Originally Posted by
englishal
I bet you could prove that IR'd pilots have a higher fatality rate in IMC conditions than an IMC rated pilot for example. I base this on the fact that more IR'd pilots have been killed in CFIT type accidents than IMCr'd pilots. IN fact saying this, you could prove (via stats) that the IMCr'd pilot is in fact the most safe pilot - less have been killed in CFIT accidents than IR'd pilots, and less have been killed in weather related accidents than vanilla PPL's...Therfore there must be a safety case for the IMCr?
If you choose non-comparable populations you can prove anything (eg mice run faster than cats (sample is live mice and dead cats)). If you choose comparable populations (eg pilots flying piston aircraft in the UK with PPL, IMCr, IR ) you will find the UK has no exposure data (we can not establish how many flights, hours, in what conditions, or even how many people are in each population). As such, it is almost impossible to make a statistically valid comment on the relative safety of PPL, IMCr and 'PPLIR' operations. Additionally, the level of accidents in the IMCr and IR population are so low that it would take decades (over which time technology shift would be very relevant) to build a valid sample.
To the best of my knowledge, European aviation safety statistics are reported on a consistent basis (accidents in the population/ 100k estimated hours of the population). However, as LH2 points out, the nature of the activity could be highly skewed. Within the UK the different elements of GA have very different accident rates.