Pilot Debrief

CESSNA 172N near San Rafael, CA — 2023-07-09

Final reportWPR23FA258
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Date
2023-07-09
Location
San Rafael, CA, USA
Airport
CA35
Aircraft
CESSNA 172N
Registration
N4922G
Category
Airplane
Highest injury
Fatal
Fatalities
1
Phase of flight
Descent

Probable cause

The total loss of engine power due to carburetor icing as a result of the pilot’s failure to activate the carburetor heat in a timely manner during the descent.

Contributing factors

Environmental issues Conducive to carburetor icing - Contributed to outcome Personnel issues Delayed action - Pilot

NTSB narrative

The pilot was on a night cross-country flight and began an enroute descent about 65 miles from the destination airport. When the pilot attempted to add engine power to level off at a lower altitude, the engine did not respond. The pilot attempted to troubleshoot the loss of engine power, including selecting carburetor heat, but without success. As the airplane continued to descend, it struck a powerline near the approach end of the runway and impacted a water canal. During the accident sequence the fuselage and both wings sustained substantial damage. The pilot did not report that he activated the carburetor heat during the descent, as called for in the pilot’s operating handbook normal descent procedures “as required – for carburetor icing conditions.” The pilot reported that he would not normally select the carburetor heat until the airplane was below 1500 ft and entering the traffic pattern. Postaccident examination of the airplane revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation. Review of weather information indicated that the airplane was operating in an area conducive to the development of serious carburetor icing at cruise power. It is likely that the carburetor accumulated ice during the prolonged descent without the use of carburetor heat, which resulted in a total loss of engine power. The accident is consistent with a total loss of engine power due to carburetor icing as a result of the pilot’s failure to activate the carburetor heat in a timely manner during the descent.

Analysis

Primary failure mode
Fuel management
First missed decision gate
Pilot did not apply carburetor heat until below 1500 ft, contributing to icing.

NTSB coding

Evidence available

  • ADS-B / radar
  • Photos
  • 11 docket documents
View NTSB final reportView NTSB docket

Docket documents11

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