Incident Overview
A pilot reported that after takeoff, dense white smoke began to fill the cockpit, appearing to originate from beneath the instrument panel. The instruments indicated normal operating ranges, but the smoke became so thick that visibility inside the cockpit was reduced to a few inches. A passenger in the right front seat, who was also a pilot, assisted with navigation back to the airport.
Landing and Nose Gear Collapse
The aircraft was landed downwind on Runway 20. Following touchdown, the nose gear collapsed.
Examination Findings
A post-incident examination revealed that a turbocharger exhaust coupling had failed, allowing hot exhaust gases to escape into the engine compartment. The oil pressure hose line subsequently melted, spraying oil onto the turbocharger. The oil mixed with the hot gases and ignited. The resulting smoke entered the cockpit through the vent beneath the instrument panel.
Examination of the nose gear showed that the gear down lock springs had been damaged by the fire, which allowed the nose gear to collapse during landing.
Probable Cause
The probable cause is the failure of the turbocharger exhaust coupling, leading to a fire that produced dense smoke in the cockpit and damaged the nose gear down lock springs, resulting in the nose gear collapse after touchdown.