Summary
We are revising an earlier proposed airworthiness directive (AD) for all Airbus Model A318, A319, A320, and A321 series airplanes. That supplemental notice of proposed rulemaking (SNPRM) proposed an inspection to determine if certain angle of attack (AOA) probes are installed, and replacement of any affected AOA probe. That SNPRM was prompted by reports of oil residue between the stator and the rotor parts of the position resolvers of the AOA vane, which was a result of incorrect removal of the machining oil during the manufacturing process of the AOA resolvers. This action revises that SNPRM by clarifying the affected parts. We are proposing this AD to prevent erroneous AOA information and consequent delayed or non-activation of the AOA protection systems which, during flight at a high angle of attack, could result in reduced control of the airplane. Since these actions impose an additional burden over that proposed in the SNPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.