Summary
We propose to adopt a new airworthiness directive (AD) for all Airbus Model A330-200, -200 Freighter, and -300 series airplanes; and all Airbus Model A340-200, -300, -500, and -600 series airplanes. This proposed AD was prompted by a report of blockage of Angle of Attack (AOA) probes during climb, leading to activation of the Alpha Protection (Alpha Prot) while the Mach number increased. This activation could cause a continuous nose-down pitch rate that cannot be stopped with backward sidestick input, even in the full backward position. For certain airplanes, this proposed AD would require replacing certain AOA sensors (probes) with certain new AOA sensors. For certain other airplanes, this proposed AD would also require inspections and functional heat testing of certain AOA sensors for discrepancies, and replacement if necessary. We are proposing this AD to prevent erroneous AOA information and Alpha Prot activation due to blocked AOA probes, which could result in a continuous nose-down command and consequent loss of control of the airplane.