What was found
SB 500-27-004, REV B, AILERON JOINT ASSY INSP AND REPLACEMENT. THIS SB HAS PROCEDURES FOR INSPECTING/TESTING BOTH WINGS, AILERONS JOINT ASSEMBLIES. REPLACING THE AILERON JOINT ASSY, WHENEVER THE AILERON FAILS A "FRICTION" TEST. THE ASSY FAILS TESTING WHEN THE BELLCRANK IS CORRODED AND FROZEN IN THE BEARING OF THE FITTING ASSY. THIS IS DUE TO CORROSION FROM DISSIMILAR METALS. SINCE THIS IS JUST A SB, SUGGEST THIS INSP BE UPGRADED TO AN AD TO PREVENT POSSIBLE AILERON MALFUNCTIONS FROM ACFT NOT COMPLYING WITH THE SB.