Flight and Engine Problem
A pilot and two observer/trainees were conducting a flight along the Lake Michigan shoreline. Approximately 23 minutes after departure, while approaching to land at Chicago, the pilot reported an engine problem of unknown origin.
Forced Landing Attempt
The pilot attempted to land in a parking lot at a water filtration plant. After clearing the roof of a building, the aircraft turned and subsequently collided with a retaining wall at the edge of the parking lot.
Injuries
Both observer/trainees were fatally injured. The pilot was seriously injured and was unable to recall the events of the flight.
Fuel System Examination
Post-accident examination revealed the fuel selector was positioned to the left fuel tank, which remained intact. Less than 1 gallon of fuel was estimated to be remaining in the left tank. The aircraft fuel tanks had a total capacity of 50 gallons, of which 13.5 pints of fuel was considered to be unusable (less than 1 gallon per tank). Approximately three hours after the accident, no odor of fuel was noted beneath the ruptured right fuel tank.
Refueling History
No witnesses or records were found to indicate the aircraft had been refueled before the flight.