Accident Overview
On January 25, 2008, at 1210 eastern standard time, a Piper PA-28-R200, registration N1939T, was substantially damaged during a forced landing in York, South Carolina. The certificated private pilot and passenger sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed. The personal flight originated from Rock Hill Airport (UZA) in Rock Hill, South Carolina, and was destined for Asheville Airport (AVL) in Asheville, North Carolina, operating under 14 CFR Part 91.
According to the pilot, while climbing through 4,000 feet, the airplane experienced a "sudden and violent shuddering," followed by smoke penetrating the cockpit. The pilot turned toward York Airport (01SC) and prepared for an emergency landing. He pulled the mixture control to idle cut-off and switched the master to off. Realizing he could not reach the airport, he located a field adjacent and east of the airport and executed a forced landing. During the landing rollout, the nose wheel dug into soft ground, and the airplane abruptly came to rest.
Inspection Findings
Examination by a Federal Aviation Administration (FAA) inspector revealed substantial damage to the wings. The Lycoming IO-360 engine showed that the number 2 cylinder had separated from the crankcase, with cylinder hold-down nuts broken off from the base studs. The base of the number 2 cylinder and the crankcase exhibited fretting and significant impact damage from the cylinder and connecting rod. No discoloration or heat distress was noted on any parts.
Metallurgical Examination
The number 2 cylinder, associated through-bolts, and a threaded stud end held in a nut were sent to the NTSB Metallurgical Laboratory. The examination identified fatigue cracking on both through-bolts and on the threaded end of the stud still in the nut. Damage to the cylinder, piston, and connecting rod was secondary to this fatigue cracking.
The entire engine was further examined at the Lycoming factory under NTSB supervision. The crankcase revealed evidence of welding repairs on the outside of both halves and on interior surfaces near the number 2 cylinder. Lycoming engineering documents specify that welding should not be performed inside the critical cylinder deck area. Hardness measurements in two locations on the number 2 cylinder mounting flange were well below the minimum requirements on all Lycoming crankcase drawings.
The four crankcase through-studs were yellow, unlike the standard silver-gray of Lycoming-manufactured studs. Their threaded length measured 0.66–0.68 inches, below the required minimum of 0.840 inches. One unbroken stud underwent a tensile test, recording 169.4 ksi (maximum load 21,500 pounds). In contrast, a sample of 19 through-studs from 2005–2008 inspected at Lycoming ranged from 172.6 to 180.9 ksi, averaging 177.4 ksi.
Engine Overhaul History
According to the airplane and engine logbooks, the engine was overhauled and reinstalled on January 27, 2006. During overhaul, the crankcase was sent to another facility for work. That facility could not provide records of the performed work. The most recent 100-hour inspection occurred on August 22, 2007, with 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.