A jet smashed into a hanger at Chino Airport on Thursday evening while mechanics were conducting an engine run-up test, a Federal Aviation Administration spokesman said.
There were no immediate reports of injuries.
The Challenger aircraft was chocked up on a ramp area and jumped the chocks, Ian Gregor, an FAA spokesman in Los Angeles told The Times.
There were three mechanics on the plane, he said. The plane was not intended for flight, said Gregor, citing preliminary information gathered by the agency.
The fixed-wing multi-engine aircraft is registered to Grady International Inc. in Irvine, according to online FAA records.