Renfro's Alaskan Adventures

Cessna 207 Skywagon/Stationair

During cruise flight through an area of mountainous terrain, the commercial pilot became geographically disoriented and selected the incorrect route through the mountains. Upon realizing it was the incorrect route, he initiated a steep climb while executing a 180° turn. During the steep climbing turn, the airplane inadvertently entered instrument meteorological conditions, and the airplane subsequently impacted an area of rocky, rising terrain. The pilot reported there were no mechanical malfunctions or anomalies that would have precluded normal operation of the airplane.

Noorduyn Norseman

The airline transport pilot was on a Title 14, CFR Part 135 passenger flight. The pilot said during cruise flight he heard a loud bang, and the engine started running rough. He said he diverted to the nearest airport, but the engine quit completely, and he was unable to reach the runway. The airplane subsequently collided with terrain, sustaining substantial damage to both wings and the fuselage. An examination of the engine revealed that a locking screw had backed out of one of the anti-vibration counterweights on the crankshaft, scoring the interior back surface of the engine case. The unsecured counterweight then moved from its position in the crankshaft, and was likely struck by the engine's master rod, which shattered the weight, and liberated it from its normal location. The liberated counterweight was struck by internal moving parts, creating several component failures, and ultimately an engine seizure.