What is approach-light maintenance?
Keeping the approach pattern whole — failed lights found and replaced, lenses clean, aiming held, masts and frangible couplings sound, and the circuit tested before it goes back into service.
Approach-light maintenance keeps the approach lighting serviceable. Failed lights are found and replaced, lenses are cleaned, aiming and levelling are held, and the mast, fixings and frangible coupling are checked. The connector, earth and circuit are tested too, so the pattern a pilot sees is complete, correctly aimed and safe to strike.
A pilot reads the approach pattern as a whole, so a few failures can matter less than the same failures in a row. Results are counted against the serviceability targets for the runway category, and clusters of failures are treated as more serious than scattered ones. The structure matters as much as the light: never strengthen, bridge or replace a frangible coupling with a different part, and keep vegetation clear. See Approach-Light Inspection for the checks and Approach-Light Structures for the supports. The circuit is live until it has been isolated, locked out and proved dead.
- Look. Check the pattern, ideally at night, and record which lights have failed or look dim.
- Isolate. Switch off, lock out and prove the circuit dead before opening any fixture or connection.
- Clean. Clean the lens, check the seals and clear vegetation and obstructions from the light.
- Check. Check aiming and level, the mast and fixings, the frangible coupling, the connector and the earth.
- Fix. Replace failed lights or parts, tighten to the specified torque and test the circuit.
- Restore and record. Energise, confirm the pattern, clear all tools and log the work.
Approach Lighting Maintenance Checklist
- Look. Check the pattern, ideally at night, and record which lights have failed or look dim.
- Isolate. Switch off, lock out and prove the circuit dead before opening any fixture or connection.
- Clean. Clean the lens, check the seals and clear vegetation and obstructions from the light.
- Check. Check aiming and level, the mast and fixings, the frangible coupling, the connector and the earth.
- Fix. Replace failed lights or parts, tighten to the specified torque and test the circuit.
- Restore and record. Energise, confirm the pattern, clear all tools and log the work.
Never strengthen, bridge or replace a frangible coupling with a different part. Check frequencies, serviceability limits, parts and torque depend on the system, the runway category and the manufacturer.
Frequently Asked Questions
Q1What is approach-light maintenance?
Keeping the approach lighting working as designed. It covers finding and replacing failed lights, cleaning lenses, checking aiming and levelling, checking the masts, fixings and frangible couplings, and checking connectors, earth and the circuit, so the pattern a pilot sees stays complete.
Q2What is checked on an elevated approach fixture?
Check the light output and lens condition, the aiming and levelling, the mast and its fixings for corrosion and damage, the frangible coupling, and the base, connector and earth. Check also that vegetation and obstructions are clear of the light and its line of sight.
Q3Why must the frangible coupling be left unmodified during maintenance?
It must break at its designed point if an aircraft strikes the structure. Do not strengthen it, add bracing, grout or fixings across it, or replace it with a different part. Replace a coupling that is damaged, bent or cracked with the manufacturer’s part.
Q4How are failed approach lights prioritised?
Failures are counted against the serviceability targets for the runway category, and several failures close together are treated as more serious than scattered ones. Follow the airport’s maintenance programme and the national standard for the limits and the time allowed to restore the pattern.
Q5What safety steps apply to approach-light maintenance?
Isolate the circuit, lock it out and prove it dead before opening a connection or fixture. Work under the airport’s permit-to-work, manage work at height and ground conditions, and agree the work with air traffic control where the lighting is in use. Where flashers are fitted (MALSR, ALSF), they are capacitor-discharge units: discharge them as the manufacturer instructs before opening a head or cabinet. Test the light, clear all tools and record the work before returning it to service.
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