406 MHz ELT testing: Be careful.

[Ron Lee]

Apparently the SARSAT system picks up plenty of maintenance/testing ELT signals. The testing of 406 MHz ELTs is reportedly different than the top of the hour five minute window I recall for 121.5 MHz units.

Ideally someone with a 406 MHz ELT can read the manual and post the testing procedure here. IF you have someone doing an annual/condition inspection, advise them of proper testing procedures.

And please: REGISTER your 406 MHz ELT (PLB/EPIRB). That way they can call to verify that you are not in a distress situation.

The fewer false alerts occur, the better your chance of a speedy response when you really need it.

[n5lp]

Originally Posted by Ron Lee

Apparently the SARSAT system picks up plenty of maintenance/testing ELT signals. The testing of 406 MHz ELTs is reportedly different than the top of the hour five minute window I recall for 121.5 MHz units.

Ideally someone with a 406 MHz ELT can read the manual and post the testing procedure here. IF you have someone doing an annual/condition inspection, advise them of proper testing procedures...

From the ACK E-04 manual:

"During the self test, the ELT transmits on 121.5 Mhz for 1 second, (3 audio sweeps) then transmits a 406 Mhz test burst for 550 ms then returns to the armed mode."

"You must perform a self test (with the remote panel self test button) every three months to verify the ELT is functioning properly."

There is no mention of when to do the test. Since satellites are no longer monitoring 121.5, perhaps it doesn't matter when the test is done if you are not in a place where ATC can hear 121.5? Or maybe a 1 second burst won't worry anyone? I have wondered about this myself as the mandatory self test is considerably less convenient if it is necessary to do it in the old 5 minute time window every hour.

For the annual test which includes the G switch test, the manual does say to do it between the hour and 5 minutes after, "as per FCC requirements." There is an additional note for the G switch test. "As soon as you hear the tone immediately turn the main switch on the ELT to the Off position. The ELT when activated transmits on 121.5 Mhz for approximately 50 seconds before a 406 Mhz burst is sent to the satellites. This is a live burst which will immediately notify the COSPAS/SARSAT system that there is an emergency. It is imperative that you do not allow an activated ELT to transmit for more than 30 seconds during G switch testing"

See ELT UPDATE?LIMIT YOUR 406 MHz TESTING TIME at http://www.faa.gov/about/office_org/...edia/mar06.pdf

[Canadian_JOY]

Testing should still be done in the first five minutes of the UTC hour, irrespective of 121.5 or 406MHz.

Each ELT will have its own test procedures outlined in the installation or operator's manual - follow those procedures.

NOTE: When 406MHz ELT's transmit their test data burst it is encoded with some digital bits flipped to tell SARSAT that it's a test. If you leave the unit on for more than 49 seconds a valid emergency signal will be sent.

At a generic level, for testing 406MHz ELT's it's advisable to ensure that you have our aircraft VHF comm tuned to 121.5MHz, the squelch broken so you hear static (confirm you're hearing static - it's not a good idea to initiate ELT self test and then discover your headset isn't plugged in!), and that ambient noise around the aircraft is relatively low. This way you will be able to hear not only the three brief tone sweeps on 121.5, but you will also be able to hear the ELT activation buzzer (this buzzer is a mandatory requirement for TSO C126 ELT's - so you can hear the ELT is activated from inside or outside the airplane, without ships power applied).