Cirrus... is it time for certification review?

"Morgans" wrote in message
...
Clue - Look at fleet size, then adjust for that, and come back with some
more meaningful statistics.

The fleet size isn't nearly as relevant as total flight hours for the flight
over a span of time. And yes, I agree that the data is missing. However,
none of you have provided alternate data to support the claim that the
Cirrus is actually worse. And at first glance, the total number of Cirrus
accidents is MUCH lower than for Cessna accidents, which is exactly what one
would expect given the difference in fleet sizes.

Clue: when you are making accusations, the burden of proof is on YOU. If
you're going to claim that the accident rate is abnormally high, you need to
provide data to support that claim. Suggesting that the defense has
insufficient data isn't meaningful.

Pete

Morgans wrote:
"Peter Duniho" wrote

A quick NTSB database search shows in the last six months 4 accidents (2
fatal) involving a Cirrus SR20, and 52 (5 fatal) involving a Cessna 172. The
SR22 was involved in 7 accidents (2 fatal), while the Cessna 182 was involved
in 36 (6 fatal).

Clue - Look at fleet size, then adjust for that, and come back with some more
meaningful statistics.

How many bazillion C172's are there out there, vs. Cirrus?

One thing these figures seem to say is that 50% of SR20 accidents are
fatal, but only 10% of 172 accidents are. It is only a bit better if
you compare both Cirrus and Cessna types. The parachute should make
Cirrus accidents more survivable, not less.


John Halpenny

On 31 Oct 2006 17:28:21 -0800, "John Halpenny"
wrote in .com:

One thing these figures seem to say is that 50% of SR20 accidents are
fatal, but only 10% of 172 accidents are. It is only a bit better if
you compare both Cirrus and Cessna types. The parachute should make
Cirrus accidents more survivable, not less.

What's the SR20's stall speed compared to the C-172? The kinetic
energy expended in a mishap increases exponentially with the square of
the velocity.

"John Halpenny" wrote in message
oups.com...
One thing these figures seem to say is that 50% of SR20 accidents are
fatal, but only 10% of 172 accidents are.

As I pointed out previously, there aren't enough SR20 accidents (or even
SR20 and SR22 combined) to make any valid statistical conclusions. The
statistical error on the sample size exceeds the number of samples.

Pete

Recently, Peter Duniho posted:

A quick NTSB database search shows in the last six months 4 accidents
(2 fatal) involving a Cirrus SR20, and 52 (5 fatal) involving a
Cessna 172. The SR22 was involved in 7 accidents (2 fatal), while the
Cessna 182 was involved in 36 (6 fatal).

One might say that the fatal accident rate seems disproportionate
(50% of the SR20, 25% for the SR22 versus 10% for the 172 and 20% for
the 182), but at the sample sizes present, there's absolutely no
reasonable way to draw any valid statistical conclusion (and note
that for the SR22 and the 182, the rates are actually similar).

The fact is, none of these airplanes are actually involved in fatal
accidents all that often, and the absolute numbers for overall
accidents are significantly lower for the Cirrus types than for
comparable Cessna types (of course, with a presumably much smaller
fleet size, that's to be expected, even without accounting for
differences in utilization).

Without the total fleet numbers, it is difficult to establish a
proportionate accident rate, but there is face validity to the notion that
the Cessna accident rate is far lower than Cirrus', given other methods of
comparison such as time flown per type or number of TOs & Landings.
Looking only at the type of accidents, one may conclude that pilot error
is the primary cause for either make of plane.

Neil




So, it seems to me that before we start throwing around statements
like "the problem is with the pilots, not the airplanes", it ought to
be established that there *is* a problem in the first place.

Pete

On Fri, 27 Oct 2006 18:26:33 -0400, "Kyle Boatright"
wrote:


"john smith" wrote in message
...
With the recent spate of Cirrus accidents, the question arises, "Is it
time for a special certification review?"


Any aircraft has a baseline accident rate. I think the Cirrus has a higher
accident rate because a handful of pilots get themselves into a mindset
where they are willing to enter conditions they would have not entered
without the big round "insurance policy". Often they get away with pushing
things. Sometimes they don't, and those accidents are the ones that are
taking the Cirrus accident rate to higher than predicted levels.

The problem is with the pilots, not the airplanes.

I agree.

This discussion has come up at least twice a year since the SR-20 and
22 came out.

The SR-22 is a capable airplane. It has the BRS for "just in case", it
has the weeping wing deice for "just in case". It's not for know
icing, but just in case, it has the simple (er) set of engine and prop
controls, and it has fixed gear. BUT it has high wing loading. A
fair amount higher than most fixed gear pilots are used to and
noticeable heavier than a Bo. SR-22 loading is about 23.5 while the Bo
is on the order as about the same as a Cherokee at 17.2. The Bo wing
loading covers a wide rage from about 16 to 19# per sq ft. It's one
whale of a lot slipperier though than the Cherokee though.
This is almost 32% heavier loading compared to the Cherokee and the
lighter Bonanzas and Debonairs. That is not to be taken lightly and
there is no pun intended. Over a 30% change in wing loading is a
serious change particularly for low time pilots.

I thought I'd take the easy way out and do a quick search instead of
calculating a bunch of wing loadings. The first thing that came up
was: http://www.aviation-pilots.com/construct/thread41.html
Then I noted who did the calculations. Careful what you say as it's
sometimes surprising as to where it shows up. :-))

At any rate, the SR-22 has all these whiz bang safety features AND
it's fixed gear, but it has the performance of a Bonanza with up to
30% heavier wing loading. The safety features are great, but here we
have an airplane that is meant for, or should be meant for experienced
pilots used to high performance be it fixed or retract gear.

Put all these features in a plane and then put the typical pilot with
a fixed gear mentality behind the yoke and it could be a recipe for
disaster. I mean no disrespect to fixed gear pilots. The typical fixed
gear pilot moving to the SR-22 would be akin to me moving to a TBM-700
or 850 One is a pilot with a 130 MPH mind moving to a 200 MPH airplane
while I'd be the pilot with a 200 MPH mind moving to a 360 MPH
airplane. OTOH I do have at least a little experience with faster
planes with much higher wing loading, but not enough to be safe
though.

My point is that even with all the training provided and *required*
the pilots *appear* "to me" to be flying a 200 MPH high performance
airplane as if it were a 130 MPH airplane. As a purely personal
opinion, I think they should forget it has a fixed gear and fly it as
if it were a retract.

Actually I think the retract has an advantage. The SR-22 is slippery
with a high wing loading. In a Bonanza if you get into trouble they
tell you to put the gear down and forget the doors. When the gear goes
down even at pattern speed it feels like some one put the brakes on
although the brakes with those tires don't have that much authority on
the runway. :-))

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

In article ,
"Roger (K8RI)" wrote:

In a Bonanza if you get into trouble they
tell you to put the gear down and forget the doors. When the gear goes
down even at pattern speed it feels like some one put the brakes on
although the brakes with those tires don't have that much authority on
the runway. :-))

The best way to slow a retract down is to put the gear down in the air, and
pick it up again in the flare. :-)

On Sat, 28 Oct 2006 10:06:04 -0400, Roy Smith wrote:

In article ,
"Roger (K8RI)" wrote:

In a Bonanza if you get into trouble they
tell you to put the gear down and forget the doors. When the gear goes
down even at pattern speed it feels like some one put the brakes on
although the brakes with those tires don't have that much authority on
the runway. :-))

The best way to slow a retract down is to put the gear down in the air, and
pick it up again in the flare. :-)

I know it works in the air, but I'd as soon pass on trying the other
part:-)) A few years back we had a Mooney come in gear up. He said
it collapsed, but I think it collapsed trying to jack the airplane
back up:-)) At any rate that plane skidded about 2500 feed down the
runway before sliding off into the grass where it quickly stopped. I
don't normally use that much runway without ever touching the brakes.
BTW it was their first flight after the annual.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

"john smith" wrote in

With the recent spate of Cirrus accidents, the question arises, "Is it
time for a special certification review?"

Absolutely. Spending millions of dollars is justified whenever any idiot
whines that there's an issue that can be resolved by political action.

Answer your own question.

moo

john smith wrote:
With the recent spate of Cirrus accidents, the question arises, "Is it
time for a special certification review?"

For an unrelated project, I downloaded the FAA aircraft registration
database a couple of weeks ago. (Available at:
http://www.faa.gov/licenses_certific...raft_download/ )
I just did a couple of quick queries on it that might help answer the
question of what the Cirrus fleet size is.

Total Cirrus Design SR-20 entries in the master file: 597
Total Cirrus Design SR-22 entries in the master file: 2022

SR-20 entries in master file, listed by airworthiness date:

39 (blank)
1 1981
1 1997
5 1999
78 2000
46 2001
84 2002
96 2003
78 2004
86 2005
83 2006

If you assume that each aircraft went into service the year of its
airworthiness date, you can get the fleet size by year:

End Fleet
of size
1997 2
1999 7
2000 85
2001 131
2002 215
2003 311
2004 389
2005 475
2006 558 (through early October)

SR-22 entries in master file, listed by airworthiness date:

174 (blank)
121 2001
262 2002
304 2003
431 2004
442 2005
288 2006

Fleet size by year:

End Fleet
of size
2001 121
2002 383
2003 687
2004 1118
2005 1560
2006 1848 (through early October)

As a comparison, I did the same queries for the Cessna 172, including
the models 172, 172[ABCDEFGHIJKLMNPQRS], 172RG, P172D, R172[EGHJK],
T172, and CE-172-R172. Because this covers a much longer period of
time, some of the assumptions above are not as likely to be valid.

Total Cessna 172 entries in the master file: 26697

Cessna 172 entries in master file, listed by airworthiness date:

1825 (blank)
13 (garbled)
79 1955
780 1956
540 1957
447 1958
517 1959
494 1960
457 1961
448 1962
608 1963
782 1964
901 1965
909 1966
507 1967
765 1968
721 1969
438 1970
463 1971
625 1972
979 1973
1065 1974
1202 1975
1387 1976
1430 1977
1289 1978
1294 1979
880 1980
725 1981
248 1982
163 1983
159 1984
157 1985
97 1986
23 1987
27 1988
41 1989
42 1990
21 1991
38 1992
49 1993
41 1994
48 1995
48 1996
228 1997
344 1998
381 1999
385 2000
295 2001
291 2002
277 2003
216 2004
312 2005
196 2006

Fleet size by year:

End Fleet
of size
1955 79
1956 859
1957 1399
1958 1846
1959 2363
1960 2857
1961 3314
1962 3762
1963 4370
1964 5152
1965 6053
1966 6962
1967 7469
1968 8234
1969 8955
1970 9393
1971 9856
1972 10481
1973 11460
1974 12525
1975 13727
1976 15114
1977 16544
1978 17833
1979 19127
1980 20007
1981 20732
1982 20980
1983 21143
1984 21302
1985 21459
1986 21556
1987 21579
1988 21606
1989 21647
1990 21689
1991 21710
1992 21748
1993 21797
1994 21838
1995 21886
1996 21934
1997 22162
1998 22506
1999 22887
2000 23272
2001 23567
2002 23858
2003 24135
2004 24351
2005 24663
2006 24859 (through early October)

Matt Roberds