Summary
This document proposes the adoption of a new airworthiness directive (AD) for Eurocopter Deutschland GmbH (ECD) Model EC135 P1 and EC135 T1 helicopters. This proposal would require inspecting the hydraulic line shielding hose (hose), replacing any unairworthy hose with an airworthy hose, and installing a nylon cable tie. This proposal is prompted by the tail rotor drive shaft Thomas coupling contacting and chafing the hose that shields the fenestron tail rotor hydraulic lines. The actions specified by the proposed AD are intended to prevent damage to the hose, leaking of accumulated hydraulic fluid to an area with an ignition source, inflight fire, and subsequent loss of control of the helicopter.