What happened
During an ILS localizer approach, the pilot reported a loss of oil pressure in the engine. This loss of pressure led to the failure of an engine connecting rod due to insufficient lubrication. The crew subsequently attempted an emergency landing, during which the aircraft crashed into trees.
The investigation
An inspection of the aircraft following the crash revealed that an oil hose located between two oil coolers had become disconnected. The investigation determined that the hose had vibrated free from a fitting, allowing oil to be pumped overboard. While the other oil hoses remained securely fastened, it was noted that the aircraft had recently undergone service involving the installation of new flexible oil hoses.
The company mechanic had not finished the installation of these new hoses before leaving work for the day, deferring the completion of the task until the following Monday. Although the pilot reportedly performed a leak check on the oil hoses prior to the flight, this check was not documented in the maintenance records.