NTSB Factual Report

On January 25, 2008, at 1210 eastern standard time, a Piper PA-28-R200, N1939T, was substantially damaged during a forced landing in York, South Carolina. The certificated private pilot and passenger received minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the flight that originated at Rock Hill Airport (UZA), Rock Hill, South Carolina, and was destined for Asheville Airport (AVL), Asheville, North Carolina. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91.

According to the pilot, he departed UZA, and while climbing through 4,000 feet, the airplane experienced a "sudden and violent shuddering," followed by smoke penetration into the cockpit. The pilot turned toward York Airport (01SC), and prepared for an emergency landing. He pulled the mixture control to the idle cut-off position and turned the master switch to "off." When the pilot realized he would not be able to reach the airport, he located a field adjacent and to the east of the airport, and performed a forced landing. During the landing rollout, the nose wheel dug into the soft ground and the airplane abruptly came to rest.

Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed the wings were substantially damaged. Examination of the Lycoming IO-360 engine revealed the number 2 cylinder had separated from the engine crankcase and the cylinder hold down nuts were broken off of the base studs. The base of the number 2 cylinder, as well as the engine crankcase, displayed fretting as well as a substantial amount of impact damage from the cylinder and connecting rod. No discoloration or heat distress was noted on any of the parts.

The number 2 cylinder, associated through-bolts, and the threaded end of a stud, still held in a nut, were sent to the National Transportation Safety Board Metallurgical Laboratory for further examination. The examination noted fatigue cracking on both of the through-bolts and on the threaded end of the stud still in the nut. The damage to the cylinder, piston, and connecting rod was determined to be secondary to the fatigue cracking in the bolts and studs.

The entire engine was further examined at the Lycoming factory under the supervision of a Safety Board investigator. The examination of the crankcase revealed evidence of welding repairs on the outside of both crankcase halves, and the interior surfaces near the number 2 cylinder. According to Lycoming engineering documents, welding should not be performed inside the critical cylinder deck area. Additionally, the crankcase hardness was measured in two locations on the number 2 cylinder mounting flange. Both locations measured well below the minimum hardness requirements on all Lycoming crankcase engineering drawings.

Examination of the four crankcase through-studs revealed they were yellow in color, compared to the standard silver-gray color of through-studs manufactured by Lycoming. Additionally, the threaded length of the studs was required to be a minimum length of 0.840 inches. The subject studs were measured to be 0.66-0.68 inches in length. One of the unbroken studs was subjected to a tensile test, in which it measured 169.4 ksi (with a maximum load of 21,500 pounds). A sampling of 19 through-studs from 2005-2008 receiving inspection at Lycoming ranged in strength from 172.6-180.9 ksi, with an average of 177.4 ksi.

According to the airplane and engine logbooks, the engine was overhauled and reinstalled on the airplane on January 27, 2006. During the overhaul, the crankcase was sent to another facility for overhaul. The crankcase overhaul facility could not provide records of the work performed.

The airplane's most recent 100-hour inspection was completed on August 22, 2007. At that time, the airplane had a tach time of 3,329 hours, and 586 hours since major overhaul (SMOH). At the time of the accident, the airplane had accumulated 679 hours SMOH.

NTSB Probable Cause

Loss of engine power due to improper welding of the crankcase, which resulted in fatigue failure of the through-studs and a subsequent separation of the number two cylinder. Contributing to the accident was the unsuitable terrain for a forced landing.