Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
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- Boeing CFO: we want to negotiate; taking steps to preserve cash September 13, 2024
- Bjorn’s Corner: New engine development. Part 23. New versus old, GTF versus V2500 September 13, 2024
- IAM files Unfair Labor Practice against Boeing in thumping rejection of contract September 13, 2024
Perspective on 787/GEnx engine event at Charleston
It wasn’t even 10:30 PDT and we had already received quite a few phone calls from media and Wall Street asking what we thought of the weekend engine event on an Air India Boeing 787 equipped with GEnx engines during a test at Boeing’s Charleston plant.
The airplane was on a runway when some parts shot out the tailpipe. The hot parts set grass along the runway on fire, closing the airport for an hour.
You can find a lot of stories on Google News but this one is typical–and, in our view, the headline is overly inflammatory.
We saw the early Tweets about the event and pretty much shrugged the event off. It was a test flight, it’s a new engine type, engine “events” happen more than the public or media realize, nobody was hurt, what’s the big deal?
So we’re surprised by how much interest this generated. True, it’s on the 787 and program difficulties mean that the paint could peel and it would become a headline.
Here’s what we’ve told those who called:
- We’re not concerned. Engines spewing parts is not unknown. It’s the nature of anything mechanical and with a new engine type, the prospect of glitches is elevated. It’s all a matter of context.
- There is no connection between this incident and the engine failure on the ANA 787. ANA’s airplanes are powered by Rolls-Royce engines; this incident was a GEnx engine.
- Any suggestion (and there were two) that this might have something to do with the presumption the airplane was made in Charleston is just silly. The engine was made in Ohio (or some other GE plant). Furthermore, there are three Air India airplanes in Charleston, two of which were flown there from Everett. We don’t know which airplane was involved.
- The authorities, GE and Boeing will consider as cause (in no particular order): FOD (foreign object damage–did the engine ingest something that caused the parts to separate and eject from the rear?; design flaw; defective part; and human error in assembly.
Based on what little is known right now, we don’t see any material impact, if any at all, to the 787 program.
Well that project dont need another unknown right now. How many times have the 787 been delayed now? Its fun to speculate, what if someone left a nut or a bolt in the engine?
‘Once is happenstance. Twice is coincidence. The third time it’s enemy action’.
We are still at happenstance, thus a non issue.
is out not also inflammatory to describe the ANA engine issue as an engine failure? no engine failure occurred, it was a precautionary replacement of a defective part.
For once, Uwe and I agree on something. This is a non-issue.
Quick question, has the GEnx-2B67, which powers the 747-8, reached a more advanced state of maturation than the 787’s GEnx-1B?
23 848-8* at end of june delivered. i.e. just short of 100 engines in revenue service.
except for sfc issues nothing in the press.
100 engines was the number the Boeing spokesperson seems to have referenced,
though I think the GENX -1 and -2 versions are different enough to question this “umbrella”
statement.
I see that investigations into an engine failure on a -2 in Shanghai have led to an “umbrella” state of assumptions on the GEnx family, loosely linking it to the -1 event in Charleston [assumption], which I’m guessing are probably manufacturing quality issues.
The lateness of this reply, together with ongoing investigations have allowed me space to rethink my original comment, which admittedly, was skirting umbrella closely, on the assumption of the use of some* common parts and manufacturing processes by the GEnx family manufacturer. While the various GEnx engines have significant differences in stages, fan diameter, rated thrust, and bleed air, etc., the same company builds them. My comment is still way too general, but I think it’s an interesting point. Apologies for bringing this out so late.
“While the various GEnx engines have significant differences in stages, fan diameter, rated thrust, and bleed air, etc., the same company builds them.”
What I’ve read is that in this case the same process change applied.
On the other hand the 748 failure is said to be “different” to the 788 fault.
I don’t think so. The GEnx-2B engine is the second version of the GEnx family. The 1B engine began testing back in 2006 and received its FAA certification in 2008. IIRC, the -2B engine was about two years behind its sister engine and received its FAA certification in 2010. Both the -1B and -2B engines share some design features of the GE-90-94B’s HPC. There are major differences between the two engines, too. The GEnx-1B engine has a 111″ fan section, a 4 section LPC, and no bleed air extraction. The GEnx-2B engine has a 105″ fan section, a 3 section LPC, and bleed air extraction.
Poor question on my part, my bad
Thing that caught my attention is the involvement of the NTSB. Very unusual for something this “minor”.
To me it sounds like it could have been a compressor stall. When this occurs there is often a big flame that comes out of the tail pipe. Maybe that is what set the grass on fire. On a really bad compressor stall you could also have parts that would come out of the engine; but they would come out the front due to the back pressure.
Whatever the cause might be, the media reaction is indicative that the 787 program is still under the microscope. 🙁
the media reaction is reminiscent of the a380 wing-ribs issue.
bad reporting as usual from the mayor news outlets. Thank heavens for the oasis that is Leeham news.
Seen on A.net !
http://www.charlestonbusiness.com/news/44668-ge-to-ship-damaged-787-engine-to-cincinnati-service-facility?rss=0
GE seems focusing on a LPT mishap, may be a blade out !
The engine is rushed to Cincinnati these days for investigation !
“We don’t know the cause,” Kennedy said. “But we’re focused very heavily on the low-pressure turbine.”
IIRC Volvo Aero and MTU is involved with the GEnx? Its not entirely 100% american. Will that complicate things if there is an issue to fix?
The LPT is made by Avio and IHI (50% each), one makes the stators and casing and one the blades + discs. Volvo Aero makes the TRF. Do not remember who makes the TCF, but the HPT is GE.
If it was a minor issue we would have known days ago.
I agree, keesje. But in the same light I don’t see this as a major issue, like the RR Trent-900 engine had. Right now I think it should be catgorized as ‘unusual’. It is not the first engine to throw parts out the tail pipe. It may end up being a ‘contained engine failure’, but we don’t know that yet. Did the crew keep the engine running after the event? Was it a compressor stall that started the sequence of events within the engine? We just don’t know anything right now. The engine is back in Ohio now and being torn-down. The GEnx series have logged about 125,000 flying hours now without an inflight event, even though most of the flying time is by the smaller and younger sister engine, the GEnx-2B-67 of the B-747. I do agree that is still a short time, the other engine offered on the B-787, the Trent-1000 has less than 30% of that time, but it does take time to build to maturity for both engines.
Last week NH discovered a quality control issue with corrosion of a gear in the gear box of some Trent-1000s, and the issue was immediately addressed by both Boeing and RR. I suspect GEnx event is also a quality control issue with this perticular engine, and it will be addressed by GE and Boeing when the cause has been determined.
I might add Boeing did not mention any damage to the airplane itself, just that one engine.
Did the parts come out of the tail pipe? Sometimes they come out sideways, e.g landing next to the runway.. we don’t know. It is to early to downplay this. If Boeing had any opportunity to difuse thix they would have IMO.
to distract the attention a little 😉 nothin is clear yet on the Hamilton Sundstrand gearbox of the ANA 787 yet too..
KC135TTopB
” For once, Uwe and I agree on something. This is a non-issue.”
Sorry guys, anytime a jet-engine spews flaming-hot metal-parts out of of
it’s tailpipe or it’s front, it is a very serious matter, until proven otherwise!
Good thing the a/p was NOT in the air and the pilots being un-aware,
until after it had become a very serious safety issue!
news from the NTSB:
http://www.heraldnet.com/article/20120808/BLOG01/120809792
http://www.ntsb.gov/news/2012/120808.html
fan shaft failure. ouch.
detailed pics, balanced article:
http://www.bangaloreaviation.com/2012/08/ntsb-traces-air-india-boeing-787-genx.html
It will be interesting to know what data was captured on the combined DFDR/DVDR (there is only a single black box now for the B-787, not two boxesas in prior airplanes, it may also be in use in the B-747-8). Also if the mid shaft passes the metal test, it could indicate an assembly error.
One would have to see the actual defective part.
Overrewing of the lpt only happens if the coupling is separated.
With only the nut/threaded head of the shaft separated The fan/booster
assembly would try to move forward while the rear moves backwards.
Assuming? that the trust bearing is in the front only the LPT can move backwards.
Destruction by collision of turbine blades against stator vanes.
some one mentioned FOD taken up from the runway but I don’t see
a path to achieve this fault with FOD?
Apropos:
my understanding is that the 787 has dual combined DFDR/DVDR i.e. two identical boxes that both carry records of all relevant data.
The dual combined DFDR/DVDR, is this specific to Boeing, or is it required by the new regulations? What about recent designs like the A350 and CSeries?
no idea. That was information picked up from one of the broken GENX articles.
But it is only logical. ( it is a combined box for commercial shipping. “VDR” installed two last year ;-.)
Anyway storage and data collection seem to be two different boxes these days.
There is a longish article in the FAST #48 pdf from Airbus.
It is my understanding this is the new black box designed to replace two boxes. The combined box weighes about 40% less then the two box combination. We know it is in the B-787 now, and I suspect it was designed into the new B-747-8. I suspect we will next see it in the A-350, A-320NEO, and B-737MAX airplanes.
Some details:
http://asasi.org/papers/2007/The_Evolution_of_Flight_Data_Analysis_Neil_Campbell.pdf
elsewhere: A380 is prepared for an Arinc 767 style FDR setup.
http://www.aviationtoday.com/av/commercial/Product-Focus-Flight-Data-Recorders_11670.html
This morning in the news here:
A380 RR engines have to get inspection after an event in july.
ref? : http://ad.easa.europa.eu/ad/2012-0145
Misery does not only like company.
Todays it mandates company.