Knowing this, how fixable is the 737 MAX technically and politically?
FFS flying is stressful enough in general - but when you have specific events (the crashes) and specific evidence of corporate [corruption/concealment/negligence/malfeasance or whatever the truth is within Boeing] which detracts from the faith in the safety of their life critical product(s) -- it has just destroyed a fair amount of trust in the company and the industry as a whole.
Not to detract from your points, but if you have any inclination to anxiety, yeah flying is stress-inducing.
The valsalva maneuver seems to work the best for me but it doesn't always work and is often painful.
- The stress of getting to the airport on time, and finding transportation from the airport to my destination.
- Standing in line for security checks together with hundreds of strangers, all impatiently waiting and shuffling in line.
- Waiting until boarding begins, trying to relax but at the same time trying to check of the gate doesn't change at the last moment.
- Getting crammed in seats that are too small, and having to sit there for hours.
- The high-pitched noise of the jet engines works on my nerves. Noise-isolating earbuds or noise-cancelling work wonders for that, luckily.
- Changes in air pressure often hurt my ears, and it sometimes (when I have a bit of a cold) takes a few days to disappear completely.
- I get airsick sometimes, especially in rather strong turbulence, so turbulence stresses me out too. Fortunately there are medications that work pretty well.
Not a lot of that is caused by the flying itself. Taking the Eurostar across the Channel for example has much of the same unpleasantness. And I imagine flying in a private jet or a Singapore Airlines A380 First Class Suite (as in https://www.youtube.com/watch?v=_O2_nTt1N6w) can be very pleasant.
You're not supposed to fly when you have a cold. Any existing swelling in the sinuses or ears can result in long-lasting injury. Usually that means ruptured ear drums, but the sinuses can be affected.
Pilots with a cold certainly cancel their flights.
I once told a friend with a cold to cancel his flight and take a 24-hour bus ride. He laughed it off and flew anyway. When I saw him a week later, he was still in pain.
All they really need to do is recertify the entire aircraft, which is no small task.
Boeing is too big to fail and too powerful to punish so nothing will really happen. If it was a Chinese company it would be banned from the US. As a US company it will go on like nothing happened. Well maybe the engineers who refused to sign will be fired. Give it some time and a "fix" will be made and the MAX will fly again.
And in this case, there are non-US regulators in play too. They used to just blindly trust the FAA and approve anything the FAA approved, but that has likely changed now - the FAA (rightfully) lost a lot of trust due to this. Pressuring the FAA into approving another unsafe design isn't enough anymore.
I suspect that if the FAA approves but EASA doesn't, many other authorities will be heavily inclined to trust EASA on this one. Which could make the plane a "US only" plane. Maybe some close allies could be pressured into allowing it but I doubt any airline outside of North America could meaningfully integrate them into their fleet with a different type rating and a small set of countries that allow them.
But rebuilding the trust will be harder.
"Most pilots are not very likely to experience a cabin pressurization problem and the associated warning horn at any time during their line flying.
The Board also considered the role of stress that probably further contributed to the possible confusion of the two meanings of the warning horn. In general, stress, such as that caused by the onset of a loud, distracting alarm in the cockpit, combined with the element of surprise, is known to lead to automatic reactions. Automatic reactions, in turn, are typically those that result from experience and frequency of encounter and are therefore not always appropriate. The Board considered that the flight crew may have automatically reverted to a reaction based on memory before consciously processing the source and significance of the stress factor. This would also explain why the flight crew failed to realize the improbability of their interpretation of the horn as a takeoff configuration horn and why they failed to move on to gathering information for a new, correct diagnosis of the problem at hand."
That particular stable door got closed, but at the time it was cited by pilots as an example of legacy design that wouldn't have been permitted on a clean-sheet airliner.
[1] https://en.wikipedia.org/wiki/Helios_Airways_Flight_522#Flig...
If the "fix" is to not do that, then the 737 MAX is not fixable because it loses the entire reason for its existence.
There are a ton of existing 737 MAX, and Boeing's production lines are all geared up to produce more. The MCAS etc are there so that it could be called a 737, but the "entire reason for its existence" was to mount larger more fuel-efficient engines.
On a 737 type. Not on a completely different type which would require retraining all 737 crew and lose months worth of flight time. Even less so for companies like Southwest which fly 737s exclusively.
Also, "Typically, once an airline takes the aircraft, Boeing makes some guarantees in terms of the performance of that aircraft, and one of them is that the aircraft should be airworthy," says Chris Higgins, an analyst at Morningstar [0]. So even the other half that is already sold isn't necessarily sunk for them as they have contractual obligations that will cost them if the planes have to get scrapped.
[0]: https://www.npr.org/2019/03/13/703189895/for-boeing-costs-of...
MCAS wasn't added because the plane didn't fly the same as the 737. MCAS was added because the plane didn't fly the same as all other certifiable aircraft. It doesn't meet FAA regulations on how the controls need to feel when approaching stall.
The type rating mess only caused Boeing to hide MCAS from pilots. This triggered various dangerous design decisions, including designing it to be impossible to disable and making it only take data from one sensor.
* It was undocumented.
* It had too much control authority. It was able to adjust the trim such that the elevator could not overcome the trim's pitch-down force, and such that the average pilot did not have enough strength to use the manual trim wheel to neutralize the trim in a dive.
* They removed the switch to turn it off. On older 737s, there's one switch to turn off automated control of stabilizer trim, and another to disconnect power to the motor, completely disabling electric trim. On the Max, both switches perform the latter function.
* They made it rely on only one sensor. I can't imagine the logic for that since two sensors are physically present, and damage to AOA sensors is not rare.
* The AOA disagree warning light, which would have clued pilots in to the presence of a faulty sensor was not present in most aircraft, despite documentation to the contrary.
The logic for that is really simple: each sensor is wired to one of the two computers. Each computer uses its own sensor. This was an already existing design, MCAS is just a new function added to these computers.
(AFAIK, other aircraft like Airbus have multiple sensors wired to each computer, so for them it would be natural to use more than one sensor.)
This is how they implement the AoA disagree function (the one which was broken in 90% of MAXes for unrelated reasons). It's also how they managed to implement a software update which makes MCAS take data from both sensors.
The logic for not implementing both sensors is much more insidious.
If you implement both sensors, then you have to deal with the case that infomation from sensors might disagree. The computer has no idea sensor is providing correct data, so the only thing it can really do is disable itself when the sensors disagree.
If MCAS has the ability to disable itself, then it must provide feedback to pilots it has done so, and have pilots follow some procedures. If there were procedures, then Boeing would have to add pilot training about what MCAS was and how things would be different when it disabled itself.
Boeing made it rely on only a single sensor to bypass training requirements.
You can't just add a switch to suddenly turn the aircraft into an illegal one. Any sane pilot would immediately turn it off for their own safety or be coerced to turn it off after launch by the airline companies. All the manufacturers would add an MCAS equivalent system to skip regulations. In the past the F1 went through this bullshit where cars were legal before the race started and the race ended with all cars turning on illegal features.
It's not like turning MCAS off makes the plane go faster or burn less fuel. Nobody would turn it off unless it was malfunctioning.
My understanding for that is that if you look at two sensors, then a disagreement can happen, which has to be resolved somehow. In the case of MCAS, this would likely be turning MCAS off and telling the pilot, which would require training on what that extra warning light meant and would have required telling the pilots about it, jeopardizing the type rating.
Looking at only one sensor means the system "cannot fail"...