Boeing 777X: World’s largest twin-engine jet completes first flight
bbc.co.uk
bbc.co.uk
Maximum cargo capacity is roughly three-quarters that of a 747-8 by weight.
There's also a possible 777-10X model that will seat up to 450 passengers and is being pitched as a rival to the A-380 superjumbo.
The real miracle here is that the big four-engine jumbos are being replaced by a twin-jet. (This says something profound about advances in engine technology since 1970. Or even 1990.)
Complete noob here, so I am trying to improve my understanding.
Well that depends what you mean by "need" specifically. The point of being the same type is that regulations-wise they don't.
More specifically, the 737 design had so little ground clearance that the bigger, more efficient engines used in the Max had to be mounted in a different position than before. This change resulted in different maneuvering characteristics that Boeing tried to patch with crappy software. The 777, on the other hand, is a much bigger plane with plenty of clearance and the new engines are only marginally larger than the old ones. I don't see Boeing messing with the engine positioning needlessly here, especially in the wake of the 737 Max fiasco.
Same applies for planes.
Now remember these planes will probably be produced for 30 years, and then maybe in service for a further 20 years. Will you be happy to know that safety critical design decisions were made to standards of 90 years ago?
It didn't have airbags, I was wearing the seat belt, I had a slightly sore neck for a couple months (not like bothersome sore, I noticed it when doing higher impact things).
Which isn't to say I'm opposed to updated safety features, rather that 20 years ago wasn't that bad, even without air bags.
Later models of those cars were improved. But then a similar story happened when the IIHS started testing small overlap for passenger-side crashes, until again newer models were reinforced.
[1] https://www.cars.com/articles/mercedes-lexus-and-audi-fail-l...
[2] https://jalopnik.com/the-toughest-car-crash-test-is-about-to...
I'm not sure why I didn't take pictures of the drivers side, but the front panel wasn't nearly as damaged.
Commercial aviation is one of the safest modes of transportation there is. That’s due to the safety procedures practiced by the operators, not faster FEA modeling. It’s far safer than even the latest cars, when driven by amateurs on public roads.
Is there some specific “safety critical design decision“ you think was lacking in the 777 era?
I don't know what your financial situation is, but I recommend that you research the issue. You can buy a good, safe, and reliable second hand car from a manufacturer like Toyota, Honda, etc.
Er yes I’d be fine with it.
My current car is from 2009, looks and works almost the same as the same model from 1999, and I’m not planning to change it.
Lol I don’t think my 2009 Defender was - doesn’t even have airbags. Pretty sure it has zero crumble zone either. And no adaptive anything.
But I wouldn’t swap it for anything - it’s a timeless heritage piece and represents something about who I am.
One interesting thing about the Beetle is that despite retaining the same basic shape and construction over the entire run a lot changed to significantly improve relative safety: collapsible steering columns, the change to Macpherson strut suspension, door handles with the opening mechanism shielded in a roll-over and so-on.
One of them doesn't even have airbags!
Live a little.
Most of getting licensed is learning how to deal with bad situations. Engine out, getting lost, that sort of thing. Every biennial flight review, at some point, the engine will 'fail'. The plane may or may not belong to the insurance company after in a real event but most engine out scenarios should be survivable. I can't think I've even seen an aircraft that is without 4 point shoulder straps.
Even big stuff can do that sort of landing. (Your call on if you consider that gliding, or just falling with style) https://en.wikipedia.org/wiki/Gimli_Glider https://en.wikipedia.org/wiki/US_Airways_Flight_1549
Sounds like a cool plane though, clearly I appreciate old mechanical technology!
I don't have the numbers handy, but most plane accidents are survivable. In fact, there are many crashes where everyone survived (like the Gimli Glider).
And this issue was already stark on the NG, which had to use these weird flattened turbofan nacelles in order to get enough ground clearance despite its much larger engines:
* 737-NG https://upload.wikimedia.org/wikipedia/commons/c/ce/CFM_56_L...
* 787 https://upload.wikimedia.org/wikipedia/commons/7/70/787_-_Fl...
And even with that they also had to mount the engines way ahead of the wing, clear off of it: https://en.wikipedia.org/wiki/File:N707SA_Southwest_Airlines...
Now this looks a lot like an A320 where the engine is also ahead of the wing[0] but notice how the engine "strut" goes downwards on the 320 but has to "wave up" on the 737NG.
It's very clear on the side-view drawings:
* A30x https://upload.wikimedia.org/wikipedia/commons/9/92/A32XFAMI...
* 737 https://upload.wikimedia.org/wikipedia/commons/b/bc/B737Fami...
where you can also see the side-structure of the original 737 and its low-bypass turbofan (0.96:1 compared to 5:1 to 6:1 for the NG's engine).
[0] https://en.wikipedia.org/wiki/Airbus_A320_family#/media/File...
I believe your picture actually shows the 737-300 (Classic), which had a very obvious flat-spot in it's nacelles. The NGs do also have a slight "flat spot", but it's much less obvious.
https://www.federalregister.gov/documents/2018/05/18/2018-10...
Boeing was required to prove the load-bearing of the hinges on the wings and what types of alerts that the crews receive should a wingtip fail to lock prior to takeoff. More than one means must be available to alert the flight crew that the wingtips are not properly positioned and secured prior to takeoff. If the wingtip is not locked prior to takeoff, the plane is prevented from taking off.
They even required that the electric circuit that unlocks the wingtips be automatically isolated from the circuit that folds and locks the wingtips and that that circuit cannot be re-powered during flight.
ETOPS is the general set of rules for how far a plane with two engines can be from an airport. https://en.m.wikipedia.org/wiki/ETOPS
Four engines just means there's 4 things that can catastrophically fail and potentially damage the plane rather than 2.
The real concern is trans-oceanic long-haul. Supposedly modern engine failure rates have improved to the point that you're less likely to have problematic engine failures than a four-engine 70s-era 747.
I recently rode in a 2-person jet. The pilot said the only reason we might bail out is an engine fire. If the engine fails, the plane's an excellent glider, and we'll glide to an airport/airstrip. Now, this was somewhere with airports all over, not an ocean.
https://en.wikipedia.org/wiki/ETOPS is a good read.
Good to know that the squishy contents of the aluminum can are the least reliable part of the system.
I guess that also limits the size for planes, but probably to 10,000+, so it's not something we're likely to hit.
Say that you need 50% of the engines on the plane to be able to fly safely, then having more engines is actually safer. For example, supposing that engine failures occur 1% of the time, with four engines there are 3.97 three and four engine failures per million flights. For a two engine plane, there are 100 two engine failures per million flights.
There's probably less drag from two engines than four as well.
That's what I meant by "collateral damage".
Doubling the number of engines doubles that risk.
On the other hand, a failure that would take out both engines on a twin jet is likely to take out 4 engines. Failures such as running out of fuel, ingesting a flock of geese, and ingesting hail.
The rational justification is not merely technical but rather empirical, proven by real-world data. Certifications usually because companies can demonstrate e.g. "N years of trouble-free XXX-minutes ETOPS experience". In other words, we've been doing it for this long and it works so there's statistically ever-less reasons to believe the certification is flawed.
So, despite all the stats you may collect about birds, and physical + ethological models to estimate how much chance there is it will happen twice to a twin engine plane on both reactors before it can land, it would only prove reality: it just doesn't happen. Or not in ways that more engines would solve. (Birds are a bigger problem for cockpit windows, though.)
Now, another additional bit of safety: all jetliner planes have a "fixed-wing" design, allowing "deadstick landing"². From wiki:
> All fixed-wing aircraft have some capability to glide with no engine power; that is, they do not sink straight down like a stone, but rather continue to glide moving horizontally while descending. For example, with a glide ratio of 15:1, a Boeing 747-200 can glide for 150 kilometres (93 mi) from a cruising altitude of 10,000 metres (33,000 ft).
More recent planes are usually ever better (the OG 747 is from 1969!) At the very least it allows the pilot to 'land' on sea and wait for evacuation in zodiacs. So even in the extremely unprobable event that ETOPS failed (the statistical outlier where a plane loses both engines), you'd probably just glide to the ground 100-200km away at most to reach some landing spot.
There are reasons why air travel is so safe, the safest of all, and most of those are empirical, real, tested then validated. That's why it was such a shame what Boeing did to the 737 MAX; and I hope the 777X program yields the safest planes we've ever seen from them, that they actually innovate in that respect.
Safe travels!
While I agree with the rest, landing on sea is a terrible idea. That can work on rivers where you have no waves. But gliding onto an ocean with waves will likely be fatal. Luckily, there is no recent case of a double engine failure where landing on sea was necessary (apart from maybe MH370 but we don't know that).
The main argument was really about not dying from engine failure (i.e. from falling) since planes glide — knowing this totally changed my impression of "safety" wrt riding planes, for the better: “planes can't fall!”.
Interestingly, most of that article is about the 737 Max issues (the MCAS software is a disaster, it's a push to even call it engineering).
As best I can tell, CFD is still kind of like impedance-based home body fat scales. They're kind of directionally accurate but have a pretty high error.
I thought CFD would be a solved thing by now, but then I remembered how good (e.g. bad) weather prediction still is.
Some people think that wind tunnels will be obsoleted by computational fluid dynamics within the decade. Others think that the problems with CFD are not a lack of compute power but a lack of comprehensive understanding and modeling of the physics at play, and expect that wind tunnels will be with us for quite a while. (Personally, I believe in the progress of technology and expect an eventual if not near-term breakthrough in CFD software will eventually obsolete the wind tunnel, but I also think that institutional inertia will keep a lot of wind tunnels and businesses that purchase time in them in operation for a decade or more after CFD's big breakthrough...)
https://en.m.wikipedia.org/wiki/Computational_fluid_dynamics
“21st Century Jet” is a documentary about the building of the 777. Looks like it’s available on YouTube.
https://www.seattletimes.com/business/boeing-aerospace/massi...
The wings are assembled horizontally similar to the to A350.
Is that related to the recent MAX issues, or to the fact shipping such a large aircraft on two engines only was much harder than expected?
It needs no new special handling compared to the existing 777, which already had a higher amount of airports available as destinations, if only because it didn't need two-level tunnels for speedy embarkation/disembarkation.
Also, 777 has always served the long distance market, and this plane is essentially an extension for it without many of the downsides of both A380 and 747
https://leehamnews.com/2020/01/25/third-time-is-the-charm-77...
Has Boeing learned anything from the past 12 month ?
The core difference is that even the original 777 is a Fly-By-Wire system with programmed behaviour, in fact it was a well known case study in building civilian safe FBW systems.
Because of that, there's no need to "patch over" differences like it was done with MCAS, as the minute adjustments can be done across the whole flight envelope protection system that is already there since first 777. In fact, 787 controls are derived from that and use software adjustment extensively in order to make control surface generate less drag yet still be usable.
Just the fact that these planes are getting longer and longer will have some side effects on how they handle. Maybe more caution is required when taking off, maybe the body vibrates very differently. While weight may be the same it is also further out which changes the handling dynamics. These make be small matters which may not matter until they do.
Compare this to the 737 MAX which still relies on mechanical linkages and two different flight computers with the pilot supposed to be the safety when they disagree, there any change introduces differences in the feeling and handling at the pilots hands.
Question Boeing's recent engineering and similar all you want, but this is completely different.
Besides, the 777 wasn't designed for low loading at small airports.