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E.U.’s Biggest Economies Ban Boeing Max 8 Jets

nytimes.com

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Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#281

Post by namirez »

zanmat0 wrote: post #252
AWildC182 wrote: post #219

Earlier quoted context omitted.

It's a bit more complicated than that even. The 737 was originally designed for a very different mission than it's being used for right now. If you find pictures of the original 737-200s they look very different from the MAX line of today. It was built in an era when it was assumed that 707 and soon after 747 class airliners would serve the hubs and then smaller 737s would serve the small regional airports. As such t…

>if you do as the pilots want and achieve very high aerodynamic stability through the air-frame instead of stability control systems (fly by wire essentially) it reduces the aerodynamic efficiency of the airliner It's crazy to me that that would be an acceptable compromise.

Fly-by-wire means the control surface actuators are connected to cockpit controls electronically rather than with hydraulic lines or metal cables; it's not necessarily related to stability and control augmentation system.

With regard to the other point, I don't think anyone is advocating for very high aerodynamic stability. That would be a B52 carrying nuclear weapons. It was designed to be extremely stable and forgiving. That being said, you don't want to rely solely on stability augmentation for trimming an airliner.

It reminds me of Air Canada flight 143, the pilots lost both engines and power. yet they were able to land the plane safely on an abandoned airport. I'm not sure if that would be possible with a 737 Max.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#282

Post by briandear »

nraynaud wrote: post #185
oppositelock wrote: post #137

Earlier quoted context omitted.

The FAA and Boeing need to investigate this, but you can't make such statistical inferences, since you simply don't have enough data points. There could be no more crashes for the next few years with those 350 planes. The FAA and NTSB are very good at what they do, one of the very few examples of government services that work well together with industry, give them some time.

You just can't have more data points, because flight travel is too safe. And no, the FAA is not really that good, general aviation pilots die all the time from negligence and the FAA doesn't enforce the rules when pilots violate them (in particular low altitude flying).

What’s the “low altitude flying” rule that isn’t being enforced?

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#283

Post by sandworm101 »

namirez wrote: post #281
zanmat0 wrote: post #252

Earlier quoted context omitted.

>if you do as the pilots want and achieve very high aerodynamic stability through the air-frame instead of stability control systems (fly by wire essentially) it reduces the aerodynamic efficiency of the airliner It's crazy to me that that would be an acceptable compromise.

Fly-by-wire means the control surface actuators are connected to cockpit controls electronically rather than with hydraulic lines or metal cables; it's not necessarily related to stability and control augmentation system. With regard to the other point, I don't think anyone is advocating for very high aerodynamic stability. That would be a B52 carrying nuclear weapons. It was designed to be extremely stable and forgi…

Yes it would. There are backup systems to keep things working even with both engines dry (ram air turbine etc). In fact, if you really want to stretch our a glide, all those automated systems are probably a good things. They will keep the aircraft more perfectly trimmed for a glide than the pilots ever could by hand.

https://en.wikipedia.org/wiki/Ram_air_turbine

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#284

Post by AWildC182 »

edoloughlin wrote: post #279
anovikov wrote: post #267

Earlier quoted context omitted.

Obviously stability has to be achieved through fly by wire tech. Doing it through natural aerodynamic stability is a waste of resources of insane proportions as such airframes induce more drag and burn more fuel. If this sounds too scary for people in a forum of software developers it only puts a shame on our profession, from ourselves.

such airframes induce more drag and burn more fuel As a curious bystander, I assumed using fly by wire tech to achieve stability would involve using control surfaces, which increase drag by their nature. How would an airframe that's naturally stable and doesn't require control inputs burn more fuel?

It's more about preventing a stall with a swept wing which is needed to achieve high mach numbers.

That said, an easy (but different) case to visualize is a traditional tailplane. The center of gravity on an airplane is in front of the wing so it wants to pitch down slowly. The tail pushes DOWN in the back to keep the nose up. Nose heavy planes are stable and forgiving but you induce drag because the wing needs to supply some lift just to counteract the tail which is producing negative lift. If you move the CG backward, you get less stability because the airplane wants to pitch up/down more violently with a control input but you have less negative lift from the tail.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#285

Post by pasta »

AWildC182 wrote: post #219
sfilargi wrote: post #146

I urge people to read the discussion by pilots regarding the 737 MAX. https://www.airlinepilotforums.com/safety/120514-ethiopian-7... It all comes down to this: "There are far too many aerodynamic bandaids that are permitted to pass the current standards. Not just this particular airplane, but a whole bunch of airframes. If the basic aerodynamics won't pass without the pushers, pullers and now AOA induced changes to…

It's a bit more complicated than that even. The 737 was originally designed for a very different mission than it's being used for right now. If you find pictures of the original 737-200s they look very different from the MAX line of today. It was built in an era when it was assumed that 707 and soon after 747 class airliners would serve the hubs and then smaller 737s would serve the small regional airports. As such t…

Trump tweeted that planes have become too complicated and that the old and simple form is much better.

His tweet sounds dumb but there is some truth in it.

As you say, planes and procedures have become very complicated. And I think there are only two options: making planes simple again which make them less efficient or let computers fly the plane and make the interface simple(r).

If you look at the rockets of SpaceX then you can say they are the extreme form of fly by wire and very instable when it comes to aerodynamics. But computers can land them within centimeters when they fall out of space.

So maybe that will be the future. Planes that are very efficient instable flying 'rockets' that are controlled by computers.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#286

Post by netsharc »

lgleason wrote: post #248

The FAA has always been very pro-active about grounding planes that are unsafe. The airlines operating these aircraft do not benefit by continuing to fly them if they are un-safe. Between the cost of the loss, public image etc. it would not make economic sense. Given the trade tensions the US has with both China and the EU and the fact that both are offering competing products (Airbus more so), this sounds like more…

To me the more political move seems to be the FAA not grounding them... 2 brand new planes yoyoing after take-off and crashing...

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#287

Post by mehrdadn »

AWildC182 wrote: post #265
zanmat0 wrote: post #252

Earlier quoted context omitted.

>if you do as the pilots want and achieve very high aerodynamic stability through the air-frame instead of stability control systems (fly by wire essentially) it reduces the aerodynamic efficiency of the airliner It's crazy to me that that would be an acceptable compromise.

How so? When I say stability control, we're not generally talking about unstable or "relaxed stability" airframes where the system failing would cause a pitching moment to accelerate rather than converge and the aircraft would tumble and disintegrate. From an efficiency and handling standpoint, this would be ideal, but it's only used in tactical military aircraft where the crew can bail if there's a problem. In most…

> Swept wings are necessary to cruise efficiently beyond ~300mph at high altitude

Layman here, but 737, 747, etc. don't have swept wings, right? So they all cruise inefficiently... but are in fact stable... which is the opposite of what you wrote earlier? Sorry, I'm just really confused.

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#288

Post by [deleted] »

jakelarkin wrote: post #264
sfilargi wrote: post #146

I urge people to read the discussion by pilots regarding the 737 MAX. https://www.airlinepilotforums.com/safety/120514-ethiopian-7... It all comes down to this: "There are far too many aerodynamic bandaids that are permitted to pass the current standards. Not just this particular airplane, but a whole bunch of airframes. If the basic aerodynamics won't pass without the pushers, pullers and now AOA induced changes to…

"the plane should never have gotten the green light to fly." this is an overstatement. airframe fuel efficiency is a undoubtable good thing vis a vis climate change, costs, etc. Obviously they've reached a point were the aerodynamic profile of a modern, efficient airframe is difficult to control via manual pilot input alone in some scenarios. This was the case for stealth technology with fighter/bomber designs.. the…

[deleted]

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#289

Post by balls187 »

mrdodge wrote: post #152
cal5k wrote: post #147

Earlier quoted context omitted.

The 777 is the second-safest aircraft in the world, next to the Airbus A340. The 787 is on track to demonstrate a similar safety record (in terms of fatal incidents). So overall, they seem to be quite good.

Those were produced pre-FAANG, Boeing probably paid comparatively better then. Do the smartest software engineers flock to Boeing in 2019? I think the relatively low pay and status of software engineers outside of the Bay Area is a huge risk to society. We are going to start seeing it show up in interesting places.

Pay is based on market forces, of which, skill is only one factor.

In comparison German Engineers are not paid very well, so do you assume they are lesser skilled than US engineers? [1]

1: https://www.payscale.com/research/DE/Job=Software_Engineer/S... https://news.ycombinator.com/news

Re: E.U.’s Biggest Economies Ban Boeing Max 8 Jets

#290

Post by hindsightbias »

nraynaud wrote: post #185
oppositelock wrote: post #137

Earlier quoted context omitted.

The FAA and Boeing need to investigate this, but you can't make such statistical inferences, since you simply don't have enough data points. There could be no more crashes for the next few years with those 350 planes. The FAA and NTSB are very good at what they do, one of the very few examples of government services that work well together with industry, give them some time.

You just can't have more data points, because flight travel is too safe. And no, the FAA is not really that good, general aviation pilots die all the time from negligence and the FAA doesn't enforce the rules when pilots violate them (in particular low altitude flying).

I would liken GA enforcement to be somewhat like motorcyles. Lots of people die on motorcyles and we see bad behavior all the time, but we don't look at law enforcement and say they're doing a bad job. You're simply operating a platform with a higher probability of death than a car or truck when you do screw up.
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