Incident Overview
On the return leg of a flight from Turkey Creek to Derby, Western Australia, the pilot encountered dual engine surging. Assessing the surging as due to fuel starvation, the pilot began switching fuel tanks to utilize any remaining fuel. With no resolution, the pilot initiated a MAYDAY call to Brisbane Centre air traffic control, alerted the passenger to the emergency, and told them to brace for impact. During the subsequent forced landing, the right wing of the aircraft hit a tree, causing the aircraft to turn 180° and come to an abrupt stop on the edge of the highway. The pilot sustained serious facial injuries, and the passenger sustained minor injuries. The aircraft was substantially damaged.
Fuel Management
Pre-flight planning is vital to ensure sufficient fuel for all phases of flight. The pilot used the operator’s flight planning software but did not know how to input forecast winds and routinely planned using nil wind. The operator also provided a manual system that would have enabled accurate fuel planning. Taking into account known environmental conditions and the aircraft’s fuel consumption, if the pilot had used available wind data, the flight plan would have identified that the planned flight from Broome to Turkey Creek and return to Derby with required fixed reserve and contingency fuel could not be achieved without refueling en route.
The pilot conducted all flights in the Cessna 310 with the assumption that the auxiliary tanks could not be used for longer than 45 minutes without engine surging and so used them for 40 minutes. While it is likely this behavior was due to a reverse leak in the right auxiliary tank check valve, the ATSB was unable to conclusively determine if this was the reason for the surging on the day of the accident. As a result, the pilot had not intended to use all usable fuel on board, reducing actual endurance. However, this was not reflected during flight planning.
On arrival at Turkey Creek, the pilot reported uneven fuel distribution, with the right auxiliary tank full and less than expected in the right main tank. The ATSB considered possibilities: the pilot did not switch the right main tank to the right auxiliary tank en route, or fuel leaked from the main tank to the auxiliary tank on the ground. Testing indicated a leak through the tank vent outlet bleed return line check valve, but it was unlikely large enough to account for the 40 L discrepancy. It was assessed that it was more likely the pilot did not select the auxiliary tank on the right side during the flight.
Emergency Response and Survivability
The pilot’s response to the emergency included switching fuel tanks, issuing a MAYDAY, and instructing the passenger to brace. The forced landing resulted in the aircraft hitting a tree, causing a 180° turn and abrupt stop. The pilot suffered serious facial injuries; the passenger had minor injuries.
Other Safety Factors Identified
The investigation identified several safety factors related to pilot training and consolidation, operator oversight, organizational aspects, and regulatory oversight. These factors either contributed to the accident or increased aviation safety risk more generally. Topics discussed include defect reporting, legibility and accuracy of aircraft internal placards, survival aspects, operational pressures, and regulatory oversight.