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.
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.
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.
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)