Incident Overview
Shortly after takeoff, the aircraft's engine lost power. The pilot executed an emergency descent and returned to the airport from which the flight had just departed, landing without further incident.
Preflight Activities
During preflight, the pilot did not use a container to collect fuel from the 'low point' fuel sump located on the belly of the aircraft. This sump is typically checked for contaminants or water.
Post-Accident Inspection
Following the landing, a runup of the engine was performed, and no problems were found with the fuel on board or with the engine itself. However, while the left wing's fuel tank was being removed for repair, ice crystals were discovered at the bottom of the tank.
Conclusion
The investigation did not determine a definitive cause for the power loss, though the presence of ice crystals in the fuel tank was noted.