NTSB Identification: ERA12LA428
14 CFR Part 91: General Aviation
Accident occurred Sunday, July 01, 2012 in Greene, NY
Probable Cause Approval Date: 02/03/2014
Aircraft: CESSNA R172K, registration: N758JQ
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The pilot reported that about 25 minutes into the flight while the airplane was at an altitude of about 2,300 feet mean sea level, the engine began to run rough, followed by partial loss of power. He turned and proceeded toward an airport then he started hearing metallic grinding sounds as the engine power continued to decrease. Unable to maintain altitude, he elected to land downwind on a runway; he noted that his airspeed was about 100 knots at the threshold. The main landing gear contacted the surface about midpoint of the runway, and the pilot pushed the control yoke to force the nose landing gear onto the runway in an intentional effort to stop the airplane before running off a steep embankment. The airplane came to rest upright about three-quarters of the way down the length of the runway, with structural damage to the engine firewall.

Postaccident examination of the engine revealed the head of the No. 3 cylinder had separated from the barrel due to an undetected fatigue crack that emanated from corrosion pits on the outer surface of the barrel. Paint covering crater-shaped corrosion blisters on the barrel indicates that the paint was applied to a surface that had already corroded and suggests that the corrosion developed over an extended period of time. Although the engine had only accrued about 9 hours since the last 100-hour inspection, the location of the piston at top dead center during the compression test would have been above the location of the fracture and the loss of compression likely would not have been detected.

The engine manufacturer recommended that the engine be overhauled every 1500 hours or every 12 years. Although components of the cylinders were replaced in 1986, there was no record that the No. 3 cylinder had been replaced since the airplane was manufactured in 1979. Notably, the engine had accumulated about 1356 hours since installation and had not reached the manufacturer's recommended hour limit for overhaul. However, the 12-year time limit had been significantly exceeded and an overhaul would have involved either installing new or overhauled cylinders. Operating under 14 Code of Federal Regulations Part 91, the owner was not required to adhere to the manufacturer's overhaul recommendations. However, following both the manufacturer's recommended time and hour limitations would have likely addressed the fatigue cracking prior to the accident.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

An undetected fatigue crack on the outer surface of the No. 3 cylinder barrel that could only have been detected visually and not by a differential compression test , resulting in separation of the head from the barrel and a subsequent partial loss of engine power. Contributing to the accident was the pilot's decision to land downwind on a runway that subsequently necessitated an intentional hard landing to avoid a runway overrun and his failure to follow the engine manufacturer's time between overhaul recommendation .

Full narrative available

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