The U.S. National Transportation Safety Board has confirmed component failure resulting in the separation of a propeller as the probable cause of the February 16, 2022, accident in which one of Joby Aviation’s eVTOL prototypes crashed during testing in a rural area of California. The agency’s final report published on February 7 determined that the blade separation caused, “cascading effects to include the separation of multiple propulsion motor/propeller assemblies and the loss of remote pilot control of the aircraft.”
Investigators also identified a flaw in the tilt-rotor actuator link in part of the propulsion system that allowed propeller blades to be at a steeper angle than commanded to be a contributing factor. There were no injuries resulting from the crash, which occurred when the aircraft was flying at an altitude of 8,900 feet, having reached its maximum dive speed of 181 knots indicated airspeed, which was slightly its top speed.
Information in the NTSB’s accident docket shows that the propeller blade release was from the aircraft’s “propulsion station 3” located on the right wing inboard. The report did not include any safety recommendations.
In a statement, Joby said that since the accident it has incorporated a range of improvements to the design of the four-passenger piloted aircraft it aims to bring into commercial service in 2025. It said that the second prototype aircraft has made over 100 flights, including with a pilot on board, and has logged almost 25,000 hours.
“We continue to work with the FAA to ensure that the type certification process reflects our learnings and we are committed to sharing relevant learnings with other eVTOL companies to further support the safety of our entire industry,” the California-based company said.
In August 2023, a prototype of Vertical Aerospace's VX4 eVTOL aircraft crashed during a flight test in the UK. The company said that its initial report to the UK's Air Accident Investigation Branch concluded that faulty bonding had caused one of the propellers to break away from the propulsion system causing the remotely piloted aircraft to crash.