AD FAA-2007-28094

The FAA is superseding an existing airworthiness directive (AD), which applies to all EMBRAER Model ERJ 170-100 LR, -100 STD, -100 SE, and -100 SU airplanes. That AD currently requires repetitively replacing the low-stage check valve and associated seals of the right- hand engine bleed system. This new AD adds new airplanes to that existing requirement. For all airplanes, this AD also requires repetitively replacing the low-stage check valve and associated seals of the left-hand engine bleed system with a new check valve and new seals. This AD results from a report that an engine shut down during flight due to the failure of the low-stage check valve to close. We are issuing this AD to prevent failure of the low-stage check valve, which could result in an engine shutting down during flight.