Summary
We propose to supersede an existing airworthiness directive (AD) that applies to certain Embraer S.A. Model ERJ 170 and ERJ 190 airplanes. The existing AD currently requires, for certain airplanes, repetitively replacing the low-stage check valve and associated seals of the right hand (RH) engine's engine bleed system with a new check valve and new seals, replacing the low pressure check valves (LPCV), and revising the maintenance program. For certain other airplanes, the existing AD requires replacing a certain low-stage check valve with an improved low-stage check valve. Since we issued that AD, we have received reports of uncommanded engine shutdowns on both Model ERJ 170 and ERJ 190 airplanes due to excessive wear and failure of LPCVs having certain part numbers. This proposed AD would also, for certain airplanes, require replacing certain LPCVs of the left-hand (LH) and RH engines, which would be an option for other airplanes. We are proposing this AD to prevent the possibility of a dual engine in-flight shutdown due to LPCV failure.