Ethiopian 737-8 MAX down. No survivors.

Thanks... I forgot about the ventral fin on some 707s...

A friend (corporate pilot) told me that the large TWIN ventral fins (strakes?) on the Learjet are for yaw control, but they also provide a nose-down moment at high AOA. Seems like that might help if true.

 

That wasn't an empty slogan with Blue. It was applied many times.

 

The Lear ventral fins on the models after the 35 also (helped) fixed the deep stall issue with the T tail at high AOA. The 35 has a stick pusher to help you stay out of the deep stall, and then the 45 and later got rid of the pusher with the fins and just have a stick shaker.

 

Thanks, didn't know all of that...since I never flew those little tin jets. Never flew the big tin jets either.

 

The automation is not how most people imagine it. It needs constant monitoring during anything other than cruise flight. We also tell it exactly what to do and when. It’s not “smart.”

 

The big reason people put them on the 35 is it allows you to fly with one (of two) yaw dampers inop. I think it's also tied with a gross weight increase STC, but I'm not sure.

 

One of the primary things that will come out of this debacle is Boeing will stop selling planes to airlines who get their pilots from Sesame Street.

 

Or Airlines might cancel orders .Lion Air have 200 on order and not happy they way Boeing handled the last crash ....-$20 billion would make a dent in Boeing profits.

 

Not likely. Also Boeing sells a large number of airplanes to lessors, so Boeing does not have control over where those airplanes ultimately end up in service. More likely, in cases such as China, Boeing will promise more work off-load for parts and assemblies. No different than Airbus or any other commercial airplane manufacturer.

 

A solution of course that is wholly unrelated to the issue at hand.......but I suppose if we can't fix that we can at least appear to be doing something.......

 

According to the french BEA, the Cockpit Voice Recorder's data is intact, has been downloaded and sent to ethiopian authorities for analysis. No comment from the BEA about the content.

Rgds

 

I think one fact that will find general agreement is that there's no excuse for all of the geo-political screwing around and delay with the FDR and CVR.

 

The BEA has just confirmed that data from the CVR was intact, has been downloaded by them and sent to the enquirers, but not listened to by the BEA itself.
The FDR could be a much more difficult challenge, as the "box" itself is well damaged, so opening it is a tricky challenge.
Rgds

 

Comment on Al Jim's comment which was: "For the max, to fit the engine they had to move the engine further foward on the wing to mount it higher on the wing to get ground clearance (they even extended the nose gear to try to get more ground clearance). The resulting placement of the engines make the nose pitch up as power is applied, now all airplanes with engines mounted below the wings do this but the pitch up on the max is worse that other airplanes. In fact it is so bad that Boeing threw another bandaid on the max. This is the system that automatically trims the aircraft nose down under certain flight conditions to help counter the large pitch up problem. Realistically as the mission requirements for the 737 expanded Boeing should have designed a new airplane to meet these requirements but for various reasons this has not happened and therefore we have the max.

So I am not a pilot please help me understand. Is the 737 Max, with the engines more forward than before, inherently unbalanced? If you are on manual and you let go of the stick in Cruise, does it fly level? Or is it as I read somewhere that once they moved the engines forward, they had to design in software to make up for the balance problem, with the result that, when you go to manual now, the computer overr-dies you, the pilot, and says "No, we have to dive to get more lift under the wings?" If that's the case, they might as well cancel all the orders waiting on the assembly line because the basic design is flawed. I want to write an article predicting the same thing will happen with Level 5 autonomous cars (those without steering wheel or brake pedal) , but am still not sure if with the 737 Max we are talking about an inherently bad design overall, or a software problem that can be fixed. I also think this 737 Max will lead to one of the biggest lawsuits in history, if they can find company ,memos internally that show company officials knew about the flaw but decided not to tell the pilots or public.

 

Before the law suit, don't you think we ought to know why it crashed?

The other one had a known issue that should have grounded the airplane. We are all guessing on this one.

 

If it is trimmed in Cruise even the Max should fly straight and level. The problem appears to come from two things: 1) a faulty angle of attack sensor 2) an unbalanced design which mandates control software. The first one is an easy problem to solve. The second one is at the intersection of the system no longer augmenting the pilot but overriding their actions.

One aircraft that can not fly without control software is the B2 bomber. With no vertical stablizer, control software manages the airplane in flight. It is unlikely a pilot could fly that aircraft without the computer managing the flight surfaces. It is an unstable aircraft.

So it is alleged Boeing has built another somewhat unstable aircraft known as the 737 MAX which without control software will pitch up as power is applied. The control software tries to force the nose down and is basically fighting the pilot for control of the plane. I don't know how bad the pitch up problem practically is but what is clear is that the applied solution is far worse than the problem. Any decent pilot can manage a pitch up if they expect it when they advance the throttles.

I'm sure the FDR will show exactly what happened.

 

The system that is supposed to reduce pitch up characteristics is SPEED TRIM...... all NGs and MAX have it.

The system that moves the elevator to reduce pitch “MCAS”.... ONLY works during speeds approaching stall and STEEP Turns under high loading.

MCAS has nothing to do with pitching moments caused by thrust.

 

OK I wrote this editorial to compare this with the fast coming autonomous cars. I have never flown a plane but been in a few experimental cars (one I crashed and coincidentally it had no steering wheel...) Any opinions?
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Boeing Crashes:How it applies Anonymous cars

When the Boeing 737 Max came out in 2017, it looked good. Better fuel efficiency. Higher off the ground when parked (the old version was too low). Airlines ordered them like crazy.

Then came the crashes. It was only after the second one, in Ethiopia, that it became clear that there was a pattern. The NYT published an article that showed the wild porpoise-like motions that both aircraft recorded, almost too much for a pilot to get ahead of even if he went to full manual.

Now it’s coming out—that they told pilots that were 737-qualified that, don’t worry this is just an updated version of the plane you already know. That way they didn’t have to school them all over again.

But even as crash results from the second cash are being analyzed, it is becoming aware that the plane had a severe problem, the software would sense that it was going too slow so it would pitch the nose downward. When the pilot tried to bring it back up, it would fight the pilot and insist on diving again. Finally, after so many roller-coaster maneuvers, the pilot couldn’t keep up. And the plane went down. This is borne out by the NYT article that shows the altitude changes each plane went through, a frantic pitching up and down like a roller coaster.

I think, and this will no doubt come up in Congressional hearings or court, that, when they moved the engines forward of the original design, in order to have the plane sit taller while on the ground, they changed the handling of the plane. They thought they fixed this by designing software so it would “feel” like the previous version. So a pilot that flew the old version would feel comfortable. But they didn’t want to alarm the pilots and tell them it was an all new plane that they would have to qualify for all over again. So some that flew it weren’t told of the software’s ability to negate their attempts at saving the plane. A pilot who tried to "save" it the old way was over-ruled by Hal, the robot.

Who is the culprit? The software designers who didn’t warn the public? The directors of Boeing who didn’t want to develop a brand new plane but kept making updates on a design that couldn’t take all the updates? All that will be decided in court down the road, but meanwhile those 135-plus 737 Max planes that were grounded may remain parked, and thousands of orders will be cancelled. It is a black eye for American industry.

WILL THIS SAME SCENERIO HAPPEN WITH AUTONOMOUS CARS?

Electric cars are being pushed down our throat by environmentalists, some of whom are already talking about killing off all new cars with internal combustion engines by 2030. Coincident with that is the push for autonomous cars. We are at Level 2 now with some 2019 cars equipped with software that warns of traffic on the side, allows you to drive in rush hour traffic letting the car do all the starting and stopping, etc.

But the real goal of the automakers and the ecologists is Level 5, where we no longer have brake pedals and a steering wheel. Oh, there might still be a person sitting where the steering wheel used to be but if the software fouls up in a level 5, there’s no way the human former driver can ”save” the situation. There’s already been a couple pedestrians killed by autonomous cars, and those were experimental cars with a human “safety” driver that was expected to grab the controls and resume human piloting in an emergency. They failed.

And yet more and more States, eager to have money spent in their State on testing of autonomous car fleets, are authorizing experimental prototype autonomous cars to test in their state in regular traffic, with ordinary drivers of regular cars around them not aware that these prototypes are being guided solely by software.

I am predicting the Boeing problem, where in court we will find out that the automaker was in such a hurry to get Level 5 autonomous cars on the market that they disregarded safety “warnings” from insiders. Only instead of a major US aircraft manufacturer going down in a hail of litigation, (Boeing could go broke if the evidence comes out against them, as not pilot error) it will be a major automaker who juries, looking at internal e-mail, will find disregarded internal warnings that they were putting a flawed system out on the market.

What am I asking for? Just more testing with robots. Yes, pedestrians, dogs, all robotized, walking around a simulated neighborhood (like a movie set neighborhood) mixed in with real drivers in regular cars, test drivers with all the safety equipment NASCAR has on the shelves . Keep testing until each new design can go 100,000 miles plus without an accident. Or, hell, a million miles, whatever it takes.

In the short term, Boeing will come out with a software patch that just about appears to be the solution. But if it turns out their design is fundamentally flawed, that their decision to move the engines forward unbalanced the plane and the software fix they devised to simulate the handling of the previous version didn’t work, they will have to start over with an all new design, which could take years. And they will have to scrap the 1,200 to 4,000 planes on the assembly line (I heard two numbers) . That’s better for public safety than say, losing one airliner full of passengers a year (this time it was two within a few months).

I am a fan of internal combustion engines in cars. I can give those up for electrics if I have to . But giving up the ability for a driver to “manually” take over a misguided autonomous car is too much to ask for now that we have the Boeing example. Boeing tried to save money by using software to make up for a bad re-design of what had been a reliable plane. And 346 passengers died because of it.

 

^^^Sorry, but it is the same 737 as the NG with new engines and a few minor cockpit display updates. I don’t hear anyone talking about the new Airbus 320 Neo...it’s got new, larger diameter engines as well. The biggest issues we have flying the Max vs the NG....longer engine start times and cool down times. That’s it....nothing to see here folks. Wait for the investigations to wrap up.

 

I am a pilot (and flight instructor), but not a 737 pilot, so take this with a big grain of salt...

The MCAS system happens because in certain situations, situations where the typical pilot is unlikely to be flying, the pitch forces to raise the nose are too light. In normal parts of the performance envelope, the airplane flies just fine. Even in those corners where this is an issue, the airplane flies okay but it doesn't meet the certification criteria for yoke forces.

So, to fix this, Boeing added a system which trimmed the nose down automatically in those certain situations. And when this is working, it's all fine and completely behind the scenes.

However, as with any automated system, when it receives bad data (garbage in, garbage out), it reacts incorrectly. In this particular case, amazingly (to me), they relied on only a single data source, so if that data source should go bad, the system is going to react badly. The fix for this is going to be three things: 1) rely on two data sources; 2) improve procedures and training for this scenario, and 3) figure out why the data source is failing and fix that.

How does this apply to autonomous cars? I don't know... maybe that cars (and airplanes) are designed by humans and will have human errors embedded in their design regardless of how carefully they are thought through?

I do think you need to be careful in drawing conclusions here. Will there be some autonomous car accidents? Sure, already have been. But there are lots and lots of manually controlled cars which crash and kill people, too! Are you comparing autonomous cars to a "perfect" world which doesn't exist, and will never exist?

 

MCAS only works during manual flight. That is not a situation where the typical pilot is unlikely to be flying.

 

Thanks for the correction. If I understand the problem both crashes appear to have been caused because the MCAS system thought the plane was stalling from an angle of attack sensor and forced a nose down.

 

Why does MCAS only function when in manual flight and not autopilot? Isn't the purpose of it due to engine positioning and needing it to maintain safe AOA to prevent stall? Engine position doesn't change between autopilot and manual flight so I don't understand why it is only on in manual.

 

I’m thinking it’s because the autopilot isn’t going to let the airplane go below min speed.

 

That is not the definition of an unstable aircraft. Pitch will change in any aircraft when undergoing configuration (e.g. extending/retracting flap or landing gear) or power changes.

The 737MAX is not an unstable aircraft that requires software to maintain a static flight condition. I am not aware of any commercial or general aviation aircraft that is inherently unstable, and AFAIK the regs do not even allow it.