What was found
CAPTAIN REPORTED THAT DURING TAXING TO PLATFORM, THE ELEC LIGHT TURNED ON. MAINTENANCE PERFORMED ELECTRICAL SYSTEM AUTO TEST IAW FIM 24-31, TASK 801 PROCEDURE, SHOWING FAILURE CODE IN P5-13 AND DETECTING THE STATIC INVERTER FAILED. THE STATIC INVERTER WAS REPLACED IAW AMM 24-34-21, TESTED CORRECT. THE AIRCRAFT WAS DISPATCHED AND AIRCRAFT RETURNED TO PLATFORM DUE TO DURING TAXING, THE ELEC LIGHT TURNED ON AGAIN. MAINTENANCE PERFORMED THE ELECTRICAL SYSTEM AUTO TEST IAW FIM 24-31, TASK 801 PROCEDURE, DETECTING THE STATIC INVERTER WITH FAILURE; SO THE STATIC INVERTER WAS REPLACED IAW AMM 24-34-21, TESTED CORRECT. AS PRECAUTIONARY ACTION, THE MAIN BATTERY WAS REPLACED IAW AMM 24-31-11, TESTED CORRECT.