|LEFT-WING HEAVY. A fuel imbalance resulting from icing within the fuel system turned extreme during a March 2009 Pilatus PC-12 accident in Montana.|
Most pilots know what it feels like when an airplane is wing heavy because there’s more fuel on one side than the other. Corrective action may have included switching the fuel selector from right to left or left to right, adding lateral trim, adjusting your control inputs, or reconfiguring a complex fuel system to balance tank quantities. Many pilots view this aspect of fuel-system management as being so routine that there’s nothing that can get you into trouble. A recently completed investigation by the NTSB of an accident in which the pilot and all 13 passengers were killed tells a different story.
The accident occurred on March 22, 2009, at about 2:32 p.m., local time. The single-engine turboprop Pilatus PC-12/45 was diverting to Bert Mooney Airport (BTM), Butte, Mont., when it crashed about 2,100 feet west of runway 33 at BTM. The airplane was owned by a leasing company, and was operating as a personal flight under Part 91. The passengers consisted of three families en route to Bozeman, Mont., for a skiing vacation. Two of the passengers were daughters of a principal of the leasing company. The flight departed Oroville Municipal Airport (OVE), Oroville, Calif., on an IFR flight plan with a destination of Gallatin Field (BZN) in Bozeman. The airplane was operating in visual conditions at the time of the accident.