What happened
The aircraft collided with trees during a forced landing after experiencing a significant loss of power. The flight had been proceeding normally until the student pilot initiated a recovery from a practice stall. As the throttles were advanced to regain airspeed, a violent right yaw developed. When the certified flight instructor (CFI) took control and attempted to recover, both engines suffered a substantial loss of power. A forced landing was executed in a field, but the left wing struck trees, causing the aircraft to be engulfed in flames.
The investigation
Post-accident examination of the left engine revealed no discrepancies. However, significant damage was found on the right engine. The fuel controller fuel line 'tee' fitting was cracked around 50% of its circumference, consistent with ductile overload. Additionally, the turbocharger gasket on the inlet side of the turbine showed leakage around 70% of the gasket area. The aircraft had a documented history of symptoms related to fuel vaporization, which typically subsided when the auxiliary fuel pump was used, as suggested by the engine manufacturer. It remains unknown whether the auxiliary pump was active during this incident.
Findings
The sudden power loss on both engines appears linked to the right engine's fuel system failure. The cracked fitting and leaking gasket likely allowed air into the fuel line or disrupted fuel flow, especially given the aircraft's history of vaporization issues. The violent yaw may have contributed to the mechanical failure or been a symptom of asymmetric thrust during the recovery phase.