Originally Posted by
pax2908
was wondering if the certification process requires only one such successful test instead of a statistically significant number of blade release tests and/or recurrent such tests? ($$$)
Assuming it passes, the complete engine fan blade out test is only run once - the test is horribly expensive (it basically destroys the test engine, plus it's heavily instrumented with much of the instrumentation also effectively written off, plus all the 'normal' costs of doing an engine test). They often do rig tests - basically an isolated fan - to test out certain aspects to make sure it'll work when they do the whole engine test. The test is done at redline N1, which is normally considered to be the worst case condition.
The only time I know of where they repeated the test was on the original GE90 - although the blade was contained, the resultant vibrations caused a bunch of other stuff to fail (including the inlet coming off at the attachment flange). Although they tried to convince the Feds that they could show analytically that they'd fixed all the failures, the FAA made them repeat it. Scuttlebut was the cost of repeating the test was north of $40 million.
All that being said, I've not seen anything that says the fan blade was uncontained. Clearly the inlet structurally failed, but the why is unclear.