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-   -   Uncontained engine failure at YSSY (https://www.pprune.org/rumours-news/595753-uncontained-engine-failure-yssy.html)

parabellum 12th Jun 2017 01:55


Maybe it was harmonic resonance. http://cdn.pprune.org/images/smilies/wink2.gif
Had that happen to me in 1968 on an AB206A in Indonesia! Compressor looked like a well chewed sweet corn cob and the engine shut down very rapidly! No blades or stators left at all. From the pictures looks as though the cowl failed.

underfire 12th Jun 2017 03:22

From a different A330 Trent failure..

https://www.flickr.com/photos/98001721@N00/

A30_737_AEWC 12th Jun 2017 03:42

Ahh, it's a nacelle failure, NOT an engine failure :ugh:


Originally Posted by jaytee54 (Post 9799217)
That's ahead of the fan! Would blades come off and forward? In all that inward airflow?

Don't flatter yourself and your engineering knowledge.

Can't you see that a significant part of the first stage low pressure compressor fan appears intact along with the spinner?

If you remember anything about convergent flow in ducts, you will remember that the static pressure in an accelerating stream of fluid/air flow drops compared to that of the freestream (external/adjacent to the cowl opening). There is a net suction inside the lip of the nacelle/cowl opening.

It's highly likely that the material that separated from the forward cowl/shroud initially was sucked inward in relatively large pieces, making it less likely that pieces of any significant size were ingested into the engine core. Some smaller pieces of debris may in fact have passed through the bypass (cold air) section of the engine.


Originally Posted by Uplinker (Post 9799220)
Isn't there supposed to be a kevlar blanket around the circumference of the fan to contain loose blades ??

Ah, not where there are not turning/burning engine components. This is an area of cowl/shroud AHEAD of any spinning parts (low pressure compressor). And there's no evidence that any blades of any sort were liberated.


Originally Posted by PAXboy (Post 9799687)
As the failure is on the inboard side - what happened to the portside fuselage?

You are assuming that high speed rotating objects were liberated from the engine/cowl.

That may not be the case, especially if the relatively light structure which 'disappeared' was sucked in towards the centre of the cowl/shroud.


Originally Posted by jaytee54 (Post 9799217)
That's ahead of the fan! Would blades come off and forward? In all that inward airflow?

Do you even understand what you are looking at ? :ugh:


Originally Posted by underfire (Post 9799693)
well, they did get a video chat from the engine! What is wrong with the press?!?!? I listened and I heard visual check, not video chat.......

I bet that the inspection and repair requirements of the cowl on that engine has been moved up!

http://services.casa.gov.au/airworth...011-0173R1.pdf

From the EASA AD identified by the link above, it seems that modifications were required to be incorporated to a number of A330 aircraft. Later build aircraft appear to have been delivered with modified cowls. Seems to me like a design/analysis screw up. Possibly the need to beef up the acoustic treatment/damping of the inner surfaces was identified at some point without properly assessing whether additional beefups were required at panel perimeters where attached to more substantial structure.

This AD goes back to 2011 with a revision in 2014.

An Airbus SB afford inspection and subsequent modification action.

One wonders if the airline has evidence of compliance with the ADs/SBs?

A30_737_AEWC 12th Jun 2017 04:19

A piece from the Guardian on the matter:

https://www.theguardian.com/world/20...-engine-casing

Some better images here:

https://au.news.yahoo.com/nsw/a/3589...failure/#page1

msbbarratt 12th Jun 2017 06:02


Originally Posted by A30_737_AEWC (Post 9799750)
One wonders if the airline has evidence of compliance with the ADs/SBs?

I was wondering if they have RR's TotalCare package, and whether or not that covers things like the cowl. Anyone know?

Presumably if they did, and it did cover the cowl too then it'd be down to RR to demonstrate compliance. Yes, I know it's part of the airframe, not part of the engine itself, I just don't know how much of the airframe is covered by RR's package.

bekolblockage 12th Jun 2017 06:07

Is the hole near the wing root a normal air intake/landing light mounting position? Or has it been made by damage from the cowling disintegration? Hard to tell at the resolution in Post # 1.
I couldn't see it on a few other A330's parked here.

Disregard. Found another photo showing it being a normal opening.

underfire 12th Jun 2017 07:05


From a different A330 Trent failure..

Ahh, it's a nacelle failure, NOT an engine failure
I have been stating the acoustic cowling failure issue with Trents.

It appears that the EgytpAir failure is virtually the same failure...

failure is failure.

mommus 12th Jun 2017 08:27

Assuming this is a failure of the cowl, and not the fan, who's responsibility is it?

RR don't build the nacelle - or do they?

Landflap 12th Jun 2017 09:45

Train for this over and over again. Fellas did a well rehearsed and competent job.

Arkroyal 12th Jun 2017 10:08


Originally Posted by jaytee54 (Post 9799217)
That's ahead of the fan! Would blades come off and forward? In all that inward airflow?

Since it's the fan pulling the aircraft forward, of course the fan blades go forward and outwards if released.

TURIN 12th Jun 2017 10:13


Don't flatter yourself and your engineering knowledge.

Can't you see that a significant part of the first stage low pressure compressor fan appears intact along with the spinner?

If you remember anything about convergent flow in ducts, you will remember that the static pressure in an accelerating stream of fluid/air flow drops compared to that of the freestream (external/adjacent to the cowl opening). There is a net suction inside the lip of the nacelle/cowl opening.

It's highly likely that the material that separated from the forward cowl/shroud initially was sucked inward in relatively large pieces, making it less likely that pieces of any significant size were ingested into the engine core. Some smaller pieces of debris may in fact have passed through the bypass (cold air) section of the engine.
Back to school lad.

The intake is a divergent duct. Convert ram effect to higher pressure and slower airflow.

Basic engineering knowledge. But you knew that.

Overboard111 12th Jun 2017 10:19


Originally Posted by Arkroyal (Post 9799998)
Since it's the fan pulling the aircraft forward, of course the fan blades go forward and outwards if released.

You'd think that but I've seen the damage done to the front luggage compartment of a Beech King Air that had a prop let go on take off and the holes were almost exactly in line with the prop hub exhibiting almost no forward movement at all. I expect a fan would perform similarly.

.Scott 12th Jun 2017 11:36

In most photos you can see that at the top of the hole the remaining cowling is bent well outward - suggesting that most of the separated cowling passed over the top of the engine. Almost all of the other tearing seen also suggests this upward motion.

A look at the inside bottom of the hole also shows metal bent up - in that case, toward the engine. This is best seen 0:33 seconds into this video:

https://au.news.yahoo.com/nsw/a/3589...failure/#page1

This suggest that the bottom of the separated cowling passed directly over the intake. It's hard to imagine (but possible) that none of it was ingested.

barit1 12th Jun 2017 11:38


Originally Posted by TURIN (Post 9800003)
Back to school lad.

The intake is a divergent duct. Convert ram effect to higher pressure and slower airflow.

Basic engineering knowledge. But you knew that.

Basic engineering knowledge. Without a LOT of airspeed, and certainly around Vr, there ain't much ram effect. We used to call it ram recovery speed; works well for you later in climb & cruise.

Caribbean Boy 12th Jun 2017 11:45


Originally Posted by mommus (Post 9799904)
Assuming this is a failure of the cowl, and not the fan, who's responsibility is it?

RR don't build the nacelle - or do they?

It doesn't matter who built any part of the engine, RR is the supplier and is responsible for any design or production defect.

Of course, the problem could have been caused by a maintenance error, so the Australian Transport Safety Bureau will be checking this out.

TURIN 12th Jun 2017 11:53


Originally Posted by barit1 (Post 9800079)
Basic engineering knowledge. Without a LOT of airspeed, and certainly around Vr, there ain't much ram effect. We used to call it ram recovery speed; works well for you later in climb & cruise.

Ram recovery typically will occur at about 160kts.

What's the take off speed of a typical A330?

lomapaseo 12th Jun 2017 16:11


Since it's the fan pulling the aircraft forward, of course the fan blades go forward and outwards if released
Not so fast. Give a thought to the lift forces vs time on the airfoil. The amount they move forward is miniscule before the airfoil effect is lost.

Kind of like an airplane glider wing that breaks off a toy

The forces driving the blade forward are friction like a skier on snow and only act at the tip surface

Jonny Suave Trousers 12th Jun 2017 22:12

So what happened?
 
I think we can agree now no fan blades left the engine and it was a failure of the cowling. Was this perhaps a panel not properly tightened?

A 'big bang' was heard by multiple different people on the ground over a Sydney suburb. (It's widely reported on social media), so we can assume the cowling went into the engine causeing failure?

Me thinks this is a mantaince screw up. It would be interesting to see who last had hands on the cowling.

ITman 12th Jun 2017 22:54

A seemingly similiar incident also involving a Trent 772 engine happened about 4 weeks ago, see Incident: Egypt A332 at Cairo on May 15th 2017, rejected takeoff due to engine failure.

Possibly related there may be two Airworthiness Directives released by EASA, see 2011-0173R1 of Aug 21st 2014 and 2016-0086R1 of May 13th 2016.

AD 2011-0173R1 reasons: "Two operators of A330 aeroplanes fitted with Rolls-Royce Trent 700 engines reported finding extensive damage to engine air intake cowls as a result of acoustic panel collapse, most probably caused by panel disbonding. This condition, if not detected and corrected, could lead to the detachment of the engine air intake cowl from the engine, possibly resulting in ingestion of parts by, and consequence damage to, the engine, or injury to persons on the ground."

AD 2016-0086R1 reasons: "During shop visit, cracks were found in several primary structural parts of Rolls Royce (RR) Trent 700 engine air intake cowls, specifically in the forward bulkhead web, web stiffeners and outer boundary angles (OBA). In addition, several attachment links were found severely worn, and some became detached. In two cases, the thermal anti- ice (TAI) piccolo tube was found fractured. Investigation results show that the cracks are most likely due to acoustic excitation and vibration. A broken piccolo tube, if not detected and corrected, in conjunction with forward air intake cowl bulkhead damage, could lead to in-flight detachment of the outer barrel, possibly resulting in damage to the engine or reduced control of the aeroplane."

TURIN 13th Jun 2017 00:27


Me thinks this is a mantaince screw up. It would be interesting to see who last had hands on the cowling.
As there are no removable panels on the intake, I doubt it.

Some have suggested the cowl anti-ice PRV failed. I'm not so sure. :ok:


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