Boeing 737 Max Software Fixes Due to Lion Air Crash Delayed
Mr O,
‘why not just disable MCAS?’
Which is part of Boeing’s proposed modification. https://www.boeing.com/commercial/73...e-updates.page
If this is so, then why is there need for training above knowledge of the system and aircraft limitations without MCAS.
‘why not just disable MCAS?’
Which is part of Boeing’s proposed modification. https://www.boeing.com/commercial/73...e-updates.page
If this is so, then why is there need for training above knowledge of the system and aircraft limitations without MCAS.
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Mr O,
‘why not just disable MCAS?’
Which is part of Boeing’s proposed modification. https://www.boeing.com/commercial/73...e-updates.page
If this is so, then why is there need for training above knowledge of the system and aircraft limitations without MCAS.
‘why not just disable MCAS?’
Which is part of Boeing’s proposed modification. https://www.boeing.com/commercial/73...e-updates.page
If this is so, then why is there need for training above knowledge of the system and aircraft limitations without MCAS.
- MCAS is needed to meet certification requirements, but it will rarely be activated, and if there is AOA disagree then MCAS will be inhibited, but the conditions under which AOA disagree occurs are only rarely encountered in the normal flight envelope.
- Boeing must test all of this, and the FAA must verify all of this, and the airlines should understand all of this, and pilots should have some knowledge and awareness of this.
- It is not necessary for each pilot to train for this on a simulator, since it is extremely unlikely to activate, and the average pilot would not actually notice the difference when MCAS activated, and would not have to take any action other than the normal control inputs.
Unless it fails in some way, which is still the elephant in the room...
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Mr O,
‘why not just disable MCAS?’
Which is part of Boeing’s proposed modification. https://www.boeing.com/commercial/73...e-updates.page
If this is so, then why is there need for training above knowledge of the system and aircraft limitations without MCAS.
‘why not just disable MCAS?’
Which is part of Boeing’s proposed modification. https://www.boeing.com/commercial/73...e-updates.page
If this is so, then why is there need for training above knowledge of the system and aircraft limitations without MCAS.
There is also the question of how well we really understand the cause of the failure; many times in my experience there another factor beyond the obvious ones. Given that there have been two additional programming (?) errors disclosed (the AOA disagree warning did not work, and some other "minor" control surface issue surfaced) it really feels like the MAX is still in beta and pilots had better be trained in all the worst case scenarios.
Boeing wants to have their cake and eat it too -- the crashes were caused by improperly trained pilots, but no more pilot training is needed! That does not make me want to fly "B" again.
Gordon, 
Water pilot, life, aviation, are probabilities.
MCAS failures must not occur in future operations - where ‘must not’ is the level of probability required for certification. This level is the internationally accepted value for equivalent safety - as low as reasonably achievable, but like all risk some small probability remains.
There is greater safety benefit in considering the wider system; thus tail trim can move to unacceptably high values - trim runaway, structural failure, … Then the important question is if pilot intervention will be able to reduce the risk; can the situation be recognised (any alerting), can the procedure be followed, is action physically possible, time available, level of knowledge / training required, … all balanced against risk - cost effectiveness.
A point can be reached where the situation is unacceptable, then the design must be changed; thence consideration of a ‘fully’ protected system, e.g. triplex FBW, but which also has a demonstrated manual backup.
It is this argument which rejects the need for specific MCAS training; although the trim runaway case probably still does. However, because the latter safety case depends pilot intervention, and with evidence from these accidents, there is the suggestion that pilot intervention is ineffective - it cannot be guaranteed.
You and others cite training - low professional standards. Alternatively, consider that the circumstances of the situation could be beyond pilot comprehension, an ambiguous emergency procedure, physically impossible to execute, … all beyond reasonable human ability. Also, if ‘reasonable’ is viewed as a probability, then this too cannot be established due ‘being human’, which even with training, cannot be sufficiently guaranteed to use in a system safety case.
Water pilot, life, aviation, are probabilities.
MCAS failures must not occur in future operations - where ‘must not’ is the level of probability required for certification. This level is the internationally accepted value for equivalent safety - as low as reasonably achievable, but like all risk some small probability remains.
There is greater safety benefit in considering the wider system; thus tail trim can move to unacceptably high values - trim runaway, structural failure, … Then the important question is if pilot intervention will be able to reduce the risk; can the situation be recognised (any alerting), can the procedure be followed, is action physically possible, time available, level of knowledge / training required, … all balanced against risk - cost effectiveness.
A point can be reached where the situation is unacceptable, then the design must be changed; thence consideration of a ‘fully’ protected system, e.g. triplex FBW, but which also has a demonstrated manual backup.
It is this argument which rejects the need for specific MCAS training; although the trim runaway case probably still does. However, because the latter safety case depends pilot intervention, and with evidence from these accidents, there is the suggestion that pilot intervention is ineffective - it cannot be guaranteed.
You and others cite training - low professional standards. Alternatively, consider that the circumstances of the situation could be beyond pilot comprehension, an ambiguous emergency procedure, physically impossible to execute, … all beyond reasonable human ability. Also, if ‘reasonable’ is viewed as a probability, then this too cannot be established due ‘being human’, which even with training, cannot be sufficiently guaranteed to use in a system safety case.
MCAS failures must not occur in future operations
MCAS does not need fixing, the data supplied to it needs to be robustly cross checked or discarded.
Technically, the MCAS software did not fail. But from an overall systems standpoint, it did. The software people may get off the hook for writing code that ran per the specification. But the spec missed an important failure mode. And was written for the wrong level of system criticality.
When I worked at Boeing, we had a number of instances where the hardware people finished their design (or were saddled with older systems for which a derivative needed to be produced given a limited budget and schedule). And once finished it got "thrown over the wall" to the software group. in part because hardware and software were (and still may be) viewed as two completely different kinds of design domains. It was up to the coders to develop something that 'worked', given the hardware peoples' attitude that remaining shortcomings could always be fixed in software.
It's a cultural problem (and not just at Boeing) that has always been way above my pay grade to fix. Even if I could see it.
When I worked at Boeing, we had a number of instances where the hardware people finished their design (or were saddled with older systems for which a derivative needed to be produced given a limited budget and schedule). And once finished it got "thrown over the wall" to the software group. in part because hardware and software were (and still may be) viewed as two completely different kinds of design domains. It was up to the coders to develop something that 'worked', given the hardware peoples' attitude that remaining shortcomings could always be fixed in software.
It's a cultural problem (and not just at Boeing) that has always been way above my pay grade to fix. Even if I could see it.
If pilots were improperly trained its absolutely nothing to do with Boeing. How can it be? They merely make aeroplanes and specify the training required to operate them safely. If a customer fails to train their pilots properly you can't blame Boeing, they had nothing to do with it.
Unless they were trained at Renton of course...
"No more training is needed for pilots who were properly trained in the first place" - does that satisfy you?
Otherwise you'd be blaming Ford for training failures in a crash when someone on the other side of the world with a photoshopped licence has gone joyriding- which is equivalent to your original statement.
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If the MAX is not flying soon
Another possible impact of the MAX grounding.GE Aviation maintains output amid Max crisis and warns of Q2 hit
- 30 April, 2019
- SOURCE: Flight Dashboard
- BY: Jon Hemmerdinger
- Boston
The grounding of the Boeing 737 Max has not yet significantly impacted the profits of engine maker GE Aviation, though General Electric’s chief executive warns of a potential financial impact in the second quarter.
Meanwhile, GE Aviation’s CFM International joint venture has continued to produce 737 Max Leap-1B engines at previous rates despite Boeing slowing its own production.
Speaking during the company’s first quarter earnings call on 30 April, GE chief executive Lawrence Culp says the grounding could affect GE Aviation equally to its CFM partner Safran Aircraft Engines.
Just days ago, Safran’s top brass warned the grounding could cost it €200 million ($224 million) in the second quarter.
“We probably have something in that same range as a headwind with respect… to our own side of the [CFM joint venture] in the second quarter,” GE’s Culp says.
The grounding “presents a new risk” he adds. “We have strong partnership with Boeing. We are confident in the 737 Max aircraft [and] we are working closely with Boeing.”
So far, GE Aviation’s production has hummed along unaffected even though in April Boeing cut 737 output by 19% to 42 aircraft monthly.
“We have not changed our engine production plan at this time, but the timing of cash flows may be impacted by collection of receivables from Boeing, depending on when aircraft deliveries resume,” says GE chief financial officer Jamie Miller.
Evendale, Ohio-based GE Aviation shipped 424 Leap engines in the first quarter, more than twice as many as in the same period of 2018. It shipped 751 commercial aviation engines of all models in the first quarter, up 15% from 651 shipments in the same period one year earlier, GE reports.
GE Aviation’s first quarter profit inched up 4% year-over-year to $1.7 billion, while revenue jumped 13% to $8.0 billion. Revenue from sales of equipment such as engines increased 24% in the quarter to $3.1 billion, while aircraft services revenue increased 4% to $4.8 billion.
The aviation unit’s first quarter profit margin slipped 1.6 percentage points year-over-year to 20.9%, GE reports. The decline primarily reflects fewer deliveries of higher-profit CFM56 engines and more deliveries of new-generation Leap engines, says Miller.
GE Aviation has been behind on Leap deliveries for months amid supply chain pressures. Earlier this year, executives said deliveries were four weeks behind schedule.
But GE Aviation has made up lost ground. It is now on schedule with Airbus and two weeks behind with Boeing, says Culp.
“We expect to be back on schedule in the second quarter,” he adds.
Meanwhile, GE Aviation’s CFM International joint venture has continued to produce 737 Max Leap-1B engines at previous rates despite Boeing slowing its own production.
Speaking during the company’s first quarter earnings call on 30 April, GE chief executive Lawrence Culp says the grounding could affect GE Aviation equally to its CFM partner Safran Aircraft Engines.
Just days ago, Safran’s top brass warned the grounding could cost it €200 million ($224 million) in the second quarter.
“We probably have something in that same range as a headwind with respect… to our own side of the [CFM joint venture] in the second quarter,” GE’s Culp says.
The grounding “presents a new risk” he adds. “We have strong partnership with Boeing. We are confident in the 737 Max aircraft [and] we are working closely with Boeing.”
So far, GE Aviation’s production has hummed along unaffected even though in April Boeing cut 737 output by 19% to 42 aircraft monthly.
“We have not changed our engine production plan at this time, but the timing of cash flows may be impacted by collection of receivables from Boeing, depending on when aircraft deliveries resume,” says GE chief financial officer Jamie Miller.
Evendale, Ohio-based GE Aviation shipped 424 Leap engines in the first quarter, more than twice as many as in the same period of 2018. It shipped 751 commercial aviation engines of all models in the first quarter, up 15% from 651 shipments in the same period one year earlier, GE reports.
GE Aviation’s first quarter profit inched up 4% year-over-year to $1.7 billion, while revenue jumped 13% to $8.0 billion. Revenue from sales of equipment such as engines increased 24% in the quarter to $3.1 billion, while aircraft services revenue increased 4% to $4.8 billion.
The aviation unit’s first quarter profit margin slipped 1.6 percentage points year-over-year to 20.9%, GE reports. The decline primarily reflects fewer deliveries of higher-profit CFM56 engines and more deliveries of new-generation Leap engines, says Miller.
GE Aviation has been behind on Leap deliveries for months amid supply chain pressures. Earlier this year, executives said deliveries were four weeks behind schedule.
But GE Aviation has made up lost ground. It is now on schedule with Airbus and two weeks behind with Boeing, says Culp.
“We expect to be back on schedule in the second quarter,” he adds.
Quote from Boeing site.
Am I just a worry wart? Boeing put in a system (MCAS) to ensure certifiable handling characteristics approaching the stall, yet crews will not receive sim training on approaches to the stall with MCAS disabled. Gotta be a gotcha there?
Flight control system will now compare inputs from both AOA sensors. If the sensors disagree by 5.5 degrees or more with the flaps retracted, MCAS will not activate. An indicator on the flight deck display will alert the pilots
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WP, that argument is completely irrational.
If pilots were improperly trained its absolutely nothing to do with Boeing. How can it be? They merely make aeroplanes and specify the training required to operate them safely. If a customer fails to train their pilots properly you can't blame Boeing, they had nothing to do with it.
Unless they were trained at Renton of course...
"No more training is needed for pilots who were properly trained in the first place" - does that satisfy you?
Otherwise you'd be blaming Ford for training failures in a crash when someone on the other side of the world with a photoshopped licence has gone joyriding- which is equivalent to your original statement.
If pilots were improperly trained its absolutely nothing to do with Boeing. How can it be? They merely make aeroplanes and specify the training required to operate them safely. If a customer fails to train their pilots properly you can't blame Boeing, they had nothing to do with it.
Unless they were trained at Renton of course...
"No more training is needed for pilots who were properly trained in the first place" - does that satisfy you?
Otherwise you'd be blaming Ford for training failures in a crash when someone on the other side of the world with a photoshopped licence has gone joyriding- which is equivalent to your original statement.
Last edited by 568; 1st May 2019 at 00:18. Reason: text
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If Ford designed a hidden system that would randomly and aggressively steer your car into the oncoming traffic, it would certainly be a problem with Ford, not the driver.
A large part of the cost will be that Boeing is the only source of the mechanics and physics of how the sim is to work. They turn $$$$ to $$$$$$$$. If they wanted to reduce the price of a sim significantly they could.
That's why the driver has a steering wheel and brakes, just in case the front end loses a single bolt
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If they have not done this work, the FAA could never certify the revised MCAS. Presumably the test details will emerge sometime soon. If not, doubt would remain about the validity of the flight envelope.
Whereas steering systems should have greater redundancy, reliability, and enable some control, even after a minor, sub system, single failure.
As should aircraft enable pitch control, and not require two people and three hands to follow a procedure.
Gordon
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During the discussions some posters mentioned LAM. One poster indicated it was present in his NG to MAX differences training. Does anyone have a short description of its design considerations, functionality, operational use, and training explanation ?
Note: This is for contextual understanding only, I am not suggesting this function had anything to do with these accidents in specific terms.
Note: This is for contextual understanding only, I am not suggesting this function had anything to do with these accidents in specific terms.
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In case anyone missed it, AvHerald posted a copy of a long list of 25 questions submitted to the FAA/FSB. Many of these touch on technical issues discussed in great detail in this thread: Crash: Ethiopian B38M near Bishoftu on Mar 10th 2019, impacted terrain after departure
For example, one of my pet issues:
For example, one of my pet issues:
10 - Did the certification consider a massive change in the function of the AoA when MCAS (as actor in the flight controls) was introduced in addition to stick shaker (monitoring only)?
In case anyone missed it, AvHerald posted a copy of a long list of 25 questions submitted to the FAA/FSB. Many of these touch on technical issues discussed in great detail in this thread: Crash: Ethiopian B38M near Bishoftu on Mar 10th 2019, impacted terrain after departure
For example, one of my pet issues:
For example, one of my pet issues:
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WP, that argument is completely irrational.
If pilots were improperly trained its absolutely nothing to do with Boeing. How can it be? They merely make aeroplanes and specify the training required to operate them safely. If a customer fails to train their pilots properly you can't blame Boeing, they had nothing to do with it.
Unless they were trained at Renton of course...
"No more training is needed for pilots who were properly trained in the first place" - does that satisfy you?
Otherwise you'd be blaming Ford for training failures in a crash when someone on the other side of the world with a photoshopped licence has gone joyriding- which is equivalent to your original statement.
If pilots were improperly trained its absolutely nothing to do with Boeing. How can it be? They merely make aeroplanes and specify the training required to operate them safely. If a customer fails to train their pilots properly you can't blame Boeing, they had nothing to do with it.
Unless they were trained at Renton of course...
"No more training is needed for pilots who were properly trained in the first place" - does that satisfy you?
Otherwise you'd be blaming Ford for training failures in a crash when someone on the other side of the world with a photoshopped licence has gone joyriding- which is equivalent to your original statement.
So you are left, as a passenger, with a rather difficult safety determination to make. I have no way of determining the skill of the pilot (if you think that ethnicity or "culture" matters, may I remind you of Colgan Air flight 3407).
Sorry if I have touched a nerve here, I am not trying to troll you. But when I board an aircraft my goal is to make it to my destination alive, and the system that I am using consists of both the plane and the pilot.
There has been no evidence presented that the pilots were in any way more deficient in training or skills than any other pilot. There has been no evidence that the seven different pilots who were fooled by this system were flying with counterfeit licenses, or that they paid off somebody to get their license, or that they were not trained. (Seven pilots because even the jump seat pilot who averted the first crash apparently had no idea why they had just saved the plane, given that they turned the power trim back on briefly after disabling it.)
On the other hand, there is evidence that the plane can sneakily point its nose towards the ground in certain very predictable failure modes (flappy things hanging on the outside of an aircraft in -40c weather do go wrong sometimes) and that the pilots are expected to notice this behavior quickly and channel their inner Wilbur Wright by turning off the newfangled electric motors and hand pulling wheels that pull cables, all the while pointing the nose of the plane at the ground and reducing airspeed. Given a choice, I would rather fly on a plane that doesn't put its pilots in that situation, or if it is proven to have done so is one where the company steps up, admits the problem, and fixes it.
Boeing's reluctance to admit that there even was a problem is a big problem in itself -- having worked for organizations that have from time to time made major boo-boos (without killing anybody that I know of) I can tell you that when the internal environment is "there really was no problem, it was all customer error and we are just going through the motions for the public's sake" then the problem will not get fixed. The guy who says "uh oh" is quickly squelched by exactly the same sort of arguments that I see here. Now I realize that a hell of a lot of money is relying on a fix, which is why I don't trust it. "Failure is not an option" never applies to engineering.
Psychophysiological entity
I hadn't read that AV item before. Frankly, I'm going to have to go back to it several times to absorb it in its entirety.
By this, I mean the not-quite-so-easy-to-understand second cut-out switch circuitry. Is this contained overview statement correct? Grief, no wonder it wasn't understood in a iPad ramble. Even after a lifetime's love of electronics, stepping on that aircraft and truly understanding the systems would be a serious challenge.
The quotes are one question, split, and in reverse order.
Again, one of the main bee-in-my-bonet's issues. Just what is the truth about that second (underfloor) column switch? I know, it's the third time I've shouted that question.
By this, I mean the not-quite-so-easy-to-understand second cut-out switch circuitry. Is this contained overview statement correct? Grief, no wonder it wasn't understood in a iPad ramble. Even after a lifetime's love of electronics, stepping on that aircraft and truly understanding the systems would be a serious challenge.
The quotes are one question, split, and in reverse order.
Again, one of the main bee-in-my-bonet's issues. Just what is the truth about that second (underfloor) column switch? I know, it's the third time I've shouted that question.
17 - On the 737 NG aircraft any autotrim can be stopped by just moving the control column in opposite direction (e.g. an autotrim nose down is stopped by a nose up control input). However, on the 737 MAX aircraft this stop has been completely disabled for MCAS to operate, hence, a trim movement can no longer be stopped by opposite control column movement causing substantial startle effects on flight crew (based on sim instructor experience).
In addition, the MCAS on MAX can not be stopped by the control column trim cut out switches, only the cut out switches at the center console, while on NG autotrim could also be permanently stopped by the cut out switches at the control column without disabling manual electric trim on NG aircraft. Would the FAA not agree, that this is a very significant difference between the aircraft, that could cause a crew to lose control in time critical stages of flight? Was this risk assessed during certification of the MAX systems?