A Heli-Flite Sikorsky S-58ET crashed into a Raytheon Space and Airborne Systems missile guidance warehouse Sunday morning in El Segundo, Calif., seriously injuring the pilot and igniting a four-alarm fire that damaged two floors of one of the buildings in the complex that houses infrared radar systems and missile guidance components. The helicopter was removing an air conditioning unit from the building’s roof when witnesses said it appeared to lose directional stability and plunged into a patio area alongside the building. Workers on the scene pulled the injured pilot from the burning helicopter before the conflagration escalated. Firefighters had the fire under control within 40 minutes. The pilot is recovering from injuries sustained in the crash and remains hospitalized. Heli-Flite, dba Aris Helicopters, is based in Riverside, Calif., and offers helicopters for construction/heavy lifting, firefighting and charter work, among other roles. The company is also an FAA-certified repair station for fixed- and rotary-wing aircraft.