I have seen it claimed by a manufacturer of airliners, along with the media at large and many pilots, that flying is safer than driving.

Maybe they can say so because the two modes are not directly comparable, so it's hard to prove they're wrong. But I went and messed with some statistics, hoping to come to a conclusion myself, and I have to conclude that flying is not safer than driving.

I take no joy in this conclusion, because I love to fly. (I'm a brand new private pilot with about 70 hours. Just passed my flight test two days ago.)

But when I ran some numbers, I was forced to conclude that however you measure it,* flying is not safer than driving. This is especially true with general aviation. It important to remember this, not kid ourselves, and never get complacent about saftey.

The details for those who want more

The reason for the little * above is that there is one exception that the airlines/airliner manufacturers use that I consider to be statistical cheating: They measure fatalities/accidents/etc. per million passenger miles, a passenger mile being the multiplication of miles x passengers. Basically, they get 100-400 times the credit for each safe landing based on how many people are on board. The problem with this, from a statistical point of view, is that passenger miles are not accidents drivers. Hours, miles flown (i.e. airplane miles, not passenger miles), takeoffs, landing, etc. are all things that might drive accidents, but not how many people are on board. Anyway, all this is neither here nor there, because in general aviation, even using the misleading accidents per million passenger miles measurement would not make flying safer than driving. It only does so for the airlines.

Here are the conclusions I reached based on three ways of measuring it. I can provide the underlying data and references to anyone who may be interested:

When I considered fatalities per 100 thousand hours flown or driven (using all USA numbers), I got 2.1 for general aviation, 1.25 for air carriers, and around 0.06 for motor vehicles (i.e. driving). (I did have to make an assumption to try to convert driving miles to driving hours, since only miles are known. For all reasonable values, the order remains the same, i.e. with driving having the least fatalities.) This makes general aviation some 35 times more fatal than driving using this measure, and airlines 21 times more fatal.

When I considered fatalities per 100 million vehicle or aircraft miles, I got 23.32 for general aviation, 3.06 for air carriers, and 1.53 for motor vehicles. (Again, some assumptions were necessary to make things comparable, in this case an assumption about average velocity to convert general aviation hours to miles, since miles flown are not known in GA. However, as was the case in my assumption above, for all reasonable assumed values the order does not change: GA, then air carriers, then driving.) Using this measure general aviation is only 15 times more fatal than driving, and the airlines only twice as fatal as driving. But driving still comes out on top for safety (or at least survivability).

Only when you consider the funky fatalities per million passenger miles statistic do you get aviation suddenly looking better: GA was 0.05 over the period I examined, motor vehicles was 0.01, and air carriers was 0.0003. Here is where the airlines shine, when you add in a figure (number of people on board) that logically has no correlation with accidents.

So, as sorry as I am to disillusion anyone (okay, I'm not sorry; I like myth-busting), I think we should acknowledge that aviation, while not particularly hazardous, is still more dangerous than driving. When you think back on what it took for you to learn to fly, find the airport, land in a cross-wind, recover from a bounce, do a forced approach, etc., this should make intuitive sense anyway.

Let's continue to fly and love it, but let's not kid ourselves by minimizing the risks. They are real.

Your thoughts?

Chad Conrad
Calgary, Alberta
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