When may an emergency locator transmitter (ELT) be tested?

• A. Only on the hour
• B. During the first 5 minutes after the hour
• C. At any time
• D. During maintenance

Answer: (B)

Testing an ELT is allowed only during the first five minutes after the hour. This narrow window helps prevent interference with real distress signals and reduces the chance of false alarms in the search-and-rescue network that monitors ELTs (including the 406 MHz COSPAS-SARSAT system). By conducting a test in that specific time frame, it’s clear to monitoring stations and services that the signal is a test, not an actual emergency. Outside of that window, a test could be mistaken for a real activation and trigger unnecessary emergency responses. Maintenance testing may occur as part of servicing, but the standard in-flight testing window is the first five minutes after the hour.