ANC04LA109

The private pilot reported that during initial climb from a private airstrip, the engine started running rough, losing power, and then quit. He said he checked the throttle and the fuel selector when the engine started to run rough, but did not apply carburetor heat because he knew he would lose engine rpm with the carburetor heat on. When the engine lost all power, he did not have enough altitude to turn back to the runway, or reach a suitable landing site, and he elected to fly the airplane straight ahead, into trees. The pilot said there were no known mechanical anomalies with the airplane prior to the flight. The nearest official weather reporting station was about 15 miles northwest of the accident site. The METAR at 1755 reported 4 miles visibility in light rain, temperature and dew point were both 36 degrees F, and the ceiling was 400 feet broken, 1000 feet overcast. At the accident site, the pilot estimated a 600 foot ceiling, 3 miles visibility, and both temperature and dew point at 36 degrees F. A carburetor icing probability chart is included in the docket of this report. It depicts the potential for carburetor icing at various temperature and dew point combinations. Using the temperature and dew point of 36 F and 36 F, respectively, the chart indicates there is a potential for serious carburetor icing at cruise and climb power settings. FAA Advisory circular 61-23C, Chapter 2, Carburetor Icing, states, in part: "...if the temperature is between -7C (20F) and 21C (70F), with visible moisture or high humidity, the pilot should be constantly on the alert for carburetor ice. During low or closed throttle setting, an engine is particularly susceptible to carburetor icing." The engine was recovered to a maintenance facility, and placed on an engine test stand. The engine and propeller did not require any repair as a result of the accident. The engine was started and run through various power settings. No mechanical anomalies were found.

On September 14, 2004, about 1820 Alaska daylight time, a Cessna 140 airplane, N1629V, sustained substantial damage following a loss of engine power during initial climb after takeoff, which resulted in the airplane descending into trees, about 3 miles east-southeast of North Pole, Alaska. The airplane was being operated by the pilot as a visual flight rules (VFR) personal local flight under Title 14, CFR Part 91, at the time of the accident. The solo private pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on September 14, the pilot said during initial climb from an unnamed private airstrip east-southeast of North Pole, the engine started running rough, losing power, and then quit. He said he checked the throttle and the fuel selector when the engine started to run rough, but did not apply carburetor heat because he knew he would lose engine rpm with the carburetor heat on. He stated that when the engine quit, he did not have enough altitude to turn back to the runway, or reach a suitable landing site. He said he elected to fly the airplane straight ahead, and descend into the trees. The pilot said there were no known mechanical anomalies with the airplane prior to the flight. He noted that the airplane's fuel tanks had been cleaned this summer, and that he maintained a clean fuel supply, and did not suspect fuel contamination. The pilot said there were low clouds and drizzle at the airstrip during takeoff.

The nearest official weather reporting station was Fairbanks International Airport, Fairbanks, Alaska, about 15 miles northwest of the accident site. The Fairbanks METAR at 1755 reported 4 miles visibility in light rain, temperature and dew point were both 36 degrees F, winds were 160 degrees at 4 knots, and the ceiling was 400 feet broken, 1000 feet overcast. The pilot estimated a 600 foot ceiling, 3 miles visibility, and both temperature and dew point at 36 degrees F.

A carburetor icing probability chart is included in the docket of this report. It depicts the potential for carburetor icing at various temperature and dew point combinations. Using the temperature and dew point of 36 F and 36 F, respectively, the chart indicates there is a potential for serious carburetor icing at cruise and climb power settings. FAA Advisory circular 61-23C, Chapter 2, Carburetor Icing, states, in part: "...if the temperature is between -7C (20F) and 21C (70F), with visible moisture or high humidity, the pilot should be constantly on the alert for carburetor ice. During low or closed throttle setting, an engine is particularly susceptible to carburetor icing."

The airplane's engine was recovered to a maintenance facility in Fairbanks, and placed on an engine test stand. The engine and propeller did not require any repair as a result of the accident. On November 12, in the presence of an FAA aviation safety inspector, the engine was started and run through various power settings. No mechanical anomalies were found.