What is testing?
The activity that measures performance — instrument readings compared with set limits, and recorded.
Testing uses instruments to measure how circuits and equipment perform, then compares each reading with a specified limit. Typical tests cover continuity, insulation resistance, earthing, regulator output current, equipment and control function, and light output where required.
Tests are planned, and the circuit is made safe before measuring: de-energised tests need isolation and earthing, while live measurements such as regulator output current are made only under permit with rated instruments. An out-of-limit result is investigated, fixed and retested, and every result is recorded. Readings taken over time show trends such as falling insulation resistance, which can warn of failure before it happens.
- Plan. Define the reason for the test, the method and limits, and have calibrated instruments ready.
- Make safe. For de-energised tests, isolate, lock off, prove dead and earth; for live measurements, follow the permit and use rated instruments. Control the area.
- Circuits. Measure continuity, insulation resistance and earth resistance. Insulation tests need the circuit isolated, the constant current regulator (CCR) disconnected and the circuit discharged afterwards.
- Equipment. Prove regulator output current, fixtures, signs and control function.
- Compare. Judge each reading against its limit and against earlier results.
- Record. Log results, act on failures and retest after the fix.
Frequently Asked Questions
Q1What is testing in airfield ground lighting?
The lifecycle activity that measures how AGL circuits and equipment perform and compares the results with specified limits. It uses instruments to give numbers, and it is done at commissioning, at set intervals in service and after repairs.
Q2How is testing different from inspection?
Inspection mainly looks at condition, with simple checks. Testing uses instruments to measure performance, such as insulation resistance or light output, and compares the reading with a limit. Inspection can point to where a test is needed, and a test can confirm a suspicion.
Q3What is typically tested?
Circuit continuity, insulation resistance and earthing, regulator output current, equipment and control function, and light output and alignment where required. The tests chosen depend on the asset, the programme and the reason for testing.
Q4Why make the system safe before testing?
Many tests are carried out on circuits that are normally live or carry high voltage and current. De-energised tests such as continuity, insulation resistance and earth resistance need the circuit isolated, locked off, proved dead and earthed, with the CCR disconnected for insulation tests. Live measurements, such as regulator output current, are made only by trained people under permit with rated instruments, and a live loop is never opened. This protects staff and equipment.
Q5What happens when a result is outside the limit?
The cause is investigated, the fault is corrected, and the test is repeated to prove the fix. The out-of-limit result and the retest are both recorded, so the history shows what was found and what was done.
Q6Why keep test records?
Results taken over time show trends, such as insulation resistance slowly falling, before a failure occurs. Records also show the system was proven, and they give maintenance and asset planning evidence for repair or renewal.
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