information, or directional sign), covering both the internal lighting/photometric system and the sign panel itself.
The sign is fully and evenly illuminated, the legend is correct and legible, and supply voltage/current is within specification.
For an electrical fault, proceed to Division 26 — Fault Isolation Using Circuit Voltage (ADT-602). For uneven illumination, cross-reference Division 18 — PHM-453. For panel damage, escalate for sign panel replacement.
SOP: SOP-SIGN-01 (Illuminated Sign Inspection Procedure)
Standards: ICAO Annex 14 Vol I, FAA AC 150/5340-30
Cross-reference: Division 18, Division 26
Purpose — A structured checklist for diagnosing a fault in a Precision Approach Path Indicator (PAPI) unit, covering electrical, aiming, and photometric checks given the safety-critical nature of glide path guidance.
All lamp positions show the correct red/white transition at the design glide path angle, electrical readings are within tolerance, and no residual alarm remains.
For aiming, proceed to Division 18 — PHM-454 (Beam Misalignment). For a lamp-level electrical fault, proceed to Division 26 — Fault Isolation Using Circuit Current/Voltage (ADT-601/602). Treat any PAPI fault as high priority given its role in approach guidance.
SOP: SOP-PAPI-01 (PAPI Inspection and Aiming Procedure)
Standards: ICAO Annex 14 Vol I, FAA AC 150/5340-30
Cross-reference: Division 09, Division 18, Division 26
Purpose — A structured checklist for diagnosing a fault on an approach lighting system fixture (e.g., sequenced flashing light, approach centreline/crossbar light), given the system’s role in low-visibility approach guidance.
The fixture operates correctly at all commanded steps, sequenced flashing (if applicable) shows correct timing, and no residual alarm remains.
Route to Division 09 — Approach Lighting System Troubleshooting or Division 26 for method selection. A flasher/controller timing fault escalates to the sequenced flasher controller maintenance procedure.
SOP: SOP-ALS-01 (Approach Light Fault Response Procedure)
Standards: ICAO Annex 14 Vol I, FAA AC 150/5340-30
Cross-reference: Division 09, Division 26
Purpose — A structured checklist for diagnosing a fault on a runway-holding position stop bar light, given its role as a critical runway incursion prevention control, particularly under CAT II/III low-visibility procedures.
All fixtures in the stop bar show correct red colour, respond correctly to the on/off control command, and current readings are within tolerance with no residual alarm.
Given the safety-critical nature of a stop bar, treat any confirmed fault as high priority. Route to the relevant Division 26 fault-isolation method and, if colour is affected, Division 18 — PHM-458. Do not restore the stop bar to unsupervised CAT II/III service until fully verified.
SOP: SOP-STB-01 (Stop Bar Fault Response Procedure)
Standards: ICAO Annex 14 Vol I, FAA AC 150/5340-30
Cross-reference: Division 18, Division 26, Division 28 — CHK-657/CHK-658
Purpose — A structured checklist for diagnosing a confirmed or suspected earth (ground) fault on an AGL circuit, typically triggered by a CCR ground-fault alarm.
The full loop meets the minimum insulation resistance standard, the ground/earth conductor shows no unexpected current under normal operation, and the CCR ground-fault alarm does not recur.
Continue bracketing per Division 26 — Fault Isolation Using Insulation Resistance (ADT-603), Sectional Testing (ADT-616), and Circuit Segmentation (ADT-618) until the fault is located. Do not restore the circuit to unsupervised service with a confirmed but unresolved ground fault.
SOP: SOP-GND-01 (Earth Fault Location and Repair Procedure)
Standards: IEC 60364, ICAO Annex 14 Vol I
Cross-reference: Division 26 — ADT-603, ADT-606, ADT-616, ADT-618
Purpose — A structured checklist for diagnosing and confirming a suspected insulation failure identified from a low insulation resistance reading during scheduled testing or as part of another fault investigation, distinct from a confirmed ground-fault alarm event.
The affected segment and full loop both meet or exceed the minimum acceptable insulation resistance value on a repeated, confirmed test.
Continue bracketing per Division 26 — Fault Isolation Using Insulation Resistance (ADT-603) and Sectional Testing (ADT-616). If the reading only fails under specific environmental conditions, proceed to Environmental Reproduction (ADT-619).
SOP: SOP-INS-01 (Insulation Failure Investigation Procedure)
Standards: IEC 60364, ICAO Annex 14 Vol I
Cross-reference: Division 26 — ADT-603, ADT-616, ADT-619
Purpose — A structured checklist for conducting and closing out a photometric fault investigation on a fixture flagged by scheduled testing, a field report, or a preceding electrical/visual check, drawing on the full Division 18 topic set.
All tested parameters (intensity, alignment, spread, chromaticity) fall within their specified tolerances on a confirmed, repeated measurement.
Route to the specific Division 18 topic matching the failed parameter (PHM-451 through PHM-458). If the failure appears to be measurement-side rather than fixture-side, route to PHM-459 through PHM-467.
SOP: SOP-PHM-01 (Field Photometric Test Procedure)
Standards: ICAO Annex 14 Vol I Attachment A, FAA AC 150/5340-30
Cross-reference: Division 18 (full topic set); Division 26 — ADT-609
Purpose — A structured checklist for diagnosing a fault in the ALCMS itself (communication loss, incorrect status reporting, control command failure) as distinct from a field circuit or fixture fault that ALCMS happens to be reporting.
ALCMS-reported status matches field-confirmed status for all affected points, and control commands produce the correct field response.
For a confirmed field-level fault reported correctly by ALCMS, route to the relevant fixture/circuit division. For a confirmed ALCMS-side fault, escalate per Division 26 — Fault Isolation Using ALCMS Data (ADT-612) and involve IT/controls support as needed.
SOP: SOP-ALCMS-01 (ALCMS Fault Response Procedure)
Standards: ICAO Annex 14 Vol I
Cross-reference: Division 26 — ADT-610, ADT-612
Purpose — A structured checklist for verifying and, where needed, restoring AGL system compliance for CAT II low-visibility operations, covering the additional fixtures, redundancy, and tolerance requirements specific to CAT II beyond standard AGL service.
All CAT II-critical elements meet their fixture serviceability, redundancy, and photometric requirements, and standby power/control functions verify correctly.
Do not declare or maintain CAT II serviceability with a confirmed deficiency. Issue or maintain the appropriate NOTAM and route the specific fault to its relevant division (Division 05/06/09, CHK-652, or Division 26 for method selection).
SOP: SOP-CAT2-01 (CAT II Serviceability Verification Procedure)
Standards: ICAO Annex 14 Vol I (CAT II/III provisions), FAA AC 150/5340-30
Cross-reference: Division 05, Division 06, Division 09, Division 26
Purpose — A structured checklist for verifying and, where needed, restoring AGL system compliance for CAT III low-visibility operations, covering the more stringent redundancy, tolerance, and fixture serviceability requirements beyond CAT II.
All CAT III-critical elements meet the stricter fixture serviceability, full redundancy, and photometric tolerance requirements, with all standby and monitoring functions verified.
Do not declare or maintain CAT III serviceability with any confirmed deficiency. Downgrade to the appropriate operational category (CAT II or visual) via NOTAM and route the specific fault to its relevant division.
SOP: SOP-CAT3-01 (CAT III Serviceability Verification Procedure)
Standards: ICAO Annex 14 Vol I (CAT II/III provisions), FAA AC 150/5340-30
Cross-reference: Division 05, Division 06, Division 09, Division 26, Division 28 — CHK-657
Purpose — A structured checklist for diagnosing AGL faults reported during or immediately after rain events, targeting the specific fault modes (water ingress, insulation degradation, connector corrosion) most commonly triggered by wet conditions.
No standing water remains in any inspected enclosure, insulation resistance and current readings meet specification on all affected circuits, and no residual ground-fault alarm remains.
Continue insulation resistance and sectional testing per Division 26 (ADT-603, ADT-616). For a confirmed environmentally-triggered but not-yet-reproduced intermittent fault, proceed to Environmental Reproduction (ADT-619). Flag repeat locations for failure pattern analysis (ADT-614).
SOP: SOP-RAIN-01 (Rain-Related Fault Response Procedure)
Standards: IEC 60364, ICAO Annex 14 Vol I
Cross-reference: Division 26 — ADT-603, ADT-610, ADT-614, ADT-616, ADT-619
Purpose — A structured, time-critical checklist for responding to an AGL fault that directly and immediately affects runway/taxiway safety or operational availability (e.g., a fully dark runway section, a failed stop bar, or a CAT II/III-invalidating fault during active low-visibility operations), prioritising rapid safe response over full root-cause diagnosis.
The immediate operational hazard is fully mitigated (either by verified restoration or by an appropriate, communicated restriction), and operations/ATC have received timely, accurate status updates throughout.
If full restoration is not achievable within the immediate response window, maintain the appropriate operational restriction and hand off to the relevant division checklist and Division 26 methods for full diagnosis. Do not lift a safety restriction based on an unverified fix.
SOP: SOP-EMG-01 (Emergency AGL Fault Response Procedure)
Standards: ICAO Annex 14 Vol I
Cross-reference: All relevant division checklists; Division 26 — Advanced Diagnostic Topics
Quick answers about the Troubleshooting Checklist Library in the AGL Troubleshooting Atlas.
Division 28 is the Troubleshooting Checklist Library. It publishes 20 ready-to-use checklists, CHK-641 to CHK-660, for CCRs, lighting circuits, transformers, cables, connectors, signage, PAPI, approach and stop bar lights, earth and insulation faults, photometry, ALCMS, CAT II/III readiness, rain-related faults and emergencies.
The 20 checklists are CHK-641 Daily CCR Troubleshooting Checklist; CHK-642 Weekly CCR Troubleshooting Checklist; CHK-643 Monthly CCR Troubleshooting Checklist; CHK-644 Runway Light Fault Checklist; CHK-645 Taxiway Light Fault Checklist; CHK-646 Transformer Fault Checklist; CHK-647 Cable Fault Checklist; CHK-648 Connector Fault Checklist; CHK-649 Signage Fault Checklist; CHK-650 PAPI Fault Checklist; CHK-651 Approach Light Fault Checklist; CHK-652 Stop Bar Fault Checklist; CHK-653 Earth Fault Checklist; CHK-654 Insulation Failure Checklist; CHK-655 Photometry Fault Checklist; CHK-656 ALCMS Fault Checklist; CHK-657 CAT II Fault Checklist; CHK-658 CAT III Fault Checklist; CHK-659 Rain-Related Fault Checklist; CHK-660 Emergency AGL Fault Checklist.
Every checklist has a purpose statement, frequency and scope (how often, how long and how many technicians), safety precautions, the checklist items grouped by activity, pass/completion criteria, what to do if any item fails, and related references.
The 20 checklists contain 268 checkable items in total. Each checklist shows a running count of checked items, for example 0 / 14 for the Daily CCR Troubleshooting Checklist (CHK-641).
CHK-641 Daily CCR Troubleshooting Checklist, CHK-642 Weekly CCR Troubleshooting Checklist and CHK-643 Monthly CCR Troubleshooting Checklist cover routine CCR verification. The Daily checklist is a first-shift check of CCR health and output status intended to catch developing faults before they cause an outage.
No. Each checklist states its own safety precautions. For example, the Daily CCR Troubleshooting Checklist is a visual/reading-only check for which LOTO is not required, but it says not to open any energised cabinet beyond the viewing window or front panel and to report visible smoke, arcing or unusual odour immediately.
Each checklist has an 'If Any Item Fails' section that says what to do next and points to the relevant Atlas topics. For example, an out-of-tolerance current reading on the Daily CCR Troubleshooting Checklist points to Division 26 (Fault Isolation Using Circuit Current, ADT-601) and Division 01 (CCR Troubleshooting).
Yes. Each checklist has a Word (.doc) download so it can be used or filed outside the website.
A checklist tells you what to check — it doesn't tell you why that check catches the fault it's designed to catch.
Build the technical knowledge to understand the diagnostic logic behind every checklist step, so you can adapt when a fault doesn't fit the standard sequence.
Diagnose systematically. Understand the circuit. Build real AGL expertise.
Please read before relying on any content on this page or on any record downloaded from it.