Philadelphia, PA, USA
N901AV
Piper PA-28RT-201
During the takeoff, the pilot heard a loud noise and the engine began to vibrate "severely." The pilot realized that it would not be possible to return to the airport, and elected to land straight ahead. The airplane came to rest approximately 500-700 feet beyond the departure end of the runway. Examination of the airplane revealed that the engine's number 3 cylinder had separated from the engine case. Examination of the number 3 cylinder revealed that it had separated from the engine due to fatigue of the cylinder attachment studs and both through bolts. The fatigue initiated in the lower aft stud and progressed to the other studs and bolts. The engine had accumulated 1,407 total hours of operation since its most recent overhaul.
On April 9, 2006, about 1030 eastern daylight time, a Piper PA-28RT-201, N901AV, was substantially damaged during a forced landing after takeoff from Northeast Philadelphia Airport (PNE), Philadelphia, Pennsylvania. The certificated private pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the 14 CFR Part 91 personal flight. On the morning of the accident, the pilot completed a preflight inspection, and an engine run-up, both per the checklist, noting no anomalies. He then taxied onto the runway, slowly advanced the throttle, and observed that the engine gauges were "normal." When the airplane reached rotation speed, the pilot initiated a climb, and shortly thereafter retracted the landing gear when no usable runway remained. As the landing gear retracted, there was a loud noise and the engine began to vibrate "severely." The pilot immediately checked the engine gauges and cycled the landing gear back to the down and locked position. Realizing that it would not be possible to return to the airport, the pilot elected to land straight ahead, and completed an emergency-landing checklist. The airplane came to rest approximately 500-700 feet beyond the departure end of the runway. During the landing roll, the landing gear collapsed resulting in substantial damage. A Federal Aviation Administration (FAA) inspector examined the airplane at the scene. Examination of the engine revealed that the number 3 cylinder had separated from the engine case. The piston and connecting rod were found in the forward section of the engine cowling, and the rod end cap was found on the runway near the 6,000-foot distance marker. The engine was disassembled, and the right engine case half, number 3 cylinder, number 3 cylinder through bolts, connecting rod end, connecting rod end bolts, and connecting rod journal bearings were forwarded to the safety board materials laboratory for further examination. According to the materials laboratory report, examination of the right engine case half revealed that the area around the number 3 cylinder opening was deformed and gouged consistent with cylinder separation and contact with moving parts after cylinder separation. All of the number 3 cylinder studs were fractured between about .4 and .45 inches from the case surface. The fracture surfaces of each stud, and both through bolts, exhibited features consistent with fatigue. The fracture surface of the lower, most aft stud, exhibited relatively smooth features on multiple planes across the fracture surfaces, consistent with fatigue under relatively low stress. The fractures initiated from multiple origins around the circumference of the stud. The two studs on either side of the lower aft stud exhibited relatively smooth features in a flat plane across between about 85 and 90 percent of the fracture surface consistent with fatigue. The fractures of those studs initiated from multiple origins near the cylinder side of the studs. The remaining 3 studs exhibited somewhat rougher features in a flat plane across about 60 to 75 percent of the fracture surface, consistent with fatigue under relatively high stress. The fractures initiated from multiple origins at the cylinder side of the studs, but more toward the aft side of the studs than in the two previously mentioned studs. Examination of the fracture surfaces of both through bolts revealed that about 10 to 20 percent of the fracture surfaces exhibited relatively smooth features on a flat plane, transitioning to relatively rough features on a slant plane with arrest marks. Features consistent with fatigue and arrested fast fracture under relatively high stress, and multiple fatigue origins were observed. The accident airplane was a Piper PA-28RT-201, and was manufactured in 1980. Examination of the airplane's maintenance logs revealed that it had accumulated 6,846 total hours of operation at the time of the accident. The engine's most recent overhaul was completed on July 7, 2003. Since that date the engine had accumulated 1,407 total hours of operation. The pilot held a private pilot certificate with a rating for airplane single engine land. His most recent FAA second-class medical certificate was issued on May 11, 2005. At the time of the accident, the pilot had 308 total hours of flight experience and 29 hours in the make and model of the accident airplane. The weather reported at Northeast Philadelphia Airport included wind from 010 degrees at 11 knots, visibility 10 statute miles, clear skies, temperature 43 degrees Fahrenheit, dewpoint 25 degrees Fahrenheit, and an altimeter setting of 30.14 inches of mercury.
A fatigue failure of the number 3 cylinder attachment studs, which resulted in a loss of engine power and subsequent forced landing.
Source: NTSB Aviation Accident Database
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