406 MHz ELTs Have Tempting Features

You might decide to switch, even if you don't have to.

As the February 1 deadline for satellite surveillance of 121.5 MHz came and went, I admit I was relieved that I was not required to switch to a new 406 MHz ELT. But after reading John Collins' "Avionics" column in the April issue of the American Bonanza Society magazine, I'm tempted to spring for one of the next-generation ELTs; just because they do some cool stuff.

Like all pilots, I don't have a crash landing scheduled for the foreseeable future. But should the unexpected happen, here's what I would have to look forward to with both types of ELTs. First, the 406 has 50 times the transmitting power compared with my old 121.5 unit. According to Collins' article, 121.5 MHz ELTs only logged one save per 1,000 alerts -- that's a lot of false alarms. Even if it works as advertised, my old ELT would require search parties to scour 483 square miles, compared with 30 square miles for a 406 MHz unit. Add a GPS receiver and that area is reduced to .012 square miles. I'm lousy at geometry, but it sounds like they could find me in my back yard.

Because the 406 MHz ELT is digital, it can transmit aircraft-specific data. That means searchers would know who was squawking and could call my cell phone to see if I had tripped the ELT by accident. And if they weren't able to contact me, they could access ATC data to see if I was on an IFR flight plan -- and if controllers had lost communications with me. The combination of low-Earth-orbit (LEO) and geostationary-Earth-orbit (GEO) satellites is impressive. The GEOs can know within a minute if my 406 MHz ELT activates. The LEOs can determine a rough position fix within an hour. And new 406 MHz ELTs all have 121.5 transmitters as well. That's because it's possible to home in precisely on the 121.5 signal; unlike the more modern digital signal. That's all the best of something old and something new.

If you fly your U.S.-registered aircraft in Mexico after July 1, you'll have to have a 406 MHz ELT. Canada and the Bahamas plan to require them starting in 2011 for U.S. registered visitors. For now, the U.S. is leaving it up to aircraft operators to decide whether they want the added coverage. While I'm not rushing out to pay the $500 to $2,500 for a spiffy new 406 MHz ELT, I admit I'm impressed by their capability -- and an updated ELT has earned a pretty high spot on my wish list.

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