This is an odd statement:
...the owners of the Astro helicopter will need to install hydraulic assisted flight controls after 12 years regardless of the AD requirements.
I did not know there was an AD requiring installation of the hydraulic system.
What's odd about the statement? Robinson had a 12 year calendar time limit on non-hydraulic Astro blades. The non-hydraulic Astro blades are not made anymore and the ones currently in use are being phased out. The new blades will only work on Astro models with hydraulics installed. That's why they stated that Astro owners will have to install hydraulics after 12 years, regardless of the current AD.
The current AD cuts down to five year maximum the number of years remaining that Astro owners can run the non-hydraulic version rotor blades. Irregardless of this latest AD, Astro owners would have to eventually switch to the newer main rotor blades that only work on Astros that are equipped with hydraulics.