What is automated photometry in AGL?
Calibrated sensors measure the light each fixture really gives out — logging every value so dim lights are found before they matter.
Automated photometry uses calibrated light sensors and software to measure the output of installed lights, such as their intensity and colour. Each value is logged with the light, its position and the time, and compared with the standards and the airport’s maintenance limits.
A light can be lit and still be too dim, because dirt, ageing, moisture and misalignment all cut output. Measurement shows slow losses that a lamp-out check misses, using the same method every run. The system only measures and compares: an engineer confirms a low reading and decides whether to clean, adjust or replace the light, then re-measures to confirm. It is used within the approved maintenance programme, not in place of it.
- Calibrate. Prepare the sensor and check it against a reference.
- Position. Set up the sensor and list the lights to be measured.
- Measure. The sensor reads each light’s intensity and colour as it moves along them.
- Log. Record each value with the light, its position and the time.
- Compare. Check against the standards and limits, and flag low or off-colour lights.
- Act. Clean, adjust or replace after confirmation, then re-measure to prove the fix.
Checks installed lights in service, against the standards and the airport’s limits, to find the ones needing attention.
Tests a fixture design at full angular detail on a test bench, usually for certification, before it is installed.
Frequently Asked Questions
Q1What is automated photometry in airfield ground lighting?
Measuring the light output of installed lights with calibrated sensors and software, with little manual effort. The system records values such as intensity and colour for each light, tags them with position and time, and compares them with the limits that apply.
Q2Why measure light output, and not just check that lights are on?
A light can be lit and still be too dim. Dirt, ageing, moisture and misalignment all reduce output, and the eye cannot judge it reliably. A check that only finds failed lamps misses these slow losses, which measurement shows.
Q3What does automated photometry measure?
Mainly the intensity of each light, and its colour where the equipment can check it. Some systems also look at beam direction. What is measured depends on the sensor and on the type of light, so the method is matched to the fixture.
Q4How is field photometry different from laboratory photometry?
Laboratory photometry tests a fixture design at full angular detail on a test bench, usually for certification. Field photometry checks installed lights in service, against the standards and the airport’s maintenance limits, to find the ones that need attention.
Q5What can affect the accuracy of the readings?
Sensor calibration and alignment, dirt or water on the lens or surface, ambient and stray light, and the position of the sensor relative to the light. Results are therefore checked against a reference, and a low reading is confirmed before action.
Q6Does automated photometry replace the required checks?
Only if the aerodrome’s approved procedures and the regulator accept it. ICAO Annex 14 and national rules set what must be measured and how often, so automated photometry is used as part of that programme and does not replace it.
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