Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-90-30 series airplanes. This proposal would require modification of the right and left main landing gear (MLG) hydraulic damper assemblies or replacement of the MLG hydraulic damper assemblies with modified and reidentified hydraulic damper assemblies. This proposal is prompted by reports indicating that, during overhauls, the MLG hydraulic dampers assemblies failed or had damaged spring retainers due to insufficient material thickness of the spring retainers. The actions specified by the proposed AD are intended to prevent failure of the hydraulic damper assemblies of the MLG, which could result in vibration damage and collapse of the MLG.