Summary
We propose to adopt a new airworthiness directive (AD) for all Airbus Model A300 B2-1C, B2K-3C, B2-203, B4-2C, B4-103, and B4-203 airplanes. This proposed AD was prompted by analysis that in a specific failure case of the upper primary attachment of the trimmable horizontal stabilizer actuator (THSA); the THSA upper secondary attachment would engage because it could only withstand the loads for a limited period of time. This proposed AD would require installation of three secondary retention plates for the gimbal bearings on the THSA upper primary attachment. We are proposing this AD to prevent failure of the secondary load path, which could result in loss of control of the airplane.