What was found
DURING HEAVY MAINTENANCE, EPSU BATRERY PACKS 10WL, 11WL, 12WL, 13WL FAILED OPERATIONAL CHECK; REF IAC N/R 13147-5802, R&R EPSU BATTERIES IAW AMM TASK 33-51-38-000-002, 33-51-38-400-002 OPS CHECK GOOD. 10WL: P/N OFF & ON 3214-31, S/N OFF 781924, S/N ON 811574 11WL :P/N OFF & ON 3214-31, S/N OFF 052637, S/N ON 838999 12WL : P/N OFF &ON 3214-31, S/N OFF 780620, S/N ON 834596 13WL : P/N OFF &ON 3214-31, S/N OFF 777451, S/N ON 834607.