Planespotters’ weekends turn traumatic as engine pieces fall from the sky in the Netherlands and the US In what can only be described as a bad day for Boeing, not one but two of its planes suffered engine fire and began shedding parts along their respective flight paths. Shortly after takeoff, a Boeing 747-400 cargo plane flying from Maastricht Aachen airport in the Netherlands to New York on Saturday afternoon suffered an …
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Early reports indicate internal metal failure of the hollow titanium fan blades, cracking without notice until the crack passes into the external skin surface causing blade separation.
As much as people would like to point fingers at Boeing nowadays :D this is completely not Boeing's fault.
The FAA's emergency inspection will call for additional internal blade inspections, using technologies such as ultrasound.
"light touch" regulation? you mean like the same "regulation" effect recently seen in Texas? the same (purposeful lack of) "regulation" seen over the last four years in the u.s.? the same lack of "self-governance" from certain groups in the u.s. as encouraged by those who for any amount of campaign contribution will champion "light-touch" laws? those?
the last four years in the u.s.?
You've had it for a lot longer than that. Hence, the "subprime" mortgage fiasco and Boeing's self-certification of the MAX and all the other wonders you get.
Though, to be fair, I wouldn't put the omnishambles in Texas in that particular bucket. Texas has deliberately opted to avoid the national grid, which is why, when the Texan generators of all sorts went down, it wasn't possible to pull in power from other states. No, I don't expect that to change anytime soon either.
This is mostly false: Texas has two low-capacity interconnects to the Eastern Interconnect (i.e. the grid for the eastern states of the US), and two low-capacity interconnects to Mexico.
Since someone will quibble about the words "low-capacity":
Texas power generation capacity: ~34,000MW
Texas North DC Tie (to Eastern Grid): ~220MW
Texas East DC Tie (to Eastern Grid): ~600MW
Texas Railroad DC Tie (to Mexico): ~300MW
Texas Laredo DC Tie (to Mexico): ~100MW.
Total tie capacity (either importing or exporting): 1,220MW aka 3.6% of the state's generating capacity.
30% of the capacity was offline because of the wrong type of snow...
Texas DOES connect to other states--usually it's to export (at lot) of power.
Most of what I've read says that the interconnects are tiny, relative to the total state grid. The total power that could come across those interconnects (they are AFAIK DC interconnects for power trades, they aren't a grid-level synchronized AC interconnect system) was irrelevant to the scale of the power loss in Texas, they could only provide a tiny percentage of the power deficit.
I can't find the specific news article I read that in (~10 minutes searching), the closest one I could find:
the state is intentionally isolated from the rest of the country, with the exception of very small ties that are used for limited power trades;
Here's one for you, written after the 2011 power failure (why yes, Texas has had state-wide failures before): "Why Does Texas Have Its Own Power Grid?"
Texas refused to join the US national grid to avoid Federal oversight among other reasons.
I suspect there may be changes in even local regulation coming soon, particularly after the Texan power companies trying to charge as much as $5K to householder for five days use of power during the freak winter they have just had. Apparently they use a pricing auction system based on the level of demand.
Nope. Look up the term "redlining". If it was real, then banks were staying out of entire zip codes because racism. If it were real, then opening up a bank & targeting loans to the affected areas would allow you to clean up. Instead, the Clinton administration forced banks to loan into these areas.
At the same time, more an more money was moving into funds (many of them 401ks) that required conservative investments. AND overall interest rates were continuing to drop. Fanny & Freddie have always bundled loans, but no one wanted A-grade bundles. So, what to do? If you have a bundle of 100 loans, you expect a certain number of defaults. Now, if you write an instrument that pays based on the return of the best 20 of those loans, it's pretty easy to justify rating that instrument AAA. So the conservative funds are happy. Another instrument is based on the worst 20 of those loans. It's going to be BBB, but that's okay, because other people are screaming for high-rate investments as well. They call this "slicing and dicing".
That works pretty well until people start buying the BBB instruments under the expectation that they are as sound as the AAA ones. Which they did. And they did not.
Seriously? Okay, first of all, you don't know what redlining is (or you wouldn't have written "if it was real"), and you don't know what the rules were that were used to lessen (unfortunately, not eliminate) it. Banks were never "forbidden" to loan, they just didn't, because if you let any neighborhood have Black homeowners, then (horrors) the bankers' own neighborhoods would be next. There was always an economic incentive to not redline, but guess what? They did anyway.
So enter the Home Mortgage Disclosure Act, passed by Congress in ... 1975. Hmm, Clinton doesn't appear to enter into it.
And yeah, very much aware of bundling of home loans (how do you think my bank loan wound up with Countrywide?), which reached toxic level in... hmm, the Cheney-Bush [sic] administration. Funny that. No one forced the banks and home loan businesses to go down that path. They did so knowing that they could get away with it. No regulation forced them to make bad loans (the subject in question, despite your efforts to steer it away from that), the banks simply lied about their quality.
Yes, it was a Carter-era law. Clinton stepped up enforcement. And I'm not saying that it never, ever happened. I'm saying that if it was serious enough to merit legislation, then there was a market solution to address the problem immediately available.
The heavy-handed enforcement, well documented, in under Clinton, is what got the game going. The bubble did not burst immediately, it took a decade or so to blow. Yes, it happened to blow under Bush II. You had Alan Greenspan in testimony before the US Congress that there was nothing to worry about. (Which drove me NUTS--my grandfather was caught by the S&L crisis in 1984.)
Restrictions on packaging loans as financial instruments were relaxed. Banks had to hold on mortgages three years before they were rated and bundled. Variable-rate loans were also in play, initially rates (and defaults) tended to be low. I suspect there was some diddling about returns, calculations considering the rates were due to rise without taking into account corresponding increases in defaults.
This isn't an FAA problem, either. If past history is to show anything,
https://en.wikipedia.org/wiki/United_Airlines_Flight_232
it's a casting flaw. Like UA232, it could be from an impure titanium ingot; at these stress levels, even a small amount of impurity, causing porosity, can be deadly. And, unless we develop technologies to inspect cast metals at the close-to-molecular level, we just can't see flaws that fine when originally cast. This is why ongoing inspections are an important part of any critical systems maintenance.
The problem here, according to early reports, is that the flaw starts internally. It could be, for example, a worn mold surface allowing stress microfracture propagation, as you/they can't polish the interior surface of a hollow cast and therefore must rely strictly on the as-cast finish provided by the mold surface.
So there are lots of possibilities of why this happened, the investigation will be ongoing for a while. They will hope to find the initial part that failed in order to give the final word on specifics.
It's true that, when it comes to the engines, Boeing and Airbus are effectively just renting space to the engine manufacturers and the airlines get to choose these.
And, dramatic as both events were, it says a lot about the industry that they weren't worse and that the precautionary groundings* are standard procedure.
* Though I'm sure Ryanair would like to be able to offer passengers to choice…
There was a wonderful documentary several years ago about building RR's latest commercial jet engine. The whole rotating core is surrounded by a titanium cylinder. One of the tests is to have an engine at full speed, and then detonate a charge on a fan blade. It fails if any engine part pierces the cylinder.
The RR engine featured also contains its own telemetry module and communicates directly with RR during flights. This means that the pilots only get told when there is something they need to know, rather than having to monitor the engines in detail themselves.
(I have no knowledge of P&W jet engines, or GE ones either, for that matter.)
That test (and the protective jacket) only applies to the large fan at the very front. The compressor and turbine disks witihin the actual engine core are very difficult to contain in the event of a failure due to their much higher rotational velocities and the forces involved - there have been several examples of a turbine disk exiting the engine casing upon failure and causing substantial damage to the aircraft, eg. Quantas A380 QF32 - https://en.wikipedia.org/wiki/Qantas_Flight_32
and United Airlines DC-10 UA232 - https://en.wikipedia.org/wiki/United_Airlines_Flight_232
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It fails if any engine part pierces the cylinder.
Was that a consequence of the failure of a Trent 900 on Quantas Flight 32?
== Bring us Dabbsy back! ==
Back in the 90s, I saw a DC10 that had a bad compressor stall in #1 on climbout from YYZ. Not sure what was the engine maker. The engine lost blades that went through the power section: That titanium shield was well and truly penetrated in multiple places. There were many holes in the wing fuel tank, so it was dripping heavily.
They were very lucky they didn't have a fire.
>Larger operators tend to buy, smaller ones lease. This is purely because of financing cost, not any technical advantages.
Probably also if you have a legacy of service bases around the world.
If you are a new airline it may be convenient for RR to tell you that next time your aeroplane stops anywhere it will get serviced - rather than having to return it to your base.
This is slightly simplistic: engine (and indeed aircraft) maintenance is entirely predictable, and all airlines very carefully schedule their usage to have the aircraft/engine at the right place at the right time, and the "right place" may be a remote station (to you) rather than a home base. American Airlines, for example, have a lot of maintenance done in Tulsa, OK, even though Tulsa isn't what anyone would call a "base"; what they tend to do is fly into Dallas, and then ferry empty to Tulsa; when the overhaul is complete, guess where the check-flight ends up...?
Of course, if you're a small airline, then you care much more (than the big guys) about emergency repairs (if you have two aircraft, and one is broken, you've lost half your fleet/income. If you have 600 aircraft and one is broken, you've got a few hundred cranky customers).
"This is slightly simplistic: engine (and indeed aircraft) maintenance is entirely predictable,"
Umm, no. SCHEDULED maintenance is entirely predictable. But that is not why the airlines have teams of licenced engineers with the training and experience to fault-find and repair the things that don't go wrong according to the manufacturer's schedule. Even if the Management do seem to consider them an obstacle to making money when they insist on making sure an aircraft is fixed properly rather than being rushed back into service.
this is completely not Boeing's fault.
If the engines Boeing buys from whoever aren't fit for purpose, it's Boeings fault that they fit those engines to the planes, sold those planes with those engines.
Boeing sells the aircraft as a complete package. Everything on that plane is Boeing's responsibility, the flight control system purchased from a 3rd party (Honeywell? Could be someone else), the seats made but yet another company that sells to Boeing, and tyres, the lithium batteries, the sheet metal, the composite ingredients, the bolts, all purchased from 3rd parties, but integrated by Boeing into their aircraft and sold as a complete package. It's all Boeings responsibiliy and fault if it goes wrong.
The engine manufacturer is, like all other subcontractors, responsible for their own products. The primary manufacturer, the contractee, certainly will try their very best to vet any part or device used in their own products, but you can't 100% guarantee anything on planet Earth.
Next, it is not like aircraft manufacturers have much of a choice when they select engines for their designs. Most often, in today's custom-made world, the engines are specifically designed alongside the airframe to match performance and physical requirements. The engine manufacturer can be chosen by using anything from competitive bidding to selecting a company that actually said "Yes" when you asked, instead of refusing the contract. The original engines on the first-generation 747-100's were custom designed.
So it is a complex situation.
The BBC has been reporting - at the bottom of the article, but there since this morning - that "similar failures" have happened with that aircraft and engine twice recently. Quite what they mean by that I don't know, and engine failures are not entirely uncommon, especially if you count bird strikes, but if by "similar" they mean that fan blades have previously failed in the way suspected of happening here (and it seemed to be narrowed down to a fan blade very quickly) then that's more than a little concerning.
M.
RR have had their own problems, especially with the Trent 1000. And there was the Trent 900 (A380) "she go boom" issue in Singapore a decade ago, which very nearly imperilled the aircraft - major damage. Generally I like RR and the XWB (A350) seems to be doing pretty well. But they need to get back into narrowbodies!
Not sure how fire plays out with this (maybe not as much as one would expect, given that I'm sure an engine fire over the pacific ocean half-way to HNL has been considered), but fuel dumping definitely happens for planes whose take off weight is greater than their landing weight or when their nose gear is turned 90 degrees and the plane will come to a stop on its chin.
Given the plane was only going about half its rated distance (pure great circle shit), plus it was less than 2/3 full of pax and this was a domestic flight (less free bag allowances)... it might not have been above its landing weight.
However, I am not sure what the price of fuel is at HNL, and I don't know where that plane was going to next, but it might have been flying with way more fuel than needed if UA wanted to not buy as much fuel at HNL for the next leg.
The final report in 2-3 years will be a fun read, to be sure.
It depends - some flights carry so much fuel that a landing could break the undercarriage and you'd want to dump that before trying to land. On the other hand you may think it safet to be on the ground near a fire engine than fanning the flames at a few thousand feet.
> On the other hand you may think it safet to be on the ground near a fire engine than fanning the flames at a few thousand feet.
Trade off, you don't know that the wing/control surface isn't damaged or that the engine isn't about to fall off and take your wing with it (El Al Flight 1862)
But landing 32,000lbs overweight with no thrust reversers and the risk of over-heating your brakes, bursting tires and starting a fire - is still risky
Denver has really long runways so even without reverse thrust it should be a reasonably good call to turn round and land ASAP. It is all about risk and it is only after the event that it you can, with confidence assess if it was the correct decision.
In this case it clearly was.
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I suspect that this is taken into account when designing the fuel dumping system for modern airlines. If it is necessary to dump fuel with an engine on fire the Venturi's (basically holes used for dumping fuel) should be far enough away from any engine to avoid the possibility of ignition.
I once spent an entire morning colouring in the fuel flow diagram for the Bae 146 aircraft during the design stage. Crayons are also for grown-ups you see.
I saw a documentary years ago featuring Bruce Willis. From that I know that the fuel dump system is initiated via a handle conveniently placed on the edge of the wing. It’s super useful if you’re taxiing through snow and need to dump all your fuel before take-off.
That's dumb, it would be like having an emergency release handle for a nuclear bomb be just where you needed to grab to climb into the bomb bay
True - it's also fair to say that an aeroplane is moving quite quickly, and that any fuel is going to be sprayed *behind* it and move at a similar rate away from the aeroplane.
Equally, so what if the spray caught alight? It would be like lighting a spraying deodorant can - the flame isn't going inside the can.
This is one of the "A" model B777-200s, with a (relatively) short range (basically, good for transatlantic routes, but not transpacific ones). Ranges is a little over 5,000nm, so DEN-HNL at about 3,000nm is no problem.
This particular aircraft is configured for 364 passengers, and there were 231 passengers and 10 crew on board UA328, so not exactly "lightly" loaded, but not operating at max weight by any means!
The B777-200 has a difference of 100,000lbs between max take-off and max landing weight.
UA328 did not dump fuel (total flight time was less than 5 minutes, and they basically just took off, flew in a circle, and landed).
UA328 landed some 30,000lbs overweight on a 12,000 runway (runway 26, as it happens).
This is the second time a United B777-200 has dramatically lost an engine in flight; the other time was 3 years ago, also on a flight to HNL (but from SFO, not DEN). Just like this time, that flight landed safely without further incident. The NTSB finding was that P&W needed to develop a better fan blade inspection. Maybe they need a better better inspection procedure?
Fun fact: UA382 was being operated by line number 5 (the 5th aircraft produced). The replacement that evening that took the passengers to Hawaii was line number 4, which was part of the flight test program (used for things like fuel consumption measurements), so LN 4 was actually delivered after LN 5.
And yeah, LN4 (N773UA) was the aircraft that lost an engine en route to Honolulu back in 2018...
The NTSB finding was that P&W needed to develop a better fan blade inspection. Maybe they need a better better inspection procedure?
The 747 Cargo that had one of its engines go boom the same day was _also_ powered by Pratt & Whitney.
The replacement that evening that took the passengers to Hawaii was line number 4, ...
And yeah, LN4 (N773UA) was the aircraft that lost an engine en route to Honolulu back in 2018...
"The probability that an aircraft will lose two engines is the probability of losing one engine, squared, so it's utterly improbable that such an incident will occur with N773UA a second time."
(The jacket with "How to lie with statistics" in the pocket, thx)
"Maybe they need a better better inspection procedure?"
I caught a bit of CNN earlier this evening and they had an expert on stating that engines and engine parts like fan blade are generally only swapped out if a flaw is found, little or no consideration given to age. Maybe part of the "better better" inspection process is to examine very carefully their oldest engines and fan blades and try to see if there's any correlation between age and likelihood of finding microfractures. Then possibly put flying/running hours limit on some components (if they don't already, the experts implication being that there is no age limit)
With the constant weight reduction, pressure increasing, rpm increasing trend to gain a few percentage points of fuel economy, is this the same problem we are seeing in the auto industry, reducing the longevity of engines?
I know that air travel is still very safe but there seems to have been a few incidents recently that are moving away from pilot and systems error and more into the component fatigue territory.
The PW4000 is a very old design, going back to the 1980s. The 777 variant of it is early 90s, like the aircraft itself. So this is not a cutting-edge engine. Plenty of newer engines have excellent records, including the Trent XWB and the newer GE90s, etc. So overall I don't believe there's any systemic issue with cutting-edge engine tech, at least not yet...
If reports are accurate, two or more fan blades separated from the fan disc and tore a hole (or holes) in the casing and possibly ripping away one or more panels; presumably the passing air then tore away the rest of the casing and then, without anything to hold it on, the front fairing fell off. It does not appear to have gone first - if part of the fairing had failed and had gone through the engine, I would expect more than just two blades to fail, and it would have caused damage to a lot more parts as it went through the rest of the engine.
From the pictures of the one in the Netherlands, it appears to be the front compressor fan which failed - although that is just behind the fairing and the blades would go out and/or backwards, not forwards unless it was a very strange failure indeed.
And most definitely not typical.
Courtesy of VASAviation. ATC Audio + Radar
https://www.youtube.com/watch?v=G7-zh7Sebr8
There is an interesting comment on pprune regarding the video of the engine...
"What struck my phone savvy spouse immediately when watching this video is that although the engine is in rock steady focus, the edge of the window in the picture is moving around.
It is the smart feature of the phone camera that makes it look like a steady view out the window, when in fact the plane and the passengers were bouncing due to engine vibration.
If you don’t believe me, watch the video again and focus your eyes on the lower right corner of the photo which shows the edge of the window. "
https://www.pprune.org/rumours-news/638797-united-b777-engine-failure-5.html#post10995020
Some ambiguous language involved, but I don't think the 777 incident qualifies as an "uncontained engine failure", the 747 incident is.
The 777 engine fan apparently lost one blade, but its energy was contained in the intact Kevlar ring designed for that and the rest of the fan is in place. I don't know if the detached blade fell to earth or stuck in the containment ring but an uncontained engine failure usually means sending compressor or turbine blades hurtling outwards at rifle velocity through the engine housing and containment structures, often shredding the fuselage and injuring passengers - or even damaging critical aircraft systems making control difficult/impossible.
The main engine case is clearly undamaged although something (lubricating oil?) is burning externally on the reverser parts, but the only pieces obviously missing and decorating gardens below are the engine inlet cowl and most of the nacelle: these are aircraft parts, not engine parts... except for the missing blade, but we don't know where that is yet.
Yes the plane would be shaking, the unbalanced fan even at windmilling speed is going to cause major vibration - and it must have been horrendous just after failure at 100% RPM. Possibly the fan shaft back to the LP turbine has been bent as well.
This is a term of art: an uncontained engine failure means that parts of the engine exited the housing. By contrast, a clogged fuel line would result in a contained engine failure.
When UA328 came to a full-stop, parts of the engine were some 16 miles away.
This was an uncontained engine failure!
Not according to some of the commenters in the PPrune thread linked elsewhere, nor to the definitions here:
https://www.skybrary.aero/index.php/Uncontained_Engine_Failure and https://www.skybrary.aero/index.php/Contained_Engine_Failure
From the "contained" failure definition:
"Containment of engine failure — Historical data confirm that turbine engine failures most often are contained. This term means that even if components disintegrate or separate inside the engine, they either safely remain within the engine case or exit the engine case via the tail pipe as intended by the engineers.
This is a standard design feature of all turbine engines. The desired outcome is that the failure of a single engine on a multi-engine aircraft will not present an immediate risk to the safety of the occupants or the aircraft. (Nevertheless, sufficiently large pieces of otherwise safely ejected fragments potentially could injure or kill persons on the ground.)"
Note also that this definition only applies to *engine* parts - any other parts which may fall off as a result of the engine failure (such as the nacelle covers) aren't taken into account when deciding whether it's a "contained" or "uncontained" engine failure.
VASAviation [youtube.com]
Mr Guiani's video should be taken with a grain of salt, relatively speaking it's a minor incident and should not worry anyone. Boeing's stellar and impeccable safety record , and reputation to build great airplanes should have been enough to reassure all the passengers aboard .. < insert Monty Python airplane pilot sketch reference here > https://youtu.be/PktyJR_U2J0 Mine's the one with the built in parachute ..
"As a maintenance guy recently put it, to them the aircraft is more of a formation of valuable components (engines, APU, gear, other swappable spares) held together by the airframe."
https://www.pprune.org/rumours-news/638797-united-b777-engine-failure-5.html#post10994852
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