Cirrus Spam

Philip Greenspun's Homepage : Philip Greenspun's Homepage Discussion Forums : Aviation : One Thread
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I know the selective use of stats will drive people on this forum
nuts, hence the need to post!

Thaough you might get a kick out of it. Follow the link on why spin
recovery is no big deal: spin.aspx
Is it true that "the mainstream general aviation four-seat designs
such as Cirrus, Cessna (182, 350/400, etc), Diamond, Mooney, Piper
etc. are not certified for spins. Few 4-seat designs have ever been
tested or certified for spins."?


-- fabio savoldelli, May 19, 2008


This is plainly false. In the old days, any single-engine airplane had to be spun and recovered as part of its FAA certification testing under FAR 23. So a Cessna 182, Mooney, or Piper Warrior has been spun and recovered by a test pilot. The DA40 went through quite a bit of spin testing and then additional spin testing when the larger fuel tanks were offered as an option (passing the spin recovery there required tacking on a larger rudder). The DA40 with standard fuel tanks almost surely could be certified to the higher standard of "spin-approved", which would allow ordinary CFIs with students to go out and spin them, but Diamond chose not to invest the time and effort.

Starting in the 1980s, the FAA began to allow an airplane to be certified as "spin-resistant". If you could show that it was very tough to get into a spin you could get relief from the spin recovery demonstration requirements.

The Cirrus was certified under two theories: (1) it would be difficult to get into a spin, due to the design of the airfoil where you get an inboard stall long before the outboard portion of the wing (ailerons) would stall, and (2) you could recover using a parachute.

So... virtually all four-seat airplanes flying have been spin-tested with relatively straightforward recovery demonstrated to the FAA.

What planes don't have to be spin-tested? Twins. Don't spin a Baron; you might well have been the first person to try!

-- Philip Greenspun, May 19, 2008

I note the link above has an error: it is

I originally posted as a spoof, but for a company that is asking me to trust them with my life, this kind of thing may not be the best stratagy. What other errors are on that web page??? How lame.

-- fabio savoldelli, May 19, 2008

I'm very curious where they got their DA40-XLS versus SR22 numbers - the numbers they listed for the DA40-XLS for cruise speed, climb rate, etc. are CONSIDERABLY lower than the ones Diamond claims in their own literature. It's like they took the numbers for a first-generation DA40 and assumed that the XLS (which has some aerodynamic tweaks and a Powerflow exhaust, considerably improving performance) was the same.

If they put the legit manufacturer's numbers side-to-side, I'd have more respect for Cirrus.

-- Mike Zaharis, May 26, 2008

Sorry - meant SR-20

-- Mike Zaharis, May 27, 2008