Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede Airworthiness Directive (AD) 2004-16- 01, that applies to certain Airbus Model A330-200 and -300, and Model A340-200 and -300, series airplanes. AD 2004-16-01 currently requires repetitive inspections for cracking of the chromed area of the left and right piston rods for the main landing gear (MLG) retraction actuators, and related investigative and corrective actions if necessary. Since we issued AD 2004-16-01, we have determined that the presence of water in the internal volume of the piston rod can consequently lead to propagation of longitudinal cracking in the body of the piston rod. We have also determined through sampling that certain retraction actuator piston rods of the MLG need to be replaced. This proposed AD would require repetitive draining of any fluid from the retraction actuator piston rod internal volume and sealing of the vent hole; repetitive ultrasonic inspections of the upper end of the piston rods, and corrective actions if necessary; a one-time ultrasonic inspection (longitudinal and circumferential) of the full-length of the piston rod, and corrective actions if necessary; and a terminating modification of the left-hand and right-hand MLG retraction actuators. We are proposing this AD to prevent cracking of the piston rods for the MLG retraction actuators, which could result in rupture of a piston rod, non-damped extension of the MLG, high loads on the fully extended MLG, and consequent reduced structural integrity of the MLG.