Pilot Debrief

CESSNA 210 near Walsh, CO — 2009-10-27

Final reportCEN10LA032
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Date
2009-10-27
Location
Walsh, CO, USA
Aircraft
CESSNA 210
Registration
N7464E
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Cruise

Probable cause

A partial loss of engine power due to failure of the No. 2 cylinder as a result of the failure of the repair facility to properly torque the lower four nuts on the cylinder.

NTSB narrative

The airplane was in level cruise flight at 6,500 feet mean sea level when the pilot "detected a slight smoke smell." Oil pressure and oil temperature readings were normal, but he noticed the EGT (exhaust gas temperature) on one of the cylinders had dropped, followed shortly thereafter by the EGT decay of another cylinder. The pilot was forced to make an emergency landing in an open field. Recent rains had softened the ground and when the nosewheel touched down, the airplane nosed over. An FAA airworthiness inspector who examined the engine said that the cylinder hold-down studs on the lower side of the number 2 cylinder had threads, but one stud had snapped off. Further examination of the engine revealed that the lower four nuts on the number two cylinder were not properly torqued, which allowed the lower side of the cylinder to move while the upper part remained fixed. A crack developed on the right side of the cylinder and propagated along the bottom lip to the left side of the cylinder, eventually reaching the point of failure. When the annual and 100-hour inspections were done on August 21, 2009, all 6 cylinders had been removed “due to low compression” and replaced with overhauled cylinders, new pistons and rings, and new gaskets and seals. Airframe total time was 3,797.79 hours, and the time since major engine overhaul was 1,239.82 hours. The tachometer read 2960.72. At the accident site, the tachometer read 3059.41 hours.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Proper torque of cylinder nuts during maintenance could have prevented failure.

NTSB coding

Evidence available

  • Photos
  • 8 docket documents
View NTSB final reportView NTSB docket

Docket documents8

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