The plane this particular evening was a BAe Jetstream 31 twin-turboprop airliner. The aircraft did not have a cockpit voice recorder or data recorder.
According to reports, all signs were a go as United Express Flight 2415 was scheduled to land at Tri-Cities. The crew aboard did not indicate that there was any danger in landing. The flight was regularly scheduled from Seattle into Paso, with a stop at Yakima.
Upon arriving at Yakima:
A company station agent at Yakima witnessed First Officer McInroe knocking ice off the wings of the aircraft, with the assistance of another company first officer. The station agent asked Captain Roberts whether he wanted his aircraft deiced, but the captain declined.
The plane ultimately crashed into a field just short of the runway in Pasco & burst into flames.
After further investigation, the NTSA determined that ice had built up on the plane's wings during the flight. According to Wikipedia:
The National Transportation Safety Board determines that the probable cause of this accident was the flight crew's decision to continue an unstabilized instrument landing system approach that led to a stall, most likely of the horizontal stabilizer and loss of control at low altitude. Contributing to the accident was the air traffic controller's improper vectors that positioned the airplane inside the outer marker while it was still well above the glideslope. Contributing to the stall and loss of control was the accumulation of airframe ice that degraded the aerodynamic performance of the airplane.
Read more from AP here.