WPR09LA314

The certified flight instructor (CFI) and student pilot were on a local instructional flight. The CFI stated that during cruise flight, the rpm dropped suddenly and he lowered the collective while rolling on the throttle. The engine did not respond and the helicopter impacted the ground. The CFI indicated that carburetor heat had been applied shortly before the power loss occurred. Post accident test run of the engine did not reveal any operational anomalies. At the time of the accident, the Federal Aviation Administration icing probability chart showed that icing conditions existed at glide and cruise power.

On June 25, 2009, at 1815 Pacific daylight time, a Robinson R22 Beta, N836SH, lost engine power during flight and landed hard near Lewiston, Idaho. Lewis and Clark Aviation LLC was operating the helicopter under the provisions of 14 Code of Federal Regulations Part 91. The certified flight instructor (CFI) and student pilot were not injured. Visual meteorological conditions prevailed and no flight plan was filed for the instructional flight. According to the CFI, he and the student were in cruise flight for the student’s first instructional flight. During the flight, the rotor rpm dropped suddenly, and the CFI lowered the collective. Then, he rolled on the throttle but did not get a response. The rpm continued to decrease, and the oil light was illuminated as the helicopter impacted the ground. He attempted to do a run on landing but the skids dug into the ground and the helicopter came to rest on its side with the tail boom separated. In a phone conversation following the accident, the CFI reported that he had applied full carburetor heat about “a couple of minutes” prior to the loss of power. At the accident site, the carburetor control was found approximately 1 inch out from its stop. It is unknown whether the position of the control had moved during the accident sequence. The Federal Aviation Administration (FAA) accident coordinator examined the helicopter at the accident site and following its recovery. The linkage for the carburetor heat was continuous and functional. The engine was test run on the accident helicopter. No mechanical anomalies were observed during the examinations. At 1756, the nearest aviation weather reporting facility reported the dew point as 5 degrees Celsius and the temperature as 25 degrees C. According to the FAA’s icing probability chart, icing conditions existed at glide and cruise power at the time of the accident.