Ethiopian Airlines Crash and the 737 MAX

Ethiopian Airlines CEO Tewolde Gebremariam at the 737 crash site.


UPDATE: March 13, 2019

The F.A.A. has announced the grounding of all 737 MAX-8 jets in the United States, effective immediately.

This comes after many other nations had already announced a grounding (see post below). The reason for the delay was in part because of the difficulty in proving a link between the crash of the Lion Air 737 MAX in October, and Sunday’s similar accident in Ethiopia. Did they same system malfunction that led to the Lion Air crash also lead to the Ethiopian disaster? The voice and data records have not yet been analyzed, but indications certainly suggest a connection, and the F.A.A.’s decision, while perhaps a bit tardy, isn’t surprising.

The global fleet of existing MAX jets is very small — only around 350 planes. This makes it relatively painless for carriers to remove the jet from service without serious disruptions to their operation.


ORIGINAL POST: March 12, 2019

ON SUNDAY, an Ethiopian Airlines 737 MAX crashed after takeoff from Addis Ababa, killing 157 people from more than thirty countries.

The big story is how this accident relates, or doesn’t relate, to last October’s crash of another 737 MAX in Indonesia, and what that potentially means for airlines and passengers the world over. In the October disaster, 189 people perished after Lion Air flight went down near Jakarta, Indonesia, under eerily similar circumstances. Both planes were effectively brand new 737 MAX jets. Both crashed shortly after takeoff following a loss of control.

Preliminary reports of the Lion Air crash point to a flaw in something called MCAS, which stands for Maneuvering Characteristics Augmentation System, an automatic system designed to keep the plane’s nose from pitching up at too high of an angle. The problem occurs when faulty data is generated by the plane’s angle of attack indicator. The indicator is a small, wedge-shaped sensor near the plane’s nose that helps warn pilots of an encroaching aerodynamic stall — i.e., a dangerous loss of lift that results from flying too slowly or too steeply. The faulty system senses a stall when there isn’t one, triggering the plane’s stabilizer trim — stabilizers are the wing-like horizontal surfaces beneath the tail — to force the nose down. Essentially, the Lion Air pilots lost control of their ability to maintain level flight.

Did the same thing happen again?

At this point it’s impossible to know, but it’s pointing in that direction, and a growing number of countries, including now the United States, are concerned enough to have ordered the grounding or banning of all 737 MAX flights.

For pilots, dealing with the unwanted nose-down command would be, or should be, straightforward. The MCAS commands, faulty or not, can be overridden quickly through a pair of disconnect switches. Why the Lion Air pilots failed to do this, if in fact they did, is unclear, but unaware of the system’s defect in the first place, we can envision a scenario in which they became overwhelmed, unable to figure out in time what the plane was doing and how to correct it.

From that point forward, however, every MAX pilot out there would have been familiar with the problem, and ready to react accordingly should they face it. “Though it appears there’s a design flaw that Boeing will need to fix as soon as possible,” I wrote in November,“passengers can take comfort in knowing that every MAX pilot is now acutely aware of this potential problem, and is prepared deal with it.”

Or so it seemed. The Ethiopian accident, though, makes us wonder. With the Lion Air crash fresh on any 737 MAX pilot’s mind, how did this happen? Did a disconnect of the MCAS somehow not work? Was the crew so inundated by a cascade of alarms, warnings, and erratic aircraft behavior that they failed to recognize what was happening? Or, was the problem something else completely? This is the most perplexing part of this whole unfolding drama.

We don’t yet know, but investigators do determine a link, there’s a quite a bit at stake — for the plane’s manufacturer, for the world’s airlines, and for the traveling public. Boeing will need to implement a fix, be it a hardware solution, a software solution, or both, in a process that is likely to take weeks if not longer.

Ethiopian Airlines 737 MAX

Founded in 1945, Ethiopian Airlines is the largest carrier in Africa. Westerners hear “Ethiopia” and tend to make certain, unfortunate associations, but this is company with a proud history and a very good safety record. It flies a state-of-the art fleet, including the Boeing 787 and A350, on routes across four continents. Its training department, the Ethiopian Airlines Aviation Academy, has been training pilots for 55 years. Ethiopian’s pilots are distinguished by their handsome, olive green uniforms.

The captain of the doomed flight ET302, Yared Getachew, was a graduate of the highly competitive Ethiopian Airlines Aviation Academy, and had more than 8,000 flight hours — a respectable total. “Yared was a great person and a great pilot. Well prepared,” a former Ethiopian Airlines training captain told me.

The first officer, on the other hand, had a mere two-hundred. Airline training is intensive, and as I’ve written in the past, the raw number of hours in a pilot’s logbook isn’t always a good indicator of skill or talent. Nonetheless, if indeed that number is correct, that’s pretty astounding. By comparison, the typical new-hire at a U.S. major carrier has somewhere on the order of 5,000 hours. Whether the first officer’s lack of experience had anything to do with the accident, however, is unknown.

The 737 MAX is the newest variant of Boeing’s venerable 737 line, which first flew in 1967. The largest MAX operators in the U.S. are American Airlines and Southwest. Other customers include Alaska Airlines, Air China, Norwegian, FlyDubai, China Eastern and China Southern. The type is most easily recognize by its 787-style scalloped engine nacelles, which earlier 737s do not have.

The outright grounding of an aircraft model is unusual, but not unprecedented. New jets are sometimes beset by technical issues in their early days of service. Normally these problems are minor, if expensive, nuisances (engine problems that plagued the first 747s, for example), but there have been catastrophic instances too. We remember the Comet, the world’s first commercial jet, and the three stress-crack disasters that led to its grounding and redesign. The McDonnell Douglas DC-10 was plagued by troubles from the start, including a poorly designed cargo door that killed 346 people in the horrific Turkish Airlines crash in 1974. Later, in 1979, all DC-10s in the United States were grounded by the FAA after crash of American Airlines flight 191 at O’Hare — to this day, the deadliest crash ever on U.S. soil. More recently, the 787’s debut was marred by a series of battery fires.

This isn’t even the first setback for the 737. Earlier model 737s were plagued by a rudder problem that resulted in at least one deadly crash (USAir outside Pittsburgh in 1994) and forced a redesign of the rudder servo system.

For the airline passenger, these can seem like scary times. Air crashes, perhaps more than any other type of catastrophe, have a way of haunting the public’s consciousness, particularly when the causes are mysterious. My best advice, maybe, is to take a step back and look at this through a wider lens. The fact is, Lion Air and Ethiopian notwithstanding, air travel has never been safer than it is today. Two fatal crashes in five months is tragic, but in decades past it wasn’t unusual to see ten, fifteen, or even twenty air disasters worldwide in a given year. Nowadays, two or more is downright unusual. Here in the United States there hasn’t been a large-scale fatal crash involving a mainline carrier in nearly twenty years — an absolutely astonishing statistic. There are far more planes, carrying far more passengers, than ever before, yet the accident rate is a fraction of what it once was.


Thumbnail photo by Michael Tewelde/AFP

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48 Responses to “Ethiopian Airlines Crash and the 737 MAX”
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  1. Tom Dietsche says:

    If this MCAS software depends on just one sensor to work properly (or not, as may be the case here), then that is a “single point of failure”. As good old Wikipedia says, “A single point of failure is a part of a system that, if it fails, will stop the entire system from working. SPOFs are undesirable in any system with a goal of high availability or reliability…”. No kidding!!
    So, assuming that is the case here (no secondary sensor data or other method of handling bad sensor data), why was this allowed? And, secondly, how many other SPOFs are there in these 737 Max planes, or other models?

  2. Tom in Vegas says:

    Outstanding article in the Seattle Times today about the development and FAA certification process for the 737 Max. Should, if accurate, address the issue. Outstanding. Would like Patrick to comment on it.

  3. Jim M says:

    I keeping hoping someone will publish a correction and amend the co-pilot’s 200 hours to “time in type” instead of total time. It’s hard to conceive of being qualified to fly a 737 in that amount of flight time even if it’s all instruction time. Hard enough to just get a commercial, multi-engine, instrument rating in 200 hours.

    An article on the subject of international copilot requirements would be interesting.

    • Rod says:

      Agreed that an article would be interesting, for light needs to be shed on this subject. I have twice the number of hours as the Addis FO, but all VFR single-engine hours accumulated as a weekend pilot: pretty useless on the MAX, eh?

      “Sully-upon-Hudson” (as Patrick calls him) made similar outraged remarks in an article I read about having a 200-hour FO. They were rebutted by two airline pilots as follows:

      “I’m sick of this tired old argument. You get your fATPL [Frozen Air Transport Pilot License] at 200-250 hours. In the States, you then muck around to get to 1500 before you can get an airline job. Lots of people instruct on a Cessna or Piper to build time. Hours on these aircraft contribute little to your ability to fly a complex jet in a commercial environment. In fact bad habits and attitudes acquired through years of general aviation flying may diminish professional capabilities of pilots. The fact remains that most parts of the world hire 200-hour cadets and have exceptional safety records because the quality of training is good and geared toward professional standards.”

      “There are people with barely more than 200 hours flying nuclear armed military aircraft over your country every single day. If the training is good then it’s a total non issue.”

  4. I discovered AskThePilot through the Atlantic article on the Ethiopian 737 MAX 8 crash by James Fallows. I was a private pilot from 1976 to 1986 holding SE & ME Land, Instrument Airplane, and CFI certificates. I was gratified to see that James Fallows and you have brought fact-based, rational discussion of the 737 MAX 8 air crashes to the public media, which I hope will overcome the fear mongering media frenzy being spewed out by the “mainstream” media outlets to increase readership but leaving the non-aviation public feeling more distressed and fearful. Keep up the flow of “real” news.

  5. Michael Spencer says:


    The Ethiopians elected to send the two ‘black boxes’ to the Bureau d’Enquêtes & d’Analyses (France). They explained that the French agency might be a bit more neutral, as Boeing is in America; an opinion unfair to FAA, in my view, which could be blindly chauvinistic..

    Could you comment on the French as well as other agencies? How they compare to the FAA, in reputation as well as actual ability? Googling “reputation Bureau d’Enquêtes & d’Analyses” isn’t helpful.

    I’d expect the French agency to be world-class. Are they? What other agency in the world compares favorably to FAA? Am I correct that FAA is the ‘gold standard’? What of the Russians, or the Chinese, or the Brits, Canadians, Australians- that’s only the more developed countries. Are there labs in Africa, for instance, or non-Chinese Asia, that are capable? What of India?

    This entire episode is quite troubling, for sure. And thanks!

    • Rod says:

      Patrick is, as always, far more qualified than I to answer this. Just remember that the Ethiopians (as far as I know) haven’t handed over the Actual Investigation to the French. They’ve merely availed themselves of their technical equipment and expertise. I’m sure Boeing (as manufacturer) and the FAA (as certifier) will be looking over their shoulder.

      The FAA is a federal agency. Under the current administration, the websites of the Environmental Protection Agency, the Energy Department, the State Department, etc. were promptly scrubbed clean of references to climate change, greenhouse gases and clean energy.
      What does that tell you?

      So who trusts the US authorities to do this analysis with flawless professionalism? Clearly not the Ethiopians.

    • Simon says:

      I’d be wary of the FAA for the simple fact that they are both the ‘regulator’ and charged with promoting air travel and aviation. It’s an impossible situation to be in and I believe Our Favorite Pilot has also written about that issue.

      I don’t have any special distrust in the FAA, but as others have pointed out, government agencies have been politicized by the current administration and that does leave a bad aftertaste. In general I wonder if something like CDR/CVR analysis would be better handled by the NTSB with all their experience, plus them not also being mandated to promote aviation and airline manufacturers like Boeing at the same time as they’re investigating their products.

      I almost feel like it might be good practice in general to always go the investigators of a third country for technical analysis. Just like sending an Ethiopian MAX 8 recorded to France for example. Or in an Airbus crash in Japan sending the data recorders for analysis to the NTSB.

    • Speed says:

      Don’t confuse the FAA with the NTSB. Investigations are done by the NTSB.

      “In 1967, Congress consolidated all transportation agencies into a new U.S. Department of Transportation (DOT) and established the NTSB as an independent agency placed within the DOT for administrative purposes. In creating the NTSB, Congress envisioned that a single organization with a clearly defined mission could more effectively promote a higher level of safety in the transportation system than the individual modal agencies working separately. Since 1967, the NTSB has investigated accidents in the aviation, highway, marine, pipeline, and railroad modes, as well as accidents related to the transportation of hazardous materials.

      In 1974, Congress reestablished the NTSB as a completely separate entity, outside the DOT, reasoning that ” …No federal agency can properly perform such (investigatory) functions unless it is totally separate and independent from any other … agency of the United States. ” Because the DOT has broad operational and regulatory responsibilities that affect the safety, adequacy, and efficiency of the transportation system, and transportation accidents may suggest deficiencies in that system, the NTSB’s independence was deemed necessary for proper oversight. The NTSB, which has no authority to regulate, fund, or be directly involved in the operation of any mode of transportation, conducts investigations and makes recommendations from an objective viewpoint.”

      • Rod says:

        Speed, your link doesn’t work for me. I have every respect for the NTSB, which spoke the Truth to the FAA after the Valujet crash, for example. But these are strange times. Every entity dependent on federal government funds will somehow appear suspect in certain eyes.

        Anyway, the Bureau d’Enquêtes et d’Analyses (BEA)– some people following the AF447 investigation quipped that the A stood for Airbus — is no more in charge of the investigation than the NTSB would have been. I believe the Ethiopians are formally in charge (it being an Ethiopian-registered aircraft that crashed on Ethiopian soil). They just don’t have the highly specialized facilities to analyse the recorders.

        So let’s say that that the choice of France over the US is a symbolic protest at being sold a bill of goods: am airplane that supposedly required little extra training or experience to fly, relatively speaking.
        The Ethiopians don’t for the moment know any better than you or I what really happened, but they probably feel screwed by Boeing.

  6. Ken says:

    I saw some flight tracking data that had the air speed at >300 kts! I thought it might have been a mistake, but now I just read elsewhere that the pilot reported higher than expected speed.

    Sounds like MCAS possibly kept throttle at TOGA while pushing the nose down. Would a pilot even be able to take time away from the yoke to shut off the MCAS. Would a very inexperienced 1st officer be able to turn it off in an emergency?

    • Speed says:

      From the Atlantic article linked below …

      “The Captain immediately disconnected the autopilot and pitched into a climb. The remainder of the flight was uneventful.”

      Autopilot disconnect is generally performed using a switch on the yoke. Disconnecting the autopilot also disables MCAS. To the best of my knowledge the MCAS does not control the throttles.

  7. Speed says:

    Gimlet Winglet wrote, ” … I’ve seen the first 3 minutes of the flight’s airspeed and altitude data as measured by ground radar … ”

    Ground radar can measure ground speed. If the wind speed and direction is known at the aircraft’s altitude, airspeed can be calculated.

    • Gimlet says:

      Your point is valid that ground radar sees groundspeed. The air temp at takeoff was 70 Fahrenheit and wind at 10 knots. The speed readings from ground radar do not show any sudden shifts in the first 3 minutes as if the plane got into some different wind at elevation, and indeed the plane never got higher than 1400 feet above runway elevation.

      So my questions remain, is 383 kts +/- 10 kts a normal speed for a 737 3 minutes after takeoff, and what would be considered normal flap settings and duration for a fair weather takeoff at 7625 feet elevation and a presumably loaded but not at the limits plane?

      • Speed says:

        Gimlet asked, ” … is 383 kts +/- 10 kts a normal speed for a 737 3 minutes after takeoff … ?”


        CFR says …
        “§91.117 Aircraft speed. (a) Unless otherwise authorized by the Administrator, no person may operate an aircraft below 10,000 feet MSL at an indicated airspeed of more than 250 knots (288 m.p.h.). (b) Unless otherwise authorized or required by ATC, no person may operate an aircraft at or below 2,500 feet above the surface within 4 nautical miles of the primary airport of a Class C or Class D airspace area at an indicated airspeed of more than 200 knots (230 mph.).”

        • Gimlet Winglet says:

          Your reply is still non-responsive: The plane was more than 4 nm from the airport at the point where it reached 250 kts. The plane’s ground speed vs time tracks with other 737 max 8 flights departing from Addis Ababa. If the plane had followed a normal climb path it would have been both over 10,000 ft MSL and 2500 ft above the local terrain.

          So, unless I’m told otherwise, 383 kts is not an “abnormal speed” for 3:00 minutes into a flight, unless you have failed to climb. The plane did not have an “abnormal speed” problem, it had an abnormal altitude problem. Yes, if the pilots intended to fly at low altitude they should have throttled down. The had no such intention.

  8. Speed says:

    James Fallows has a piece in The Atlantic about ASRS reports from 737 MAX pilots.

    “Here’s What Was on the Record About Problems With the 737 Max”

    “While the fundamentals remain unknown, here are some relevant primary documents. They come from an underpublicized but extremely valuable part of the aviation-safety culture. This is a program called ASRS, or Aviation Safety Reporting System, which has been run by NASA since the 1970s. That it is run by NASA—and not the regulator-bosses at the FAA—is a fundamental virtue of this system. Its motto is “Confidential. Voluntary. Nonpunitive.””

    • Rod says:

      Thanks, Speed. I remember ASRS from pre-internet days — a blue paper you could get in the mail.

      Yes indeedy — “I am left to wonder: what else don’t I know?” Even if the Ethiopians were to emerge with little credit (we’ll see, we’ll see), the fact remains that, for commercial gain, Boeing was damn economical with the truth trying to sell airliners to customers by representing them as just (yet) another step in the endless 737 chain — another bit of cockpit familiarization. No expensive retraining on completely new systems.

      I knew I’d seen mention of autothrottles, and wonder if this could have a bearing on speed mysteries. (We don’t yet know what was going on up there. But suppose it was several things and the captain, with a 200-hour FO, was basically alone to face them all.)

      Finally, Fallows doesn’t wish to prejudge the FAA. I, however, will note that all federal agencies in the US these days seem to be undergoing a process of ‘ideological cleansing’. So why not protectionist cleansing too?
      The US basically waited until virtually the Whole Rest of the World had grounded the MAX before doing so itself. That does not inspire confidence. The Ethiopians strikingly did not bring the recorders to the US for analysis. I’d say loss of credibility has a lot to do with that.

  9. Gimlet Winglet says:

    There’s an NY Times report that claims “return after three minutes as the aircraft accelerated to abnormal speed”, without explaining what is meant by “abnormal speed”. Now, I’ve seen the first 3 minutes of the flight’s airspeed and altitude data as measured by ground radar, and the airspeed was NOT oscillating, but increasing at what appears to be a normal, constant rate. At 3 minutes into the flight the airspeed was 383 knots. Can anyone indicate if this is an unusual speed at that point?

    Also, a semi-related question: given that the runway elevation is 7625 feet, on takeoff would they be likely to deploy less flaps than usual and retract them sooner than at sea level? (Obviously we don’t know if the plane was “heavy”, though the passenger count indicates not a full flight.)

  10. Alan Dahl says:

    Let’s be a little careful of jumping into Boeing’s back until we know all of the facts. There are reports that the root cause could have been unreliable airspeed indications which combined with the mountainous terrain and a single pilot that was pretty much alone in the cockpit (because you or I would be as much use in an emergency situation) could have resulted in a loss of situational awareness and controlled flight into terrain. One of the reasons that flying is so much safer now is because of CRM, crew resource management, and that means pilots sharing the burden equally when an emergency occurs. I can’t see a rookie copilot with less time than a Cessna 150 pilot with a year under his belt being much help in this situation and perhaps could even have been a hinderance.

  11. One other thought/question. How come Boeing puts so much into all of the variations of the 737? They are trying to make various changes to that airframe be all of the planes they have ever made other than wide bodies….and even that – the larger variants compete with 757s and 767s nearly for quantity of seats. Why abandon the 757/767 programs? I suppose it is cheaper to make one model that suits all – and perhaps it is easier for airlines to train – but that being said – I cannot imagine there is much in common with earlier 737s and the newest MAX versions regarding pilot training. Your thoughts…?

  12. Captain Patrick – I knew you would pen a well-thought out and informative article about this situation. Yes – very sad and very tragic. But when you look at the overall picture the flight any of us take on any given day is probably safer than how we go to the airport or how we walk thru a city. I shared this on a number of social media pages. Nicely done. – Mike

  13. Ben says:

    There is a part of me with this still unfolding story that feels that Boeing has finally completely crossed the line with remaking and re-engineering the 737 to death with the MAX here. The 737 has been spliced into roles the were previously done by 3 other jets exclusively in the 707, 727, and 757. Boeing completely bit the low cost carrier bug here, and now it is finally coming back to haunt them with these two eerily similar crashes just 5 months apart. This could likely do catastrophic short, medium, and long term damage to Boeing if they are not careful, and it will get worse before it gets better.

    • Ababu says:

      Ditto Ben.

      Totally agree “Boeing has finally completely crossed the line with remaking and re-engineering the 737 to death with the MAX here. The 737 has been spliced into roles the were previously done by 3 other jets exclusively in the 707, 727, and 757. “

  14. Dick Waitt says:

    What we need here is a bit of Patrick’s common sense, especially as related to the chances of anything going wrong, even if it is eventually shown that this new system is somewhat at fault.

    What I’m saying is that, until this recent happening there have been probably thousands of totally safe flights of various versions of the 737MAX in its various versions. All were safely done (unless there have been other incidents of which we are unaware).

    Yes, it is a serious problem which needs to be addressed, but let’s not be expecting that the flight YOU are on will be the next failure.

  15. Lee says:

    First of all, any pilot flying a Max would know at this point how to disconnect the autopilot even if it’s a multi step process that wasn’t explained to begin with.
    Second, an Ethiopian farmer who witnessed the crash said there was fire and debris coming from the aircraft while still aloft. Which would have nothing to do with the autopilot.
    Based on that I could see why the FAA didn’t ground the planes.

  16. David says:

    Reminds of the saying never buy a car in its first year of production

  17. Richard Hartman says:

    I have seen one report that mentions smoke coming from the Ethiopian plan before the crash — this may indicate that something other than the MCAS was at fault this time.

  18. Michael Kennedy says:

    Not criticizing Ethiopia but one of the things we did in the sims at my last US airline before I retired was have the crews flew the plane with the trim completely AFU. (Some crews crashed but they got additional training) It’s a scary thing when the plane you thought you knew tries to kill you.

    Patrick, may remember the lovely SAS (stall avoidance system) in the Metroliner? Turning it off was the first thing you learned how to do.

    In my opinion Boeing screwed up by not telling the crews more about the MCAS and my guess is that the FAA is going to mandate lots of additional training. Which is how it should be.

    • Rod says:

      All bets payable only after fully functioning recorders are analysed and the investigation reaches some stage of certainty. Hey, maybe the Ethiopians did drop the ball — either in terms of faulty training or 200-hour FOs, or both. But that would hardly rehabilitate the MAX in the public mind.

      Or in the minds of some pilots, it seems. The complaints I’ve seen published from the FAA database, made by MAX pilots after Jakarta but before Addis, sound outraged and suspicious. Autothrottles too, I’ve read.

  19. Sharon Murphy says:

    I hate to fly, and the older I get, the more anxious I become when I have to fly again. These tragedies only make me feel worse. However, your articles always put things in perspective, and ease my fears about flying. Thanks for sharing your knowledge and insight.

  20. John Robertson says:

    Would Captain Sullenberger have been successful landing a 737 Max 8 on the Hudson?

  21. Alex Pun says:

    I feel like, for once, evidence and data (lack thereof) doesn’t matter this time(!). Now bear with me here… I know this site is, if anything, all about fact.
    By grounding the planes, Is the whole world jumping to conclusions? Yes. But somehow the way things evolved, this is no longer purely a question of 737Maxs’ airworthiness. Instead it seems to get more political or even GEOpolitical by the day. As in, FAA is now losing its public trust, and perhaps over the past four days it is deemed internationally irrelevant (even if just temporarily so). Had it been handled better perhaps we could have stick to pure facts (about the two crashes), but this is the Trump administration we are talking about. Not trying to be too political here: it is a bipartisan consensus that his tweeting often get himself and all of us into trouble. Boeing is certainly not helping by calling the president… Seriously, what good does that do?
    The fact that I am able to discuss FAA’s decision without mentioning a single technical data shows what kind of time we are in.

  22. Simon says:

    Patrick, IIRC the AOA sensor was already a serious concern in AF447. Considering that this element is often described as a simple weather vane, yet this “simple” weather vane seems to also be prone to failure/error. Considering how important AOA signals are, is it possible these devices need to be throughly reengineered or otherwise, an alternative developed?

    • Matt Lyons says:

      Simon, the automation issue which led to the demise of AF447 was related to the failure of the pitot tubes (which use barometric pressure to determine the speed of the aircraft) not the angle of the attack sensor which measures the pitch of the aircraft. I’m surprised that Patrick did not mention the changes to the 737 8/9 MAX family of aircraft that necessitated the use of the MCAS software.

      Since the mid-2000s when oil prices became unstable, fuel efficiency has been the name of the game for commercial airlines, particularly in the U.S. Essentially, to make to the aircraft more fuel efficient than the previous generation, Boeing opted for a larger engine design, that while 14% more efficient, could only be accommodated by putting it further forward of the wing.

      This change was crucial since it altered the fundamental aerodynamic characteristics of the aircraft and the plane now had a tendency to pitch up during certain maneuvers. Enter MCAS as a software solution to address this design flaw which is unique to the 737 8/9 MAX series of aircraft. Boeing apparently did not think pilots needed to know about the software, which automatically adjusts the trim when it perceives the angle of attack to be too high, and did not issue an advisory bulletin as to how to disable it until *after* the Air Lion crash last October.

  23. Lyle says:

    The fact they had very experienced pilots flying manually or switching to autopilot when the antistall system kicked in suggests to me that due to poorer performance or undue restrictiveness of the automated flight parameters, (max vs ng) the pilots not being aware or trained climbed too rapidly for the Max.

  24. Mike says:

    Re: Ethiopian disaster

    You said in your Lion Air crash article: “The MCAS commands, faulty or not, can be overridden quickly through a pair of disconnect switches.”

    Surely (and if not, why not?) they can JUST SHUT THE DAMN THING OFF and fly the freakin’ plane until they figure this out! Not an Airbus so it is not totally fly by wire/software correct? Please err on the side of safety and sanity Boeing.

    Probably will when the next one happens. When, not if, unless they’re lucky.

    Millions of autonomous cars on the road soon? Yeah, right.

  25. Avery Greynold says:

    Was this a Boeing-engineered over-reaction to Air France Flight 447, where a couple confused pilots stalled a perfectly good A-330 into the Atlantic? Allowing an AOA system to overide them would have saved 228 lives that day. But putting all their eggs in one sensor’s basket may end up being even more costly.

    • Mark Maslowski says:

      I believe MCAS was installed because Boeing stretched the 737 for MAX, which changed the pitch characteristics, but they didn’t want to have to retrain those who were proficient on older models of the 737. Ironically, MCAS was supposed to be a safety net.

      • Rod says:

        Yes, pitch-up motivated MCAS, but not because of stretching the 737 (which Boeing has done endlessly) but the new, more powerful engines, which are set forward on the low-riding 737 and cause the nose to rise when power is applied.

        As for AF447, I’m sure this didn’t cross Boeing’s mind. The mystery there remains What caused the crew to be so confused (especially if the A330 was so perfectly good)?

  26. Tigersharktoo says:

    A couple of questions.

    Are modern jet aircraft really that close to the edge of stalling that they require automatic anti stall systems?

    Or is it just a 737 Max problem?

    Or is MCAS a solution in search of a problem?

    Why would not older stall warning systems work? What is wrong with the tried and true stick shaker?

  27. JD says:

    A few questions I’m waiting for from the investigators:

    Who was flying the plane? Was it the first officer with just 200 hours? If so did the captain take back over the control of the airplane? I just wonder how a pilot with 200 hours total is a first officer and if he received the proper training after the Lion Air crash or was he still just learning to fly period? Everyone commends the captain’s experience and training but nobody is saying the first officer was well-trained.

    Yes it was right after takeoff but how soon? More particular what was it’s altitude at the time of the issue? It could have been so low to the ground of course that even if the captain took control back (IF the first officer was flying) that there may not have been enough time to take the corrective actions to disengage the MCAS and regain control.

    Why are angle-of-attack sensors failing? Yes the MCAS is causing issues, but that software wouldn’t incorrectly override with nose-down actions if the sensors weren’t failing.

    Also I echo Ababu’s comment that Boeing has seemingly pushed the 737 too far. Maybe it’s just because I’m also a big fan of the 757, but I’d rather see Boeing improve that then try to make the 737 into a plane it’s not supposed to be.

  28. Ababu says:

    The 737 air frame is being asked to perform duties for which it is not designed. Boeing should have revived a variant of the 757, instead they cut corners and keep stretching the 737 beyond its air frame design limits with engineering gimmickry

    Reading from Wikipedia: “In November 2011, Boeing selected the larger fan diameter, necessitating a 6–8 in (150–200 mm) longer nose landing gear.[50][51] In May 2012, Boeing further enlarged the fan to 69.4 in (176 cm), paired with a smaller engine core within minor design changes before the mid-2013 final configuration.[52]

    The nacelle features chevrons for noise reduction like the 787.[53] A new bleed air digital regulator will improve its reliability.[54] The larger engine is cantilevered ahead of and slightly above the wing, and the laminar flow engine nacelle lipskin is a GKN Aerospace one-piece, spun-formed aluminum sheet inspired by the 787.[31]

    The new Maneuvering Characteristics Augmentation System accommodates the forward placement of the new engines while still retaining commonality (similar flying characteristics) with the Boeing 737NG family.”

    • Ben says:

      The point where Boeing stretched the 737 too far in length was with the 737-900 model in the late 1990s. They later came out with a mid life update to it in the 737-900ER. At the length of the 737-900/900ER along with the 737 MAX 9 and 10, it can be extremely tricky to land due to only having one bogie rear landing gear that takes the full brunt of landing forces. The similarly sized A321 and 757 have duel bogie rear landing gear that can hold more weight, and distributes landing forces over a wider area. This is where Boeing stretched the 737 too far. The 800/MAX 8 length is the longest length the 737 should have stopped at, and Boeing should have kept the 757 in production to cover that ultra stretched length.