Bell 407Med-Trans Corp.

A single-engine emergency medical services (EMS) helicopter was destroyed after impacting trees in a national forest about 0532 eastern daylight time. Night visual meteorological conditions with mist and light fog prevailed in the area of the accident site. The flight crew was contacted about 0452 to determine if they could accept the mission. The pilot performed a weather check and accepted the mission about 0455. He departed about 0502. The helicopter arrived at the accident scene and landed on the interstate highway near a rest stop about 0523. The helicopter departed the scene about 10 minutes later, flying toward the national forest located north of the interstate. A witness reported that the helicopter made no abrupt maneuvers and that the engine "didn't sound like it was missing, sputtering, or any other kind of power loss." He reported that the helicopter was straight and level then it "pitched forward to go forward." He reported the helicopter was "flying level" as it descended into the trees. He reported that the helicopter's searchlight was on and that fog and mist were visible at treetop level. Postaccident inspection of the helicopter revealed no preexisting anomalies that could be associated with a pre-impact condition. Download of the engine's electronic control unit nonvolatile memory indicated that the engine was operating at 98 percent Ng when it impacted the trees. Three other EMS helicopter operators had turned down the mission, including one who had attempted it but had to return because of fog conditions. However, the accident pilot was not informed that other pilots had declined the mission because of fog.