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:
It has been found that some of the above mentioned MLG special bolts can be defective. The problem is only applicable to specific bolts with serial numbers that start with the letters AT or have the supplier code AT. Investigations revealed that there is a possibility for hydrogen embrittlement which occurs during the manufacture process.
Components in this condition can decrease the specific fatigue life and could lead to MLG collapse during operation with consequent loss of airplane control.
The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.