What was found
WHILE PERFORMING AILERON CABLE REPLACEMENT, A FUEL LEAK WAS NOTED ON THE LEFT WING AROUND RIB 10, AFT SPAR. MAINTENANCE PERFORMED A LEAK CHECK TO SEE WHERE THE FUEL WAS COMING FROM PER EMB 170 AMM. AFTER THE OPENING OF THE FUEL TANK PANEL THEY DISCOVERED A 4CM CRACK AROUND A FASTENER. THIS WAS CONFIRMED WITH NDT TO BE A CRACK. THE CRACK IS LOCATED ON THE LEFT WING, INBOARD OF RIB 10 ON THE LOWER WING SKIN AFT SPAR AROUND A FASTENER. EMBRAER ISSUED TWO ETD'S FOR THE REPAIR OF THIS WING ETD2012-170/0717 & ETD2012-170/03018. THIS WAS ACCOMPLISHED AS A MAJOR REPAIR.