Egypt Air Flight 804: 'Black box' signals detected, French investigators say

Authorities hope to locate the data recorders, so a specialized vessel managed by the Deep Ocean Search company can then retrieve them. That vessel is set to join the search team within a week, the investigative committee said.

So far, search teams have found small pieces of debris, victims' remains and personal effects from the plane. They haven't found the aircraft's fuselage.

Analyst: Searchers are nearing wreckage

Detecting the beacon is a sign that searchers are closing in, CNN aviation analyst Mary Schiavo said.

"That means they're probably within one to three miles (of the black boxes)," she said. "That is the distance that these beacons can broadcast, so they are literally almost on top of them."

And it's likely, Schiavo said, that the recorders will be with the bulk of the wreckage from the plane.

"Hopefully they have finally got the right beacon, the right location, and soon we'll have answers," she said.