Summary
We propose to supersede Airworthiness Directive (AD) 2013-13- 16, which applies to all Airbus Model A330-200, A330-200 Freighter, A330-300 series airplanes, and all Airbus Model A340-200, -300, -500, and -600 series airplanes. AD 2013-13-16 currently requires repetitive inspections for discrepancies of the ball-screw assembly of the trimmable horizontal stabilizer actuator (THSA), repetitive greasing of the THSA ball-nut, and replacement of the THSA if necessary; and modification or replacement (as applicable) of the ball-nut assembly, which ends certain repetitive inspections. Since we issued AD 2013-13- 16, we have determined that a modification that automatically detects failure of the ball-screw assembly is necessary. This proposed AD would require an inspection, corrective actions if necessary, lubrication of the ball-nut, modification of the THSA, and removal of certain airplanes from the applicability. We are proposing this AD to address the unsafe condition on these products.