A test flight was cut short after a fire warning came on indicating a problem with one of the four engines on an aircraft. A visual examination following the precautionary landing revealed several burned hoses, a melted bolt, and fuel leaking from the base of the main burner. The fuel nozzle was also damaged, and based on its microstructure, came very close to melting. Investigators determined that the burner was mounted backwards, facing the compressor rather than the turbine. They also recommended a redesign to prevent the fuel nozzle from being reversed.