Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Airbus Model A318, A319, A320, and A321 series airplanes. This proposed AD would require replacing the water drain valves in the forward and aft cargo doors with new valves. This proposed AD is prompted by a report indicating that, during a test of the fire extinguishing system, air leakage through the water drain valves in the forward and aft cargo doors reduced the concentration of fire extinguishing agent to below the level required to suppress a fire. We are proposing this AD to prevent air leakage through the water drain valves, which, in the event of a fire in the forward or aft cargo compartment, could result in an insufficient concentration of fire extinguishing agent and consequent inability of the fire extinguishing system to suppress the fire.