WHAT IS AGL COMMISSIONING?
Commissioning proves that an installed AGL system is installed correctly, electrically safe, functionally operational, optically compliant, correctly controlled and properly documented. It is not just switching on the CCR and seeing lamps light. The whole chain is in scope:
plus signs, PAPI, ALCMS, emergency power and the marking interface. Testing measures one parameter (insulation, continuity, CCR current, fixture intensity); commissioning combines the tests with functional operation, integration, control, monitoring, alarms, final settings, documentation and operational acceptance.
Memory
- TEST = CHECK · COMMISSION = PROVE THE SYSTEM
- Objectives: safety, correct installation, electrical and optical performance, control, monitoring, documentation
Main FAA references: AC 150/5340-26C (maintenance, safety, test equipment, series-circuit troubleshooting) and AC 150/5340-30J (design and installation), with separate equipment specifications for CCRs, transformers, connectors, fixtures, PAPI and signs.
TYPES OF TESTING: FAT, SAT, PRE-COMMISSIONING
| Stage | Where / when | Focus |
|---|---|---|
| FAT | Factory, before shipment | Equipment compliance: CCR, transformers, fixtures, signs, PAPI, panels |
| SAT | Site, after installation | Wiring, power, function, control, circuit performance, integration |
| Pre-commissioning | Before energisation | Find mistakes before live operation |
| Commissioning | Whole system | Final proof of performance |
The full sequence is set by the project ITP (Inspection & Test Plan) and method statements: material receiving, FAT, pre-installation, pre-commissioning, SAT, electrical, functional, photometric, control and monitoring, integrated, standby power, final inspection, performance verification and handover.
PREPARATION, DOCUMENTS, EQUIPMENT
Documents needed
Approved drawings and layout, single-line diagrams, cable, circuit, transformer and fixture schedules, sign schedule, PAPI drawings, CCR datasheets, manuals, ITP, method statements, risk assessment, FAT reports, calibration certificates, approved redlines.
Material inspection
Make, model, part number, quantity, rating, certification, condition, accessories. CCR current/class, transformer wattage/current/frequency, connector Type/Class/Style, fixture model.
Traceability
Manufacturer, serial, batch, part number, circuit number, location, test report number, especially for transformers, CCRs, PAPI and signs.
Calibration
Unique instrument ID, valid certificate, calibration and next-due dates, traceability. Do not base acceptance on uncalibrated instruments where calibrated ones are required.
Typical tools: true-RMS multimeter, clamp meter, insulation tester, continuity and voltage testers, AGL circuit tester, cable fault locator, TDR, PAPI aiming tool, level or survey equipment, photometric equipment, torque wrench, thermal camera and service laptop.
CABLE, CONTINUITY AND INSULATION TESTING
Pre-commissioning inspection covers electrical (panels, CCR, terminations, transformers, connectors, earthing), mechanical (fixtures, bases, frangible fittings, sign supports), optical (lens, filters, orientation) and civil (pits, foundations, drainage, cable routes). Before energising, confirm the numbering: CCR circuit = cable circuit = transformer circuit = fixture circuit.
Continuity
Finds open conductors, broken cable, open connectors or transformer windings. Continuity PASS ≠ circuit PASS: poor insulation, moisture or high-resistance joints can still be present.
Insulation resistance
Primary to ground, cable sections, transformers, secondary circuits. AC 150/5340-26C says there is no single ideal value; readings depend on length, age, equipment, installation, weather and moisture, so use consistent conditions.
Trending
Example only: 500 → 220 → 35 MΩ over three years is significant even before a limit is crossed. A trend can beat a single reading.
Acceptance values
AC 150/5340-26C notes that a series circuit below 1 MΩ generally points to rapid failure, but this is not a universal acceptance limit. Use the project specification, manufacturer requirement and standard.
Cable faults: open, short, ground fault, high-resistance joint, intermittent (moisture, temperature, movement). AC 150/5340-26C has procedures for ground faults, open circuits and interconnected series-circuit faults. Interrelated notes: Note 09.
TRANSFORMERS, CONNECTORS AND FIXTURES
| Item | Verify |
|---|---|
| Transformer | Type, wattage, primary and secondary current, frequency, connector configuration, condition; continuity, insulation, current/ratio and dielectric tests where required; record Transformer ID → Circuit ID → Fixture ID (Note 08) |
| L-823 connector | Type, Class, Style, mating half, cable compatibility, pin/socket, housing, sealing, contamination; continuity and insulation per procedure. "It fits" is not acceptance (Note 10) |
| Elevated fixture | Location, height, alignment, stable and frangible mounting, clean lens, cable connection; misalignment changes apparent brightness |
| In-pavement fixture | Elevation to pavement, orientation, bolt torque, lens, base, transformer, connector, drainage, water ingress |
Fixtures: AC 150/5345-46F covers runway, taxiway, heliport and vertiport light fixtures. Also check pits and junction boxes (water, drainage, cable arrangement, covers, sealing), and verify torque where specified for CCR and panel terminals, fixture bolts, grounding and sign connections.
CCR TESTING AND ENERGISATION
Before energising, check input supply, output circuit, current setting, circuit identification, protection, control wiring, monitoring, earthing and interlocks. Then test each step: selected step, measured current, output voltage, load or power, alarm, remote indication. AC 150/5340-26C gives tolerance tables for 3-step and 5-step regulators.
Local and remote
Local OFF/ON and each step; remote ON/OFF, intensity, status, fault, reset. Confirm commands at both control room and CCR.
Monitoring and faults
Use the manufacturer-approved method to simulate faults. Do not create live faults unsafely.
Loading
Check load, current, output voltage and regulation on the installed circuit. Open-secondary transformers can alter inductive load and CCR behaviour; never improvise this on an operational circuit.
Thermal and torque
Thermal imaging finds hot terminals and connector heating (a diagnostic aid, not a substitute for electrical tests).
Do not energise the whole circuit at maximum intensity at once; follow the airport's approved procedure. At each brightness step check light on, colour, apparent intensity, flicker, heating, fault indications and transformer or connector abnormality. See Note 07.
FIELD SYSTEM TESTS
| System | Verify |
|---|---|
| Runway edge | Operation, colour, spacing, location, orientation, brightness, circuit |
| Centerline | Colour coding toward the runway end (white, then alternating red/white, then red), spacing, intensity, circuit, photometry where required |
| Threshold / end | Correct colour from each viewing direction |
| Taxiway | Edge, centerline, stop bars, guard lights: operation, colour, intensity, spacing, circuit, control |
| Stop bar | Red indication, ON/OFF control, brightness, monitoring, interlocking |
| Runway guard lights | Alternating yellow flash function (flash rate and alternation), location, control, monitoring |
| Approach lighting | Locations, sequence, intensity, colour, alignment, structure, control |
PAPI
Commissioning is more than "all 4 boxes ON": supply and transformer/PCU/CCR arrangement, foundation, level, alignment, red/white transition, intensity, beam and aiming. Check each unit against its approved design angle, never a generic angle from another runway; verify horizontal alignment, vertical angle, level, spacing, elevation and tilt protection (Note 11).
Signs
Check legend against the approved sign schedule and signage drawing (taxiway and runway designation, arrow, mandatory instruction, destination, location), brightness, uniform illumination, no dark areas, correct circuit, control and status. One wrong letter is an operational problem even when the sign is electrically perfect (Note 13).
CONTROL, ALCMS, STANDBY POWER AND EARTHING
ALCMS
Communication, device and circuit status, ON/OFF, brightness, alarms, faults, event logging, local/remote status. Test the full command-and-feedback loop: control room → CCR → field lights → status back.
Local vs remote
Priority logic, interlocks, indication, safe recovery. Examples: wrong circuit selection blocked, safety interlock prevents operation, maintenance mode restricts remote command.
Alarms and cause-effect
Match a cause-and-effect matrix: CCR fault, circuit fault, power or communication failure, sign fault, PAPI fault, standby status. Record expected vs actual and PASS/FAIL.
Control networks
Hardwired, fibre, Ethernet, serial or field bus: continuity, insulation, termination, shield bonding, addressing, signal integrity. Fibre: link status, connector cleanliness, optical loss, redundancy. PLC/SCADA: I/O, interlocks, HMI, event log, time sync.
Standby power
Transfer operation, backup availability, CCR restart, lighting continuity, alarm, return to normal. Measure the transfer time against the required switch-over time (ICAO Annex 14 Table 8-1: generally 15 s, or 1 s for key CAT II/III lights; see Note 05). Never interrupt power uncontrolled on an operational runway.
Earthing and lightning
CCR, panel, sign, PAPI and structure bonding, with measured values where required; check surge devices and arresters for burn marks and inspect equipment after lightning.
PHOTOMETRY AND INSPECTIONS
Photometry verifies intensity, colour, beam distribution, alignment and uniformity. Visual inspection says "the light appears to work"; photometry says "measured output meets the requirement". ON ≠ COMPLIANT. Electrical PASS does not automatically mean photometric PASS.
| Photometric level | Scope |
|---|---|
| Fixture | Individual fixtures |
| Circuit | Performance across a circuit |
| Runway survey | Installed system at defined points |
| PAPI | Optical performance and beam geometry |
Before testing: equipment ID, valid calibration, sensor condition, verified distance and geometry. Record date, time, weather, visibility, temperature, setup, brightness step and instrument ID. The measurement grid and acceptance limits come from the standard or project specification.
Night inspection suits actual light operation; FAA guidance expects daily twilight or night patrols for dim, burnt-out or misaligned lights and lens cleanliness. Record each defect by location + fixture ID + circuit ID. Daytime inspection suits physical condition: pits, signs, foundations, pavement interface. Coordinate any operational runway test with operations and ATC; low-visibility configurations, centerline guidance, stop bars, sign operation, PAPI, control logic and emergency arrangements are tested only under the approved safety procedure.
FAULT-FINDING AND FAILURES
| Symptom | Check |
|---|---|
| No lights | Power → control → CCR → primary circuit |
| Many lights off | Control → CCR → primary circuit → primary connectors → transformer section |
| One light off | Fixture → secondary connector → secondary cable → transformer → primary connection |
| Low insulation | Cable → joint → transformer → connector → moisture |
| Low intensity | Current → transformer → connector → fixture → photometry |
| Wrong PAPI indication | Aiming → level → optics → photometry |
| CCR trips on energising | Fault indication, input, protection, primary circuit, ground or short fault, loading, diagnostics |
| CCR fine on low steps, fails high | Circuit load and impedance, CCR capacity, internal fault, inductive effects |
| Sign dark but intact | Power → control → driver → LED → internal wiring |
Use fault simulation only per the ITP: fault → detection → alarm → correct indication → recovery, then verify reset, status recovery, no false alarm and event logging.
PUNCH LIST, NCR AND RETEST
Punch list
Electrical (labels, terminals, insulation, wrong connection), mechanical (alignment, sign damage, foundations), optical (low intensity, colour, PAPI aim), documentation (missing certificates, expired calibration, drawings).
Categories
A: safety or operationally critical. B: important technical defect. C: minor, documentation or cosmetic. Follow the contract quality procedure.
NCR
Raise when an installed or tested item misses the approved requirement. Never alter a record to make it pass.
Retest
Repair → retest → record → close NCR. A replaced component is not a closed failure until retested.
Accept on the approved requirement, not "it looks okay": drawing, project specification, ITP, manufacturer manual, FAA specification, ICAO or national requirement. Practical hierarchy: law or regulator → airport requirement → project specification → drawing/ITP → manufacturer requirement → test procedure → measured result. Resolve conflicts formally.
TEST RECORDS AND ITP
| Record | Key fields |
|---|---|
| Test sheet | Item, requirement, measured value, instrument, result, remarks |
| Cable insulation | Airport, circuit, CCR, cable, date, weather, test voltage, duration, measured IR, instrument ID, calibration due, technician, witness, result |
| CCR | ID, model, circuit, input, output at each step, output voltage, power, alarm, local and remote control, result |
| PAPI | Per unit D/C/B/A: design angle, actual angle, elevation, alignment, intensity, colour, result |
| Sign | ID, location, legend, type, circuit, voltage, illumination, remote status, condition, result |
| Fixture | ID, circuit, location, type, transformer ID, connector, current, condition, colour, photometry, alignment, result |
A typical ITP defines H hold points, W witness points and R review, e.g. cable IR test (W/R), photometry (W/W), PAPI aiming (W/W), final integrated test (hold for client). The actual ITP governs. Keep raw instrument files, photometric data, ALCMS logs and calibration certificates, and make records traceable, dated, signed, linked to equipment and protected from alteration.
HANDOVER AND BASELINE
Final acceptance needs all tests done, failures rectified and retested, photometry and control accepted, documentation complete, punch list closed and airport approval. The handover dossier includes: as-built and circuit drawings, sign schedule, equipment datasheets and manuals, FAT, SAT, electrical, CCR, transformer, cable, photometry, PAPI, sign, ALCMS and standby-power reports, NCRs and punch-list closure, calibration certificates, O&M manuals, spares list (by installed equipment, criticality and manufacturer advice), training records, warranties and asset register. Redlines become final as-built drawings showing the actual installed system.
Commissioning baseline
- Initial insulation resistance, CCR current, voltage and step values
- Photometric output and fixture alignment
- PAPI aiming and photometry
- Sign illumination and electrical condition
- ALCMS configuration, alarm list and communication status
- Example: 600 MΩ at commissioning vs 60 MΩ later is visible immediately
Commissioning proves a new or modified system is correct; maintenance proves it stays correct. Train O&M staff (architecture, CCR, circuits, transformers, connectors, fixtures, PAPI, signs, ALCMS, fault-finding, safety) and operators (control, brightness, alarms, emergency operation, local/remote mode, escalation). Maintenance schedules follow the airport's approved program with manufacturer manuals and applicable ACs.
SAFETY, FOD AND WEATHER
Series circuits can carry hazardous voltages. Near an operational runway, coordinate with ATC, airport operations, airside safety and maintenance control, using work and vehicle permits, radio, FOD controls and the lighting isolation procedure; never assume a runway is unavailable because a test team is on it. Control tools and cable offcuts, remove packing and inspect the work area. Record weather (rain, moisture, temperature, fog, dust, lightning, wind) because it affects insulation readings, optical measurements and safety.
GOLDEN RULES AND MISTAKES
1
Never energise before pre-commissioning is complete.
2
Never rely on continuity alone.
3
Never use uncalibrated equipment for acceptance decisions.
4
Never insulation-test sensitive electronics without the approved procedure.
5
Never accept "light ON" as photometric compliance.
6
Never change PAPI aiming without the approved design.
7
Never repeatedly reset a tripped CCR without identifying the fault.
8
Record actual values, not assumed values; retest after every significant correction.
Final acceptance = technical result + documentation + operational approval.
QUICK REVISION
Remember
- TEST = CHECK · COMMISSION = PROVE THE SYSTEM · FAT ≠ SAT
- Continuity PASS ≠ circuit PASS · ON ≠ COMPLIANT
- Test off → discharge → verify → touch
- One light off: go local · many lights off: go upstream
- FAIL → record → rectify → retest → close
- Accept on the approved requirement, not "it looks okay"
TEST IT. MEASURE IT. COMPARE IT. RECTIFY IT. RETEST IT. DOCUMENT IT. ACCEPT IT. COMMISSIONING = SAFETY + INSTALLATION + ELECTRICAL + FUNCTIONAL + CONTROL + MONITORING + PHOTOMETRY + INTEGRATION + DOCUMENTATION
EXAM / INTERVIEW QUESTIONS
What is AGL commissioning?
Verifying that an installed AGL system is safe, correctly installed, functional, optically compliant, correctly controlled, documented and ready for service.
What is FAT? SAT?
Factory Acceptance Test before shipment; Site Acceptance Test after installation at the airport.
Is FAT sufficient?
No. Site installation and system integration must also be verified.
What is the difference between testing and commissioning?
Testing checks individual parameters; commissioning proves the complete integrated system.
Why test before energising?
To find installation errors, opens, insulation problems and wrong connections before live operation.
Why is insulation testing important?
It verifies insulation integrity and finds leakage or fault conditions.
Is continuity testing enough?
No. A circuit can have continuity and poor insulation, moisture or high-resistance joints.
Why does insulation-resistance trending matter?
Moisture and ageing change values over time; a trend shows deterioration before failure.
What must you do after an insulation test before touching the leads?
Let the circuit discharge fully through the tester or an approved discharge method, verify it is safe, then disconnect. Follow AC 150/5340-26C and the instrument manual.
What secondary-power switch-over times does ICAO Annex 14 set?
Up to 15 s for most lights on CAT I runways. For CAT II/III, key lights such as the inner 300 m of the approach lighting, runway centreline, touchdown zone and stop bars need 1 s. Confirm in Annex 14 Table 8-1 (see Note 05).
Why is photometry required?
A light being on does not prove the optical output meets the requirement.
Why is calibration important?
It makes acceptance measurements traceable and reliable.
Why record actual values?
They are acceptance evidence and the future maintenance baseline.
What should you check if one light is off?
Fixture, secondary connector and cable, transformer, then primary connection.
What if many lights are off?
Control, CCR, primary circuit, primary connectors, transformer section.
CCR trips on energising: what do you check?
Fault indication, input, protection, primary circuit, ground or short fault, circuit loading, diagnostics.
Why test PAPI separately?
It needs specific geometry, aiming, transition and photometric performance.
Why test ALCMS after the field works?
A field circuit can work locally while the control-room command or indication path is wrong.
What is an NCR?
A non-conformance report raised when an item does not meet the approved requirement.
What is a commissioning baseline?
The verified initial condition used for future maintenance comparison.
What are H, W and R in an ITP?
Hold point, witness point and review.
FINAL STUDY TAKEAWAY
Successful commissioning is not proof that the lights switch on. It is documented evidence that the complete installed system performs to the approved design, applicable standards, equipment requirements and airport operational needs.
AGL commissioning = safety + installation + electrical + functional + control + monitoring + photometry + integration + documentation = ready for acceptance.
ENGINEERING & EXPERT NOTES
Write the Acceptance Criteria Before Testing Starts
PreparationAgreed values and methods in advance prevent disputes and make results interpretable. Record who witnessed each test.
Test in Stages, Not Only at the End
SequenceCable, transformer, connector and circuit tests at each stage find faults when they are cheap to fix and before the pavement is closed.
An Electrical Pass Is Not a Photometric Pass
VerificationInclude optical and alignment checks in commissioning. A circuit can be healthy while output is wrong.
Leave a Baseline the Operator Can Use
HandoverTest records, settings and photographs become the reference for every later fault investigation.
REFERENCES & FURTHER READING
These notes are a study aid. Verify details against the primary sources below.
| # | Source | Use it for |
|---|---|---|
| 1 | FAA AC 150/5340-26C – Maintenance of Airport Visual Aid Facilities | Safety, test equipment, CCR, fixtures, PAPI, signs, series-circuit troubleshooting. |
| 2 | FAA AC 150/5340-30J – Design and Installation Details for Airport Visual Aids | Installation and design. |
| 3 | FAA AC 150/5345-10H – Constant Current Regulators and Regulator Monitors | CCR specification. |
| 4 | FAA AC 150/5345-47C – Series to Series Isolation Transformers | Transformer specification. |
| 5 | FAA AC 150/5345-26E – L-823 Plug and Receptacle, Cable Connectors | Connectors. |
| 6 | FAA AC 150/5345-46F – Runway, Taxiway, Heliport and Vertiport Light Fixtures | Fixtures. |
| 7 | FAA AC 150/5345-28H – PAPI Systems | PAPI. |
| 8 | FAA AC 150/5345-44L – Runway and Taxiway Signs | Signs. |
| 9 | FAA AC 150/5340-18H – Standards for Airport Sign Systems | Sign siting. |
| 10 | ICAO Annex 14, Volume I | International aerodrome design and operations: Chapter 8 (electrical systems, secondary power, monitoring) and Chapter 10 (aerodrome maintenance, including visual aids). Check the current edition and amendments. |
| 11 | ICAO Doc 9157 – Aerodrome Design Manual, Part 5 (Electrical Systems) | Series circuits, CCRs, cabling and secondary power guidance. |
| 12 | ICAO Doc 9137 – Airport Services Manual, Part 9 (Airport Maintenance Practices) | Maintenance and inspection practice for visual aids. |
| 13 | AAI AIP India and applicable DGCA CAR aerodrome requirements | Indian requirements and approach/runway lighting data for your aerodrome; confirm the applicable edition. |
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