Back to Squawk list
  • 55

Boeing's MCAS on the 737 MAX may not have been needed at all

This postscript to the most severe safety crisis in Boeing's history outlines the moments, milestones, and catastrophic missteps that lead to MCAS's fateful implementation. Yet the saga of MCAS lives on with one haunting realization: according to FAA Administrator Steve Dickson, in a sentiment shared by many European regulators, the system may not have been necessary at all. ( More...

Sort type: [Top] [Newest]

Rico van Dijk 22
Good! Take it out please! And if you’re at it, Boeing, take that most annoying Speed trim system on the NG series out as well please. I Don’t need any help when flying manual; you can have the trim when in autopilot, when it’s off, it’s mine thank you very much.
Silent Bob 9
I've never really understood the speed trim function's purpose. I'm accelerating to clean up after takeoff, and it wants to trim nose up? Dafuq?
No kidding! Dumbest system ever. Here’s a hint Boeing, if you need a handling reference, use the 727! Nicest flying transport jet ever built.
Hi; would you explain this for us vicarious-only pilots?
bobinson66 5
As I got to the end of the article, something popped out at me. FAA Administrator Steve Dickson wondered why Boeing didn't simply ask the FAA for a waiver similar to the situation between the flight characteristics between the 757 and 767. The article said that with those two planes, one handles like an "overpowered hotrod" and the other handles like a "whale". My thought was that Boeing would first have to spell out in detail the handling differences between the 737 NG and the MAX with the result being the possible denial of the waiver. Boeing never wanted to take that chance, and decided to move forward with the secretive MCAS.

Then, the FAA weighed in after the article's publication and stated that the handling characteristics of the non-MCAS MAX would not have been compliant.

My question is this: Is the handling difference between the 737 NG and the MCAS disabled 373 MAX more pronounced than the handling characteristic differences between the 757 and 767? Is the FAA throwing a bone to Boeing's investors by saying that the MCAS wasn't a waste of time?
dilkie 12
1. Marketing can kill
2. MBA's can kill
3. Customer demands can kill
4. Boeing should have invested in a new design much earlier rather than hording money and trying to cut corners playing catchup.
Rock Pinard -1
I agree 200 % with you
Sojo Hendrix 5
Finally an article explaining the stall characteristics always mentioned regarding MCAS but never elaborated on. And MCAS wasn't even needed? Wow. Dear Boeing, "Oh what a tangled web we weave, when first we practice to deceive." - Sir Walter Scott
mbazell 2
The pilot has final authority as to how the airplane should fly, not a computer designed by engineers, most of whom don't even have a pilot's license. For decades the pilot was the anti-stall system For decades the pilot (navigator) found his/her way around the world without a computer. For decades the pilot calculated how much fuel to put on board. Next thing you know a computer hooked to a light sensor will decide how to set the cockpit lighting for you.
sparkie624 5
The difference between and Boeing and Airbus is clear and concise.

Boeing believes that the PIC has the final authority authority of the control of the plane
Airbus believes that the computer should have final authority of the control of the plane.
CharlesRamsey 1
There’s always a tipping point. By going overboard on tech, Boeing arrogance voided the principle that’s ruled Aviation since the Wright Brothers...PIC has sole Responsibility for any final decision. MCAS overrode that premise.
An iconic American company nearly got ruined by bad training at two Asian airlines.
Scott Hawthorn -4
No, bad/careless design, money grubbing Boeing (no training at all on this system). Your remark is insulting to all non-American pilots.
user3956 3
I read somewhere that there was some relevant training offered as part of the sale which those airlines declined to purchase? If that's the case, I do blame Boeing however for making it not included as a standard aspect of the plane's package. Boeing has also had a well-known horrible culture lately from the execs of trying to get rid of engineers to save money. I'd like to ask them how much money they saved doing that...
sparkie624 1
No real surprise... the only 2 that needed it were the ones that only had 1 AOA vane, and the crews apparently were not properly trained on how to handle it.... It apparently happened before to the crew who flew the 2nd plane in and wrote it up. Maintenance did a repair, signed it off and the repair was a no fix... and that crew did not recognize that it was a system failure.
Not factually correct. All MAX planes have 2 AOA sensors; all had just one active. Some planes (not the two that crashed) were fitted with a difference warning light, an extra cost option.
sparkie624 -7
No... the 2 that crashed only had 1 AOA Vane!
Not true.
You can look it up. It's just wrong.
One of the sources of confusion in the Asian crash was the fact that the system switched automatically from one to the other at each stop.
user3956 2
It's amazing how many people continue to argue such a strange invalid concept as there just being one...
Doug Gilbert -2
Seems to illustrate systematic short-term focus by the company. There is only so long that one can kick the can down the road with product innovation.
Barry Kennelly -4
Please someone answer me one simple question.. Could Sully have landed a 737 MAX on the Hudson with sudden loss of power? If not, the MAX doesn’t pass the “Pub” Test and should not be certified.
sparkie624 9
Most Certainly and it would have been much easier... He would have had a Yolk instead of a Joystick/Game Controller!
That case has nothing to do with this.

[This comment has been downvoted. Show anyway.]

Greg S 7
MCAS is still present, it has not been deactivated. You didn't read the article, did you?
Be serious. It’s still present but much diminished and can’t be relied on to operate as needed.
Greg S 5
If you read the article you wouldn't say that. The whole point of the article is that MCAS is not needed at all:

"“We also pushed the aircraft to its limits during flight tests, assessed the behavior of the aircraft in failure scenarios, and could confirm that the aircraft is stable and has no tendency to pitch-up even without the MCAS,” said Ky.
The article actually points to confusion. The engineers at Boeing are being told it's "unacceptable" and ask for the test flight data to support it (as they should) and as a result they expanded MCAS. But an airline chief pilot flying the plane and concluding that it's handling is acceptable is not really testing under comparable flight conditions (weight, CG, alt, speed...etc). To compare flight dynamics you really need to adhere to a rigorous test plan in order to get valid data.
Which is just propaganda aimed at the conundrum.
Greg S 6
So you're claiming that US *and* European regulators are putting out propaganda for Boeing, that the plane is in fact "technically airworthy"? How did you reach this conclusion? Do you have any facts to back this up?
The most striking fact is the original contract provision with Southwest that called for a $1M penalty if it turned out that some specified level of pilot training would be necessary. That’s $1million per airplane. The whole point was to paper over differences with other differences, the disclosure and explanation of which would have required training. The changes to MCAS don’t affect those fundamentals. Maybe the new training mitigates them. We’ll see.
$1million per, or less than 1% of MSRP.
Greg S 3
I was asking you to back up your statements that the aircraft is "technically unworthy" and that European and US regulators were putting out propaganda for Boeing. I gather from your nonresponse that you are unable to do so.
Actually the Boeing engineers concluded that the MCAS was required according to their flight test data. It's interesting but ultimately irrelevant what other pilots under non-test-flight conditions conclude regarding a planes stability as you need to prove this under a multitude of flight conditions.
Silent Bob 4
The problem is there can obviously be a disconnect between "data" and actual performance. From what I understand the need for MCAS was driven by a requirement for control force gradient to be similar on the Max vs NG. When approaching stall AOA the amount of force on the elevator had to increase at a minimum value to make it harder to further increase AOA. Flight test data showed the Max did not achieve this requirement, and so MCAS was designed and implemented. The problem appears to be that while computer lines of code showed a deficiency, in real world flight the difference in feel to the pilots was not enough to be noticed.

Now you can't fault the engineers on this one, not for creating MCAS I mean. They operate in a black and white world where either the design meets specs or it doesn't. So in essence they were forced to "fix" a problem that didn't really exist.
No, my argument is based on logic. Not that the plane is “unworthy” but that its airworthiness depended, as originally certified, on a system that is now deactivated when it might be needed. The
You have your wires crossed. It's not deactivated, it activates less often. The less active version is the original design.
Please. It activates once; then not again. Once activated, it is deactivated.
Sorry, but you're wrong because it's only active during activation and only activates again if reactivated. The fact that the system is not active while inactive is a given.

Explaining stuff to you is like trying to nail jello to a tree, you know that?
Silent Bob 5
Are you daft, man? This whole fiasco happened because MCAS was never intended to operate the way it did before the grounding. It was only supposed to activate once, with limited control over the trim, per occurrence. Instead those protections were designed out for some unknown reason allowing MCAS to continually activate and run the trim to full nose down.

The new software restores the original design limitations, as well as updates the system to require both AOA inputs to agree before it will activate.

To suggest otherwise is pure intellectual dishonesty and/or a complete misunderstanding of how MCAS works.


Don't have an account? Register now (free) for customized features, flight alerts, and more!
Did you know that FlightAware flight tracking is supported by advertising?
You can help us keep FlightAware free by allowing ads from We work hard to keep our advertising relevant and unobtrusive to create a great experience. It's quick and easy to whitelist ads on FlightAware or please consider our premium accounts.