What happened
During a flight intended for post-maintenance inspection, the pilot—who also serves as the owner and is a certified mechanic—was conducting tests on the right engine's fuel injector pump. This process involved calibrating the fuel flow by connecting an external line to the transmitter fitting of the fuel injector. Before commencing the flight, the external line was disconnected and the original fuel flow component was reinstalled.
Roughly ten minutes into the flight, while operating at pressures between 25 and 15 psi, the pilot noticed flames emanating from the engine area. In response to the fire, the pilot successfully shut down the right engine and feathered the propeller. Although the aircraft returned to the ground safely, the pilot was unable to taxi the plane following the landing, which necessitated the abandonment of the aircraft.
Findings
Investigations into the incident identified several contributing factors related to the recent maintenance work. The primary cause was determined to be an improperly installed fuel system line fitting. This error resulted in a leak within the fuel system, which subsequently ignited and caused the engine fire. The findings also noted that the installation performed by the pilot in command was improper.