The Sikorsky aircraft went down about 9:40 a.m. on Sunday while lifting an air-conditioning unit off the roof of a building at the Raytheon plant located at 2000 E. El Segundo Blvd.
Fire officials said the helicopter plunged into a patio area, setting fire to the building's first and second floors. Fire crews knocked down the blaze in about 40 minutes. No one on the ground was injured.
"It appears that the helicopter caught fire immediately upon contact with the ground," said El Segundo Fire Chief Kevin Smith.
Federal Aviation Spokesman Mike Fergus says the pilot was pulled from the cockpit just before the aircraft burst into flames. The pilot was taken to a hospital with broken bones and cuts.
Officials said the pilot is a man in his 50s and is experienced. His injuries are not life threatening, they said.
Fergus says the Sikorsky was completely destroyed.
The Associated Press contributed to this report.