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BANGKOK 25 May 2019 16:43
webfact

Boeing reshuffles top engineers amid 737 MAX crisis

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Posted (edited)
16 minutes ago, jpinx said:

Giving an automatic system authority over flight controls, based on the input of a single sensor is nothing short of criminal!

It’ll be for the lawyers to fight that out, but the applicable functional safety standards are going to give the prosecution a great deal of ammunition in that fight.

 

Your point regarding a single sensor for such critical service is bang on. 

 

 

 

Edited by Chomper Higgot
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Posted (edited)
25 minutes ago, jpinx said:

Giving an automatic system authority over flight controls, based on the input of a single sensor is nothing short of criminal!

 

There's an interesting article from the NYT that just went live on how two of the features that might have prevented these kinds of crashes were sold as extra cost options on the 737 Max by Boeing instead of being included in the core plane design/product, and neither of the crashed airlines had paid extra for them, thus their planes didn't have them.

 

https://www.nytimes.com/2019/03/21/business/boeing-safety-features-charge.html

 

Quote

 

Boeing’s optional safety features, in part, could have helped the pilots detect any erroneous readings. One of the optional upgrades, the angle of attack indicator, displays the readings of the two sensors. The other, called a disagree light, is activated if those sensors are at odds with one another.
 

Boeing will soon update the MCAS software, and will also make the disagree light standard on all new 737 Max planes, according to a person familiar with the changes, who spoke on condition of anonymity because they have not been made public. The angle of attack indicator will remain an option that airlines can buy. Neither feature was mandated by the Federal Aviation Administration.

 

 

 

Edited by TallGuyJohninBKK
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On 3/20/2019 at 10:15 AM, lannarebirth said:

The NTSB is the gold standard of investigative agencies. Their report will pull no punches and be both believed and acted upon by everyone.

Yes, they may investigate. So did they give a gold standard to the Malaysian Boeing airline crashes?

Still unresolved due to political pressure I believe.

 But the issue is about FAA. And why they allowed a computer programme to override the pilot without further testing.

And why they allowed the instructions to pilots but never ensured that the instructions were ever taught to overseas pilots.

The first crash allowed them and Boeing ample time to correct the issue. They did nothing. They will both be condemned and rightly so.

I have no doubt that Boeing will fix this issue. But why did they not fix it after the first crash.

And I am sure some massive legal bills and compensation will result.

Sell Boeing now, buy back after it plummets is my callous economic washing of the hands.

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Yes, was only a matter of time till that happened, followed by other countries don't trusting the FAA on this anymore. Hence the action from other countries before the USA, and hence "Europe and Canada said they would seek their own guarantees over the safety of Boeing's 737 MAX'.
It seems obvious the FAA can not be trusted on this anymore.
Yes it seems they (Boeing)were basically allowed to self certify parts of the process with too little oversight. Think there will be some back-peddling on this procedure.

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One wonders why the need for a 'gizzmo' to right the aircraft at the stall and beyond.= and no means of overriding the system, that is if the system had an override ! Airliners have managed without this 'gizzmo' for many many years. Two highly trained and highly paid pilots up front can monitor speed and angle of climb and take steps to correct as necessary . Audible and 'control column  shake' warnings have been fitted to many aircraft for years in case the pilots were distracted. Keep it simple Boeing .
 
The difference with this model is the size and position of the larger engine tending to push the nose up (making the aircraft less stable?). This is why they needed additional system.
MAYBE this is a problem revamping an existing design, rather than starting from scratch.

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On March 20, 2019 at 3:14 AM, Ulic said:

 

Agree 100%. The FAA is far too close to Boeing and business. Just bootlickers for Boeing. The NTSB is the investigative gold standard and pulls no punches. Manufactures, pilots, airline maintenance and pilot training will all be put under the microscope and a clear picture will emerge as to exactly what happened, all in an effort to correct deficiencies and make the industry safer.

You mean the NTSB whose board members get appointed by Trump, 555. I'll be sticking to Airbus while the Trump Regime is in place. This may be his "atta boy Brownie" moment.

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On 3/21/2019 at 10:19 PM, jpinx said:

I think the reference is to the aircraft having a limited range of CofG which is further limited in the configuration/flight condition of a stall. Aircraft are usually designed to stall the main wing first. Stalling the tailplane is a "deep stall" and has different characteristics.  Stalling the tailplane before the mainwing is not something I've tried, but I'd expect a severe tail-down movement as the tailplane loses lift. You'd need to ask a Pitts jockey to try it for you. 😉

 

Boeing, Airbus, et al are always pushing the boundaries of aerodynamics - sometimes with spectacularly impressive results, but the underlying rules of the science are the same and must be respected.

great answer and I had never thought of that as the way you explained it, I was thinking at the time about the aircraft flying/going backwards into the ground because as I understand it it's almost impossible for an airliner to recover from a stall like that. I have seen many aerobatic videos of aircraft falling through smoke vertically with the nose straight up  and that's where I was coming from with my comment.

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On 3/21/2019 at 10:19 AM, jpinx said:

Aircraft are usually designed to stall the main wing first. Stalling the tailplane is a "deep stall" and has different characteristics.  Stalling the tailplane before the mainwing is not something I've tried, but I'd expect a severe tail-down movement as the tailplane loses lift. You'd need to ask a Pitts jockey to try it for you. 😉

 

Boeing, Airbus, et al are always pushing the boundaries of aerodynamics - sometimes with spectacularly impressive results, but the underlying rules of the science are the same and must be respected.

 

I'm wondering when they're going to eliminate the tailplane (and inherent parasitic drag) altogether, in favor of front end canards.  The biggest problem I see with a tailplane is that the lift it generates pulls the tail down, and has to be counteracted by more lift from the wing.  All of that creates drag. 

 

A front end canard lifts the front end, adding to overall lift and taking some load from the wing.  Seems like that's a way to get more km per ton of fuel.

 

But, I'm not an aerospace guy.  I'd be interested to hear from someone who is.

 

 

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On 3/27/2019 at 4:19 PM, impulse said:

 

I'm wondering when they're going to eliminate the tailplane (and inherent parasitic drag) altogether, in favor of front end canards.  The biggest problem I see with a tailplane is that the lift it generates pulls the tail down, and has to be counteracted by more lift from the wing.  All of that creates drag. 

 

A front end canard lifts the front end, adding to overall lift and taking some load from the wing.  Seems like that's a way to get more km per ton of fuel.

 

But, I'm not an aerospace guy.  I'd be interested to hear from someone who is.

 

 

Several fighter jets are "canard" configurations.   Search for Saab Viggen, and the currently in-service UK's Typhoon. It's front end control makes it enormously capable, much more than a tailplane could manage. Imagine something like the Typhoon scaled up to the double-decker airbus size -- it'd be a most impressive monster !

 

The conventional tailplane is used to alter the main wings angle of attack, which controls the lift generated.  The heavier the aircraft, the more lift is needed, so the angle of attack needs to be greater. The tailplane pushes the tail down to change the attitude and increase the angle of attack. It's counter intuitive, pushing down when you need more lift, and that is the dilemna. Look back at early pioneers, building and flying their own "string-kites" and you'll probably notice that there were a fair number of designs with the small wing at the front. The need for a small wing is simply because balancing the whole weight of the machine on one wing restricts the possible position of the centre of gravity. I reckon the little wing moved to the back to get it out of the pilot's field of view, and there it has stayed ever since -- a bit like first gear in manual car gearboxes is to the left and forwards --  unless you're French! 😉

 

Aircraft companies have to keep costs down, and to totally re-think the most basic configuration would be to re-start the aerospace industry, and it's certification, and no-one has pockets that deep, but it's a very nice thought to play with .🙂

 

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1 hour ago, jpinx said:

Aircraft companies have to keep costs down, and to totally re-think the most basic configuration would be to re-start the aerospace industry, and it's certification, and no-one has pockets that deep, but it's a very nice thought to play with .

 

I'm afraid that what's missing here is that, in order to keep commonality of parts while using the new engine, Boeing was required to create a fundamentally unstable aircraft that relies on a computer to keep it in the air.  That flies in the face of 70+ years of convention that commercial aircraft (as opposed to military aircraft) need to be inherently stable even if the power goes dead.

 

Even if they revamp the software, they still end up with an inherently unstable aircraft.  And I believe that's why they quietly tried to sneak the MCAS system in without adequate pilot training- to keep from revealing the plane violates a pretty sacred convention.  That it be inherently stable.

 

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Posted (edited)
On 3/30/2019 at 11:51 AM, impulse said:

 

I'm afraid that what's missing here is that, in order to keep commonality of parts while using the new engine, Boeing was required to create a fundamentally unstable aircraft that relies on a computer to keep it in the air.  That flies in the face of 70+ years of convention that commercial aircraft (as opposed to military aircraft) need to be inherently stable even if the power goes dead.

 

Even if they revamp the software, they still end up with an inherently unstable aircraft.  And I believe that's why they quietly tried to sneak the MCAS system in without adequate pilot training- to keep from revealing the plane violates a pretty sacred convention.  That it be inherently stable.

 

Grandfathering certification is the root cause.  If that was not allowed *every* aircraft would need it's own certification, whether it's a Mk I or Mk II , but that's a more fundamental change to certification than the industry could support.

Edited by jpinx

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