What happened
On May 10, 2008, at approximately 2237 CDT, an Eurocopter Deutschland GmbH EC 135 T2+ helicopter, N135UW, crashed into trees and terrain near La Crosse, Wisconsin. The aircraft, operated by Air Methods Corporation, had departed La Crosse Municipal Airport (LSE) at 2234 for a return flight to the University of Wisconsin Hospital heliport (WS27).
At the time of the accident, the flight was being conducted under night visual meteorological conditions. A witness near the airport reported seeing the helicopter traveling at a high rate of speed and flying low, noting a concern that it might not clear the nearby bluffs. Shortly after, another witness reported hearing the sound of the engine disappear, followed by a loud crash. The wreckage was located the following morning on a descending hillside approximately 4.5 miles southeast of LSE. The crash resulted in 3 fatal injuries, claiming the lives of the pilot, the physician, and the flight nurse.
The investigation
The investigation examined the wreckage and the aircraft's mechanical systems. The helicopter impacted the tops of 50- to 60-foot-tall trees at an elevation of approximately 1,164 feet. The distribution of the wreckage was consistent with a nearly level flight attitude under controlled flight. While the left engine selector switch was found in the idle position, investigators determined this was likely caused by the impact rather than a mechanical failure, as the digital engine control units showed the engines were in flight mode at the time of impact.
Engine inspections revealed debris in the air inlets and evidence of overload failure in the left engine power turbine blades. The aircraft was equipped with a radar altimeter but lacked a terrain awareness and warning system (TAWS).