What happened
On 6 August 2004, a Cessna U 206 G, registration SE-GOP, was performing parachute jump operations near Optand Airport in Sweden. Following a period of refueling, the pilot and six passengers departed the airfield. Shortly after beginning a climb, the aircraft experienced a significant loss of airspeed and the engine began to run irregularly.
In an attempt to manage the malfunction, the pilot manipulated the aircraft controls, eventually placing the plane into a glide and executing a gentle left turn. The engine's performance continued to degrade with heavy vibrations and thumping sounds. The aircraft subsequently struck trees, causing the fuselage to come to rest upside down. An intense fire broke out immediately upon impact. While three passengers managed to escape the wreckage, they suffered severe burns and smoke inhalation. Tragically, the fire became too intense to allow for the rescue of those remaining inside, resulting in 4 fatalities.
The investigation
The Swedish Accident Investigation Board (SHK) examined the wreckage, the engine, and the flight history. Investigators looked into several potential technical failures, including a clogged fuel filter, exhaust system damage, or a leaking fuel pump. While no definitive technical fault was proven, the investigation focused on the pilot's actions during the emergency.
Crucially, the investigation noted that the pilot's recent training had been conducted on a Piper PA-28. The procedures for managing an engine failure in a fuel-injected Continental engine—such as those found in the Cessna U 206 G—differ significantly from those in other aircraft. Specifically, using the electric pump in a manner consistent with Piper procedures could lead to engine flooding.
Findings
- The investigation could not establish a definitive cause for the engine failure.
- Improper application of emergency procedures was a significant concern, as the pilot may have applied training from a different aircraft type to the fuel-injection system of the Cessna.
- The aircraft's maintenance documentation did not include instructions for cleaning the FCU fuel filter, which could potentially lead to obstructions.
- The engine's fuel-injection system requires specific handling during restarts that is contrary to standard general aviation practices.