R44 12 Year Inspection
Join Date: Sep 2000
Location: states
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Mandatory
No, under U S part 91, not for hire ( part 91 for hire is different), you do not need 100 hr inspections to be legal. You need an annual once every calendar year. Doesn't matter what the maintenance manual says unless the 100 hr requirement is in ATA chap. 4 as an airworthiness limitation ( and it isn't). The Cessna 150 manual has a 100 hr as well and you dont need to do that under 91 either. Helicopter or airplane is no different. You had better be able to tell the FISDO wonks what inspection you are using and why, as a lot of them are misinformed. CFR 91.409 is pretty clear. As I stated above the only part of almost all maintenance manuals in the US that is FAA approved is chap 4.
That document clearly states that any method or technique that is in a manufacturers document that is called out in the tcds, must be supported by regulation. The regulation does not say you have to do 100 hr inspections if you are not flying for hire under part 91. I can't tell from your post if you agree or disagree.
To clarify for you:
Part 91 private ops: Annual inspection; Airworthiness Limitations life-limited part replacement.
Part 91 for hire: Annual inspection; Airworthiness Limitations life-limited part replacement; current 100hr (or Annual in previous 100hrs) inspection only when operating as a "for-hire" flight. If you make one "for-hire" flight in a year then only one 100hr inspection is needed in that year--unless your "for-hire" flight is within the subsequent 100hrs of your last Annual. There is no 100hr requirement for a Part 91 private ops flight.
Join Date: Nov 2007
Location: Massachusetts
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I believe you mis-read my post as your statement is not correct.
To clarify for you:
Part 91 private ops: Annual inspection; Airworthiness Limitations life-limited part replacement.
Part 91 for hire: Annual inspection; Airworthiness Limitations life-limited part replacement; current 100hr (or Annual in previous 100hrs) inspection only when operating as a "for-hire" flight. If you make one "for-hire" flight in a year then only one 100hr inspection is needed in that year--unless your "for-hire" flight is within the subsequent 100hrs of your last Annual. There is no 100hr requirement for a Part 91 private ops flight.
To clarify for you:
Part 91 private ops: Annual inspection; Airworthiness Limitations life-limited part replacement.
Part 91 for hire: Annual inspection; Airworthiness Limitations life-limited part replacement; current 100hr (or Annual in previous 100hrs) inspection only when operating as a "for-hire" flight. If you make one "for-hire" flight in a year then only one 100hr inspection is needed in that year--unless your "for-hire" flight is within the subsequent 100hrs of your last Annual. There is no 100hr requirement for a Part 91 private ops flight.
So, for 30+ years I've been told by various maintenance organizations that the MM ends up requiring 100 hours in Robinson helicopters, regardless of whether they are commercial use or not. I did a bunch of research and must admit that it appears you are correct and that I was wrong. Sorry for the bad information!
Maintennce shops are in business to provide maintenance. Of course they will imply 100 hour inspections are truly mandatory because the maintenance manual says so. Robinson and perhaps others say that because they can see the liability issues with some joker flying his toy 400 hours in a year and doing only one inspection. Same thing with service bulletins . A manufacturer can call it mandatory because in their eyes it is, even though regulation doesn't say that unless it is in your ops specs. Think about it. If a manufacturer could actually make something mandatory, they would in effect be legislating. In the US and other places that is not allowed. That is why the Airwortiness Limitations schedule in the maintenance manual is the only FAA approved part of the book. They have made it into regulation by doing so. The type certificate backs that up, as does the US Code of Federal Regulations.
FWIW: While you bring up a valid point on a 100 hour inspection, your definition of an owner who doesn't comply with a 100hr is a bit misinformed. There are a number of private helicopters, to include various turbine models, that operate over 100s of hours with only an Annual performed. However, the reason isn't because the owner is a putz or lazy, rather it could be for several reasons. Perhaps the aircraft operates in a remote or isolated area where the nearest mechanic or maintenance facility might be several days away. So from a logistics and cost standpoint, staging the aircraft or flying a mechanic in to perform a non-required inspection every other month vs once a year doesn't quite make sense. Or, in a more urban environment the owner may maintain his aircraft to a level where a 100hr offers no additional oversight. Having been involved in these types of ops and owners, I believe your definition is not reflective of actual operations, at least not in the US.
When you say it doesn't make sense I have to ask what you really mean by that. I can only assume you mean economic sense, because honestly I can't think of another reason to not get a mechanic out to the helicopter. Nobody ever said private ownership of a helicopter was inexpensive.
I am truly shocked that anyone wants to skip or stretch maintenance checks. Having owned and run many helicopters ( over 30 now ) I can assure you the best and cheapest maintenance is preventative maintenance. It is way way cheaper in the long run to over maintain a machine, eg a slight vibration from the main rotor for instance can lead to premature wear on other components, let alone the safety and piece of mind. There is no excuse that the machine is in a remote location or it is not cost effective.
My comment was to your blanket statement that any owner who doesn't perform a 100 hour is lazy or a cheapskate and in context to whether a 100hr is required or not. I too have 40 years in the mx business, however, my experiences differ to yours. I won't deny there are owners out there as you have mentioned, which could include several 135 operators I know as well as well. However, I was in a position to select which owners I assisted so in all honesty I would never work with people who operated as you describe. And this included both my airplane and helicopter customers. So, in my opinion, your statement is mis-informed or inaccurate of all owners simply because they do not perform a non-required 100 hour inspection. In my experience, it's not what gets done on an aircraft, it's the who and how that aircraft is maintained. Lastly, in the last 30 years or so, I can state without hesitation that "economics" has never been a deciding factor in any decision made by any owner I assist. But if you believe simply complying with more inspections makes an aircraft safer then I respect your belief.
My comment was to your blanket statement that any owner who doesn't perform a 100 hour is lazy or a cheapskate and in context to whether a 100hr is required or not. I too have 40 years in the mx business, however, my experiences differ to yours. I won't deny there are owners out there as you have mentioned, which could include several 135 operators I know as well as well. However, I was in a position to select which owners I assisted so in all honesty I would never work with people who operated as you describe. And this included both my airplane and helicopter customers. So, in my opinion, your statement is mis-informed or inaccurate of all owners simply because they do not perform a non-required 100 hour inspection. In my experience, it's not what gets done on an aircraft, it's the who and how that aircraft is maintained. Lastly, in the last 30 years or so, I can state without hesitation that "economics" has never been a deciding factor in any decision made by any owner I assist. But if you believe simply complying with more inspections makes an aircraft safer then I respect your belief.
if economics was not the root cause of why the maintenance interval is being stretched, then what was the reason? It actually all boils down to money. Convenience, remoteness even weather to the extent that it can be forecast are not valid reasons in my view, but rather are excuses for delaying. We all drone on about safety and how it has to be elevated above the need to leave the ground ( no pun intended), so you have to walk the talk. Of course one can do a poor job of inspecting or even create an issue one fails to see in the course of doing work but that is never the intention and your corallary implication that it would not be true that the more eyes on something the greater the liklihood something will be seen, is something I reject.
We can debate maintenance philosophy all week but in my experience, in many instances, I didn't know the customer or their machine until I did an inspection and didn't have the luxury or conscience that allowed me to walk away ( although there were a couple of situations so heinous that it was the only choice). I actually was the person who frequently would tell an owner " look, you don't have to bust your butt getting here before you hit 100 hours". As I said above, there is nothing magic about that number and was often met with surprise when it was explained they really didn't violate any regulations if they never did the 100 hr inspection. I stopped doing that because I saw it get abused because they really were cheap or lazy. Yes, most of the time more inspections would be my choice no matter who does them because in my experience there are more competant mechanics than incompetant. Your mileage may vary and past performance is no predictor of future returns. It's like the dilemma of the landing light. Do I test it on preflight if I know it worked last night or will it be the lst time it lights and doesnt burn out, thereby leaving me with no landing light when I need it. You can disagree all day long but there is no real reason for testing it if it worked.....or is there? Things do take a turn for the broken at the most unexpected times.
It's this statement that I think reflects the major difference in our collective experiences. As I mentioned, I was in a position to fully review the owner and aircraft prior to any inspection or work. I had a Part 135/145 day job that provided a good income and basically half a year off. Back in the first 5 years I provided ad hoc mx services, I would always run into similar situations as you describe. However, once I established myself and shifted to more owner-assisted mx and more private helicopters, I dropped the ad hoc side and went owner-exclusive till I "retired" 5 years ago. In the 30+ years I assisted owners in this way, I only walked away from one person which unfortunately was not due to him becoming lazy or a cheapskate, rather he had some mental issues that could not be controlled. So it can really depend on the individual and situation on how mx is done or scheduled. But I can understand your view based on your stated experiences as I've lived them too. Best of luck.
Join Date: Apr 2010
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From a low time owner and pilot perspective, I think the 100 hour inspections are worth doing. Even though the problems are typically minor, we always find a few here and there. And when your A&P has infinitely more experience at recognizing broken stuff than you do, hell, it's worth having them just sit in your running helicopter every once in a while. They can more easily recognize sounds and vibrations that you might not. For example: that can be the difference between your fan needing balancing and a bunch of cracked engine air shrouds.