Pilot Debrief

CESSNA 150M near El Dorado, KS — 2012-01-13

Final reportCEN12LA135
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Date
2012-01-13
Location
El Dorado, KS, USA
Aircraft
CESSNA 150M
Registration
N714BS
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

The loss of engine power for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation.

NTSB narrative

The pilot was on a local flight and the airplane had climbed to an altitude of about 10,700 feet. The pilot reduced the power and established a glide. At an altitude of about 8,000 feet, he advanced the throttle, but the engine only reached about 1,500 rpm. He checked the throttle and mixture controls and applied carburetor heat; however, the engine rpm kept getting lower. During the forced landing in a field, the airplane impacted an embankment and nosed over, coming to rest inverted. An examination of the engine failed to identify any anomalies that would account for a loss of power. A review of the carburetor icing probability chart revealed that the weather conditions were just outside favorable conditions for the formation of carburetor icing. Additionally, the air temperature and moisture content at 8,000- to 12,000-feet altitude were not conducive to carburetor icing. A review of Transport Canada’s publication, TP10737, “The use of automobile gasoline (Mogas) in Aviation,” dated March 31, 1993, noted that, “Mogas is generally higher in volatility than Avgas [aviation gas]. Mogas will thus absorb more heat from the mixing air when vaporizing, resulting in ice accumulation at higher ambient temperatures. The likelihood of carburetor icing while flying on Mogas is higher.” Despite the low power setting during the glide and the use of Mogas, the weather conditions near the accident site did not appear to be favorable for the formation of carburetor icing. The reason for the loss of engine power could not be determined.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot did not apply carburetor heat when engine RPM was low.

NTSB coding

Evidence available

  • 6 docket documents
View NTSB final reportView NTSB docket

Docket documents6

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