What was found
CORROSION AT CTR WING TANK LOWER SURFACE, INSIDE RT A/C BAY PLENUM, APPROX BS 830. REMOVED FASTENERS FOR ACCESS AS PER B 727 SRM 51-30-2. REMOVED RT PRIMARY 7 SECONDARY HEAT EXCHANGER AND PLENUM ASY FOR S/M ACCESS B 727 MM 21-50-2. REMOVED CORROSION AT CENTER WING TANK LWR SURFACE I/B A/C PLENUM FROM STA 830 TO 839 RBL 32 TO 23 US/PER B 727 SRM 51-10- 6. PERFORMED HFEC, INSPECTION AT AREA PER NDT PART 6,51-00-00 FIG 4, NO DEFECTS NOTED. PERFORMED THICKNESS CHECK OF LWR SKIN BS 830 TO 839.0 RBL 32 TO 23 PER PARAMETRICS MANUAL NR 910-131B, LOWEST READINGS. 109, SEVERAL AREAS OUT OF LIMITS. REMOVED INTERNAL DOUBLER RBL 32 TO RBL 13 STA 830 AS PER B 727 SRM 51-30-2.