I’m in the purchase of buying a TB20 on the G-reg. Thankfully, despite brexit, the EASA part-ML rules have been transposed into UK regulations and look set to stay. For the last few years, I’ve owned homebuilt aircraft – coming back to the certified world, it’s good to see the regulations have massively improved.
There do seem to be a few tradeoffs in Part-ML which need some thought. Having managed and performed my own maintenance on homebuilt aircraft – and built most of an RV14 – I’m not overly worried about doing it myself. Also, there is no based maintenance org at my home base (Oban EGEO).
CAO/CAMO vs owner-declared AMP
As an owner, you can declare your own maintenance program, or have a CAO/CAMO create one and sign it off for you. The latter makes the ARC process simpler, does anyone have a view on whether it’s worth it?
CAO/CAMO managed maintenance vs owner-managed
Once the AMP is created, you can either manage the maintenance yourself or have a firm do it for you. Again, any views?
Design Approval Holder vs Minimum Inspection program
Is there any reason you would use the DAH program over the minimum program that’s laid out in the regs? Obviously, you need to check the TCDS and section 4 of the MM and include those if you’re using the minimum programme – but for a TB20 that’s pretty much a moot point, there’s next to nothing in section 4 of the MM, and absolutely nothing in the TCDS.
Either way we need to follow (and document) all ADs, and sensible maintenance practice includes a few checks that are not on the MIP (including many from the maintenance manual, such as TB-specific control surface lubrication and anti-corrosion treatment).
Does anyone use the DAH program…?
Excellent questions!
jwoolard wrote:
CAO/CAMO vs owner-declared AMP
As an owner, you can declare your own maintenance program, or have a CAO/CAMO create one and sign it off for you. The latter makes the ARC process simpler, does anyone have a view on whether it’s worth it?
Depends, among other things, on the price of the CAMO. A CAMO definitely saves time and hassle (creating AMP, tracking maintenance). Apart from that, liability is a factor.
CAO/CAMO managed maintenance vs owner-managed
Once the AMP is created, you can either manage the maintenance yourself or have a firm do it for you. Again, any views?
I never thought of it like that. I believe your plane can either be under CAMO contract or not.
So only if the CAMO manages the plane it can create the AMP and track maintenance.
jwoolard wrote:
Design Approval Holder vs Minimum Inspection program
Is there any reason you would use the DAH program over the minimum program that’s laid out in the regs? Obviously, you need to check the TCDS and section 4 of the MM and include those if you’re using the minimum programme – but for a TB20 that’s pretty much a moot point, there’s next to nothing in section 4 of the MM, and absolutely nothing in the TCDS.Either way we need to follow (and document) all ADs, and sensible maintenance practice includes a few checks that are not on the MIP (including many from the maintenance manual, such as TB-specific control surface lubrication and anti-corrosion treatment).
Does anyone use the DAH program…?
Generally it’s a possibility to use the MIP, but then do more in the field (eg 50hr inspections).
Part-ML includes risk management („should“) and I believe using „only“ the MIP could mean some trouble in the worst case when it could be deemed that some maintenance pertaining to certain types was omitted because it’s not part of the MIP.
Snoopy wrote:
I never thought of it like that. I believe your plane can either be under CAMO contract or not.
So only if the CAMO manages the plane it can create the AMP and track maintenance.
That’s a good point, on reflection I think you’re right.
I’m currently leaning towards no CAMO and an AMP based on the MIP but:
If anyone has a recommendation for a Part-66 engineer who can help with maintenance in Scotland, I’d love to hear by private message…
Sounds like a good plan.
You can use the MIP for the AMP, and do „more“, e.g. 50hr inspections without having them in your AMP.
So if you’re on a trip, and it will be 55 hours before you do the 50hr inspection, you’re not in a tight spot.
It’s important to keep in mind that while AMP requires no official CAA approval, it still requires a review by the airworthiness review engineer issuing your ARC.
Regarding 50-hour inspections, it’s good to keep them simple enough to be performed by the pilot-owner under ML.A.803.
I prefer to follow the DAH and make deviations from that instead of using the MIP. The DAH is more adapted to the aircraft.
Ultranomad wrote:
Regarding 50-hour inspections, it’s good to keep them simple enough to be performed by the pilot-owner under ML.A.803.
100%, I think that’s really important. No reason they can’t be.
Ultranomad wrote:
requires a review by the airworthiness review engineer issuing your ARC.
Even if no CAO/CAMO is involved, it seems worthwhile to have the engineer or organisation that will do the signoff cast an eye over it.
Fly310 wrote:
I prefer to follow the DAH and make deviations from that instead of using the MIP. The DAH is more adapted to the aircraft.
It’s a fair point, but in the case of the Socata maintenance manual, you would be specifying tens of deviations to keep things on condition. I’m not sure that’s any better than the MIP with about the same number of extra checks taken from the manual.
Ultranomad wrote:
Regarding 50-hour inspections, it’s good to keep them simple enough to be performed by the pilot-owner under ML.A.803.
Is it ok to just omit them in the MIP AMP and do your own 50 hour inspection (oil change) „additionally“?
Snoopy wrote:
Is it ok to just omit them in the MIP AMP and do your own 50 hour inspection (oil change) „additionally“?
Whichever maintenance approach you take, it’s always best to have the formal document properly reflect your actual practice.
By the way, the Czech CAA did a wise thing by publishing AMP recommendations for the common types of Czech design. They contain summaries of old DAH programmes with the items colour-coded by category: mandatory, optional, or “optional but strongly recommended”.
jwoolard wrote:
Even if no CAO/CAMO is involved, it seems worthwhile to have the engineer or organisation that will do the signoff cast an eye over it.
Even if no CAO/CAMO is involved, someone must still issue an ARC (see ML.A.901, ML.A.903) and review the AMP. The least onerous option is a freelance engineer with a proper authorisation.
jwoolard wrote:
That’s a good point, on reflection I think you’re right.
I also think you are right. Under part-M, there was the concept of a “limited contract” with a CAMO, where the CAMO manages the aircraft according to an owner-declared AMP. That possibility seems to be gone in part-ML.
My club used that possibility for a while to run an engine on condition indefinitely. Although the CAMO agreed, he wasn’t very keen so I can imagine the possibility was removed in part-ML because very few CAMO:s wanted to enter into such a contract.
(The engine – a Lyc. IO-360-L2A – was eventually overhauled at 3400 hours. Not because of any indication of problems, but because some club officials got nervous. Contrary to popular belief by some, you don’t get to decide everything by virtue of being an aeroclub president!)
