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Re: Good news for Diamond?

Posted: Tue Jun 12, 2018 1:27 pm
by TimS
Karl wrote: No need really, a Diamond is safer without CAPS than a Cirrus is with it, especially the Jet A1 versions with the lower risk of fire.

During a quick review of fatal accidents from October 2006 to present I found 13 DA42, 20 DA40, 29 SR20 and 84 SR22. I tried to separate out the Avgas from Jet A1 DA 40 accidents but it was impossible to do reliably.

Someone I spoke to said that a stalled DA40 actually descends slower than a Cirrus with the CAPS deployed. Wouldn't fancy trying it though. :shock:

I have flown in many aircraft whilst wearing a parachute and the briefing was always that the only reasonable time to use it was in event of a fire or major structural failure. Using CAPS in event of a fire wouldn't be much fun and structural failure is few and far between if the aircraft is operated correctly.
Looking at accident counts without context is kinda pointless.
To show how pointless; according to flightaware.com; there are 40 SR22s flying now and being tracked. There are 6 SR20s flying. There are 2 DA40s and 1 DA42.

Who ever did the number crunch comparing the DA-40 stalled descent rate to a Cirrus likely needs more instruction and some basic math skills (yes, I am being cheeky). By definition, a stalled wing means no lift. If you have ever stalled the DA-40 and held it for a three count you will see an amazing drop in altitude (was rather fun actually). Same in any plane, lose lift and the plane comes down. Now there have been periods of people talking about the DA-40 parachute mode, with flaps up, trim all the up, and power to idle; will give you between six and 12 knots vertical component and and roughly a 50 knot horizontal component. This combined speed is about five times greater than the Cirrus with an average of 11 knots vertical plus what ever the prevailing wind speed is; so unless you comparing flying in a tornado, it is no real comparison.

If you are discussing military aircraft and parachutes, there is a reason for such a briefing. The exit from a military craft in a parachute is a high risk maneuver, and the military does not want the plane crashing into a civilian environment. The whole plane chute for a Cirrus is a completely different animal. First it is not a high risk maneuver, second the vast majority of pilots are not "professional" and constantly being trained (therefore the risk of a crash landing with injury is significantly higher), third the downside risk to others on the ground is rather small with the whole plane coming down (they make a surprising amount of wind nose, and really obvious with the huge chute).

Tim

Re: Good news for Diamond?

Posted: Tue Jun 12, 2018 1:51 pm
by CFIDave
No math skills required to put a Diamond into a full stall, hold it there for considerably more than 3 seconds, and read the VSI to determine descent rate. I agree that vertical speed doesn't tell the entire story, since a stalled aircraft will still have a horizontal velocity component that will almost always be greater than the drift (wind speed) of a Cirrus under parachute. (And technically speaking, a fully stalled wing still generates some lift). I was NOT suggesting that someone use "parachute mode" in an emergency; with a loss of power always fly the plane under control all the way "into the crash."

But the stability of a Diamond and its docile handling during a full stall tends to blow the minds of pilots who fly other planes, which is why "parachute mode" makes such an effective sales demo.

Re: Good news for Diamond?

Posted: Tue Jun 12, 2018 3:10 pm
by TimS
CFIDave wrote: But the stability of a Diamond and its docile handling during a full stall tends to blow the minds of pilots who fly other planes, which is why "parachute mode" makes such an effective sales demo.
Agree, I would go a step further. The combination of long wings giving a perception of steeper banks, high aspect ratios, and docile handling actually reduces pilot error in critical phases of flight causing a catastrophic event. When you look through the accident history database you will find that pattern to landing and slow flight errors are much less common in Diamond than in other aircraft. These accidents make up a very significant portion of pilot errors.

Tim

Re: Good news for Diamond?

Posted: Tue Jun 12, 2018 3:47 pm
by Rich
To be fair, the notion of pulling a chute (assuming you remember to pull power) is a more easily executed action for a non-pilot than riding a stall all the way to the ground. On the other hand, it's turned out to be that the chute has almost always been pulled by the PIC, not other occupants. And you can practice the stall-riding riding technique. Not so practical with chute-pulls.

What's more likely: Your husband having a fatal heart attack during the 30 or so hours you might fly with him during a year, or during the other 8730 hours?

What's more likely: Your husband having a heart attack while flying (a statistically VERY rare event) or his having a metaphorical "brain fart" (happens dozens of times a day - at least)?

But these are rational analyses, so never mind ...

Re: Good news for Diamond?

Posted: Wed Jun 13, 2018 12:24 am
by Lou
I thought I heard the Cirrus CAPS was necessary for certification, because the aircraft is unrecoverable in a spin? The DA-40 is easily recoverable, as the Diamond Youtube video demonstrates, although it is not certified for spinning.

Re: Good news for Diamond?

Posted: Wed Jun 13, 2018 12:52 am
by CFIDave
A Cirrus will recover from a spin using its flight controls (perhaps not as easily as a DA20/DA40), but the company never had to demonstrate that during certification because it demonstrated using the parachute for spin recovery. Therefore Cirrus pilots are taught to pull the 'chute to recover from spins.

Re: Good news for Diamond?

Posted: Wed Jun 13, 2018 1:56 am
by TimS
CFIDave wrote:A Cirrus will recover from a spin using its flight controls (perhaps not as easily as a DA20/DA40), but the company never had to demonstrate that during certification because it demonstrated using the parachute for spin recovery. Therefore Cirrus pilots are taught to pull the 'chute to recover from spins.
Actually it was required by EASA. Chute is still more likely to recover and uses less altitude.

Tim

Re: Good news for Diamond?

Posted: Wed Jun 13, 2018 10:09 pm
by Colin
Diamond should just sell the wife a chute.

Re: Good news for Diamond?

Posted: Thu Jun 14, 2018 12:04 am
by blsewardjr
Would need one for the dog and kids as well!

Re: Good news for Diamond?

Posted: Thu Jun 14, 2018 2:14 pm
by Keith M
And instead of a rocket in the tail, explosive bolts for the canopy. What could possibly go wrong?