MIA06LA056

The pilot stated that after takeoff the flight proceeded to a location called the "Villages" then he made a right turn and elected to return to the departure airport. He reported that he was on the west side of Lake Griffin and approximately 3 miles from the destination airport when the engine began to run rough. He reduced throttle control but the engine continued to run rough. He checked the magnetos and verified the mixture control was full rich which had no effect. He discontinued the approach and began a right descending turn not wanting to fly over the lake. He noted that something inside the engine compartment hit the engine cowling, and he looked for a place to land. He banked to the right and after spotting an opening, he lowered the flaps but overshot the intended landing area. While descending he noted a telephone pole straight ahead and applied left rudder to avoid the pole but the right wing collided with the pole. The head of the No. 4 cylinder separated from the barrel due to fatigue cracking. A review of the maintenance records revealed that the engine was overhauled on November 2, 1993. On June 1, 1999, the No. 4 cylinder was removed, repaired, and installed. The No. 4 cylinder had accumulated 1,076.9 hours since installation after repair.

On February 18, 2006, about 1715 eastern standard time, a Cessna 150L, N5262Q, registered to Changing Horses LLC, and operated by an individual, collided with a telephone pole then the ground while descending for a forced landing near Fruitland Park, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 91 personal, local, flight from Leesburg Regional Airport, Leesburg, Florida. The airplane was substantially damaged and the private-rated pilot and one passenger sustained serious injuries. The flight originated about 30 minutes earlier from Leesburg Regional Airport.

The pilot stated that after takeoff the flight proceeded to a location called the "Villages" then he made a right turn and elected to return to the departure airport. He reported that he was on the west side of Lake Griffin

and approximately 3 miles from the destination airport when the engine began to run rough. He reduced throttle control but the engine continued to run rough. He checked the magnetos and verified the mixture control was full rich which had no effect. He discontinued the approach and began a right descending turn not wanting to fly over the lake. He noted that something inside the engine compartment hit the engine cowling, and he looked for a place to land. He banked to the right and after spotting an opening, he lowered the flaps but overshot the intended landing area. While descending he noted a telephone pole straight ahead and applied left rudder to avoid the pole but the right wing collided with the pole. The airplane then impacted the ground.

Examination of the engine by an FAA airworthiness inspector revealed the head of the No. 4 cylinder was separated from the barrel and only remained secured to the engine by the ignition leads. The No. 4 cylinder was retained for further examination.

The No. 4 cylinder was examined at the NTSB Materials Laboratory located in Washington, D.C. The result of the examination revealed the cylinder was fractured through the steel barrel between the third and fifth fins. Magnified examination of the fracture surface revealed "... curved beach marks over a large portion of the fracture indicative of fatigue cracking." The orientation of the beach marks indicated fatigue initiation on the outer diameter of the barrel between the third and fourth fins from the head; on the intake valve side of the barrel. No damage or corrosion was apparent in the origin region. The fatigue extended circumferentially in both directions for more than half of the barrel circumference.

A review of the maintenance records revealed that the engine was overhauled on November 2, 1993. On June 1, 1999, the No. 4 cylinder was removed, repaired, and installed. The No. 4 cylinder had accumulated 1,076.9 hours since installation after repair.

The airplane minus the retained No. 4 cylinder was released on April 4, 2006, to Buck Williams, of Sample International Aviation, Inc. The retained No. 4 cylinder was also released to Buck Williams on June 22, 2007.