Stranger

Jagboi

AC bought on price, as I'm sure did many other airlines especially considering pilot retraining. That likely wouldn't have changed if they had done a technical evaluation. Simply for pilot training and existing repair and maintenance operations it would have made sense to stick with the A320, buy we can only guess Boeing made AC an offer they couldn't refuse. I can't see the Engineers winning over the Accountants at AC.

WildcatYXU

IIRC it was a combination of price and availability. By the time AC placed the NB aircraft order, the NEO was already sold out for almost 4 years. I believe there were some claims made in this very topic that the NEO would be available 2 years later than the MAX.
Of course, it looks all different now. The savings may be gone due to this mess (despite the compensation that will undoubtedly come from Boeing) and the MAX may look not so great compared to the NEO after the promised PW1100 PIPs

Stranger

Stranger

WildcatYXU

Yes, I realize that it was AC's management who didn't select the NB replacement sooner. But I don't dare to blame anyone. It is a huge responsibility (we are talking what, $ 7 billion worth of aircraft at list prices?), so I guess they were analyzing the hell of both options. And honestly, if even a year ago somebody would say that the MAX will suffer two crashes with total loss partly attributable to the aircraft, this person would be declared insane. I have to say that even despite not being a 737 fan.

Stranger

RangerNS

Man, if only AV-Roe did not retool to make toasters.

bimmerdriver

It's both, but let's not quibble over this.

Here is what Boeing says in 737 MAX SOFTWARE UPDATE:

Boeing has said elsewhere that the portion of the flight envelope where MCAS is intended to operate is light load and aft CoG. In these conditions, the aircraft may exhibit higher AoA than desired, in which case, MCAS will command the stabilizers down by 2.5 units (IIRC) to correct the condition. The article doesn't provide much detail, but presumably the reason it refers to this as a matter of pitch stability, is because if down trim is not commanded, the AoA would keep increasing to the point of causing a stall, which obviously would not be a desired behaviour.

If there was no MCAS, the MAX would exhibit a tendency to climb faster than desired in the lightly loaded / aft CoG condition. If the pilot did nothing (i.e., did not ease up on the stick or command down trim, the stick shaker would eventually alert the pilot of a stall warning. If you consider that one single instance of 2.5 units of down trim is all that's required to correct this condition, it's not like the MAX has some sort of major pitch instability problem.

All this begs the question of why the original implementation of MCAS was so heavy handed (and so poorly implemented), but that topic is being beaten to death elsewhere.

bimmerdriver

I find it amusing that you apparently think you know more about aerodynamics than the engineers who designed the aircraft.

Stranger

pitz

CSA certification is only for products as they are initially presented for certification. There is no CSA inspector at every electrical consumer products factory that bears the CSA "certification". I think its a reasonable prospect for a customer to do due diligence on their CSA-"certified" products, to detect if there's been substitutions or alterations to the products that are outside of the scope of the original certification. I expect my local retailer to actually do some due diligence on whether the CSA stickers on the products they sell are real or not, especially if they come from places for which counterfeiting can be quite routine. I expect to have some responsibility myself in using common sense to determine whether a product reasonably meets in-service standards of quality and safety.

But, extended to a product like an airliner, if that role has been stripped away, or delegated entirely to external entities (that may be beholden to a vendor such as Boeing for technical or financial support ), then who is left to ask the hard questions of the vendors and the supply chain? How many airlines bought and took delivery of the 737Max with the horribly flawed MCAS design, and didn't push back? Taking Boeing's "word" for it that there was nothing wrong with the design? All of them. ~50 different airlines. Not a single one performed proper due diligence concerning Boeing's modifications. ET and Lion Air just happened to be the unlucky ones. It could've easily been AC involved in a major incident.

canopus27

OK.

Good job not quibbling

bimmerdriver

I know a bit about CSA certification (as well as the CE process, which is very different). When a product is produced to have a CSA mark it has to be made using suitable components and tested to ensure it meets the requirements. If it fails, the problems have to be fixed and then it has to be retested until it passes. When a product is produced outside of Canada (or the USA), there are two cases, high volume or low volume. For high volume production, they must undergo the same process. There are companies around the world that assist with the process. For low volume, they can undergo a field evaluation rather than the full CSA mark process. A field evaluation involves a review of the design (and components), as well as various operational tests. This can be done in the factory or when it's delivered. What's different about a field evaluation from getting a CSA mark is that the version of the electrical code it must comply with is a reduced scope document with a primary focus on safety. For this reason, a field evaluation is only allowed for low volume production. Either way, the testing is not performed by the end customer, but by qualified person from a qualified organization.

I agree with your comments about where were the airlines in this process and why didn't they push back on Boeing. I made this comment way back in this thread.

Fiordland

My experience with CSA certification is that in practice it tends to be very arbitrary. I have on multiple situations imported equipment into Canada that was not CSA certified as the original manufacture had no desire to do CSA. You end up having to have someone come in and do a special inspection and place there sticker. There are about a dozen companies authorized to inspect against the CSA standard. The level of depths can be quite variable from one inspector another.

I would hope aircraft are more systematic.