The UK Air Accidents Investigation Branch (AAIB) has published its report into the forced landing of Vertical Aerospace’s eVTOL (electric vertical takeoff and landing craft), the VA-1X, which suffered a power unit failure at Gloucestershire’s Cotswold Airport in August 2023.
The incident happened during a remotely piloted flight test designed to assess the effect of one engine inoperative performance during an out-of-ground-effect-hover. However, at approximately 30 feet above the ground, a propellor blade became detached from an electric propulsion forward motor; causing structural failure of the right inboard pylon. Although the aircraft’s flight control system was able to maintain a level attitude, the loss of vertical thrust caused a high rate of descent. The prototype aircraft subsequently suffered substantial damage upon impact with the ground at approximately twice the limit descent velocity that it was designed to withstand.
Post-incident analysis indicated that the rotor blade release was caused by “a failure of the adhesive bond between the propeller blade and spar,” with manufacturing defects likely to have grown larger during the blade’s operational service. Vertical Aerospace subsequently “identified the propeller blade’s structural design, the manufacturing controls, quality assurance processes and verification programme as contributory factors to the blade failure” notes the AAIB, which adds that the manufacturer “was, at the time of the accident, in the process of introducing a revised propeller blade design”.
Vertical Aerospace has identified 36 product and process improvements resulting from findings of the investigation. The company concludes that it is no longer using the same blade supplier and, through its close work with the AAIB, “strongly believes transparency and openness are fundamental to the safety of aerospace”.
Subscribe to the FINN weekly newsletter
