SINGAPORE_AIR From United Kingdom, joined Nov 2000, 13606 posts, RR: 25 Posted (1 year 9 months 3 weeks 6 days 3 hours ago) and read 13346 times:
General Electric probes power loss on 3 recent 777 flights
By Stephen Trimble
An unusual rash of engine shutdowns since early December has temporarily stranded three of the normally reliable General Electric-powered Boeing 777-300ERs.
Although each incident involved a shutdown of the GE90-115B, GE’s investigation so far indicates the causes of each power loss appears to come from three different sources, says a company spokeswoman.
Among them:
1) 25 January / AF diverted to MXP: The engine’s transfer gearbox broke out of its housing, causing the power loss.
Keesje From Netherlands, joined Apr 2001, 9877 posts, RR: 51 Reply 1, posted (1 year 9 months 3 weeks 6 days 2 hours ago) and read 13256 times:
Quoting SINGAPORE_AIR (Thread starter): Although each incident involved a shutdown of the GE90-115B, GE’s investigation so far indicates the causes of each power loss appears to come from three different sources, says a company spokeswoman.
1. AF : excessive wear on a stage six low pressure turbine blade that “reduced contact pressure between blades on that disk
2. AF : the engine’s transfer gearbox broke out of its housing, causing the power loss.
3. SQ : undisclosed problem with the engine’s accessories gearbox
Recently we have seen shutdowns with -200ER's with BA, UA, JAL, ANA, CO, AF. I'm not suggesting they are not reliable or dangerous, but the "safer the quads" ads running here on a.net should watched with care.
Not so long ago twins had won over quads and ETOPS operation over 213 minues were just a question of time. Seems reality is a bit tougher. The FAA / EASA run on statistics & procedures, not opinions.
Birdbrainz From United States, joined May 2005, 401 posts, RR: 0 Reply 2, posted (1 year 9 months 3 weeks 5 days 21 hours ago) and read 12799 times:
It's interesting that it's the gearbox, not the turbine itself. My dad flew for UA and said that it's almost always the accessories that go, and the IFSD (in-flight shut down) is frequently done so that the engine isn't damaged. If power was really needed in an emergency, it would usually be there. Another cause of IFSD's are things like low oil level.
Not to take IFSDs lightly, but just because it's shut down doesn't mean that it couldn't be used in an emergency.
Given all the gearbox trouble, one has to wonder what the PW GTF (geared turbofan) reliability will be like.
A good landing is one you can walk away from. A great landing is if the aircraft can be flown again.
Ikramerica From United States, joined May 2005, 18437 posts, RR: 60 Reply 3, posted (1 year 9 months 3 weeks 5 days 20 hours ago) and read 12560 times:
Quoting Keesje (Reply 1): I'm not suggesting they are not reliable or dangerous
You absolutely are. Otherwise you wouldn't try to isolate the 777 issues from the general issues in the industry with all types having engine shutdowns.
My guess, and it's just a guess, is the you are seeing a lot of weird things because we are having an unusually cold winter aloft. But it's just a guess...
Of all the things to worry about... the Wookie has no pants.
Tdscanuck From Canada, joined Jan 2006, 5674 posts, RR: 56 Reply 4, posted (1 year 9 months 3 weeks 5 days 19 hours ago) and read 12397 times:
Quoting Birdbrainz (Reply 3):
Given all the gearbox trouble, one has to wonder what the PW GTF (geared turbofan) reliability will be like.
The gearbox is certainly the critical engineering component of the GTF, but PW knows that and I have to assume they're working appropriately. The accessory gearbox on a conventional engine isn't a particularly difficult thing to engineer, so the focus is always on making it as light as possible. Inevitably, somewhere something overshoots a little and you get reliability problems. The gearbox in a GTF is the heart of the engine, akin to the fan and HPT, and should get that level of engineering scrutiny.
Quoting Ikramerica (Reply 4):
My guess, and it's just a guess, is the you are seeing a lot of weird things because we are having an unusually cold winter aloft. But it's just a guess...
I'm not sure how much the engine would care...under-cowl temperatures can be pretty warm (200-400 degF). Colder outside would translate to colder inside, but not cold in any absolute sense.
Keesje From Netherlands, joined Apr 2001, 9877 posts, RR: 51 Reply 5, posted (1 year 9 months 3 weeks 5 days 19 hours ago) and read 12241 times:
Quoting Ikramerica (Reply 4): Quoting Keesje (Reply 1):
I'm not suggesting they are not reliable or dangerous
You absolutely are. Otherwise you wouldn't try to isolate the 777 issues from the general issues in the industry with all types having engine shutdowns.
Excuse me, I thought this Topic was on 777 / GE90-115. It seems GE is isolating 777 issues from the general issues.
PW100 From Netherlands, joined Jan 2002, 1594 posts, RR: 11 Reply 6, posted (1 year 9 months 3 weeks 5 days 19 hours ago) and read 12189 times:
Quoting Birdbrainz (Reply 3): Given all the gearbox trouble, one has to wonder what the PW GTF (geared turbofan) reliability will be like.
I wouldn't worry about safety, more about MTBR [Mean Time Between Removal]. Big gearboxes are required for the heavy power output, which means you have big gears and big bearings, running relatively slowly. Nice thing about that is that they start generating metal long before they actually fail. Meaning that usually there is plenty of warning time.
The engine type in my name has a Reduction GearBox capable of handling upto 2700 shp [small compared to the GTF], input rpm of around 20000 [GTF will be much lower] and output rpm of 1200. Once a bearing or gear starts to wear, it will lose metal particles [chips]. The PW100 RGB will run for another 50 - 200 hrs before catastrophic failure. I would expect any GTF gearbox being designed is such a way that it will not be a cause of IFSD. That is not to say that there will not be any maintenance headaches and unplanned removals.
The problem with AGB's [Accessory GearBox] is that they are usually much smaller as the power throughput is pretty small. A small gearbox uses small parts, usually running at higher rpm. When they start failing it is a matter of minutes to catastrophic failure. Most of the time that will cause an un-commanded shut down, as the accessories driving the engine [Fuel Pump, Fuel Control etc] stop running. The warning time is less that a single flight duration.
Regards,
PW100
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
The article also mentions "Both components have been installed on older-model aircraft equipped with GE90-94B engines, achieving an 11-year in-service record with no prior incidents before 25 January."
Not sure how accurate that is, I know of 3 GE90 failures with BA, maybe they were lower thrust rated engines.
Cathay Pacific wins Airline of the Year 2009 Award. Great service. Great people. Great fares.
M27 From United States, joined Oct 2004, 314 posts, RR: 0 Reply 9, posted (1 year 9 months 3 weeks 5 days 18 hours ago) and read 11972 times:
Quoting Zeke (Reply 10): The article also mentions "Both components have been installed on older-model aircraft equipped with GE90-94B engines, achieving an 11-year in-service record with no prior incidents before 25 January."
I read the article. No incidents! Its either about the GE-90-11x or its not. The question was asked why are you trying to isolate 777 issues from the general industry, to which the reply was as I have presented above. I would like to know how many GE90's UA has?
AirNZ From United Kingdom (Northern Ireland), joined Feb 2005, 3073 posts, RR: 12 Reply 11, posted (1 year 9 months 3 weeks 5 days 17 hours ago) and read 11787 times:
For goodness sake....can some of you not grow up, read the actual topic headline, discuss it sensibly and stop picking holes just to forward your own narrow-minded agenda's at every conceivable opportunity!!!!
WestWing From United States, joined Feb 2005, 1560 posts, RR: 5 Reply 12, posted (1 year 9 months 3 weeks 5 days 17 hours ago) and read 11732 times:
What I have been able to collate from FlySSC's and Iceman2's inputs in previous threads and from what has been reported publicly, there appear to have been a total of eight IFSD incidents on the GE90-115B. Please feel free correct this and/or add missing information - especially for incident (c) reported by Iceman2.
(a) 2007 Jun 26 Opr: AF Regn: F-GSQS Sch: PTP-ORY Diverted to: PTP
(b) 2007 Aug ?? Opr: NH Regn: JA7xxA Sch: NRT-??? Diverted to: NRT
(c) 2007 Sep ?? Opr: ?? Regn: ?????? Sch: ???-??? Diverted to: ???
(d) 2007 Oct ?? Opr: EK Regn: A6-xxx Sch: BKK-DXB Diverted to: BKK
(e) 2007 Nov 25 Opr: AF Regn: F-GSQE Sch: PEK-CDG Diverted to: LED
(f) 2007 Dec 12 Opr: AF Regn: F-GSQP Sch: ORY-RUN Diverted to: FCO
(g) 2008 Jan 28 Opr: AF Regn: F-GSQO Sch: ORY-RUN Diverted to: MXP
(h) 2008 Feb 01 Opr: SQ Regn: 9V-SWA Sch: SIN-CDG Diverted to: FRA
The best time to plant a tree is 40 years ago. The second best time is today.
RJ111 From United Kingdom, joined Sep 2004, 3068 posts, RR: 9 Reply 13, posted (1 year 9 months 3 weeks 5 days 17 hours ago) and read 11683 times:
Quoting M27 (Reply 12):
Quoting Keesje (Reply 1):
maybe they were lower thrust rated engines.
Maybe????? How many 200LR's and 300ER's does BA have in service?
They don't have any actually. Nor do they have any GE90-94s in their fleet. You guessed it, they have lower thrust rated engines, GE90-85s to be precise. Or Trent 895s for the non GEs.
M27 From United States, joined Oct 2004, 314 posts, RR: 0 Reply 14, posted (1 year 9 months 3 weeks 5 days 17 hours ago) and read 11610 times:
Quoting AirNZ (Reply 13): For goodness sake....can some of you not grow up, read the actual topic headline, discuss it sensibly and stop picking holes just to forward your own narrow-minded agenda's at every conceivable opportunity!!!!
You know what I find strange is that Zeke knows about these GE 90 failures of BA, and doesn't even know what kind of aircraft they fly!!! Makes me wonder if they really happened! Of course if he wants to provide a source, that would be great, otherwise, I might just believe they were RR.
Thanks for your wonderful advice AirNZ. I did read the topic headline, and I believe it mentioned 77W, so I'm going to assume you were talking to Keesje and Zeke and not me, because I do see a narrow-minded agenda there.
M27 From United States, joined Oct 2004, 314 posts, RR: 0 Reply 16, posted (1 year 9 months 3 weeks 5 days 17 hours ago) and read 11128 times:
I will say that if you want to go back to 1994 or 95, I'm sure you can probably find 3 GE90 problems, because I do understand they did have some introduction problems there. Maybe more than three.
Glideslope From United States, joined May 2004, 1319 posts, RR: 0 Reply 17, posted (1 year 9 months 3 weeks 5 days 16 hours ago) and read 10923 times:
Quoting PW100 (Reply 6): wouldn't worry about safety, more about MTBR [Mean Time Between Removal]. Big gearboxes are required for the heavy power output, which means you have big gears and big bearings, running relatively slowly. Nice thing about that is that they start generating metal long before they actually fail. Meaning that usually there is plenty of warning time.
Excellent point. Tight margins, tight competition, sagging economies = MTBR at the edge. Perhaps in some cases over the edge? Perhaps not?
No question the 773 these days with ( for Keesje, the GE-115 ) is not on the ground. I'll be interested to see what GE finds in MX logs.
"He wins his battles by making no mistakes." Sun Tzu
Birdbrainz From United States, joined May 2005, 401 posts, RR: 0 Reply 18, posted (1 year 9 months 3 weeks 5 days 16 hours ago) and read 10876 times:
Quoting PW100 (Reply 6): I wouldn't worry about safety, more about MTBR [Mean Time Between Removal]. Big gearboxes are required for the heavy power output, which means you have big gears and big bearings, running relatively slowly. Nice thing about that is that they start generating metal long before they actually fail. Meaning that usually there is plenty of warning time.
Sorry about that. I didn't mean that it wouldn't be reliable, just that it might be more maintenance intensive. I'm sure they'll do their homework.
About this thread, we seem to have a couple of things happening: There have been a higher than usual number of IFSDs of GE90s (of various types) that may or may not be related. From this, some have decided that this calls into the question the alleged safety of big twins versus quads. Fair enough, but I can't help but think some of that is because someone's beloved A340 has gotten beaten up too many times on here.
One thing to remember about IFSDs on quads: IFSDs don't make as much news, so you might not even hear about them. On the other hand, because it's not as big of a deal as with a twin, a crew of a quad is likely more willing to shut one down to avoid potential engine damage. Maybe these two offset each other, but it's really hard to compare IFSD numbers for each type of plane without a lot of knowledge of the circumstances for each IFSD.
A good landing is one you can walk away from. A great landing is if the aircraft can be flown again.
Fyano773 From Mexico, joined Mar 2004, 422 posts, RR: 1 Reply 19, posted (1 year 9 months 3 weeks 5 days 15 hours ago) and read 9947 times:
Quoting Keesje (Reply 1): Recently we have seen shutdowns with -200ER's with BA, UA, JAL, ANA, CO, AF.
Besides, AM 772 in the MEX-GRU run, suffered a stall in the GE90-94B last November. The plane was flown to ORD from GRU to have the engine fixed (replaced).
Stitch From United States, joined Jul 2005, 15987 posts, RR: 64 Reply 20, posted (1 year 9 months 3 weeks 5 days 15 hours ago) and read 9892 times:
Quoting Glideslope (Reply 17): Excellent point. Tight margins, tight competition, sagging economies = MTBR at the edge. Perhaps in some cases over the edge? Perhaps not?
With the sheer number of hours and units in operation compared to the number of incidents, it certainly does sound more like a case of the MX departments falling a bit short more then the engine design itself doing so.
Iwok From Sweden, joined Jan 2005, 1098 posts, RR: 1 Reply 21, posted (1 year 9 months 3 weeks 5 days 15 hours ago) and read 9531 times:
Quoting Keesje (Reply 1): 1. AF : excessive wear on a stage six low pressure turbine blade that “reduced contact pressure between blades on that disk
2. AF : the engine’s transfer gearbox broke out of its housing, causing the power loss.
3. SQ : undisclosed problem with the engine’s accessories gearbox
Quoting Birdbrainz (Reply 2): Given all the gearbox trouble, one has to wonder what the PW GTF (geared turbofan) reliability will be like.
Dude, you beat me to the punch. It will be very interesting to see how the reliability of the GTF pans out. If they can get it working, the secret sauce to the gear manufacturing process will be as big a trade secret as the formula for Coke.
TF39 From United States, joined Jul 2006, 98 posts, RR: 0 Reply 22, posted (1 year 9 months 3 weeks 5 days 15 hours ago) and read 9323 times:
Can incidents like these result in decertification (revoking) of ETOPS or lowering the time requirement (to land at a suitable airport) for the particular aircraft/engine combination?
Stitch From United States, joined Jul 2005, 15987 posts, RR: 64 Reply 23, posted (1 year 9 months 3 weeks 5 days 14 hours ago) and read 8962 times:
Quoting TF39 (Reply 22): Can incidents like these result in decertification (revoking) of ETOPS or lowering the time requirement (to land at a suitable airport) for the particular aircraft/engine combination?
For an airline, yes. I believe AF has already had their ETOPS certificate amended to a lower time limit because of multiple issues.
However, the 777 itself would not have it's ETOPS certification revoked or amended because the problem is almost assuredly not with the engines themselves. And if somehow it is a problem with the GE90 family as a whole, airlines flying PW40xx or Trent 8xx would be unaffected.
Tdscanuck From Canada, joined Jan 2006, 5674 posts, RR: 56 Reply 24, posted (1 year 9 months 3 weeks 5 days 14 hours ago) and read 8887 times:
Quoting M27 (Reply 16): I will say that if you want to go back to 1994 or 95, I'm sure you can probably find 3 GE90 problems, because I do understand they did have some introduction problems there. Maybe more than three.
I'll put up any amount of money you care to wager that there has never been a year since the late 90's, when the GE90 had less than 3 in flight shut downs. That would be a *shockingly* low number for an established fleet. The only way to have been that low would be to have few airplanes flying (right after introduction).
Quoting Birdbrainz (Reply 18): There have been a higher than usual number of IFSDs of GE90s (of various types) that may or may not be related.
IFSD rates are an average. Since they don't occur at a regular interval, by definition, some periods must have more shutdowns than average. So far, I haven't seen anything to suggest we're not just in one of those periods.
Quoting Birdbrainz (Reply 18): One thing to remember about IFSDs on quads: IFSDs don't make as much news, so you might not even hear about them.
The vast majority of IFSD's on twins don't make the news either.
Quoting TF39 (Reply 22): Can incidents like these result in decertification (revoking) of ETOPS or lowering the time requirement (to land at a suitable airport) for the particular aircraft/engine combination?
Eventually, yes. There is a shutdown rate for each fleet that must be maintained or exceeded to support their ETOPS rating. The OEM's monitor the actual shutdown rate and start getting proactive long before they get close to the certified rate. In theory, if enough shutdowns happened in a small enough span of time they could drive the IFSD rate above the threshold.
Keesje From Netherlands, joined Apr 2001, 9877 posts, RR: 51 Reply 25, posted (1 year 9 months 3 weeks 5 days 14 hours ago) and read 8691 times:
Quoting TF39 (Reply 22): Can incidents like these result in decertification (revoking) of ETOPS or lowering the time requirement (to land at a suitable airport) for the particular aircraft/engine combination?
Surprised to see the GE90 pic on last page. I remember asking the photographer to take it & authorizing it for PR many years ago
26 M27: And without asking for IFSD rates, would you not agree the same is true for equiv Pratt and RR engines?
27 MarkC: Just some info on IFSD's Most of the time they do not make news. The people on the plane might not even know. They would just know that they had to la
28 Stitch: Didn't see anything in a Google search. I did discover that NH was given ETOPS 207 on their PW4090-powered 77Es in mid-2002 by the Japanese Civil Avi
29 AirNZ: I actually wasn't meaning anyone specific at all M27. It's just that, especially lately, threads are turning into nothing but slugfests just for the
30 M27: Excellant post! You are truly correct. Hope that will happen! Regards
31 Tdscanuck: Absolutely! My point wasn't to knock the GE90, at all. My point was that the IFSD rate is *far* higher than most people realize. Three per year would
32 Mandrake: SWMBO (She Who Must Be Obeyed) and I commute between families in Canada and Australia every couple of years. For her, each flight is a kind of nightma
33 Glideslope: Yes, that's the norm in threads like this. Most people don't realize.
34 Zeke: M27, I get the impression that you are not aware that BA operate both GE90 and RR Trent engines on their 777 fleet. From what I understand the G-VII?
35 SunriseValley: I wonder if the gearbox problems on the GE 90 series are similar to those on certain of the CF6 series. The Power Plant engineer of a Pacific rim carr
36 Dakota123: I'm wondering the same thing. I am waiting for delivery of LM6000s (industrial version of CF6 used in power generation, gas compression, ship propuls
37 M27: How did you get that impression? I got the impression that you didn't know BA did not operate GE 11x series, and since the original posted article st
38 Zeke: I got the impression you thought BA only had RR powered 777, and were asking for a source to indicate otherwise. No, especially if you are talking ab
39 M27: It doesn't leave a lower thrust rating???? Zeke, I was talking about IFSD on the GE-11x series from the begining. Actually I never brought any other
40 Zeke: No, it was the article linked by the thread starter "Both components have been installed on older-model aircraft equipped with GE90-94B engines, achi
41 Lufthansa: singapore air, why on earth did you of all people for to mention the SIA 773ER shutdown? Yes what you say is true re the two AF ones, but the SIA one
42 Trex8: shouldn't the IFSD rates for ALL engines be publicly available from eg the certifying authorities rather than manufacturer press releases etc. or is t
43 Tdscanuck: Failure is extremely rare and, even when a failure does occur, the chances of an ill effect on the passengers are even tinier. An IFSD is considered
44 Zeke: He said rates, not events. The IFSD rate would just be a non dimensional statistical number, it would have no correlation to the number of events unl
45 Tdscanuck: Same problem, I think, possibly even worse. Without a reference, you'd be comparing numbers between fleets and operators on magnitude alone. In many
46 Zeke: I would not support it being broken down by operator or aircraft type, the IFSD rate for the worldwide fleet of an engine type I think would be usefu
47 Douwd20: The way information like this would be presented by the media is to get ratings. It would not be presented in a scientific manner but rather a manner
48 WestWing: Perhaps because of the secrecy, I have not been able to find any confirmation of the incidents (b), (c), (d) from my post # 12 above. For incident (a)
49 Trex8: agree you can get driver fatality/injury claim rates for cars on the road, how many people actually get swayed in their car buying by them? a very ve
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