What happened
During the approach to the airport, observers noted an aircraft flying at a low altitude and low airspeed. The left engine was exhibiting signs of malfunction, including audible knocking and sputtering noises, accompanied by the emission of black smoke. Witnesses also observed the aircraft'-s tail shifting horizontally to the right and a slight leftward bank during its flight path. The aircraft eventually struck a group of trees and came to rest in a field located approximately half a mile north of the airport.
Findings
Investigation of the aircraft's engines revealed that the right engine was functioning normally at the time of impact, with propeller blade signatures indicating active power and rotation. In contrast, the left propeller had been feathered. An examination of the left engine showed heavily carbonized spark plugs and soot within the exhaust tubing, suggesting a rich fuel-air mixture.
Investigators identified that the rubber boot connecting the intercooler to the fuel injector servo had become dislodged and partially drawn into the servo. While the securing clamp was loose, the safety wire remained intact and the clamp showed no signs of impact damage. The condition of the boot and clamp suggested improper installation. Although the left engine failed, the investigation concluded that the pilot should have been capable of maintaining altitude and flight using the remaining operational right engine.