What happened
Shortly after takeoff, the pilot experienced a simultaneous loss of oil pressure on both engines. The pilot attempted to return to the airport by initiating a left turn. During the landing phase, the aircraft departed from the right side of runway 12. Upon impact, the aircraft collided with two Cessna 150s and destroyed a Piper PA-32.
The investigation
Inspection of the engines revealed significant mechanical failures. Both crankcases had 9x5 inch holes on their tops. Additionally, both engines had two connecting rods that had separated. Review of the engine logbooks showed that the oil had been changed on 10/16/81 using the equivalent of SAE 40 oil.
Findings
The Lycoming Operator's Manual, which was available in the aircraft records, recommends using SAE 20 oil for operation at temperatures below 10 degrees F. The temperature at the time of the accident was -15 degrees F. The use of SAE 40 oil in these conditions likely contributed to fuel exhaustion or loss of lubrication due to viscosity issues.
Safety message
Pilots must ensure that the correct oil viscosity is used for the ambient temperature to prevent engine failure.