What is inside an airfield light fixture?
An exploded view pulls the fixture apart along one centreline, in the order it goes together, so each part can be seen on its own: what it is, where it sits and what it does.
A finished airfield light looks like a single sealed unit. Inside, it is a small stack of parts, each with one job. An exploded view separates that stack so the parts, and the order they fit together, can be read at a glance.
1Read it along the axis
All parts are drawn on one centreline. The lens is at the top, where the light leaves, and the base is at the bottom, where the fixture meets the base can. Dashed lines show where each part sits once assembled. The gaps are for clarity only; in the real fixture the parts are pressed together and sealed.
2Group the parts by job
The lens, optics, LED module and driver make and shape the light. The gasket, internal wiring and secondary lead keep water out and carry power in. The housing and base hold everything and carry the loads, and the fasteners and frangible coupling fix the fixture in place and, on elevated products, let it break away if struck.
3Use it to find the part to check
Moisture behind the lens points to the gasket or lens joint. A dark fixture points to the driver, LED module, wiring and connector or, on a series circuit, the isolation transformer and its connection. A wrong beam points to the optics or the way the fixture is aligned. Isolate the circuit and follow the site’s lock-out and tag-out procedure before any fixture is opened.
| # | Part | Group | What it does | Learn more |
|---|---|---|---|---|
| 1 | Fasteners | Fixings | Screws and a retaining ring that clamp the lens and seal down | Open entry |
| 2 | Lens | Light path | Window that passes and shapes the light and protects the optics | Open entry |
| 3 | Gasket | Seal | Compressed between lens and housing to keep water and dirt out | Open entry |
| 4 | Optics | Light path | Prism or reflector that forms the required beam | Open entry |
| 5 | LED module | Light path | The light source; a lamp sits here in lamp-based products | Open entry |
| 6 | LED driver | Power | Conditions the supply to give the LEDs steady current | Open entry |
| 7 | Internal wiring | Power | Carries power from the secondary lead to the driver and light source | Open entry |
| 8 | Housing body | Structure | Holds all parts in position, seals them and carries heat and load | Open entry |
| 9 | Base and frangible coupling | Structure | Fixes the fixture to the base can; the coupling breaks away if struck (elevated products) | Open entry |
| 10 | Secondary lead and connector | Connection | Leaves through a sealed entry and plugs into the isolation transformer secondary | Open entry |
AGL Light Fixture Selection
Fixture selection starts with the position and the standard, because that decides whether the light is elevated or inset; see Elevated versus Inset Fixtures and Runway Fixture Selection. The exploded view then shows what to compare inside a fixture: the lens, optics, LED module and driver that make and shape the light; the gasket, wiring and secondary lead that seal and power it; and the housing, fasteners and frangible coupling that hold it and, on elevated products, let it break away if struck.
Frequently Asked Questions
Q1What is an exploded view of an airfield light fixture?
A drawing that pulls the fixture apart along one centreline so every part can be seen on its own, in the order it fits together. Dashed lines show where each part sits when assembled.
Q2In what order do the parts of a fixture fit together?
By position along the axis, from the bottom up: base and frangible coupling, housing body, internal wiring, LED driver and LED module, optics, gasket, lens and finally the fasteners. The secondary lead leaves through the housing's sealed cable entry. Lamp-based and inset products differ in detail, and the usual order of work is set out in the Fixture assembly sequence entry.
Q3Why use an exploded view when maintaining a fixture?
It shows which part to suspect for a given symptom, which spare to order and the order in which to open and re-seal the fixture. Always isolate the circuit and follow the manufacturer's instructions and site safety rules before opening a fixture.
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