/*Federal Aviation Administration*/ spokesman Ian Gregor said the Piper Cherokee went down near Cherry Valley, southeast of Yucaipa.
The aircraft burst into flames after crashing.
Investigators believe the pilot was the only person on board.
The /*FAA*/ and the /*National Transportation Safety Board*/ will investigate the cause of the crash.
The pilot's name and the plane's tail number were not immediately released.
The Associated Press contributed to this report.
