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Old July 6th 03, 05:51 AM
Marten Kemp
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Ken Hornstein wrote:

In article ,
Marten Kemp wrote:
Dan Luke wrote:
You believe this in spite of the fact that the fatal accident rate is 700%
higher for personal flying than for driving? Doesn't that seem like
something you might want to think about a little more?
C172RG at BFM

Sir, can you substantiate that amazing assertion?
Citations, websites, etc?

The statistics aren't easy to compare. But ...

From the National Highway Transportation Safety Administration's report,
"2001 Annunal Assessment Of Motor Vehicle Crashes", which can be found
at the following URL:

If you look at page 30, you can see a summary (based on year) of the
fatalities per 100 million vehicular miles travelled (VMT). For the
year 2001, passenger cars have 1.28 fatalities per 100M VMT, and
motorcycles have 33.38 fatalities per 100M VMT.

Now, the wrinkle here is that while automotive statistics are reported
in miles travelled, general aviation statistics are reported in hours
flown. For our 2001 aviation statistics, you can view them in the
Nall Report, a copy of which you can find at the following URL:

Page 1 shows for 2001, there were 298 fatal accidents and 535 fatalities
for 26.2 million hours flown. The highway data is based on fatalities,
not fatal accidents, so let's use the latter figure, which gives us
2.042 fatalities per 100,000 hours flown.

So, how do we compare the two sets of data? One very simplistic way is
to pretend that everyone drives at 55 MPH, which would make automotive
statistics 1.28 fatalities per 1.82 million hours driven, or .703
fatalities per million hours driven. If you assume a slower driving
speed, the fatality rate per hour goes down, and if you assume a faster
one, it goes up. If you stick with 55 MPH, then you end up with a 29x
more times of being involved in a fatal accident with flying versus

If you compare motorcycles to aviation, 55 MPH gives you 18.3 fatalities
per million hours driven, and 1.83 fatalities per 100,000 hours drive,
which is relatively close to the statistics for aviation fatalities.

This is, of course, a very simplistic view of the accident data, and
there are lots of questions about how total hours are estimated, the
data is collected, etc etc. And I would advise anyone who was curious
about this to examine the reports themselves and draw their own
conclusions. (And it would be prudent to bring up the old Mark Twain
quote about liars, damned liars, and statisticians). But this can give
you an idea where the often-quoted statistics about GA being more
dangerous than driving, and approximately as dangerous as riding a
motorcycle, come from.

Personally, I believe that GA is definately more dangerous than
driving, but that the majority of the risk factors in GA are under the
control of the pilot. Thus, a knowledgable pilot who makes good
decisions is probably safer than the average person in a car, since in
a car (and especially in a motorcycle) you're more at the mercy of
other people. But even though every pilot receives a ton more training
than the average driver, flying is still in general more dangerous than
driving, which tells me it's important to never forget the importance
of good judgement.


Very well, thank you all. I seem to have been operating
under a mistaken impression. {That grinding noise you hear
is my internal assumptions database rearranging itself}

-- Marten Kemp