What happened
During a post-production test flight, the pilot observed symptoms indicating an uncommanded lean mixture. In response to these engine irregularities, the pilot initiated a turn to return to the airport for a landing. During this transit, the engine suffered a complete loss of power.
While attempting a forced landing off the airfield on the base leg, a fire ignited in the engine compartment. The flames burned through a hydraulic line, which caused the landing gear to extend unexpectedly. This deployment increased the aircraft's glide angle, making it impossible to clear a drawbridge located along the intended flight path.
In an attempt to maneuver around the bridge obstruction, the aircraft entered a stall and mush condition. This resulted in a collision with a boat dock. The pilot, who was the only person on board, sustained serious injuries during the impact.
Findings
An investigation into the mechanical failures identified that a loose fuel line fitting caused a leak within the fuel system. This malfunction led to the initial engine symptoms and the subsequent total loss of power. Furthermore, the investigation determined that improper maintenance or installation by production personnel contributed to the loose fitting. The fire in the engine area was directly responsible for the inadvertent extension of the landing gear, which compromised the aircraft's glide performance and prevented a successful avoidance of the terrain obstruction.