Airworthiness Directives; Airbus Airplanes

We are adopting a new airworthiness directive (AD) for all Airbus Model A300 series airplanes; Model A300 B4-600, B4-600R, and F4- 600R series airplanes, and A300 C4-605R Variant F airplanes (collectively called Model A300-600 series airplanes); and Model A310 series airplanes. This AD was prompted by reports of cracked aluminum support struts of the trimmable horizontal stabilizer (THS) caused by stress corrosion. This AD requires inspections to identify the part number of each support strut, repetitive inspections for cracking of the THS support strut ends, installation of reinforcing clamps on strut ends, and replacement of support struts, if necessary. We are issuing this AD to detect and correct cracked THS support struts, which could lead to the rupture of all four support struts making the remaining structure unable to carry limit loads, which could result in loss of the THS and reduced control of the airplane.