On Sun, 29 Oct 2006 01:37:47 -0700, I wrote:

I haven't run the fleet accident rates for the Cirrus....guess maybe I'll have
to take a look. If, as you say, the accident rate is about 0.75%, that's in the
ballpark of the 172.

Just completed a cursory look at the accident data.

A summary on the process: I previously downloaded the NTSB accident report
databases for the years 2002, 2003, and 2004 and developed various database
queries to allow analysis of accident causes. I've also downloaded the FAA
registration database every January for the past ~7 years. I have developed
various tools to allow comparison of accident rates.

Rather than compare the Cirrus accident rate to those of the overall fleet of
Cessna 172s, I have compared it only to the accidents involving 172s
manufactured since 1994 (yes, production started a few year after this point).
I have included any Cessna 172 listed with a post-1994 manufacture date, PLUS
all Cessna 172R and 172S models since the year of manufacture is not always
available).

For both aircraft, I have included only those accidents that occurred in the
United States.

After looking at my tools again, I see my earlier posting mis-stated my method
of determining the total fleet size of a particular aircraft. I had stated that
I used the January 2005 FAA registration database to determine the fleet size.
This is incorrect. In reality, my tool determines the *average* of the fleet
size from January 2002 to December 2004. It is this average that is used to
calculate the fleet accident rate.

There are other ways of making these determinations, but it by using the same
processes for both types of aircraft, the *relative* rates for each can be
obtained.

Ah, the heck with it...on to the data:

Cirrus Accidents during subject period: 20 (over a 3-year period)
Late-model 172 Accidents: 103(over a 3-year period)

Average Cirrus Fleet Size: 783 aircraft
Average Late-model 172 Fleet Size: 1993 aircraft

Average ANNUAL Fleet Accident Rates:
Cirrus: 0.85%
Late-Model 172: 1.72%

However, here's an interesting point: The C172 is used for instruction, while
the Cirrus is not. The NTSB lists none of the 20 Cirrus accidents as occurring
during instruction, while 68 of the late-model 172s are so listed.

If you eliminate the instruction accidents from the late-model 172 accidents,
the 172 rate drops to 0.59% *if* you assume the same fleet size. However, to be
an honest comparison, the fleet size would have to address only those aircraft
flown for personal pleasure or business...an almost impossible task. In any
case, the fleet rate would be higher.

From this data, I don't think the Cirrus rate stands out excessively.

Ron Wanttaja