What was found
THE CHANNEL CLIP, PN 146N8769-24, AND ATTACHING ANGLE, PN 146N8722-41, IN THE R4 DOOR LWR SILL, ARE CORRODED BEYOUND ALLOWABLE LIMITS AND BS 1645. THE CHANNEL CLIP. PN 146N8769-24 AND ANGLE, PN 146N8722-41, WERE REMOVED AND REPLACED AT BS 1645, R4 DOOR LWR SILL, IAW SRM 51-40-02. ORIG MATL THICKNESS; .071", AFTER REWORK; .041", FOR BOTH PARTS. FOUND TO BE OUT OF LIMITS IAW SRM 53-60-15. THIS REPAIR IS CLASSIFIED AS A CAT "A" MAJOR REPAIR.