Archer Aviation evacuated about 100 people after a battery-test fire at its 77 Rio Battery laboratory in San Jose, California, on Monday. Three people were evaluated and released after a test pack containing fewer than 30 Molicel lithium-ion cells entered thermal runaway. The pack was for a future battery programme, not the company’s Midnight electric vertical-takeoff-and-landing aircraft, limiting the immediate impact on that aircraft’s development.
The incident occurred during routine testing and was attributed to employee error in Archer’s report to California emergency-services authorities. Firefighters moved the affected pack into a suppression tank, where fire-watch personnel monitored it overnight. Republic Services was engaged to dispose of the batteries and manage related cleanup.
Archer indicated that the fire was quickly extinguished, the facility was safely evacuated and the evacuation order was later lifted. Chief executive Adam Goldstein said the company had identified the root cause and resumed testing the following day.
Archer has not disclosed the specific employee error, the nature of the injuries, the pack’s detailed configuration or the future programme associated with the test article. The incident occurred in battery development operations separate from the Midnight programme.