Aviation Accident Summaries

Aviation Accident Summary CHI00LA046

OMAHA, NE, USA

Aircraft #1

N7339X

Cessna 150B

Analysis

The aircraft experienced an engine failure after departure. The certified flight instructor (CFI) executed a forced landing on a road where the aircraft wing contacted a semi-truck. A postaccident examination revealed no preexisting anomalies with respect to the aircraft or aircraft systems. The CFI reported no mechanical malfunction. A weather report stated a temperature of 32 degrees F., and a dewpoint of 28 degrees F. According to the carburetor icing chart by Transport Canada, the temperature and dewpoint at the time of the accident fall within the range of serious icing potential. FAA AC 20-113 states, 'When the relative humidity is above 50 percent and the temperature is below 70 degrees F., apply carburetor heat briefly immediately before takeoff, particularly with float type carburetors, to remove any ice which may have been accumulated during taxi and runup.'

Factual Information

On December 14, 1999, at 0910 central standard time, a Cessna 150B, N7339X, owned and piloted by a certified flight instructor (CFI), sustained substantial damage during a forced landing on a road, following an engine failure during climbout from the North Omaha Airport (3NO), Omaha, Nebraska. Visual meteorological conditions prevailed at the time of the accident. The local instructional flight was conducted under the provisions of 14 CFR Part 91 and was not on a flight plan. The CFI and dual student reported no injuries. The flight was originating at the time of the accident. In a written statement, the CFI stated, "shortly after departure, approximately 700 feet agl, 2,022 feet msl, the aircraft experienced a failed engine." The CFI stated that she executed a forced landing on a road and the aircraft contacted a semi-truck. A postaccident examination of the aircraft by the Federal Aviation Administration (FAA) revealed no preexisting anomalies with respect to the aircraft or aircraft systems. In a written report, the CFI reported no mechanical malfunction. The Eppley Airfield weather reporting station (OMA), Omaha, Nebraska, located 7 miles on a magnetic heading of 124 degrees from the accident site reported, at 0852, clear skies, winds from 090 degrees at 6 knots, an altimeter setting of 29.80 inches of mercury, a temperature of 32 degrees F., and a dewpoint of 28 degrees F. A carburetor icing probability chart developed by Transport Canada depicts regions of temperature and dewpoint that are conducive for the development of carburetor ice. FAA Advisory Circular AC 20-113 "Pilot Precautions and Procedures to be Taken in Preventing Aircraft Reciprocating Engine Induction System and Fuel System Icing Problems" states under Prevention Procedures, "When the relative humidity is above 50 percent and the temperature is below 70 degrees F., apply carburetor heat briefly immediately before takeoff, particularly with float type carburetors, to remove any ice which may have been accumulated during taxi and runup.

Probable Cause and Findings

The pilots failure to use carburetor heat during takeoff in weather conducive for serious carburetor ice. Factors were the weather that was conducive for carburetor icing and the presence of the truck that the aircraft impacted.

 

Source: NTSB Aviation Accident Database

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