Given that the aircraft itself seems otherwise undamaged, and people on the ground reported it 'rained' metal shards, I'd say these parts melted off the turbine and fell out. Significant but not catastrophic.
This ended well, fortunately. But that must have been pretty scary.
A 787 that is out one engine will put extra load on the remaining engine, if that one has gone through a similar life as the one that just dropped bits all over the place I'd not wager on the remaining one being as safe as when it was last inspected. That's a lot of eggs in one basket.
And they don't glide particularly well either, though there are some interesting stories around passenger aircraft and glide landings:
20:1 from 3000 meters gives you 60 km to line up and land, that's not as bad as a shuttle but not nearly as good as an actual glider. Personally I'd love to be on the ground in that situation.
You can't just land a 787 on a bit of farmland. BTW if you have to deadstick a commercial plane then the 787 is probably the best, it has the best glide ratio of all commercial planes in service today. But I'd hate for that to be put to the test.
My Cessna T206 has a 9:1 glide ratio, though I plan around 7:1 as I am not a factory rest pilot under ideal conditions. And nothing glides as good as a glider. A 20:1 ratio is exceptional for any airplane, let alone a heavy airliner.
To be fair though, I can safely land a Stationair on 700ft of dirt so my options are a bit better than a 787..
> Shuttle's glide ratio was 4.5:1 - barely better than a brick
A brick has a glide ratio somewhere worse than 1:10; the shuttle (at subsonic speeds) is closer to a sailplane (~40:1, or ~9× better than the shuttle) than a brick (more than 50× worse).
Yep, the 60 km is straight line or nearly straight. As soon as you start to bank and turn you lose altitude faster than the ideal. So the 60 km is a maximum, not a guarantee.
A 787 that is out one engine will put extra load on the remaining engine, if that one has gone through a similar life as the one that just dropped bits all over the place I'd not wager on the remaining one being as safe as when it was last inspected. That's a lot of eggs in one basket.
That's why there are restrictions on which RR engines can be put in a 787 as well as a reduction in the ETOPS certification. There've been a few revisions to the Trent, and putting two of the more "unfixed" ones on one airframe is verboten.
Wow is this really how the industry views it? The notion of having one "less fixed" engine on a twin engine commercial jet aircraft is ok, so long as the other engine is the more fixed version? Sounds incredibly risky.
For such a critical component, I figured they would adopt the military position: "2 is one... one is none".
Not as crazy as you think. We train every 6 months for all types of engine failures. And the plane is required to be able to sustain an engine failure at any point of the flight and still make it safely to an airport with quite a bit of margin, otherwise the flight wouldn't go.
So having one "less safe" engine still means everything is much much safer than the drive to the airport.
> So having one "less safe" engine still means everything is much much safer than the drive to the airport.
That's a statement that I'd be happy to see the numerical support for. To hold the number of fatalities of people driving to the airport in total needs to exceed the number of fatalities as a result of airplanes crashing after one engine already failed on a relative scale, related to the number of people on board those aircraft that had one engine fail.
Keep in mind that the chances for messing stuff up increase once one engine is out simply because all your eggs are in a single basket.
This puts the counter at 43 against. I'm sure that we can dig up other examples. I think one engine out is a sufficient change of the underlying stats that the per-passenger mile quote might no longer be valid.
Of course the other input required is how many planes have single engine failures.
That's a nice solution now that we know the engines need fixing. What about when they were first released? Are planes required to have one old-reliable engine?
If memory serves Rolls placed the blame on the initial problems with the Trent 1000 on air quality in SE Asia (high sulfur content specifically). Which is to say, I don't get the impression that certification was done sloppily.
Are planes required to have one old-reliable engine?
Reliability is (theoretically) improved. From following threads on a.net and pprune it seems like Norwegian actually demanded new engines instead of repaired older ones.
Personally, I'm of the mindset that engines are fantastically safe these days. Piston engines were notoriously unreliable, and even older jet engines were deemed unreliable enough to require more than two for oversea crossings. Look back to when the L-1011 was introduced. It was late due to problems with the Rolls Royce RB-211 (predecessor to the Trent family). Even after the L-1011 began service in-flight shutdowns were pretty common. What we're seeing with the 787 is seemingly less frequent and has provoked a stronger reaction. Of course GE (CFM) isn't immune to problems either and if you look back over their history they've had a few nasty problems including that fairly recent Southwest flight with a passenger fatality.
They are much more reliable, but also much more costly to build and maintain. There was an argument that the A380 wasn't less fuel efficient simply because it had four engines. When you only have two engines they need to be much more reliable, have much higher peak output, and the costs of maintenance are greater. Whereas when you have four engines each engine is cheaper to build, can have more efficient power profiles, and are generally cheaper to maintain. All-in-all it's mostly a wash in terms of cost efficiency.
The argument goes that what killed the A380 wasn't having 4 engines, but having 4 old engines. All the newer planes have engines at least 1 if not 2 generations newer. Notably, the A380 wasn't cancelled until it became crystal clear that engine manufacturers weren't going to invest in redesigned engines. That's when the Emirates order fell through. While their year long dance with Airbus over pricing is what got the most press, it was the backroom negotiations with Rolls Royce that controlled whether the A380 remained cost effective.
I thought A380 was doomed because of lack of configurability for a freight option, and the fact that some narrow bodies were starting to eat it's lunch as direct flights started to become more common instead of hub and spoke.
What you've posted though seems way more plausible though I've gotta admit.
There are many reasons why the A380 didn't have a large market, which would indirectly contribute to its cost effectiveness. But there's a dominant, ELI5 narrative that says that the A380 was intrinsically uncompetitive because 4 engined planes couldn't be as fuel efficient as 2 engined planes. Maybe that's true, but I found the counter argument interesting and persuasive.
> If memory serves Rolls placed the blame on the initial problems with the Trent 1000 on air quality in SE Asia (high sulfur content specifically).
As a related factoid BMW doesn't sell some of its engines in North American, Australian and Malaysian markets due to high sulphur content in the fuel (e.g. [1]). It would be interesting if the same thing happened for aircraft engines and South-East Asian air.
Keep in mind, "catastrophic" is a loaded word in aviation safety parlance. It specifically means that failure of a system or component threatens total unrecoverable loss of the aircraft; and is the point where redundancy and fail-safe become required by law in order to certify.
The regulation specifies no single point of failure should result in catastrophic loss.
Any failure is news worthy, but this poster is on point. Chernobyl meme opportunity aside.
-Not an aeronautical engineer, but I know that a lot of thought goes into ensuring that pretty much no matter what happens to the engine, debris flying from it is not going to damage the structural integrity of the wing or fuselage.
With redundant hydraulic/fuel/oil systems as well, much can happen to the engine without turning the airplane into a brick with passengers in it.
That being said, I am glad I am not on the Trent 1000 design team.
