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:
This Airworthiness Directive (AD) is prompted due to the discovery of corrosion at the bonding strap connections on the left and right lower longerons between fuselage frames 1 and 1A. The possibility of corrosion is increased because of the high electrical current flow between the tinned copper terminal lug of the bonding strap and the aluminum longeron. Such a condition, if left uncorrected, could lead to failure of the longeron and will prejudice the structural integrity of the aircraft.
The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.