Summary
We propose to adopt a new airworthiness directive (AD) for certain Bombardier Model DHC-8-400, -401, and -402 airplanes. This proposed AD was prompted by reports of rudder bearings falling out of the fore rudder hinge bracket during assembly. This proposed AD would require a proof load test and detailed inspections; and installation of a new bearing, reaming, or repair of the bearing if necessary. We are proposing this AD to detect and correct improper bearing installation, which could result in abnormal wear and potential increased freeplay in the rudder system, and resultant airframe vibration, leading to compromise of the flutter margins of the airplane.