This December 2009 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Aircraft: Beech Bonanza. Injuries: None. Location: Santa Fe, N.M. Aircraft damage: Substantial.
What reportedly happened: During a departure on a cross-country flight, the cockpit filled with an oily smoke. As the smoke began to accumulate, the pilot landed on the only runway he could see through the smoke. The airplane touched down with the left wing low and the airplane went off the side of the runway.
The post-accident investigation determined that an over-pressure condition in the engine’s crankcase resulted in oil being driven out of the crankcase and onto the exhaust system. Smoke entered the cockpit through the heater duct system and gaps in the firewall.
Probable cause: An engine over-pressure condition that resulted in oil getting on the exhaust and producing smoke that entered the cockpit.
For more information: NTSB.gov; NTSB Identification: CEN10LA083.