Summary
We are revising an earlier supplemental NPRM 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:
It has been found cases of corrosion at the regions of Wings-to- Fuselage attachments, Vertical Stabilizer to Fuselage attachments, Rib 1 Half-wing and Passenger Seat Tracks. Such corrosion may lead to subsequent cracking of the affected parts, compromising the aircraft structural integrity, which may in turn lead to structural failure and/or loss of some control surface.
The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.