Summary
We are revising an earlier NPRM for the products listed above. This action revises the earlier NPRM by expanding the scope. This 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: Several cases of corrosion and damage on the Down Drive Shafts (DDS), between the Down Drive Gear Box (DDGB) and the Input Gear Box (IPGB), on all 10 Flap Tracks (5 per wing), have been reported by AIRBUS Long Range Operators. Investigations have revealed that corrosion and wear due to absence of grease in the spline interfaces could cause [DDS] disconnection which could result in a free movable flap surface, potentially leading to aircraft asymmetry or even flap detachment. The unsafe condition could reduce the ability of the flightcrew to maintain the safe flight and landing of the airplane. The proposed AD wouldrequire actions to correct the unsafe condition on these products.