What do the FAA lighting terms mean?
The FAA and ICAO describe the same airfield, but they do not always use the same words for it — knowing the pairs keeps two documents from talking past each other.
FAA lighting terminology is the vocabulary of the FAA’s Advisory Circulars for airport lighting and visual aids. Many terms match ICAO exactly, such as threshold, touchdown zone lights and stop bar. Others use a different name for the same idea: airport for aerodrome, VGSI (visual glide slope indicator) for the ICAO visual approach slope indicator, REIL for runway threshold identification lights.
The FAA also names its systems with abbreviations: LIRL, MIRL and HIRL for runway edge lights by intensity, and ALSF-2 or MALSR for particular approach lighting systems. ICAO describes approach lighting by generic type. Distances in FAA documents are in feet; the English dimension governs, and any metric equivalent is given for convenience.
- Name the standard. Is the document ICAO Annex 14, an FAA Advisory Circular, or a national rule based on one of them?
- Map the term. Match it to its counterpart, such as aerodrome and airport, or RTIL and REIL, before comparing any numbers.
- Mind the units. FAA documents give distances in feet and ICAO documents in metres.
- Match the category. LIRL, MIRL and HIRL line up with ICAO low, medium and high intensity in idea, but the requirements behind each differ.
- Check the revision. Quote the current AC or Annex amendment, and whether a requirement is mandatory or advisory.
International Standards and Recommended Practices. A State complies, or notifies ICAO of a difference.
FAA guidance on meeting a requirement. Becomes mandatory where a federal grant or airport certification requires it.
Frequently Asked Questions
Q1Is FAA lighting terminology the same as ICAO terminology?
Largely the same in purpose, but not always in wording. Terms such as threshold, touchdown zone lights and stop bar are shared, while others differ: the FAA says airport where ICAO says aerodrome, VGSI for visual glide slope indicators, and REIL for the lights ICAO calls runway threshold identification lights. Check each term before treating two documents as saying the same thing.
Q2What do HIRL, MIRL and LIRL mean?
They are FAA abbreviations for runway edge lights by intensity: high intensity runway lights, medium intensity runway lights and low intensity runway lights. They correspond in idea to the ICAO high, medium and low intensity categories, but the requirements behind each come from different documents.
Q3What are ALSF-2 and MALSR?
They are named FAA approach lighting systems. ALSF-2 is a high intensity approach lighting system with sequenced flashing lights, typically used where Category II and III operations are supported. MALSR is a medium intensity approach lighting system with runway alignment indicator lights, typically used for Category I. ICAO describes approach lighting by generic type rather than by names like these.
Q4What is an FAA Advisory Circular, and is it mandatory?
An Advisory Circular (AC) is FAA guidance on a way of meeting a requirement. It is advisory in itself, but it becomes mandatory where a federal grant or the airport's certification requires it. Equipment is usually specified in the AC 150/5345 series and installation in AC 150/5340-30, so always check which revision applies.
Q5Which standard should a project follow, ICAO or FAA?
The one named in the contract, the regulator's rules or the funding conditions. Many countries base their rules on ICAO, and some call up FAA equipment specifications too. Where both appear, compare them term by term, including units, because FAA documents use feet and ICAO documents use metres.
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