Is that figure per model or per actual airplane? If the latter, 0.01% seems close to something I'd expect to actually see just by chance.
If I understand correctly, that's the probability for 2 crashes within any span of 150 kiloflights. I'm curious if it makes sense to ask about the first span of 150.
It's likelihood per 150k flights per model (although likelihood per 150k flights per individual plane would give the same answer, it's just a weirder question).
The assumption is that for the average plane all accidents happen independently from one another. Under such an assumption, the probability for any span of 150k flights is exactly the same as the probability for the first span of 150k. So it would not change the answer.
If you roll a die a 1000 times, the odds of landing on a 6 on roll 999 is the same as it landing on a 6 the very first roll.
If I understand correctly, that's the probability for 2 crashes within any span of 150 kiloflights. I'm curious if it makes sense to ask about the first span of 150.