Airworthiness Directives; Boeing Model 727 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to all Boeing Model 727 series airplanes, that requires a review of maintenance records or a one-time test to determine if elevator hinge support ribs on the trailing edge of the horizontal stabilizer are made from a certain material, and follow-on repetitive inspections for corrosion or cracking of the elevator hinge support ribs, if necessary. For airplanes with the affected ribs installed, this AD eventually requires replacement of all affected ribs with new, improved ribs. This action is necessary to prevent cracking of the elevator hinge support ribs, which could lead to vibration of the airframe during flight and consequent damage to the elevator and horizontal stabilizer, potentially resulting in loss of controllability of the airplane. This action is intended to address the identified unsafe condition.