2012 C-U206 IA Mechanical Failure Non-Fatal Non-Fatal Single-Engine Winterset

C-U206 Non-Fatal Winterset, IA April 1, 2012

The pilot stated that he departed the airport with six parachutists for a jump flight. As the
airplane approached 1,000 feet above ground level, he noticed that the airplane wasn’t
climbing. He checked the engine gauges and noticed that the engine analyzer was flashing
“CHT” and the cylinder head temperature was 454 degrees F. As the pilot pitched the nose
down and turned back to the airport, he heard a muffled “thud” sound and saw white smoke
pour from the engine. As he prepared for a forced landing, four of the parachutists jumped
from the airplane. The pilot then performed a forced landing in a field, coming to a stop near a
dirt berm. An examination revealed a hole in the engine crankcase, near the No. 4 cylinder.
Various pieces of metal, including part of a “quick oil drain plug” were found in the engine oil
sump. The No. 4 connecting rod journal appeared distorted and displayed extensive heat
signatures. The crankshaft journals on either side of the No. 4 rod journals did not appear to be
distorted or to contain the same heat signatures and were coated with engine oil. The rod and
crankshaft bearings were scored. The signatures on the engine were consistent with the loss of
lubricant to the No. 4 connecting rod journal. A reason for the loss of engine oil to the journal
was not found.

Read the NTSB report.