LAX83FA287

The plt took off on a demonstration flt to familiarize the passengers with the helicopter. He reported that after takeoff, he proceeded northeast at about 100 to 150 ft AGL & 80 KTS in wind that was from the west at 25 gusting 30 KTS. After traveling about 3 mi, he turned left toward a westerly direction, using aprx a 30 deg bank. He stated that just prior to rolling out of the turn, the helicopter started to rapidly lose alt & the forward & aft cyclic control would not respond to his imputs. Subsequently, the helicopter impacted the ground. He believed that the wind had shift & the helicopter may have turned downwind & began setting with power. According to a passenger, when the helicopter was in the turn to the west, he felt a thump, the acft began climbing, then went into a 360 deg spin to the right. No preimpact/part failure or malfunction was found. The 3 servo actuators were tested & all 3 functioned properly. Local plts reported the winds were often unpredictable due to rolling hills in the area.