NEWARK, N.J. - Federal investigators say the co-pilot of a Learjet that crashed at New Jersey's Teterboro Airport in May 2017 wasn't authorized to fly the plane.

The jet crashed into office buildings and a parking lot just short of the runway as it prepared to land. Both the captain and co-pilot were killed.

The National Transportation Safety Board said Tuesday the plane's captain violated company procedure by allowing the co-pilot to fly. Investigators also say the crew made numerous mistakes during the short flight from Philadelphia.

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The captain took over the controls in the last 15 seconds of the flight.

Both were killed after the plane missed a required turn and had to bank steeply as it approached the airport.

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