What was found
FOUND FUEL SYSTEM CONTAMINATED WITH AN UNKNOWN SUBSTANCE. AFTER HAVE THE ENTIRE SYSTEM DRAINED, FLUSHED AND THE ENGINE FUEL INJECTION SYSTEM OVERHAULED, THE AIRCRAFT WAS REFUELED AND FLOWN. AFTER A SHORT FLIGHT, THE SUMPS WERE CHECKED AGAIN AND THE SUBSTANCE WAS FOUND AGAIN. BOTH FORWARD FUEL CELLS WERE REMOVED FROM THE AIRCRAFT. THE SPONGE-LIKE MATERIAL INSIDE THE WING ROOT HEADER TANK PORTION OF THE FUEL CELL WAS FOUND IN A DETERIORATED CONDITION AND CONTAMINATING THE ENTIRE FUEL SYSTEM. NEW FUEL CELLS WERE ORDER. (K)