What happened
The pilot was conducting an approach to land in an amphibious aircraft. During the descent, the pilot extended the landing gear and completed prelanding checks. While descending, the pilot noticed an excessive loss of altitude and attempted to add power to recover. However, the engine did not respond to the input, and the pilot was unable to restart it. Subsequently, the aircraft touched down on the lighting system short of the runway and nosed over.
The investigation
An examination of the aircraft revealed that the low pressure relief valve adjusting screw on the fuel pump (PN 638154-1) was worn and recessed in the housing. This wear allowed the screw to rotate, which varied the low pressure fuel setting. This mechanical failure prevented the engine from receiving the necessary fuel pressure during the critical phase of flight.
Findings
The primary contributing factor was the fuel pump malfunction due to a worn adjusting screw. The pilot's inability to obtain power or restart the engine led to the loss of control and subsequent crash. The aircraft sustained significant damage upon impact with the runway lighting system.