"MMO" wrote in message ...
Getting back to the original question...

Twin-engine turbine powered commercial aeroplanes have an "in-flight
propulsion system shutdown rate" of approx 0.02 per 1000 hours.
(Source: ICAO ETOPS approval papers)

You will have to work the rest out. That's all I can help you with.

That's just the minimum standard that 180-minute ETOPS certified
aircraft need to meet. In actual practice, engines exceed this
standard.

Ace