Pilot Debrief

CESSNA 172 near Manassas, VA — 2024-04-15

Final reportERA24LA178
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Date
2024-04-15
Location
Manassas, VA, USA
Airport
HEF
Aircraft
CESSNA 172
Registration
N8337X
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Descent

Probable cause

The pilot’s failure to apply carburetor heat before reducing engine power during a prolonged descent while operating in environmental conditions conducive to the development of carburetor ice, which resulted in a total loss of engine power due to carburetor icing.

NTSB narrative

The pilot reported that the airplane was in cruise flight at 5,500 ft mean sea level (msl) before he reduced engine power to comply with air traffic control descent instructions. The pilot did not apply carburetor heat at any time during the descent from 5,500 ft to 2,000 ft. At 2,000 ft msl, with the destination airport in sight, he applied throttle, but the engine did not respond. The pilot informed the tower controller that the “motor was unresponsive” and was cleared to land. The airplane touched down in a grassy area on airport property short of the runway, collided with a drainage culvert, and nosed over, resulting in substantial damage to the vertical stabilizer and the right-wing lift strut. Although low compression was noted in two cylinders during the postaccident engine examination, that condition was attributed to leakage past the intake valves and likely would not have resulted in the total loss of engine power reported by the pilot. Review of weather information indicated that the airplane was operating in an area conducive to the development of serious carburetor ice at glide or idle engine power settings. It is likely that the carburetor accumulated ice during the prolonged descent without the use of carburetor heat, which resulted in the total loss of engine power.

Analysis

Primary failure mode
Fuel management
First missed decision gate
Pilot did not apply carburetor heat during descent despite icing conditions.

NTSB coding

Evidence available

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

Docket documents10

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