NTSB Identification: ANC04LA109.
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Accident occurred Tuesday, September 14, 2004 in North Pole, AK
Probable Cause Approval Date: 02/24/2005
Aircraft: Cessna 140, registration: N1629V
Injuries: 1 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
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.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's failure to use carburetor heat during takeoff/initial climb, which resulted in a total loss of engine power, and an in-flight collision with trees. Full narrative available
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