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

US refuses to ground Boeing 737 Max

bbc.com

Post reply on HN
Print view View original

311–320 of 344 posts

Re: US refuses to ground Boeing 737 Max

#311

Post by whack »

rorykoehler wrote: post #208
whack wrote: post #206

How does the plane's safety record compare against that of motorcycles or sub-compact cars? Should we ban them as well, until they can attain safety parity? My girlfriend has two intercontinental flights coming up in the next month. Flights that are very important to her life goals and fulfillment. I would hate to see a wrench thrown into those plans, because of a risk that she already takes on every weekend when she…

If cars are considered defective they are recalled. Happens often. Your comment is shockingly tone deaf.

Whether you choose to categorize a death being caused by "defects" or "user error" is ultimately irrelevant. Any system that's prone by design to user error should be considered equally defective.

Even with the two ambiguous incidents on Boeing 737, they are still far safer than the vehicles that people choose to ride everyday for pleasure. I will never ride a motorcycle myself, but would hate to see them banned nationwide.

I apologise if my comment is "tone deaf". I happen to think that public policy proposals should be fair game for constructive criticism.

Re: US refuses to ground Boeing 737 Max

#312

Post by kickopotomus »

buboard wrote: post #189
Emma_Goldman wrote: post #108

'But the FAA said that other civil aviation authorities had not "provided data to us that would warrant action".' Pretty sure the data is that two planes crashed in five months in perfect weather conditions, killing everyone on board. Statistically, that's sufficiently improbable that it warrants investigation.

> Statistically, that's sufficiently improbable Is it?

Yes, it is. The 737 NG (700 series, 800 series, etc) has a hull loss rate of 0.27 per million departures[0]. I am having difficulty finding the exact number of departures for the MAX but 737s average about 3-5 departures per day[1]. Only 350 MAXs have been delivered and the first one was delivered on May 6, 2017[2] (676 days ago). So even being generous and supposing that all 350 aircraft were delivered exactly on May 6, 2017 and that each plane made 5 flights daily, that would be a total of 1,183,000 flights. Therefore the MAX line has a best-case hull loss rate of 1.69 per million departures. I.e. the MAX generation has a hull loss rate 6.25 times that of the NG line.

[0]: https://en.wikipedia.org/wiki/Boeing_737#Accidents_and_incid...

[1]: https://www.researchgate.net/publication/274782362_Character...

[2]: https://en.wikipedia.org/wiki/Boeing_737_MAX

Re: US refuses to ground Boeing 737 Max

#313

Post by buboard »

kickopotomus wrote: post #312
buboard wrote: post #189

Earlier quoted context omitted.

> Statistically, that's sufficiently improbable Is it?

Yes, it is. The 737 NG (700 series, 800 series, etc) has a hull loss rate of 0.27 per million departures[0]. I am having difficulty finding the exact number of departures for the MAX but 737s average about 3-5 departures per day[1]. Only 350 MAXs have been delivered and the first one was delivered on May 6, 2017[2] (676 days ago). So even being generous and supposing that all 350 aircraft were delivered exactly on Ma…

the question is if this difference is statistically significant

Re: US refuses to ground Boeing 737 Max

#314

Post by dsfyu404ed »

freehunter wrote: post #300
dsfyu404ed wrote: post #175

Earlier quoted context omitted.

So in perfect conditions he's very likely to tell the rookie beside him to fly the plane so the rookie can rack up experience. Edit: Why is this being down-voted? Letting the new guy get experience this way is a common industry practice.

>Why is this being down-voted Because you're making a claim with absolutely no evidence that the captain sat by and watched a rookie crash a plane and kill everyone on board and the captain did nothing to intervene and save his own life.

>Because you're making a claim with absolutely no evidence that the captain sat by and watched a rookie crash a plane

Care to show me where I made that claim? All I said was that given the (good) conditions it was more likely (than any average minute of flight) that the less senior pilot was controlling the aircraft.

>and the captain did nothing to intervene and save his own life.

You mean like what happened the on the Air France A320 that wound up in the drink a few years back? It's perfectly possible that one pilot started fighting the MCAS system and both pilots actions in their attempts to deal with the situation combined in a way that resulted in the crash.

Re: US refuses to ground Boeing 737 Max

#315

Post by whack »

PhasmaFelis wrote: post #214
whack wrote: post #206

How does the plane's safety record compare against that of motorcycles or sub-compact cars? Should we ban them as well, until they can attain safety parity? My girlfriend has two intercontinental flights coming up in the next month. Flights that are very important to her life goals and fulfillment. I would hate to see a wrench thrown into those plans, because of a risk that she already takes on every weekend when she…

There are about 350 of these planes flying, and they've been in general use for about two years. That implies 1/350 odds of a fatal crash per plane per year. I can't find similar statistics for motorcycles, but that's still wildly unacceptable. And even if it weren't, you're arguing that problems can only be addressed one at a time in strict order of severity, in a nation of 326 million people. That's ridiculous.

https://www.iii.org/fact-statistic/facts-statistics-motorcyc...

The fatality rates are 25 per 100 million occupant-miles traveled. That's far higher than for the Boeing 737 max.

Let's also compare their safety by time, instead of miles traveled.

Motorcycles: 25 / (100 x 10^6 / 60) = 0.000015 fatal crashes per hour

Boeing 737 max, assuming it averages 12 hour flight time per day, and using your 1/350 odds: 1/(350 x 365 x 12) = 0.00000065 fatal crashes per hour

The 737 max is still safer by an entire order of magnitude, even if you compared it by time spent traveling and not miles.

Re: US refuses to ground Boeing 737 Max

#316

Post by 20after4 »

lqet wrote: post #291
chipsa wrote: post #209

Earlier quoted context omitted.

If he doesn't know how to correct for runaway stabilizer trim, then he probably should be decertified. It's a memory item: https://www.theairlinepilots.com/forumarchive/b737/b737memor... And the checklist is 4 items long. Item 3 disables MCAS.

I am curious regarding item 4: STABILIZER TRIM WHEEL - GRASP and HOLD How does the trim wheel work? Is it mechanically connected to the stabilizer?

Yes I believe it's mechanically connected.

Re: US refuses to ground Boeing 737 Max

#317

Post by _Codemonkeyism »

ComputerGuru wrote: post #174
_Codemonkeyism wrote: post #165

There will be a point in time when CEOs of those airlines in the US that do not ground 737 MAX planes get into a lot of trouble if something happens to one of their planes. Then they play with jail time instead of payments to victim relatives.

No, there won't. It's not a CEO's job to make kind of call because they're not expected to have that kind of insight into such technical safety matters. Their job is to run the company based off of what the experts tell them; the FAA is literally absolving companies of having to make the decision and shoulder the burden themselves.

Yes it is, the same way a CEO is responsible if the systems of the company are hacked and millions of emails and passwords are lost. They do what security experts tell them. Equifax for sure had lots of experts. Or Sony for that matter. There is a point when a court will decide that "you should have known" and the "expert" defense will not work.

It's funny on HN, if it's security the CEO should go to jail for listening to experts, if it's Boeing - one of the holy cows beside Tesla - it's "follow expert advice".

I bet $100 if an US 737 MAX crashes the CEO will go to jail.

Re: US refuses to ground Boeing 737 Max

#318

Post by ComputerGuru »

_Codemonkeyism wrote: post #317
ComputerGuru wrote: post #174

Earlier quoted context omitted.

No, there won't. It's not a CEO's job to make kind of call because they're not expected to have that kind of insight into such technical safety matters. Their job is to run the company based off of what the experts tell them; the FAA is literally absolving companies of having to make the decision and shoulder the burden themselves.

Yes it is, the same way a CEO is responsible if the systems of the company are hacked and millions of emails and passwords are lost. They do what security experts tell them. Equifax for sure had lots of experts. Or Sony for that matter. There is a point when a court will decide that "you should have known" and the "expert" defense will not work. It's funny on HN, if it's security the CEO should go to jail for listeni…

It's the difference between there being a regulatory agency that oversees these decisions and it not existing.

Re: US refuses to ground Boeing 737 Max

#319

Post by lqet »

20after4 wrote: post #316
lqet wrote: post #291

Earlier quoted context omitted.

I am curious regarding item 4: STABILIZER TRIM WHEEL - GRASP and HOLD How does the trim wheel work? Is it mechanically connected to the stabilizer?

Yes I believe it's mechanically connected.

Ok, so in the worst case you are still able to block the motor that does the automatic trimming with your bare hands. Which seems like a reasonable fall-back. Thanks!

Re: US refuses to ground Boeing 737 Max

#320

Post by racingmars »

lqet wrote: post #291
chipsa wrote: post #209

Earlier quoted context omitted.

If he doesn't know how to correct for runaway stabilizer trim, then he probably should be decertified. It's a memory item: https://www.theairlinepilots.com/forumarchive/b737/b737memor... And the checklist is 4 items long. Item 3 disables MCAS.

I am curious regarding item 4: STABILIZER TRIM WHEEL - GRASP and HOLD How does the trim wheel work? Is it mechanically connected to the stabilizer?

> How does the trim wheel work? Is it mechanically connected to the stabilizer?

On 737s, yes, the trim wheel is mechanically connected by cables. To quote the 737-800 FCOM:

"Manual stabilizer control is accomplished through cables which allow the pilot to position the stabilizer by rotating the stabilizer trim wheels. The stabilizer is held in position by two independent brake systems. Manual rotation of the trim wheels can be used to override autopilot or main electric trim. The effort required to manually rotate the stabilizer trim wheels may be higher under certain flight conditions. Grasping the stabilizer trim wheel will stop stabilizer trim motion."

Post reply on HN