What happened
While flying from Tofino to Vancouver, a Cessna 208B experienced a total engine failure at 9,000 feet. The pilot, attempting to reach Port Alberni Regional Airport, began a glide that eventually required an emergency landing on a logging road. During a steep turn to avoid terrain, the aircraft struck trees and crashed approximately 11 nm south-southeast of the airport. The accident resulted in three fatalities and five serious injuries.
The investigation
Investigators examined the PT6A-1s engine and found that all 58 blades in the compressor turbine section had broken. Metallurgical analysis revealed that a single blade failed due to an overstress rupture following the growth of a fatigue crack, which originated from a metallurgical anomaly. This initial failure caused a chain reaction of impact damage to the remaining blades and led to the compressor seizing.
Technical reviews also noted that the aircraft's GPS database was more than seven years out of date, limiting the pilot's ability to identify suitable landing sites. Additionally, while the engine met certain reliability standards, the operator was not processing engine trend monitoring data at the required intervals.
Findings
- The primary cause of the engine failure was a compressor turbine blade failure resulting from a fatigue-induced crack.
- The pilot's ability to reach a safe airfield was hindered by the aircraft's position, the lack of terrain awareness equipment, and the need to maneuver to avoid instrument meteorological conditions.
- The aircraft lacked modern terrain awareness and warning systems (TAWS) that could have assisted in identifying obstacles during the emergency.
- Existing training standards for single-engine instrument flight rules (SEIFR) did not specifically require practice for forced landings under instrument conditions or in mountainous terrain.