Originally Posted by SAT Lawyer
The heavily second-guessed BA flight from LAX-LHR excepted, I can't think of many 747 flights with passengers on board that attempted to continue to a final destination following a single engine failure. And even in that example, the flight was diverted albeit to an airport in the same country as the intended destination airport.
it was, but it did actually have enough fuel to continue the flight to LHR - the pilots were unsure if it did so rightly declared a fuel emergency. And one example is all that is needed to prove it can do it - just as one incident with a double IFSD on a twin would raise a lot of eyebrows.
More fundamentally, the statistical likelihood of an engine failure causing a delay-inducing diversion on any modern jet is so rare that it probably shouldn't even factor into any equation from a delay standpoint, especially when considering the infinitely greater chances of being delayed or even diverted for other aggregate reasons such as weather, security, other mechanical problems, etc.
Well the official acceptable failure rate for engines IFSD is 1 x10-9 That's what the rule-making and certification standards are intended to achieve. Less than that, and the safety case may have to be re-examined. At the same time, if you read the techie boards, IFSD do probably occur about as commonly as security related diversions. But most of them happen on short-haul a/c where the don't get much press coverage, as it's generally an easy divert.