Each year, the annual Safety Issue of Cirrus Pilot reports various statistics about the
fatal accident rate in the fleet of Cirrus aircraft. As the COPA de facto accident historian, I often respond to
queries about Cirrus accidents and provide factual data for the readers to draw
their own conclusions.
These trends
have been somewhat stable since the Cirrus fleet exceeded 3,000 aircraft. There
continues to be fatal accidents, as well as the debate about Cirrus safety; and
COPA continues to promote safety in everything we do.
But what
continues to amaze me is that COPA members have an astoundingly better accident
rate. Those members who participate in our safety programs are approximately
four times less likely to have a fatal accident than those who do not.
Cirrus Fatal
Accident Rates
Rates of fatal
accidents can be computed in many different ways. Using NTSB reports, we know
the number of fatal accidents by month. By the SR2X fleet statistics gathered
from the GAMA quarterly production reports, we can calculate the number of
fatal accidents per airplane. With the flying hours gathered by Cirrus Aircraft
from their warranty and AD compliance reports, we can calculate the number of
fatal accidents per 100,000 flight hours.
Fatal Accidents
by Quarter
Plotting the
frequency of Cirrus fatal accidents by quarter reveals a sporadic pattern in
Figure 1, with some quarters having no accidents and other quarters having
several. There is a general upward trend, which increased in late 2006 through
early 2008, that might be expected as the fleet size increased. Emphasizing the
large portion of Cirrus fatal accidents that involve bad weather, the darker
bars represent the fall and winter months from October to March. Clearly, there
are more accidents in those months with bad weather than the spring and summer
months.
FIGURE 1: Number of fatal Cirrus accidents by
quarter since production of the SR20 began in mid-1999. Note that the
dark bars represent accidents in the fall and winter months, October to
March. About two-thirds of the fatal accidents (35 of 55), occur in the
half of the year with shorter days and winter weather.
Fatal Accidents by Size of Fleet
Calculating the number of fatal accidents against the growth in the
number of SR2X aircraft produced (see Figure 2), reveals an upward
trend, meaning more of the fleet becomes involved in a fatal accident
as the fleet grows.
FIGURE 2: Total number of SR2X fatal accidents per
1,000 aircraft produced since the certification of the SR20 in mid1999.
The upward trend shows that the fraction of the fleet involved in a
fatal accident has been growing faster than the growth of the fleet.
The line slopes downward in periods when there were fewer accidents as
the fleet grew larger. We want this line to trend downward.
There have been several bad patches, each corresponding to fall/winter
months. In 2001, the first fatal accident caused the initial jump in
the curve. In 2002, there were three accidents when the fleet was still
small. Then in early 2003, two accidents occurred within a week of each
other (Hill City, Minn., and San Jose, Calif.) creating a significant
jump. Since 2004, there has been a general upward trend indicating more
of the fleet was involved in a fatal accident.
This upward trend is worrisome, especially as more of the fleet changes
hands due to sale of used airplanes without the provision of initial
factory transition training.
Fatal Accidents per 100,000 Flight Hours
The traditional method of comparing year-over-year trends in fatal
accidents is to calculate the number of accidents per 100,000 hours of
flying time. This better represents the greater activity of newer
airplanes compared with aged airplanes in the GA fleet. So too with
Cirrus airplanes, as the oldest SR20 airplanes are now 10 years old.
The FAA conducts an annual survey to determine flying time. The NTSB
accident reports provide the number of accidents each year. From that,
the NTSB publishes an accident rate per 100,000 hours of flying time.
FIGURE 3: Comparison of SR2X fatal accidents
per 100,000 hours of flying time with the GA fleet, using both 12 month
and 36 month trend lines. Note that when the accident rate was very
high in 2001 to 2003, per Figure 1 and 2, it can be seen that there
were only a few accidents (one to three per year) and the fleet was
small (less than 1,000 airplanes). In 2007, the rate dipped, but
because the fleet had grown to 3,700 airplanes flying 650,000 hours per
year, even though there were actually a larger number of accidents –
eight.
For example, in 2007, the GA fixed-wing fleet of about 260,000 aircraft
flew 23.8 million flight hours and had 284 fatal accidents for an
overall rate of 1.19 fatal accidents per 100,000 flight hours. This GA
accident rate has been slowly declining for the past decade (see Figure
3).
With the fleet hours provided by Cirrus Aircraft, we can estimate the
Cirrus SR2X flying time for each quarter based upon the production
numbers. Then, given the number of fatal accidents, we can calculate
the fatal accident rate.
Note that small variations can cause large fluctuations in these rates.
In Figure 3, the first accident in 2001 caused a huge jump, and the
spike in 2002 came from just three accidents in a fleet of about 600
airplanes that flew less than 100,000 hours. By comparison, the slight
rise in 2009 came from nine accidents.
With that in mind, let me offer four variations of the Cirrus fatal accident rate using different time scales:
- 1.69 fatal accidents per 100,000 hours since certification in mid-1999
- 1.74 fatal accidents per 100,000 hours in the past 36 months
- 1.83 fatal accidents per 100,000 hours in the past 12 months
- 1.90 fatal accidents per 100,000 hours in the first nine >months of 2009.
Therefore, one can say that the Cirrus fatal accident rate is between
1.69 and 1.90 per 100,000 hours depending on how much aggregation you
want to provide to stabilize the trends.
Comparing Cirrus Accident Rates to Other Fleets
We can now see that the Cirrus fatal accident rate is higher than the
overall general aviation rate of 1.19 fatal accidents per 100,000
flight hours.
But comparing Cirrus to the GA fleet is a tough comparison, because
general aviation includes multi-engine turboprops and turbojets flown
by two pilots. That redundancy and professionalism produces
significantly fewer fatal accidents. Backing out the flight hours for
those aircraft from the survey reduces flight time to about 14 million
flight hours. Backing out the number of fatal accidents in multi-engine
aircraft from the Nall report produces about 261 fatal accidents.
Thus, the single-engine piston accident rate is about 1.86 fatal accidents per
100,000 flight hours. The Cirrus rates of 1.69 and 1.90, depending on the time
scale, compares favorably with single-engine piston aircraft rate of 1.86.
But what about other competitive aircraft like Cessna, Beechcraft,
Mooney, Columbia, or Diamond? Unfortunately, none of those
manufacturers have revealed their fleet hours. The legacy manufacturers
have produced considerably more aircraft over a long time period, so
fleet comparisons may not be meaningful. For instance, the FAA survey
of GA activity reports airplanes less than five years old fly about 200
hours a year, while planes, 25 years or older, only fly 125 hours per
year.
As for fleet sizes, other new manufacturers have such small fleets in
comparison to Cirrus Aircraft, perhaps one-tenth to one-third of the
number of airplanes, that just a few accidents can cause a huge
fluctuation in their accident rates. So, until more information becomes
available, no meaningful comparison is possible.
Predicting Accident Rates
That’s history. What about the future? How many accidents do we expect?
As we start the fall and winter season, remember that most Cirrus
accidents happen in the months from October to March, in bad weather,
from pilot causes.
At the current three-year rate of 1.74 fatal accidents per 100,000
flight hours, expect about 10 more fatal accidents before next summer.
Even if the accident rate declines to 1.00, we can expect six more
fatal accidents by summer.
How can we change that? Actions by Cirrus pilots that demonstrate an
unparalleled commitment to safety as advocated by COPA will help. Reach
out to other Cirrus pilots who are not members of COPA will help. Take
action to break your own accident chain. Fly safe.
COPA Membership and Accident Rates
Finally, a reason to appreciate the dramatic safety record of COPA
members. In terms of airplanes, COPA members fly about 40 percent of
the airplanes (1,880 of 4,417) produced. In terms of pilots, we
speculate that COPA members represent about 44 percent of Cirrus pilots
(2,665 of approximately 6,000). Yet, in terms of accidents, COPA
members were involved in only 22 percent of the fatal accidents (12 of
55) – way less than the expected numbers (see Figure 4).
FIGURE 4: COPA member percentages of SR2X airplanes, Cirrus pilots and
fatal accidents. Each bar is 100% with the split between COPA members and
non-members centered. COPA members have a dramatically
lower number
of fatal accidents despite representing more than half of the pilot population
and SR2X airplanes in the fleet.
As a predictor of fatal accidents per airplane, a plane flown by a
nonmember of COPA is almost three times more likely to have a fatal
accident: COPA members had 12 accidents among 1,880 planes (1 in 157),
nonmembers had 43 in 2,553 (1 in 59). And in terms of fatal accidents
per pilot, non-members of COPA are also three times more likely to have
a fatal accident: COPA members had 12 accidents among 2,665 pilots (1
in 222), non-members had 43 in approximately 3,335 (1 in 78).
If you examine the COPA activities of those 12 fatal accident pilots,
you find several who were members with minimal involvement, who did not
participate in either the COPA discussion forums or the safety
programs. Pilots who do not participate in COPA safety activities are
about four times more likely to have a fatal accident.
Participate in COPA safety activities! Only you can break your accident chain of events.
