While the bulb is rarely the problem. The Ground crews swap it anyway. Nine times out of ten, the real fault sits upstream — a regulator drifting out of tolerance, or a joint in the series circuit that’s been degrading for weeks without anyone catching it.

Why the Fixture Gets Blamed First

Makes sense, actually. A dim light is visible. A failing constant current regulator isn’t, not until it’s bad enough to take out half a circuit at once. The Airports that skip regular CCR testing tend to find out the hard way, usually mid-fog, when visibility’s already low, and three lights on one loop go dark together.

Airport runway lights runs in series, not parallel. And standard building electricians get tripped up by this constantly. One CCR pushes fixed current through an entire string of fixtures. Older ICAO setups run around 6.6 amps on these loops. Each fixture has its own isolating transformer built in — that’s what keeps one dead lamp from killing the whole line.

Airfield lighting control systems Aren’t Just an On/Off Switch

There’s brightness stepping to think about, too. Five levels, sometimes seven. Fog needs one setting, dust storms another, monsoon haze somewhere else entirely, depending on the region.

BILDAL Electricals runs fixture design and control panel design through the same process, so the numbers actually match before a single unit ships. Sounds obvious. while isn’t always practiced. We have come across installations where the fixtures came from one AGL supplier and the CCR from a completely different one — current draw ended up off by close to 12%. It doesn’t sound like much until an FAA or DGCA audit flags it and the whole certification get held up.

Not All Runway Lights Do the Same Job

The threshold lights aren’t touchdown zone lights. And taxiway centerline lights aren’t either. Different beam angles. Different colour temperatures. ICAO Annex 14 spells out exact tolerances for each, and getting even one beam spread wrong turns a clean guidance line into glare that a pilot has to squint through.

Inspection reports catch this fast, usually before anyone’s even checked whether the wirings at fault.

Elevated Fixtures vs Inset — It Depends on Traffic

Smaller regional airstrips are elevated. Cheaper. Easier to service when something breaks. Busier runways can’t get away with that, though — constant wheel loads chew through elevated fixtures fast, so inset units end up being the only practical option once traffic climbs past a certain point.

 

 FAQs

What does a constant current regulator actually do?

Keeps the current fixed across a series circuit. Every fixture on that loop gets equal brightness as a result.

Are runway lighting equipment the same across every runway category?

Not even close. CAT II and CAT III demand tighter photometric tolerances than a basic CAT I setup.

Is it possible to upgrade a control system without touching the fixtures?

Often, yes — as long as the existing fixtures are already ICAO-compliant and the CCR output lines up. Full replacement only becomes necessary when the load math stops working.