Why FAA and EASA didn't require any procedure changes in the interim to prevent the issue is a very good question.
I like Mentor Pilot and Air Disasters, so I know I’ve heard of a few where the problem that caused an accident was already known and a fix was available but the airline just chose not to do it because they had that option. Or it was scheduled but hadn’t been performed yet because it wasn’t thought to be that critical.
Having the FAA mandate the fix seems like it would be a much better option.
https://simpleflying.com/boeing-cfm-international-update-737...
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 fix.
The only reason that we even know about the internal recommendations is that they were leaked to the press.
Boeing released a pilot bulletin that basically says to go through the checklist quickly and to treat smoke in the cabin as a major failure, but stops short of recommending some very, very simple steps in aircraft configuration prior to takeoff that would completely mitigate the issue without negatively effecting flight performance.
The major recommendation in the internal FAA bulletin is to use the APU bleed instead of the main engine bleed air to power the air conditioning and cabin pressurisation during the takeoff phase of flight, below 3000 feet AGL. I can see no reason to drag feet on this recommendation, other than the uncomfortable suggestion that perhaps this issue should have been addressed during certification. (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)
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.
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).
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
Boeing has gone off the rails, but the general lack of nuance in the common narrative about their failures is really over the top.
MCAS is how a fundamentally different plane behaves (in most cases) like a normal 737. The fact that such a system exists is described, and disclosed, in minute detail to pilots when they get their mandatory training on the 737-MAX.
The specific name wasn’t used in the training, and that’s where this ridiculous narrative came from.
MCAS uses the same hardware but has different scenarios in which it activates and has a different effect. Not knowing of the existence of MCAS and not having a viable procedure to deactivate it if it went haywire was critical to the two accidents. I've looked into this a lot and to my knowledge this was never disclosed to pilots.
Can you provide a reference to MCAS being disclosed prior to the two accidents?
- CFM designed an engine that, in certain emergencies, dumps oil into the quite possible (actually traditional, if I understand correctly?) human-breathing stream of the aircraft, apparently, without the relevant human-breathing system shutdown mandate when said (or any) emergency system is triggered; [truth be told, we never heard their complete story]
- Boeing integrating said new engines into their new 737MAX without appropriately checking for possible new emergency mode interactions with their life-support (in this case, breathing) systems.
- FAA dropped the ball upon accident investigation;
- FAA removed their employee that then picked up the ball;
- EASA swallowing what they were told by FAA without asking further questions;
Well...
I have worked in many no-harm potential software projects that employed more careful engineering than this.
All hardware projects I worked on employed more careful engineering than this.
Conclusion: It becomes more and more difficult to falsify that Boeing, nowadays, simply abandoned engineering design reviews, and, relies solely on some blend of "agile" methods to design people-carrying airplanes.
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.
Comments on that youtube video are filled with industry insiders and it’s just wild. They even think someone has died from a similar fuming event back in December…
The part about filling the cabin with smoke because they couldn’t be bothered to make the software that detects the extreme vibration tell the AC units from that engine to shut down (which they already do if the rpm drops, indicating an engine failure-just not soon enough or reliable enough to prevent the smoke issue) - not so much.
The system for the ECU to detect the engine mount failure condition already exists. The function to shut down the air handlers in response to a different indicator of engine failure already exists in the ECU. It’s just literally “also shut down if the engine mounts fail”, but the guys that sit around and think about the what ifs were given early retirement to make room for more MBAs.
Sure, I get that it was added to prevent plane from disintegrating, but like you said integration thinking is gone and now we have those individual components that sure look homicidal from outside.
The other issue is that regulators are missing in action or worse. It’s no way to run the industry by relying on concerned youtubers..
How difficult is that?
From the video, the 39 second figure is for the cockpit if the pilots don't get their masks on in time. The passenger cabin would be uncomfortable but wouldn't (or just didn't in that case) reach lethal levels given the volume.
> They even think someone has died from a similar fuming event back in December…
https://en.wikipedia.org/wiki/Swiss_International_Air_Lines_...
I wonder if they just need formaldehyde sensors in the bleed air line...
As far as I understand, the people in the cabin or the cockpit will breath the oil that's now been aerosolized -- in the cockpit it's really hazardous because it's such a small air volume. The oil's full of all kinds of things you wouldn't ever want to breathe in, and in the cockpit it's enough to poison you really fast.
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 sources for that claim, but didn’t show them (or maybe I didn’t watch the video carefully enough), but I wasn’t convinced that it’s actually true.
But if not, It’s possible the FAA/Boeing have better data or other reasoning that makes them sure that the smoke is not that dangerous. In which case their inaction (but not necessarily their PR strategy...) seems more justifiable.