Accident Summary
On December 12, 2015, at approximately 1200 eastern standard time, a DeHavilland Tiger Moth DH-82A, registration N9410, was substantially damaged during a forced landing shortly after departure from Old Orchard Airpark (2NK9) in Modena, New York. The pilot and a passenger were not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the personal flight conducted under 14 CFR Part 91.
Preflight and Takeoff
The pilot reported performing a pre-takeoff engine run that included an operational check of the magnetos, with no anomalies noted. After takeoff from runway 18, during the initial climb, the engine experienced a 200-rpm reduction in power. The pilot attempted to return to the runway, but the airplane could not maintain altitude and struck trees approximately one-quarter mile from the airport.
Aircraft and Engine Details
The airplane was manufactured in 1940 and equipped with a DeHavilland Gipsy Major 1C engine rated at 145 horsepower. Postaccident examination by a Federal Aviation Administration inspector revealed substantial damage to both wings, the empennage, and the fuselage. When the inspector rotated the engine crankshaft, continuity was observed to the accessory section, and compression was attained on all cylinders except the forward (No. 1) cylinder, which produced little to no compression. Due to the engine's disposition, the ignition system could not be checked for proper operation, and no further examination of the engine was conducted.
Postaccident Findings
The pilot subsequently reported that a teardown of the engine revealed the No. 1 cylinder exhaust valve was stuck in the open position. Additionally, disassembly of the left magneto disclosed a fractured breaker spring. The pilot stated that the loss of compression on one cylinder alone would have necessitated a forced landing, but he believed the combination of the compression loss and the magneto failure resulted in the loss of engine power experienced during the accident flight.