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Drawing up my own maintenance program - SDMP - and a maintenance company refusing to operate it

My maintenance company has told me that one of my Cessna 150’s has an impending ARC and therefore has to move off LAMP and they would like me to draw up the maintenance program. However I am completely clueless about this. I done some internet digging but still don’t understand it.

I downloaded CAP 1454 which makes it sound easy. I’ve also downloaded the template Aircraft Maintenance Program but after that it all appears to be in Latin.

So daft question time

I can’t find the Cessna 150 maintenance manual online. However I can find the Service manual is that the same thing?

What I would like to do is maintain my aircraft in the same way that this aircraft would be maintained if it was on the N reg. My reasons for this are that its probably the worlds most widely used maintenance program and as far as I am aware they don’t have any safety issues.

I also want to get rid of crap like the 6 year prop overhaul, 10 years replace seat belts. I would also really don’t wont to go through the expensive 150 checks either. So the FAA 100 hour and annual checks would be fine by me. However I would still like to replace the oil every 50 hours.

Also I may like to add to the fleet in the future and over the years I have seen some really tidy (and cheap) C150 for sale however the engines have been out of the 12 year lifetime and so can’t be used for instruction. So I would also like to get rid of this to.

Could anyone give me idea if what I want to go is possible or even better has anyone done this already and give me their filled out template.

You might want to discuss this with your maintenance organisation. From your post the seem to be reasonable, and might be help you to design your AMP. They might also help you to furfill documentation requirements. Even though it seems always simplistic, you would need up to date manuals, which for same aircraft are not available free of charge. Apart from aircraft maintenance manuals, you might also need other manuals for components to determin correct maintenance. You might also need service letter, and bulletins from other components. Which all together makes having up to date maintenance manuals for a single aircraft quite expensive. Your maintenance organisation will have these manuals, and could advise you on which items make sense, which not.

For example, I have seen some aircraft, not performing the alternator 500 hours inspections, while on some aircraft the alternator lives for maybe 600 hours without service. If you own and aircraft like that, it doesn’t make sense, not to perform such an inspection, as it will actually cost more to replace the alternator every 600 hours, then doing an inspection every 500 hours.

Another thing is that the minimum inspection program is the bare minimum you have to do, you are offcourse always free to perform more / better maintenance if that suits you better. Performing the absolute bare minimum is IMHO only a saving on short term. After a while you would get an ARC with a lots of expensive things too fix at one single point, and some items might be more expensive to replace / repair then performing a little more maintenance on it whole the time.


In mi opinion, the best approach seems to be to adhere to the MIP. Why would you force yourself to perform more maintenance than the minimum required? Do all the maintenance you want, but don’t force yourself in advance to do it.

Last Edited by Coolhand at 23 Nov 12:46
LECU - Madrid, Spain

You also need to look at the way you operate the aircraft, for instance in the U.K. A glider tug would come under these regulations.

So a DR400 operated as a tug performing six landings an hour should have a maintenance program that reflects the high rate of landing gear usage as apposed to a DR400 that is used for long distance touring would have a program that focuses less on the landing gear and more on other issues.

Both myself and the maintenance company are having a little difficulty with this. The SDMP that we have submitted has been rejected. In fact its been rejected on pretty well everything we a have tried to achieve. For instance we have been told that we have to do 50 hour checks. We have to do the 6 year prop overhaul, Engines have to be replaced when they reach TBO. After some discussion and despite being told its not for us to tell you what to do. Its for you to tell us what you are going to do and then we will either agree or in this case disagree. However with the discussions that we have had it would appear that what they are suggesting for a 100 hour check is now not far off an annual inspection.

We have been told that we have to comply with the MIMP AND the Design Approval Holder Maintenance Manual. Also anything that is recommended eg 6 year prop overhaul we have to comply with.

Now all over the internet I have read that people have moved to 100 hour checks. And how great things are and how they no longer have to undertake the 150 hour inspection. Engine can be run on condition, Engines older than 12 years can be used for instruction but I have yet to come across anyone in the flesh and that is certainly not what we are being told.

Is anybody able to give me some help here? I would love to see a copy of a SDMP for a similar aircraft on both the UK reg and another under a different European registration. I can understand that someone wouldn’t be keen on them giving me a copy of their work but even just a snippit would at least give us an indication of what we are doing wrong.

Last Edited by Bathman at 25 Jan 07:25

Bathman, sorry to hear that you have ended up in a discussion regarding this. Is it the UK CAA that are not accepting the SDMP?
I am not familiar with the maintenance manual of the Cessna 150 but does it say anywhere in there that you shall do a 50 hour check?
If not, ask them to present some evidence for their statements.

The prop overhaul and engine TBO can easily be deviated from, that is basically the whole point of the SDMP…

Here is the “Easy Access”-version of Part-M.

M.A.302 (h) clearly says that you shall comply with either the MIP OR the:
“instructions for continuing airworthiness issued by the holders of the type-certificate, restricted type-certificate,
supplemental type-certificate, major repair design approval, ETSO authorisation or
any other relevant approval issued under Regulation (EU) No 748/2012 and its
Annex I (Part-21)”

If you have a G-reg I would suggest that you contact Steve Horton at the UK CAA. He is a part of the Part-ML Task Force and might be able to convince his colleagues of what is right and wrong in this matter. Any TBOs from the manufacturer can be deviated from, no matter if it is clever or not.

Looking forward to here how this unfolds. Good luck!

Last Edited by Fly310 at 25 Jan 09:44

6 year mandatory prop overhaul on a fixed pitch prop? What happened to the proportionate and risk-based approach we were supposed to be getting after the Red Tape challenge?

Andreas IOM

I don’t get it – I thought it was a “self-declared maintenance program”, and the authority is not in a position to reject it.

It needs to comply with the MIP (minimum inspection program) and a very limited set of limitations in the maintenance manual, type certificate, or ADs.

The only intervention happens if something breaks and the engineer/CAMO thinks it had something to do with the SDMP, in which case you have to fix it before the ARC can get issued.

Did I misunderstand? It is all here

Biggin Hill

As per CAP 1454 from the link above.

Under the revised regulation,

an owner may develop an AMP for their aircraft that does not require an approval from the CAA.

This is called a SDMP. The owner may decide to base the SDMP on the manufacturer’s recommendations or the EASA published Minimum Inspection Programme (MIP). In all cases the SDMP must not be less restrictive than the MIP

So how did the CAA get involved…

Southend, United Kingdom

I wonder if somebody asked the wrong question of the CAA. Did you/your maintenance company inform the CAA of your new SDMP, or did you ask them to approve it? Might just be as subtle as that.

Fly310 wrote:

Is it the UK CAA that are not accepting the SDMP?

I would also be interested in the answer to this question.

EGTT, The London FIR
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