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It appears more companies are seriously considering alternatives to 100LL. Teledyne Continental announced that they are planning to "aggressively" develop a diesel for certification in the next couple of years.
Diesel is more expensive and not as accessible, however, long-term environmental impacts are lower due to a higher efficiency and hopefully new technology with emission control. Would you consider this an option if you are buying a new plane?

Anais,
I'm curious why you say it's more expensive. On average Jet A seems to be a few cents cheaper per gallon than 100LL and when comparing the Skyhawk SP vs the Skyhawk TD (that's the turbo diesel version) the TD burns only ~4 gallons per hour at cruise as compared to the SP's roughly 9.5 gallons. While it's true the actual aircraft may cost more, but I've been lead to believe that operating costs for a diesel aircraft will be considerably less than a 100LL burner.

Also, as for fuel availability, I keep hearing rumblings about fewer and fewer refineries making 100LL and that it may not have the same availability we see today. I'd be interested if anyone had real information on that issue.

My understandings are in alignment with ebrendan. JetA (what passes for diesel in the US aviation industry) is generally cheaper and the engines are more efficient. One thing that I believe will cost more besides acquisition, however, is that they currently have a TBR (Time Before Replacement) vs TBO (Overhaul) and that time is generally less than a 100LL engine.

You are absolutely right. Let me reword.
Diesel aircraft tend to be more expensive and there are less options for make/model. Jet A appears to vary around the country but the efficiency of the engine allows lower operating costs. I agree with Landis, I understand that each engine time is less before overhaul. This certainly could mean altered maintenance costs. All of this is new territory to me and I would love to hear from somebody who is knowledgeable in this area.
Is this a serious consideration for people in the market for a new plane?

My sense is that we're going to see more diesel options in the future and the economics of operation will make them compelling options. As engine manufactures put in the R&D time, we'll likely see some of our favorite airframes available with with diesel engines.

One data point... The owner of my FBO/Flight School is "strategically" (i.e. in the next decade or so) planning to switch his fleet of 172's to the new 172TD-- The only lease-back agreements he is considering are with the 172TD, although there is currently a significant wait from Cessna.

Also, 100LL is one of the last remaining fuels to contain Tetra-ethyl lead. It's nasty stuff and has almost no remaining industrial uses. If there is concern over the future availability of AvGas, it's no doubt linked to Tetra-ethyl lead.

But you asked for expert input-- None of which is contained in my post.

Here's an interesting article on diesel vs avgas and comments to follow. I wasn't aware of this operational downfall of diesel engine-intense vibrations. An AD for Thielert's new Centurion 2.0 came out a couple weeks ago, making it mandatory to install a bracket that prevents cracking in a high-pressure line due to this.

http://www.avweb.com/blogs/insider/AreD ... 391-1.html

More information will be released in the Aviation Consumer.

I can't find it online, but Flying Magazine's April issue includes a review of the Cessna 172TD. Generally positive, but there are a few drawbacks.

One of the biggest drawbacks I've seen from the new diesel engines is that at TBO, there's no overhaul option. It's an engine replacement every time. That would get very expensive if you haven't planned for it.

Now, you could say "take the money you save in gas and keep it toward the engine replacement." Right, like anyone would have the discipline to do that!

Jeff

I spoke with a Cessna rep at Oshkosh and was told the 172TD program has been scrapped. While this was somewhat anticipated after the shenanigans t Thielert, I hoped they were looking for an alternative engine supplier. But as the Cessna rep said "That was THE supplier".

I guess we should be talking about this now: http://blog.wired.com/cars/2008/04/in-an-aviation.html