Airworthiness Directives; Airbus Model A330-200 and A330-300 Series Airplanes, and Model A340-200, A340-300, A340-500, and A340-600 Series Airplanes

요약

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as: Investigation conducted by Thales on probes revealed oil residue between the stator and the rotor parts of the AoA [angle of attack] vane position resolvers. This oil residue was due to incorrect cleaning of the machining oil during the manufacturing process of the AoA resolvers. At low temperatures, this oil residue becomes viscous (typically in cruise) causing lag of AoA vane movement. Such condition could lead to discrepant AoA measurement. If not corrected, and if two or three AoA probes were simultaneously affected and provided wrong indications of the AoA to a similar extent, it could lead to a late activation of the angle of attack protection, which in combination with light at high angle of attack would constitute an unsafe condition. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.