What was found
FUSLAGE FRAME TUBES FOUND BADLY CORRODED ON ANNUAL INSPECTION. WATER SOAKED INSULATION FOUND IN CONTACT WITH AFFECTED TUBES. SUBMITTER SUSPECTED WATER INGRESS FROM BADLY FITTING CABIN DOOR AND PV WINDOW SEALS. SUBMITTER RECOMMENDED THE UNDER FLOOR AREA BELOW THE CABIN DOOR AND PV WINDOW BE INSPECTED ON ALL AIRCRAFT OF A SIMILAR DESIGN TO THE PA23 FOR WATER INGRESS, AND CORROSION. DAMAGED AND WATER SOAKED INSULATION BLANKETS BE REPLACED. EXTRA WATER DRAINS BE INSTALLED TO LOWER FUSELAGE AREA IN ORDER TO MINIMIZE THE RISK OF WATER PUDDLES FORMING. (X)