Ethiopian airliner down in Africa
They did not. Please read how MCAS functions particularly the limits on how far it can move the stab in each cycle. I guess what most of the posters are saying is that pilots no longer need to be pilots.
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Amazed spinning that trimwheel about like that ever passed muster at Boeing let alone nodded through by AW @ FAA - a dozen things could be predicted to go wrong day one of concept by a brainstorming group of experienced systems and aeronautic engineers.
Pilots still need to be pilots. They still need to be able to expect and adapt for the unexpected, and not Children of the Magenta Line.
However it's not unexpected anymore, the bandaid of MCAS on an old aircraft was designed and approved by Engineers of the Financial line.
However it's not unexpected anymore, the bandaid of MCAS on an old aircraft was designed and approved by Engineers of the Financial line.
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Pilots still need to be pilots. They still need to be able to expect and adapt for the unexpected, and not Children of the Magenta Line.
However it's not unexpected anymore, the bandaid of MCAS on an old aircraft was designed and approved by Engineers of the Financial line.
However it's not unexpected anymore, the bandaid of MCAS on an old aircraft was designed and approved by Engineers of the Financial line.
Perhaps those questioning the age and hours of pilots might also, or mire profitably, question that of design engineers and AW 'professionals' - certainly of those in decision making rôles ?
Last edited by HarryMann; 17th Mar 2019 at 13:46.
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Read all that. Stab screw found pointed down. Are you suggesting pilots pushed it that way? Right. So furthermore they couldn't pull it back in time. Not a good system then right?
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Totally agree with that but where were those people. In fact how did it get approved by Boeing. Perhaps since it was supposed to be an "augmentation" system?
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From the New York Times, an article titled, After 2 Crashes of New Boeing Jet, Pilot Training Now a Focus, March 16, 2019:
https://www.nytimes.com/2019/03/16/business/boeing-max-flight-simulator-ethiopia-lion-air.html?emc=edit_nn_20190317&nl=morning-briefing&nlid=4764506920190317&te=1
A version of this article appears in print on March 17, 2019, on Page A1 of the New York edition with the headline: Left Little Time for Pilot Training.
The chief executive of Boeing backed down on Wednesday. He called President Trump to recommend that the United States temporarily take the company’s best-selling jet out of service, following two deadly crashes in less than five months. Hours later, the president announced that the plane had been grounded.
It was a stark reversal for Boeing, an industrial juggernaut that has enjoyed a decade of rapid growth and has deep ties in Washington. Just the day before, the chief executive, Dennis A. Muilenburg, had urged the president to keep the plane flying, as regulators around the world banned the jet.
It was a stark reversal for Boeing, an industrial juggernaut that has enjoyed a decade of rapid growth and has deep ties in Washington. Just the day before, the chief executive, Dennis A. Muilenburg, had urged the president to keep the plane flying, as regulators around the world banned the jet.
A version of this article appears in print on March 17, 2019, on Page A1 of the New York edition with the headline: Left Little Time for Pilot Training.
Last edited by airman1900; 17th Mar 2019 at 13:55. Reason: Added second paragraph of article
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Pilots still need to be pilots. They still need to be able to expect and adapt for the unexpected, and not Children of the Magenta Line.
However it's not unexpected anymore, the bandaid of MCAS on an old aircraft was designed and approved by Engineers of the Financial line.
However it's not unexpected anymore, the bandaid of MCAS on an old aircraft was designed and approved by Engineers of the Financial line.
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Test pilots approval
Whether or not MCAS played a part in the Ethiopian crash and to what extent it did in the Lion Air, I am puzzled how a lot of posters here blame the engineering community. From what I remember from working for an aircraft manufacturer only a few years back, the design decision making process for systems relating to flight control thoroughly involved the test engineers and test pilots, who can't be blamed for lacking aviation culture.
If the design is at fault, then the whole 'system' from management, engineering, test pilots and certification authorities played a part in aligning the holes of this Swiss cheese.
If the design is at fault, then the whole 'system' from management, engineering, test pilots and certification authorities played a part in aligning the holes of this Swiss cheese.
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Hello Slip and Turn!
May I postulate a speculation? You raise a good point that perhaps MCAS might be a bit of a red herring, that perhaps all was not right even before rotation. The behavior of the flights that crashed did not seem 'normal' very soon after takeoff. It has occurred to me that the 737 Max and its immediate predecessor are not the same airframe: is it possible that the 'microenvironment' (aerodynamically speaking) around and near the AOA sensors could be significantly different at similar points in the flight envelope. The giant engines and their nacelles (placed forward of it's predecessors) might possibly result in erroneous interpretations of AOA and airspeed secondary to different airflow patterns vs those of the immediate predecessor to the 737 Max. This microenvironment of airflow might not have been explicitly modelled or tested in the test regime. Just my two cents. Part of my work knowledge (in Anesthesiology and Critical Care) centers around constant troubleshooting of what our biomedical sensors are telling us: is it accurate data or is it compromised somehow by the microenvironment, kinks in pressure tubing, etc. Just a lowly PPL myself, but I always envision the takeoff roll and the time around and after rotation as a very dynamic situation. Putting a new, giant and powerful engine (in a different place) on a 50 year old frame might induce novel anomalies to the sensors.
May I postulate a speculation? You raise a good point that perhaps MCAS might be a bit of a red herring, that perhaps all was not right even before rotation. The behavior of the flights that crashed did not seem 'normal' very soon after takeoff. It has occurred to me that the 737 Max and its immediate predecessor are not the same airframe: is it possible that the 'microenvironment' (aerodynamically speaking) around and near the AOA sensors could be significantly different at similar points in the flight envelope. The giant engines and their nacelles (placed forward of it's predecessors) might possibly result in erroneous interpretations of AOA and airspeed secondary to different airflow patterns vs those of the immediate predecessor to the 737 Max. This microenvironment of airflow might not have been explicitly modelled or tested in the test regime. Just my two cents. Part of my work knowledge (in Anesthesiology and Critical Care) centers around constant troubleshooting of what our biomedical sensors are telling us: is it accurate data or is it compromised somehow by the microenvironment, kinks in pressure tubing, etc. Just a lowly PPL myself, but I always envision the takeoff roll and the time around and after rotation as a very dynamic situation. Putting a new, giant and powerful engine (in a different place) on a 50 year old frame might induce novel anomalies to the sensors.
So, there was Qantas with an A380, where the assumed failure modes of certification didn't bear much resemblance with the real world. There was also Qantas' A330 FBW going nuts, and the B744 where the O2 bottle went cross country out the side of the plane. There was UAL 811, which didn't bear much resemblance with simulator sessions, Alaskan 261, UAL232, BA037, and the hudson ferry....
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.
- Hamlet (1.5.167-8), Hamlet to Horatio
On the other hand, we have AF447... Adam Air, and a panoply of headlines of crew being outside the loop. Every day, crew deal with oddities with the aircraft, that come to light where reality meets assumptions and a gap exists. The majority of occasions do not end up in headlines, the crews just get on with the task, write up the events and go home and take crew rest. Occasionally, that doesn't work out, and we have bad days. The direction of air transport has added distance between the operator and the aircraft, through design and perceived safety benefits of reliance on automation. That is a high stakes assumption and it is routinely shown to be invalid. Consider AZ214 and similar bad days. Automation is great, but it is only great if it is working as expected, and where the monitoring is not degraded by the out of loop condition, or the degradation and or inertia that develops to the operator intervening with a system. All RPT aircraft fly like Cessnas and Pipers at the basic level, yet we have flight crew that are reticent to intervene and take control of the aircraft when wacky stuff starts. The reticence is a paradoxical response to the focus on compliance, reporting and rigid management directives to reliance on automation to reduce errors.
We can't design a reliable toaster, yet the assumption is made that an engineer 30 years ago can predict the conditions of weather, fuel state, fuel policy, system malfunctions, traffic, ATC capability, and crew training etc, such that errors cannot occur. We can't make windows or iPhones work without error, the system couldn't imagine foam bringing down a spacecraft, or cold temperatures mussing with sealing of an O ring... Passengers hop on an aircraft in country A, and fly for a day and night to country B, and land in weather that you won't drive your car in. The crews do that every day, and thousands of times, in ice storms, weather fronts, fog and sometimes sunny calm days. They do it with controlled aircraft flying in proximity to other aircraft that are not controlled, and hopefully the 15 hour student doesn't mess up, and enter the airspace that the punters are spending time in a tube complaining about the peanuts, coke and pretzels that are part and parcel of unregulated air travel. When we can build reliable toasters, then the necessity for human competency to be maintained may be mitigated, maybe.
The balance of reinforcement training is hard to get right, back in the late 90's there was a push to make crew more aware of handling of aircraft, and that led in passing to AA587. A little knowledge can be a dangerous thing. Getting the mix right is not easy, but we certainly do not have it at this time, and have not for many years. This is not generational, it is institutional. Last time I looked, the world was not flat, supported by turtles all the way down, it is a weird oblate spheroid and strange stuff happens that takes care to avoid having bad days, that care takes SA, and knowledge and skills to respond to the information that is provided to the crew. We have a problem in getting the loop right all of the time. 10^-9 reliability is fantastic, except for the poor pax that are the statistic. [yeah, -6 is the basic level, but the events we see that get into the headlines are much more remote than that]
PS: links in chains presume a simple model of the world; a chain is a linear analogue, and the world flat or oblate spheroid, is much more entertaining. When you place a band aid onto a cut, you have introduced new failure modes and vectors for badnesses, directly and indirectly. Have a fuel fright on one flight, add more, and have an aircraft roll off the end of the runway, Too many unstabilised approaches? demand AP/FD use form minimum engagement, and then wonder why the crew ding pods and tails, or ham fist AP faults. The world is stochastic, non linear, and every barrier that gets put up acts as much as a new surface to bounce issues off in new directions as it acts as a barrier. This is not a pessimistic view of the world, it is one that SMS programs (ICAO DOC 9859 etc) and audit processes need to be comprehended in their constraints and limitations. Functional resonance is a reality and that suggests the key to safe management is comprehensive awareness of the interaction of policy, procedures and practices with the real world.
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.
- Hamlet (1.5.167-8), Hamlet to Horatio
On the other hand, we have AF447... Adam Air, and a panoply of headlines of crew being outside the loop. Every day, crew deal with oddities with the aircraft, that come to light where reality meets assumptions and a gap exists. The majority of occasions do not end up in headlines, the crews just get on with the task, write up the events and go home and take crew rest. Occasionally, that doesn't work out, and we have bad days. The direction of air transport has added distance between the operator and the aircraft, through design and perceived safety benefits of reliance on automation. That is a high stakes assumption and it is routinely shown to be invalid. Consider AZ214 and similar bad days. Automation is great, but it is only great if it is working as expected, and where the monitoring is not degraded by the out of loop condition, or the degradation and or inertia that develops to the operator intervening with a system. All RPT aircraft fly like Cessnas and Pipers at the basic level, yet we have flight crew that are reticent to intervene and take control of the aircraft when wacky stuff starts. The reticence is a paradoxical response to the focus on compliance, reporting and rigid management directives to reliance on automation to reduce errors.
We can't design a reliable toaster, yet the assumption is made that an engineer 30 years ago can predict the conditions of weather, fuel state, fuel policy, system malfunctions, traffic, ATC capability, and crew training etc, such that errors cannot occur. We can't make windows or iPhones work without error, the system couldn't imagine foam bringing down a spacecraft, or cold temperatures mussing with sealing of an O ring... Passengers hop on an aircraft in country A, and fly for a day and night to country B, and land in weather that you won't drive your car in. The crews do that every day, and thousands of times, in ice storms, weather fronts, fog and sometimes sunny calm days. They do it with controlled aircraft flying in proximity to other aircraft that are not controlled, and hopefully the 15 hour student doesn't mess up, and enter the airspace that the punters are spending time in a tube complaining about the peanuts, coke and pretzels that are part and parcel of unregulated air travel. When we can build reliable toasters, then the necessity for human competency to be maintained may be mitigated, maybe.
The balance of reinforcement training is hard to get right, back in the late 90's there was a push to make crew more aware of handling of aircraft, and that led in passing to AA587. A little knowledge can be a dangerous thing. Getting the mix right is not easy, but we certainly do not have it at this time, and have not for many years. This is not generational, it is institutional. Last time I looked, the world was not flat, supported by turtles all the way down, it is a weird oblate spheroid and strange stuff happens that takes care to avoid having bad days, that care takes SA, and knowledge and skills to respond to the information that is provided to the crew. We have a problem in getting the loop right all of the time. 10^-9 reliability is fantastic, except for the poor pax that are the statistic. [yeah, -6 is the basic level, but the events we see that get into the headlines are much more remote than that]
PS: links in chains presume a simple model of the world; a chain is a linear analogue, and the world flat or oblate spheroid, is much more entertaining. When you place a band aid onto a cut, you have introduced new failure modes and vectors for badnesses, directly and indirectly. Have a fuel fright on one flight, add more, and have an aircraft roll off the end of the runway, Too many unstabilised approaches? demand AP/FD use form minimum engagement, and then wonder why the crew ding pods and tails, or ham fist AP faults. The world is stochastic, non linear, and every barrier that gets put up acts as much as a new surface to bounce issues off in new directions as it acts as a barrier. This is not a pessimistic view of the world, it is one that SMS programs (ICAO DOC 9859 etc) and audit processes need to be comprehended in their constraints and limitations. Functional resonance is a reality and that suggests the key to safe management is comprehensive awareness of the interaction of policy, procedures and practices with the real world.
Very well written and well worth everyone to read . JMO with over 26k hours in the 737.
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Light aircraft pilot since the mid 70s... under what circumstances would a 737 variant require full UP trim or full DOWN trim? On the aircraft that I have flown, the trim spends all its time somewhere in the middle of the range. So again I ask, what purpose is there to having such extreme ranges of trim that it requires huge control forces to counter?
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I hope Boeing takes a long look at the control system theory on MCAS which uses the long time constant of a lead screw in the feedback loop before they just supply a software patch. It is surprising they would use such a slow responsive element in the dynamic stall situation just to add stick feel.
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Seattle Times article
Flawed analysis, failed oversight: How Boeing and FAA certified the suspect 737 MAX flight control system
Current and former engineers directly involved with the evaluations or familiar with the document shared details of Boeing’s “System Safety Analysis” of MCAS, which The Seattle Times confirmed.
The safety analysis:
The safety analysis:
- Understated the power of the new flight control system, which was designed to swivel the horizontal tail to push the nose of the plane down to avert a stall. When the planes later entered service, MCAS was capable of moving the tail more than four times farther than was stated in the initial safety analysis document.
- Failed to account for how the system could reset itself each time a pilot responded, thereby missing the potential impact of the system repeatedly pushing the airplane’s nose downward.
- Assessed a failure of the system as one level below “catastrophic.” But even that “hazardous” danger level should have precluded activation of the system based on input from a single sensor — and yet that’s how it was designed.
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Hello Slip and Turn!
May I postulate a speculation? You raise a good point that perhaps MCAS might be a bit of a red herring, that perhaps all was not right even before rotation. The behavior of the flights that crashed did not seem 'normal' very soon after takeoff. It has occurred to me that the 737 Max and its immediate predecessor are not the same airframe: is it possible that the 'microenvironment' (aerodynamically speaking) around and near the AOA sensors could be significantly different at similar points in the flight envelope. The giant engines and their nacelles (placed forward of it's predecessors) might possibly result in erroneous interpretations of AOA and airspeed secondary to different airflow patterns vs those of the immediate predecessor to the 737 Max. This microenvironment of airflow might not have been explicitly modelled or tested in the test regime. Just my two cents. Part of my work knowledge (in Anesthesiology and Critical Care) centers around constant troubleshooting of what our biomedical sensors are telling us: is it accurate data or is it compromised somehow by the microenvironment, kinks in pressure tubing, etc. Just a lowly PPL myself, but I always envision the takeoff roll and the time around and after rotation as a very dynamic situation. Putting a new, giant and powerful engine (in a different place) on a 50 year old frame might induce novel anomalies to the sensors.
May I postulate a speculation? You raise a good point that perhaps MCAS might be a bit of a red herring, that perhaps all was not right even before rotation. The behavior of the flights that crashed did not seem 'normal' very soon after takeoff. It has occurred to me that the 737 Max and its immediate predecessor are not the same airframe: is it possible that the 'microenvironment' (aerodynamically speaking) around and near the AOA sensors could be significantly different at similar points in the flight envelope. The giant engines and their nacelles (placed forward of it's predecessors) might possibly result in erroneous interpretations of AOA and airspeed secondary to different airflow patterns vs those of the immediate predecessor to the 737 Max. This microenvironment of airflow might not have been explicitly modelled or tested in the test regime. Just my two cents. Part of my work knowledge (in Anesthesiology and Critical Care) centers around constant troubleshooting of what our biomedical sensors are telling us: is it accurate data or is it compromised somehow by the microenvironment, kinks in pressure tubing, etc. Just a lowly PPL myself, but I always envision the takeoff roll and the time around and after rotation as a very dynamic situation. Putting a new, giant and powerful engine (in a different place) on a 50 year old frame might induce novel anomalies to the sensors.
other malfunctions peculiar to these errant flights, yes, maybe.
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Quite agree but I'll ask you a question;
Is any fix to MCAS sufficient for crews that fly the aircraft to be comfortable in the safety of the type or will there still be some crew who have a little voice in the back of their heads saying 'oh s**t, a Max on this leg (and I do not refer to capability of crew, but workload of maybe a tired crew on their last leg of the day with just another pay attention to jolt)?
Salute!
Thank you, Zeffy
Another layer of the oinion has been peeled back
I, too, questioned the amount of trim movement as well as the repetitive sequence if the pilot beeped his trim switch.
Two and a half degrees of AoA on the big stab seems to be a lot. And then to keep doing it without some indication other than another nose down trim that you have not needed nor commanded.?
I fully understand that if the AoA is FUBAR, then MCAS will keep up its act until AoA is within limits or the crew disables electric trim. I got it, I read all the instructions before I flew the next time, as I didn't know we had the system until my buddy crashed the other day..
Covered our procedure to beat Hal during preflight briefing, and Joe Baggadonuts thot it was a good idea because he didn't know about MCAS either. Besides, he weighs fifty pounds more than me and is built like NFL linebacker. So if it looked like MCAS was on a binge, then he could pull back and I would turn off the electric trim. So there!
Let's roll...
Gums sends...
Thank you, Zeffy
Another layer of the oinion has been peeled back
I, too, questioned the amount of trim movement as well as the repetitive sequence if the pilot beeped his trim switch.
Two and a half degrees of AoA on the big stab seems to be a lot. And then to keep doing it without some indication other than another nose down trim that you have not needed nor commanded.?
I fully understand that if the AoA is FUBAR, then MCAS will keep up its act until AoA is within limits or the crew disables electric trim. I got it, I read all the instructions before I flew the next time, as I didn't know we had the system until my buddy crashed the other day..
Covered our procedure to beat Hal during preflight briefing, and Joe Baggadonuts thot it was a good idea because he didn't know about MCAS either. Besides, he weighs fifty pounds more than me and is built like NFL linebacker. So if it looked like MCAS was on a binge, then he could pull back and I would turn off the electric trim. So there!
Let's roll...
Gums sends...
Last edited by gums; 17th Mar 2019 at 15:40. Reason: grammar, clarification
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Thank you Harry I appreciate that! In the back of my mind it seemed very unlikely that such an anomaly (radically changed airflow patterns secondary to larger engines mounted in forward positions) would slip through aerodynamic modelling and windtunnel testing etc unnoticed. It was naive for me to assume that the designers simply specified a big change in engine fitment without anticipating the consequences.