What was found
L/H WING FUEL TANK PANEL HAS RUNNING LEAK, 521AB. REMOVED FROM SERVICE. COMPLETED WING FUEL TRANSFER FROM LH TO RH WING IAW AMM TASK 28-20-00-910-801-A. REMOVED PANEL 521AB IAW E175 AMM 28-11-03-000-801-A STEP 9(D). R&R WITH SERVICEABLE FROM STOCK PANEL 521AB RUBBER SEAL IAW E175 AMM 28-11-03-000/400-802-A. REPLACED KNITTED GASKET & INSTALLED PANEL 521AB IAW E175 AMM TASK 28-11-03-400-801-A STEPS 9.C.A-14. COMPLETED A WING-TO-WING FUEL TRANSFER FROM RH WING TO LH WING IAW E175 AMM TASK 28-20-00-910-801-A STEPS 7.B.1-6 & STEP 8.A-D. NO FURTHER LEAKAGE DETECTED. NO FURTHER DEFECTS NOTED. RETURNED TO SERVICE.