Pilots with weakening vision - please install Powerflarm

On Friday, July 12, 2013 8:50:50 AM UTC-6, jfitch wrote:
I am surprised so far no one has noticed a serious flaw in my statistical argument. Didn't think of it myself until yesterday. There were 6 incidents of glider-to-glider mid air in the last 20 years, of 676 incidents involving gliders. That is less than 1%. However, it takes two to tango - so that accounts for 12 gliders involved in mid airs. That makes the probability for an individual glider historically greater than 1%, but a bit less than 2%, that an accident will involve a mid air with another glider. And of course the absolute probability on a particular flight nearly vanishingly small: if there are 2500 flights per reported accident (a reasonable guess), P = 8 x 10^-6.

Figure 130,000 - 150,000 glider flights per year.