NTSB Factual Report

The student pilot, who was on a solo cross-country flight, was landing at his planned destination. During the landing flare, he added engine power to help arrest the rate of descent, but after making a smooth successful touchdown, he forgot to reduce the engine power. During his attempt to slow the airplane, with significantly greater than idle power being produced by the engine, the pilot lost directional control. After departing the runway, the airplane impacted a wall of boulders that had been erected as a barrier.

NTSB Probable Cause

The student pilot's failure to maintain directional control during the landing roll. Contributing to the accident was the student pilot's improper use of the throttle control.