Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all BAE Systems (Operations) Limited Model BAe 146 series airplanes. This proposal would require repetitive general visual inspections of the inside of the condenser regenerative air ducts, air cycle machine turbine outlet, and the jet pump ducts on each air conditioning pack to detect oil and/or oil breakdown products leaking from the engine(s) or auxiliary power unit (APU). This proposal would also require further inspections and replacement of any affected engine, APU, or component with a serviceable part, if necessary. This action is necessary to prevent impairment of the operational skills and abilities of the flight crew caused by oil or oil breakdown products in the cabin air, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.