What was found
CESSNA 340A, WITH ROBERTSON STOL KIT, NOW OWNED BY SIERRA INDUSTRIES, STC SA474NW. ALUMINUM FLAP ACTUATOR TORQUE TUBE FOUND NEARLY SEVERED BY A WORN PRESSURIZATION SEAL. DEFECT WAS ONLY FOUND BECAUSE OWNER REPORTED POOR PRESSURIZATION DIFFERENTIAL AND ALL FUSELAGE LEAKS WERE BEING CORRECTED. IT IS NOT VISIBLE WITHOUT DISASSEMBLY OF PARTS. FAILURE OF PART WOULD CERTAINLY RESULT IN ASYMMETRICAL FLAPS. SUBMITTER STATED TORQUE TUBE SHOULD HAVE A STAINLESS STEEL SLEEVE AS THE SOFT ALUMINUM TUBE WAS CUT BY STEEL IN THE SEAL.