Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Canada grounds Boeing 737 Max 8

cbc.ca

Post reply on HN
Print view View original

161–170 of 304 posts

Re: Canada grounds Boeing 737 Max 8

#161

Post by Scarbutt »

js2 wrote: post #59
vb6lives wrote: post #45

Earlier quoted context omitted.

They have more than 5000 orders for this model of aircraft. Each one costs approx 120million. Which means there are approx $640 billion dollars on the line. It is imperative that Boeing keeps it's reputation and grounding flights would destroy it.

Another 737 Max crashing in the face of the current scrutiny would destroy it even worse, wouldn’t it? Is that just a calculated gamble?

Is that just a calculated gamble?

Yes, because by now, every pilot still flying that plane has been trained to deal with the issue.

Re: Canada grounds Boeing 737 Max 8

#162

Post by dmix »

jsharf wrote: post #17
whatshisface wrote: post #5

Earlier quoted context omitted.

> I find it worrying that it took them so long to come to the obvious conclusion Aviation regulators and internet forums are literally at the opposite end of the spectrum with regards to jumping to conclusions.

Frankly, it hasn't even been a week. Thousands of flights happen every day, and these two accidents were 5 months apart. If it takes 2 weeks to make the decision, that actually sounds quite rushed. In the meantime every pilot on the planet is probably paying attention so they know what to do if they find themselves in the same situation, so likely the risk has already gone down slightly. I think that waiting 2 weeks…

Yep a lot of papers have mentioned how these groundings by airlines was a very rare occurrence. Especially without any FAA confirmation and the day after an accident.

Re: Canada grounds Boeing 737 Max 8

#163

Post by djsumdog »

lisper wrote: post #79
jostmey wrote: post #62

Earlier quoted context omitted.

My understanding is that the Boeing 737 max jet is unstable. Instead of redesigning a new plane from the ground up, Boeing placed the larger engines forward and upward on the wings. Boeing then tried to issue a "software patch" on a bad hardware design. Boeing came up with an automated system to seize control of the aircraft in the event that the flight became unstable and neglected to inform pilots of this new autom…

Private pilot here. That is exactly right, based on everything that I've read and heard from other pilots, some of whom fly the Max 8.

Other articles posted said there is a way to turn off the auto-correction, but it's not intuitive. On earlier 737s which had this, it came on when engaging automatic ascents/descents and was disabled when a pilot disabled those systems.

In the case of the Max8, it's always on and there is additional training needed to react quickly when this happens. I think all current pilots who are watching this situation should know what to do at this point, but the needed the awareness brought by the situation. In the two crashes so far, it seems like the pilots had years of commercial experience.

Re: Canada grounds Boeing 737 Max 8

#164

Post by Cacti »

peteretep wrote: post #85
js2 wrote: post #20

Having read many commments on HN and elsewhere since the crash, I know I’m in the minority here when I say this but to me it seems like the US airlines and FAA are following their procedures, the same procedures that make the US airlines the safest in the world, while the rest of the world is, I don’t quite want to use the word panicking, but at least giving into pressure from people who aren’t aviation safety expert…

> the US airlines the safest in the world Where do you people _get_ these ideas?!

There has been one death in the past decade of US commercial flights. One in a decade of over 90 million flights.

Re: Canada grounds Boeing 737 Max 8

#165

Post by cmurf »

jostmey wrote: post #62
mcv wrote: post #42

Earlier quoted context omitted.

From what I understand about the issue so far, the systemic flaw is not in the aircraft, but in the training of the pilots. Or the lack thereof. Boeing wanted the 737 MAX to be considered just another 737 that didn't require any new training, but there are apparently significant changes compared to other 737 models that leave pilots feeling ill-prepared.

My understanding is that the Boeing 737 max jet is unstable. Instead of redesigning a new plane from the ground up, Boeing placed the larger engines forward and upward on the wings. Boeing then tried to issue a "software patch" on a bad hardware design. Boeing came up with an automated system to seize control of the aircraft in the event that the flight became unstable and neglected to inform pilots of this new autom…

That is not accurate. There is a sufficiently different pitching moment in high angle of attack attitude that results in the engine nacelle producing lift. That means the flight characteristic of the MAX is sufficiently different to otherwise warrant its own type rating separate from previous 737 generation type rating. Boeing and FAA agreed to a software abstraction to obviate the need for a separate type rating for pilots.

The plane is not unstable. A pilot who is trained for the actual flight characteristics absolutely can handle the plane. The problem is they weren't required to get that training, because 737's still all share the same type rating as if they all have substantially the same flight characteristics. Which is generally true except one particular attitude, high angle of attack.

It's an open question to me (I'm no one, but I am a pilot and a flight instructor in a previous life) exactly how different stall avoidance could be with MCAS disabled (which is indirectly done by setting stabilizer trim to cutoff) once it has already induced a dive by having fought with it a little bit too long. If it's a normal procedure to disable the very software abstraction that means you don't need a type rating for this airplane, but the stall avoidance technique is substantially different from other 737s - that's very concerning to me. Not that the plane is unstable or unsafe. But that there's a disconnect in pilot knowledge and actual airplane flight characteristics with this abstraction turned off.

Re: Canada grounds Boeing 737 Max 8

#166

Post by JustSomeNobody »

rfugger wrote: post #86
JustSomeNobody wrote: post #57

Earlier quoted context omitted.

Maybe the operative word is validated, then.

If you're a regulator, and you have unvalidated data that suggests a plane may be unsafe, how long do you wait for validated data before deciding to ground that plane "out of an abundance of caution"?

Three days?

It's their job to keep people safe. They do that by looking at data they trust. I don't envy the position they're in this week one bit.

Re: Canada grounds Boeing 737 Max 8

#167

Post by amyjess »

elliekelly wrote: post #63
mcv wrote: post #42

Earlier quoted context omitted.

From what I understand about the issue so far, the systemic flaw is not in the aircraft, but in the training of the pilots. Or the lack thereof. Boeing wanted the 737 MAX to be considered just another 737 that didn't require any new training, but there are apparently significant changes compared to other 737 models that leave pilots feeling ill-prepared.

My understanding is that it's a bit of both. This Slate article[1] described it as both a design flaw and an effort to paper over that design flaw by tweaking the autopilot system. >Boeing swapped out the engines for new models, which, together with airframe tweaks, promised a 20 percent increase in fuel efficiency. In order to accommodate the engine’s larger diameter, Boeing engineers had to move the point where the…

> To prevent this, Boeing added a new autopilot system that would pitch the nose down if it looked like it was getting too high.

The biggest problem here is that the new autopilot system relies on a pair of Angle of Attack sensors. Those sensors are prone to damage, and if the sensor is damaged, the erroneous information it reports can engage the new autopilot system. One of the reasons why Southwest thinks it's immune to this problem, by the way, is because they paid extra for a system that displays an alert when the Angle of Attack sensors disagree with each other, so pilots are aware of what's wrong and can take action to stop it. Most other carriers, including Ethiopian and Lion Air, didn't.

Also, other autopilot systems can be disengaged by pulling back on the stick. This one can't: you have to manually disengage the system.

Pilots were never informed of any of this because Boeing wanted to maintain the fiction that the 737 MAX is no different than previous versions of the 737.

Re: Canada grounds Boeing 737 Max 8

#168

Post by helaoban »

peteretep wrote: post #85
js2 wrote: post #20

Having read many commments on HN and elsewhere since the crash, I know I’m in the minority here when I say this but to me it seems like the US airlines and FAA are following their procedures, the same procedures that make the US airlines the safest in the world, while the rest of the world is, I don’t quite want to use the word panicking, but at least giving into pressure from people who aren’t aviation safety expert…

> the US airlines the safest in the world Where do you people _get_ these ideas?!

Care to offer evidence to the contrary to support your incredulity?

Re: Canada grounds Boeing 737 Max 8

#169

Post by mikeash »

Twirrim wrote: post #158
mikeash wrote: post #113

Earlier quoted context omitted.

Maybe from the fact that the last fatality in a US airline crash was over ten years ago?

That's hardly a unique thing about US airline safety. You're building one heck of a fragile claim there to superiority, a number of other countries can make similar claims, including countries that have similar or better safety records. Just out of a quick wiki trawl over the last ten years: https://en.wikipedia.org/wiki/UPS_Airlines_Flight_1354 UPS airline plane crashed in 2013, killing all onboard. In the same year…

Are you really going to use a UPS crash as an argument here? You actually raise some good points but I can’t get past that one.

Re: Canada grounds Boeing 737 Max 8

#170

Post by djrogers »

komali2 wrote: post #41
isostatic wrote: post #27

Earlier quoted context omitted.

Non-paywall: https://www.theguardian.com/world/2019/mar/13/ethiopian-airl... > The airline is planning to send the 737 Max 8 plane’s flight data recorder to Europe rather than the US for analysis, he said. That seems to be shocking news. Is it that they don't trust the FAA?

Also, why not both? Is the data in some... Non-copyable format? Is the physical device needed for some reason?

No, once the data is extracted it can be sent to any/everyone. One team has to be responsible for extracting the data though - it's not simply popping out an SD card and plugging it in to your MacBook like a DSLR, especially with potential damage to the device.
Post reply on HN