ICAO Lights - Understanding the rules of apron floodlighting an FAQ guide

The ICAO publishes a list of recommendations and not compulsory rules. These recommendations, however, are adopted by local governing national bodies that can convert them into legal requirements. These governing bodies are typically known as ‘Competent Authorities’ (CA) and would usually be a country’s Civil Aviation Authority or their Health & Safety or Standards agencies. As these legal requirements are the responsibility of the local CA, it can choose to exceed any minimum ICAO recommendations if it wishes.

• In the USA, the legal requirements guiding document is Illuminating Engineering Society of North America’s IES RP-37.
• In the UK, it’s the Civil Aviation Authority’s CAP168.
• In Europe, this is covered by European Union Aviation Safety Agency’s EASA CS ADR – DSN.M.750.
• In Australia, it’s the Civil Aviation Safety Authority’s MOS139.

For other examples and to discuss specific national or international requirements, please contact us.

These standards can be found in Annex 14 to the Convention on International Civil Aviation
Aerodromes, Volume I, Aerodrome Design and Operations, Eighth Edition, July 2018.

It recommends the Average Illuminance should be at least the following:

• For aircraft stands:
  • A horizontal illuminance — 20 Lux with a uniformity ratio (average to minimum) of not more than 4 to 1.
  • A vertical illuminance — 20 Lux at a height of 2m above the apron in relevant directions.
• For other apron areas:
  • A horizontal illuminance — 50 percent of the average illuminance on the aircraft stands with a Uniformity Ratio (average to minimum) of not more than 4 to 1

Each aircraft stand needs to be measured independently to guarantee compliance with the requirements because they specifically refer to aircraft stands.

For a MARS stand, that may have several aircraft types using it, you need to design it and take measurements for each type of stand within the MARS stand individually.

Although the requirements call for an Average Illuminance, the minimum levels are also important as they form part of the Uniformity Ratio calculations. The Uniformity Ratio is equally important but is often overlooked during light levels checks. Always make sure the design and actual levels comply with both the Average Illuminance and the Uniformity.

Although it doesn’t expressly say so in the recommendations, it wouldn’t be practical or safe to measure the levels with an aircraft on the stand. So, the stand must be clean and clear when any measurements are taken. The design process should also be done without an aircraft on the stand. However, designers may choose to add a model of the aircraft to show the effect of shadowing.

Yes. You’ll need the following when you’re measuring the apron lighting levels:

• A LED calibrated light meter.
• Either a measuring wheel/stick – to measure the distance between the measuring locations.
• Objects to be used as a marker i.e. traffic cones.
• A photometric results sheet to keep clear records of the measured lux levels.

The light meter, or lux meter as it’s also known, is a very sensitive device. So we recommend:

• You chose a reputable manufacturer’s lux meter – typically with an f1’ value better than 3%.
• Special care is taken to make sure the lux meter is suitable for the application and calibrated within 12 months of usage. This is because the standard calibration of lux meters is made with the CIE Illuminant A (2856K incandescent source) whereas LEDs have a very different spectral response, most commonly with a strong blue peak.
• You remember to select the correct measuring scale before it’s used.

If you’d like any help choosing a lux meter, or how to use it, just let us know

Yes. A Code F stand is so much bigger than the Code C stand, the same approach wouldn’t work. A higher number of measuring points are needed to give more accurate results for larger-sized stands. You’ll find more details about this in our Photometric Guide >

ICAO Annex 14 doesn’t prescribe the specific glare levels that should be adhered to. It does make the following recommendation though:

• Apron floodlights should be located to give adequate illumination on all apron service areas, with a minimum of glare to pilots of aircraft in flight and on the ground, aerodrome and apron controllers, and personnel on the apron. The arrangement and aiming of floodlights should mean an aircraft stand receives light from two or more directions to minimize shadows.

The European Normative EN 12464-2:2014 Light and lighting — Lighting of workplaces Part 2: Outdoor work places Table 5.2 — Airports is generally used to prescribe the Glare Rating limits (RGL) which should be below 50.

When designing apron floodlighting, as well as following the recommendation that an aircraft receives light from at least two directions it also applies to the final aircraft stands on either side of an apron area.

No. They’re very different and their definitions explicitly exclude each other.

An apron is a defined area of land at an airport used for the safe loading and unloading of passengers, mail, cargo. It’s also used for safely fuelling, parking, and maintenance. All of which should happen without interfering with the airport’s traffic. None of these things happen on a taxiway, so they don’t fall under ‘other apron areas’.

Taxiways are included in the definition of Manoeuvring Areas – the part of an airport used for take-off and landing of aircraft, excluding aprons.

The definition of a taxiway is: a specific path at an airport used for the taxiing aircraft that provides a link between one part of an airport and another. This includes:

• The aircraft stand taxi lane – an area of an apron designated as a taxiway and used to provide access to aircraft stands only.
  
  
• The apron taxiway – a part of a taxiway system found on an apron that gives a taxi-route across the apron.
  
  
• The rapid exit taxiway – a taxiway connected to a runway at an acute angle and designed to allow landing airplanes to turn off at higher speeds than are achieved on other exit taxiways to minimizing runway occupancy times.
  
  

It’s worth noting too that the ICAO’s DOC 1957 Aerodrome Design Manual Chapter 13, Apron Floodlighting states that “On taxiways adjacent to aircraft stands, a lower illuminance is desirable in order to provide a gradual transition to the higher illuminance on the aircraft stands.”