Summary
We propose to supersede Airworthiness Directive (AD) 2012-08- 11 for certain Bombardier, Inc. Model DHC-8-400 series airplanes. AD 2012-08-11 currently requires repetitive detailed inspections for defects and damage of the retract port flexible hoses on the left and right Main Landing Gear (MLG) retraction actuator, and replacement of the flexible hoses if necessary. Since we issued AD 2012-08-11, we determined that the orientation of the retraction actuator ports must be revised to address the identified unsafe condition. This proposed AD would continue to require the actions required by AD 2012-08-11, and would require reorientation of the retraction actuator of the MLG, which would terminate the repetitive inspections. This proposed AD would also remove airplanes from the applicability. We are proposing this AD to prevent hydraulic fluid leakage in the event of a damaged retract port flexible hose failure; this condition could lead to an undamped extension of the MLG and could result in MLG structural failure, leading to an unsafe, asymmetric landing configuration.