Event Details
During a sprayer calibration test, the engine of the aircraft sustained a substantial loss of power while the pilot was operating about 50 feet above ground level. The pilot determined that the altitude was too low to troubleshoot the power loss and maneuver to an open field. The aircraft touched down in soft mud. Upon landing, the left main gear dug into the mud and collapsed, causing the left wing to impact the terrain. The aircraft then rotated approximately 80 degrees about the left wing before coming to a stop.
Post-Accident Examination
An examination of the aircraft after the accident revealed that the engine would not sustain power at idle or any power setting when the fuel boost pump was in the OFF position. Further investigation of the fuel system found that the B-nut on the fuel line connecting the firewall to the back of the engine was loose. No other aircraft or engine anomalies were detected.
Resolution
After the loose B-nut was tightened, the engine performed without hesitation at all power settings with the fuel pump in the OFF position, confirming that the loose connection was the source of the power loss.