CEN16LA349

The private pilot and passenger departed on a night cross-country flight using flight following. About 2 hours after departure, the engine suddenly lost partial power. The pilot checked the engine gauges, which were all in the green, and advised air traffic control (ATC) of the loss of engine power. The pilot switched fuel tanks, then activated the carburetor heat. He tried switching magnetos and enriching the mixture for "a few seconds." He then leaned the mixture again and "deactivated the carb heat," all with no changes observed in engine power. The pilot declared an emergency with ATC and used his tablet computer's navigation application to align the airplane over a road. Upon touchdown, the airplane's wing impacted a guardrail, and the airplane subsequently nosed over. Although weather conditions at the nearest weather reporting facility about 50 miles from the accident site were conducive to the accumulation of serious carburetor icing at cruise power, the investigation could not determine whether the loss of power was a result of carburetor ice, and no postaccident examination of the engine was conducted to rule out other causes.

On September 4, 2016, about 0435 mountain daylight time, a Piper PA 28-180 airplane, N9241J, impacted ground obstacles and nosed over during a forced landing following a partial loss of engine power near Cuba, New Mexico. The pilot and his passenger reported no injuries. The airplane was substantially damaged during the nose over. The airplane was registered to an individual and was operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Night visual meteorological conditions prevailed along the route of flight and the flight did not operate on a flight plan. The flight originated from the Levelland Municipal Airport (LLN), near Levelland, Texas, about 0235 central daylight time, and was destined for the Four Corners Regional Airport (FMN), near Farmington, New Mexico.The flight landed at LLN to obtain fuel and subsequently departed for FMN. About an hour after departing LLN, Albuquerque Center advised the pilot that there was light to moderate precipitation extending approximately 20 miles north of Albuquerque. He observed on an iPad application that the weather was a "non-factor" by the time he reached Albuquerque. The pilot continued the flight northwest and felt the engine suddenly lose power. He checked the engine gauges, which were all in the green. He advised Albuquerque Center of the loss of engine power. The pilot switched fuel tanks then activated the carb heat. He tried switching magnetos and enriching the mixture for "a few seconds." He leaned the mixture again and "deactivated the carb heat." He advised Albuquerque Center that the airplane was not going to be able to maintain altitude and declared an emergency. He used the iPad application map and he aligned the airplane over a road. The airplane's wing impacted a guard rail during the forced landing and the airplane subsequently nosed over. The pilot reported that fuel leaked from the fuel tank caps vents while he and his passenger exited the inverted airplane. At 0453, the recorded weather at the Santa Fe Municipal Airport (SAF), near Santa Fe, New Mexico, was: Wind calm; visibility 10 statute miles; sky condition clear; temperature 16 degrees C; dew point 12 degrees C; altimeter 30.08 inches of mercury. SAF's temperature and dew point were plotted on a carburetor icing probability chart. The plot shows a probability of serious icing at a cruise power settings at the temperature and dew point reported about the time of the accident. The Pilot's Handbook of Aeronautical Knowledge, in part, stated: When conditions are conducive to carburetor icing during flight, periodic checks should be made to detect its presence. If detected, full carburetor heat should be applied immediately, and it should be left in the ON position until you are certain that all the ice has been removed. If ice is present, applying partial heat or leaving heat on for an insufficient time might aggravate the situation. In extreme cases of carburetor icing, evenafter the ice has been removed, full carburetor heat should be used to prevent further ice formation. A carburetor temperature gauge, if installed, is very useful in determining when to use carburetor heat.