Originally Posted by
DaveReidUK
Leaving aside the oxymoron inherent in that statement, the suggestion that
is simplistic in the extreme, being based on the assumption that if a blade is going to let go it will do so the first time N1 reaches a certain value and not on some subsequent occasion.
It's particularly irrelevant in this case, given that the NTSB is already reporting indications of metal fatigue at the blade root.
"Last year, the engine maker and the Federal Aviation Administration instructed airlines to make ultrasonic inspections of the fan blades of engines like those on the Southwest jet. The FAA said the move was prompted by a report of a fan blade failing and hurling debris. A Southwest spokeswoman said the engine that failed Tuesday was not covered by that directive, but the airline announced it would speed up ultrasonic inspections of fan blades of its CFM56-series engines anyway.".
https://www.newsday.com/news/new-yor...tim-1.18129205