AD FAA-2016-9518

We are superseding Airworthiness Directive (AD) 2013-19-09 and AD 2014-25-51, which applied to all Airbus Model A318, A319, A320, and A321 series airplanes. AD 2013-19-09 required replacing Angle of Attack (AOA) sensor conic plates with AOA sensor flat plates. AD 2014-25-51 required revising the airplane flight manual (AFM) to advise the flightcrew of emergency procedures for abnormal Alpha Protection (Alpha Prot). This new AD requires replacing certain AOA sensors; and doing a detailed inspection and a functional heating test for discrepancies on certain AOA sensors, and replacing the affected AOA sensors. This AD was prompted by a report indicating that a Model A321 airplane encountered a blockage of two AOA probes during climb, leading to activation of the Alpha Prot while the Mach number increased. We are issuing this AD to address the unsafe condition on these products.