Pilot Debrief

CESSNA 172N near Rochester, MA — 2009-07-12

Final reportERA09LA399
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Date
2009-07-12
Location
Rochester, MA, USA
Aircraft
CESSNA 172N
Registration
N4773G
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

An engine vibration as reported by the pilot, for undetermined reasons.

NTSB narrative

The pilot reported that the airplane was in cruise flight when the engine developed sporadic engine vibrations. Manipulation of the carburetor heat and mixture controls did not remedy the situation and the engine subsequently developed a severe vibration. The pilot then elected to reduce engine power and perform a precautionary landing to a field. The airplane touched down in a cranberry bog, and sustained substantial firewall and airframe damage. Examination of the wreckage did not reveal any mechanical malfunctions. It was noted that the No. 2 cylinder lower spark plug was fouled and that the compression on the No. 4 cylinder was lower than that of cylinders 1, 2 and 3; however, the reason for the severe engine vibration could not be determined. The airplane had been operated for approximately 74 hours since its most recent 100 hour inspection, which was performed about two months prior to the accident.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have opted for an earlier landing instead of continuing to cruise.

NTSB coding

Evidence available

  • 3 docket documents
View NTSB final reportView NTSB docket

Docket documents3

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