A Sikorsky helicopter burst into flames after it crashed into a building in El Segundo Sunday morning, the Federal Aviation Administration said. The accident happened around 9:40 a.m. at the Raytheon plant located at 2000 E. El Segundo Boulevard. The helicopter was lifting a large air-conditioning unit off one of the buildings at the office complex, when the pilot lost control and crashed, authorities said. The helicopter landed in a patio area and burst into flames, setting the first two floors of the building on fire.