What was found
R/H HORIZONTAL STAB. LOWER SKIN AT AFT SPAR, FWD OF FWD ROW FASTENERS @ STAB.STA. 101.90 + 4" MARKED 1.550"L CRACK FOUND. GROUNDED - YES. REPAIRED HORIZONTAL STAB. LOWER SKIN AND RIB FITTING IAW B737-800 SRM 55-10-01-2R-11 REPAIR 11 AND ALASKA EA 800-55EA-23337 REV 00 DATED 3/31/2021. LOWER SKIN REPAIR IS A CAT B REPAIR AND REQUIRES RE-INSPECT AT56,000 FLIGHT CYCLES. RIB FITTING REPAIR IS A CAT A REPAIR IAW FAA FORM 8100-9.