Dash 8 Pilots Faulted in Stick-shaker Incident

 - June 4, 2012, 4:45 PM
The Australian Transport Safety Bureau found the pilots primarily responsible for activation of stick shaker of their QantasLink Dash 8-300 while on final approach.

The Australian Transport Safety Bureau has found the two pilots of a QantasLink Bombardier Dash 8-300 to be primarily responsible for an unstabilized approach that activated the twin turboprop’s stick shaker on final approach to Runway 16 Left at Sydney Airport [YSSY] in New South Wales in March 2011.

The Bureau said both pilots got behind the required checklist duties for configuring the aircraft before commencing the approach. The first officer, who had logged just 26 hours in the Dash 8, was flying the aircraft using the autopilot in instrument conditions when the stick-shaker activated.

Because the aircraft was flying in icing conditions at the start of the arrival, the crew had turned on the increased-reference-speed switch to compensate for necessary airspeed variations related to possible wing contamination. Activation of the switch raises the speed at which the stall-warning sounds. As the airplane left icing conditions, the captain turned off the icing equipment, but failed to notify the first officer and did not reset the increased-reference-speed switch. Because the first officer was not keeping up with the Dash 8’s progress on the approach, the airplane arrived at the final approach fix sooner and faster than normal.

The captain pushed the propeller levers to high rpm to increase drag, while the first officer pulled the power levers to flight idle to attempt to slow the aircraft. As the airplane slowed through 130 knots, with the landing gear and flaps still retracted, the captain said, “airspeed,” to call the first officer’s attention to the issue. Shortly thereafter, as the aircraft further slowed, the stick shaker activated. The captain took control and landed the aircraft without incident.

On rollout, the first officer noticed the incorrectly set reference-speed switch. During a later debrief, the first officer recalled that neither the landing gear nor the flaps were correctly set as the aircraft approached the final approach fix. The captain however, remembered the landing gear as being down, but the flaps being up. Read the complete report.