Stranger

The Lev

What is incorrect about that statement?

• "the plane itself has serious stability issues" - FACT - at high angles of attack the placement of the engines can result in upward force on the aircraft that could result in a stall.
• "a very aggressive error prone system to stay in the sky" - FACT - the MCAS system uses the horizontal stabilizer to aggressively point the nose of the aircraft down and there have been multiple reports of faulty AOA readings causing the MCAs system to engage.
• "requires pilot routinely overriding this system required to keep the plane in the sky" - FACT - if there is a single faulty AOA reading (which has happened double digit times (OK maybe not quite "routinely")) and the MCAS system engage the aircraft will crash unless the pilot recognises the issue and manually resets the horizontal stabilizer.
• "it is not a pilot training issue but a flawed design issue" - in fairness, it is both. Relying on a single error-prone sensor is a flawed design. Arguably not ensuring that pilot input on the yoke could override the horizontal stabilizer impact is a flawed design. Keeping pilots in the dark about MCAs and its effects was an issue in the Lion Air crash, but should not have been an issue with Ethiopian. Training of the Ethiopian pilot may be an issue if they didn't know how to react to an MCAs "excursion" given the post Lion Air publicity.

trooper

OK..that is a fascinating claim... Love to know WHY Airbus industries would let a new purchaser "jump the queue"???

pitz

If the cumulative orders from AC and others, cause them to be able to build a business case for an additional FAL, certainly there could be some priority accorded to such orders.

AC may very well, by virtue of some of the highest RASM in the world, may very well be able to procure the reallocation of production slots from other carriers.

I blame AC's fleet planners and upper management though, for getting themselves into a position where there are serious business continuity questions if the 737Max ends up being grounded for a year or two. Or even permanently if consumer confidence in the aircraft is irreparably lost. The existing A320 fleet is basically the oldest in the world. They totally backed themselves into a corner.

5mm

RatherBeInYOW

Nice ad-homenim. I point out your BS and I get the "Boeing fanboy" label. Go re-read and show me where I am singing the praises of Boeing, I'll wait for the quote.

Try this:

1) You stated that ET is confirmed this is the same cause as Lion Air, and that the fix will take much longer and not just be in software. This is completely and utterly false and totally speculative at this point in time. We know there are some similarities between the two, but the Lion Air crash itself hasn't even had a report on the cause. Why make things up?

2) You stated that A320 NEO or A220 would be a short to medium term fix. And now you are "100% sure they can jump the queue and get some allocation" for the A220. Again why make things up? First of all the existing A220 doesn't meet the same requirements as the 737 MAX8, and second the idea that they could "100% sure they can jump the queue" is also false and totally speculative, and third the A220 production rates themselves won't come close to being able to recover and surpass the AC 737 MAX delivery schedule even if it was the same plane and they could jump the queue.

pitz

Just to clarify my remarks, if WestJet's 737Max8's didn't show up, all that would have been placed at risk would have been their expansion plans. Not a single plane in their fleet of 737NG's were at risk of forced retirements due to airworthiness issues.

With AC, if the 737Max8 issue isn't resolved imminently, they literally won't be able to meet their current customer demands. 5-10 A320-series aircraft *must* leave the fleet annually, if not more. They are absolutely and utterly reliant on receiving new aircraft, or alternatively, a significant recession occurring in demand.

RatherBeInYOW

FALSE. All this talk from armchair experts and you can't even correctly describe the reason for MCAS. In the shortest sentence possible MCAS is present because consistent pressure on the stick doesn't result in consistent AoA. Nearly every plane in the sky has automatic trim, including the 737NG and the A320 ... the 737 MAX just has very different trim characteristics and automation systems than the 737 NG which were not properly disclosed. That there is automated trim doesn't mean there are "serious ability issues" in the slightest, this is just ridiculous hyperbole.

FALSE. It doesn't require it to "stay in the sky" at all. Yes, it apparently is overly aggressive and can lead to runaway trim issues which are at the root of the problem with MCAS, but that doesn't mean it needs the system to "stay in the sky" any more than any other plane with automated trim does.

FALSE. Can you tell me how often MCAS has had pilots "routinely overriding the system to stay in the sky" of course you can't, because you don't know. But we know after hundreds of thousands of flights that it is absolutely not "routinely overridden".

FALSE. The fact is we don't know what it is. You can speculate on what it is but you don't have any idea because there is no report on crash causes issued so everything else is just supposition. It certainly looks like it was a combination flawed design, pilot training and maintenance issues in Lion Air, we haven't even seen real evidence in the ET case yet.

Everyone wants to run around and say the 737 MAX is completely doomed and AC should magically conjure up some A320 / A220s and fix their problems. Both of these statements are complete nonsense. The only thing you could rightly suppose is that AC is going to wait until there is some actual information on the 737 issues and proposed fixes before they do anything about anything, and that will take until at least the beginning of July. Maybe wait until we have some real information instead of making false and misleading statements about what has happened and is going to happen next?

Sebring

What is this? Amateur hour? The engaging of the MCAS system is entirely software driven, and a software fix, providing it is done properly, dispenses with the issue, just as a fix for lithium batteries not only ended the grounding of 787s but restored confidence in the aircraft. Does anyone hesitate to fly on a 787 today? They still have lithium batteries. And we still have lithium battery hazards in cell phones, so it's not like public awareness of lithium battery issues has dimmed. Even before the Lion Air crash, there was a simple workaround issue if the MCAS system pulled down the nose. On the flight in, the doomed Lion Air jet had a similar problem, but there was a deadheading pilot on board who advised the crew how to deal with it. The next morning, another crew took the plane up, encountered the same problem, and didn't know how to respond, resulting in the fatal crash. There is a hardware issue (AoA readings), a software issue (response to faulty readings) and a training issue (failure by Boeing to ensure crews worldwide understood the problem and the workaround). All three will be dealt with, and assuming they are dealt with properly, that will be it. People will fly in the Max, and 2-3 years from now people won't even remember this crisis any more than they will remember the grounding of 787s.

How AC decides to handle the legal aspect will be interesting. AC will undoubtedly sue Boeing as it has sued Airbus for the Halifax crash and other issues. Boeing undoubtedly expects lawsuits galore. I don't know if AC would rather have cash compensation or a restructuring of its Boeing order. I'm intrigued whether Airbus would use this as an opening to push ahead with an A220-500, yes the mythical stretch Boeing was always afraid of. It doesn't compete head-on with a Max 8, but starts to nibble at specific markets where a Max 8 might be just a bit bigger than the optimal size, a route where an A220-300 is too small, a Max 8 too large. AC will likely have some of those, and would IMO be a prime customer for an A220-500 since it would not really be an additional fleet type. There. I am playing Amateur hour now.

RangerNS

What is known now is the software considers input from a single sensor. The MCAS software runs on a particular black box; I recall reading some deep analysis that the sensor data may be fed to the MCAS black box through something else (for purposes here, the central computer?)

CPU cycles are not infinite. Analog sensor data needs wires to travel on. Digital buses have only so much bandwidth. Real time systems allocate cpu cycles and wire bits strictly, there may not be the computing power to just make a software fix.

Obviously, I have no idea the physical wiring infrastructure of the MAX systems.

If the MCAS gets direct analog input from sensors, then new wires need to be run, and it is not just a software fix.

If the sensors all feed onto a high speed digital bus, and already AoA sensor X>2 feeds into it, and the MCAS is attached to this bus, then its a matter of reading more data. Software alone might be a fix, and only in the MCAS box. This would be the best case scenario.

The MCAS box may not have enough CPU power to do the average/best/voting calculations to filter the sensor data. That is a hardware swap.

If the MCASs embedded CPU is 99% allocated to real time tasks now, it might not have the cycles to do more. Hardware swap.

If the sensors feed into some central computer (directly, or off a sufficient bus), then the central computer needs to write out that data. Minimally, that means software fixes on two black boxes. If the central box has enough CPU horsepower, and the central-MCAS bus is a reasonably abstract protocol with free space, the central box then has some minor updates, but we are now talking "just software", but on two boxes.

Also, possibly the interconnection between the central box and the MCAS box is, out of bandwidth; There may not be enough room on the wire for additional sensor data. If so, then the central box would need to calculate and feed the MCAS box some derivative value, and only possibly able to tell the MCAS box that it is suspicious of the calculated single value. Is that acceptable? That MCAS gets only corrected sensor data? That seems fine to me, but I don't know the industry rules. The central computer may or may not have enough free cycles to do this calculation. but it might already be doing it. Sending the corrected average over the wire would be a code change, but relatively easy. If it has to send 3 signals, more difficult. 1 signal + confidence, more difficult. But most likely, the central box requires code changes to change the data sent over the cpu-mcas wire, or if they are using a very low level protocol, a full change to the lowest level of data going over the wire.

So the "software only" fix could include additional physical wiring, and likely software changes on systems that are not the MCAS, and even potentially be impossible, if the embedded system resources are simply fully allocated.

yhzflyer

Oh, great. Now they're going to have to park the buses.

5mm

The Lev

AC has multiple optinos available to them to replace A320's that need to be scrapped - in addition to the MAX option they can still buy/lease used A320's or 737NG on the open market. These will be some what more expensive now and aren't as efficient as the MAX, but AC does have options. (Example being their recent purchase of Wow A321's).

You appear to be the only person who doesn't believe that MCAs was designed in large part to prevent stalls at high angle of attack. This article might refresh your memory:
"It was needed because the MAX’s much larger engines had to be placed farther forward on the wing, changing the airframe’s aerodynamic lift.

Designed to activate automatically only in the extreme flight situation of a high-speed stall, this extra kick downward of the nose would make the plane feel the same to a pilot as the older-model 737s."
https://www.seattletimes.com/busines...ion-air-crash/

I don't know and neither do you, however there have been many media reports beyond Lion Air and ET of pilots having to fight the MCAS system.


Just because the formal report isn't out yet, doesn't mean the industry hasn't formed a pretty clear idea of what some of the issues are. There may be more uncovered in the final report but even you have described problems with the MCAS system.

PS: I'm not one suggesting that AC conjure up other aircraft (other than as a temporary fill-in). I am confident that the MAX will fly again (safely).

JustSomeGuy1978

More an observation than a comment, however the OP seems to hint that AC moved towards boeing aircraft with its purchase of 737maxs (and 787s) from a previous preference for airbus. However in my limited knowledge I seem to recall that AC was a boeing/macdonald douglas airline and only switched airbus (320s, 330s, 340s) in the late 80s/early 90s due to influence from a pro French politician at the time.

AltaBound

There are plenty of aircraft available. The deserts in California and Arizona have storage yards for aircraft that are awaiting re-purposing. Remember this where the 767's in WestJet's fleet came from.

Has Boeing screwed up - Big Time.
Will the MAX disappear - No
Will Boeing survive this cluster... Yes