A Robinson R-44 helicopter exploded while in motion at Corona Airport leading to the death of the helicopter pilot.  Based on information garnered by local TV stations the Helicopter exploded as it was refueling at the Riverside County Airport. According to Corona Airport authorities and Federal Investigators from the National Transportation Safety Board (NTSB) the cause of the explosion has yet to be determined. There can be different causes of helicopter and aviation accidents including, pilot error, malfunctioning of the aircraft due to a defective part, or failure in proper maintenance of aircraft. The Robinson R-44 is a four seat light helicopter introduced into the market by the Robinson Helicopter Company in 1992.