Flight control system event, Bankstown, New South Wales, Embraer EMB 110-P2 Bandeirante

On 1 September 2005, the crew of an Embraer EMB110-P2 (Bandeirante) aircraft, registered VH-OZF, was conducting a private flight under the visual flight rules from Bankstown Airport to Camden, NSW. At 1343 Eastern Standard Time, on the initial climb from runway 11 Left (11L), the pilot in command (PIC) experienced excessive nose down pitch control forces.

The PIC attempted to correct the pitch force with the manual elevator trim wheel and electric trim, but the trim did not move. The copilot assisted by applying back pressure to his control column and observed that the elevator trim wheel was in the full nose down position. The pilots were unable to maintain altitude and the aircraft descended from approximately 470 to 150 ft.

The PIC reduced engine power and the airspeed reduced. The copilot applied significant force to the elevator trim wheel and the wheel released from the full nose down position. The pilots regained control and landed.

The investigation found that the left yoke-mounted trim switch did not to return to the neutral position, when operated and released, due to a sticky substance binding the levers. It also found that the elevator electric trim servo mechanical clutch did not release at the specified setting due to a lack of maintenance.

The circumstances of this event were consistent with an electric trim runaway occurring during or shortly after take-off. The investigation established that the trim runaway was probably due to the non return of the switch from the nose down position or an unidentified electrical fault.

The pilots reported that they were unable to pull the electric trim circuit breaker, in accordance with the manufacturer’s procedure, because they were unable to release the control column.

As a result of the investigation the operator and manufacturer initiated a number of safety actions.