Commercial jets: where are all the contained engine failures?

General Questions
#1

Yesterday in Denver was the most recent uncontained engine failure to make the news. There seem to have been quite a number of them in the past decade or so.

OTOH, where are all the contained engine failures? A critical part of new engine design/testing is the famous “blade-off” test, in which an engine is operated on a ground-based test stand while a compressor blade is deliberately severed from its hub; the engine is destroyed in the process, but test is considered a success if the engine nacelle keeps any pieces from scattering radially. This is an important safety feature, which would imply that at least a significant portion of engine failures are of a nature that can be contained - yet I don’t recall hearing of many of these. They certainly aren’t as spectacular in appearance as an uncontained failure, but I would still have thought they’d make the evening news.

Is there a stat somewhere? What percentage of in-flight engine failures are contained versus uncontained? For the uncontained failures, how many involve a blade separation that just happened to be unexpectedly energetic (versus a fragmentation of the hub, which is understood to be pretty much uncontainable)?

#2

I’ve been privy to a few over the past 3 decades. They fail, the fan and lower compressor stages and turbine blades may look dog-eared, but no other external damage. The engine is replaced.

They would involve a return to field or a diversion. Tense moments for the passengers and crew, but with fairly uneventful landings. It may or may not make make splashy news.

Visibly shedding pieces, accompanied by flame/smoke or intense vibration. Major national news that doesn’t have to wait for eleven o’clock.

As to the former contained failures, they can include an inflight shutdown ( purposely ) if a parameter or parameters may indicate the continued running may cause a more catastrophic failure. I dare say that other than but for an announcement from the cockpit, an engine shutdown might not be all that noticeable from the average passenger’s perspective.

#3

Pretty much what @BrickBat said. Contained failures are not non-events, but they’re not the large deal. Absent compelling scary pix shot from the cabin, they don’t get much news traction. I can’t readily point to a stat cite, but from background knowledge it’s many, many contained failures for each uncontained. Recognizing contained failures include things like fuel pump failure, where the rotating machinery is totally undamaged but the fire goes out.

As well, the spectacular fanblade-off tests do not prove that uncontained failures are impossible. Merely that one particular (believed to be common) failure mode will be contained. Although it’s becoming apparent that the blade-off test isn’t as definitive as they’d thought. There are a lot of random vagaries in exactly where & how the blade comes loose that impinge on the results.

Southwest has had two uncontained blade-off events that made an absolute hash of the engine cowling. In the first event the shrapnel missed the cabin and most of the rest of airplane. In the second, famously it did not; instead shrapnel busted out a cabin window and indirectly killed the woman sitting adjacent. Plus damaged a bunch of other nearby stuff. Fortunately that collateral damage wasn’t enough to lose the jet completely.

The NTSB (& FAA) are still chewing on these events, but it appears the cowling design has sectors of strength and sectors of vulnerability. If the debris path happens to cut through the sector of vulnerability, the cowling will come unglued and much collateral damage will ensue.

#4

Look up air traffic control videos on YouTube, such as from VASAviation. There’s quite a few engine failures, vibrations, smoke, etc. recorded there, and while they are declared emergencies, most planes end up landing without incident so they don’t make the news.