Accident Details
On April 3, 2012, at approximately 1400 eastern daylight time, a Piper PA-28R-200, registration N961JD, sustained substantial damage during a forced landing at McEntire Joint National Guard Base (MMT) in Eastover, South Carolina. The private pilot and passenger were not injured. Visual meteorological conditions prevailed, and the flight was not operating on a flight plan. The personal flight originated from Barnwell Regional Airport (BNL), South Carolina, bound for Tappahannock-Essex County Airport (XSA), Virginia, under Part 91.
According to the pilot, the previous evening he added one quart of oil to the engine. In the morning, prior to the first flight from Lakeland Linder Regional Airport (LAL), Florida, to BNL, he performed a complete preflight inspection. After arriving at BNL and refueling, he conducted another walk-around inspection. The flight departed BNL about 1330. Approximately 25 minutes later, the Lycoming IO-360-C1C engine began running rough. The pilot checked the magnetos and noted that all cylinder head and exhaust gas temperatures were normal. He reduced power, but the roughness increased and oil pressure dropped to zero within about one minute.
The pilot planned to divert to Columbia Metropolitan Airport (CAE) but saw MMT while at 1,500 feet and decided to land on runway 32. Due to the rapid development of the forced landing, he did not have time to change to the tower frequency. As he approached, he observed an F-16 take off from runway 14, followed by another. The accident airplane encountered wake turbulence from the second F-16 and rolled about 45 degrees. The pilot recovered to wings level at about 100 feet above ground level but lacked sufficient altitude to align with the runway. He landed at a 20- to 30-degree angle, veered off the right side, and to avoid a terrain drop-off, aligned parallel to the runway but struck a "runway remaining" sign at about 50 mph before stopping.
After exiting, the pilot observed engine oil covering the nose landing gear and gear doors.
Engine Examination
The responding Federal Aviation Administration (FAA) inspector examined the engine and found that the #1 cylinder upper aft through bolt was sheared off, two #1 cylinder upper mounting studs had pulled loose from the crankcase, and the crankcase at the #1 cylinder aft lower through bolt was cracked, with an oil leak in that area. The engine halves and through bolts were later examined at Lycoming Engines. The examination confirmed the #1 cylinder upper aft through bolt was broken. Internally, the crankcase halves exhibited pitting and a frosty appearance on the #2 and #3 upper main bearing support webs, consistent with fretting. According to FAA publication 8083-30, fretting occurs when two mating surfaces, normally at rest, are subject to slight relative motion, characterized by pitting and generation of finely divided debris.
Maintenance History
Maintenance records indicated that at airplane tachometer time 2,958, the engine underwent a major overhaul by Zephyr Aircraft Engines, signed off July 29, 2002, which included an engine crankcase overhauled by CSI, Incorporated. On January 9, 2007, at tachometer time 3,448, a hairline crack was found in the crankcase. The engine was disassembled by Zephyr and reassembled with a rebuilt crankcase from CSI. On September 12, 2010, at about tachometer time 3,751, after arrival at Lubbock Preston Smith International Airport (LBB), Texas, Lubbock Aero found that one intake pipe was loose on cylinder #1, one on cylinder #2, and one exhaust nut was missing from cylinder #1. Five cylinder hold down studs were also found broken on cylinder #2. The missing nut was replaced, the intake pipes were resealed, cylinder #2 was removed and its studs replaced, then reinstalled, followed by a successful engine run.
Commentary from Sport Aviation
In the June 2014 issue of Sport Aviation, the "Savvy Aviator" column noted that a veteran mechanic and expert witness stated the root cause of issues such as spun bearings, thrown rods, and separated cylinders is a failure to achieve sufficient preload in assembled fasteners. Preload refers to the clamping force created by tightening a fastener. The article highlighted five obstacles to achieving proper preload during cylinder installation on an engine mounted on an airplane: fasteners not new, inadequate lubrication, poor lubricant quality, limited wrench access, and incomplete manufacturer instructions. The complete article is in the public docket for this accident.