What happened
On June 28, 2023, a pilot was performing training maneuvers at the Sławno airfield in Poland. The flight involved two circuit patterns in a Siemens Schuckert D-1 replica, registration SP-SYAN. This was the pilot's first flight in the aircraft following a recent maintenance overhaul and test flights conducted by a certified inspector.
After completing the first circuit and a low pass over the runway, the pilot entered a left turn. During this maneuver, the aircraft disappeared from the view of the aircraft owner, who was observing from a nearby vehicle. Approximately one hour after takeoff, the aircraft was reported missing to the police. The wreckage was located near midnight within the circuit area, wedged among tall trees.
Investigation of the wreckage revealed that the aircraft struck the ground at a steep angle of approximately 70 degrees, impacting the nose and left wing first. The impact caused the fuselage to break behind the cockpit. The pilot sustained fatal injuries at the scene. There was no evidence of alcohol consumption in the pilot's system.
The investigation
Investigators examined the wreckage and the aircraft's recent maintenance history. The aircraft had recently undergone a major renovation performed by the pilot. During this renovation, the original oval metal fuel tank, which featured a design ensuring continuous fuel flow, was replaced with a rectangular "Hulk" fuel tank intended for use in motorboats.
Technical examination of the fuel system showed that while some fuel remained in the fuel filter and the cockpit sediment bowl, the float chamber of the first carburetor was empty and lacked a drain plug. The investigation focused on how the new tank's design influenced fuel delivery during flight maneuvers.