Chris Reed wrote:
It also means that over a 40 year soaring career your probability of
being in a fatal accident is around 1 in 50, or 2% - assuming you fly
the average annual amount of hours over the entire period.

9B


No, it doesn't. The risk isn't cumulative, it's 1:2,000 each year you
fly.
True, but 9B said "over 40 year soaring career".

I can guarantee that if you have a fatal accident in year 1, your risk
of repeating it in years 2-40 is 0%.
True, but irrelevant. I also calculate the risk over a 40 year period as
being 2%, assuming the 1 in 2000 chance/year. YMMV.

Chance of not being in an accident each year = (1 - 0.0005) = 0.9995
For 40 years, chance = 0.9995^40 = 0.98

That's 98% chance of not being in an accident. Lots of assumptions, so
maybe not too instructive.
For 40 years, 1 in 8000 gets it down to 99.5% of not being in an accident.

--
Eric Greenwell - Washington State, USA (netto to net to email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz