I looked at a Cessna 172 that is in owner maintenance and I am curious on the paperwork behind one "Mod" that was completed. Apparently there was a group of owners who all put their 172s into owner-maintenance, got together as a group and purchased one Sportsman STOL kit which they then used to copy, create and install kits in multiple planes (with only one set of STC paperwork). From my preliminary viewing the work appears to be well done (owner had multiple homebuilt planes previously and the group included at least one AME) but I am unsure on the legality over what they did. I am mostly interested in the "airworthiness" perspective not the commercial/ethics of copying someones work without paying for it.
The one AME I spoke was of the opinion that what was done was not technically legal but would be fine as long as nothing happened (i.e. insurance/TC investigation after an incident) similar to several O-300s in the same area with High compression pistons installed without paperwork. If the work was well done with appropriate materials are there any issues that I should be aware of?
Thanks in advance for the input.
The TC policy on this (#1212867, Rev 3, of July 01, 2008, reads in part:
And, from the CARS:2.3 The provisions of the CAR’s and related standards allow the owner(s) of a small aeroplane to perform the maintenance on their aircraft, effect modifications and repairs without Transport Canada approval and install uncertified parts; the provisions also authorize the owner(s) to sign the maintenance release for all maintenance performed on their aircraft.
So, although the OM category was not really intended to be a free for all for modifications, (I was present at all of the CARAC meetings for this new rule back in the day), the rules have been written to allow mods to squeak through. In particular, because the possibilities for approval of the mods on OM aircraft are now limited. As a DAR, I cannot issue a serialized STC to an OM airplane (TC rules, and on one every asks!).571.06 (1) Except as provided in subsection (5) and in the case of aircraft that are operated under a special certificate of airworthiness in the owner-maintenance classification, a person who signs a maintenance release in respect of a major repair or major modification on an aeronautical product shall ensure that the major repair or major modification conforms to the requirements of the relevant technical data
So it really becomes up to you to make the determination if the work accomplished on the plane meets your standards of airworthiness! The work might be excellently done, and you'd be proud to own the plane. OM does not mean the plane is poor, it just means that it is possible that an AME/AMO has not been involved in work accomplished. It is fair that you would ask to see detailed work reports for mods accomplished, and evidence that the work was actually done in accordance with installation instructions which you accept as appropriate. Though an AME will not sign a maintenance release for the plane, you can still ask an AME to perform a pre purchase inspection against the certified standards for the plane, and see where the differences (if any) are. The fact that a plane is in the OM category is not reason that it need have poorer documentation of the work accomplished! It's just who signed for it!
I'm a proponent of OM, having one plane in that category, and planning to put another in before too long. And, I'll still use appropriate data for modifications, and keep good records.
One cautionary note, and that is that the person signing out the work might overlook the standard STC mod requirement (on the bottom of every certificate)
Once you start mixing STC mods together, this can have real implications, and must be considered. Some STC mods do not mix well with others, and in some cases, this can include STOL kits. I'm a big fan of STOL kits, but they must be considered in context on the plane.Prior to incorporating this modification, the installer shall establish that the interrelationship between this change and any other modification(s) incorporated will not adversely affect the airworthiness of the modified product.
I know that I have not exactly answered your question, I'm not certain that there is a certain answer. On the other hand, if the work is well done, and never contributes to a defect or problem, probably no one is worried about it! Buyer beware, and if you want to own OM, you'd best either be well acquainted with the requirements, or employ an AME who is. You can sign for his/her work with an OM plane.
You can't just slap STC paperwork on top of homemade parts as then those parts would be classified as suspected unapproved parts, they were not made by the certificate holder or anyone else approved.
I thought the intention of OM was for people with aircraft that couldn't be supported anymore and not cheapo's who are constantly cutting corners.
I wonder how many people remove the warning stickers from the plane after they go OM?
- Top Poster
- Posts: 7628
- Joined: Tue Jan 18, 2011 4:47 pm
- Location: Making aviation exhausting, everywhere
Doesn't sound like that is the case here, but I have an engine installation STC on a certified aircraft that comes only with paper plans: every new bracket has to be made by the installer.
Even without the STC, you would never be able economically to reverse a transfer to OM. Although there is a list of requirements to do so in the CARs, TC makes it clear with the OM application that they consider the process to be one way, and they have (deliberately) avoided creating an approved process to reverse it.
Was the airplane inspected by TC after it was modified? Any modification affecting structure, performance, or airworthiness must be reported and approved. If that was done, then there's nothing left for you to do. If it wasn't, your C-of-A may not be valid.matt17 wrote: ↑Thu Sep 19, 2019 7:05 pmI looked at a Cessna 172 that is in owner maintenance and I am curious on the paperwork behind one "Mod" that was completed. Apparently there was a group of owners who all put their 172s into owner-maintenance, got together as a group and purchased one Sportsman STOL kit which they then used to copy, create and install kits in multiple planes (with only one set of STC paperwork). From my preliminary viewing the work appears to be well done (owner had multiple homebuilt planes previously and the group included at least one AME) but I am unsure on the legality over what they did. I am mostly interested in the "airworthiness" perspective not the commercial/ethics of copying someones work without paying for it.
You may not part mark, certify and sell parts which were not made under an approval.You can't just slap STC paperwork on top of homemade parts as then those parts would be classified as suspected unapproved parts, they were not made by the certificate holder or anyone else approved.
AWM 571.06 allows "repair" parts to be made by the installer under some circumstances. However, a newly made STOL kit, where that kit was not previously installed, really would be new parts, rather than a repair.
The modification authority for OM aircraft is a little fuzzy, simply because there is no means to actually approve mods on these aircraft through the aircraft certification office of TC. That leaves it up to the TC M&M Inspectors, who simply do not want all of the work involved in the evaluation, and are generally not staffed for that type of work anyway. On a few occasions, I have been asked by TC M&M to evaluate a mod on a flight permit aircraft, so they they might reissue the flight permit for a mod. In that role, I'm not acting as a DAR though, just a person that M&M knows can apply the evaluation process properly. So far, this has not come up for an OM airplane.571.07 (1) No person shall install a new part on an aeronautical product unless the part meets the standards of airworthiness applicable to the installation of new parts and, subject to subsections (2) and (3), has been certified under Subpart 61.
(2) No certification referred to in subsection (1) is required where
(d) a new part is installed on an aircraft that is operated under a special certificate of airworthiness in the owner-maintenance or amateur-built classification; or...........
As said before, unless there's a defect in the work, and a resulting fuss, a home made STOL kit on an OM Cessna which has been well done is unlikely to attract any unhappy attention. In the worst case, if it did become a problem, it could be declared to TC, and the flight authority reissued to include it. That's possible, though really low on TC's interest scale.
Aside from that - I would never buy an aircraft in the OM category. For the simple reason that it's value is radically decreased - (even though owners think they can ask just as much for it) The simple fact is - that you can not sell that aircraft outside Canada - so the re-sale market is extremely small and if anything happened - you could not even sell it for parts. So essentially - you end up with an aircraft worth next to nothing.
Well, except for the fact that it's a flying aircraft, what's one of those worth? More than next to nothing, if you're happy to fly it within Canada....So essentially - you end up with an aircraft worth next to nothing.
The plane in my avatar has been OM for nearly a decade, I've enjoyed more than 500 hours of great flying in it. It does not know that it's OM!
...and that's fine if that's what you like.Well, except for the fact that it's a flying aircraft, what's one of those worth? More than next to nothing, if you're happy to fly it within Canada....
My point was - that resale is extremely limited. Wether it's you, or your estate, or whatever. It's something to consider when you think about purchasing one. You can't fly t the US - you can't sell outside the country, and if you have an accident or the plane sits for years - you can't even part it out. That's going to have a serious impact on the sale price when it gets sold.
It sounds like the STOL kit install should not be a deal breaker if it was as well done as it appears. It would be the overall condition of the plane and the documentation both before and after it was converted to OM.
This is an important theme. When you can do the maintenance yourself, and record it properly, it means that it is a little more likely that things will get done sooner, rather than waiting for the next time the plane is at the shop, and, for my experience, on my OM plane, I will happily spend time tinkering, and making things just right, which I would be less eager to pay a shop those few extra hours, for something I don't really need, but would just like to be better.I know some owners that have their aircraft in the OM category and they are absolutely fanatical about their maintenance and their plane shows it. I think that an OM aircraft in some ways may be better maintained because the maintenance is more affordable.
As you get to know your plane better, you're better at preventing degradation, as you are more aware. And if you're stuck somewhere by a snag, you're more able to rectify it.
An inspection of the plane, reading the records, and meeting the owner/maintainer will tell you a lot about the condition of the plane, and thus it's value, be it certified or OM.