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:
During aircraft structure fatigue tests, cracks were found in the wing lower skin stringers between ribs 7 and 10 on both wings. In order to prevent fatigue cracks in the wing lower skin stringers, which could result in fuel leakage and reduced structural integrity of the wing, the referred stringers must be reworked.
The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.