Originally Posted by
aa777888
I can only answer from a US perspective, i.e. not sure how things are mandated in other countries.
Where it gets a little subtle is that while Robinson recommends a 12 year inspection on those remaining components the FAA does not mandate it. So you can legally continue to run the helicopter in the US past the 12 year mark without doing a Robinson recommended and described (Chapter 2, Section 2.600) 12 year inspection. If you do decide to do a 12 year inspection (not overhaul, i.e. you are not throwing away the life limited components listed on the type certificate early) it should cost you around $40K USD. People do it both ways all the time.So under the right conditions you can allow the engine to go on-condition until 2200, although it may be that you start replacing seals and whatnot, and if the compression is starting to drop any A&P is going to tell you to throw in the towel and overhaul it.
I won't argue with this interpretation, but another one I have been told by a couple different maintenance organizations is that the 12 year inspection is mandatory because of the wording in the maintenance manual. Again, I won't argue with what you said it sounds pretty authoritative... There are some components called out on the list like the MR transmission which is probably a good idea to inspect after 12 years ( especially in the coastal areas like greater Boston ). Problem being that I believe that can only be done at the factory,. And you might not like their answer, but once you send it to them I doubt you can ignore their decision.
I know there is a guy down south that does the full inspection, but I think he gets closer to $70K for the job. Every private owner I fly with that has hit this ( 4 I think ) have just decided to do the overhaul. If you know about this when you buy the aircraft, you can buy a used machine with hours on it so you aren't hitting 12 years with lots of component time left. But of course a large segment of private owners like to buy new machines...
As for the engine, a school I taught at ran their R22 engines past TBO, but did oil analysis... And they would all start making metal about 200 hours past TBO... It really didn't make sense to me. I don't know anyone who runs the R44 engine past TBO so I have no idea how that engine behaves. However, given that we are talking about private owners here, I don't think the additional risk of an in flight engine failure is worth the slight decrease in operating expenses... Private owners are seldom as experienced and current on autorotations, so you end up risking the entire hull, not to mention lives...
To some degree I see a difference between R22 and R44 owners... Seems like more R22 owners are struggling with operating costs... The R44 owners seen to be more composed of wealthier individuals that can afford the additional cost of the overhaul. Which, let's face it, is still pretty darn cheap compared to what it costs if you upgrade to a turbine machine...