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Emirates A330 Fan Blade - DXB 18 Oct

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Emirates A330 Fan Blade - DXB 18 Oct

Old 3rd Nov 2006, 09:20
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point taken
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Old 3rd Nov 2006, 09:33
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................Nacelle anti-ice on the Trent 700 is HP3, do I win a banana ? Customer bleeds are IP8 and HP6, ( another banana ? )
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Old 3rd Nov 2006, 09:59
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Just for us non-techy types that are following this thread with interest, can I just try to clarify how the nacelle anti-ice system works?

Is it that there is a pipe or pipes that bleed air from the third stage of the high pressure compressor in the Trent core and bring it forward to the annular leading edge of the nacelle? Here its inherent heat (due to it having being compressed) is used to ensure that ice does not form in the nacelle inlet.

Presumably the hypothesis therefore being raised is that at some point along that pipe(s), which presumably run between the nacelle liners and the cowling's external skin, an explosive failure occurred which had the effect of blowing out the nacelle/cowling material on either side.

If this is the case, then presumably the internal lining material was blown inwards and thus inevitably through the fan, although from the photographs this shows surprisingly little evidence of damage.
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Old 3rd Nov 2006, 11:47
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Cool

Of course you do Arnie Dan Otherdump.

Seloco, yes basically you're correct. There is a pressure regulating valve in there that should regulate the pressure to around 65psi I think.
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Old 3rd Nov 2006, 12:42
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Stuck on anti-ice will overtemp the cowl if left on for long times inight have even been stuck open since last turned on.

The inlet wall inner and outer walls are likely at lower pressures than the inside of the cowl and the only explosion would be the noise of it tearing away and going through the engine.
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Old 3rd Nov 2006, 16:26
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It's actually horrifying reading some of the nonsense that has been typed up on this thread!!!

First & foremost, it was definitely NOT a blade out, as anyone who has witnessed or inspected an engine which has thrown a blade; & I have only seen engines of much lower power capabilities which sustained this type of event; will show that the inlet & fan, plus casings, is totally catastrophic & beyond any repair, not to mention tail cones shearing off, gearboxes breaking their mounts etc etc, yet the engines still amazingly do generally contain all deadly potential missiles that result from this. They are manufactured & certified to do just this.
However in this case, the fan blades & rubstrip area appear in a beautiful condition totally void of any serious hardened metals or titanium fragments ingestion.
The blades apparently did have a few nicks & marks on some, naturally caused from the ingestion & chopping up of all the acoustic lining plus the outer carbon fibre material of the nosecowl, being sucked into the fan. At T.O. power settings they would have no choice but to go through the fan!
Also "apparently" this engine was only brought back to Idle power due the surge or parameter shifts, & remained at idle normally for the return & landing! If anyone can confirm this I would appreciate it.
My assumptions go along with Gaspath, I think, who said it most likely is a nose cowl inner barrel acoustic lining failure, for what reason no one is yet sure..... ingestion of FOD or material break-up?
I have my doubts about NAI as the supply duct enters the nose cowl at the 7 o clock position which is practically 180 degrees opposite to the panels that have been blown-out/sucked-in? those running around the right hand side of the cowl!.
Most definitely a nose cowl failure, whatever the cause.
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Old 3rd Nov 2006, 16:33
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Not sure exactly where the a/i valve is located in this nacelle. If the valve is well fwd, close to the inlet lip, it's possible the plumbing failure was on the upstream (supply) side of the valve, and the valve might have been closed the whole time.

But I'm not sure of the layout.
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Old 3rd Nov 2006, 16:55
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Anti - Ice valve is under the left fancase just above the starter.
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Old 3rd Nov 2006, 18:31
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Cool



Like here!

Last edited by spannersatcx; 3rd Nov 2006 at 18:43.
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Old 3rd Nov 2006, 19:32
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Another brilliant theory shot down...

Thanks, Jet II and spannersatcx.
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Old 3rd Nov 2006, 21:32
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Quick Q relating to the picture. Trent 700's: IGD's or VSCF Generators? Or dare i ask CSD? Ta.
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Old 4th Nov 2006, 13:24
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IDG's!
As one can clearly see by the photo so kindly posted by spannersatcx, the NAI valve sits aft of the fan rub-strip area, noted by the position of the kevlar wrapping(beige yellow material) around this fan frame which is the final containment medium of a fan blade loss & the deadly fragments of metal that result!
Hence, no rupture upstream of the valve possible, as this would be behind the fan & outside the strengthened fan case, & underneath the fan cowls, which were not harmed, nor I believe if the valve were open, there would or should be no pressure build up in the nose cowl as pressure relief panels would pop long before the cowl structure bursts!
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Old 4th Nov 2006, 14:32
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Originally Posted by spannersatcx



Like here!
G'day people. If you want the story that goes with this picture, check out, http://www.airliners.net/discussions...d.main/171748/
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Old 7th Nov 2006, 00:38
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Originally Posted by easyduzzit
My assumptions go along with Gaspath, I think, who said it most likely is a nose cowl inner barrel acoustic lining failure
Certainly possible, infront of the rubstrip there is a composite panel, which has been highlighted as missing and there IS an issue with these panels cracking around the rivet heads. I've been involved in 3 repairs of inlet cowlings due to this problem. No Mod Program has been announced as yet i dont think.

Originally Posted by howflytrg
Quick Q relating to the picture. Trent 700's: IGD's or VSCF Generators? Or dare i ask CSD? Ta.
Integrated Drive Generators on this engine.

The annulus fillers on the G2 weighed about 1 to 1.5 kg. I would guess that Trent 700 annulus fillers would have a mass nearer 2kg.
No where near that weight, they're lightweight made from composite. (Carbon Fibre i believe). With a small amount of aluminium to hold it in place between the blade. They weigh less than a kilo a piece. They'd just get sucked rearwards. no where near enough mass to escape the fan blades forwards.
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Old 7th Nov 2006, 08:06
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Hi there!

I don't know how to post pictures I'm afraid, but if you go to here (pdf):

http://www.aaib.gov.uk/cms_resources...201%2D4a%2Epdf

and look at the last picture, you'll see what a fan blade separation would look like afterwards. I think it's pretty clear that this wasn't a fan blade then.

The pdf is from the Kegworth crash investigation.

If anyone else can manage to post the picture it would be great!!!
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Old 7th Nov 2006, 08:42
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Hi there, slightly off-topic:
Would anyone care to explain in simple terms the difference between a Constant Speed Drive and an Integrated Drive Generator? Sorry, I'm not a techie.
Thanks
picu
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Old 7th Nov 2006, 08:59
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A Constant Speed Drive is just that. An input shaft varying with engine speed and an output shaft that is constant speed. The output shaft drives the generator. Usually filled with oil with a pump and a motor, but the BAC111 Spey engine had an CSDS which worked on air!
An Integrated Drive Generator combines a CSD and a generator in one package.
A VSCF is a variable speed generator. No CSD is involved. The frequency wild output is then converted to constant frequency in a box. On the B734 this box was bolted onto the generator, but on the B777 it is in the avionic bay.

Modern big jets all have IDG today. The B777 also has a Back up generator on each engine and a Convertor. Dont know about the A330.
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Old 7th Nov 2006, 11:21
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If memory serves me correctly, the nacelle anti-ice system is provided by a switchable anti-ice valve that allows warm bleed air into the cowl of the engine nacelle. The air is circulated around the cowl and escapes through the anti-ice pressure-regulating valve to atomsphere when it achieves a set pressure. The NAI anti-ice valves are controlled from the cockpit by pushbutton switches. When selected on, the switchlights illuminate blue when a set bleed air pressure is sensed in the cowl or illuminate amber to notify the pilot of abnormal operation.

If the anti-ice pressure-regulating valve malfunctions in the closed position, one would hope that some sort or overpressure regulating safety valve would release the bleed air from the cowl so that structural failure of the cowl would be prevented.

In the case presented in this thread, we are faced by a structural failure of the engine cowl immediately after the application of maximum thrust for the go-around. The engine does not appear to exhibit any evidence of blade or component shedding that might have precipated the failure of the cowl.

Where do we go from here?
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Old 7th Nov 2006, 12:53
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Offcial enquiry still ongoing!!!!

I haven't had time in my 30 mins allowed for lunch to read all the post's however!!!!

The story goes the cowl may have been bumped at BHX by unkown source, so there maybe a dispute to the second comment.

The aircraft had to do a last minute maneovre (Runway change) in which the aircraft became un-stable in its approach which resulted in a 107% overspeed of Eng 2 and Auto thrust was disengaged along with various fault messages appeared!

So later post's I saw reference Cowl damage induced by engine running at excessive speed may be true.

No blades were lost according to the report but lots of damage to the cowl and the N1 fan!!!!

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Old 7th Nov 2006, 13:07
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here's a postulation

If the anti-Ice was stuck on and operated in an warm ambient temp conditions (low altitudes) , the cowl would overheat weakening the composite walls. Then if the engine were increased to very high power while the aircraft was at low speed, with less ram air into the inlet, the sucking pressure drop across the inlet would act on inner panels and possibly delaminate them at their attachments. Since the inlet walls are made as panels, only the weakest one would fail.

This is only a postulation that might serve to provide some additional thoughts and checks to some confirmed reasoning.
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