Incident Description
The aircraft was conducting a night cross-country flight. After leveling off from a descent, the engine suddenly lost power. The pilot managed to restart the engine twice for short durations, but it failed to remain operational. The pilot reported that he had activated the carburetor heat prior to beginning the descent. With the engine inoperative, a forced landing was initiated. During the landing, the airplane impacted trees and subsequently the terrain.
Investigation
The investigating team examined the engine and fuel systems. Despite a thorough inspection, the reason for the power loss could not be identified. A review of icing probability charts indicated that the aircraft was situated in an area where serious icing conditions could have developed at glide power settings.
Subsequent Engine Test
After the event, the engine was tested at less than full power and operated normally.