The finding was released by the National Transportation Safety Board on Thursday.
Sixteen passengers suffered minor injuries during Flight 345's landing Monday. The plane was coming from Nashville, Tenn.
The NTSB had said Wednesday that the landing gear "collapsed rearward and upward into the fuselage, damaging the electronics bay that houses avionics."
It posted a photo showing the jet's electronics bay penetrated by the landing gear with only the right axle still attached.
Investigators recovered the flight data and cockpit voice recorders on Tuesday. They'll be analyzed by the NTSB.
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