Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Airbus Model A330-202, -203, -223, -243, and -300 series airplanes. This proposal would require modification of the control box of the auxiliary power unit (APU). This action is necessary to prevent uncommanded in-flight shutdown of the APU, which could result in loss of critical electrical systems when the airplane is operated in emergency electrical configuration, and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.