ERA15LA015

About 20 minutes into a visual flight rules cross-country flight, the airplane's engine began running roughly and shortly thereafter began losing power. The pilot initially attempted to divert to an airport about 20 miles away, but as the engine's power output continued to gradually decrease, the pilot instead decided to perform a precautionary landing to a farm field. During the landing, the airplane touched down hard resulting in substantial damage to the airframe. Postaccident examination of the engine revealed that the engine's No. 1 cylinder compression was intermittently low, that the head of the intake valve of that cylinder was deformed, and that the valve was not seating properly. The deformation of the intake valve may have been the result of high valve seating forces that occurred as the result of improperly adjusted valve spring tension. However, the airplane's maintenance records did not note any maintenance actions to the cylinder or its internal components between the last engine overhaul and the accident. While a maintenance log entry documenting the engine overhaul indicated that new cylinder assemblies were installed at that time, it did not indicate when the spring tension for the valve was last set.

On October 12, 2014, about 1350 eastern daylight time, a Piper PA-28-151, N57SH, was substantially damaged during an off-airport landing near Granville, Massachusetts. The private pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the flight, which departed from Floyd Bennett Memorial Airport (GFL), Glens Falls, New York and was destined for Norwood Memorial Airport (OWD), Norwood, Massachusetts. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. According to the pilot, about 20 minutes into the cross-country flight, the engine began running roughly. He scanned the engine instruments and noticed that the tachometer was still showing a normal rpm reading, but that the No. 1 cylinder's digital temperature indication graph was blank. Shortly thereafter, the engine began losing power, and the pilot advised air traffic control that he intended to divert to Westfield-Barnes Regional Airport (BAF), Springfield, Massachusetts, located about 20 miles away. Shortly thereafter, the pilot observed the No. 1 cylinder temperature briefly change from no indication to a full red bar, then back to no indication. As the engine's power output continued to gradually decrease, the pilot decided to perform a precautionary landing to a farm field. Approaching the field, the pilot felt that the airplane was too high and too fast for landing, so he performed a go-around in order to approach the field from the opposite direction. During the second landing attempt, the airplane touched down "hard," collapsing the nose landing gear and resulting in substantial damage to the firewall. A Federal Aviation Administration inspector examined the airframe and engine following the accident. During the examination, the inspector noted that the compression of the engine's No. 1 cylinder was intermittently lower than expected. Disassembly and examination of the cylinder revealed that the intake valve was not seating properly and that the hydraulic lifter spring was rubbing against the inside of the spring containment barrel. Removal of the intake valve revealed that the head of the valve was deformed and the stem was elongated by 0.1 inches when compared to another similar valve. The No. 1 cylinder assembly was forwarded to the NTSB materials laboratory for detailed examination. The examination confirmed that the deformed intake valve displayed the correct part number, that the material was of the proper hardness and alloy. The examination further confirmed the head of the valve displayed "cupping" or "tuliping" deformation. Review of maintenance logs for the airframe and engine revealed that the airplane's most recent annual inspection was completed on July 21, 2014, about 19 flight hours before the accident. An overhaul of the airplane's engine was most recently completed in May 2012, about 121 flight hours before the accident. The maintenance log entry documenting the engineoverhaul contained a parts list that noted the installation of, "New Lycoming nitrided cylinder assy's…" The logs did not note any maintenance to the No. 1 cylinder or its internal components between the time of the engine overhaul and the accident.