What was found
*LH WING TOP SKIN PANEL 540AT HAS FRETTING CORROSION ON LANDING. (C-CHECK - RO 6/19/21) / REMOVED CORROSION FROM LH WING TOP PANE 540AT LANDING REF CRJ 200 SRM 51-21-06. FOUND TO BE OUT OF LIMITS REF CRJ 200 SRM 57-21-31. MEASURED THICKNESS .199. ORIGINAL THICKNESS .200 REF DRAWING 601R10042 REV-U. MATERAL LOSS .001 MAX ALLOWED ZERO. COMPLIED WITH REO 601R-57-21-3462 REV-- DATED 2021-04-26. AND RESTORED FINISH REF CRJ-200 SRM 51-25-06