What happened
On July 9, 2016, a Starduster Too (registration EC-XJT) was performing a local flight from the Robledillo de Mohernando airfield (LERM) in Guadalajara, Spain. The aircraft was carrying one pilot and one passenger.
Shortly after takeoff from runway 01, the pilot detected a loss of engine power while attempting to transition from the climb to level flight. Unable to maintain altitude, the pilot executed an emergency landing in a recently plowed field approximately 100 meters beyond the end of the runway. While the pilot managed to land the aircraft in a three-point attitude, the soft, freshly tilled soil caused the main landing gear to sink. This led to the collapse of the gear, the nose of the aircraft digging into the ground, and a subsequent nose-over (capsize). Both the pilot and the passenger were uninjured and were able to exit the aircraft on their own.
The investigation
The CIAIAC investigation focused on determining the cause of the engine power loss. Investigators examined the aircraft's engine, a Lycoming O-435, and performed several tests. A fuel analysis was conducted to check for water contamination, which yielded negative results. The magnetos were removed and tested on a bench; while they functioned correctly, investigators noted signs of overheating and oxidation.
Further examination of the engine components revealed that the air intakes and filters were clogged with soil from the impact site. The investigation also reviewed the aircraft's maintenance and usage history, noting that the engine had experienced long periods of inactivity. Additionally, the investigation looked into the compatibility of installed components, such as the oil filter and magneto system, noting they were not the specific models recommended by the engine manufacturer.
Findings
- The engine did not stop running entirely, but the pilot perceived a significant loss of power.
- The aircraft's landing gear collapsed because the plowed field terrain was too soft to support the impact.
- The engine was a Lycoming O-435, a model not specifically recommended by the aircraft kit manufacturer, who suggested the Lycoming O-360 or IO-540 instead.
- The aircraft had experienced long periods of inactivity, which the engine manufacturer warns can lead to internal corrosion and reduced performance.
- The use of non-recommended components, such as certain oil filters and magneto systems, may have contributed to the engine not developing its expected power.
- The investigation could not establish a conclusive cause for the initial power loss, but identified that improper engine development was likely influenced by irregular usage and non-standard components.