Incident Narrative
The airplane was at 2,000 feet MSL on an IFR radar vector for the approach when the engine rpm surged, the oil pressure decreased, and the electronic engine monitor indicated an over temperature condition on the #4 cylinder. The engine began running rough and vibrating. The pilot shut down the engine and declared an emergency as the airplane descended into VFR conditions at 500 feet MSL. A forced landing was executed to a road with transmission lines and trees. During the landing flare and touchdown, the left wing of the airplane struck trees.
Engine Examination
After the accident, the lower area of the fuselage was covered with oil. Examination revealed that a line and B-nut at the turbocharger wastegate were loose. The #4 cylinder was seized and the #4 rod bearing journal was damaged. An engine teardown revealed physical evidence of oil starvation.
Maintenance History
This was the first flight following the annual inspection. On November 8, 1996, the turbocharger had been overhauled and reinstalled. During the last annual inspection on November 19, 1997, the mechanic had welded a patch on the turbocharger outlet elbow.