FTW04LA065

The 380-hour pilot reported that during cruise flight he heard "the engine make two loud knocking sounds and it started to vibrate and loose power." The pilot initiated a forced landing to an unlit airfield east of his position. During the landing roll, he realized he "wouldn't be able to stop the airplane before running into trees located at the end of the runway." The pilot turned the airplane left, exiting the runway. Subsequently, the airplane impacted a ditch, nosed over, and came to rest inverted. During an on-scene examination of the airplane, the engine was started and it ran for approximately 15 seconds before it was turned off with the magneto switch. When the propeller was manually rotated by hand, valve train continuity was established throughout, and all four cylinders produced compression. No mechanical deficiencies were noted, and the reason for the loss of engine power was undetermined.

On January 25, 2003, at 1855 central standard time, a Cessna 120 tailwheel equipped single-engine airplane, N1961V, was substantially damaged during a forced landing following a loss of engine power at the Country Air Estates Airport, near Lonoke, Arkansas. The private pilot, sole occupant of the airplane, was not injured. The airplane was registered to and operated by the pilot. Twilight visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight. The cross-country flight departed from the Stuttgart Municipal Airport, near Stuttgart, Arkansas, at 1835 and was destined for the North Little Rock Municipal Airport, near Little Rock, Arkansas.

The 380-hour pilot reported in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) that while in cruise flight at 1,300 feet msl, he heard "the engine make two loud knocking sounds as it started to vibrate and lose power." He initiated a forced landing to an unlit airfield located approximately 1/4 mile east of his current position. During the descent, he "performed an emergency checklist and was unable to remedy the problem." The pilot stated he was directly over the east/west runway and elected to land on runway 36 (a 2,500 foot long, 100 foot wide grass runway). During the landing roll, he realized he "wouldn't be able to stop the airplane before running into trees located at the end of the runway." The pilot intentionally turned the airplane left, exiting the runway. Subsequently, the main landing gear impacted a ditch that ran parallel to the runway. The airplane nosed-over, and came to rest inverted.

Examination of the airplane by the Federal Aviation Administration (FAA) inspector, who responded to the accident site, revealed the left forward wing spar was bent, the vertical stabilizer sustained structural damage, and the fuselage, aft of the main landing gear, was wrinkled.

On February 24, 2003, at the facilities of 92nd West Aviation Inc., of Lonoke, Arkansas, the engine was inspected under supervision of the FAA inspector. The Continental C-85-12F engine was started and ran for approximately 15 seconds before it was turned off with the magneto switch. When the propeller was manually rotated by hand, valve train continuity was established throughout, and all four cylinders produced compression. According to the NTSB Form 6120.1/2, the airplane's most recent annual inspection was completed on September 1, 2003, with an airframe total time of 3,348.4 hours and engine total time of 4,605.1 hours. At the time of the accident, the engine and airframe had accumulated a total of 530.5 hours since the last inspection.

The reason for the loss of engine power was undetermined.