Summary
We propose to supersede Airworthiness Directive (AD) 2015-15- 10, for all Airbus Model A318, A319, A320, and A321 series airplanes. AD 2015-15-10 currently requires repetitive inspections of the trimmable horizontal stabilizer actuator (THSA) for damage, and replacement if necessary; and replacement of the THSA after reaching a certain life limit. Since we issued AD 2015-15-10, an additional life limit for the THSA has been established, based on flight cycles. In addition, the THSA manufacturer has issued service information which, when accomplished, increases the life limit of the THSA. This proposed AD would require repetitive detailed inspections of certain THSAs, and related investigative and corrective actions if necessary. We are proposing this AD to address the unsafe condition on these products.