Originally Posted by
wrench1
FYI: Just to add to the above. It actually depends on how the aircraft is operated, Part 91 or Part 135, whether the 12 year becomes "mandatory." Part 91 ops only requires the owner/operator to select an inspection program which at a minimum would consist of an Annual and replacement of any items listed in the approved Airworthiness Limitations section of the MM (i.e., Ch 3, 3.300). This would also include any engine related Airworthiness Limitation items, if applicable.
On the other hand, Part 135 ops are required to follow a manufacturer's recommended maintenance program, or FAA approved alternate, which at a minimum adds the R44 Chapter 2 requirements (i.e., O/Hs, etc.) to the "mandatory" list along with the Ch 3 requirements.
This is a great example of what I was saying about airworthiness of a Robinson being tied to the maintenance manual. At least here in the US, you have to do 100 hour inspections even if the aircraft is not being operated commercially. So, a private owner, under part 91 has to do 100 inspections in addition to the annual, assuming they fly more than 100 hours per year...