Boeing grounds all 737 Max planes, the type involved in the Lion Air and Ethiopian crashes
It’s official; the Boeing 737 Max has been temporarily grounded everywhere:
The US plane-maker said it would suspend all 371 of the aircraft.
The Federal Aviation Administration said fresh evidence as well as newly refined satellite data prompted the decision to temporarily ban the jets…
The FAA has a team investigating the disaster at the Ethiopian Airlines crash site working with the National Transportation Safety Board.
Dan Elwell, acting administrator at the FAA, said on Wednesday: “It became clear to all parties that the track of the Ethiopian Airlines [flight] was very close and behaved very similarly to the Lion Air flight.”
He added that “the evidence we found on the ground made it even more likely the flight path was very close to Lion Air’s”.
It’s not an admission that the aircraft design is at fault. But it’s an admission that there’s reason to believe it might be.
More information here:
One of Boeing’s internal guidelines for [updating the 737 design] was that any changes must be achievable without the need for any pilot retraining. But the engines Boeing wanted to use were larger than the old versions and had to be mounted higher and farther forward on the wings. These larger engines could cause the aircraft to destabilize under certain conditions, including high-banked turns at low speed.
To counter this, Boeing developed MCAS (Maneuvering Characteristics Augmentation System). MCAS is an additional software package intended to prevent stall under certain circumstances by pushing the plane’s nose downwards. Boeing didn’t try to hide the system — it’s disclosed in the plane repair manuals — but they didn’t disclose it to pilots or make any kind of effort to train crew members on its existence. Boeing’s argument throughout this process has been that the 737 Max 8 is a perfectly safe plane and that all existing crew training is sufficient to respond to any emergency situation they might encounter…
There have been reports that Ethiopian Air Flight 302 “smoked and shuddered” before its plunge. If these prove true, it could point away from the MCAS system. It’s also possible that the MCAS system overrode any action the pilots were attempting to take to return the plane to proper control as a result of an engine or another component failure. Right now, we simply don’t know. Boeing is preparing a software update for the 737 Max 8, but that update was already in the works last month before Flight 302 fell out of the sky.
Reports I have seen stated that President Trump grounded the fleet. That makes it as much a political action as a technical one.
I suggest that we all wait until there are definitive statements of fact from investigative authorities before forming opinions. In my experience, and sadly it involves several accident investigations, they may be surprising.
Meanwhile, I am adding to my modest holding in Boeing stock because I believe in this, the last great American engineering/manufacturing enterprise–and the gold standard in commercial aviation.
Having no background in aviation, avionics, accident investigation, I’m the least qualified person to express an opinion and I know it.
I do know a little bit about systems complexity and the ways that things can go wrong. Perhaps Boeing in the current year may have gone just a bit too much down the Airbus route in its automation approach. Or even worse has gotten its piloting gestalt into a place where it’s neither fish nor fowl and therefore the worst of both worlds.
We’ll certainly be hearing more about this kind of stuff. Hell, the GEOTUS instinctively gets it.
But there’s a devil sitting on my shoulder and he keeps muttering sotto voce that certain avenues of enquiry will NOT be entertained, viz.: Third World Maintenance Standards, Third World Pilot Competence (two swallows do not a summer make… but…), Affirmative Action / H-1B hires in avionics software development / oversight, and the general spread of a corporate culture toxic to the dreaded white male (there, I said it) who designed and built the 707…747, etc.
My point is not to traduce any of the above categories of Human Biological Diversity. Getting to the truth is hard enough in a perfect world. Gets tougher when you have Lysenko running the department and entires areas of speculation are taboo.
In the mean time, anyone planning to take a position in Boeing stock would be well-advised to find a bar where pilots with relevant experience hang out and start buying them beers.
Boeing, a stock buying opportunity? Could be. It’s down $45. Some worry that Chinese made aircraft could step into the breach.
I thought the Lion Air crash wasn’t too complex, but we don’t have a report on it yet. So either it is complex (maybe because of fundamental stability issues) or there is some other reason it’s taking awhile.
Zek, I thought exactly the same thought. Low salary H-1B programmers developing Windows10 and avionics control programs. But Oldflyer is correct, we won’t know until the reports come out.
TommyJay, don’t read anything into “its taking awhile”. Unlike the media and politicians, the investigators will take the time to thoroughly evaluate all possible data before going public. I would be terribly disappointed if they were out there with conjecture at this point. I believe in Boeing long term, and I have no concerns about the Chinese replacing them The hard eyed people who buy airplanes for airlines understand value. Some will go for the short term, cheap option, and regret it; most will stick with the manufacturer with a long track record for excellence.
Zek, I do have some experience with third world maintenance and training standards,
and you raise very valid questions across the board. The concerns may, or may not, apply to the two airlines involved; but, I would wager that the oversight of them does not come close to the standards we expect. You also raise valid points viz a viz Boeing and Airbus. AB went the route of protecting pilots against themselves with technology a long time ago; and were generally applauded. Boeing has no doubt felt pressure from foreign airlines, and certification authorities to get on board.
Although some time conflicting reports are flying (no pun), as far as I know, neither Southwest nor American saw fit to ground their Max8 fleets unilaterally. If that is true, I consider it significant. Despite some conjecture, their fleets are small enough that grounding them would have minimal impact on their schedules.
Over dinner, my wife made much of reports that the Max8 is a totally different airplane, and was only called a 737 to save training costs. So what? Every manufacturer will try to sell each new innovation as a derivative on an existing airplane for the same reason. National certification authorities are responsible for evaluating the claims and making the determination. Apparently none; not the FAA, the British CAA, nor the French and German authorities challenged the supposition in regards to the Max8.
Just to clarify–every airliner built for decades has had a system to prevent stalls. In stage one, if the angle of attack (think air speed for simplicity) reaches a certain point that it approaches a stall the pilots yoke shakes rather violently; then if it continues closer to stall a system pushes the nose down decisively (a pilot cannot prevent this once activated) to prevent the stall. Every airline pilot in the world should have been exposed to this situation in training. The procedure is ingrained. Relax control pressures until the airplane has regained safe flying speed, then take measured actions to stop altitude loss. Basic airmanship.
There is absolutely nothing new, or mysterious about that. Airliners are not supposed to get close to a stall. In fact on pilot evaluations, reaching the second step is a disqualifying situation. Apparently, the system on the Max8 is more sophisticated, and as near as I can determine activates at an earlier point. Although a nose down pitch is not a new development, it would seem that the engineers decided that pilots needed a greater buffer, and the conditions that would activate the system at an earlier point were not incorporated into training. I find it ironic when engineers decide what pilots need; but, I am somewhat prejudiced. Unintended consequences. Kind of like government programs in general.
“…but they didn’t disclose it to pilots or make any kind of effort to train crew members on its existence…”
If true, this is utterly damning…
…and criminally negligent (especially if the company claim—that no extra pilot training was required—is verifiable, which it seems to be).
And it will be very expensive for Boeing.
Those people did not have to die.
I understand the “black boxes” have been flown to France for analysis, so with any luck there will be some preliminary answers soon.
Every airline pilot in the world should have been exposed to this situation in training. The procedure is ingrained. Relax control pressures until the airplane has regained safe flying speed, then take measured actions to stop altitude loss. Basic airmanship.
Air France 447 was an interesting variation on that.
At 02:10:05 UTC the autopilot disengaged because the blocked pitot tubes were no longer providing valid airspeed information, and the aircraft transitioned from normal law to alternate law 2.[48] The engines’ auto-thrust systems disengaged three seconds later. As pilot flying, Bonin took control of the aircraft via the side stick priority button and said, “I have the controls.” Without the auto-pilot, the aircraft started to roll to the right due to turbulence, and Bonin reacted by deflecting his side-stick to the left. One consequence of the change to alternate law was an increase in the aircraft’s sensitivity to roll, and the pilot’s input over-corrected for the initial upset. During the next 30 seconds, the aircraft rolled alternately left and right as Bonin adjusted to the altered handling characteristics of his aircraft.[49] At the same time he abruptly pulled back on his side-stick, raising the nose. This action was unnecessary and excessive under the circumstances.[50] The aircraft’s stall warning sounded briefly twice due to the angle of attack tolerance being exceeded, and the aircraft’s recorded airspeed dropped sharply from 274 knots (507 km/h; 315 mph) to 52 knots (96 km/h; 60 mph)
The input to the system confused the pilot, the least experienced of the crew.
Programming errors is an interesting thought.
Powered flight is very much a mystery. They can predict to some extent the stresses of air lift, but they do not understand the principles as much as it is expected by mainstream popular science. For example, airplanes only work on a fixed horizontal plane as measured by gyroscopes. It cannot work on an air sphere.
On a sphere of air, the airplane would constantly be nosing up and would have to nose down, to prevent stall and airspeed loss. Yet airplanes travel half way across the globe and the artificial horizon linked to the gyroscope does not change unless they bank or point up or down manually.
The math for airlift assumes the airplane is on a fixed horizontal plane. It has to in order to work.
oldflyer…”then if it continues closer to stall a system pushes the nose down decisively (a pilot cannot prevent this once activated) to prevent the stall.”
If I understand correctly, these “stick pusher” systems push the yoke forward so that the pilot will feel it move, and can override it by pulling back *hard* (something like 70lb force, IIRC)….is that correct? And the 737 Max system doesn’t do anything with the yoke, but rather affect the trim by moving the tailplane…which would not be as directly obvious.
Here is the actual FAA AIrworthiness Directive resulting from the Lion Air crash in Indonesia:
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/83ec7f95f3e5bfbd8625833e0070a070/$FILE/2018-23-51_Emergency.pdf
ymarsakar, What are you talking about?? From a physics standpoint you are talking nonsense. What “sphere of air”? Airplanes don’t fly inside a bubble. There’s no “fixed horizontal plane” needed.
Maybe you need to go back and review basic Newtonian physics. There are 4 forces acting on an airplane: lift, drag, thrust and gravity. The plane’s motion is a result of the vector sum of those forces; setup any coordinate system you like (put it on Mars for a plane flying on earth!) and the result is the same.
And if you are talking about lift generation from a wing..that also is coordinate frame independent. There are two factors contributing to lift: Bernoulli low pressure generation which is highly dependent on wing profile, and the more important acceleration of the airstream in a different direction, which from Newton 3 generates a reaction force, ie “lift”. This second effect is why angle of attack is so important. Want empirical proof? On the next nice day stick your hand out the car window while moving at 50mph. Keep you hand horizontal, then tilt your hand slightly upward to the oncoming air stream…voila! lift! Now continue to increase the angle of attack; at a critical angle your hand will stall. The only important direction is the wing’s angle with respect to the relative air velocity vector; ie angle of attack. That “relative air velocity vector” is a summation of the air’s velocity vector relative to a stationary wing and the wing’s own velocity vector. Easy example: Wind blowing from the north at 20kts, wing moving north at 80kts; net air velocity vector is 100kts relative to wing. Which is why planes always try to takeoff and land into the wind. And as Oldflyer will tell you, crosswind landings are “fun”. All planes also have a restriction on the maximum crosswind component of the air vector that they can safely land. But I guess the engineers who designed the planes and calculated that value still regard lift as a mystery.
Having spent over 40 years playing with computers, including over 2 decades of programming, the FIRST place to look for human error should be the software. Even the best programmers in the world, which does NOT include me, leave undetectable bugs in their code.
It might be called Computer Science. But it isn’t.
Barry Meislin, your comment is the type that I abhor. Your are throwing mud with very little justification. As I have said repeatedly, it will be quite some time before all of the data is analyzed, and don’t be surprised if there are surprises. There often are.
Black boxes–which are not black of course–sent to France, home of Boeing’s major competitor, the state subsidized Air Bus company–for analysis? Hmm.
David Foster; true in theory. I instructed fairly extensively in airplanes, as well as simulators, with the “old style” stall prevention system. I never yet saw a pilot who could react and over ride the pitch down. On test flights we were required to exercise the pusher, so I felt it. It occurs suddenly, and the force is strong, although I never had a figure in mind. I do not know whether the yoke displaces in the Max8. Is it verified that it doesn’t? That would be rather surprising.
In Airbus, there is no yoke and all controls are electronic (fly by wire) so there are little to no cues to the pilot. Boeing did not go that route. Although they have incorporated partial electronic controls in the Max8, my understanding is that the pilots have more direct control; and I also understand that pitch control is not part of the system. I wonder if people are confusing the Boeing system with that of Airbus.
Too many unknowns; too much speculation. Airplane grounded until–what?– corrective action. Political reaction to hysteria?
Ditto, Tuvea. I don’t know nuthin about no airplane or flying one, but I know something about software. The more complex the task you’re programming for, and the wider the possible variance in the circumstances in which it is performed, especially those involving human input, the less possible it is for the programmer(s) to anticipate every potential trouble scenario. There’s a point where it’s simply IMpossible.
The words “recent software update” in the news stories about this gave me a chill. And I bet there are some developers at Boeing who started shaking. I once did development on o.s. components in which an error would bring the whole system down, and I well remember the fear when customer support reported a system crash in the field.
“It might be called Computer Science. But it isn’t.” Heh. The science part is the part that’s comfortably abstract–formal grammars and stuff like that.
Remember back in 2013, when there were problems with the battery system on the 787 Dreamliner? I ran into an appalling comment thread (on Yahoo) which was all about *blame*…some people blamed “parts made in China”, some blamed union labor in Seattle, some blamed non-union labor in South Carolina, some accused FAA inspectors of accepting bribes from Boeing, some blamed Obama….I wonder if we’re going to see that sort of thing again here.
See my 2013 post on the 787 issue and these reactions: The Dream(liner) and the Nightmare(of Social Toxicity).
https://chicagoboyz.net/archives/34475.html
Even the best programmers in the world, which does NOT include me, leave undetectable bugs in their code.
It’s the Peter principal, every programmer rises to the level at which they make mistakes. Large software programs are incredibly complex, we are fortunate that most bugs don’t lead to crashes. My understanding is that critical software is developed in a far more demanding environment than the usual: multiple line by line code reviews and extensive testing. I expect it takes a certain type of personality as well as talent to program in that way.
As I’m entering retirement, I’m also engaging in my other passion aviation by volunteering at a air museum. One of my new colleagues is an ex Pan Am pilot who flew everything right up to the 747. He just sent me this which speaks directly to the software issue:
Subject: Boeing 737 Max 8
Boeing to Make Key Change in 737 MAX Cockpit Software–7th UpdateBY ANDREW
TANGEL AND ANDY PASZTOR | DOW JONES & COMPANY, INC. – 11 MINUTES AGO
Boeing Co. (BA) is making an extensive change to the flight-control system
in the 737 MAX aircraft implicated in October’s Lion Air crash in Indonesia,
going beyond what many industry officials familiar with the discussions had
anticipated.
The change was in the works before a second plane of the same make crashed
in Africa last weekend — and comes as world-wide unease about the 737 MAX’s
safety grows.
The change would mark a major shift from how Boeing(BA) originally designed
a stall-prevention feature in the aircraft, which were first delivered to
airlines in 2017.
U.S. aviation regulators are expected to mandate the change by the end of
April.Boeing (BA) publicly released details about the planned 737 MAX software
update on its website late Monday. A company spokesman confirmed the update
would use multiple sensors, or data feeds, in MAX’s stall-prevention
system — instead of the current reliance on a single sensor.
The change was prompted by preliminary results from the Indonesian crash
investigation indicating that erroneous data from a single sensor, which
measures the angle of the plane’s nose, caused the stall-prevention system
to misfire. Then, a series of events put the aircraft into a dangerous dive.
Focus on the update has taken on greater urgency as aviation regulators and
airlines around the world have grounded their MAX fleets, following the
Ethiopian crash over the weekend — despite no links being made between the
two crashes by investigators.
The MAX software change is expected to take about an hour for each plane, a
Boeing (BA) spokesman said Tuesday. He declined to offer other details about
how the system would weigh the multiple data inputs.
“For the past several months and in the aftermath of Lion Air Flight 610,
Boeing (BA) has been developing a flight control software enhancement for
the 737 MAX, designed to make an already safe aircraft even safer,” Boeing
(BA) said late Monday in a statement.
The FAA has decided to allow the 737 MAX to continue flying, a break with
counterparts in countries including the U.K., Australia and Singapore, which
grounded the model in recent days.
The investigation into the Oct. 29 Lion Air crash is continuing, but has
focused on the stall-prevention system, apparent maintenance lapses and
potential pilot error. Investigators have revealed little about the
circumstances leading up to the Ethiopian crash, but have found cockpit
voice and data recorders.
When the plane was first designed, engineers determined that using a single
sensor — measuring what is technically known as the angle of attack —
would be simpler and was in line with the plane maker’s long-held philosophy
to keep pilots at the center of cockpit control, a person familiar with the
matter said.
That earlier design of the system, known as MCAS, has puzzled some pilots
and safety experts, who wondered why the system didn’t rely on multiple
feeds.
Mike Michaelis, chairman of the safety committee at American Airlines Group
Inc.’s pilot union, welcomed news of the coming Boeing (BA) software fix.
“That’s the way it should have been in the first place,” he said.
In the wake of the Lion Air crash, Boeing (BA) and the FAA emphasized that
an existing procedure allows pilots to disable the MAX stall-prevention
system when flying the airplane. U.S. airlines and unions have since
expressed confidence in their pilots to safely operate the airplane.
A software fix to the MCAS flight-control feature by the FAA and Boeing (BA)
had been expected early in January, but discussions between regulators and
the plane maker dragged on, partly over differences of opinion about
technical and engineering issues, according to people familiar with the
details. Officials from various parts of Boeing (BA) and the FAA had
differing views about how extensive the fix should be.
U.S. officials have said the federal government’s recent shutdown also
halted work on the fix for five weeks.
The FAA concluded the delay was acceptable because its experts agreed with
Boeing (BA) that there was no imminent safety threat, according to one
person briefed on the discussions. The FAA also determined that steps taken
after the Lion Air crash to inform pilots world-wide about the system’s
operation were adequate to alleviate hazards.
Since the 737 MAX is a derivative of an earlier model, certification rules
allowed regulators to give the plane maker credit for the safety record of
those earlier planes. And to some extent, government and industry officials
have said, government scrutiny of certain systems typically is less intense
for derivatives than for brand-new designs.
With design work on the original 737 planes dating back some five decades,
“there is no other jet in the world that has so many derivatives over such a
long period of time,” according to John Cox, an industry consultant and
former senior safety official for North America’s largest pilots union.
Boeing (BA) also told the FAA it had extensive experience with the
reliability of the same type of sensors on other models, according to
industry officials familiar with the details, and that using multiple
sensors to feed the flight- control system would have been more complex.
A Boeing (BA) spokesman didn’t immediately respond to a request for comment
regarding discussions about the fix.
The anticipated fix also will limit the extent of the flight-control
system’s downward push on the plane’s nose. And it will rely more on
technical safeguards than memorized pilot responses if the system misfires.
Boeing (BA) said the change would come with updates to pilot displays,
operation manuals and crew training.
Write to Andrew Tangel at Andrew.Tangel@wsj.com and Andy Pasztor at
andy.pasztor@wsj.com
(END) Dow Jones Newswires 03-12-19 1659ET Copyright (c) 2019 Dow Jones &
Company, Inc.
Thanks, physicsguy. I wonder if the 737MAX planes on the ground in the US will stay there until late April. That’s quite a financial hit for their owners. If it’s the safest thing to do, then I’m all for it, but Boeing is going to pay big time.
What “sphere of air”? Airplanes don’t fly inside a bubble. There’s no “fixed horizontal plane” needed.
Your education on how airplanes work is severely lacking. You need air flight instruction manuals as well as Boeing engineering basics before you can understand these issues at a level enough to have a view that can make sense.
Easy example: Wind blowing from the north at 20kts, wing moving north at 80kts; net air velocity vector is 100kts relative to wing. Which is why planes always try to takeoff and land into the wind. And as Oldflyer will tell you, crosswind landings are “fun”.
Check the velocity difference between Earth rotation at the equator vs the tropic of cancer, if you want to know what “fun” is. The differential is far higher than 100 kts. I doubt an explanation of this is comprehensible to you at this time.
More comedy. Spheres within spheres and, wait for it, N Tesla on sciency things. Well off to work, to work with engineers, who make things that work in the actual world, not the Y world.