What was found
LT HORIZONTAL LOWER SKIN CRACKED AT STA 175, 10 INCHES FROM TRAILING EDGE. GROUNDED-YES. CUT OUT DAMAGE AND REPAIRED LT HORIZ LOWER SKIN, IAW B737-800 SRM 55-10-01-2R-11 REPAIR 11. THIS IS A CATEGORY B REPAIR WITH AN INSPECTION THRESHOLD OF 56,000 TOTAL FLIGHT CYCLES AND 9,000 FLIGHT CYCLE INTERVALS.