As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A ROUTINE INSPECTION, IT WAS DISCOVERED THAT THE LEFT AFT PLENUM LOWER SKIN HAS CORROSION IN TWO PLACES. FOUND CORROSION OUT OF LIMITS. INSTALLED DOUBLER AND TRIPLER IAW B727 SRM 57-30-3 FIGURE 8. THE AIRCRAFT WAS RETURNED TO SERVICE. (M)