MERGED: Air Asia Turnback Perth 25 Jun 17

[misd-agin]

Originally Posted by CurtainTwitcher

Its covered in the EASA ETOPS document.

Page 34/65 -

This test must be run with the high speed and low speed main engine rotors unbalanced to generate at least 90 percent of the applicant’s recommended maintenance vibration levels. Additionally, for engines with three main engine rotors, the intermediate speed rotor must be unbalanced to generate at least 90 percent of the applicant’s recommended acceptance vibration level.

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I've reached vibration limits and they weren't noticeable. Ninty percent would be a lower figure.

So what level is the pylon and wing certified to when the entire plane is shaking?

How long is the good engine certified to operate when exposed to level X vibration? What level are they tested to, especially for 90+ minutes.

I don't know the answers. I doubt 1/100, perhaps 1/1000, or 1/10,000 pilots know the answers. Absent that knowledge I'd do whatever I could do reduce the vibrations and land ASAP. We don't operate with " I think it will stay together" as a hope. Absent knowledge, or if there's significant doubt about the safety of the aircraft, landing and solving the trouble shooting, or investigation, on the ground is the most prudent course of action.

And none of this addresses the requirement to land at the nearest suitable after the lose of an engine.