Photometric Test Data Analyzer

Compare field intensity readings against the required minimum, with statistics, a status for each fixture and a report.

About this calculator

Enter the minimum intensity from the standard that applies to the light type, then paste your readings. The tool shows the average, spread and lowest reading, and sorts each fixture into pass, investigate or replace against action levels you set. It does not hold the standard's tables, so the required minimum is always yours to enter and cite.

Requirement & Action Levels

Required minimum

Unit

Rule note

Take this from the standard and figure for your light type, category and colour. The default is an example only, not a standard value. If you change the unit, re-enter the minimum, readings and baseline in the new unit.

Investigate below (%)

Replace below (%)

Rule note

Percent of the required minimum. Both are placeholders for your own maintenance rules.

Baseline average, new fixtures (optional)

Rule note

Same unit. If entered, the average is also shown as a percent of new-fixture performance.

Readings

Paste readings (one per line)

Rule note

Use "ID, reading" or just the reading. Lines pasted from a spreadsheet work too. Lines without a number are counted as skipped.

Report details

Project Name (for report)

Light type & standard reference (for report)

Build-up

Readings

—

Valid readings

Average

—

Lowest / highest

—

Spread

—

Standard deviation

Investigate / replace

—

Fixtures in each band

Against baseline

—

Average ÷ new-fixture average

Reading Status

Fixture	Reading	% of required	Status

Calculator #31 | Rev. 1.1 | 23 Oct 2026

Engineering reference tool. The required minimum and action levels shall be taken from the applicable standard and your maintenance procedure.

Method & Reference

How the readings are analysed

Every step is shown so the result can be checked by hand.

1. Percent of required

Each reading is divided by the required minimum you entered.

% = reading ÷ required × 100

2. Status bands

A reading at or above the investigate level passes. Between the replace and investigate levels it needs investigation, and below the replace level the fixture is a replace candidate. The average is banded the same way. A pass below 100 % is tagged "below required", because passing here means above your action level, not that the reading meets the full requirement. For acceptance testing of new fixtures set the investigate level to 100 %.

3. Statistics

Average, lowest, highest and the sample standard deviation are shown. A high spread against the average points to uneven lamp ageing, dirty lenses or aiming differences.

SD = √( Σ (x − mean)² ÷ (n − 1) )

4. Outlier flags

Readings more than 2 standard deviations from the average, and readings above three times the required minimum (the upper limit FAA AC 150/5345-46F puts on a measured average), are flagged for a repeat check, since they often point to a unit, meter or filter error. A single reading well above the minimum is not itself a fault, because intensity is highest near the beam centre. Flagged readings are still counted.

Worked example

Example values only, not a standard.

Item	Value
Required minimum	10,000 cd
Readings	12,000 / 9,500 / 8,000 / 6,500 / 4,000
Average	8,000 cd, 80 %
Bands at 70 % and 50 %	3 pass, 1 investigate, 1 replace
Lowest reading	4,000 cd, 40 %

What this tool does not do

It does not hold the photometric tables, model the beam pattern or judge the measuring method. The required minimum and the action levels come from your standard and maintenance procedure.

Photometric Test Data Analyzer: Frequently Asked Questions

Quick answers on comparing field intensity readings against a required minimum.

What does the Photometric Test Data Analyzer do?

It compares field intensity readings against a required minimum that you enter. It shows the average, spread and lowest reading, and sorts each fixture into pass, investigate or replace against action levels you set. It also produces a PDF report.

Where does the required minimum come from?

You enter it. Take it from the standard and figure for your light type, category and colour. The default on the page is an example only, not a standard value, and the tool does not hold the standard's tables. If you change the unit between cd and kcd, re-enter the minimum, the readings and the baseline in the new unit.

How are the pass, investigate and replace bands decided?

Each reading is divided by the required minimum, times 100. A reading at or above the investigate level passes, one between the replace and investigate levels needs investigation, and one below the replace level is a replace candidate. The average is banded the same way. A pass below 100 percent is tagged below required, so for acceptance testing of new fixtures set the investigate level to 100 percent.

Which statistics are shown?

The average, lowest, highest and the sample standard deviation, where the sum of squared differences from the mean is divided by n minus 1. A high spread against the average points to uneven lamp ageing, dirty lenses or aiming differences.

How are outliers flagged?

Readings more than 2 standard deviations from the average are flagged for a repeat check. So are readings above three times the required minimum, which is the upper limit FAA AC 150/5345-46F puts on a measured average. Such readings often point to a unit, meter or filter error. A single reading well above the minimum is not itself a fault, because intensity is highest near the beam centre, and flagged readings are still counted.

What is the baseline average for?

It is optional. If you enter the average of new fixtures in the same unit, the tool also shows the measured average as a percent of new-fixture performance.

Can you give a worked example?

With a required minimum of 10,000 cd and readings of 12,000, 9,500, 8,000, 6,500 and 4,000 cd, the average is 8,000 cd, which is 80 percent. With bands at 70 percent and 50 percent, three pass, one needs investigation and one is a replace candidate, and the lowest reading is 4,000 cd, or 40 percent. These are example values only, not a standard.

Is the result a final decision?

No. The tool does not hold the photometric tables, model the beam pattern or judge the measuring method. Field readings depend on the instrument, aiming, the point measured and lens condition, so confirm any result near a limit with a repeat reading. The required minimum and action levels shall be taken from the applicable standard and your maintenance procedure.

Important Notice, Disclaimer & Limitation of Liability

Please read before relying on any content on this page or on any result or record produced by it.

Specific to this page: Applies to the Photometric Test Data Analyzer (calculator), including its PDF reports.

Calculated results. Results, tables, charts, status indicators (such as “OK”, “within limit” or “pass”/“fail”), recommended or selected values and the example presets on this page are first-pass planning and training estimates calculated in your browser from the values you enter, using simplified formulas, generic tables and typical values. They do not take account of every factor of a real installation, may contain errors or rounding differences, and are not a design, specification, selection, sizing, procurement or acceptance decision. A competent person must check them against the approved design, the manufacturer’s data and the applicable standard before any use. “Recommended” means an indicative estimate, not an endorsement of any rating, product or supplier.

Photometric content. Intensity, coverage, uniformity and grid values, and any comparison with a photometric requirement, use simplified grids and example data. They are not a photometric test report, a measurement made with calibrated equipment, a calibration, or a finding of compliance or non-compliance with ICAO Annex 14, FAA AC 150/5345 or any other document. Compliance work needs calibrated photometric equipment and the exact tables of the current applicable standard.

Reports, downloads and printouts. PDF reports, CSV files and printed pages produced by this tool are uncontrolled working records generated in your browser. They are not approved designs, drawings, controlled documents, certificates, permits or regulatory records. Calculator numbers, revision labels, dates, project names, signature or approval fields on them are layout only and carry no authority unless made under your own approved document-control system. You must not present an output as an approved, verified or certified document. If you enter personal or confidential information, you are responsible for handling any exported file lawfully, including under the Digital Personal Data Protection Act, 2023.

Your data and third-party services. Calculations run in your browser. Values you type, select or tick, and any report you generate, are not sent to us. We use no advertising or analytics tools on this page. Your browser requests fonts from Google Fonts and icon files (and, on some pages, scripts) from the cdnjs/Cloudflare network, which receive your IP address and basic browser details under their own policies. Please do not include confidential, classified or security-sensitive information in anything you send to us.

Educational reference only. This page is general information for competent, suitably trained and authorised aviation and electrical personnel and for learners. It is not professional engineering, legal, regulatory or safety advice, is not an approved procedure, and creates no professional or client relationship. Values, tolerances, intervals, sequences and examples are generic and indicative; real installations differ by design, make, model, age and condition, and your aerodrome’s approved procedures and the manufacturer’s documents prevail.

Standards and regulations. References to ICAO, FAA, IEC, IEEE, ISO, BIS (IS), DGCA, AAI and other documents are paraphrased summaries for orientation. They are not official text, may be incomplete or superseded, and do not state what any airport, project or regulator requires. Always consult the current official editions and the controlling project specification. Using this tool, or following its output, does not guarantee compliance with any law, standard or approval, and nothing on this page states that any airport, product or project complies or does not comply.

Safety. Series-circuit airfield ground lighting equipment can carry lethal voltages. Treat every circuit as live until it has been isolated, locked out, proved dead and discharged under your aerodrome’s permit-to-work and LOTO procedures and the manufacturer’s instructions. Nothing on this page authorises work on live equipment, bypassing of any safety device or interlock, installation, adjustment, energisation, return to service, a change of operating category (CAT I/II/III), a NOTAM or any certification decision; those rest with the aerodrome operator, the air navigation service provider and the competent regulator.

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Notice v2.9 · 27 October 2026 · Full terms: Legal & Disclaimer

Photometric Test Data Analyzer

Requirement & Action Levels

Readings

Report details

Build-up

Reading Status

How the readings are analysed

1. Percent of required

2. Status bands

3. Statistics

4. Outlier flags

Worked example

What this tool does not do

Photometric Test Data Analyzer: Frequently Asked Questions

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Important Notice, Disclaimer & Limitation of Liability