CHI99LA352

The airplane was in level cruise flight at 2,500 feet msl, 85 knots, 2450 RPM, and heading 020 degrees toward Camdenton, Missouri, when the airplane's engine 'began running rough with RPM drop to 1500-1600.' The pilot said he applied carburetor heat, raised the nose of the airplane to minimize the altitude loss, and started heading toward Lebanon, Missouri. By leaning the mixture, the pilot was 'able to bring the engine RPM up to 1600-1700.' The pilot contacted the approach control at Springfield, Missouri, and informed them of their situation. The pilot said that the RPM began decreasing again. He placed the mixture to full rich, but noticed no change in performance. Then the engine stopped. The pilot said he maintained a 50-55 knot glide until the airplane impacted into a heavily wooded area. Examination of the airplane's engine showed that the shaft supporting the number 3 cylinder rocker arm had broken off. Examination of the remaining airplane systems showed no anomalies.

On September 5, 1999, at 2045 central daylight time (cdt), a Cessna 150M, N63668, operated by a private pilot, sustained substantial damage when during a forced landing into a heavily wooded area, 13 miles southwest of Lebanon, Missouri, the airplane impacted into a tree. Preceding the forced landing, the airplane experienced a complete loss of engine power while in cruise flight. Night visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted on a VFR flight plan under 14 CFR Part 91. The pilot and pilot-rated passenger on board reported no injuries. The cross-country flight originated at Springfield, Missouri, at 2020 cdt, and was en route to Camdenton, Missouri.

In his written statement, the pilot said they were in level cruise flight at 2,500 feet mean sea level, 85 knots, 2450 RPM, heading 020 degrees toward Camdenton, when the airplane's engine "began running rough with RPM drop to 1500-1600." The pilot said he applied carburetor heat, raised the nose of the airplane to minimize the altitude loss, and started heading toward Lebanon, Missouri. By leaning the mixture, the pilot was "able to bring the engine RPM up to 1600-1700." The pilot contacted Springfield Approach Control and informed them of their situation. The pilot said that the RPM began decreasing again. He placed the mixture to full rich, but noticed no change in performance. Then the engine stopped. "There was no fire, smoke, oil shower, or noise. The attempted restart failed." The pilot said he maintained a 50-55 knot glide until they could see the ground. The terrain was entirely wooded. The pilot maintained a glide speed at just over zero-flap stall speed until the airplane impacted into the dense tree tops.

The Federal Aviation Administration (FAA) Radar Approach Control facility at the Springfield-Branson Regional Airport, indicated that the airplane at 14 miles southwest of the Lebanon-Floyd W. Jones Airport, Lebanon, Missouri, when the pilot contacted them reporting that the airplane's engine was running rough. The airplane was approximately 11 miles southwest of the Lebanon- Floyd W. Jones Airport, when the pilot reported that the airplane had lost power. Radio and radar contact with the airplane was lost 13 miles southwest of the Lebanon-Floyd W. Jones Airport.

An FAA inspector examined the airplane at Paola, Kansas. The airplane's upper cowling was crushed inward on the top and right side. The windscreen was broken out. The airplane's right wing was bent down and aft. The upper wing skin showed heavy buckles. The right wing leading edge showed a 15-inch wide, "C"-shaped, inward dent beginning at the wing strut attachment bolt and running inboard. The aft fuselage was broken laterally, approximately 3 feet aft of the baggage compartment. The empennage was twisted left approximately 100-degrees. The leading edge of the left horizontal stabilizer was crushed aft. The top of the vertical stabilizer and rudder was bent slightly right. Flight control continuity was confirmed.

The airplane's engine was examined by an airplane and powerplant mechanic at Payola, Kansas. The examination showed that the shaft supporting the number 3 cylinder rocker arm had broken off.

Examination of the remaining airplane systems showed no anomalies.