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:
The Chromic Acid Anodising (CAA) Lead Fleet Program was established in 1989 to observe corrosion/debonding behaviour of CAA- treated panels. CAA lead fleet includes the inspection of lap joints, circumferential joints, stringers and doublers on selected aircraft. The findings in combination with analytical corrosion investigations have been analysed by the TC (type certificate) holder and an appropriate inspection program for debonding has been developed. This airworthiness directive requires inspection of the concerned areas to detect any corrosion and/or debonding which could affect the structural integrity. * * *
The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.