Accident Sequence
The pilot was conducting a three-leg IFR cross-country flight and was on an ILS approach in IMC conditions for the final stop. Radar data showed that the pilot crossed the final approach fix inbound and was approximately 3 nautical miles from the runway threshold when he transmitted that he had "lost an engine." Radar data indicated that the airplane then turned left approximately 180 degrees, after which radar contact was lost.
A witness reported that "the airplane appeared to gain a slight amount of altitude before banking sharply to the left and nose diving into the ground just over the crest of the hill."
Postaccident Examination
Postimpact fuel consumption calculations suggested that there should have been 50 to 60 gallons of fuel onboard at the time of the accident. Examination of the left fuel valve revealed displaced rubber O-ring seals on two Rulon seals. Hydraulic pressure and deflection tests performed on an exemplar fuel valve indicated that the fuel selector valve was in the auxiliary position at the time of impact.
The airplane's Owner's Manual states: "The fuel selector valve handles should be turned to LEFT MAIN for the left engine and RIGHT MAIN for the right engine, during takeoff, landing, and all emergency operations."
No preimpact engine or airframe anomalies that might have affected the airplane's performance were identified.
Probable Cause
The official probable cause was the pilot not following procedures/directives (flying a landing approach with the left fuel selector in the auxiliary position). Contributing factors were the loss of the left engine power due to fuel starvation, the pilot's failure to maintain aircraft control, and the subsequent inadvertent stall into terrain.