Incident Overview
During en route flight, the pilot observed oil streaming from the left engine cowling and subsequently shut down the left engine. Approximately 3 miles from the intended destination, the right engine experienced a total loss of power. The pilot executed a forced landing onto a highway.
Post-Accident Examination
Examination of the airplane, conducted 50 minutes after the accident, revealed that both wings had separated outboard of the engines. No fuel or fuel odor was present in or around the wing fuel tanks. The fuselage fuel tank, which remained intact, yielded approximately 1.5 gallons of fuel when drained.
Engine Inspections
Inspection of the left engine disclosed a hole burnt through the number 6 piston, with damage characteristic of detonation. The right engine underwent a test run, which did not identify any pre-impact discrepancies that would have prevented normal operation.
Fuel System Analysis
The airplane's total usable fuel capacity was 165.5 gallons. The flight had been ongoing for about 2.5 hours since the last refueling, with an estimated fuel consumption of 122.5 gallons. The aircraft was equipped with a fuel flow indicating system; when powered after the accident, it indicated 40.5 gallons of fuel remaining and a total usage of 124.1 gallons since the last refueling.