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Ethiopian Airways flight crashes (10/03) + 737 MAX grounding

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Bald Rick

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In the news tody, it looks like Boeing will be hit with enormous leasing and additional fuel costs caused by their grounding the entire fleet of 737 MAXs.

Not to mention lawsuits, the first of which has been filed in a US Federal court. I should think the insurers will be looking at their schedules as well.
 
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Shaw S Hunter

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The bottom line is that the Boeing 737 has at its heart a basic architecture that is over 50 years old in particular being designed to sit relatively low to the ground. As such it's ill-suited to the large diameter high-bypass turbofan engines necessary for fuel economy today. My suspicion is that the only way to save the MAX is to accept that it has to be certified as a new model completely separate from the previous 737 iterations. This will certainly increase training costs for airlines but without that change the MAX may have no future at all.
 

WatcherZero

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Yeah talk is that FAA will recertify it within a couple of weeks but the European and Canadian regulators are likely to insist on a separate certification programme of the software with themselves and refuse to recognise the FAA certification because they don't trust it.
 

AM9

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Yeah talk is that FAA will recertify it within a couple of weeks but the European and Canadian regulators are likely to insist on a separate certification programme of the software with themselves and refuse to recognise the FAA certification because they don't trust it.
And that refusal by Canada and European countires will trigger an avalanche of similar reactions from Australasia, the Far East, and of course, Ethopia.
 

Western Lord

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The bottom line is that the Boeing 737 has at its heart a basic architecture that is over 50 years old in particular being designed to sit relatively low to the ground. As such it's ill-suited to the large diameter high-bypass turbofan engines necessary for fuel economy today. My suspicion is that the only way to save the MAX is to accept that it has to be certified as a new model completely separate from the previous 737 iterations. This will certainly increase training costs for airlines but without that change the MAX may have no future at all.
The 737 Max cannot be certificated as a new model because the 737 design does not meet current certification requirements in some areas, they rely on "grandfather rights" to get it a ticket. The whole point with the Max was that pilots would require minimal training and it would have a common type rating with the previous NG models. At the very least, I would imagine that the common type rating would not be accepted by airworthiness authorities, at least outside the USA.
 

Shaw S Hunter

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The 737 Max cannot be certificated as a new model because the 737 design does not meet current certification requirements in some areas, they rely on "grandfather rights" to get it a ticket. The whole point with the Max was that pilots would require minimal training and it would have a common type rating with the previous NG models. At the very least, I would imagine that the common type rating would not be accepted by airworthiness authorities, at least outside the USA.

If the basic 737 design does not meet current certification requirements then it would not be flying! The grandfather rights refers to pilot certification rather than the airframe. If your statement was to be taken as valid then there would be more than just the MAX fleet grounded. The current issue is all about MCAS being necessary to allow the common type rating for pilots: not in any way a bad thing in itself but the implementation appears to have been thoroughly botched by Boeing while the admittedly underfunded FAA has been asleep on the job.
 

Greybeard33

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Aircraft do have "grandfather rights". Amendments to airworthiness regulations do not normally apply retrospectively to aircraft types that are already certificated. When there is a major modification to an aircraft type, the airworthiness authorities may require compliance with the latest amendments in the areas of change, but the extent of these is open to interpretation.

The FAA has traditionally been more lenient with domestic US manufacturers than when certifying foreign aircraft. The 737 originally received its type certificate in the 1960s and all subsequent variants have been certificated as new models of the same aircraft type. Much of the MAX structure and systems design was deemed to be essentially unchanged from the original 737-100 and so is certificated against the airworthiness regulations as they were in the 1960s, not any subsequent amendments.
 

WatcherZero

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He means that the 737 MAX wouldn't pass certification as a brand new aircraft today, and it hasn't. Its been type-certified as a subtype of the 737 with only the changed components (15% of the aircraft) recertified along with 2000 flying hours and ETOPS certification.
 

Peter Mugridge

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Is that 15% changed against the most recent previous variation rather than 15% changed against the -100...?
 

Peter Mugridge

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That being the case... I have to ask the supplementary question, what is the percentage difference changed since the -100?

I suspect it'll be a very high percentage and it will graphically underline the point discussed in the last page or two?
 

TheEdge

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That being the case... I have to ask the supplementary question, what is the percentage difference changed since the -100?

I suspect it'll be a very high percentage and it will graphically underline the point discussed in the last page or two?

Looking at the very basic specs on Wikipedia it looks like the only measurement common between the 737-100 and the MAX is the width of the fuselage and cabin.
 

Western Lord

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Looking at the very basic specs on Wikipedia it looks like the only measurement common between the 737-100 and the MAX is the width of the fuselage and cabin.
The basic fuselage architecture is the same and indeed the upper lobe dates back to the Boeing 707 (the cockpit window design is the same). The only external change has been the elimination of the cockpit "eyebrow" windows in recent years. The use of fundamentally the same fuselage design is one of the problems that Boeing have had in that the centre section cannot accommodate a longer landing gear which would provide the much needed greater ground clearance for bigger engines. Instead Boeing has had to install the engines further forward and higher with associated undesirable aerodynamic effects which the trick software is supposed to counter. I believe that one of the areas that grandfather rights applies to is that the doors on this basically 1950's fuselage design do not meet current standards.
 

Bletchleyite

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The basic fuselage architecture is the same and indeed the upper lobe dates back to the Boeing 707 (the cockpit window design is the same). The only external change has been the elimination of the cockpit "eyebrow" windows in recent years. The use of fundamentally the same fuselage design is one of the problems that Boeing have had in that the centre section cannot accommodate a longer landing gear which would provide the much needed greater ground clearance for bigger engines. Instead Boeing has had to install the engines further forward and higher with associated undesirable aerodynamic effects which the trick software is supposed to counter. I believe that one of the areas that grandfather rights applies to is that the doors on this basically 1950's fuselage design do not meet current standards.

The IT system is more remarkable in basically being a bodge to avoid a problem. I'd have less of an issue with it were it a full Airbus-style fly by wire system with the safeguards and consistency that provides (not that it's perfect). After all the Eurofighter is allegedly incredibly difficult or impossible to fly manually due to "relaxed stability" - but with a full fly-by-wire system that isn't an issue.

But would that be too big a change to grandfather, I guess?

I think the 737 must now have reached its ultimate "bodge another bit of ally on" end, and a new aircraft (possibly based on the composite 787 fuselage) should be developed. Not only would there be safety benefits but also passenger comfort ones like the lower cabin altitude, the large windows and the higher moisture level - with those, they'd have a big advantage over Airbus.
 

WatcherZero

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Eurofighter is intentionally aerodynamically unstable to increase manoeuvring performance, namely banking speed. Similar computer control required aircraft, though in their case simply having the aerodynamics of a brick are the B2 and F117.
 

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Eurofighter is intentionally aerodynamically unstable to increase manoeuvring performance, namely banking speed. Similar computer control required aircraft, though in their case simply having the aerodynamics of a brick are the B2 and F117.
Yes, the typhoon is based on an unstable deisgn with very agile flight characteristics mainly using the canard wings. The on board automation provides a stable platform and the pilot then flies the aircraft with very fast acting control actions. The automation is based on four computers, each to different designs running different software to minimise common mode failures. In the even of a dispute a 'poll' is taken to create the 'least risky' action.
 

TheEdge

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While the intentional instability of the Typhoon is interesting and the requirement of complex software is understandable its somewhat a distraction.

Flying above Syria dodging SAMs is different to flying 180 sweaty British tourists back from Mallorca. One of those no doubt needs those computers and software to keep the aircraft even close to flyable, the other should not require such a significant, the term can only be bodge job, to keep it in the air!
 

AM9

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While the intentional instability of the Typhoon is interesting and the requirement of complex software is understandable its somewhat a distraction.

Flying above Syria dodging SAMs is different to flying 180 sweaty British tourists back from Mallorca. One of those no doubt needs those computers and software to keep the aircraft even close to flyable, the other should not require such a significant, the term can only be bodge job, to keep it in the air!
It's not a distraction at all. Many systems embodied in modern civil aircraft are inherited from military advances. The point that I was making is that it's OK creating an agile (or economical, stable, low landing-speed etc.) airframe design, but it can't be done on the cheap. The capabilities of even the best prepared pilots may be inadequate to maintain control of some modern aircraft's entire flight envelopes, thereby making computer assistance essential. That assistance must be more reliable than a simple bolt-on device that is vulnerable to simple sensor misbehaviour, - it has been available for some time but in some companies a 'let's save money at all costs' attitude encourages a cavalier attitude to system safety to prevail. Add that to a lax, nationalistic bias culture in the government department whose prime responsibility is to police such practices and we have a toxic safety environment.
 

edwin_m

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It's not a distraction at all. Many systems embodied in modern civil aircraft are inherited from military advances. The point that I was making is that it's OK creating an agile (or economical, stable, low landing-speed etc.) airframe design, but it can't be done on the cheap. The capabilities of even the best prepared pilots may be inadequate to maintain control of some modern aircraft's entire flight envelopes, thereby making computer assistance essential. That assistance must be more reliable than a simple bolt-on device that is vulnerable to simple sensor misbehaviour, - it has been available for some time but in some companies a 'let's save money at all costs' attitude encourages a cavalier attitude to system safety to prevail. Add that to a lax, nationalistic bias culture in the government department whose prime responsibility is to police such practices and we have a toxic safety environment.
I think that point was made in the sense that inherent instability has some benefits for a military aircraft but none for an airliner. Or if there are any they aren't worth the bother of proving the necessary software to be safe and maintaining public confidence when someone "reveals" that if the computer fails the plane will instantly drop out of the sky.

I wonder if the root of this issue is that the 737 is inherently a 50-year-old design that was simple and reliable when first introduced but has now had so many features bolted on (including semi-fly-by-wire features like MCAS) that nobody really understands the whole picture. Grandfathering gets extremely tricky when the operating environment changes, which might reveal unexpected hazards in things that worked fine previously, and once the grandfathers have retired it may not be easy to work out what the rationale was for a particular design decision. Whereas the A320 series was designed from the ground up as a fly-by-wire aircraft so may have more consistency around it - though I guess even that has evolved quite a bit too.
 

TheEdge

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I think that point was made in the sense that inherent instability has some benefits for a military aircraft but none for an airliner. Or if there are any they aren't worth the bother of proving the necessary software to be safe and maintaining public confidence when someone "reveals" that if the computer fails the plane will instantly drop out of the sky.

I wonder if the root of this issue is that the 737 is inherently a 50-year-old design that was simple and reliable when first introduced but has now had so many features bolted on (including semi-fly-by-wire features like MCAS) that nobody really understands the whole picture. Grandfathering gets extremely tricky when the operating environment changes, which might reveal unexpected hazards in things that worked fine previously, and once the grandfathers have retired it may not be easy to work out what the rationale was for a particular design decision. Whereas the A320 series was designed from the ground up as a fly-by-wire aircraft so may have more consistency around it - though I guess even that has evolved quite a bit too.

That was more my point, what might be acceptable to a Eurofighter shouldn't really be necessary for an airliner.

I'm not aware if Boeing intended to end the 737 line with the MAX but I suspect their hand may be forced now. Although I'd be shocked if there wasn't a design based on the tech in the 787 for a new narrowbody in some stage of development.
 

LOL The Irony

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That was more my point, what might be acceptable to a Eurofighter shouldn't really be necessary for an airliner.

I'm not aware if Boeing intended to end the 737 line with the MAX but I suspect their hand may be forced now. Although I'd be shocked if there wasn't a design based on the tech in the 787 for a new narrowbody in some stage of development.
I also believe the same. It's basic design is 65 years old in May. I think it's time for a replacement.
 

AM9

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I think that point was made in the sense that inherent instability has some benefits for a military aircraft but none for an airliner. Or if there are any they aren't worth the bother of proving the necessary software to be safe and maintaining public confidence when someone "reveals" that if the computer fails the plane will instantly drop out of the sky.

But that issue has already been dealt with in the case of fly-by-wire. When the A320 was launched, it wasn't just fly-by-wire as in the levers/cables/hydraulic links were swapped for transducers on the end of electrical wires. In order to allow those controls to operate, their effects had to be limited within the overall flight envelope in ways that looked at all of the controls available to the pilot, so contradicting settings were unlikely to create conditions outside the envelope. There were computers already in place to ensure that. Until that time, the function was largely under the control of the pilot as a mechanical set of comprehensive interlocks would be both unacceptably heavy and probably unreliable. The unfortunate incident of AF296 could have delayed the introduction of FBW for a long time had there been a sustained belief that the electronics was the cause of the actual envelope and grounding. Whether the ongoing conspiracies were correct or not, the aircraft series has been seen as a FBW success over the long-term.

I wonder if the root of this issue is that the 737 is inherently a 50-year-old design that was simple and reliable when first introduced but has now had so many features bolted on (including semi-fly-by-wire features like MCAS) that nobody really understands the whole picture. Grandfathering gets extremely tricky when the operating environment changes, which might reveal unexpected hazards in things that worked fine previously, and once the grandfathers have retired it may not be easy to work out what the rationale was for a particular design decision. Whereas the A320 series was designed from the ground up as a fly-by-wire aircraft so may have more consistency around it - though I guess even that has evolved quite a bit too.

I believe that he root of the issue with the 737 MAX is the commercial imperative that brushes away any attempts to qualify safety critical developments in designs in a responsible manner if it might affect profits, and it seems that the FAA are also complicit in this. A responsible design authority would scope design qualification to verify the integrity of the new system, i.e. the aircraft.* Boeing are now paying the price of any such behaviour with severe reputational damage, and all that follows that. As for the FAA, who knows where that will go, - a name change?
* Hence my parallel with Grenfell. It's a cultural issue with criminal consequences.
 

robk23oxf

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Boeing did start preliminary design work on a new single-aisle aircraft in the middle of the last decade but abandoned those plans a bit later on. It will be interesting to see what happens in this highly competitive section of the market now; Boeing may well be forced into going for a clean-sheet design in the next decade and it may be able to use the composite technology from the 787. This would certainly give Boeing an advantage over Airbus in terms of efficiency and so Airbus may also be forced to consider their own composite single-aisle airliner.

Boeing and Airbus tend to react to each other; Airbus launched the A350XWB in response to the 787 while Boeing reacted to the A320neo with the 737 MAX. If the 737 has indeed reached it's design limit then the next decade could be very interesting.
 

WatcherZero

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The latest is Boeing have pulled their software ‘fix’ from FAA approval this week and said it will take several weeks longer than expected to fix. The fix was supposedly making the disagree light standard, using data from both sensors rather than just one, limiting MCAS to make 25% of maximimum trim rather than 100% and turning MCAS off if the sensors disagreed.

The issue theyve likely encountered now is the instability MCAS was meant to tackle is no longer fully mitigated and the plane no longer handles like an earlier 737.
 

TheEdge

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The latest is Boeing have pulled their software ‘fix’ from FAA approval this week and said it will take several weeks longer than expected to fix. The fix was supposedly making the disagree light standard, using data from both sensors rather than just one, limiting MCAS to make 25% of maximimum trim rather than 100% and turning MCAS off if the sensors disagreed.

The issue theyve likely encountered now is the instability MCAS was meant to tackle is no longer fully mitigated and the plane no longer handles like an earlier 737.

Thinking hypothetically now what will happen if it turns out it will be impossible to get the MAX family flying under the same type rating as the rest of the 737s?

Are the airlines that have all placed no doubt multi million and billion dollar orders going to cancel them? Are they likely to demand their orders be filled with 737NGs instead? For airlines like Southwest and Ryanair where 100% fleet commonality is a cornerstone of the business model AND have massive orders what are they likely to do?
 

Greybeard33

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Thinking hypothetically now what will happen if it turns out it will be impossible to get the MAX family flying under the same type rating as the rest of the 737s?

Are the airlines that have all placed no doubt multi million and billion dollar orders going to cancel them? Are they likely to demand their orders be filled with 737NGs instead? For airlines like Southwest and Ryanair where 100% fleet commonality is a cornerstone of the business model AND have massive orders what are they likely to do?
Absent the common type rating, airlines with both the NG and the MAX in their fleet would have three options:
  1. Divide their pilots into separate pools, one for the NG and one for the MAX
  2. Organise pilot rosters so that everyone flies both models sufficiently frequently to keep both type ratings current
  3. Provide refresher courses to keep pilots current on the model they do not fly regularly.
Or some combination of the above.

This would likely increase operational costs, which would put Boeing at a competitive disadvantage. All models of the Airbus A320 family have a common type rating.
 

Shaw S Hunter

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Thinking hypothetically now what will happen if it turns out it will be impossible to get the MAX family flying under the same type rating as the rest of the 737s?

Are the airlines that have all placed no doubt multi million and billion dollar orders going to cancel them? Are they likely to demand their orders be filled with 737NGs instead? For airlines like Southwest and Ryanair where 100% fleet commonality is a cornerstone of the business model AND have massive orders what are they likely to do?

The MAX was launched in response to Airbus' NEO (= New Engine Option). The difference in fuel efficiency is such that Boeing had little choice but to make that response. ISTM highly unlikely that airlines would be prepared to convert MAX orders for NGs. Though it is also worth pointing out that Airbus has just as big a backlog of orders as Boeing so cancelling MAXs in favour of NEOs is not really a solution.

Absent the common type rating, airlines with both the NG and the MAX in their fleet would have three options:
  1. Divide their pilots into separate pools, one for the NG and one for the MAX
  2. Organise pilot rosters so that everyone flies both models sufficiently frequently to keep both type ratings current
  3. Provide refresher courses to keep pilots current on the model they do not fly regularly.
Or some combination of the above.

This would likely increase operational costs, which would put Boeing at a competitive disadvantage. All models of the Airbus A320 family have a common type rating.

It is telling that when it came to common type rating of pilots even the FAA was prepared to grant this only for a combination of Classic and NG or NG and MAX. This led to Southwest accelerating the retirement of its Classic fleet by acquiring 2nd hand NGs in advance of receiving any MAXs. It has also leaked out that Southwest's contract with Boeing for MAXs includes a penalty payment to Southwest of $1M per plane in the event of additional simulator training becoming necessary.

For those less familiar with the aviation industry while wide-bodies get lots of attention it's the narrow-bodies that generate the steady, almost easy, profits for both Airbus and Boeing. It is therefore essential, though perhaps not quite critical, that Boeing finds a way to restore confidence in the MAX. What little has so far leaked from the investigation suggests that it will be an uphill struggle for Boeing for quite some time.
 

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Perhaps Boeing could convert backorders for the 737 MAX into orders for a supposed 'Narrowbody 787'. Of course that would only be possible if they already had an advanced stage of design done behind closed doors, but if I was Boeing that's exactly what I would have been focusing on for the past 5 years — especially in light of the A380's struggles.
 

Bletchleyite

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Perhaps Boeing could convert backorders for the 737 MAX into orders for a supposed 'Narrowbody 787'. Of course that would only be possible if they already had an advanced stage of design done behind closed doors, but if I was Boeing that's exactly what I would have been focusing on for the past 5 years — especially in light of the A380's struggles.

They are, it seems, working on a 757/767 replacement which is I guess a slightly shrunk (but still twin-aisle) 787 - so one reduced further in size wouldn't seem the proverbial rocket science.

Actually, this: https://en.wikipedia.org/wiki/Boeing_Yellowstone_Project near enough confirms it, it's the "Y1", though it was put on a back burner by the 737 Max.
 
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