Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain EMBRAER Model EMB-145 and -135 series airplanes. This proposed AD would require replacing the horizontal stabilizer control unit (HSCU) with a modified and reidentified or new, improved HSCU. For certain airplanes, this proposed AD would also require related concurrent actions as necessary. This proposed AD is prompted by reports of loss of the pitch trim system due to a simultaneous failure of both channels of the HSCU. We are proposing this AD to prevent loss of pitch trim and reduced controllability of the airplane.