The DA42 outsells all other piston twins by a large factor
That is virtually a given, however, given that Beech and Piper are making almost nothing, the Tecnam 2006 is really for the FTO IR training market, etc...
The electric system with the backup battery has been improved years ago
Correct me on this if I am wrong, but you will still get a double engine failure eventually - no? Maybe not on the 42 if at least one alternator continues to work, but on the DA40TDi you will.
I keep an eye on the DA42 but would like to see more years passed before spending money on the technology. Yet, a currently involved Diamond maintenance engineer I know very well tells me to firmly avoid, for private ownership... too many small hassles remain.
The EPA in the US will sooner or later affect the "LL" in 100LL. What's left then? Jet A.
100UL 
That is what America will develop - if pushed hard enough.
I agree Jet-A is the way in say China, but we are not China. China is big enough to do completely their own thing. They (like say Australia) could introduce a 5hr PPL/IR course and the rest of the world would not care.
China remains highly relevant to anybody involved in selling the technology, but to us "users" we have to work with what we have.
I suppose we agree it's very interesting but needs more time to develop a track record
What also doesn't help is the very large % of DA42s owned by FTOs, who for obvious business reasons do not wash their dirty linen in public, so maintenance problems do not have much of an incentive to be solved.
but you will still get a double engine failure eventually - no? Maybe not on the 42 if at least one alternator continues to work, but on the DA40TDi you will.
No, I don't think you'll get a double engine failure on the DA40Tdi. (ok, I'll get my coat...)
Correct me on this if I am wrong, but you will still get a double engine failure eventually - no? Maybe not on the 42 if at least one alternator continues to work, but on the DA40TDi you will.
The main issue is that the engine needs electric power to operate which is different from gasoline aircraft engines. It's not a problem per se but it needs to be properly accounted for. In the original DA42, there are two alternators and two batteries and two ECUs (the engine control) per engine.
One accident in Speyer in 2007 showed how this setup can lead to a double engine failure on takeoff. Both aircraft batteries were depleted and the pilot jump started both engines which is in violation of the POH procedures (only one engine may be jump started but that's a rather minor mistake and shouldn't bear the death penalty). The alternators were thus both charging the depleted batteries and providing all the power for the electric system (including the engine control), all 4 components (2x alt, 2x battery) connected to one system.
After takeoff, the pilot retracted the gear which is operated by an electric motor and this additional power draw caused the voltage of the electric system to drop below a critical level which made both ECUs and thus both engines quit.
Diamond solved this by installing additional batteries for the ECUs. This addresses the issue and several others (like a previously fatal master relay failure) but a proper fix would have been to have a true dual bus system like other aircraft. This was back in the good old days of Mr Thielert vs. Mr Driess public fights. Diamond stated it was an engine problem and Thielert stated it was an issue of the electric system of the aircraft.
Until today, the electric system of the DA42 is not adequate and miles away from a proper dual bus system that other aircraft have.
Agreed, but a dedicated alternator for the engine would be the easy and IMHO smart solution.
Lycoming's electronic ignition (which is not going anywhere paperwork-wise, but it does "fly") is completely autonomous.
I actually think that a "flat battery = engine stops" is stupid even in cars. I had it happen once (in a Toyota!) when a leaking oil seal was dripping oil onto the alternator, burnt out the slip rings, so the battery was not charging, and being at night the whole thing didn't last long...
Diamond may have fitted extra batteries but batteries are a poor solution. They always fail eventually (usually within a few years, given dumb charging methods) and they create extra maintenance costs, etc.
I thought the only proper dual bus light-GA plane was the Cessna 400.
The DA42 is impressively expensive maintenance wise.
It is a great pity that the developpers of dieselengines are going so slow. Continental invested in the 1st gen SMA engine; while SMA now has a much improved 2nd gen. If only they and other manufacturers can kick out a few more models and choices at a good price level and a good weight .. Diesels will be firmly in business.
As Asia becomes the growthmarket and will only accept Jet fuel (no way they will want to see environmental unfriendly stuff like Avgas), all manufacturers will have to come up with Jet solutions.
It is encredibly stupid to see all this "current" technology still being pushed as modern while it derives from b.c.
I presume around 2016-2017 we should see a lot more choice. By then SMA will also have a big version around 400bhp .. ideal for the Duke, C3/4xx and Malibu kind of Aircraft.
The DA42 is impressively expensive maintenance wise.
So what's your estimate, how much yearly, how much per flight hour?
As Asia becomes the growthmarket and will only accept Jet fuel (no way they will want to see environmental unfriendly stuff like Avgas), all manufacturers will have to come up with Jet solutions.
Well, from everything I've seen there, they couldn't give a rat's a** for the environment!
IMHO, the availability of 100LL is the issue. In parts of the world where GA is used for public transport, i.e. Africa, Oz and increasingly Asia (at least in parts), you already run into huge 100LL supply issues. Granted, the mining companies (which account for a massive portion of GA ops in these parts) can quite easily have a bowser on site, but it's still a right royal PITA. My guess is that IF a reliable engine that can power C182s and the C200 series as well as light twins on Jet-A comes to market, a lot of operators will swap out their gas burning Lycosauri PDQ.
I cannot tell you
what I do know is that I looked into a DA42 from 2006 with 1950hrs which had been sitting for a year due to a bankruptcy. It already had the 2nd engines.
there were 2 quotes for getting it airworthy again: both were 50k ex vat +.
of which:
€ 12.500 for the 2000hrs inspection € 3.000 for 1 prop overhaul
all else was lots of small stuff ... no engines .. no gearboxes. I checked with my own maintenance company and basically he said that it was crazy how much maintenance is necessary for such a modern Aircraft but their experience was the same .. They need a whole lot of maintenance... It is nowhere near the maintenance of a piper Seneca for example.
what I do know is that I looked into a DA42 from 2006 with 1950hrs
I was considering that one but gave up when I realized that this 50k didn't cover any major component.
The failure of diesels in the market results from their being a solution to a non-problem for the majority of the existing market, combined with their being little possibility of growth in those areas where GA is repressed by over regulation and heavy taxation (regardless of fuel used)
Neither avgas availability or tax avoidance are issues for most existing GA buyers, and as a result the potential market for diesels is small, driving per unit development costs sky high. That results in a complex under-developed product which requires a huge amount of maintenance. I’d never looked closely at a Thielert until this year, but upon doing so at an airframe manufacturer facility, I was shocked at the complexity and fiddliness of the whole thing. Belt driven cam? Are you kidding me?
In addition, the majority of aircraft owners don’t actually fly all that many hours and regardless of SFC their needs and pocketbook are best served by the simplest, longest lasting machine they can buy. Existing aircraft engines have had a lot of development effort put into them, eliminating every heavy, complex feature as a goal. They are also served by a competitive marketplace of parts vendors and overhaul companies and they just work better for the buyers.
