As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING HEAVY MAINTENANCE IT WAS DISCOVERED ON THE LHS WING FWD SPAR AT WS 490.0 SPLICE JOINT. 4 CRACKED LOCKBOLT COLLARS PN BACC30BK5 WERE FOUND. REQUEST HAS BEEN SENT TO BOMBARDIER TO REPLACE LOCKBOLTS AND COLLARS WITH HILOCK SUBSTITUTES. DETAILED VISUAL INSPECTION CARRIED OUT ON ALL THERE COLLARS WITH NO FAULTS FOUND,