Accident Sequence
Weather conditions at Esperance were fine with no cloud, visibility exceeding 30 km, and a northwest surface wind of 5 to 10 knots. The aircraft entered the circuit on a left downwind leg for Runway 29. The pilot lowered flaps in stages on downwind and extended landing gear before turning onto base leg. This configuration with an airspeed of 133 knots was maintained until after the aircraft straightened onto final approach.
At 1100 feet, the pilot considered he was at decision height and committed to land. He selected full flaps and reduced airspeed to 115 knots. As he retarded the power levers, the right engine flamed out. The pilot reported sensing the failure and checked engine instruments while reopening both power levers; torque and fuel flow for the right engine were zero. He briefly considered retracting gear and flaps but decided against it. Left engine power was increased to maximum available (940°C ITT) then adjusted to normal maximum (923°C ITT). The right propeller was feathered.
During this period, the aircraft banked right and turned away from the runway. Airspeed reduced and rate of descent increased. The pilot applied full left rudder and aileron but could not maintain runway heading, even though airspeed was above the minimum control speed of 94 knots. It became evident the aircraft would land short among trees to the right of the approach path. The pilot abandoned efforts to regain the normal approach and allowed the aircraft to turn further right toward a large clearing. Just before touchdown, he observed a power pole and turned further right to avoid it. During this turn, the right wing tip struck the ground. The nosegear then impacted heavily and collapsed. The aircraft slid and bounced across the ground for 188 meters before coming to rest.
Fuel from ruptured lines ignited under the left engine. The fire developed slowly, and the occupants evacuated in an orderly manner. By the time the fire brigade arrived from Esperance township, the fire had spread and consumed most of the aircraft.
Probable Cause
The right engine flamed out due to fuel starvation caused by failure of a spur gear in the fuel control drive train. Five teeth had broken off, and the remaining teeth were badly worn. The failures and abnormal wear resulted from looseness of the torque sensor housing that mounted the spur gear, allowing misalignment. The housing had likely loosened due to vibration, as its natural frequency was close to some frequencies generated by the engine during normal operation. Contributing factors included that the natural frequency of the torque sensor housings on the engines fitted to VH-SWO were susceptible to vibration frequencies generated during normal operation; that vibration loosened the torque sensor housing on the right engine, leading to misalignment, gear failure, and fuel starvation; that the engine failed when the aircraft was in a landing configuration that precluded a successful continuation of the approach; and that the landing procedure used by the pilot was in accordance with the operator's Company Operations Manual, which did not appreciate the poor performance and handling difficulties of the Swearingen SA226TC in the event of an engine failure in the landing configuration.