Slashdot Mirror
Boeing 737 Max Jets Grounded By FAA Emergency Order (nbcnews.com)
President Trump announced an emergency order from the Federal Aviation Administration on Wednesday grounding Boeing 737 Max jets in the wake of an Ethiopian Airlines crash Sunday and a Lion Air accident in October that together killed 346 people. The emergency order comes two days after the FAA said the Boeing 737 Max planes are still airworthy. NBC News reports: Trump's announcement came as the FAA faced mounting pressure from aviation advocates and others to ban flights of the planes pending the completion of investigations into the deadly accidents. Sunday's crash killed 157 people and the one in Indonesia in October left 189 dead. "We're going to be issuing an emergency order of prohibition to ground all flights of the 737 Max 8 and the 737 Max 9 and planes associated with that line," Trump announced, referring to "new information and physical evidence that we've received" in addition to some complaints.
The FAA said it decided to ground the jets after it found that the Ethiopian Airlines aircraft that crashed had a flight pattern very similar to the Lion Air flight. "It became clear that the track of the Ethiopian flight behaved very similarly to the Lion Air flight," said Steven Gottlieb, deputy director of accident investigations for the FAA. United States airports and airlines reacted to the order Wednesday, acknowledging that it will lead to canceled flights. American has roughly 85 flights a day on the Boeing Max 8 and Max 9 jets. United Airlines has about 40 such flights. Southwest Airlines has the most, about 150 flights per day on these types of jets out of the airline's total of about 4,100 flights daily.
The FAA said it decided to ground the jets after it found that the Ethiopian Airlines aircraft that crashed had a flight pattern very similar to the Lion Air flight. "It became clear that the track of the Ethiopian flight behaved very similarly to the Lion Air flight," said Steven Gottlieb, deputy director of accident investigations for the FAA. United States airports and airlines reacted to the order Wednesday, acknowledging that it will lead to canceled flights. American has roughly 85 flights a day on the Boeing Max 8 and Max 9 jets. United Airlines has about 40 such flights. Southwest Airlines has the most, about 150 flights per day on these types of jets out of the airline's total of about 4,100 flights daily.
Except they could still fly all over USA.
When the announcement was made there were 10 of these planes in the air.
Claims it was collusion with the Russians and Trump was paid in Aeroflot stock.
It's a critical safety system, required to obtain flight certification because of the larger, more powerful engines.
Without it, on full throttle, the aircraft doesn't have enough authority to bring the nose down once it goes up too high.
That's why only the MAX variants have this system, because they have larger engines.
It has nothing to do with auto-pilot, except the system is disabled when auto-pilot is engaged.
While you can compensate for a poor design in software, the best way is to not make the poor design in the first place.
There is a 'neutral' point for the engines to be located such that a large amount of thrust causes the body to remain mostly neutral.
It's a critical safety system, required to obtain flight certification because of the larger, more powerful engines.
Without it, on full throttle, the aircraft doesn't have enough authority to bring the nose down once it goes up too high.
I don't suppose you have any citations for any of that? If it's actually true it's certainly significant, but I've seen zero evidence of that anywhere. All the documentation talks about it being designed to assist pilots avoid a stall under very specific conditions; absolutely nothing anywhere says that its safety critical, or that the aircraft cannot be controlled at some point prior to stall.
I posted this 5 months ago: Reasons Boeing CEO Dennis Muilenburg should be replaced.
And it's only been in service since May 22, 2017.
Considering the extreme safety of air traffic in general that's one freakishly unsafe plane.
It makes me glad I'm not the engineer/developer responsible for building that subsystem.
I stole this Sig
A clean-sheet design would absolutely have better positioning of the engines. Unfortunately, the 737 platform comes from an era of much smaller engines, so there just isn't enough under-wing clearance to fit modern turbines in the original locations (even versions with engine updates from 10-20 years ago have odd bulges around the nacelle where parts had to be relocated to fit).
The MCAS system was implemented because the 737-MAX engines are placed more forward of the wing which will tend to induce a nose up pitching moment particularly at high angles of attack near stall. This would've probably been a certification issue.
Now the 737 MAX had the engines placed so far forward to enable enough ground clearance. The original 50-year old 737 had low bypass engines which much smaller and could be placed directly under the wings. The newer models already ran into ground clearance issues, and this was initially solved by putting the engine systems to the side of the engine creating a distinct ovoid nacelle shape. With the new GE Leap engines, this fix was no longer sufficient due to larger engine diameter, hence the repositioning forward.
Newer aircraft like the airbus a300 series and the airbus a220 (bombardier cseries) never had this issue because they were designed to accomodate large diameter newer generation engines. The basic design of the 737 has always suffered from this flaw and really Boeing should have invested in a new aircraft design rather than try to re-engine an aircraft that was never designed for it. This was like fitting a V-12 engine into a model T.
Sad to see the once-proud remnant of American industrial might, Boeing, brought low like this. I thought Airbus lost it on Air France 447 when the pilot pulled his sidestick all the way back and kept it there until the plane crashed. On a Boeing, the dual control sticks would have revealed this and lives would have been saved. But now, we have this:
"One high-ranking Boeing official said the company had decided against disclosing more details to cockpit crews due to concerns about inundating average pilots with too much information â" and significantly more technical data â" than they needed or could digest."
So they:
1) Design an aircraft that has an inherent tendency to pitch up
2) Implement an a system to persistently add control inputs during critical phases of flight
3) Do NOT disclose system description to pilots in FCOM
How about fundamental rules:
Understanding what automation systems do.
Control the automated systems according to strong pilot skills.
Shutting down free speech with violence isn't fighting fascism. It IS fascism!
The A320 series had the ground clearance necessary to accomodate the new engines without needing to reposition them, hence no stability issues due to the engine placement that might have required an equivalent MCAS system.
The MCAS system was implemented because the 737-MAX engines are placed more forward of the wing which will tend to induce a nose up pitching moment particularly at high angles of attack near stall. This would've probably been a certification issue.
It would have been a certification issue because it changes the handling characteristics of the aircraft, not because it's inherently unsafe. The MCAS is meant to automatically counter the changes so that the aircrew can fly the aircraft the same way they would a legacy 737. It has to do with Boeing being able to sell the aircraft without excessive certification requirements for pilots, rather than anything to do with safety.
This was like fitting a V-12 engine into a model T.
That's a horrible comparison. The fact that the engines are more powerful has nothing to do with anything. The placement and shape of the engine cowlings is the issue.
He just had to do it. I'm a dictator Donnie made the completely authoritarian decision to ground them.
And had he not done so, he would be a corporate stooge endangering innocent life.
Boeing considered raising the landing gear, but considered it too costly as it meant changes to the centre wing box and associated structure, so they bodged it with an engine higher on the wing and software to compensate for the negative handling characteristics. And then they didnt tell anyone who actually flew the aircraft...
Because it would cost too much - the MAX series was Boeing *reacting* to Airbuses launch of the A320NEO family. Boeing had had a study ongoing for years about launching a clean sheet 737 replacement, and were going down that road for introducing in the mid 2020s, but then Airbus launched the NEO and airlines started their fleet renewal processes as a result.
Boeing was caught so off guard that, when a customer no one thought would ever buy Airbus again (due to bad blood after a crash - AA wanted Airbus to take all the blame, Airbus said nope, your pilots were to blame, AA didn't place another order with Airbus as a result) placed an order for the NEO and split it by also placing an order with Boeing, they ordered "130 Airbus A320NEO aircraft AND 130 Boeing aircraft (whatever Boeing comes up with as a 737 replacement)"...
Make no mistake, the MAX is a reaction - otherwise they would have lost a lot more of the market than they already did by the procrastination they did over the A320NEO launch.
The NTSB came to its own conclusions regarding its investigation (they blamed both, but primarily the airlines training), but AA wanted Airbus to pay all the compensation and costs of the crash, as well as publicly assuming responsibility, so as to preserve AAs reputation.
From this.
There is a 'neutral' point for the engines to be located such that a large amount of thrust causes the body to remain mostly neutral.
Yup, and that's how the other versions are configured. These new MAX configs have physically larger engines, so - to prevent have to redesign the whole aircraft to deal with them - the engines are positioned a little bit further forward, and a centre of the engine a little bit higher off the ground (ie closer to the wing). The centre of thrust is consequently moved forward and up in relation to the centre of gravity. The result is the craft will nose-up under full throttle.
The other problem is that companies were assured pilots would not need training in the new system, however a critical difference between this system and normal auto-pilot systems is that this system does not turn off when pilots attempt an overide.
Seriously, what the *bleep* does this kind of corporate malfeasance have to do with Millennials? You do know this kind of crap existed before Millennials, right?
Hi! I make Firefox Plug-ins. Check 'em out @ https://addons.mozilla.org/en-US/firefox/addon/youtube-mp3-podcaster/
Pax? Is that the latest /. AC lingo?
It's the standard aviation industry term for passenger.
Presumably, the term is a an abbreviation for "Paxed in like sardines".
The problem in the crashed flights is that it happened at a time when the pilots are fairly busy anyway and they didn't realize what was happening.
Not really. The first time it happened for Lion Air was as they approached 2,000 feet and went flaps up. Not a particularly busy time, but it did catch them off guard and they lost about 400 feet altitude. They, for whatever reason, then decided to drop the flaps again ... which fixed the issue since MCAS doesn't operate with flaps down. They continued to climb to about 5,000 feet at which point they went flaps up again.
From that point on they were struggling with it for something like 8 minutes, but maintaining altitude the entire time. It's mind boggling that they didn't think to either drop the flaps again, or to go to their runaway trim checklist. They continued to fight it until shortly before the end, at which point the black box makes it look like they just gave up and plumeted out of the sky.
tl;dr: "busy" had nothing to do with it.
I'm not a pilot but I wonder if the better approach wouldn't have been to just recommend turning it off before they even take off.
Not really, unless there's a lot more wrong with the system than we currently know. It does actually make the aircraft easier to fly without needing conversion training, and it does help prevent stalls. Pilots just need to follow their checklist if it acts up.
According to Boeing, it's just meant to make the plane handle more like the non-MAX version of the 737.
Yep, that's the gist of it.
I would argue that either the pilot can recognize whether the plane is about to stall and ignore the AOA sensor entirely, in which case both sensors are non-essential, or the pilot can't, in which case the pilot also can't reliably determine which sensor is wrong. More importantly, if the pilot can, then the avionics systems should be able to do so as well. And if not, then that single backup is only useful when the sensor fails outright (e.g. no output, wiring fault, etc.).
And in this case, because the plane makes critical decisions that impact the airworthiness of the aircraft in response to that data and apparently cannot determine which AOA sensor is lying, having only two AOA sensors just means that the risk of the entire system failing because of incorrect data is twice as high as if it had only one AOA sensor. Assuming it is practical to fly the plane with both stall warnings and MCAS disabled, then everyone would arguably be better off if the aircraft had only a single AOA sensor, statistically speaking. If that were the case, we'd have probably had only one crash in the first two years, instead of two (not that such numbers would be good, mind you, just less appalling).
IMO, having too little redundancy can actually be worse than not having any at all. It seems likely that this aircraft, as designed, cannot be made safe unless Boeing adds either a second pair of independent AOA sensors or a couple of Pitot tubes as backups for resolving disagreements. Two sensors clearly isn't enough, given their apparent propensity for failure at low altitudes.
Check out my sci-fi/humor trilogy at PatriotsBooks.
No people under the jurisdiction of the FAA have died in those two crashes. Incase you are unaware, the FAA is an American agency, and only has control over US skies, and US bound flights.
The FAA pays attention to world wide flight data and bases some decisions on what it sees there. The Lion and Ethiopian crashes we're under the jurisdiction of the counties in which they originated from and crashed.
Similarly, China has its own agency too, and that agency grounded the planes well in advance of when the FAA did.
Do you guys know who the director of the Federal Aviation Authority is right now? Nobody does, because Trump has never gotten around to appointing one. To be fair, he's been very busy with the golf co-championship and everything, and it probably just slipped his mind.
Nothing matters any more.
You are welcome on my lawn.
You're kinda right but you're missing the purpose of dual sensors. If you want true redundancy you would obviously want 3 or more sensors. When you install 2 sensors, you're not looking for one to be a backup for the other; rather you're looking for them to check each other. If they disagree then you know that the system as a whole is no longer trustworthy, and you can throw signals at the aircrew to let them know not to depend on the readings.
Now, as that relates to MCAS, Boeing had two options in the case of sensor disagreement:
1. Go with the best-case sensor reading, in which case you will likely not react to an actual stall condition.
2. Go with the worst case reading, in which case you may react to a condition which isn't actually a stall.
3. Ignore them completely, in which case the MCAS system becomes inoperative and can't prevent a stall.
They decided to go with the worst case reading because, generally speaking, stalls are bad. You want to prevent them as much as possible. Going nose down when you don't need to is also bad, but not nearly AS bad unless you happen to be close to the ground .... and they tried to make sure that wouldn't happen by disabling the system when the flaps are down. Even if you are at a relatively low altitude with the flaps up for some reason, a stall is typically worse than going nose down because a stall requires significant altitude to recover from.
It was a rational design choice. Where they probably erred the most was in not telling pilots about it. I'm not sure that it would have made a difference to that Lion Air crew even if they had been told, but they still should have been informed.
It's also worth noting that, at least if the folks on PPRuNe are correct, and assuming I'm understanding correctly, even though the aircraft itself has two AOA sensors, the MCAS system only uses one of them, which is to say that if they disagree, it has no idea.
Worse, from what I've read, this aircraft in its default configuration lacks the extra AoA gauges to independently show the output of the two AoA sensors to tell you that the MCAS system is getting crap data, instead providing only an AoA Disagree light. And apparently, a few don't even have that (WTF?).
It sounds to me like there are multiple aspects of the way the MCAS system was designed that are seriously flawed, any one of which should have resulted in it not being certified to fly. But the most serious of those, assuming I understand correctly, is that this system effectively has no redundancy at all, yet is in a position to seriously wreck the airworthiness of the aircraft.
Check out my sci-fi/humor trilogy at PatriotsBooks.
More accurately, Dick Donnie saw FOX reporting other countries grounding the planes. At first, he thinks that would be bad for American business and after that nice CEO from Boeing gave him a ringy-dingy to pump his ego. However, aides were also watching and realized the danger that Dick Donnie would be in were one of those planes go down in America while the the FAA hadn't grounded the planes. He'd be blamed. It was unconscionable that he could be blamed, after all he is a genius. So he mouths off in a statement to the press including the bit about planes becoming too complicated for pilots...not for him, of course, he is a genius.
Meanwhile, over at the FAA and the Dept. of Transportation where Madame Chao, Mitch McConnell's wife, had been supporting the previous policy of "those crazy foreigners and their grounding OUR American planes", they get wind of Dick's pronouncement and immediately issue their own press release that claimed with consultation with Canada, they had heroically decided to ground the planes. Dick's ego is preserved, all is well.
If by "chaotic mismanagement of the grounding" you mean, "waited until there was evidence to make a decision affecting safety" then sure. Exactly 0 incident occurred between the time of the crash in Africa and the grounding of the aircraft in the USA. Seems they acted rationally to wait for evidence before grounding aircraft out of media fear...
Yes it's an anecdote! Were you expecting original research in a Slashdot comment?
so they bodged it
You mean made a design decision?
And then they didnt tell anyone who actually flew the aircraft...
Less hyperbole please. Not only are the changes to the design known by pilots, they are known by the frigging public.
And the aircraft as a whole are airworthy. The Lion Air aircraft was not airworthy because it had not been repaired. That's a maintenance failure, which led to a crash when combined with pilot error. There's nothing in that crash to indicate that the MAX as a fleet are not airworthy. There may be something about this second crash which eventually leads to that conclusion, but at this point it's all just speculation.