Quote Originally Posted by jiott;91231[COLOR=#333333
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Very likely John was saying it took that long to reach a very fine balance condition. I doubt he meant that there was major shaking for that long...[/COLOR]
That's exactly right, Jim. To try to further clarify... when you're looking at the vibration level sensed by the accelerometer, it is generally far more sensitive than what you can "feel" inside the airplane. I'm talking about not only minor, but also significant vibration levels at the engine in many instances. By significant I mean that they are worth reducing or eliminating, for all of the reasons that have been discussed.