What was found
ENG TORCHING ON START DURING GROUND MAINT TEST RUN. SEVERAL COMPOSITE PANELS LT WING T/E BOTTOM OF WING JUST AFT AND TO BOTH SIDES ON NR 1 ENG HAVE HEAT DAMAGE. FUEL METERING UNIT (FMU) WAS REPLACED, COULD NOT FIND FAULT WITH UNIT. FMU PASSED AS-RECEIVED TEST. NOTHING UNUSUAL WAS FOUND, ALL PARTS AND ALL PACKINGS/RINGS WERE IN GOOD CONDITION WITH LITTLE OR NO WEAR. THE SEALING SURFACES OF THE FMU MPSOV AND ITS MATING SURFACE IN THE HOUSING HAD NO SIGNS OF DAMAGE OR EXCESSIVE WEAR. THE CAUSE OF TORCHING IS UNKNOWN.