Air AsiaX engine issues, plane shakes, pilot asks passengers to pray

[dagger]

http://www.cnn.com/2017/06/25/asia/air-asia-flight-turns-back-technical-issue/index.html

An engine issue followed by two hours of significant vibration, I imagine that would unnerve even experienced flyers.

 

[conehead]

Pretty severe...

[Boney]

Was it engine vibration? Was it a flight control flutter? Hope we hear the cause soon. 

[boestar]

That is indicative of an LP Compressor vibration, and a severe one at that.

[conehead]

I'm wondering if it would have been prudent to shut down that engine?

[boestar]

I would think that would be the preferred course of action.

 

[Seeker]

Why would anyone assume the engine was still running?  It sounds like a classic example of a contained loss of a fan blade.  The engine was almost certainly not running with the vibration coming from the unbalanced fan windmilling. 

The Captain failed miserably by telling the passengers to pray rather than explaining that the vibration from an unbalanced fan was within the design specifications for the structure of the pylon and that, although annoying, was not dangerous.  He could also have explained that the aircraft was easily capable of flying safely to an airport for landing and that the crew had practiced for this situation many times.  Of course I would not expect him to use those exact words but rather to simplify and use calm and reassuring words - telling the passengers to pray is not right.

[boestar]

Why do you assume he shut it down?  Shutting \down and engine in flight comes with penalties especially with ETOPS certification.  Reducing the thrust to idle is not considered an IFSD.  Some airlines will do anything to not lose ETOPS.

 

[Seeker]

19 hours ago, dagger said:

http://www.cnn.com/2017/06/25/asia/air-asia-flight-turns-back-technical-issue/index.html

An engine issue followed by two hours of significant vibration, I imagine that would unnerve even experienced flyers.

 

In this case, since the Captain told the passengers to pray, I wouldn't have been surprised to see very upset passengers.    With a proper explanation of the situation, a calm and reassuring PA and the correct words the passengers would have been fine.

[Seeker]

1 minute ago, boestar said:

Why do you assume he shut it down?  Shutting \down and engine in flight comes with penalties especially with ETOPS certification.  Reducing the thrust to idle is not considered an IFSD.  Some airlines will do anything to not lose ETOPS.

 

OK, maybe he didn't shut it down.  The vibes would have been outside of the allowable range and the QRH would have directed a shutdown but maybe he chose to keep it running and spare the company's ETOPS rating although the fact that he was telling the passengers to pray seems to indicate he had more pressing concerns.  In any case, windmilling or running at idle, the rest of my post stands - you don't tell the passengers to pray, you tell them everything is fine and they'll be landing safely (which is what happened!).

[GDR]

The Captain said things like "our survival depends on your co-operating" and to pray and that hopefully we'll all get there safely. This is a guy that is just building up the drama so that he looks like a hero when they land. Instead of trying to reassure the passengers he did exactly the opposite adding to the stress of everyone in the back including the crew. Unbelievably unprofessional.

[blues deville]

2 hours ago, GDR said:

Unbelievably unprofessional.

From the pilots I've viewed waiting for hotel pick up I'd also say "inexperienced". They're a pretty young group. 

[UpperDeck]

Hey!! Who knows.....maybe the power of combined prayer kept the port engine operational.

Or maybe there were simply " cultural differences"......we got there on a " wing and a prayer".

[DEFCON]

Assuming the engine was running, is it possible that something was damaged during the event that left the crew unable to shut it down?  

[boestar]

The engine may or may not have been running.  The rotating mass is large enough that it would shake like crazy if just windmilling.  if it had shed a blade that vibration would be very large.  Shutdown would be prudent and warranted but from the information we have we can only speculate as to what was actually done. I posed a possibility earlier as more of a devils advocate than anything else.

 

[Boney]

If engine was shut down and the windmilling fan was causing this vibration, then a change in speed and altitude should have been carried out. 

Hoping to see report soon. 

Cheers. 

[mo32a]

According to news reports he shut down the engine and then choose to return to Perth rather than land at the nearest suitable airport which was just off his starboard side. He couldn't have been that worried about it. One blade failed causing the imbalance.

[Boney]

Thanks for the info. I guess he was thinking of the operational aspect and putting up with two hours of vibration, which could have unintended consequences later on, as opposed to going to the nearest suitable airport where maintenance would be challenging.