Incident Overview
During an approach to land, the pilot of an amphibious aircraft extended the landing gear and performed prelanding checks. While descending, the pilot observed an excessive loss of altitude and attempted to add power. However, the engine did not respond, and the pilot was unable to restart it. Subsequently, the aircraft touched down on the lighting system short of the runway and nosed over.
Examination Findings
An examination of the aircraft revealed that the low pressure relief valve adjusting screw on the fuel pump (part number 638154-1) was worn and recessed in the housing. The condition of the screw allowed it to rotate, which could vary the low pressure fuel setting.
Probable Cause
The low pressure relief valve adjusting screw on the fuel pump was worn and recessed in the housing, causing the screw to rotate and vary the low pressure fuel setting.