What was found
WHILE CLOSING ACFT MAIN ENTRY DOOR, NOTED DOOR WOULD NOT PROPERLY CLOSE AND LOCK. DURING INVESTIGATION AND T/S OF MAIN ENTRY DOOR, JACKSHAFT ASSY PN 159AM10057-3 WAS FOUND TO HAVE A FRACTURE CRACK RUNNING THE FULL LENGTH. OLD JACKSHAFT WAS REMOVED AND REPLACED WITH P/N 159AM10057-5. AFTER FURTHER RESEARCH, ASC NR 146 ADDRESSES REWORK OF AIRSTAIR DOOR. THIS ASC PROVIDES INSTRUCTION FOR REMOVAL AND REPLACEMENT OF JACKSHAFT AND ADDITIONAL COMPONENTS REQUIRED FOR REPLACEMENT OF NEW JACKSHAFT P/N. REMOVAL AND REPLACEMENT OF THE JACKSHAFT BY ITSELF COULD CAUSE FURTHER DAMAGE WITHOUT CHANGING AL REQUIRED COMPONENTS AS CALLED OUT IN ASC 146. CAUSE OF FAILURE IS UNKNOWN.