NTSB Factual Report

According to the pilot of the Cessna 120, the purpose of the flight was to regain his night currency. While turning onto the final leg of the approach, he thought that the airplane's altitude was higher than normal, so he "slipped" the airplane. While in the landing flare he lost visual contact with the runway. The airplane touched down left of the centerline near the runway edge, impacted a runway sign, and ended up in the inverted position. The pilot reported that he did not experience any mechanical malfunctions with the airplane prior to impact.

NTSB Probable Cause

The pilot's failure to maintain proper runway alignment during landing.