According to FAA regulations, an ELT must be inspected in accordance with FAR 91.207(d). Which states that at least once every 12mos the ELT must be checked for:Proper installationBattery corrosionProper operation of controls and crash sensorPresence of a sufficient signal radiated from its antennaYou can test your 121.5 MHz ELTs only during the first five (5) minutes after any hour and you may only activate the ELT for three audible sweeps. If operational tests must be made outside of this period, they should be coordinated with the nearest FAA Control Tower or FSS. If the antenna is removable, an attenuator or dummy load should be used for testing purposes. 406 MHz ELTs should never be activated unless you are in grave and eminent danger. 406 MHz ELTs should only be tested using the “self-test” feature of the ELT or in accordance with an approved maintenance program. For other testing the ELT should be taken to an authorized dealer or test facility. In any case airborne tests are not allowed.
I am the former commander of the Air Force Coordination Center (AFRCC) and I now work for ACR Electronics. As already implied, you can't test the 406 MHz ELT at the top of the hour like the 121.5 without getting a call from the AFRCC. When I left active duty, a small group of us got together and came up with a testing site that allows you test the 406 ELT like you did with the 121.5 called 406Link.com. We recently launched a new website called 406Test.com which satisfies the requirement for initial and annual testing of the ELT. Plus, it doesn’t require any expensive ELT testing equipment. If you want to make sure the 406 MHz ELT is installed correctly and the ELT is transmitting to the satellites use www.406Test.com service. You receive a confirmation SMS text message when you perform a self test of an installed 406 ELT, seconds after you perform the test. By using the service you know (1) that the beacon is transmitting with enough power, (2) the antenna is working and properly installed and (3) the satellites have picked up the signal. Also, you don’t need a screen room because you do it onboard the aircraft. If you have any questions please contact me.