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Comment by kijin | Hacker News Reader

Yeah, Boeing gets (and rightfully deserves) a lot of flak these days but updating the 20-year-old 777 is very different from updating the 50-year-old 737.

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.

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> 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.

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...

"the NG, which had to use these weird flattened turbofan nacelles in order to get enough ground clearance"

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.

There is a similar example for the 777X though. The new folding wingtips to fit into the existing gate sizes seems like a potential new failure mode like moving the 737Max engines forward. No evidence it won’t work fine but it feels like a hack.

Here's a link to the FAA certification for the folding wingtips. It's pretty comprehensive.

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.

Did they show simulations about what would happen if they fold during flight? Is it just rougher flight with less lift or would they severely impact the pilot's ability to steer the plane?

That’s closer to the type of iterative change one might expect from a new model of the same type. As long as they’re structurally sound, the folding wingtips present more of a maintenance risk than a safety risk.

why don't Boeing leave wingtips vertical like on A350 or 737? A feet of vertical winglet replaces 3 feet of horizonal wingtip. So with 3 feet high winglets Boeing cold have just avoided the need for folding.

vertical winglets are ways to get more lift:drag out of a wing that's constrained by some width limit (airport gate spacing) or an existing wing design that you don't want to redo. they don't generate lift. for a clean sheet design you can do better with a "scimitar" wingtip that actually provides some lift and might weigh the same as a winglet. see 787. also the navy p8 which has the most efficient wing of any existing 737, and doesn't have vertical winglets (because it doesn't typically park at a gate they could go wider with these little triangular extensions)

If the cultural problems at Boeing led to the issues with the 737 then perhaps they would also manifest themselves on this plane, just in some other part of the aircraft.

The 777 is also FBW. They wouldn't have needed the patch. It'd just be a change in how the stick forces are mapped.

Technology dramatically changes in 20 years. Would you be happy to drive around in a 20 year old car design? I for sure would feel a little uneasy about the rather basic airbags, and the lack of proper FEA modelling of the crumple zone.

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?

I crashed a gen 2 Ford Explorer (first production year 1995) head on at about 35-40 MPH and wouldn't be scared to drive one around today. The other driver crossed the centerline directly in front of me and I crashed into the rear of their gen 2 Ford Explorer (so a medium-large vehicle striking a medium-large vehicle).

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.

A head on crash is very different from an offset crash, which are supposedly much more common, and much more likely to cause injuries compared to a full head on crash where forces are (relatively) easier to be dissipated. When the IIHS started testing small-overlap crashes, many vehicles failed, receiving a score of "marginal" or "poor", including cars such as the c-class.

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...

It was somewhat offset: https://imgur.com/a/I8YxrAt

I'm not sure why I didn't take pictures of the drivers side, but the front panel wasn't nearly as damaged.

Glad you're safe, but look up the IIHS medium and small overlap tests to see what those overlap tests look like.

OT: I would also prefer a 20 yr old car design then a modern 'smart screens everywhere let the car drive for you because it is safer'. Cars were just finoshed back then, but in comes the age of 'Everything as a service'. Cars today are crap. Maybe in another 20 when they fix the batteries.

I drive a 23-year-old car design and have zero qualms about it.

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?

Newer cars are provably much safer compared to older models. They have both active safety systems, such as pre-collision braking, lane tracking, etc. as well as passive systems such as airbags and superior crumple zones. Not to mention they're much more efficient when it comes to fuel consumption.

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.

My 25 and 30 year old cars don't fall out of the sky if the engine stops working, and even if I do wreck I'm not looking at guaranteed death like that in a typical plane accident.

One of them doesn't even have airbags!

Live a little.

Good lord... I realize my plane is 64 years old now. I was able to solo with about 8 hours of training (a few takeoff and landings by my lonesome).

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

Sure, I was being hyperbolic. But all of those are emergencies that require technical training and a cool head to evade - and not everyone is capable of flying a plane. Contrast that to a car where the worst that can happen is you roll to a stop. Hell, during near misses, you can panic brake and lock the steering wheel and that's it, your ride is safely over. No need to hit a runway with just enough glide left within a speed range with some special configuration of control surfaces.

Sounds like a cool plane though, clearly I appreciate old mechanical technology!

> I'm not looking at guaranteed death like that in a typical plane accident.

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).

> Would you be happy to drive around in a 20 year old car design?

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.

Just because it looks the same, does not mean that it's the same under the hood. Designs are constantly improved and re-worked for safety. Look up what happened when the IIHS introduced the small overlap test. Several manufacturers (including luxury brands like Mercedes-Benz) failed the test before re-enforcing the same design to make it pass. Not to mention active safety systems such as pre-collision braking and the like, which don't exist on older models.

> re-worked for safety

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.

I've a Defender, a '66 VW Beetle, a Fiat 500 and a Volvo XC40 with adaptive and predictive everything and I'll only take my kids out in the latter. Heritage vehicles have their place but they're harmful to the occupants and harmful to the other party in an accident. I wouldn't use one as a daily for that reason.

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.

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