Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Airbus Model A300, A310, and A300-600 series airplanes. This proposal would require inspections to detect defects of the flanges of the bleed air ducts of the auxiliary power unit (APU), and to measure the material thickness of the flanges; and repair, replacement of the duct with a new or serviceable duct, or operation of the airplane with the bleed air system of the APU inoperative, if necessary. For certain airplanes, the proposal also would require an inspection to detect cracks of the flanges, and follow-on actions. This proposal is prompted by issuance of mandatory continued airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to prevent rupturing and cracking of the flanges of the bleed air ducts, which could damage the elevator control system and consequently reduce the controllability of the airplane.