CEN13LA359

The pilot stated he was on final approach to a private helipad about 80 to 100 feet above the ground at an airspeed of 40 knots when the engine lost partial power. He lowered the collective and touched down short of the helipad on the edge of tall grass and dirt, and the helicopter subsequently bounced. A postaccident examination of the airframe and a test run of the engine in a test cell and on the airframe identified no anomalies that would have precluded normal operation. The cause of the partial loss of engine power could not be determined.

On June 19, 2013, about 1620 central daylight time, N467AE, a Bell BH-206 L-4 helicopter, sustained substantial damage when it made a forced landing after a partial loss of engine power while on final approach to a private helipad (AE02) in Lake City, Arkansas. The commercial pilot, flight nurse, and the paramedic were not injured. The helicopter was registered to a private entity and operated by Air Evac EMS, Incorporated, O'Fallon, Missouri. Visual meteorological conditions prevailed and a company visual flight rules flight plan was filed for the repositioning flight conducted under 14 Code of Federal Regulations Part 91. The flight originated from a private helipad (AE03) in Sikeston, Missouri, about1534. The pilot reported that the helicopter was approximately 80-100 feet above the ground at an airspeed of 40 knots when the engine lost power. He described the power loss as being similar to when a turbine engine rolls back to flight idle. The pilot lowered the collective to conserve rotor rpm, and touched down short of the landing pad on tall grass/dirt and bounced, which resulted in damage to the skids and the tail boom. According to the operator, the helicopter and the engine had accrued a total of 154.3 hours since new. An airframe examination was conducted on June 25, 2013, at the operator's maintenance facility in Pomona, Missouri, under the supervision of the Federal Aviation Administration (FAA). Examination of the helicopter's main rotor, tail rotor, flight control, and hydraulic systems revealed no pre-impact anomalies. In addition, examination of the fuel system revealed no leaks or discrepancies that would have contributed to a loss of engine power. The engine was examined at Rolls Royce in Indianapolis, Indiana, on July 9, 2013, under the supervision of the National Transportation Safety Board (NTSB). The engine was placed on a test-cell stand where it was visually examined and checked for leaks. No leaks or discrepancies were observed that would have precluded the engine from being run. The engine was then placed in an engine test-cell and run in accordance to the Rolls-Royce 250-C30 series overhaul manual. The engine was started and ran through its full power range twice. No anomalies were identified that would have contributed to a loss of engine power. The engine was returned to the operator and re-installed on the helicopter using the same controllers and a ground run was conducted in accordance with the manufacturer's Operational Acceptance Flight Checklist for the BH-206L. The purpose of the test was to try and duplicate the loss of engine power reported by the pilot and to determine if any other anomalies may have contributed to the accident. The ground run did not identify any anomalies with either the airframe or engine that would have contributed to a partial loss of engine power. The pilot held a commercial pilot certificate for rotorcraft-helicopter, and an instrument rating for rotorcraft-helicopter. He reported atotal flight time of 5,380 hours; of which, 2,007 hours were in the same make/model helicopter as the accident helicopter. Weather at Jonesboro Municipal airport (JBR), about 10 miles southwest, at 1553 was reported as calm wind, 10 miles visibility, few clouds at 4,400 feet, temperature 29 degrees C, and a dewpoint 20 degrees C.