Boeing MAX production cut signals long grounding • Hacker News Board

Re: Boeing MAX production cut signals long grounding

#151

Post by cmurf » Mon, Apr 08, 2019, 5:33 AM UTC

matt-attack wrote: post #146

Obi_Juan_Kenobi wrote: post #116

Earlier quoted context omitted.

The electric trim adjustment is obviously going to be more powerful, that's just the reality of large planes. That's not the issue. The issue from the Ethiopian crash was that, in the extreme trim angle, there was simply too much force on the screw to turn manually. This condition is trained for, and the solution is to let the plan angle down to relieve the aerodynamic pressure on the control surface. That gives you…

Are you suggesting with the auto-trim disabled, the two pilots working together, with those handles extended on the trim wheel, were not strong enough to crank the trim wheel?

Yes. Known issue.

Scroll down slightly for the empennage diagram, right hand side, item 3.

https://www.seattletimes.com/business/boeing-aerospace/boein...

Re: Boeing MAX production cut signals long grounding

#152

Post by cmurf » Mon, Apr 08, 2019, 5:39 AM UTC

I think there's a non-zero chance that the 737 MAX is going to end up with a type certificate. MCAS causes the MAX to behave differently than an NG, whether it's working as designed or not. And also that it can be disabled, immediately means the airplane isn't airworthy as certified and without a type rating the pilot isn't either.

Before this article I would have said, approaches zero chance a type certificate would be required. But the idea it would take 6-8 months to get it flying again? That's so outside the realm of what I was expecting that there must be some talk about it.

Re: Boeing MAX production cut signals long grounding

#153

Post by kalleboo » Mon, Apr 08, 2019, 5:57 AM UTC

cryptonector wrote: post #138

DuskStar wrote: post #102

Earlier quoted context omitted.

What about it isn't fixable? Redundant (and thus more reliable) AOA sensors + a less aggressive MCAS system that at maximum displacement can't override the yoke would be more than enough of a fix for me.

No need to make MCAS less aggressive. Training + an alarm should be sufficient. Even now, with no other changes at all, training might well be sufficient, though I'd much rather they make the system more robust and add an alarm.

My minimum requirements would be:

* Manual MCAS cut-out switch that leaves the electronic trim available, without resorting to "hacks" like using the flaps.

* AoA disagree warning option on all planes, maybe even auto-cut out MCAS when disagree happens.

* Simulator training for all pilots on all MCAS failure scenarios and flying without MCAS.

Re: Boeing MAX production cut signals long grounding

#154

Post by mcv » Mon, Apr 08, 2019, 11:27 AM UTC

Svip wrote: post #66

wtvanhest wrote: post #28

Earlier quoted context omitted.

Was this aircraft even under FAA jurisdiction? I thought the FAA only had jurisdiction over airline flights to and from the US.

Certifying aircraft is a long and expensive process. So generally speaking, aviation authorities 'share the burden' by relying on each other. By the same token, the FAA will take an EASA certification of an Airbus aircraft as valid without much additional checking. FAA's reputation alone was good enough for other aviation authorities to accept its certification of Boeing's MAX 8, which is why the FAA matter despite h…

And both Boeing and the FAA have some credibility to win back here. If they don't, other aviation authorities might not trust the FAA's judgement on Boeing airplanes in the future.

Re: Boeing MAX production cut signals long grounding

#155

Post by mcv » Mon, Apr 08, 2019, 11:32 AM UTC

panarky wrote: post #3

Not only a longer grounding, but some airlines are canceling orders and many passengers don't want to fly in them. The 737 Max could become the Edsel of airplanes. https://en.wikipedia.org/wiki/Edsel

I'm honestly surprised they're not cutting back production more than this. If I was an airline that thought long and hard about whether to order the 737 Max or the Airbus A320neo, and ultimately decided on the Boeing, these events, and the likelihood of recertification and further training requirements for pilots might well make me reconsider that decision.

If Boeing really needed to cut these corners in order to remain competitive, then having to redo those corners might make them too expensive or inefficient for the market.

Re: Boeing MAX production cut signals long grounding

#156

Post by Retric » Mon, Apr 08, 2019, 12:57 PM UTC

jeltz wrote: post #99

Retric wrote: post #15

Earlier quoted context omitted.

Blaming EASA/FAA/Boing etc feels good, but calling them inept becase they are not perfect is overstating things. Looking back it seems like an obviously bad call, but that’s hindsight bias.

I did not blame FAA, I was just pointing out why your logic was flawed. Just because the plane crashes did not happen in the US does not mean that the FAA may not be at fault. The FAA had approved the plane and it was operated the same way in Africa as in the US so it is just chance that none of the crashes happened in the US.

FAA has many regulations that most of Africa does not.

So, no they where not operated in the same fashion. It’s still been grounded in the US for good reasons, but you can’t take individual regulations in isolation.

Re: Boeing MAX production cut signals long grounding

#157

Post by jaclaz » Mon, Apr 08, 2019, 1:33 PM UTC

iforgotpassword wrote: post #80

amartya916 wrote: post #36

Earlier quoted context omitted.

I do not know why you are getting the downvotes, but you are correct. The DoT and independent inspectors backed up this scenario. https://www.caranddriver.com/features/a15125313/its-all-your...

This doesn't mention the horrible spaghetti code NASA found when reviewing the code. 250k lines of C with thousands of global variables. It leaves a pretty bad taste. Then again, I still wouldn't be surprised if most people were just too perplexed if their car suddenly accelerated like crazy and not stay calm and hit the brakes as hard as possible right away. It might take you a second or two to get what's going on,…

>Then again, I still wouldn't be surprised if most people were just too perplexed if their car suddenly accelerated like crazy and not stay calm and hit the brakes as hard as possible right away. It might take you a second or two to get what's going on, and by then you might already have lost control.

Without electronics or software involved, many years ago (1980's or so) there was a FIAT diesel engine, that was widely used on mid-sized cars, typically the Ritmo (Strada in the US) that had a servo-brake working by depression coming from the engine that had a defective membrane.

Basically, it could happen that the membrane broke/got a hole in it and the oil from the engine would enter the combustion chamber, to the effect that the engine would go up at full revs.

And you couldn't switch it off, the only way was to depress the clutch pedal, put in fourth or fifth gear and brake hard while releasing quickly the clutch.

It was a terrifying experience for someone not very familiar with cars/engines, though most people using a manual gearbox know that by depressing the clutch and braking would stop the car (so no or few accidents caused by this issue), knowing how to forcibly turn off the engine wasn't (and still is not) common knowledge, the motor would continue going on for a few minutes until something else would break or the oil in the engine would have been mostly burned (leaving the engine with no lubrication at full revs) until the engine would seize up.

Re: Boeing MAX production cut signals long grounding

#158

Post by diminoten » Mon, Apr 08, 2019, 4:52 PM UTC

kazinator wrote: post #148

diminoten wrote: post #104

Earlier quoted context omitted.

This isn't a story, and I am not a character. If that's what you were using it like, you are wrong. It'd make at least some sense if you incorrectly meant "irony" in the sense that fucking with the FAA, which I said was bad, is how the MAX was made so poorly. Your fake choice of definition is even worse than what you actually meant.

It is possible to see irony in real world statements, actions and situations; "irony" is not strictly the name of several literary or dramatic devices.

Of course it's possible, it's just not present here. I never said irony was exclusive to narratives, I said the irony he's failing to accurately point out is.

Re: Boeing MAX production cut signals long grounding

#159

Post by cryptonector » Tue, Apr 09, 2019, 4:30 PM UTC

ulfw wrote: post #141

cryptonector wrote: post #138

Earlier quoted context omitted.

No need to make MCAS less aggressive. Training + an alarm should be sufficient. Even now, with no other changes at all, training might well be sufficient, though I'd much rather they make the system more robust and add an alarm.

No training in the world will help if this system malfunctions and puts the nose down at 1000ft already. You can't react fast enough to not hit the ground. Also I don't want to fly in a plane where 'trained' pilots have to fearfully watched every feet they climb to quickly overturn a system that malfunctions.

That's clearly not true, since the day before the Lion Air crash a pilot flying in the jump seat was able to diagnose and correct the issue.

Re: Boeing MAX production cut signals long grounding

#160

Post by cryptonector » Tue, Apr 09, 2019, 4:31 PM UTC

m_mueller wrote: post #110

DuskStar wrote: post #102

Earlier quoted context omitted.

What about it isn't fixable? Redundant (and thus more reliable) AOA sensors + a less aggressive MCAS system that at maximum displacement can't override the yoke would be more than enough of a fix for me.

Not GP but I'm mainly wondering about the likelihood of departure stalls with this design.

In the event that MCAS is disabled, the pilots will have to work harder to notice impending stalls and prevent them. Which is why this requires training.