NTSB Identification: SEA07FA277
14 CFR Part 91: General Aviation
Accident occurred Monday, September 03, 2007 in Mammoth Lakes, CA
Probable Cause Approval Date: 07/09/2009
Aircraft: Bellanca 8KCAB-180, registration: N240R
Injuries: 1 Fatal.

Examination of the accident site revealed that the airplane was on a northerly heading at impact, indicating that the pilot had executed a 180-degree turn after radar contact was lost. Ground scars and distribution of the heavily fragmented wreckage indicated that the airplane was traveling at a high speed when it impacted in a right wing low, near level pitch attitude. A postimpact fire consumed the fuselage, with the exception of its steel frame. The wings were fragmented into numerous pieces. The ELT was destroyed. Damage signatures on the propeller blades and the engine crankshaft indicated that the engine was operating at impact. Examination of the airframe and engine revealed no evidence of any malfunctions or failures that would have prevented normal operation.

Visual meteorological conditions existed in the accident area at the time of the accident. Mean winds at 10,000 feet were from 220 degrees at 15 to 20 knots; some gusts of 25 to 30 knots may have occurred. Moderate turbulence and downdrafts of at least 400 feet per minute probably occurred at the time and in the area of the accident. The magnitude of the downdrafts likely exceeded the climb capability of the airplane, which, at a density altitude of 13,000 feet, was about 300 feet per minute.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:

The pilot’s inadvertent encounter with downdrafts that exceeded the climb capability of the airplane. Contributing to the accident were the downdrafts, high density altitude, and mountainous terrain.