Incident: Airbridge Cargo B748 near Hong Kong on Jul 31st 2013, both left hand engines surged at same time, one right hand engine damaged too

By Simon Hradecky, created Tuesday, Aug 6th 2013 17:24Z, last updated Wednesday, Nov 27th 2013 16:59Z

An Airbridge Cargo Boeing 747-800, registration VQ-BGZ performing freight flight RU-349 from Moscow Sheremetyevo (Russia) to Hong Kong (China), was enroute at FL410 about 80 minutes prior to estimated landing when both left hand engines (GEnx) surged simultaneously, engine #2 (inboard) temporarily shut down and auto-started again. The aircraft continued to Hong Kong for a safe landing on all 4 engines about 80 minutes later.

Rosaviatsia reported on Aug 6th 2013 that the aircraft entered a zone of dramatic temperature fluctuations, the temperature changing between -53 and -33 degrees C, when the engines surged, #2 spontaneously shut down and auto-started again without crew intervention. Both engines received damage to high pressure compressor blades.

In a safety message to operators released on Aug 20th 2013 Rosaviatsia rated the occurrence a "very serious incident" reporting that engines 1,2 and 4 were affected. Ice accumulated on unheated parts of the high pressure compressor in unpredictable and poorly understood meteorological conditions leading to the disruption of air flow inside the engine causing surges of the left hand engines. The flight was continued to destination, a post flight examination showed "unacceptable damage" to the high pressure compressor blades of engines 1,2 and 4 (both left and outboard right hand engine). Rosaviatsia is investigating the occurrence together with Boeing and General Electric, the FAA and EASA have been notified about this very serious incident.

On Nov 25th 2013 Boeing confirmed that a Multi-Operator-Message (MOM) has been sent to B747-8 and B787-800 customers, "who operate some GE-powered engines after instances of ice crystal icing that resulted in temporary diminished engine performance. To reduce chances of ice crystal conditions, Boeing also updated its Airplane Flight Manual (AFM) to prohibit flight within 50 nautical miles of large convective weather systems that may contain ice crystals. Boeing is working with its customers and GE to address the icing issue. Only a small number of GEnx engines have experienced the ice crystal icing issue in flight. GE will introduce the improvements necessary to return the engine to expected performance levels. Boeing is disappointed in any impact this situation may have on our customers, as is the GE team. We, like our customers, expect the delivered product to meet all expectations and will work closely with GE to address the subject condition. We regret the business disruption this will cause for our customer and remain ready to provide whatever assistance we can to Japan Airlines."

On Nov 27th 2013 the FAA released Airwirthiness Directive AD-2013-24-01 requiring operators of Boeing 747-8, Boeing 747-8F and Boeing 787-8 aircraft powered by GEnx engines to "revising the airplane flight manual to advise the flight crew of potential ice crystal icing (ICI) conditions at high altitudes, and to prohibit operation in moderate and severe ICI conditions. This AD also requires inspecting the engine after any ICI event is detected by the flight crew." The FAA argues that there had been reports of engine damage and loss of thrust in Ice Crystal Icing (ICI) conditions while flying at high altitudes. This type of icing does not appear on weather radar and thus often remains undetected by flight crew. Flying in these conditions leads to accumulation of ice crystals in the core gas flow of the engine. In events leading to prior airworthiness directives the ice had shed during throttle transients and in the descent phase of flight causing temporary loss of thrust, now newer events have occurred at cruise altitudes at or above FL330 while flying through a mesoscale convective system (continuous cloud larger than 100km/62 nm across). The AD reports that nine events have occurred leading to this AD, in two events two engines on Boeing 747-8 freighters experienced thrust losses, in one event both engines recovered, in the other event one engine remained at idle thrust for the remainder of the flight. In both events the two engines experienced thrust loss showed damage as well as a third engine that did not suffer a loss of thrust. On 4 events uncommanded engine decelerations occurred for about 20 seconds, in three other events on 787-8 aircraft at least one engine showed increased vibration levels until exiting the weather system.

Reader Comments: (the comments posted below do not reflect the view of The Aviation Herald but represent the view of the various posters)

@ Daneil ; apologies for typo
By Jock on Wednesday, Dec 4th 2013 00:33Z

Where I have written, in the last message, "Inverted comments", it should read, "inverted commas or quotation marks in comments".

My apologies.

@ Daneil
By Jock on Tuesday, Dec 3rd 2013 07:49Z

Look, Daneil, to keep this polite, I would evoke a pop- song,
"What's Love got to do with it?".

Quotation marks are for quotations. When I quote (i.e., when the expression is not mine in the context), I use quotation marks. That is their usual use.
One reason is that this helps to give the credit to the (identified or unidentified) author. That is a courtesy.

I may use inverted comments to "coin an ephemeral image". That is to help the reader.

Of what relevance is "love of God" in this aviation context.

I politely invite you to change your reading glasses, and to have a better day.

Correction of typo
By Jock on Sunday, Dec 1st 2013 18:55Z

Apologies !

I posted :"Decades ago, some GE & P&W engines were targets of one FAA Airworthiness Directive (AD) on ice issues. RR supportively, without finger-pointing, declared (i) this an industry issue, (ii) RR would watch progress on GE / P&W AD implementation & results (iii) pursue RR�s own efforts to ensure that all 3 engine-makers would be in the same, improved safety ban"

I should have posted : ".......(iii) pursue RR�s own efforts to ensure that all 3 engine-makers would be in the same, improved safety BAND".

Icing : an Industry Problem
By Jock on Sunday, Dec 1st 2013 17:57Z

Decades ago, some GE & P&W engines were targets of one FAA Airworthiness Directive (AD) on ice issues. RR supportively, without finger-pointing, declared (i) this an industry issue, (ii) RR would watch progress on GE / P&W AD implementation & results (iii) pursue RR�s own efforts to ensure that all 3 engine-makers would be in the same, improved safety ban
Initially, there was no such fair-play for RR Trent 800, after the B777-200ER crash-landing (hull write-off, but no fatalities) at LHR, of flight BA038.
In Official Enquiry reports, it was emphasized that there had been no engine or core icing on RR T800. Here, for GEnx-1B (bleedless) & -2B (bleed-air) engines, there has been ice-accretion.
At the time RR�s Sir John Rose�s statement, that RR T800�s were fully certified, & that this was an industry problem (as GE, Boeing & NASA now fully echo), was subjected to reported USA scepticism. Some loud finger-pointers in USA had even said the root-cause lay with RR. That is all over, now. That�s progress.

GE commit to implementing a fix
By Jock on Sunday, Dec 1st 2013 17:29Z

No criticism of GE or Boeing.
GE will overcome the problems.
They have committed to finding and implementing a "fix".

One hopes the fix will work. But it is regrettable to see recourse to fixes, on such a new engine-type, where the better option is to eliminate or neutralise root cause(s) by permanent solutions.

However, the fix proposed seems neat, and is the swifter, cheaper approach. And that opinion seems to be shared by rivals P&W & RR. Good news.

Root cause of incident
By Jock on Sunday, Dec 1st 2013 17:06Z

John, we all know that FOHE was in no way the root cause.
The nearest-to-root cause was fuel starvation of engines owing to build-up of ice-crystals in fuel-feed lines, between fuel-tank & engine, & causing clogging or choking in fuel�lines & filters. The root cause of the build-up of ice crystals & / or slurry in the fuel-feed lines between fuel-tank & engine is still being probed.

Under recommendations in AD & Final report, Air-framers, Engine-makers & Operators (notably Boeing, RR & BA in the LHR case)continue to collaborate constructively towards discovery of root cause.

The RR FOHE adjustment is not a permanent solution, but a fix, designed as an accompanying safety measure, which helped to disperse the clogging in the fuel-feed lines.

The root cause is still being sought.

@Jock
By Daneil on Wednesday, Nov 27th 2013 15:21Z

You're comments are interesting but, please, for the love of God, stop using so many quotation marks. You're using them so much it actually makes your posts hard to read. They're not necessary.

update markings
By tstueh on Tuesday, Nov 26th 2013 22:12Z

Hey Simon,

why did you stop marking your updated lines yellow as you used to do until the recent system crash? I - and I think others too - found it very useful!

Thanks for any reply in some way...

Engine Power Loss Due To Ice Crystals
By Graham on Tuesday, Nov 26th 2013 10:18Z

Boeing (and Airbus) and engine manufacturers have known about this phenomenon for quite a while because it has happened many times over the years on other engine types. It may be that the GEnx is more susceptible but time will tell.
For anyone who is interested Boeing had an article on this very problem in the 4th Quarter 2007 issue of Boeing Aero publication. It's at if you want to read it.

chill
By dirk on Tuesday, Nov 26th 2013 05:43Z

he guys, cool down...

Root Cause/Corrective Action
By John on Tuesday, Nov 26th 2013 03:00Z

Noted in part by Jock:- "In the case of BA it was fuel starvation of engines owing to build-up of ice-crystals in fuel-feed lines, between fuel-tank & engine, & causing clogging or choking in fuel�lines & filters".

Why have you failed to note the RR designed Fuel Oil Heat Exchangers (FOHE) as being the root cause of the problem ?

If this was the root cause of the BA777 accident at LHR; why did the corrective action not address the ice crystal formations in the fuel-feed lines?

The corrective action only addressed the ice clogging between the unheated protruded pipes above the inlet faces of the FOHEs by removing the protrusions which Boeing and RR determined to be the root cause of the engine roll-backs.

Boeing 777s powered by Pratt and GE engines experience icing in fuel feed lines from wings to engines but do not experience engine roll-backs.

Just passing on this feed-back
By Jock on Saturday, Aug 24th 2013 21:36Z

I pass on feed-back from a knowledgeable engineer with whom I correspond. He says : �Not a case identical to BA�s on flight BA038 though both had, in part, the same sort of result.

"This is a case of HPC compressor clogging with ice, resulting in Air starvation or choking of an engine. In the case of BA it was fuel starvation of engines owing to build-up of ice-crystals in fuel-feed lines, between fuel-tank & engine, & causing clogging or choking in fuel�lines & filters.
This is similar to another BA incident (B747) where 3 engines shut down, �just like that�, owing to �ingestion� of volcanic ash.

"What surprises me is that such a very serious incident is reported in media after a lapse of more than 3 weeks.
There is a no easy solution for preventing this kind of icing. All makes of engines are prone to such choking if flown through such severe weather conditions."

Without wishing to contradict Roly, this tends to reflect some of, e.g., Fanman�s & my own remarks.

@ David H.
By Jock on Saturday, Aug 24th 2013 20:56Z

Daniel H, never shoot from the hip.

The remarks I quoted are not ones made by Simon H. Reportedly "official", they are ones (Oral or written? Neither you nor I know!) that I picked up, or was fed, from other sources. The words / phrasing are as I found them. I was astounded. You did not even notice.

(i) I respect Simon H. & his site-rules. I sought to avoid pre-empting his "new news" from his continuing research. He has ways of validating the "authenticity". In this specific context I do not (& recognise it). Nor do you. E.g.: where did you ever read that an official, statement of the investigators was: "Currently, additional measures are being taken to change engine design & develop recommendations for the flight crews on actions in such conditions"?

(ii) Simon's polite, direct reply shows he understood my doubts & questions. He confirmed & cleared my doubts. The incident is serious. But that sort of statement is more than disturbing, at this stage of any investigation.

@ Simon H.
By Jock on Saturday, Aug 24th 2013 20:42Z

Thanks Simon H. for this reply. Excellent. Right to the point.
You understood my concerns straightaway.

You have confirmed and clarified my doubts over the "unlikely authenticity", as well as over the odd wording.

The issue is serious enough without one's having to "de-code" such peremptory & "invasive" remarks.

Obviously, I know that you can validate, and have validated, what you have "penned".

Thanks again.

@Jock
By Daniel H on Saturday, Aug 24th 2013 19:52Z

Some of these "comments" have made for very painful reading.

Imagine our non-native English speakers having to wade through such nonsense. Considering a substantial percentage of visitors to this site are not native-English speaking, some of these posts actually embarrass me.

Jock, do you talk the way you type? Just wondering.

Also, if you "should be grateful if Simon H could up-date us on the *authenticity of the alleged*[!!!!] official remarks of the Russian Authorities," then I don't think this is the place for you.

Because if it was, you would know FULL WELL that if Simon says that Rosaviatsia said what he said they said, then you can bet Rosaviatsia said it. Besides, how exactly do you expect to be "updated?" Have Simon ask Rosaviatsia to give you a call? Maybe get them to DHL you an "official copy" of their preliminary report, fully translated for your convenience?

Personally, if I were you, I would be "grateful" to be allowed to keep posting.

@ Jock Aug 24th 2013 09:40Z
By Simon Hradecky on Saturday, Aug 24th 2013 17:37Z

Neither of those remarks is authentic or coming close to what Rosaviatsia (Russia's Civil Aviation Authority) said.

However, I do confirm that what I wrote in my story is authentic and a very close representation of what they did say (it is not a translation however).

Do not underestimate the seriousness....
By Jock on Saturday, Aug 24th 2013 10:28Z

No underestimating the problem here, especially if the authenticity requested is confirmed
No attack on GE. This is about safety & airframe & engine reliability.
I refer to Fanman's blunt, factual, hard-hitting post:
-- �By Fanman on Wednesday, Aug 7th 2013 08:04Z
Booster icing is a problem for the GEnx-2B, so much so that they have had to heat the inlet stators. Couple that with a poor HP Compressor stall margin and the stated 20�C temp fluctuation, it's hardly surprising that the engines stalled.
The thermal shock alone would probably be enough to cause blade damage, never mind the possibility of slivers of ice going through the core. �
-------
There is no room for self-appointed cheerleaders� �huffing & puffing�, talking up GE.

The true GE professionals will be buckling down to the task, paying no heed to such trash.

GE know there are issues to be solved on GEnx (-1B & -2B). They will solve them. Work is required. Bad-mouthing RR is not even in the frame for GE, or Boeing.

Do not underestimate the seriousness....
By Jock on Saturday, Aug 24th 2013 09:40Z

I do not intend even to try to circumvent AVH site-rules & / or infringe copyrights.

But I should be grateful if Simon H could up-date us on the authenticity of the alleged official remarks of the Russian Authorities, of which, reportedly, these would be a sample:
--"unacceptable damage of high pressure compressor blades on engines 1, 2 and, apparently, 4..";
-- "(it is) mandatory to use all available design means capable to aid [in identifying] icing of airframe & engine elements at the earliest phases of its start-up ..";
-- ".. dangerous incident. Currently, additional measures are being taken to change engine design & develop recommendations for the flight crews on actions in such conditions."

If these remarks were confirmed as official, it would seem high time to stop intellectualising the problem, and to recognise the seriousness of this incident.

Fancy Engines
By Roly on Friday, Aug 23rd 2013 17:58Z

Of course in the days gone we had a flight engineer on the flight deck watching every variable and giving the mix the odd tweak on the throttle to keep the engines sweet. No Fadec is that clever.

@ Fanman ("Off Topic") & Iceman2
By Jock on Friday, Aug 23rd 2013 16:21Z

Fanman, you wrote:"How ....fuel contamination when the stated engine damage was to the HP compressor caused by disruption of the airflow (ice?)... no fuel in the compressor system. Yes, temporary fuel starvation by ice blockage in the fuel system may cause a surge upon resumption of fuel flow which may in turn damage the compressor stators and blades, but that is not what was stated to have caused the problem".
---------
I indicated my flippant reply. Without seeking argument with Roly & Co., my exchanges with my "RR-zone" sources reflect this. I did write : "Opinion is that it is NOT an issue of fuel ice / slurry through the fuel-feed system".
----------
It is clear that I have no issue with your post, or your remark : "Yes, temporary fuel starvation by ice blockage in the fuel system may cause a surge upon resumption of fuel flow which may in turn damage the compressor stators and blades, but that is not what was stated to have caused the problem".
----------
Iceman2, I see no drivel in that.

@ iceman2
By Jock on Friday, Aug 23rd 2013 16:02Z

Iceman2, do not accuse everyone of writing drivel on this subject. You & Fanman, though highly knowledgeable, are not the only ones who have studied long & hard this subject. We know that GE, P&W & RR have devoted energy, time & money to it.

On one point, which I take up here again, I have had it confirmed to me by persons of all three, that GE & P&W, like RR, had experienced the problem of fuel starvation of certain operators through ice-accretion in the "fuel-feed systems" & outside the engine.

RR's issue at LHR on flight BA 038 was dramatic, because the really "hard" point was at very low altitude. GE & P&W were frank enough to recognise that they had had the problem at high altitude (then dropped altitude, and used increased power at the opportune moment). They added that, back on the ground, attempts at analysis of the exact causes of the incidents, were frustrated totally owing to absence of physical traces enabling, e.g., "reconstitution for analysis".

Jacksie Syndrom
By Roly on Friday, Aug 23rd 2013 15:15Z

One of my Teckels..Wieners..Dachshunds is called Oetzi..the dumbest of my 5 strong pack. No personal reflection on you Iceman 2..

Me and three collegues spent 13 weeks on the RR Trent 972 and the stuff we dug up would scare any would be passenger away for life.

Now if you would all refocus your efforts over on the UPS Accident thread that would be good. But you gotta be able to add up and do some math.

You also have to have some character too.

By on Friday, Aug 23rd 2013 14:12Z

Thanks Roly ; the regrettable RR T 900 incident, on Qantas A380.
By Jock on Friday, Aug 23rd 2013 13:54Z

Roly, I am just an amateur in this context. But I aim to be thorough.

The regrettable RR T900 incident, Qantas A380, saw RR�s front-line-responsibility, rightly assumed by RR (no option).

There was no technology or fundamental design-flaw issue. And, despite all the points in the thorough final report, it was RR who had discovered the flaw (officially : manufacturing- process defect, in the �counter-boring� process, causing �thinning� of the oil stub-pipe wall, leading to oil seepage & an exceptionally but inevitably violent �oil-fire explosion�, with the well-known results, which could have been severely more far-reaching, close to major catastrophe).
AD issued was a �non-modification� AD, i.e. an �inspection AD�. That alone speaks volumes.
Some published documents (difficult to find now, owing to the sub-iudice nature, & confidential details of the �settlement�) tended to show what some construed as operator�s contributory negligence (non-application of mandatory SB�s).

Modern Turbofans
By Roly on Friday, Aug 23rd 2013 09:29Z

The principals of this engine have been around since the early 1900s and if you look up "Turbinia" this was the first application. Back then fluid dynamics was not an academic discipline. In a turbo fan application the air is in fact the "fluid" so all the eng students get well briefed in this discipline. The reason why we wanted to know the mechanism of how the blades were made to turn would tell us why they suffered damage. The were "shock loaded". The air acts like a fluid and causes tremendous loads..point loading down at nano molecular level on the leading edges and tips of the vanes. This rips molecular chunks out of the titanium alloy blades and cause tears and pits. The FADEC is a feed back loop that controls fuel delivery and is there to protect the engine from self harm. Whatever both GE and RR say we believe that the cause of this is fuel starvation due to "dirty" fuel.

@ Roly ; addendum ; sorry...
By Jock on Friday, Aug 23rd 2013 09:17Z

Sorry for the untoward break and the "uncontrolled posting" of the preceding post.

I simply wanted to say that I thought, from my own amateur understanding, that cavitation was a symptom showing up on a fuel-tank pump, suggesting non-functioning, or mal-functioning, notably if there had been lack of fuel-flow etc.

Given "my other experts'" feed-back & remarks, I am wondering if "cavitation" is relevant here.

"Amateur" No Jock!
By Roly on Friday, Aug 23rd 2013 07:25Z

Jock: Gifted people like Einstein, Tesla and Porsche were all "amateurs". Gifted people in business such as Richard Branson can be dyslexic...cannot write or add up correctly. Don't run yourself down. Time upon time it has been proven that persons who should know what they are about really are frauds. Often the motives they have not for the good of the people..only for their own selves.

@ Roly ; addendum
By Jock on Friday, Aug 23rd 2013 06:43Z

Roly,... no "polemics" ; just feed-back from an engineer working with RR at this time (NOT a salaried employee):

-- For obvious reasons, RR are following this story closely.
-- This engineer confirms that he & RR are adamant that this is NOT a problem of icing through slurry forming in the fuel- feed system, between exit point from fuel tank, and engine.

They say that my "content" is the sort of position they have adopted.

They added, in passing, that it is correct that there are variable-pitch vanes in the HPC zone, NONE on the booster.
-----

By the way, from my own very amateur understanding, I though that caviut

Turbofan Manufacturers
By Roly on Friday, Aug 23rd 2013 06:22Z

Thanks for that Jock. My mind is still tainted with that Trent 972 accident of the big Qantas A388 at Changi. The accident where that big rotor was thrown out of the engine. No...time to move on.

Big technology Jump on RR ?
By Jock on Friday, Aug 23rd 2013 05:50Z

Roly, just to get the meaning straight, it is RR who are well ahead of GE.

GE have a huge jump, ... to make to get back into the same technological frame as RR.

But these things do not remain static. And GE has the capability of throwing money at any issue to overcome it.

But that is not enough. One needs money, time, experience & "self belief" to master the subject, especially one such as thermal dynamics and airflow through the engine, where time & experience are so important.

When GE are having problems with an engine (as is visible -- & perhaps normal ; let's not criticise -- on GEnx-1B & -2B variants, respectively on B787 & B747-8), they try to deviate public focus thereon. They always direct attention to the "next engine", saying it is the "nec plus ultra", ... the "best thing since sliced bread" !

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