Summary
We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:
It has been found that the implementation of the Inertial Reference Units (IRU) on the ERJ-170 [and ERJ-190] may lead, in certain degraded modes, to an erroneous Flight Path Angle (FPA) indication on both Primary Flight Displays, with no alert to the flight crew. On the ERJ-170 [and ERJ-190], FPA is considered as important as pitch and bank angle for piloting purposes.
The unsafe condition is reduced ability of the flightcrew to control the flight path of the airplane. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.