As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BATTERIES LEAKED ACID/ALKALII, CORRODING CONTACTS SERVERLY AND RENDERING ELT INOPERABLE. BATTERIES WERE INSTALLED IN 2006. SHELF DATE ON BATTERIES WERE MAR 2011. ELT WAS NOT FOUND ACTIVATED. THIS IS THE THIRD CASE OF THIS I HAVE SEEN IN 2006/2007 AND THERE HAVE BEEN SEVERAL OTHERS IN THE PAST 5 YEARS. IN ALL CASES THE BATTERIES RENDERED THE ELT INOP PRIOR TO THE REPLACEMENT DATE (HALF OF SHELF LIFE IAW FAR 91.207 (C)). ALL PROBLEMS WERE DETECTED DURING ANNUAL INSPECTIONS OF ELT IAW FAR 91.207 D.