Interesting article. The Diamond statistics are astounding. Still zero post crash fires.

I find it interesting that the chute system does not have post "landing" cutter to separate the chute from the aircraft. There have been reliable systems out there for a while that do this. One of the folks who survived a deployment and landing was killed because high winds drug them and the airplane over rough terrain.

I was happy to believe that for the longest time. But there is one that burned after impact, NTSB report and all. ERA11FA085

http://www.ntsb.gov/aviationquery/brief ... 5210&key=1

Two DA20s burned after impact, but both of those went into powerlines which is cheating.

If Diamond has some engineering game-changer that makes their planes never burst into flames or burn after crashing, I sure hope they make that miracle available to all other airplane manufacturers.

I think, in my own simple mind, the hot engines, sparks, and spilling avgas have a chance of burning, no matter from what container the avgas spilled. No?

Yes, but you can mitigate that risk somewhat during design. You just have to separate fuel from ignition source as much as you can, few ideas come to mind how to try to keep spilled fuel as far away from engine as possible.

Yes, but you can mitigate that risk somewhat during design. You just have to separate fuel from ignition source as much as you can, few ideas come to mind how to try to keep spilled fuel as far away from engine as possible.

No miracle. The fuel is in welded aluminum boxes sitting between dual spars. To breach the tanks, you need to have hard enough of an impact to destroy the front spar. In the crash I posted, that was the case, but only after he hit a stand of trees hard enough to scatter the wreckage over 300ft.

Cirrus, Mooney and Cessna have the fuel lapping directly on the inside of the skin covering the wing nose. Any impact that whips the wings forward and aft or any impact with trees or brush will breach the tanks.

Bonanzas and Comanches with their butyrene shopping bags inside of the skin are somewhere in between.

There are three more factors:

- DA20s are fairweather planes as they are not IFR approved (no conductive mesh in the skin, no bonding). When Cirruses are out in yukky weather, they sit in a nice warm hangar.
- DA40s don't fly much. For some reason you will see 46 Cirri in the IFR system when there are 2 DA40 in the system. So either the diamond owners don't fly, or they ALL blocked their N numbers.
- There is a magic attraction between Diamond aircraft and water. Three of the fatals with high-speed impacts involved water, heck one of them managed to find a lake in Arizona . Who knows how they would have ended had they hit structures or rocks.

No miracles. The fuel tank is designed for a 26 g crash, which is more than we can survive.

The main tank is behind the passengers in the fuselage. Scary at first thinking about the fuel being behind you, but wings are often punctured in a crash. Too much surface area to protect.

(Is the extended fuel version behind as well?)

There have been lots of advancements in post crash fire protection focused on fuel containment. Break away valves that close off the fuel flow when the line is ruptured, foam (okay, that's old), etc.

The NTSB report is interesting. It doesn't really describe the level of post crash fire, or why. Could have been from the exhausts on the fiberglass, oil leak, or the vegetation. Both tanks being separated from the crash is a bit of a giveaway: this was a bad crash.

Do you know more about this crash? If fuel starvation was a problem, it wouldn't be fair to count this either way.

After reading the report, I'm not convinced Diamond's record has changed.

I stand corrected on fuel tank location and strength.

Are they foam filled?

I am a DA-40 owner. I can assure you that there is no fuel tank located withing the fuselage unless you have installed a ferry tank. They are located, as was posted earlier, between the spars on the wings.

Florian,

Good to hear from you. It's been a while.

You're right about not seeing DA 40s flying. I just don't see them anywhere, on the ground or in the air. Maybe it's me.

On the other hand, you can't sling a dead cat without hitting a Cirrus around here.

Any insight on relative production numbers to Cirrus airplanes?

The DA 20 is a whole different airplane and lineage.

Are the tanks foam filled? Do you know if they do anything with the lines?

The tanks are not foam filled. I can see the aluminum tank when filling them.

I was told that the design does not have any fuel lines within the passenger compartment.

Nothing like getting in a plane and looking over at the sight tube inside the cockpit that shows you your fuel level?

From the Diamond website:

"In fact, we haven't been able to find any significant fires in Diamond airplanes, which we find to be a remarkable record due in part to the airplane's design."

Depends on what your definition if "significant" is.

Some more digging:

DA 40 uses braided stainless steel lines, not aluminum tubes. These are MUCH tougher, and being flexible, allow for more damage tolerance. Still, better than glass.

Layton, what made you chose the DA 40? I think they're very attractive from a lot of perspectives, but I suspect most Bo or Cirrus owners don't want to give up the speed.

Again, my apologies to the DA 40 folks. The 20 has the aft tank.

For punishment, may I suggest hours of flying around in one?

Come up to Potomac, they have one.

As for the long-range fuel. I believe the regular DA40 has two fuel cells per wing , the long range has 3. The DA20 has a tank in the fuselage, aft of the passenger compartment (so if you mangle the plane enough to get to that tank, you are probably toast from the impact alone).