Less than two seconds before their plane slammed into a runway at San Francisco International Airport, the pilots of Asiana Flight 214 asked for a "go around" to try for another landing, government officials said on Sunday. National Transportation Safety Board chairman Deborah Hersman said that investigators aren't looking into problems with the aircraft but are examining whether pilot error led to the crash. The plane "was significantly below the 137 knots" required to safely land, Hersman said. The pilot in charge of landing the plane was "in training" and making his first trip to San Francisco at the helm of a Boeing 777, a spokeswoman for Asiana said. The jet was flying dangerously low just before it hit the tarmac and exploded, throwing passengers onto the runway. Two were killed and 182 were hospitalized because of the crash.