Summary
We propose to supersede Airworthiness Directive (AD) 2013-19- 09 and AD 2014-25-51, for all Airbus Model A318, A319, A320, and A321 series airplanes. AD 2013-19-09 currently requires replacing Angle of Attack (AOA) sensor conic plates with AOA sensor flat plates. AD 2014- 25-51 currently requires revising the airplane flight manual (AFM) to advise the flightcrew of emergency procedures for abnormal Alpha Protection (Alpha Prot). Since we issued AD 2013-19-09 and AD 2014-25- 51, we have received a report indicating that certain AOA sensors appear to have a greater susceptibility to adverse environmental conditions. This proposed AD would require 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. We are proposing this AD to address the unsafe condition on these products.