What happened
While climbing to cruise altitude, the pilot increased power to the left engine, causing the power lever to become stuck in the full forward position. This malfunction led to an overtemperature and overtorque condition in the engine, prompting the captain to shut down the left engine. Following the shutdown, both primary flight displays lost power, though the crew was able to restore them by resetting the right generator.
Due to the loss of one engine, the crew diverted to a nearby airport to perform a single-engine precautionary landing under visual flight rules. During the descent, the crew experienced confusion regarding their heading because the instrument gyros had been reset, resulting in a 50-degree discrepancy in heading indications. The crew was only able to identify the runway approximately one minute before landing. Although they had declared an emergency and were cleared to use any runway, the crew opted for runway 18.
Upon touchdown, the captain engaged reverse thrust on the right engine, which caused the aircraft to veer to the right. Despite having approximately 5,000 feet of runway remaining, the aircraft departed the runway surface, struck the terrain, and overturned, coming to rest in an inverted position. There were no fatalities or injuries reported in this incident.
Findings
An investigation of the aircraft revealed that a mismatched or incorrectly installed clevis pin by maintenance personnel was the direct cause of the left engine power lever jamming. The loss of directional control during the landing was likely triggered by the application of reverse thrust on the remaining engine and was further complicated by significant crosswind conditions.