What happened
On March 20, 2011, a Cessna P210N Silver Eagle, registration N50MC, crashed into rocky desert terrain approximately 2 miles south of Barstow-Daggett Airport in Daggett, California. The flight was operating under instrument flight rules (IFR) from John Wayne Airport-Orange County to Henderson Executive Airport. The pilot and her two children, who were the only occupants, sustained 3 fatal injuries.
After departing Orange County, the aircraft was climbing through 9,000 feet when the pilot was notified of light rime icing ahead. The pilot subsequently requested a higher altitude and was cleared to 15,000 feet. During the flight, the pilot reported encountering moderate precipitation and later reported encountering moderate turbulence. Shortly after reporting the turbulence, the aircraft's transmission became partial and final, and air traffic control lost radar contact. Radar data indicated the aircraft began a rapid descent, dropping approximately 9,700 feet in 49 seconds at an average rate of nearly 12,000 feet per minute.
Ground witnesses observed the aircraft in a vertical, spiraling trajectory before an explosion and fire occurred at the impact site.
The investigation
Mechanical examination of the engine, propeller, and airframe revealed no pre-existing failures that would have prevented normal operation. The wreckage patterns were consistent with a ground impact during a left spin while the engine was running.
The investigation focused on the aircraft's modified configuration. The N50MC had undergone several Supplemental Type Certificate (STC) modifications, including a conversion from a piston engine to a Rolls Royce M250 turbine engine and the addition of auxiliary wingtip fuel tanks. These changes increased the aircraft's moment of inertia about the vertical axis by approximately 45% compared to the original production model. Investigators could not determine if the interaction between these multiple STCs affected the aircraft's spin susceptibility or recovery capability.
Toxicological analysis of the pilot's tissue samples detected nortriptyline, a prescription antidepressant, which the pilot had not reported during her FAA medical certification. The presence of this medication was noted, though the degree of impairment could not be determined.
Findings
- The pilot elected to fly into an area with reported moderate to severe turbulence and icing conditions.
- The aircraft entered an aerodynamic spin from which the pilot was unable to recover.
- The aircraft's aerodynamic configuration and weight distribution had been significantly altered by multiple independent STC modifications.
- The increased moment of inertia due to the modifications likely made the aircraft more resistant to spin recovery.
- The pilot had not reported the use of nortriptyline during her medical certification process.