Public demonstration flights of Lift Aircraft's Hexa eVTOL vehicle at the Osaka-Kansai World Expo in Japan have been temporarily suspended following an April 26 incident in which the single-seat model suffered an apparent mechanical failure.
The piloted multicopter was flying at an altitude of 10 meters on approach to the Expo Vertiport at approximately 3 p.m. local time when one of its 18 propellers broke, damaging the structure that connects it to the aircraft’s fuselage, according to the Flight Safety Foundation’s Aviation Safety Network.
After a loud cracking sound, two plastic motor covers fell to the ground, according to the ASN report, which included a video of the incident. Nobody was injured, and no ground damages were reported. The Hexa safely landed back at the Expo Vertiport as planned, with the broken propeller still dangling from its backside.
Acknowledging the incident, Austin, Texas-based Lift said that safety remains its highest priority. "Hexa was designed to be incredibly fault tolerant with multiple redundant systems specifically to address component failures, and we're pleased that these systems performed exactly as intended," the company's chief of staff, Kristin Giffin told AIN. "During the recent demonstration flight, our aircraft experienced failure of one of its 18 powertrain units. The failure was contained, resulting in the loss of power to one motor, and the aircraft continued to fly in a fully controlled manner as designed. Our chief pilot returned the aircraft to the designated landing area and performed a normal landing."
Despite the broken propeller, the aircraft appeared to remain stable during the approach and landing, which would seem to be a testament to the safety and efficacy of its redundant flight control and propulsion systems. Japan's Civil Aviation Bureau has determined that the event did not merit an investigation led by the agency as the component failure did not result in significant damage to the aircraft and was not deemed to constitute a significant safety risk.
Other Flight Demos at World Expo
The Hexa is one of several eVTOL aircraft slated to participate in public flight demonstrations at the six-month-long World Expo event, which opened to the public on April 13. In partnership with local operator Marubeni Corporation, Lift performed its first World Expo demo flight on April 14. Japan’s SkyDrive opened the event with the debut of its three-seat SD-05 eVTOL air taxi.
Lift started the flight demonstrations in Osaka on April 14 as a prelude to launching further flight operations in the city this summer, with the intention of giving prospective customers for the personal eVTOL vehicle the chance to train to fly the Hexa. The company has not yet commented on the incident and how it might impact these plans.
Marubeni is also a prospective operator for the four-passenger VX4 eVTOL aircraft being developed by the UK's Vertical Aerospace. In 2021, it signed what was described as a "pre-order option" for 200 examples of the aircraft, which is now expected to enter service in 2028.
Vertical has indicated that it plans to demonstrate a VX4 prototype during the World Expo in October. U.S. companies Joby Aviation and Archer Aviation also intend to demonstrate their respective four-passenger eVTOL aircraft at the event, but those flights have not yet been scheduled.
Lift said it expects to resume demonstration flights in Osaka, with its engineering team now in the process of implementing measures to prevent a similar incident based on their own investigation into the root cause. World Expo attendees will have the opportunity to experience the flights virtually in full-motion VR flight simulators that Lift is showcasing at the event.
The company designed the Hexa single-seat electric multicopter to operate under the FAA's Part 103 rules for powered ultralight aircraft, which do not require type certificates. It is also developing an autonomous cargo-carrying variant for the U.S. Army.
This story was updated on April 30 to include additional information and comments from Lift Aircraft.