Two airliners were one minute from colliding when one of the planes turned away from the other over the Caribbean this week, federal authorities said Friday. The National Transportation Safety Board said it is investigating an incident in which a Delta Air Lines flight and a Russian-registered passenger jet were heading toward each other north of Puerto Rico when cockpit alarms went off. The NTSB said the pilot of the Russian plane, a Transaero Boeing 737, descended 200 feet to 300 feet to avoid Delta Flight 485. The planes were at the same altitude, 33,000 feet over open ocean, and were "60 seconds apart from occupying the same airspace," said NTSB spokesman Peter Knudson. Knudson said the agency had too little information yet to know whether the planes would have collided had evasive maneuvers not been taken, or if they would have narrowly missed each other.