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Would you fly on a Boeing 737Max?

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scosutsut

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Correct. For whatever reason, they neglected to use both.
Throwing out decades of painful learning about the need for multiple redundancy on critical aircraft componetry and it's the point that it went from debatable but probably defendable decision making to the inexcusable.

So when you compare the Comet and Max situations you have:

An unavoidable mistake fixed by engineering but the aircraft's popularity and usage doomed by reputation

Versus

A completely avoidable mistake fixed by a bodge and yet people are still defending the aircraft's reputation!
 
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Bletchleyite

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Exactly Comet 4 had the physical defect removed, Max hasn't.

Sort of. MCAS is there to make it handle like a classic 737. It would still be aerodynamically stable even with it removed completely, so the fundamental design isn't defective, it's just that they wouldn't have sold as many if it required a different type rating, as if you're going to require that there's all of a sudden no downside of going with Airbus instead if that's cheaper.

Surprised the 787 has it at all, what purpose does it serve there? Surprised the 787 isn't fly-by-wire (in which case the handling characteristics are entirely in software anyway), but then this is Boeing we're talking about :)
 

Bungle158

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Would l fly in the Max? Not unless l was desperate. As an average Joe punter, in my mind, the Max is a 55 year old airframe concept, with overlarge engines and bits of software, designed to keep the thing from falling out of the sky, soldered on. Call it gut instinct, but l don't trust it.

The 787 is ok internally, although as with all aircraft, much depends on cabin configuration. There are though, disturbing reports about build quality.

I regularly do 25K miles plus a year, and tend to favour Airbus equipped carriers. The 320 family is a much newer airframe concept, with a great safety record. The A350 flights l have taken, Ethiopian, Iberia and Qatar have all been fab experiences. The A350 offering from these carriers certainly seems at least, to be superior to the Dreamliner.
 

Bletchleyite

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Would l fly in the Max? Not unless l was desperate. As an average Joe punter, in my mind, the Max is a 55 year old airframe concept, with overlarge engines and bits of software, designed to keep the thing from falling out of the sky, soldered on. Call it gut instinct, but l don't trust it.

MCAS is not "designed to keep the thing from falling out of the sky", it's intended to modify the control inputs so that a Max handles the same as a classic 737, allowing it to be flown on the same type rating*. Even were it not present at all, or disabled, it would not "fall out of the sky".

* For the unfamiliar it's a bit like signing a specific class of unit on the railway, but generally a pilot only "signs" one type of aircraft to avoid confusion, so you can understand why airlines like the idea of this.
 

scosutsut

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Sort of. MCAS is there to make it handle like a classic 737. It would still be aerodynamically stable even with it removed completely, so the fundamental design isn't defective, it's just that they wouldn't have sold as many if it required a different type rating, as if you're going to require that there's all of a sudden no downside of going with Airbus instead if that's cheaper.

Oh, thanks, I'll need to do some more reading up
 

Ted633

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As far as I'm aware, the 787 doesn't have an MCAS. The stab and elevators do work together much more than on previous types though. When you pull back on the yoke, the elevators will move for the first 2 seconds, then the stab will take over as the system sees it as a long term pitch input.
 

Bletchleyite

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Oh, thanks, I'll need to do some more reading up

The Wiki article is pretty good:


First deployed on the Boeing KC-46 Air Force tanker, the MCAS software flight control law adjusts the horizontal stabilizer to push the nose down when the aircraft is operating in manual flight with flaps up at an elevated angle of attack (AoA). On the Boeing 737 MAX, MCAS was intended to mimic pitching behavior similar to aircraft in the previous generation of the series, the Boeing 737 NG. In both crashes, MCAS was activated by an erroneous indication from an AoA sensor on the exterior of the airplane.

As far as I'm aware, the 787 doesn't have an MCAS. The stab and elevators do work together much more than on previous types though. When you pull back on the yoke, the elevators will move for the first 2 seconds, then the stab will take over as the system sees it as a long term pitch input.

Just did a Google and the 787 is fly by wire, so it wouldn't have MCAS or anything like that, the handling characteristics are, like Airbus, in the software that translates pilot inputs into control surface movements.

https://www.boeing.com/commercial/787/by-design/ describes, but it's a very image-laden site that's not easy to quote!

If the 737 was fly by wire, then it'd be easy to make it feel exactly the same as a 737 Classic.
 

Bungle158

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MCAS is not "designed to keep the thing from falling out of the sky", it's intended to modify the control inputs so that a Max handles the same as a classic 737, allowing it to be flown on the same type rating*. Even were it not present at all, or disabled, it would not "fall out of the sky".

* For the unfamiliar it's a bit like signing a specific class of unit on the railway, but generally a pilot only "signs" one type of aircraft to avoid confusion, so you can understand why airlines like the idea of this.
My point is that like myself, most passengers lack the level of technical knowledge shown here. From a purely anecdotal viewpoint, there is a lot of mistrust for the Max out there. Rightly or wrongly, l share that
 

Bletchleyite

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My point is that like myself, most passengers lack the level of technical knowledge shown here. From a purely anecdotal viewpoint, there is a lot of mistrust for the Max out there. Rightly or wrongly, l share that

I certainly think there is an issue with Boeing's attitude to this whole thing, and that certainly raises concerns. On the other hand many fears held by the wider public about aspects of flying tend to stem from being misinformed - such as the idea that if the engines stop it will pancake vertically downwards immediately. Though I guess the film about the Hudson crash probably means people are better informed about that sort of thing than they were.

On the other hand, my job is business IT, which is basically never safety-critical, and even we recognise that if you can design something so it's intuitive to use, and so that you can't break it by doing something wrong, you should. This is a bit closer to the Airbus philosophy, but the idea that you'd have something that would cause a potentially fatal control input running off one sensor does just beggar belief, as well as making you wonder what else they've saved 50p on.

FWIW, there do exist aircraft with what is termed "relaxed stability", i.e. if the computer failed it would fall out of the sky because a human couldn't keep up with required control inputs. They tend to be military aircraft, though, as with those manoeuvrability takes priority over safety. I'm pretty sure the Eurofighter is one such aircraft.
 

Ted633

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A lot of aircraft have their software modified, or bodged as some would say, to refine characteristics. An example will be the 777-300. The more recent versions do not have a tail skid, as the software has been modified to stop pilots having a tail strike on take off. The same has been done with the 787-10.

Hadn't thought of the Max not being fly-by-wire, it's not something I deal with anymore now the jumbo as gone. The MCAS system would still exist if the Max was FBW, but it would just be a function of the primary flight computer that would just do its own thing in the background.

Yes, there are aircraft that would fall out the sky without the flight computer. All modern fighter jets (F-16 onwards) are like this and is the reason they are so mobile. The B-2 stealth bomber is another as flying wings aren't the easiest of things to fly unassisted!
 

TheEdge

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Bringing in thing like fighters isn't really related, military vehicles are a whole different kettle of fish. A Huey will fly full of holes and an A10 will fly when most other aircraft have disintegrated, doesn't mean the bus to Mallorca needs hollow tube control bars and a titanium armoured bathtub round the cockpit.

Fly by wire aircraft were designed from day one to have software do these jobs. 777-300 having an adaption to put in something to stop tailstrikes is an issue being discovered in service and having a fix applied. MCAS is Boeing knowing the MAX had different flying characteristics to the NG from day one, hiding that fact with software to make it an easier sell and then not telling airlines and pilots software was altering the flying characteristics.
 

JonasB

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Ah. Absolute statistics.

For comparison, how many A320neo flights were made in the same timeframe, and how many of those fell out of the sky?

(I genuinely don’t know, but reckon it’s around 2 million and none respectively)

One crash per year is pretty bad considering Boeing had delivered less than 400 Max when it was grounded. I don't know how many A320neo flights that where done, but no crashes is correct. Also Airbus has delivered over 400 A350s that have been in service since 2015, and none have crashed.

I can't find the source now, but i remember reading an article by someone who had done the maths and with that crash rate, if the 737Max had been as common as the 737NG there would be one crash per week.
 

Irascible

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MCAS is not "designed to keep the thing from falling out of the sky", it's intended to modify the control inputs so that a Max handles the same as a classic 737, allowing it to be flown on the same type rating*. Even were it not present at all, or disabled, it would not "fall out of the sky".

* For the unfamiliar it's a bit like signing a specific class of unit on the railway, but generally a pilot only "signs" one type of aircraft to avoid confusion, so you can understand why airlines like the idea of this.
That may not be 100% correct - certainly was sold as such, but then they upped the range of motion considerably without going back & redesigning which was a notable factor in the disasters. Learned opinion I've been offered has suggested there is a bit more to it than correcting the column going light. Why the hell did they use the *stabilizer* to correct *feel*, it's mindboggling that that made it through any sort of assessment.

Any half decent pilot is going to avoid accidentally stalling mid turn even if it suddenly turned off, but then half decent pilots manage to avoid fighting airbuses into the ground too...
 

scosutsut

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I think on balance I'm still where I was. The aerodynamics of the Max were compromised because the airframe was never designed to take the bigger engines but the determination to launch the product (financial) led to MCAS being provided as the solution (as it was cheaper and faster to market than a redesign) and so they could maintain a common type rating (to boost popularity with airlines and sell more.)

Add to the mix the fact they didn't educate their customers about it (instead they hid it) and they made some really bad design decisions along the way of that implementation.

So £££ or more to the point $$$ over safety. A toxic combination of greed and incompetence.

Will the Max be safe going forward. Probably yes. The gaps have been plugged and the awareness is there in the most.

Will it be forgotten about, and Boeing get away with it? Ethically it stinks to high heaven but let's face it, it appears they already have.

Will they sell more, probably post crisis, because of the common type rating aspect is largely being maintained, finance will be cheap and the only real alternative at that size A3xx neo range will have longer lead times.

To go back to the Comet example I still think it's a case that it was ruined by what happened which wasn't really fair, and in the Max situation the exact opposite is going to happen. Boeing deserve much worse.

So will I get on a Max with my family? Not if I can avoid it. But at this point that's not really going to be about safety. It's about personal principle. As pointless as that is but it's where I'm at.
 

jfollows

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So will I get on a Max with my family? Not if I can avoid it. But at this point that's not really going to be about safety. It's about personal principle. As pointless as that is but it's where I'm at.
I think you're right in your analysis and your conclusions, and that your actions aren't pointless either. I share your principles and if more people did then there would be a real effect, and even if there aren't enough people to make a difference it's still the right thing do - to stick to your principles.
 

Irascible

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The Comet failure was a problem of being first to do something - I would also imagine it was a bit costlier to work on than the 707 given the layout of it, and well, the 707 was a little more advanced even if it had a sizeable number of issues itself. The Comet did advance the science of crash investigation significantly too.

The first time I flew, it was on a DC-10 three weeks after they'd been ungrounded ( which at least is better than my friend who was *on* one when they were grounded! ). It wasn't meant to be a DC-10 - some codeshare schenanigans - on the route and more than half the passengers refused to get off the bus to board it when they saw it, but I didn't have a choice. That may have put me off MD products for life, and MD certainly has it's sticky fingers embedded into Boeing now.
 

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Whilst I've no doubt it's airworthy, it's strikes me as a terrible design. Aircraft should naturally fly straight and level without manufacturers having to program the horizontal stabilisers to permanently push the nose down to maintain a level angle of attack. In my opinion, that puts constant (excess) stress on the airframe, elevators and ailerons which over 30 years is perhaps unwise.
 
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Bletchleyite

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Whilst I've no doubt it's airworthy, it's strikes me as a terrible design. Aircraft should naturally fly straight and level without manufacturers having to program the horizontal stabilisers to permanently push the nose down to maintain a level angle of attack. In my opinion, that puts constant (excess) stress on the airframe, elevators and ailerons which over 30 years is perhaps unwise.

That's called "adjusting the trim" and you do it on all aircraft depending on the load. It's not quite what MCAS is doing. It's to make it handle the same as a regular 737 in certain cases where it otherwise wouldn't.
 

Irascible

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Whilst I've no doubt it's airworthy, it's strikes me as a terrible design. Aircraft should naturally fly straight and level without manufacturers having to program the horizontal stabilisers to permanently push the nose down to maintain a level angle of attack. In my opinion, that puts constant (excess) stress on the airframe, elevators and ailerons which over 30 years is perhaps unwise.

Centre of lift moves back and forwards depending on speed & AoA, flap deployment etc, so you have to adjust anyway - the starting point will depend on where the centre of mass is which is also not stationary, depends on load distribution, pitch, how much fuel you've used, where you pumped all the fuel ( you can do that to trim too if the tanks are placed right - Concorde had a fuel tank in the tail specifically for it ), how many passengers just walked down the back, etc etc. Even changing power on underslung engines will have the same effect given their lever arm. The reason the horizontal stab moves at all is to trim the aircraft, it's something that happens constantly whether it's automated or not. Older 737s have a thing called Speed Trim which is an auto trim system ( you might indeed wonder why MCAS is necessary when there already *was* a trim system - I do too ). Airbus FBW aircraft also auto-trim as you might expect, I think that was a factor in the Air France 330 crash ( a bigger factor was the pilot trying to take it to orbit, so you can't really blame the aircraft ). IIRC there's yet another trim system that the 737 uses in the landing regime. The whole aircraft is the hardware equivalent of spaghetti code...
 

scosutsut

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I think you're right in your analysis and your conclusions, and that your actions aren't pointless either. I share your principles and if more people did then there would be a real effect, and even if there aren't enough people to make a difference it's still the right thing do - to stick to your principles.
Just knowing I'm not the only one sitting sticking the fingers up at them is worth something :D
 

Swanny200

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It all seems to do with money and training, on the money side of it, Boeing just want to eke as much money out of an outdated platform by as others here have said bodging it to within an inch of it's life, moving the CoG has long been said to have been what started the problems in the first place.

In terms of training, I point you to the Air France 296 Airbus crash at Habsheim, yes there was other factors, but Airbus denied for years that there was any issues with the engine or any delay in thrust, if you believe a lot of the legal team on behalf of the very experienced pilot, Airbus even went as far as to collude with the French authorities to switch black boxes as they had buyers queuing up for the A320 and anything other than pilot error would have eradicated those orders, the pilot still to this day claims that even though the alpha protection protocol had activated to prevent the plane from stall, as soon as full power was asked for, he should have got it, he states he had to throttle back and ask for it a 2nd time before it responded and by that time it was too late.

Airbus/Air France hadn't trained the pilot correctly and told him of a lot of the features of the new plane, the A320 has simply thought that at that height and speed, that the pilot was landing so ignored the instruction for go around power, the pilot didn't even know this "safety" feature existed, he was the senior pilot for Air France and yet nobody told him of these features.

The 737 Max is another incident where "safety" systems are fitted to a plane and the pilots who fly them and to a certain extent the carriers that use them, were not given detail about them or told how to deal with them in certain incidences.
 

Irascible

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The MAX training *wasn't allowed* to include anything about MCAS, or the aircraft would have needed recertifying! never mind there was a problem whereby the trained reponse to a trim issue would reset faulty MCAS to repeat its error & leaving it alone would have stopped it fighting the pilot.

The airbus flight was way under it's altitude floor, off flightplan, high alpha & low energy, I'm not convinced any jet airliner other than a STOL craft would have got out of there, honestly.
 

TheEdge

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With all this out in the open is the MAX now its own type rating or has Boeing got away scot free on that matter?
 

Altrincham

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One the 737 Max that’s been grounded at Manchester for almost 2 years (G-TUMB) is currently doing some sort of test flight
 

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Irascible

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With all this out in the open is the MAX now its own type rating or has Boeing got away scot free on that matter?

I don't know about a new type rating, but they're not getting away with minimal training anymore that's for sure.
 

b0b

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With all this out in the open is the MAX now its own type rating or has Boeing got away scot free on that matter?
same type rating, but mandatory simulator training now required on max differences. That will invoke a penalty on Boeing from Southwest

Not been on one yet. Cant wait to try it.
shockingly quiet over the NG, its impressive to me. but I haven't flown anything other than 737's in a long time now
 
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