Flight History
While cruising at 10,000 feet above mean sea level, the aircraft deviated slightly below and above its assigned altitude. Subsequently, it entered a rapid descent and broke apart in flight. Wreckage was scattered over a half-mile area.
In-Flight Fire Evidence
Investigation revealed evidence of an in-flight fire, but the source of the fire could not be verified. A post-crash fire consumed the forward fuselage. A substance identified as PVC-DOP was found on the forward utility door and on the right horizontal stabilizer, both of which had separated from the fuselage. The PVC-DOP had been deposited in a molten state; analysis determined its melting point to be 185 degrees Celsius.
Structural Failures
Examination of the wreckage showed that the horizontal stabilizer had failed into numerous pieces. The wings failed downward, with separation occurring just outside the engine nacelles. Both wing spars exhibited downward deformation.
Preaccident Condition
No preaccident anomalies were found with the airframe or engines.
Pathological Findings
Pathological examinations of the occupants revealed sooting in their tracheas.