What was found
MAJOR: WHILE AIRCRAFT WAS IN FOR HEAVY CHECK. EXTERNAL DOUBLER LOCATED FR 22, STGR 13L-15L REQUIRES EVALUATION. COMPLIED WITH ETD2021-170-001535. REMOVED DOUBLER, LOCATED AND DRILLED NEW DOUBLER AND FILLER. INSTALLED NEW DOUBLER AND FILLER, IAW ETD2021-170-001535. AIRCRAFT IS STILL CURRENTLY OUT OF SERVICE FOR HEAVY CHECK COMPLETION.