What was found
DURING HEAVY MX CHECK-LH WING CRACK COMING OUT OF RIVET AT RIB 4A AS MARKED. COMPLIED WITH REMOVAL OF WING DOUBLER, REMOVAL OF WING CRACK,INSTALL OF DOUBLER, ASSOCIATED FASTENERS, AND FILLER MATERIAL REQUIRED PER ETD. COMPLIED WITH TOPCOAT. REF ETD2021-170-003349