A helicopter crash in central Alberta that killed one man last year was the result of a faulty part that made its way through the manufacturing process, the Transportation Safety Board has found.
The Bell 212 helicopter was part of firefighting operations northwest of Evansburg, Alta., about 100 kilometres west of Edmonton. The model is a two-blade helicopter that has been in operation since the late 1960s.
At around 6 p.m. on June 28, 2021, the helicopter's pilot was asked to transport three groups of firefighters from the fire area to a staging area located just northwest of Evansburg.
The first two trips went without incident. During the last, the helicopter was approaching a landing area when the chopper's main rotor assembly broke free, causing the aircraft to crash.
The 48-year-old pilot — the only person on board at the time — was killed. A post-impact fire destroyed most of the helicopter.
The TSB released its investigation report on Wednesday, analyzing how and why the main rotor assembly failed.
The first main rotor blade to separate fell to a burned-out bush area about 140 metres southwest of the main wreckage. The second separated with the rotor head assembly still attached; it came to rest 26 metres northeast of the main wreckage.
The investigation found the main rotor hub strap retaining pins — a critical flight safety part — was made from a type of steel that did not meet strength requirements.
The pin failed in flight, causing one of the main rotor blades to separate from the helicopter. That loss caused the remaining blade and main rotor head to separate from the craft.
Working with U.S. authorities, TSB traced the faulty part through the manufacturing process.
The report's findings note:
For undetermined reasons, the quality control inspector at the Fore Machine Company in Haltom City, Texas, did not observe that mixed material was identified in the lot of raw material
A lack of training requirements for hardness testing within standard operating procedures likely contributed to testing being done incorrectly
For undetermined reasons, quality control systems at the Fore Machine Company did not identify the non-conforming main rotor hub strap pins
After the crash, Bell Textron Inc. issued four alert service bulletins requiring a review of technical records for 204B, 205, 205B and 212 helicopter models to determine if there were any more non-conforming rotor pins.
Transport Canada issued a directive mandating compliance with the bulletins as did the U.S. Federal Aviation Administration and the European Safety Administration.