Published: Aug 14, 2010 12:30 AM EDT
Updated: Aug 13, 2010 6:49 PM EDT

JUNEAU, Alaska (AP) - A sophisticated beacon was registered to the plane that crashed in Alaska, killing former U.S. Sen. Ted
Stevens and four others, but it's unclear if it was onboard.

If a beacon is properly registered, not only is the distress signal picked up by a control center over satellites but
registration information - like the owner - also comes up.

That's intended to allow officials to try to reach the plane, to help determine the nature of the alert, to rule out whether it's a
false alarm, and to get more detail about where an accident happened.

An official with the National Oceanic and Atmospheric Administration says a system database shows the beacon as
registered to the Alaska plane.

But authorities have said no beacon or alert went off.