20020702013979A

(.19) On July 02, 2002, at 1445 pacific daylight time, a Robinson R22 beta helicopter, N4072T, was substantially damaged following a loss of control during a precautionary landing near Chatsworth, California. The private pilot sustained minor injuries and his passenger was seriously injured. The helicopter was owned by the dragonfly corporation of dover, Delaware, and was being operated by group 3 aviation of van nuys, California. Visual meteorological conditions prevailed for the 14 code of federal regulations part 91 personal flight for which no flight plan was filed. The local flight originated from the van nuys airport at 1420. The pilot, who had accumulated over 380 flight hours in the R22 helicopter, reported that the helicopter developed a very abnormal vibration while en-route to a local practice area. The pilot added that he became concerned about the unusual vibration and elected to land the helicopter as soon as possible to investigate the source of the vibration. The pilot executed a power-on approach to a terraced paved area located to the right of his intended course. While on the approach on a northerly heading, as the pilot was flaring the helicopter for a landing, control was lost after the main rotor blades came in contact with the terraced terrain to his right-front. The pilot stated that the engine was performing "normally" and he did not experienced a loss of engine power. He added that at the time of the accident, the winds at the accident site were from the south at an estimated 10 to 13 knots. The pilot stated that the engine was performing "normally" and he did not experienced a loss of engine power. He added that at the time of the accident, the winds at the accident site were from the south at an estimated 10 to 13 knots. The helicopter came to rest on its left side. The pilot, who was occupying the right seat, exited the helicopter unassisted, and he then assisted the injured passenger in exiting the helicopter. There was no fire. There were no reported eye-witnesses to the accident. The pilot summoned for help with his cellular phone. (-23) the pilot elected to make a precautionary off field landing due to what he perceived an unusual vibration. The pilot executed a power-on approach to a terraced paved area located to the right of his intended course. While on the approach on a northerly heading, and the pilot was flaring the helicopter for a landing, control was lost after the main rotor blades came in contact with the terraced terrain to his right front. The pilot stated that the engine was performing normally and he did not experience a loss of power. He stated that at the time of the accident, the winds at the accident site were from the south at an estimated 10 to 13 knots. The pilot stated the helicopter rolled over twice and came to rest on its left side. The pilot exited the craft unassisted, then assisted the injured passenger in exiting the helicopter.