The UK Air Accidents Investigation Branch (AAIB) has concluded that a manufacturing defect resulting in the release of a propeller blade doomed Vertical Aerospace’s VX4 prototype during a test flight.
According to the investigation, the aircraft, operated by a remote pilot, was flying at an altitude of 30 feet above ground level when a propeller blade detached from the electric propulsion unit 3 forward motor. This detachment occurred due to a failure of the adhesive bond between the propeller blade sheath and spar, attributed to a manufacturing fault. The sudden release of the blade generated significant out-of-balance loads, leading to structural failure of the right inboard pylon and subsequent damage to the aircraft’s wiring harnesses. As a result, thrust was lost from motors 4 and 7.
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Despite the aircraft’s flight control system’s ability to maintain a level attitude, the loss of vertical thrust caused a rapid descent, resulting in substantial damage upon impact with the ground.
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Notably, Vertical Aerospace was in the process of introducing a new blade design aimed at addressing the bonding failure mode identified in the investigation. The manufacturer’s own inquiry highlighted 36 product and process improvements stemming from the incident.
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This incident underscores the critical importance of rigorous quality control and manufacturing standards in the aerospace industry, particularly in the development of cutting-edge electric propulsion systems. As Vertical Aerospace continues its pursuit of innovative air mobility solutions, lessons learned from this event are likely to inform future advancements and safety measures.
SOURCE: UK Air Accidents Investigation Branch (AAIB)