Ethiopia crash

[threexgreen 3,139]

14 hours ago, Bobsk8 said:

Interesting reading. https://www.vox.com/business-and-finance/2019/3/29/18281270/737-max-faa-scandal-explained

What I find questionable about this article is its stance on the aircraft itself and the fact that it exists. It seems to suggest like quite a number of other sources that the 737 MAX is an aircraft that makes no sense and shouldn't exist. 5000 orders and the pace at which the order book filled speak for quite the opposite. Boeing made the decision to go for the MAX instead of a whole new concept based on what was/is best from a business point of view: being able to keep up with the A320neo. I see no problem with that (I do, though, with the speedy process of it all and the fishy certification procedure). In order to do that, the engines had to be mounted differently to fit which caused the flight characteristics to change in a way that admittedly is not adequate. However, with the introduction of MCAS that problem was solved and it didn't even need much effort. The point where it went wrong is the initial design of MCAS (plus Boeing not telling about it) which should have been designed like it is now with the fix. This, in my opinion, however, is not even remotely enough to suggest the whole plane as a decision and concept is a mishap.

Edited March 30, 2019 by threegreen

[Reader 2,021]

Hello again.

As a completely uninformed observation, in the modern parlance, there is a "duty of care" upon the aircraft designers to the subsequent users of that aircraft.

We are no longer in the early days of aviation when there was a substantial and accepted risk of mechanical and/or pilot failure.

The way in which an apparent inherent instability was introduced to a previously stable design and then concealed by a "fix" which was not properly thought through and not properly notified to those who would fly it suggests to this uninformed person that this duty of care was over-ridden by business concerns.

While this kind of practice seems widespread where there are sums of money involved, this does not make it acceptable.

Edited March 30, 2019 by Reader

[threexgreen 3,139]

6 hours ago, Reader said:

The way in which an apparent inherent instability was introduced to a previously stable design and then concealed by a "fix"

Your statement here seems to imply the aircraft is an unstable design, which it is not at all. The behaviour in a certain flight situation (close to stall) is different because of the different engine position and size. This in itself doesn't make the aircraft unstable (or unbalanced, as many others on different sites like to point out). FAA certification requires the pilot to be able to pull the control column all the way back when inducing a stall. At a certain AoA, the MAX will start to increase the rate at which the nose rises due to the engines, so the pilot will have to release back pressure to keep a steady rate. Because this doesn't meet the certification requirements, MCAS is used to counteract the increased nose up momentum so the pilot can keep pulling until fully backward. Feel free to disagree, but since the whole mess with the MAX started, I still cannot see how this makes the aircraft unstable (or unbalanced). An actual unstable aircraft won't be certified, even if the FAA is on the manufacturer's side. Like I said in my previous post, the issue is that MCAS was, like you say, not properly thought through. The issue is not an unstable aircraft.

Boeing didn't think it was necessary to tell pilots about it and did screw up royally by making that decision but they are not trying to conceal anything.

[Christopher Low 5,354]

Quote

The issue is not an unstable aircraft.

The issue appears to be unstable management at both Boeing and the FAA. Quite how self certification can ever be considered to be a sensible option in the aviation industry is totally beyond my ability to understand.

Edited March 30, 2019 by Christopher Low

[59Line 2]

On 3/28/2019 at 6:53 PM, Jim Young said:

I did find a small fault in your conversation though

I'm compelled to agree.  I can see how I presented that poorly.  If I may, try to clairify.  From a legal liability perspective, the jury is still out with me.  The details and circumstance behind the large and catastrophic loss of life involve to many people and circumstances for me to even venture a "best guess".  Like not purchasing 2 safety features offered, that will definitely come up.  Boeing's fault? No. It has been very strange to me that so much focus is on Boeing, when the legal process starts with the airlines involved and may or may not roll Boeing into it.  The question is if the product was used correctly, before the question of deffective product. Usually. I personally find it highly unlikely that Boeing or the airlines would deliberately and purposly put lives at risk. Bodycounts are extremely bad for business.  An example that comes to mind would be the seaplanes that opperated from Miami to the islands. I can't remember the name. But 1 crash near the Port of Miami and they were out of business. Neglegance by the airline and/or Boeing is likely as it is a much lower burden of proof.  But again.  I'll have to wait for the investigation, attorney's and courts to dispose of that information before it becomes concrete public information. Legal processes are lengthy ones.  Large ones hostorically take years to settle.

From a fleet management position, personally (just my opinion) I would be furious with Boeing.  The reps know their clients extremely well and what their needs are or likely to be given any direction the client may go.  In most cases equipment inventory is kept to a minium.  As anything not in use is costing money not earning it. Generally speaking. In my experience this tends to be less of a problem for large fleets than it is for smaller ones.  Basically a percentage game. Before it becomes critical and starts to affect the business's ability to handle the work load efficiently and remain profitable.  Tooting's article link highlights it very well.  15%. ouch!!   At that critical point is where I have seen numerous transportation business take a "do the best you can with what you have" stance and pray nothing goes wrong until things get better.  I try to watch for companies leaning that direction and avoid them. Not only for cargo liability but self preservation as well. Probably less of a problem with airlines than ground transport, (I hope) but human nature non the less.   

The longer the grounding continues, the worse it will get for Boeing. (Again my opinion) I'm sure they are more than aware of it and I would not be surprised to start seeing the Max in the air again soon. 

Confidence, owners/pilots&public is a different and very real problem and difficult to gauge as things play out. Something I am trying to ferret out myself.  Hopefully it works out.  Where I am at, the arrival of one variant of the 737 or another is as much routine as the sun coming up in the morning. For as long as anyone can remember.  Five or six decades, and maybe going to 7 or 8? We can't help but love the old crow!

Most of this has been presented, I know.

My thanks to goates for the link I was wondering about.

Wait, the seaplane example was Chalks -Thank you google.

 

 

[John_Cillis 2,406]

6 minutes ago, Christopher Low said:

The issue appears to be unstable management at both Boeing and the FAA. Quite how self certification can ever be considered to be a sensible option in the aviation industry is totally beyond my ability to understand.

Yes,

There is always a rush to get a new or changed design out the door, although one thing I have learned as software QA I will share here.  It is quite often that post release issues do not show up after QA and User Acceptance testing because QA simply knows more than the customer (in this case the airline pilot) knows about the product, thus if there are issues QA simply has faster reflexes than those receiving the product.  Sadly the customer is often the real QA, flying in real world situations that the product development life cycle just does not anticipate.  This same type of issue could have happened with Airbus, or Embraer, and in fact has since few aircraft types have been without accidents, especially early in their lives.  Look at the Gimli glider as one example. 

I think the L1011 and 777 have been among the safest aircraft so far but in cycles, the 737 has far exceeded those aircraft and thus has had far greater risk of an accident, and the A32x series is not far behind.  GA aircraft have also had their share of accidents, and Light Sport, which I flew under, had a very high accident rate compared to other aviation flight categories. 

As long as aircraft are created by humans and flown by humans, which will be forever, human error will creep in although humans as a species are getting more intelligent and more intuitive over time, therefore reducing accidents in the future.  Thus I still have faith in Boeing and all aircraft mfrs and I do not see the end for them, and there will be new aircraft mfrs in the mix too.  Aviation will grow as most people prefer to get to their destination quickly, rail will be somewhat behind, especially in the car centric US.

John

[threexgreen 3,139]

19 minutes ago, Christopher Low said:

The issue appears to be unstable management at both Boeing and the FAA. Quite how self certification can ever be considered to be a sensible option in the aviation industry is totally beyond my ability to understand.

Fully agree.

[cowpatz 243]

34 minutes ago, threegreen said:

Your statement here seems to imply the aircraft is an unstable design, which it is not at all. The behaviour in a certain flight situation (close to stall) is different because of the different engine position and size. This in itself doesn't make the aircraft unstable (or unbalanced, as many others on different sites like to point out).

Whilst I agree to a point with that statement the other issue here is that when loaded in a turn the turn tightens and increases the load factor which further tightens the turn.....By all accounts this requires considerable forward column to correct, whereas in other airliners simply relaxing the column will correct the situation. These can all be overcome with software of course but the level of redundancy and failure analysis needs to be appropriate. As has been shown this is not the case.

[cowpatz 243]

The following article was too lengthy to post but is a great read.

https://www.dropbox.com/sh/a6zoo2eehlc07dd/AAD1EWgfmCNP9kZernzOI2Sga?dl=0

[threexgreen 3,139]

24 minutes ago, cowpatz said:

Whilst I agree to a point with that statement the other issue here is that when loaded in a turn the turn tightens and increases the load factor which further tightens the turn.....By all accounts this requires considerable forward column to correct, whereas in other airliners simply relaxing the column will correct the situation. These can all be overcome with software of course but the level of redundancy and failure analysis needs to be appropriate. As has been shown this is not the case.

That's my point: The plane behaves differently in certain situations which doesn't mean it's an unstable design. With software this is counteracted and it's not much of a topic. When the software is not designed appropriately and the crew isn't able to cope with it, however...

Edited March 30, 2019 by threegreen

[KevinAu 441]

1 hour ago, threegreen said:

 Because this doesn't meet the certification requirements, MCAS is used to counteract the increased nose up momentum so the pilot can keep pulling until fully backward.

Ok, read what you wrote one more time. This is exactly the kind of non sensical reasoning that make it so dangerous for planes to be designed solely by engineers. Mcas was not designed for pilots to stall the plane the way they expect to stall a plane. It’s meant to keep pilots from stalling the plane. It’s a stick pusher, nothing more, nothing less. As such, when the engineers lost sight of that fact, that’s when the problems started. A stick pusher masquerading as a flight control logic in order to avoid a training requirement. When the engineers forgot that the mcas was really a stick pusher, that’s when they forgot the need for dual sensor inputs, fault comparison, and inhibiting logics. Which are standard for stick pushers, because they can potentially push you into the ground.

[threexgreen 3,139]

1 hour ago, KevinAu said:

Ok, read what you wrote one more time. This is exactly the kind of non sensical reasoning that make it so dangerous for planes to be designed solely by engineers. Mcas was not designed for pilots to stall the plane the way they expect to stall a plane. It’s meant to keep pilots from stalling the plane. It’s a stick pusher, nothing more, nothing less. As such, when the engineers lost sight of that fact, that’s when the problems started. A stick pusher masquerading as a flight control logic in order to avoid a training requirement. When the engineers forgot that the mcas was really a stick pusher, that’s when they forgot the need for dual sensor inputs, fault comparison, and inhibiting logics. Which are standard for stick pushers, because they can potentially push you into the ground.

Perhaps my post wasn't as clear as it was to me, but I didn't say MCAS is to make the plane stall in a familiar way (although, when you think about it, it serves that purpose, too). MCAS provides stall prevention by pushing the nose down via stab trim input to reduce the AoA when in critical attitude. The need for MCAS on the MAX is its tendency to pitch up faster at high AoAs due to the engines which would obviously increase the danger of actually stalling. So, without MCAS, the plane would exhibit a kind of behaviour that does not conform with FAA requirements (increasing AoA at a constant rate while the is pilot pulling back steadily until fully backward when the stall occurs). Unless I'm missing something, I'm not sure what's nonsensical here.

Edit: Reading the particular sentence you quoted, the wording I used isn't so fortunate.

Edited March 30, 2019 by threegreen

[KevinAu 441]

2 hours ago, threegreen said:

Perhaps my post wasn't as clear as it was to me, but I didn't say MCAS is to make the plane stall in a familiar way (although, when you think about it, it serves that purpose, too). MCAS provides stall prevention by pushing the nose down via stab trim input to reduce the AoA when in critical attitude. The need for MCAS on the MAX is its tendency to pitch up faster at high AoAs due to the engines which would obviously increase the danger of actually stalling. So, without MCAS, the plane would exhibit a kind of behaviour that does not conform with FAA requirements (increasing AoA at a constant rate while the is pilot pulling back steadily until fully backward when the stall occurs). Unless I'm missing something, I'm not sure what's nonsensical here.

Edit: Reading the particular sentence you quoted, the wording I used isn't so fortunate.

Where I think you’re off base, is that you’re describing mcas as some kind of flight handling quality correction. And in fairness, it’s probably what Boeing’s engineers fell into thinking of it as too.  But it’s not. It’s really a stick pusher. There is no handling quality to a stick pusher. It is blunt force trauma. It yanks the control column completely out of your hands. Mcas is just a pusher that uses nose down trim and doesn’t yank the stick out of your hands. But when it kept running unchecked, it ran the trim full nose down on those guys. They were dead. There is no way you can fight that with the yoke. The mindset of this mcas as a correction for some newly induced pitch divergence at high alpha is the wrong kind of mindset that made them think it was ok to rate it acceptable for single point failure. If they surrendered themselves to the notion that this was a stick pusher, they would have treated it with the proper kind of failure analysis and consideration. They added it in lieu of a real stick pusher in order to avoid adding a training requirement for pilots and convinced themselves that it wasn’t a stick pusher. They installed a stick pusher without telling anybody. That’s why those two planes crashed.

Edited March 31, 2019 by KevinAu

[n4gix 4,947]

5 hours ago, Christopher Low said:

The issue appears to be unstable management at both Boeing and the FAA. Quite how self certification can ever be considered to be a sensible option in the aviation industry is totally beyond my ability to understand.

I read a statement from the FAA earlier (which I now cannot find again) where they stated that they have to work with manufacturers to do a lot of self-certification because of budget cutbacks that have eliminated around 10,000 inspectors!

[DrumsArt 270]

1 hour ago, n4gix said:

I read a statement from the FAA earlier (which I now cannot find again) where they stated that they have to work with manufacturers to do a lot of self-certification because of budget cutbacks that have eliminated around 10,000 inspectors!

...liberalism should sometimes be a little less liberal when it concerns security...just saying.

Edited March 31, 2019 by DrumsArt