Vertical Aerospace has yet to comment publicly on the accident at Cotswold Airport on Wednesday when its VX4 prototype aircraft crashed and seems to have been seriously damaged. As the only flying VX4, the incident will likely have a significant impact on Vertical’s planning.
The eVTOL maker only confirmed to FlightGlobal that the aircraft had an incident during an unmanned flight test, in which a failure of the electromotors was simulated. Under circumstances that need to be investigated, the vehicle lost stability and plunged to the ground. From pictures on social media, it’s difficult to determine the extent of the damage. The fixed wing seem to have partially broken off outside of the two inner electromotors.
The motor failure simulation is an important part of the flight test program. Vertical had moved from tethered to untethered flights at Cotswold Airport in June. It said last week in its Q2 shareholder letter that three untethered and unpiloted flights had been successfully completed. The aircraft demonstrated stable flight in hover and a forty percent transition of the electromotors from their vertical to horizontal position. It isn’t known in what position the motors were in today’s flight test that ended in tatters.
Vertical had planned to progress the thrustborne flight regime to piloted tests later this year using the first prototype. This seems now impossible, as the vehicle is damaged and the cause of the incident needs to be fully understood before flight tests with another VX4 can resume. The second prototype was set for completion before the end of the year and will include various updates and upgrades, including better performance in hover.
Single failure of Propulsion shall not cause HAZ or CAT, ref EASA SC – 19 EHPS. Dual failure of Propulsion shall be controllable. If one EMP fail cause another EMP fail, that is a cascade failure. A cascade failure shall be considered as a single failure. So, how come a motor failure cause crash?
The cause of the incident with the VX4 has not been officially determined yet and is under investigation. We noted in our story only that the incident reportedly happened during a simulated test of a motor failure.