Vertical Aerospace has given an update on its VX4 eVTOL which crashed during testing last month.

The advance aerial mobility developer said that a full-scale prototype of the VX4 aircraft was involved in an “incident” at their flight test centre.

The company said in the “spirit of long-term safety and openness” it wanted to share an update on the incident and flight test programme.

VX4 flight test campaign

Vertical Aerospace wrote: “Vertical concluded its remote thrustborne flight test campaign in July 2023, as the first full-scale VX4 prototype reached its target speed of 40kts (70 kmph), demonstrating exceptional overall stability and control.

“Performance targets were generally exceeded by 10-30% during hover and low speed flights. The prototype performed especially well in sustained hover, typically the most challenging regime for a VTOL aircraft, where it maintained level flight for longer than anticipated.

“The aim of these thrustborne flight tests was to verify acceptable stability, battery efficiency and control characteristics, aerodynamics, structural loads, performance and vibration throughout this speed range – all of which were achieved.”

VX4 incident update

Commenting specifically on the incident, the company said: “Vertical continued further uncrewed flight tests following the completion of the remote thrustborne flight test campaign. The purpose of these was to understand how the aircraft performed outside of its expected operating conditions before the aircraft’s planned retirement.

“During one of these test flights, an unexpected fault occurred causing the aircraft to enter a stable descent, before being damaged on impact with the ground. Vertical completed a swift and thorough investigation and submitted a report to the Air Accidents Investigation Branch (AAIB). Vertical’s investigation identified the root cause to be a fault with a propeller.

“This early generation propeller had already been redesigned prior to the incident, with the issue fully resolved ahead of the next phase of testing. Further recommendations by the investigation are being implemented by Vertical.

“Vertical believes transparency and openness is fundamental to the safety of aerospace. It therefore intends to provide a further full update to the industry on the incident once the AAIB’s investigation has concluded.”
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