On December 10, 1997, a Beech 1900C (registration N79GL) was involved in an aviation accident near Rockford, IL. Investigators recorded the probable cause as: improper installation of aileron cables by the maintenance personnel, inadequate inspection by the company's maintenance personnel of maintenance performed, and inadequate preflight by the pilot. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 8 related events involving the same aircraft type or operator are linked below.
During a maintenance flight check, the pilot observed aileron movement but did not notice incorrect travel. On rotation, left wing dropped; aileron input had no effect. The airplane struck the runway edge and a taxi sign. Investigation revealed misconnected aileron cables at turnbuckles.
Event Description
The airplane had recently undergone refurbishment and required a maintenance flight check before release. The pilot conducted a preflight inspection, checking the flight controls for freedom of movement. The pilot observed aileron movement in the up and down directions but did not notice that the movement was incorrect. After using normal takeoff procedures, during rotation, the airplane’s left wing began to drop to the left. The pilot applied right aileron input, but there was no effect. The airplane subsequently struck the left edge of the runway in a left-wing-low attitude, and the left wing impacted a taxi sign.
Examination Results
An examination of the airplane revealed that the aileron cables were incorrectly connected at the turnbuckles in the wheelwell. The aircraft maintenance manual contained the following warning: "Visually check to assure that aileron travel responds properly to the control wheel movement. When the control wheel is turned right, the right aileron should move up and the left aileron should move down."