Summary
We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:
There have been failures of the harness assembly (power feeder wires) connecting the Air-Driven Generator (ADG) to the aeroplane electrical system, in the area close to the ADG cannon plug. Several electrical wires were found cut as a combined result of corrosion and bending stress from the harness mounting to the ADG. The ADG electrical wires are insulated with a silver-plating for corrosion protection. It has been determined that the silver-plating of wire strands in the area of tight bend is highly susceptible to breakdown. The plating layer may crack as a result of mechanical stress, and consequently lead to the onset of corrosion onall, or a majority, of the wire strands. In the event of a damaged harness assembly, the ADG may not be able to provide emergency electrical power to the aeroplane. * * *
The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.