What was found
MCN - MAJOR REPAIR - DURING C-20 CHECK .3125 INCH CRACK WAS FOUND IN LT CENTER CABIN FLOOR PANEL SUPPORT CHANNEL AT BS 540, BL -0-, WL 208. MAINTENANCE REMOVED CRACKED FLOOR CHANNEL AT BS 540, FROM BL -0- TO LBL 25, WL 208; FABRICATED A NEW REPLACEMENT CHANNEL; INSTALLED REPAIR PART IAW B737-300 SOPM 20-50-01 FIG 1 PG 1-8.