(CNN) - The U.S. Navy commander leading the American effort to find Malaysia Airlines Flight 370 said he's "optimistic" about how the search is proceeding.
"We are detecting very continuous pings coming through in a manner consistent with exactly what you'd expect from a black box," Commander William Marks told CNN's Erin Burnett on Friday. "We've ruled out that it was anything natural, or anything from commercial shipping, or anything like that."
Australian Prime Minister Tony Abbott said earlier Friday that search efforts are heading in the right direction. Marks said, "I agree with the prime minister. We're optimistic."