Cirrus... is it time for certification review?

Ron Wanttaja wrote:
On Sat, 28 Oct 2006 17:10:46 GMT, wrote:
If you assume that each aircraft went into service the year of its
airworthiness date, you can get the fleet size by year:

Actually, that date (fields 229-236) relates more to the current owner,
than the manufacture date.

That column is labeled as "certificate issue date" in the FAA database
and I agree that it changes more often. That's not what I used, though -
I used the "airworthiness date", positions 266-273. I know of a couple
of aircraft that have changed hands a few times, and the certificate
issue date usually tracks the latest change of ownership, but the
airworthiness date usually corresponds to the original year of
manufacture.

Fields 52-55 contain the official "Year Manufactured."

Yep, it's still there. I just didn't think of using it when I compiled
the data the first time.

Nice idea, though...re-run your query using the Year Manufactured, and
let's have another look at the data.

Here it is, noted with "YOM". I have included the data from my first
post, noted with "A/W", for comparison.

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 and by year
of manufactu

A/W YOM
blank 39 39
1981 1 1
1995 0 1
1997 1 0
1998 0 3
1999 5 8
2000 78 78
2001 46 45
2002 84 84
2003 96 94
2004 78 77
2005 86 87
2006 83 80

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

End Fleet size by
of A/W YOM
1997 2 2
1998 2 5
1999 7 13
2000 85 91
2001 131 136
2002 215 220
2003 311 314
2004 389 391
2005 475 478
2006 558 558 (through early October)

SR-22 entries in master file, listed by airworthiness date and by year
of manufactu

A/W YOM
blank 174 175
2001 121 126
2002 262 267
2003 304 307
2004 431 430
2005 442 445
2006 288 272

Fleet size by year:

End Fleet size by
of A/W YOM
2001 121 126
2002 383 393
2003 687 700
2004 1118 1130
2005 1560 1575
2006 1848 1847 (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 and by
year of manufactu

A/W YOM
blank 1825 1040
garbled 13 57
1955 79 107
1956 780 956
1957 540 583
1958 447 543
1959 517 566
1960 494 581
1961 457 493
1962 448 509
1963 608 678
1964 782 862
1965 901 1010
1966 909 1069
1967 507 569
1968 765 912
1969 721 708
1970 438 483
1971 463 476
1972 625 658
1973 979 1023
1974 1065 1149
1975 1202 1313
1976 1387 1468
1977 1430 1443
1978 1289 1368
1979 1294 1257
1980 880 811
1981 725 691
1982 248 222
1983 163 87
1984 159 143
1985 157 180
1986 97 81
1987 23 0
1988 27 3
1989 41 0
1990 42 0
1991 21 0
1992 38 0
1993 49 0
1994 41 1
1995 48 0
1996 48 1
1997 228 191
1998 344 293
1999 381 355
2000 385 353
2001 295 267
2002 291 248
2003 277 244
2004 216 181
2005 312 292
2006 196 170

Fleet size by year:

End Fleet size by
of A/W YOM
1955 79 107
1956 859 1063
1957 1399 1646
1958 1846 2189
1959 2363 2755
1960 2857 3336
1961 3314 3829
1962 3762 4338
1963 4370 5016
1964 5152 5878
1965 6053 6888
1966 6962 7957
1967 7469 8526
1968 8234 9438
1969 8955 10146
1970 9393 10629
1971 9856 11105
1972 10481 11763
1973 11460 12786
1974 12525 13935
1975 13727 15248
1976 15114 16716
1977 16544 18159
1978 17833 19527
1979 19127 20784
1980 20007 21595
1981 20732 22286
1982 20980 22508
1983 21143 22595
1984 21302 22738
1985 21459 22918
1986 21556 22999
1987 21579 22999
1988 21606 23002
1989 21647 23002
1990 21689 23002
1991 21710 23002
1992 21748 23002
1993 21797 23002
1994 21838 23003
1995 21886 23003
1996 21934 23004
1997 22162 23195
1998 22506 23488
1999 22887 23843
2000 23272 24196
2001 23567 24463
2002 23858 24711
2003 24135 24955
2004 24351 25136
2005 24663 25428
2006 24859 25598 (through early October)

John Smith posted the following:

Accidents and incidents (from theFAA and NTSB databases)
1998 2000 2001 2002 2003 2004 2005 2006
SR20 1 0 2 3 0 1 2 7
SR22 - - 2 2 3 8 12 15

Using that data along with the fleet size data:

SR-20

Fleet % accidents
End size by Acci- by
of A/W YOM dents A/W YOM
1997 2 2 0 0 0
1998 2 5 1 50 20
1999 7 13 0 0 0
2000 85 91 0 0 0
2001 131 136 2 1.5 1.5
2002 215 220 3 1.4 1.3
2003 311 314 0 0 0
2004 389 391 1 0.26 0.26
2005 475 478 2 0.42 0.42
2006 558 558 7 1.3 1.3 (through early October)

SR-22

Fleet % accidents
End size by Acci- by
of A/W YOM dents A/W YOM
2001 121 126 2 1.7 1.6
2002 383 393 2 0.52 0.51
2003 687 700 3 0.44 0.43
2004 1118 1130 8 0.72 0.71
2005 1560 1575 12 0.77 0.76
2006 1848 1847 15 0.81 0.81 (through early October)

Combined SR-20 and SR-22

Fleet % accidents
End size by Acci- by
of A/W YOM dents A/W YOM
1997 2 2 0 0 0
1998 2 5 1 50 20
1999 7 13 0 0 0
2000 85 91 0 0 0
2001 252 262 4 1.6 1.5
2002 598 613 5 0.84 0.82
2003 998 1014 3 0.30 0.30
2004 1507 1521 9 0.59 0.59
2005 2035 2053 14 0.69 0.68
2006 2406 2405 21 0.87 0.87 (through early October)

Finally, taking the combined SR-20 and SR-22 data for 2001-2006, and
applying it to the 172 fleet size, we get an approximate number of
accidents and incidents that would be expected from the 172 fleet, if
the 172 and SR-20/22 have about the same safety record:

Cessna 172

Fleet Expected number of
End size by accidents by
of A/W YOM A/W YOM
2001 23567 24463 374 373
2002 23858 24711 199 202
2003 24135 24955 72.6 73.8
2004 24351 25136 145 149
2005 24663 25428 170 173
2006 24859 25598 217 224 (through early October)

Matt Roberds

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

In article ,
Ron Wanttaja wrote:
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.

How does the Cirrus rate compare to the late model 182 accident
rate, or the late model Bonanza accident rate? Those are more
likely to be used for travel, like most Cirrus planes.

John
--
John Clear - http://www.clear-prop.org/

"Dave Stadt"
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).

Apples and oranges. The 182 fleet is many times larger than the SR22
fleet. And the 172 fleet is near infinite compared to the Cirrus fleet.
The numbers look pretty bad for Cirrus.

Did you adjust for the kind of flying done by each? No, you didn't.

The flights all involve an equal number of takeoffs and landings only some
are more successfull in the landing department than others.

Unless you wish to redefine "flight" , no, they don't. Are circuits
"flights"?

moo

On Sun, 29 Oct 2006 19:33:40 +0000 (UTC), (John
Clear) wrote:

In article ,
Ron Wanttaja wrote:
Average ANNUAL Fleet Accident Rates:
Cirrus: 0.85%
Late-Model 172: 1.72%

How does the Cirrus rate compare to the late model 182 accident
rate, or the late model Bonanza accident rate? Those are more
likely to be used for travel, like most Cirrus planes.

Good suggestion. I ran the new production 182 figures, as it's fixed gear like
the Cirrus. Average of 1154 aircraft during the 2002-2004 period, 26 accidents,
average fleet accident rate of 0.75% per year. Slightly better than the Cirrus,
but still pretty close.

Ron Wanttaja

"Happy Dog" wrote in message
m...
"Dave Stadt"
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).

Apples and oranges. The 182 fleet is many times larger than the SR22
fleet. And the 172 fleet is near infinite compared to the Cirrus fleet.
The numbers look pretty bad for Cirrus.

Did you adjust for the kind of flying done by each? No, you didn't.

The flights all involve an equal number of takeoffs and landings only
some are more successfull in the landing department than others.

Unless you wish to redefine "flight" , no, they don't. Are circuits
"flights"?

moo

I suspect so. Unless one just motors around on the ground in a big
rectangle.

"Dave Stadt" wrote
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).

Apples and oranges. The 182 fleet is many times larger than the SR22
fleet. And the 172 fleet is near infinite compared to the Cirrus
fleet. The numbers look pretty bad for Cirrus.

Did you adjust for the kind of flying done by each? No, you didn't.

The flights all involve an equal number of takeoffs and landings only
some are more successfull in the landing department than others.

Unless you wish to redefine "flight" , no, they don't. Are circuits
"flights"?

I suspect so. Unless one just motors around on the ground in a big
rectangle.

Which would be redefining "circuits". So the flights don't "all involve an
equal number of takeoffs and landings". Your desire to engage in semantics
aside, Cirruses are not training aircraft. So a direct comparison of
"numbers" is really telling us enough about the safety of each plane.
Either way.

moo

Ron,

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


Dick Collins did the same analysis for new 182s and Cirrus. Same
result.

--
Thomas Borchert (EDDH)

Which would be redefining "circuits". So the flights don't "all involve an
equal number of takeoffs and landings".

How so? Is there an accumulation of aircraft in the sky (or on the
ground) when one does circuits? When I do them, the number of takeoffs
does in fact equal the number of landings. I just do more of them.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

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


Dick Collins did the same analysis for new 182s and Cirrus. Same
result.


It does seem like the parachute, an occasional a celebrity, amd the
inconsistancy of small samples have simply increased the hype factor.

Peter