WPR11LA193

According to the pilot, the airplane was in cruise flight at 5,500 feet mean sea level (msl) when he observed haze ahead, and he decided to descend to 3,500 feet msl. The pilot reported that, at 4,000 feet msl, the engine began to lose power. The pilot stated that he cycled the throttle and then the propeller, but the engine power was not restored. The pilot then turned on the fuel boost pump with no change in power noted. The pilot said that he did not apply carburetor heat. The pilot said that, about 300 to 400 feet above ground level, the engine "finally reached what felt like near idle." During the forced landing, the airplane collided with an embankment. The regional weather conditions at the time of the accident were such that the route of flight was directly into a cold front with increasing moisture and relative humidity. A weather station about 11 nautical miles from the accident site reported a temperature of 32 degrees F and dew point of 30 degrees F at the time of the accident. These weather conditions were conducive to the formation of serious carburetor icing at cruise power. A postaccident examination of the engine found no preaccident mechanical malfunctions or failures that would have precluded normal operation. It is likely the engine began to lose power due to carburetor ice and that the timely application of carburetor heat would have restored engine power.

On April 8, 2011, approximately 1130 Pacific daylight time, a Bartholomew Lancair 320 experimental amateur-built airplane, N320BB, sustained substantial damage during a forced landing following a loss of engine power near Temple Bar Airport (U30), Temple Bar, Arizona. The commercial pilot, the sole occupant, received minor injuries. The owner/pilot was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the personal cross-country flight, which had originated in Las Vegas, Nevada, approximately 20 minutes before the accident. A flight plan had not been filed. According to the pilot, he was in cruise flight at 5,500 feet mean sea level (msl) when he observed haze ahead, and he decided to descend to 3,500 feet msl. At about 4,000 feet msl, he noticed “the engine slowly winding back.” The pilot stated that he cycled the throttle and then the propeller, but engine power was not restored. The pilot then turned on the fuel boost pump with no change in power noted. The pilot reported that he did not apply carburetor heat. Approximately 300 to 400 feet above ground level (agl), the engine "finally reached what felt like near idle." During the forced landing, the airplane collided with an embankment and the landing gear collapsed, the right wing and the bottom of the fuselage were damaged, and the rudder separated from the vertical stabilizer. The regional weather at the time of the accident included a low pressure over southern Utah with a cold front extending on a north-south line across Arizona into Mexico. The front was immediately east of the accident site and perpendicular to the pilot’s route of flight. Departure weather at North Las Vegas Airport, at 1053, was: wind 170 degrees at 15 knots, gusting to 25 knots; visibility 10 miles; clear of clouds; temperature 52 degrees Fahrenheit (F); dew point 18 degrees F. As the flight proceeded eastward, weather observations and satellite imagery indicate that cloud cover increased and became lower, with increasing moisture and relative humidity. At 1124, the weather at Kingman, Arizona, located 160 degrees for 50 nautical miles (nm) from the accident site, was: wind 240 degrees at 14 knots; visibility 6 miles; clouds starting at 900 feet agl, with overcast conditions at 1,600 feet agl; temperature 37 degrees Fahrenheit; dew point 36 degrees Fahrenheit. Kingman was also reporting light rain and mist, with deteriorating conditions by 1205 of light snow and overcast cloud conditions at 900 feet agl. A Remote Automated Weather Station (RAWS), a Federal interagency weather station, was located approximately 010 degrees for 11 nm from the accident site. At the time of the accident, the RAWS reported a temperature of 32 degrees F and dew point of 30 degrees F. According to a carburetor icing chart, this temperature and dew point place the airplane in serious carburetor icing conditions at cruise power. Postaccident examination of theengine was performed by a Federal Aviation Administration inspector and no deficiencies were noted that would have precluded normal engine operation. A detailed report of this examination can be found in the public docket for this investigation.