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:
One Long Range operator experienced a failure of one spoiler servo-control, associated with surface deflection in flight and hydraulic leak. On ground, this servo-control Part Number (P/N) MZ4306000-02X was found with the maintenance cover broken. Investigations showed that the rupture of the maintenance cover was due to pressure pulse fatigue. * * * The rupture of the maintenance cover in flight may result in the deflection of the associated spoiler surface up to the null- hinge position (loss of the hydraulic locking). It may also result in the loss of the associated hydraulic system (external leakage). In the worst case, the three hydraulic systems may be affected, which constitutes an unsafe condition.
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Loss of the three hydraulic systems could result in reduced controllability of the airplane. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.