NTSB Factual Report

On June 4, 2011, approximately 1415 central daylight time, a Boeing A75N1 (PT17) airplane, N50052, impacted a tree and a house near Freeman Field Airport (K3JC), Junction City, Kansas. The commercial pilot and passenger were not injured and the airplane was substantially damaged. The airplane was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The flight was originating at the time of the accident.

The pilot reported that there was a loss of engine power shortly after departure. He was anticipating an rpm of 1,800 to 1,850; however, the tachometer indicated 1,700 rpm and the rpm was decreasing. The pilot altered his heading by 10 degrees to avoid higher obstacles; however, the airplane impacted a tree and a house before a forced landing site could be located. Both wings were crushed, bent, and broken during the impact sequence.

The Federal Aviation Administration (FAA) inspector who attended the engine examination reported that the number six cylinder had a measured compression of 34/80 and that an air leak into the exhaust stack could be heard. In addition, the ignition timing on the forward bank of spark plugs was delayed by 2.5 degrees and the ignition timing on the rear bank of spark plugs was delayed by 5 degrees, resulting in a degradation of engine power. Further examination of the airframe confirmed control continuity to all flight controls.

According to both the FAA and the pilot, the airplane was loaded to within 150 pounds of the airplane's gross take-off weight. Calculations of relevant meteorological data revealed that the density altitude was 3,350 feet.

NTSB Probable Cause

The degraded engine performance due to low compression on the cylinder and delayed ignition timing.