What happened
During the initial climb phase immediately following departure from runway 09, the crew began retracting the landing gear when smoke entered the cockpit. In response to the visibility issues and potential fire risk, the captain initiated an emergency landing. The aircraft performed a belly landing, skidding for several dozen yards before overrunning the runway and coming to a stop on a railway track.
While 25 occupants managed to evacuate the aircraft without injury, the flight engineer was killed when a propeller blade from the left engine penetrated the cockpit area.
Findings
Investigations determined that the primary cause of the incident was the accumulation of smoke within the flight crew compartment. This volume of smoke caused the captain to become concerned about a potential fire, leading to the decision to land with the undercarriage retracted.
Technical inspections of the airframe and engines identified a fractured rubber hose on the port engine as the sole defect. This component, which connects the rocker box of a lower cylinder to the collector box, allowed oil to leak onto the exhaust collector ring. The resulting smoke was then carried by airflow through the wheel bay and the interior of the center section leading edge directly into the cockpit.