What happened
During a period of regulatory uncertainty regarding pilot certification, a skill-test was being conducted for a new first officer candidate at Bergen Airport Flesland. The flight involved an SA226-T(B) Merlin operated by Helitrans. The weather conditions during the testing period were characterized by low ceilings, rain, and significant turbulence.
During a previous demonstration of slow flight, turbulence had triggered the stick pusher. To prevent further nuisance activations, the commander had pulled the circuit breaker for the Stall Avoidance and Stability Augmentation System (SAS). This circuit breaker was not reset prior to the flight in question.
During the skill-test, the examiner requested a demonstration of slow flight up to the first indication of a stall. As the crew performed the maneuvers in IMC, they lost control of the aircraft's airspeed and attitude. Despite applying full power, the airspeed dropped to approximately 30 kt, and the aircraft developed a descent rate of roughly 10,000 ft/min. The aircraft impacted the sea in a near horizontal attitude approximately 37 seconds after control was lost. The accident resulted in 3 fatalities.
Findings
An investigation into the crash included a Computational Fluid Dynamics analysis of the aircraft's external sensors and antennas. While these modifications were found to reduce overall performance, they did not significantly degrade stability or control during slow flight.
Investigators concluded that the failure to reset the SAS circuit breaker was a critical factor. The investigation also highlighted deficiencies in training regarding stall recovery techniques, specifically the tendency to prioritize altitude retention over breaking the stall by reducing the angle of attack. Consequently, safety recommendations were issued to the Norwegian CAA regarding the conduct of skill-tests and the responsibilities of flight examiners.