At what time(s) is a test of an installed ELT permitted?

A test of an installed Emergency Locator Transmitter (ELT) is permitted during the first 5 minutes after the hour and for no more than 3 sweeps. This procedure is designed to minimize interference with aircraft operations and ensure the ELT functions correctly without posing a risk to other aircraft or emergency communications.

The specific time window allows operators to communicate the test is taking place, which helps maintain safety in the airspace. The limitation on the number of sweeps—typically limited to 3 available audio pulses—further ensures that the duration of the test is brief and does not disrupt other communications or radar systems monitoring for genuine distress signals.

Understanding this regulation is important not just for compliance with safety codes, but also for the operational integrity of aviation communication systems where emergency signals must be distinctly recognized.