Airworthiness Directives; Airbus Airplanes

We are adopting a new airworthiness directive (AD) for all Airbus Model A318, A319, A320, and A321 series airplanes. This AD was prompted by reports of spoiler and elevator computer (SEC) latent failures; an undetected loss of a SEC in flight will result in loss in redundancy for elevator control. This AD requires revising the After Start Normal Procedures section of the airplane flight manual (AFM) to provide procedures that will address this loss of redundancy. We are issuing this AD to ensure that the flightcrew has procedures to address loss of redundancy of SEC 1 and SEC 2. A SEC failure, in conjunction with a loss of trimmable horizontal stabilizer (THS) electrical control due to jamming or rupture, could result in failure of an elevator and aileron computer, and consequent loss of elevator control and reduced control of the airplane.