What was found
ELT FAILED OPS CHECK. REMOVAL AND INSPECTION REVEALED 2 D CELL BATTERIES LEAKING PROFUSELY. UNIT WAS CLEANED AND INSPECTED AND ALL CELLS WERE REPLACED, EXPIRATION DATES WERE 2017. BATTERY EXPIRATION DATES WERE ALL 2019. 6 (SIX) MONTHS LATER THE ELT WAS AGAIN INSPECTED, THIS TIME, ALL 8 BATTERIES WERE LEAKING AND THE DEVICE HAD DAMAGE ON THE CIRCUIT BOARD AS WELL AS BATTERY CONTACTS. DEVICE WAS REPLACED WITH A 406 MHZ UNIT FROM ANOTHER MANUFACTURER. RECOMMEND FAA/MFR MODIFY ICA TO PERMIT BATTERIES AS IT APPEARS THAT BATTERY QUALITY HAS DANGEROUSLY DETERIORATED OVER THE PAST SEVERAL YEARS.