(NBC NEWS) Federal investigators said Sunday that a cockpit voice recorder recovered from Asiana Airlines Flight 214 showed that the airliner’s pilots asked controllers for a “go-around” – another attempt at landing — just 1.5 seconds before the jet crashed at San Francisco International Airport, killing two and injuring scores of others.

National Transportation Safety Board chief Deborah Hersman said at a Sunday news conference that the “black box” flight data recorders also showed there was an attempt to boost airspeed just before the aircraft impacted the sea wall and then slammed into the runway.

There was no evidence in the two recovered “black boxes” that the Boeing 777 was experiencing any problems before the crash on Saturday, Hersman said. The airline’s president said earlier that engine failure was likely not the cause of the deadly incident.

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