Federal Aviation Administration May 2, 2013 – Federal Register Recent Federal Regulation Documents

We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model 727 series airplanes. This proposed AD was prompted by a report of cracking in the left-side chord of the fin closure rib on the vertical stabilizer. This proposed AD would require repetitive inspections of the left and right side chords of the fin closure rib for cracking and corrosion, and related investigative and corrective actions if necessary. We are proposing this AD to detect and correct cracking and corrosion in the left and right side chords of the fin closure rib, which could lead to widespread cracking in the chords that might weaken the fin closure rib structure and result in loss of airplane control due to lack of horizontal stabilizer support.

We propose to supersede an existing airworthiness directive (AD) that applies to all Airbus Model A318, A319, A320, and A321 series airplanes. The existing AD currently requires revising the airplane flight manual (AFM) to advise the flightcrew of emergency procedures for addressing angle of attack (AoA) sensor blockage. The existing AD also provides for optional terminating action for the AFM revision, which involves replacing AoA sensor conic plates with AoA sensor flat plates. Since we issued that AD, we have determined that the replacement of AoA sensor conic plates is necessary to address the identified unsafe condition. This proposed AD would mandate the installation of AoA sensor flat plates and removal of the AFM revision. We are proposing this AD to prevent reduced control of the airplane.