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Comment by tomglynch | Hacker News Reader

This type of information is very convenient for Boeing...

Edit: It's likely true, but surely nearly every airline had a pilot 'warn of dangers'. But why is this a news story being promoted?

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Why is it convenient for Boeing?

Boeing is trying to claim inadequate training (by the airlines) is the problem, not the fact the MCAS software bandaid had serious design flaws yet Boeing pushed for it in order to compete with Airbus.

If poor training was the cause the plane shouldn't have received the same type number. So this is all still on Boeing. Boeing also specifically told these planes with the benefit that only a few hours of training would be enough.

I'm not seeing how this is beneficial for Boeing.

I'm starting to think a plane that can't glide during a emergency because they decided to deny physics is just not a good design.

The 737 can glide as fine as a plane of that size can. The MAX didn't change anything at that and no one was denying physics. The problem was the MCAS, which as a result of a single sensor malfunction would aggressively point the nose down via the stabilizer trim.

Yep, the reason they implemented MCAS was because they popped on some larger engines, which were too close to the ground, so they moved them up and forward on the wing a bit. This gave the plane a tendency to tilt up which could cause a stall, so Boeing added some software to bring the nose down.

In both crashes, one of the two Angle of Attack sensors was incorrect. Boeing only use one AoA sensor per flight (alternating for some bewildering reason), and in this particular flight it was constantly incorrectly stating the plane was nearing a stall. So MCAS would continually kick in until the Pilot could no longer keep the plane in the air.

> "This gave the plane a tendency to tilt up which could cause a stall"

That tendency also exists on Classic and NG 737's, and is something pilots are trained to compensate for. The issue with the MAX is the degree of this tendency changed. MCAS was meant to emulate the old (less severe) behavior.

Couldn't Boeing just put in a bunch of gyroscopes into the chassis and use that as a backup AoA sensor? (I am not a pilot so I have no clue if that is reasonable)

The plane attitude (what you can sense with gyros) and angle of attack are very different things. They only coincide in level flight with no wind (the attitude is measured to the earth frame of reference (transposed by gyros) and the AoA is measured with reference to the local wind stream)

OK then why not put a couple extra AoA sensors in? I thought everything critical on airliners was supposedly redundant?

From what I've read the Max has 2 AoA sensors, but reads from only 1 at a time, and MCAS chooses that 1 sensor randomly.

Indeed, part of this story is that the MCAS system was not classified as "critial" (i.e., a system which can cause a crash if it fails). If it had been, then it would have faced additional scrutiny and they'd probably needed three AoA sensors and majority voting. Apparently the authority of the MCAS system was increased during development, with the criticality judgement based on the old smaller value.

https://www.wsj.com/articles/faa-saw-737-max-flight-control-...

That is not what is wrong with the plane.

This has very little to do with the plane's ability to glide. (A 737 glides just fine, if a bit steep for my taste).

In that particular emergency, the control surfaces prevent it from gliding. You can even have issues on a Cessna - loss of elevator is not fun.[1]

It's not about "denying physics", it's about having insufficient redundancy[2] and improper amount of control from MCAS - 3 times more than the FAA approved: [3]

No plane is 100% safe. Boeing made this one worse for the sake of saving money - the physics work out just fine, and gliding ability is not really impacted. (But I don't think it'd be a normal response - I can't imagine a pilot thinking "oh, I'm getting a stall warning with nose down at 4,000 feet, I know, I'll cut power and glide".)

[1] https://airfactsjournal.com/2018/12/elevator-failure-at-4500...

[2] https://www.seattletimes.com/business/boeing-aerospace/a-lac...

[3] https://www.seattletimes.com/business/boeing-aerospace/faile...

Boeing seem to be pushing part of the blame to the pilot's -"Pilot error" - but this isn't due to 'lack of training' but the fact there was NO training and MCAS was not included in the manuals [1][2].

[1] https://www.seattletimes.com/business/boeing-aerospace/u-s-p...

> Jon Weaks, president of the Southwest Airlines Pilots Association, said Monday the airline and the pilots “were kept in the dark.”

“We do not like the fact that a new system was put on the aircraft and wasn’t disclosed to anyone or put in the manuals,” he said in an interview. What’s more, he noted, Boeing and the Federal Aviation Administration have now warned “that the system may not be performing as it should.”

[2] https://theaircurrent.com/aviation-safety/what-is-the-boeing...

> "Since it operates in situations where the aircraft is under relatively high g load and near stall, a pilot should never see the operation of MCAS. As such, Boeing did not include an MCAS description in its FCOM. The explainer continues: "In this case, MCAS will trim nose as designed to assist the pilot during recover, likely going unnoticed by the pilot."

There is another explanation, according to a Tuesday report in The Wall Street Journal: "One high-ranking Boeing official said the company had decided against disclosing more details to cockpit crews due to concerns about inundating average pilots with too much information - and significantly more technical data - than they needed or could digest."

Because it focuses blame on the airlines and pilots for executing poor judgment, and suggests that Boeing didn't create any risk that the downstream parties weren't aware of or in control of.

In one it helps them, pushing the narrative that more training would have avoided the disaster, on the other hand this questions if MAX should have been approved by FAA as a 737 variant that does not require re-training.

If I'm not mistaken, Boeing themselves were the auditor for this on behalf of the FAA.

It is both. FAA establishes guidelines for planes and designs to meet, and the airlines (not just Boeing) are responsible for certifying and rating their planes according to those guidelines.

This is not simply a case of regulatory capture, the FAA simply doesn't have the expertise and in-depth knowledge to perform completely independent verification. Requiring the FAA to do so might be prohibitively expensive, so this arrangement is the result of pragmatic realism more than regulatory capture. It does require a great amount of trust between all partners though, and it seems to me Boeing has been more than happy to skirt their responsibility in this case.

You say airlines, but I think you mean airplane manufacturers?

Perhaps the airplane manufacturer and certifier should be separate manufacturers?

How is the NHTSA able to certify crash tests for every make and model vehicle sold each year?

The FAA delegate much of the certification to Boeing [1], and to me it seems either the FAA is underfunded, or Boeing was in bed with the FAA to push things through quicker.

[1] https://www.seattletimes.com/business/boeing-aerospace/faile...

The only reason the FAA delegates is because they could no longer pay a competitive salary to retain aeronautical engineering talent given the better pay in the private sector. So they delegated.

This completely missing the point of independent certification, validation, and acting as a proxy for the "customer of first resort" is the entire point of a regulator. If you can't sell an independently staffed regulator on your design, flying their own test regime, you shouldn't be making planes period. The new regime basically relegated the FAA to the role of paperwork auditor; a reactive instead of proactive regulatory process.

sorry, yes, I meant manufacturers. Thanks!

They claimed that no training was required to fly this plane (a requirement of it being able to retain the 737 type rating). If it does in fact require additional training then that's very bad for their narrative.

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