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Smoke in the cabin of two 737 MAX caused by Load Reduction Device system [video]

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Re: Smoke in the cabin of two 737 MAX caused by Load Reduction Device system [video]

#51

Post by beAbU »

pxeger1 wrote: post #50

This guy says he doesn’t understand why the issue isn’t taken more seriously, and that he’s tried to cover every possible hole in his logic. Here’s a possible reason: None of the sources he references about the danger of the smoke itself appear to be very confident that it genuinely could kill you in 39 seconds, and they all seem to be from sites that likely have an incentive to sensationalise. Maybe he had better so…

Or... Alternatively... This YouTube video is incentivised to sensationalise as well. It is on YouTube after all, and there is an algorithm to please.

Re: Smoke in the cabin of two 737 MAX caused by Load Reduction Device system [video]

#52

Post by beAbU »

dehrmann wrote: post #45

tl;dw: when a particular engine design used by the 737 MAX (but also other Boeing and Airbus planes) ingests a bird, if there's enough damage, it starts burning oil before the cabin bleed air intake. The cockpit and cabin have air supplied from different engines. Since the cockpit is relatively small, if the cockpit engine was damaged, smoke would fill the cockpit quickly, reducing the pilots' visibility and requirin…

>Regulators in the US and EU don't seem especially concerned

Presumably because a bird strike at TO would prompt an immediate go-around and land. With landings the runway is right there.

Not an aviation expert at all, so I am talking out of my ass on this.

Re: Smoke in the cabin of two 737 MAX caused by Load Reduction Device system [video]

#53

Post by agsnu »

beAbU wrote: post #52
dehrmann wrote: post #45

tl;dw: when a particular engine design used by the 737 MAX (but also other Boeing and Airbus planes) ingests a bird, if there's enough damage, it starts burning oil before the cabin bleed air intake. The cockpit and cabin have air supplied from different engines. Since the cockpit is relatively small, if the cockpit engine was damaged, smoke would fill the cockpit quickly, reducing the pilots' visibility and requirin…

>Regulators in the US and EU don't seem especially concerned Presumably because a bird strike at TO would prompt an immediate go-around and land. With landings the runway is right there. Not an aviation expert at all, so I am talking out of my ass on this.

Doesn't help you if the pilot flying is incapacitated by the toxic air in less than a minute, or crash in to mountains, as in the scenario posited in the video. Climbing out to an appropriate height to join the approach, reconfiguring the plane for landing etc, takes several minutes; an immediate forced 180 teardrop back to land is very challenging to execute successfully (see the tragedy at Jeju just before new year).

Re: Smoke in the cabin of two 737 MAX caused by Load Reduction Device system [video]

#54

Post by mrob »

pxeger1 wrote: post #50

This guy says he doesn’t understand why the issue isn’t taken more seriously, and that he’s tried to cover every possible hole in his logic. Here’s a possible reason: None of the sources he references about the danger of the smoke itself appear to be very confident that it genuinely could kill you in 39 seconds, and they all seem to be from sites that likely have an incentive to sensationalise. Maybe he had better so…

Even if it doesn't kill them, thick smoke in the cockpit is obviously going to impair pilot performance, and that's a big problem when it's most likely to happen during the most dangerous phases of flight (takeoff and landing) when they already have a lot to deal with. It seems strange to ignore it when the risk could be mitigated with a simple change of procedures.

Re: Smoke in the cabin of two 737 MAX caused by Load Reduction Device system [video]

#55

Post by fransje26 »

berkut wrote: post #19
dz0ny wrote: post #2

This is a issue that may also affect Airbus aircraft, but so far, it has only caused problems on two Boeing planes. Like MCAS, it was not disclosed to pilots, prompting the FAA to recommend design changes and notify flight crews. https://simpleflying.com/boeing-cfm-international-update-737...

It's not clear that is does affect Airbus does it? It looks like only the LEAP-1b engines are affected by this, and I was under the impression that LEAP-1b was 737-MAX-only? (A320 has LEAP-1a as far as I can see).

From [1], it looks like the 737 flight deck ventilation bypasses the mix manifold.

This does not seem to be the case for the A320 family of jets. [2]

[1] https://www.youtube.com/watch?v=AAy_ch6sfOQ&t=1707s

[2] https://youtu.be/4Yf-0_UTbRs?feature=shared&t=311

https://youtu.be/4Yf-0_UTbRs?feature=shared&t=311

Re: Smoke in the cabin of two 737 MAX caused by Load Reduction Device system [video]

#56

Post by jiggawatts »

MBCook wrote: post #40
V99 wrote: post #33

Earlier quoted context omitted.

Yes the FAA can issue what are called Airworthiness Directives and require an issue be resolved in the timeframe and manner they specify. The timeframe could be anything, but common forms are like: - Within the next X (flight) hours or Y calendar days - You don't have to, but additional inspection needed every X hours or Y days until you do - At next annual inspection - Immediate/before flying again (usually called a…

I know the FAA can, I was referring to the manufacture. If Boeing makes a software patch do they have any way of forcing everyone to install it other than asking the FAA to issue a directive?

AFAIK, no.

I read through the 787 Dreamliner manual for setting up the software for patch distribution to the planes, and there are checks and overrides at every step. The whole thing is physically controlled by the owning airline or maybe the leasing company, but not Boeing.

Re: Smoke in the cabin of two 737 MAX caused by Load Reduction Device system [video]

#57

Post by rounce »

agsnu wrote: post #53
beAbU wrote: post #52

Earlier quoted context omitted.

>Regulators in the US and EU don't seem especially concerned Presumably because a bird strike at TO would prompt an immediate go-around and land. With landings the runway is right there. Not an aviation expert at all, so I am talking out of my ass on this.

Doesn't help you if the pilot flying is incapacitated by the toxic air in less than a minute, or crash in to mountains, as in the scenario posited in the video. Climbing out to an appropriate height to join the approach, reconfiguring the plane for landing etc, takes several minutes; an immediate forced 180 teardrop back to land is very challenging to execute successfully (see the tragedy at Jeju just before new year…

They don’t have to be incapacitated, simply having to deal with reduced cockpit visibility and/or minor impairment during an emergency while in a critical phase of flight is a significant elevation of risk.

Re: Smoke in the cabin of two 737 MAX caused by Load Reduction Device system [video]

#58

Post by db48x »

K0balt wrote: post #7
dz0ny wrote: post #2

This is a issue that may also affect Airbus aircraft, but so far, it has only caused problems on two Boeing planes. Like MCAS, it was not disclosed to pilots, prompting the FAA to recommend design changes and notify flight crews. https://simpleflying.com/boeing-cfm-international-update-737...

Unfortunately, it seems that the internal FAA recommendations were not allowed to make their way into any kind of airworthiness directive. The recommendations include very basic procedure changes that mitigate the near term risks without any significant impact to operation, as well as recommendations for what probably amounts to a software change and upgrades to some of the pilot oxygen masks to effect a permanent fi…

> […] stops short of recommending some very, very simple steps in aircraft configuration prior to takeoff that would completely mitigate the issue […]

Well, the configuration changes during takeoff mitigate the issue if it happens during takeoff. If it happens at any other time then they don’t do anything to help.

> I can see no reason to drag feet on this recommendation […]

I can. Perhaps the FAA believes that it is better to minimize change fatigue. Since the problem can apparently be fixed in software, and Boeing has decided to make that fix, they might want to write just one airworthiness directive requiring everyone to install it instead of two, one telling pilots to adopt some procedure followed by another telling them to abandon it.

> (It is yet another difference from older 737 design , like the deadly MCAS system, that was not disclosed to pilots transitioning to the new aircraft)

Keep in mind that for most aircraft the airline can pick and choose between different engines. The pilots don’t have to learn the myriad different engineering decisions that go into those engines; from the pilot’s perspective they are supposed to be interchangeable.

Re: Smoke in the cabin of two 737 MAX caused by Load Reduction Device system [video]

#59

Post by db48x »

dehrmann wrote: post #45

tl;dw: when a particular engine design used by the 737 MAX (but also other Boeing and Airbus planes) ingests a bird, if there's enough damage, it starts burning oil before the cabin bleed air intake. The cockpit and cabin have air supplied from different engines. Since the cockpit is relatively small, if the cockpit engine was damaged, smoke would fill the cockpit quickly, reducing the pilots' visibility and requirin…

It’s not actually burning the oil, just dumping it into the airstream in the form of tiny droplets. Some of that gets sucked up by the bleed air system, the rest continues on to the combustion chambers to be burned.

Re: Smoke in the cabin of two 737 MAX caused by Load Reduction Device system [video]

#60

Post by dboreham »

aunty_helen wrote: post #43
adgjlsfhk1 wrote: post #36

Earlier quoted context omitted.

I think a lot of the problem here is that all of the forward looking design is looking at the 787 dreamliner where the air conditioning is done electrically rather than with bleed air. It seems entirely plausible to me that this situation arose due to a descoping halfway through the project, where an initial version of the design wasn't going to use bleed air, they then decided that doing that much design work would…

Nah bleed air is a pretty major system. 787 was a ground up design, so benefitted from lots of new tech. 737 max was something that they hoped wouldnt need a recert. So no this wasn’t the victim of a rescope.

But it was the victim of MBAs eating the world, since the 737-of-theseus concept wouldn't exist and we'd be flying in newer design planes.
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