As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT WING REAR SPAR WS 48.30 BATT RIB WEB HAS CORROSION AROUND UPPER LIGHTING HOLE FWD AND AFT SIDES AND AT THE BASE WHERE IT ATTACHES TO LOWER AFT ANGLE. ***AIRCRAFT REMOVED FROM SERVICE*** REMOVED CORROSION ON LH WING REAR SPAR WS 48-30 BATT RIB WEB, ORIGINAL THICKNESS 0.050", MATERIAL LOSS 0.004". WITHIN LIMITS REF ASAP AWAC EA# CRJ257-01599 REV A DATED 4/15/2021.