Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Airbus Model A300-600 airplanes. This proposed AD would require an inspection for evidence of chafing between the hydraulic flexible hose and the ram air turbine (RAT) hub, and related investigative and corrective actions if necessary. This proposed AD is prompted by reports of holes in the RAT hub cover. We are proposing this AD to prevent a hole in the RAT hub cover. A hole in the RAT hub cover could allow water to enter the RAT governing mechanism, freeze during flight, and jam the governing mechanism. In addition, the metal particles that result from chafing between the hydraulic flexible hose and the RAT could mix with the lubricant grease and degrade the governing mechanism. In an emergency, a jammed or degraded RAT could result in its failure to deploy, loss of hydraulic pressure or electrical power to the airplane, and consequent reduced controllability of the airplane.