Amateur-built T-51 MUSTANG N151TA accident near Oshkosh, Wisconsin

Probable cause

The separation of an engine cooling hose from the radiator.

NTSB analysis

Shortly after takeoff for a test flight, the pilot noticed that the airplane was not climbing as expected and the engine was slowly losing power. The coolant temperature was 225 degrees and the airplane was only 250 to 300 feet above ground level. During the return to the airport, the pilot heard and felt an explosion behind him and felt a burning sensation on his back. During the forced landing, the right main landing gear collapsed. Examination of the airplane revealed that a cooling line had separated from the radiator behind the pilot during the accident flight. The examination also revealed that the radiator hose line clamp for a different cooling hose was overtightened and not seated properly in its pipe bead. A replacement engine had been installed as a result of a blown head gasket during a previous flight; however, the cooling system was not replaced, and it could not be determined when the clamp was overtightened. An examination of the remaining systems revealed no anomalies.

Text from the NTSB. Open the NTSB docket for CEN12LA530 for the full record.