This thread goes back some years and it catalogues the reasons for the decline of piston twins.
It was already well under way when I started my PPL. There were still a lot of people flying them, but few were learning. A part of it was the annual checkride, which a SEP didn’t need. But in general more goes wrong on a twin – longer control cables, etc, all translate to more stuff needing care.
Also it’s been very obvious – though usually denied – that twins get maintained to a lower standard because they have a spare engine. I know just one pilot (a famous one though) who has stated that openly. He used the cheapest nastiest maintenance shop he could find (I agreed with his choice; I saw it myself 
).
I don’t know anyone who maintains their twin to a lower standard just because they have a second engine.
The annual checkride is not a problem. In fact if you do 10 legs of over 15 mins cruise in a year, the check ride is less onerous that the SEP checkride every 2 years and of course you don’t need to do that checkride if you have done the annual MEP checkride.
Maintenance is more expensive, after all you have 2 engines to maintain. But that is really where the extra cost is over an SEP.
The extra cost over the Cirrus would be the retractable gear maintenance.
Set against this would be the Cirrus parachute maintenance which I believe is quite expensive.
Yes also with fuel costs rising at the time the twin and MEP flying was taking a nose dive would probably have had a lot to do with their demise.
The Cirrus averages about 20 litres per hour less than a Seneca and IIUC the Cirrus is faster.
But I still like flying a twin, but if I do give it up, I would switch to ULM at my time of life.
And if I do tend to tune in to YouTube videos I will usually go to those where flying twins are involved.
By the way in your list of twins still in production as well as the Technam you forgot , the DA62 and the Piper PA44 Seminole.
Peter wrote:
Also it’s been very obvious – though usually denied – that twins get maintained to a lower standard because they have a spare engine. I know just one pilot (a famous one though) who has stated that openly. He used the cheapest nastiest maintenance shop he could find
It has been obvious from your posts and also other inputs in recent years that maintenance in the UK is a huge issue. I don’t see this kind of issue in Switzerland and also not very much in Germany or Austria, which is the places I see airplanes from most, but also understand that most other European countries have a level of maintenance which keeps the fleet at an acceptable level. “Shagged out” planes are comparatively rare, also due to pretty strict control by the CAA’s. If anywhere, the US has quite a lot of those, see things like “Jimmy’s world” or other channels which show in what shape planes often are over there. On the other hand, I’ve also seen some of the nicest examples of well maintained and cared for GA planes there, as the prices and owner involvement allow more.
gallois wrote:
The annual checkride is not a problem. I
It depends. Many people strongly dislike checkrides. I think Peter may have a valid argument for why there are many who chicken out from twins or even the IR because of this. I personally dislike checks too, but it would not keep me from doing what I like, but quite a few stay VFR and with their own plane and then hire an instructor to do the bi-annual “instruction ride” to satisfy the proficiency requirements.
gallois wrote:
Maintenance is more expensive, after all you have 2 engines to maintain. But that is really where the extra cost is over an SEP.
Maintenance is more expensive due to the 2nd engine and often complex and outdated systems, particularly in planes which have complex fuel, hydraulic and other systems which need care and skilled mechanics. Airplanes like the Travel Air/Baron range as well as the Twin Commanche and the Twin Cessnas have systems which are costly to maintain. Senecas as well as planes like the Cougar are much less critical there, even though the Senecas Turbo engines add to the cost.
gallois wrote:
The extra cost over the Cirrus would be the retractable gear maintenance.
Set against this would be the Cirrus parachute maintenance which I believe is quite expensive.
Comparing Cirrus maintenance to say a Mooney often shows that the Cirrus is more expensive. Shute maintenance is a big part in this.
gallois wrote:
The Cirrus averages about 20 litres per hour less than a Seneca and IIUC the Cirrus is faster.
The Cirrus range as well as larger SEP’s are about par for the course in fuel consumption to a Twin Comanche or Cougar and only slightly less than the Seminole or Seneca I.
gallois wrote:
But I still like flying a twin,
i would change to a twin today if I could afford it. Most probably a Cougar or a Twin Comanche, both of which have been my favorites for a while. Recently I also saw a very nicely equipped Seneca I which went for about 50k Euros within several days of being advertized. Yea, I would have liked that one.
I wonder if Part ML had been in force back as the beginning of the twin decline, perhaps as far back as the OPEC crisis in Europe, if the decline would have been much more competitive with the decline in GA generally. I think that was mid 1990’s or late 1980’s IIRC.
Mooney I understand what you mean about people not liking checkrides but under EASA I still have to have one every 2 years if I didn’t have my MEIR test every year.
Either If you have your own plane you call your local examiner to do the test and pay directly.
The difference being that you need an examiner instead of a FI. But most of the time the examiners here are also FIs and you don’t notice the difference. Either way you choose one that you feel you can get on with “sympa”.
It has been obvious from your posts and also other inputs in recent years that maintenance in the UK is a huge issue
It is an issue everywhere; the difference is that only some people are willing to openly post about it. Also few criticise their own country. It is one of the extra challenges of having an international forum. If you want to get a measure of the crap which goes on in [insert a country] you need to read their local stuff, and even then most people won’t go public with serious stuff because they want to sell the plane one day. I just get it on email; lots of it 
Many people strongly dislike checkrides. I think Peter may have a valid argument for why there are many who chicken out from twins or even the IR because of this.
It’s not black and white.
If you own your own twin e.g. Seneca then you can do a flight test for the cost of the avgas, so say €200 for 1hr. But if you just have a ME rating and want to keep it current, and have to rent something, then that flight test is gonna cost you say €1000. So, over time, the pool of ME rated pilots shrinks back to the portion who own a plane, and that pool shrinks over time anyway as the owners of the avgas twins drop out of flying (age, medical failed, retirement, etc), and there are very few newcomers – because twins are mostly for “serious flying” and the amount of that is reducing, particularly recently due to CV19 which has really shrunk the pool of pilots doing “serious travel”. Nowadays the newcomers (in Europe) to the twin scene are mostly DA42 buyers, of whom there are few, and again rental on those is very expensive. If you can find one for rent; not that common. One local FTO here stopped rental due to breakages. If you rent a plane out then you have to accept it will get trashed.
So the Euro-reg ME scene is eroding due to the above, and the N-reg scene is eroding due to other factors.
I wonder if Part ML had been in force back as the beginning of the twin decline
Most owners are unable to make use of Part-ML, due to the shortage of freelance EASA66 mechanics and hangars where work is permitted. Already much discussed.
As the pool of MEPs dwindle, so does the reasonable quality engineers who know how to maintain them, sensibly. In Europe they will tend to be engineers who can maintain N-reg.
gallois wrote:
But I still like flying a twin, but if I do give it up, I would switch to ULM at my time of life.
Why not choose both?
Sadly despite its low weight the Cri Cri is not a ULM here mainly because of the wing loading regulations. I did in fact look into it. I love the Cri Cri, it’s a lovely little aircraft to fly and to maintain.
gallois wrote:
Mooney I understand what you mean about people not liking checkrides but under EASA I still have to have one every 2 years if I didn’t have my MEIR test every year.
Well, you need to do a training flight with a FI. There are many FI’s I can choose from but only very few examiners. For ME even more so.
gallois wrote:
Either If you have your own plane you call your local examiner to do the test and pay directly.
Yep, that is how it works. For me it would be a revalidation first of both the IR and MEP, so basically a repetition of my ME/IR I’ve done decades ago. 30k upwards I suppose seeing that any Seneca today costs around 700 CHF/hr to rent. As I said, I’d love to but I am not rich enough. I can barely keep my SEP.
Peter wrote:
It is an issue everywhere; the difference is that only some people are willing to openly post about it. Also few criticise their own country. It is one of the extra challenges of having an international forum.
Well, I would do that if I had a reason. My maintenance is expensive, yes, but they are great people and do good work. And knowing the scene here a bit I would yet have to find a “shoddy” shop around here.
Peter wrote:
If you own your own twin e.g. Seneca then you can do a flight test for the cost of the avgas, so say €200 for 1hr.
Sure. But that is not the issue. Those who are chickening from exams simply keep the number of times they have to expose themselves to someone who will determine their knowledge and skills at an absolute minimum. That is not limited to flying. And there are a lot of people like that.
As I said, I would not shy away from it and of course I know people with whom these checks are ok, but I know many who simply won’t bother to include another stress factor into their lifes.
We offered the owner of a 310 the asking price and he didn’t want it. Offered the owner of another twin his asking price and he wants to hang on for a few weeks till he finds another aeroplane. You’d think it would be easier to spend money.
