Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede Airworthiness Directive (AD) 2011-13- 11 and AD 2013-16-09, for all Airbus Model A318, A319, A320, and A321 series airplanes. AD 2011-13-11 currently requires an amendment of the airplane flight manual (AFM), repetitive checks of specific centralized fault display system (CFDS) messages, an inspection of the opening sequence of the main landing gear (MLG) door actuator for discrepancies if certain messages are found, and corrective actions if necessary. AD 2013-16-09 currently requires an inspection to determine airplane configuration and part numbers of the landing gear control interface unit and MLG door actuators; and, for affected airplanes, repetitive inspections of the opening sequence of the MLG door actuator, and replacement of the MLG door actuator if necessary; and provides optional terminating action for the repetitive inspections. Since we issued AD 2011-13-11 and AD 2013-16-09, we have determined that the interval of the MLG door opening sequence inspection must be reduced. This proposed AD would reduce the interval of the MLG door opening sequence inspection. This proposed AD would also require replacing or modifying certain MLG door actuators. We are proposing this AD to detect and correct deterioration of the damping ring and associated retaining ring of the MLG door actuator, which can sufficiently increase the friction inside the actuator to restrict opening of the MLG door by gravity, during operation of the landing gear alternate (free-fall) extension system. This condition could prevent the full extension and/or down-locking of the MLG, possibly resulting in MLG collapse during landing and consequent damage to the airplane and injury to occupants.