Federal Aviation Administration March 8, 2005 – Federal Register Recent Federal Regulation Documents

The FAA proposes to adopt a new airworthiness directive (AD) for certain Airbus Model A320 series airplanes. This proposed AD would require post-maintenance bleeding of accumulated air from, or ground functional testing of, the ram air turbine (RAT) system; modifying and reidentifying the airborne ground check module of the RAT system; and replacing the RAT reducer assembly if applicable. This proposed AD is prompted by reports of unsuccessful in-flight RAT tests during which a deployed RAT failed to pressurize the blue hydraulic circuit of the RAT system. We are proposing this AD to prevent failure of the RAT during an in-flight emergency, which could lead to loss of hydraulic and electrical power and reduced controllability of the airplane.

This document proposes superseding an existing airworthiness directive (AD) that applies to Eurocopter France (Eurocopter) Model EC 155B, SA-365N and N1, AS-365N2, and AS 365 N3 helicopters. That AD currently requires inspecting the hydraulic brake hose (hose) for crazing, pinching, distortion, or leaks at the torque link hinge and replacing the hose, if necessary. That AD also requires inspecting the hose and the emergency flotation gear pipe to ensure adequate clearance, and adjusting the landing gear leg, if necessary. This action would require the same actions as the existing AD and would add a model to the applicability. This proposal is prompted by notification by the manufacturer and the European Authority that another affected model helicopter, the Model EC155B1, may have the same unsafe condition and should be added to the existing AD. The actions specified by the proposed AD are intended to prevent failure of a hose, resulting in failure of hydraulic pressure to the brakes on the affected landing gear wheel, and subsequent loss of control of the helicopter during a run-on landing.