Hawker Beechcraft King Air C90A, Emporia, Kan., Sept. 22, 2007–Following a severe high-frequency vibration in flight and an emergency landing, the King Air pilot found the right elevator trim tab push rod was broken. The NTSB blamed the incident on the improper installation of the trim tab attachment hardware by maintenance personnel, which resulted in excessive wear, fatigue and failure of the push-pull tube. The King Air was operated by Kansas State University