N6905GCessna 150L · 1970

On December 28, 2013, about 1215 central standard time, a Cessna 150L airplane, N6905G, impacted terrain following a loss of engine power near Gladewater, Texas. The commercial rated pilot and passenger were not injured and the airplane was substantially damaged. The airplane was registered to and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan.

The pilot reported that he departed for a practice flight which included slow flight, stalls, and steep turns. As he returned to the airport, the engine rpm started to decrease. He reported that he performed the restart checklist, but was unable to restore power. The pilot added that he was too low to make it to the airport, and selected a clearing for the forced landing.

A Federal Aviation Administration inspector reported that the airplane impacted trees and terrain, near a pipeline right-of-way. The impact resulted in substantial damage to the airplane's left and right wings. A visual inspection of the engine did not reveal a reason for the loss of power. Additionally, a fuel smell was present on site and an estimated 20 gallons of fuel was available in the airplane's fuel tanks.

The airplane was retrieved by the owner, who examined the airplane's engine. The owner reported that all the connections; fuel line, throttle, mixture, and carburetor heat all were in place. The air filter was free from obstructions, the gascolator and screen were clear of any debris or contaminates. The owner was able to start and run the engine; the owner also added that the airplane ran on automobile gas (mogas).

The carburetor icing probability chart included in Federal Aviation Administration Special Airworthiness Information Bulletin No. CE-09-35, Carburetor Icing Prevention, indicated that the airplane was operating in an area that was associated with a serious risk of carburetor ice accumulation at glide power settings.

In December 2013, the NTSB issued Safety Alert (SA-029) "Engine power loss due to Carburetor Icing". The Safety Alert states that "engines that run on automobile gas may be more susceptible to carburetor icing than engines that run on Avgas".