Accident Sequence
During a post-production test flight, the pilot noted symptoms of an uncommanded lean mixture and turned to return for landing. En route to the airport, the engine lost power completely. On base leg for a forced landing off airport, a fire broke out in the engine area and burned through a hydraulic line, causing the landing gear to extend. Due to an increased glide angle, the planned flight path would not clear a drawbridge obstacle. When the pilot maneuvered to avoid the obstacle, the aircraft stalled, mushed, and collided with a boat dock. The pilot, sole on board, was seriously injured.
Investigation Findings
Investigation revealed a loose fuel line fitting. The official findings identified the following occurrences:
- Occurrence #1: Loss of engine power (partial) due to mechanical failure/malfunction. Findings: (c) fuel system, line fitting - loose; (c) maintenance, installation - improper - production/design personnel.
- Occurrence #2: Loss of engine power (total) due to mechanical failure/malfunction during maneuvering turn to landing area (emergency).
- Occurrence #3: Forced landing during descent (emergency).
- Occurrence #4: Fire during maneuvering turn to landing area (emergency). Findings: (c) fuel system, line fitting - leak; (f) fluid, fuel - fire.
- Occurrence #5: In flight collision with terrain/water during descent. Findings: (f) landing gear, normal retraction/extension assembly - burned; (f) landing gear - deployed inadvertently; (f) proper descent rate - not possible - pilot in command; (f) terrain condition - high obstruction(s); (f) maneuver - attempted - pilot in command; (f) terrain condition - none suitable; (f) stall/mush - inadvertent.
Probable Cause
The probable cause, as stated in the official findings, encompasses multiple factors: a loose fuel line fitting due to improper installation by production/design personnel led to a fuel leak and partial then total engine power loss. The subsequent fire and forced landing, combined with terrain obstacles and an inadvertent stall, resulted in the collision with the boat dock.