Final answer:
A 406MHz ELT should be tested during the annual aircraft inspection and after a new battery installation or impact. The test should check functionality, battery life, and signal strength while avoiding interference with search and rescue operations.
Step-by-step explanation:
A 406MHz Emergency Locator Transmitter (ELT) should be tested in accordance with the guidelines provided by the manufacturer and the regulations of the aviation authority under which it operates. However, for most ELTs, the general recommendation is that they should be tested during the annual aircraft inspection and after installing a new battery or if the ELT has been subjected to a shock or impact. Content loaded on how and when should a 406MHz ELT be tested typically includes checks for the operational functionality battery expiration date, and signal strength which should be done without triggering a false alarm.
It is important for the test to be conducted in a way that does not interfere with search and rescue operations; therefore, many aviation authorities recommend testing within the first five minutes after the hour and for a duration of no more than three audio sweeps. Proper maintenance and testing of the ELT are critical for ensuring its reliability in the event of an emergency.