Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain McDonnell Douglas airplanes. This proposed AD would require a general visual inspection for damage to the Firex discharge pipes and wye assembly of the number 2 engine fire extinguishing system; and corrective and other specified actions, as applicable. This proposed AD is prompted by reports of freezing damage to the Firex discharge pipes and wye assembly of the number 2 engine, and one report of a level 1 ENG FIRE AGENT LO alert during flight. We are proposing this AD to prevent accumulation of water in the discharge pipes and possible consequent freezing damage to the discharge pipes and wye assembly, which could lead to failure of the fire extinguishing system during a fire in the number 2 engine.