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Japan's ANA cancels Dreamliner flights over engine trouble
25 Aug 2016 at 18:45 2,011 viewed0 comments WRITER: AFP TOKYO - Japan's All Nippon Airways said Thursday it is cancelling some Boeing Dreamliner flights owing to a problem with the plane's engine, and warned of more groundings. ANA has grounded a Boeing Dreamliner flight and is cancelling some others, citing engine problems. The carrier, the biggest worldwide Dreamliner operator with a fleet of 50 jets, said nine domestic flights scheduled for Friday would be halted so it could fix a problem with a Rolls Royce-produced engine. The move came after ANA grounded a domestic Dreamliner flight earlier Thursday, also citing an unspecified engine problems. "We will definitely cancel nine flights tomorrow and more afterward but we don't know the specifics yet," an ANA spokeswoman said. Japan's ANA cancels Dreamliner flights over engine trouble | Bangkok Post: business |
RR must be really busy sending legal teams, NDA reminders and C&Ds.
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Boeing 787 engine trouble prompts ANA to cancel some flights
Originally published August 25, 2016 at 10:39 am Updated August 25, 2016 at 2:31 pm Boeing 787 engine trouble prompts ANA to cancel some flights | The Seattle Times All Nippon Airways (ANA), the world’s biggest operator of Boeing 787 Dreamliner jets, announced Thursday in Tokyo it is canceling nine domestic flights on Friday because of a corrosion problem with the plane’s engines. Takeo Kikuchi, a deputy senior vice president of engineering and maintenance at ANA, told reporters Thursday in Tokyo the airline may have to scrap more than 300 Dreamliner flights through the end of September as it moves to replace parts inside the engines on a portion of its 787 fleet. The airline’s fleet of 50 787s are all powered by Rolls-Royce engines. About 38 percent of all the 787s in service are powered by those engines, while the rest are outfitted with General Electric engines. . . . GOES ON |
The apparent problem is hot corrosion caused by sulfur.
Sulfur in the fuel and airborne salts like sodium and chlorine reacts with the oxide layer on the blades in the high temperature environment of the turbine to attack the base metal of the blades. As a normal by-product of combustion, sulfur oxides are formed that combine with the salts and other elements ingested into the engine. This reaction forms sodium sulfates that expose the blade's protective oxide layer to decay. Water is also produced as a by-product of hydrocarbon fuel combustion, and this water can combine with the sodium sulfur compounds to produce sulfuric acid. Usually, the attack is worse in the blade shank or tip shroud areas and the actual gas path airfoil area looks pretty good. Because of this, blades have to be removed from the rotor disk to determine if cracks are present. And that is what ANA will do on all their RR engines. There are coatings that can be applied to mitigate hot corrosion. All jet engines including turboprop engines can have this problem to a degree. |
Turb D, would the corrosion depend on the properties of the fuel? E.g. Anti fungal, anti ice additives.
Are these occurrences focused on certain operators or world regions? E.g. Relatively high atmospheric sulphur content in volcanic areas. |
Safetypee
Short answer is all of the above - sulfur in the fuel, sulfur in the air, air pollution can all contribute. Plus, ANA was the first operator for the 787 and has the largest fleet to date (50 aircraft). So they tend to be the first to see longer term problems. |
Is this issue unique to Trent 1000 or other RR engines have similar issues?
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I don't have any specific knowledge about the ANA issue (I don't work Trent and I don't work 787). But as Turbine D noted, all gas turbine issues are susceptible to hot section corrosion due to sulfur and other contaminants in the fuel and air - it's just a matter of degree. There are coatings that are used on the turbine blades to prevent corrosion - some work better than others.
Educated guess here, but I suspect ANA had a turbine blade failure or a borescope finding. When the looked into it they discovered a widespread problem had developed and they needed to take prompt corrective action. |
safetypee,
There are two types of jet fuel used, Jet A and Jet A-1 in the Western world. Jet A-1 is used in Japan primarily because of its lowered freezing point compared to Jet A and the fact of many long distance routes flown including polar routes. The US uses primarily Jet A because more fuel is produce using the same amount of petroleum as a starting point, and therefore it is less expensive. Jet A-1 mandates an antioxidant be used and a static dissipator additive for safety reasons. Jet A requires no additives, but both jet fuels can have additional additives by agreement and approvals of authorities and engine manufacturers. Biocides and icing inhibitors are commonly added to both jet fuels. As I recall, additives are extensively tested at 4 times the maximum amount to assure no damage to engine components occurs. In fact biocides are beneficial in that they breakdown fungus and other microorganisms that produce acids when burned at high temperatures. So I think additives are pretty safe. notapilot, I would agree with tdracer's explanation. |
Historical note on 787 Engines
Very early in the 7x7 ( later to be 787 ) program- somerelatively young and MDC management was pushing for a single engine manufacturer- to save costs, etc. Several old timers pushed back and eventually won the day by insisting that more than one be selected from the 3 majors, AND that a standard ' pylon' and attachment scheme be imposed- sort of a ' plug and play ' concept.
The otheer ' selling ' point for more than one was the reduction of risk and less chance of a delay due to engines. Of course as it turned out- the engine risk was not the issue resulting in many many months delay. :8 |
I see ANA had another Trent 1000 fail yesterday. Must be a fun situation for the crews...
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Originally Posted by Una Due Tfc
(Post 9487115)
I see ANA had another Trent 1000 fail yesterday. Must be a fun situation for the crews...
NH609 August 20, 2016 NH959 August 14, 2016 This doesnt look good, seems ANA are taking no chances after the spate of their B787 engine failures... https://www.ana.co.jp/apps/info/info...6145351633.pdf Apology Domestic flights cancellation and delay due to Boeing 787 maintenance This information is valid as of 3.00 pm August 26, 2016 The safety of our passengers is our highest priority. ANA has decided to conduct inspection and maintenance work on the engines of a limited number of Boeing 787 aircraft. Due to this maintenance work, some flights on ANAs domestic routes will be cancelled or delayed on and after Friday, August 26. Details of the cancelled flights, delayed flights and information for passengers with reservations on these flights are as follows. Flights on the international routes will not be affected. We offer our deepest apologies for the concern and inconvenience caused to the passengers with reservations on these flights, and everyone who may be affected. 1. Cancelled and Delayed Flights Friday, August 26 (1) Cancelled Flights Tokyo (Haneda) Osaka (Itami) ANA15 08:00 09:10 ANA39 19:00 20:15 Osaka (Itami) Tokyo (Haneda) ANA20 10:00 11:15 Tokyo (Haneda) Fukuoka ANA255 13:25 15:15 ANA265 17:00 18:50 Fukuoka Tokyo (Haneda) ANA260 16:10 17:55 ANA270 19:40 21:25 Tokyo (Haneda) Hiroshima ANA683 16:55 18:15 Hiroshima Tokyo (Haneda) ANA686 19:00 20:25 (2) Delayed Flights (Over 20 minutes) No delayed Flights Saturday, August 27 (1) Cancelled Flights Tokyo (Haneda) Osaka (Itami) ANA25 13:00 14:05 Osaka (Itami) Tokyo (Haneda) ANA16 08:00 09:15 ANA30 15:00 16:15 (2) Delayed Flights (Over 20 minutes) Tokyo (Haneda) Yamaguchi ANA693 10:20 11:55 11:30 13:05 Yamaguchi Ube Tokyo (Haneda) ANA696 12:40 14:20 13:45 15:25 Sunday, August 28 (1) Cancelled Flights Tokyo (Haneda) Osaka (Itami) ANA25 13:00 14:05 Osaka (Itami) Tokyo (Haneda) ANA30 15:00 16:15 Tokyo (Haneda) Hiroshima Fight No. Dep. Tokyo Arr. Hiroshima ANA683 16:55 18:15 Hiroshima Tokyo (Haneda) ANA686 19:00 20:25 (2) Delayed Flights (Over 20 minutes) No delayed Flights Monday, August 29 There will be no flight cancellation or delays. Tuesday, August 30 There will be no flight cancellation or delays. Wednesday, August 31 (1) Cancelled Flights Tokyo (Haneda) Fukuoka ANA261 15:45 17:35 Fukuoka Tokyo (Haneda) ANA260 18:35 20:20 2) Delayed Flights (Over 20 minutes) Tokyo (Haneda) Kumamoto ANA645 14:50 16:30 15:10 16:50 Kumamoto Tokyo (Haneda) ANA648 17:15 19:00 19:20 17:35 Details of the affected flights in September will be posted on this website on or after Monday, August 29 once finalized. 2. To passengers with reservation on the affected flights. Please see the details from the link below for to change flights or refund if your reserved flight has been cancelled. Involuntary Changes due to ANA's responsibilities such as aircraft maintenance (Transfers to a Flight Operated by Another Airline)?Book Flights/Plan Travel [Domestic]?Flight Reservations?ANA August 26, 2016 All Nippon Airways Co., Ltd. |
Amazing what heat, liquids and gases can do even to titanium.
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notapilot,
The turbine blades would not be made of titanium, they would be a nickel-base superalloy. |
Hello D,
sounds a bit like "intergranular corrosion" ? doesn´t it ?? |
tracer, Turbine D, thanks for those points; one more question.
Is it likely that engine variants or build standards will have different blade coatings? Comment: ... additives extensively tested ... additives are pretty safe ... The sceptic in me recalls something similar being said about Type 4 de-icing fluids!!!! Wild thought: Was ANA one of those operators who were affected by ice crystal problems (GE engines though??). Would an operator be inclined to emphasise icing additives (by adding more), even though unrelated and unnecessary? |
Annex,
In a way, intergranular corrosion is a good description, but the mechanisms to reach that point can be different. One way is surface oxidation that develops cracks in the oxide layer that then spreads to the base alloy. The growth of grain boundary cracks in the base alloy is generally accelerated by composition changes. Another way is sulfidation (hot corrosion) of which there are two types depending on the temperature being experienced. Here the base alloy is attacked by the sulphur compounds which results in loss of alloy and pitting where the nickel in the alloy is consumed. The sulfur compounds continue down the grain boundaries where it depletes the chromium, leading to development of cracks. |
safetypee,
I don't think ANA has any of the GE engines designed for the 787s. Each engine manufacturer has proprietary in house turbine blade coatings and processes or may use patented coatings from a coating supplier that applies the coating. All I can say about the fuel additives is they are approved (or not) by multiple authorities worldwide besides the engine manufacturers. |
The coatings work when the process for applying them is followed to the spec.
If a batch traceable to a supplier and time period shows up in the failure/findings, go after the process and not the coating. |
Thanks Turbine D for the clarification, with all the publicity about titanium/CFRP fan blades, didn't know/assume that blades in most stages still have alloys. Is it a cost saving measure or steel alloys are better suited?
Do airlines boroscope engines as part of regular mx, if so how frequently. Also, is there any other Trent(not just 1000) operator with such short flight lengths, or ANA's situation is unique. |
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