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Korean Air, Asiana to ground Boeing 777 after engine incident (koreaherald.com)
155 points by dlcmh 8 days ago | hide | past | favorite | 102 comments

Specifically, it concerns some variants of the Pratt & Whitney PW-40xx engine (the affected model was a PW-4077). Japanese carriers also grounded their affected planes earlier, and so did United.

Japanese authorities issued a NOTAM requesting airlines not to fly the affected planes over its territory. The US FAA is about to issue an emergency directive soon but only expected to decrease the inspection intervals of the affected parts rather than ground the planes completely.

The Aviation Herald has all the updates: http://avherald.com/h?article=4e35503b

CNN for comparison focused on "right engine failures" rather than engine type, citing 2 failures in three years. In related news, for two coin flips there's a 1/4 chance of two heads in a row.

To be fair they did mention that the engine type was the same, along with the fact that both aircraft were headed for Hawaii.

[1] https://www.cnn.com/2021/02/22/us/united-airlines-2018-engin...

Korean Air had a similar incident in 2016 where a PW4000 on a Boeing 777 disintegrated during takeoff.


...Decrease them to zero, aka ordered an immediate inspection.

The fan blade had a stress fracture. So they'll need to do an immediate ultrasonic scan of the blades, which should clear the engines for flight, and then figure out why the maintenance schedule didn't catch the fracture.

Which, to pinpoint the insanity of the FAA, the failure seen over denver actually involved an uncontained blade exiting the engine, something it was clearly not designed to allow to happen. It's a mess.

But the engine did contain the failure. No pieces of the engine caused any functional damage to the rest of the aircraft. The housing is designed to prevent shrapnel damage, not to prevent stuff from falling out altogether.

What's insane about the FAA's approach? They are ordering immediate inspections of all fan blades in these engines for cracks like the one that apparently brought this one down.

Not fully contained. See https://twitter.com/breakingavnews/status/136379347594735616... for damage to wing to body fairing.

There certainly was shrapnel damage to the plane. http://avherald.com/img/united_b772_n772ua_denver_210220_8.j...

Contained vs uncontained turbine failures relate to the damage from the blades being contained, which in this case they were. Contained failures still result in engine parts exiting the engine, but not through the engine case, which is reinforced to contain the turbine blades in a failure. The unexpected issue here is that the cowling was knocked off, which is not supposed to happen, but in recent years it seems to be happening.

It was not contained. A blade went though the lower wing root.


decrease? increase?

Decrease the interval, increase the frequency.

As a non-native I would've used `increase the interval` -- but I understand now this is incorrect. TIL..

> As a non-native

i am a native and this confuses me constantly.

the windshield wipers in my car change their speed based on a UX showing an in increasingingly long bar. i can never tell if it represents time or 1/time until i futz with it.

>> UX showing an in increasingingly long bar

I have driven car where the pictogram meant "amount of rain", the longer bar meaning more rain and therefore a shorter interval.

Huh? The lowest setting (the one closest to off or auto) is the one for the least rain, and it goes up to handle more rain, i.e. the further you are from off/auto the faster the windshield wipers wipe.

> Huh?

Yes, you are right to be confused. You dont know the UX of car. Why did you think this was worth commenting?

> (the one closest to off or auto)

the on/off toggle is separate from the speed dial. there is no obvious (to me) directionality.

Only on hacker news can a discussion about an airplane engine end up about windscreen wiper UX.

Yeah that's one thing European cars do wrong. They have two separate controls: one for on off the other one for interval.

American cars in contrast have just one control: it starts with off, then does intervals, finally the shortest interval, then low speed and then high speed.

I’ve been living in Europe for a couple of decades and I have never seen a on/off control separate from the speed.

Welcome to downvote hell with me. God damn, sanctimonius know-it-all HN jerkoffs do piss me off (yeah, go ahead reader, downvote me).

But your classification of European/American cars isn't accurate either. I drive an Italian car (well, but surprise, it's Fiat Chrysler) and the wiper controls makes sense, like what you refer as "American cars". Search for Mercedes Benz wiper controls on Youtube, that also makes sense. BMW's one is strange, the Ford one looks confusing but I didn't bother to look for a video.

indeed, it would have been clearer to say 'increase the frequency of inspection'

My bad, I could have worded it clearer: "have the parts inspected more often" would do, I think.

Alas, can't edit the comment anymore, and probably shouldn't anyway, considering the discussion it sparked.

sorry for nitpicking, but as a non-native speaker I can understand the confusion

If it counts only time on air, can we call it wavelength?

Thank you. I'll show myself out.


When inspection frequency gets too low, airplanes fail, leading to more frequent inspections.

When inspection frequency gets too high, airlines and authorities decide to save money, leading to less frequent inspections.

So the inspection schedules (somewhat) satisfy Hook's Law, and thus we should expect wavelike oscillations.

[Edit: The system also requires momentum. That's provided by labor unions agreements, maintenance contracts, and the time needed to change regulations.]

Thanks, I'll be waiting for you at the pub.

>> When inspection frequency gets too high, airlines and authorities decide to save money, leading to less frequent inspections.

More often such aircraft are just retired. One defining difference between upstart airlines and "legacy" airlines is that the upstarts generally have new aircraft with lower inspection requirements. An interesting paper would address the inevitable evolution of new airlines as as their airframes age. When do they first try to transition to higher-profit services? When do they hit their first period of labor unrest? I theorize it is a function of aircraft age.

At least a few airlines don't ever buy aircraft. Instead they lease them with the intention of returning them moment they require more frequent inspections.

Upstart airlines frequently lease used aircraft because they're cheaper.

This whole business is so capital-intensive the decisions often follow non-obvious patterns. There are advantages in keeping a fleet uniform, even if a newer plane lease is cheaper than another model you already have a bunch of just because of the costs of training ground and air crews. Some leases may end up cheaper for you - and only for you - because of some tax break you got from one government that, for now, wasn't questioned by the WTO (and, since it's the manufacturer who'll pay the fines, it's not a concern).

It's... complicated. Very complicated.

We should write a paper on this. I know quite a few (dis)reputable journals that would readily take it.

When the interval decreases the frequency increases

According to the BBC article at https://www.bbc.co.uk/news/world-us-canada-56149894, "Boeing has recommended grounding all 777 aircraft with the same type of engine". So this isn't just a few airlines or an individual country.

Checks stock. Only down 2.0%. The current nutty index fund driven stock market, folks.

Which stock? P&W? Airlines? Boeing?

Boeing doesn't seem to be at fault here. The particular engine is from P&W and they make engines for Airbus and others as well. I can't see how any of this should be extremely negative long term for neither boeing or P&W.

This sort of thing isn't good news, certainly, but it's not that exceptionally bad, either. This sort of thing is happening on a low level all the time, it just doesn't always make the non-aviation news.

Given that the problem is with the engine, which Boeing did not build, why would Boeing stock be down?

Fun fact: United Airlines, Pratt and Whitney, and Boeing used to all be the same company. They were forced to break up after the Air Mail Scandal:


United Technologies is the result of the manufacturing interests east of the Mississippi and Boeing got everything west.

Indeed, 88 years ago Boeing made an agreement with the US government not to make certain aircraft parts (engines mostly) and not to operate any airlines. Those ugly freighters they built for the 787? Flown by Atlas Air.

Because people like GP see "Boeing" and "engine failure," assumes Boeing was at fault, and sells or shorts. It makes sense if you don't realize Boeing doesn't make the engines for these planes.

Are you saying grounding Boeing planes is GOOD or neutral for Boeing, but definitely not a negative?

Trading sets prices, not AUM. Index funds do less than 5% of trading. 95% of trading still happens by active investors. So it's active investors who've decided that Boeing is worth 2% less than yesterday. Index funds have almost nothing to do with that.

There are a total of 69 of these planes in service worldwide, and another 59 in storage.

Why would you expect grounding 128 planes, nearly half of which weren't even being used, due to a problem with a part that Boeing doesn't even produce, to affect Boeing stock?

Boeing has already been beat up a lot of past plane groundings so I’m not sure an issue out of their control would do much.

It just sucks for them to be in the news again for airworthiness. I might considering investing in them right now to be honest.

They'll check the engines for a specific defect and have them back in the skies in a few weeks.

Technically they’re grounding the Pratt & Whitney engine model that happens to be attached to their aircraft.

When one buys a big jet you pick out what engine you want to buy and slap onto it. It’s a particular engine they’re concerned about, not the 777 airframe itself.

That's a good point.

As far as I know, newer B77* generally use GE or RR engines. The PW ones are old at this point, and also represent the smallest and decreasing share, so most planes of this type aren't affected. United (or one of its predecessors) was an early customer, and I think PW was the only engine option at launch.

(Not my area of expertise, so I'd appreciate a correction if I got something wrong.)

Pretty much correct. The Pratt engine was in service six or so months before the GE engine (and a year or so before the RR), and United was the 777 launch customer.

The only thing is that the newest 777 variants (777-200LR and -300ER) only offer GE as an engine option, there isn't even a RR choice.

The P&W-powered 777 is just one variant.

British Airways for example went with GE90s, and some airlines like El Al went with Rolls Royce Trent 800s.

Are there any Airbus (or other comapanies’) planes that have the affected engine? Or just Boeing?

Airbus A300-600/A310

Airbus A330

Boeing 747-400

Boeing 767/KC-46

Boeing 777

McDonnell Douglas MD-11

...however the exact type of engine Boeing is using for the 777 (PW4000-112 - https://en.wikipedia.org/wiki/Pratt_%26_Whitney_PW4000#PW400...) is not used by any other airliner. I'm no expert, but as the most powerful -112 version has almost twice the thrust of the -94 version, I wouldn't automatically conclude that problems with one type mean that there are also problems with the other types. OTOH, if they take a closer look at the 777 engines and find a lot with problems that went undetected until now, I assume the other PW4000 engines will get a closer inspection as well...

Its noted that a 747 had a very similar issue the same day as this 777 with the same series of engine.

Since the issue is most likely with fracture detection during maintenance inspection and P&W introduced new procedures for that a few years back, its likely the issue is with the tech being used or the procedures. Which would mean any P&W engines using the same technologies and procedures to detect fan and turbine blade cracks would be affected.

The core is the same. The different model numbers typically represent other configurations of the stages or pump throughput, type of FADEC, and all of these things.

That seems like a complicated way to sell airplanes - why is that ???.

It is like me buying a car from Ford and saying I don't want the Ecoboost turbo 4 but rather that V8 from the Raptor.

Most car models come with various engine options, sure you can't get a V8 in your focus but you can choose between various displacement Gas/Diesel/Hybrid options. In fact the current model year ford focus ships with 14 engine variations.

It’s a standard thing in aviation. The companies that make “airplanes” are usually not the ones that make airplane engines that go on those planes. For big airliners the engine makers are GE, Rolls Royce and Pratt and Whitney. Same concept applies to small general aviation aircraft where the two big engine makers are Lycoming and Continental Aerospace.

The engines are still type rated for the specific aircraft. Some aircraft might only have one engine type rated so there isn’t much choice. Others might have multiple engines to choose from, from multiple manufacturers. That’s the case with many commercial airliners.

One of the answers [0] on that page even discusses the next step in decoupling airframes from engines - sorry, I meant decoupling their supply: Power Generation as a Service complete with on-demand billing and feature locking. It's not well sourced, nor highly upvoted, but fascinating if true.

> These days, the engines are often leased, not bought, as part of a "power generation package"...The only physical difference between two "different versions" of a particular engine type, with different advertised power ratings, may [be] the electronic engine control system. In that situation, the airline might negotiate a "total power generation" deal where they only pay for the "higher rated" engine when they actually use it.

[0] https://aviation.stackexchange.com/a/38196

Used to work for a bank many moons ago and we bought a new mainframe (Unisys) and few months down the line we had major month end batch processing issues.

So they payed Unisys a not so small chunk of money to "unlock" the second CPU board which was always present inside the mainframe that was installed.

As a PC guy I was gobsmacked.

It’s actually antitrust at work - United Aircraft and Transport Corporation was split in 1934 into Boeing for airframes, United for airline, and holding called United Aircraft Corporation that owned Pratt & Whitney for engines.

There are a number of reasons - but one is that some AIRLINES will prefer to stay with an engine manufacturer across all their planes if at all possible, as it reduces maintenance training and headaches.

Many boats are the same way. You buy a hull and then mount whichever outboard motor you want.

This might be due to a car being a more common retail purchase compared to a plane. Airlines might want to customize their plane for the usage and different engines might provide different benefits.

I’m guessing it has most to do maintenance training and supply chains.

If x carrier standardized on PW or Rolls engines, it makes sense to try and keep their fleet on that engine. It simplifies maintenance, what parts need to be kept in stock etc.

If you have a fleet of rolls engines and one batch of planes running PW then you have to set aside entire storage, training and supply chains for a single batch.

From Boeing’s perspective, they can sell more airframes with a modular setup that allows the carriers to choose their powerplants. Especially in a worldwide setup where a rolls Royce may be cheaper in one market and a PW cheaper in another across a pond

Cost, supplier redundancy, antitrust laws

These kinds of systems do allow for corruption of course [0].


[0]: https://www.bangkokpost.com/thailand/general/1181845/rolls-r...

Also, this is not the first incident and it it's not the first Airworthiness Directive against the PW-4077.


While I understand the point you're trying to make, I'd just like to note that if you type any mature engine for any aircraft into a search engine, you're going to find more than one Airworthiness Directive for that engine

No point really, just interesting that they've had an eye on various metallurgy inspections for a while.

This is at least the third engine--with Trent and GE--so maybe those guys had their share of AD's. Also props to the 777 platform for being modular here and bulletproof in general.

edit. It's obviously a tradeoff of accepting a certain number of (usually) contained survivable fan events vs being able to afford flying them.

>>It’s a particular engine they’re concerned about, not the 777 airframe itself.

While literally true, in all practical terms those airframes are grounded. Engines can be swapped but it isn't as simple as swapping a V8 for a V6. These are expensive and physically large objects. There aren't enough spares available to re-engine so many airframes, and it would take years to build a new supply. So any airframe with the listed engines is essentially grounded until the problem can be addressed.

Only the 777s that have PW4000 engines. The 777s with GE or Trent engines are fine.

That’s only about 60 in service planes.

Try ordering 120 new airliner engines. It will take a while. There is no real surge capacity for these things. You would probably have better luck buying used.

Maybe. But most airline companies can ground a small portion of their fleet and it not really affect their outcome. They should have some redundancy built into their maintenance schedules so that 60 planes, even in a single company shouldnt have too much of a flight schedule burden.

On the same day as the US incident there was a similar (but less spectacular) failure with the 747 in The Netherlands:


I don't know if being pelted with ninja throwing stars from the sky is less spectacular, maybe because there's not live footage.

More importantly, it seems it's a variant of the PW engine of the 777

The chance is small (though big enough to be considered), but they could be related

An incident related to a Bermuda airline taking off from a Dutch Airport, yet they are using Air China cargo as a picture? SMH.

TL;DR: parts dropped from a burning engine just after take-off from Maastricht-Aachen Airport, causing damage and injuring a woman in the nearby town of Meerssen. Plane landed safely in the next city over.

From another news article:

> Dickson said that his team has 'reviewed all available safety data following yesterday's incident,' and 'based on the initial information, we concluded that the inspection interval should be stepped up for the hollow fan blades that are unique to this model of engine, used solely on Boeing 777 airplanes'.

> hollow fan blades that are unique to this model of engine, used solely on Boeing 777 airplanes

Hamilton Standard fan blades used to have cracks that went unnoticed during rebuilds because of faulty inspection and repair procedures. This caused 3 accidents including this one in Georgia - https://en.m.wikipedia.org/wiki/Atlantic_Southeast_Airlines_....

I can't help finding this a bit ironic, given that the B777 is an amazingly safe airplane with only 8 hull losses out of over 1600 built (so less than 0.5%), and one of those hull losses was because an Asiana crew "landed" a fully functional 777 on a beautiful sunny day short of SFO RW 28 L [1].

The other 7 hull losses were

* a BA flight landing short of LHR due to iced up fuel [2],

* Emirates crash landing in Dubai due to a botched go-around [3], and

* two Malaysian Airlines flights that had nothing to do with the aircraft (the probable pilot suicide/mass murder of MH370, and MH17 shot down over the Crimean), and

* three aircraft burning out on the ground (EgyptAir, Singaporean Air, Ethiopian).

Amazingly, there were only 3 fatalities with the Asiana crash (two not wearing seatbelts, one run over by fire truck), 1 with the Emirates crash (firefighter, not passenger), and 0 with the BA accident.

Only the BA flight really revealed a problem with the aircraft which appears to have been fixed.

[1] https://en.wikipedia.org/wiki/Asiana_Airlines_Flight_214

[2] https://en.wikipedia.org/wiki/British_Airways_Flight_38

[3] https://en.wikipedia.org/wiki/Emirates_Flight_521

I asked my aircraft buddy about this. He mentioned that it wasn't a GE engine, and that he doesn't even know what his GE rep looks like because of how few issues they have. Must be a big issue with P&W engines.

"If it says Pratt and Whitney on the engine, it better say Martin-Baker on the seat!" -Unknown

(Martin-Baker is an ejection seat manufacturer.)

I was curious, so...

The quote may be from the 1970's, associated with the F-14, its troubled placeholder P&W TF30 engine, and maybe then early TF100 problems.[1]

Brief googling does not suggest P&W airline engines are atypically problematic.

But the engine technology envelope has historically been an aircraft bottleneck, and therefore pushed hard, with associated failure. Thus the quote. And China's ongoing difficulty manufacturing airline engines. Which remain challenging[2].

> Powerplant makers face conflicting demands for performance, reliability and huge production rates [...] “I’m a little bit irritated that over the years we as an airline, and the industry, have been subjected to the requirements of the propulsion manufacturers, and to an extent the airframe manufacturers, where we are expected to deal with quality-control issues, design issues etc, and operate these aircraft and engines and take whatever consequences there are when they don’t work,” [2](2019)

[1] https://www.google.com/books/edition/Storm_Over_Iraq/DqaZBwA... [2] https://www.flightglobal.com/strategy/everything-you-need-to...

The superstitions of fighter pilots are not always based on hard science...

The engine is PW4000-112. It's the largest commercial PW engine. It has 112 inch, shroudless, hollow titanium fan blades,

A passenger photo appears to show exactly this: one blade missing entirely, the adjacent blade broken about halfway.


> and canned a number of programs

What programs?


If you are actually convinced of this to some degree, you might want to see a doctor as this sounds a lot like paranoia and/or schizophrenia.


Despite all this news and previous problems, the stock price keeps rising. How and why??

Raytheon Technologies Corporation (NYSE:RTX), the parent of Pratt & Whitney, is down 2.9% pre-market?

And The Boeing Company (NYSE:BA), in terms of knock-on effect, is down 3.9% pre-market?

Hard to say it's related to the grounding of the planes, futures are down which commonly means the market is going to open overall lower. currently down 0.5% - 1% which is pretty large.

> The Boeing Company (NYSE:BA),

Not to be confused with BA the airline

Which stock price? The 2 airlines? Boeing? The engine manufacturer (P&W)?

It’s 60 active airplanes, solely operated by United in the US and some others outside the US. Seems like a smaller problem than the 737, and this doesn’t seem to be Boeing’s fault.

I wonder if this incident was the result of the plane being in storage for an extended amount of time and recently returning to service.

These Aircraft are designed to be in flight constantly maximizing revenue. With the pandemic grounding so many planes for such extended amounts of unplanned time, I wonder if we are beginning to see gaps in maintenance procedures for aircraft returning to service after extended downtime.

There’s no reason to suspect this was an issue here, it doesn’t really have any connection to what’s happened or how airline maintenance works.

And the engine comes apart after not being in use for a while? Scary

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