How does ICAO classify airfield lighting?
A light is never described by one label — it is placed by what it does, which runway it serves, how bright it is and how it is fitted.
ICAO lighting classification is not one list. Annex 14 describes a light along several axes at once: its function, the type of runway it serves, its intensity, and how it is installed and operated. The requirement that applies is found where those descriptions meet.
The runway type does most of the work. A non-precision approach runway is served, where physically practicable, by a simple approach lighting system of not less than 420 m, while a precision approach runway has a longer system, typically 900 m, and the Category II and III system adds red side row lights in the inner 270 m.
- Name the function. Approach, runway, taxiway, apron or visual approach slope: this picks the right part of Annex 14.
- Name the runway type. Non-instrument, non-precision or precision CAT I, II or III decides what lighting the runway needs.
- Name the intensity. Low, medium or high, matched to the runway type and the visibility it is used in.
- Name the installation and mode. Elevated or inset, fixed or flashing.
- Find the requirement. Look it up in Annex 14 and check whether it is a Standard (shall) or a Recommended Practice (should).
Simple approach lighting, not less than 420 m. Lighter, simpler guidance for a runway used in better visibility.
Longer system, typically 900 m, with extra bars and, for CAT II/III, red side rows in the inner 270 m.
Frequently Asked Questions
Q1How does ICAO classify airfield lighting?
There is no single scheme. In practice a light is described along several axes at once: its function (approach, runway, taxiway, apron, visual approach slope), the type of runway it serves, its intensity category, and how it is installed and operated. Annex 14 sets requirements for each combination, so a light is classified by reading all of them together.
Q2What is the difference between non-precision and precision approach lighting?
A non-precision approach runway is served, where physically practicable, by a simple approach lighting system, not less than 420 m long. A precision approach runway has a longer, more elaborate system, typically 900 m, and the Category II and III system adds extra bars and red side row lights in the inner 270 m. The longer system gives the pilot more visual guidance in lower visibility.
Q3What do low, medium and high intensity mean?
They are categories of light output matched to the runway type and the visibility in which it is used. High intensity lighting is typical on runways used in low visibility, and low intensity on simple, visual runways. The actual light output is set by the photometric curves in Annex 14 Appendix 2, so measure against the curve, not the category name.
Q4Is ICAO classification the same as FAA classification?
No. The FAA uses its own light classes and specifications, such as the L-850 series of runway light fixtures, and its own category names. The two systems overlap in purpose but not in wording, so check which standard a project follows before comparing lights.
Q5Why does the classification of a light matter in maintenance?
It decides which requirements the light must meet. Precision approach runways carry tighter serviceability and reliability expectations than visual runways, and the intensity category decides what to measure and what result is acceptable. Check the requirement in Annex 14 and your national rules, and confirm whether it is a Standard (shall) or a Recommended Practice (should).
See It. Understand It. Then Learn How to Engineer It.
Recognising an AGL system visually is the first step. The next step is knowing how to design, install, test, commission and maintain them correctly.
Build Practical AGL Engineering Skills
Go deeper with structured training from Precision AGL Academy, covering:
Learn how each light, sign and circuit works as part of a complete airport lighting system, not just as an isolated diagram.