Lion Air crash: Jakarta Boeing 737 'had prior instrument error'

[james_s]

It seems to me they're going to end up needing additional training no matter what. Especially if these two accidents turn out to be caused by MCAS malfunctions, the pilots absolutely need to know what to do in the event that system fails and how to override it.

As far as stick & rudder skills, IMHO knowing how to deal with failures and fly by hand when necessary is exactly the reason we have professional pilots in the cockpit rather than an operator just skilled enough to monitor the automated systems. I worry that too much automation, not just in planes but now in cars too becomes a crutch, enabling people to become complacent and dependent on the technology and unable to step in when the technology inevitably fails in certain edge cases.

[tautech]

Here in NZ pilot skills are assessed as in you're critiqued constantly by one another and have a few trips to the sim each year where assessment jumps to another level.
In the sim you're thrown all sorts of swerve balls and emergency situations that in particular the Captain must master.
Trouble is, if a particular situation is not able to be simulated pilots must refer to their basic flying skills in order to sort it out but if the plane is fighting them thinking it knows better, well Houston, we have a problem.

[ogden]

MCAS was designed to keep pilots from ever experiencing the instability of a MAX at extreme AOA.

It was introduced for a reason - due to forward & up engine placement of MAX (compared to older models) which cause an upward pitching moment that leads to increased AOA and risk of stall. Some facts regarding Flight 302 are interesting: plane crashed with MCAS in "full nosedive mode", yet during last moments of flight plane gained altitude and speed according to flightradar24 data. Pilots have option to disengage automatic stabilizer trim and crank it mechanically using wheel, but seems that instead of taking control over MCAS, they simply fought it - continued to climb at full(?) throttle, reached high speeds with stabilizer in nosedive position and lost control over plane. [all this just speculation of armchair investigator]

[Marco]

Pilots have option to disengage automatic stabilizer trim

An option they didn't think was relevant with the autopilot turned off.

[djacobow]

Pilots have option to disengage automatic stabilizer trim

An option they didn't think was relevant with the autopilot turned off.

I don't think that's true. The trim wheels are moving by themselves. They are large and very obvious when turning. They also make a loud clacking. That is it dead obvious that the machine is retrimming the stab. You might not know why it is happening, but you know that it is. And the procedure to make it stop no matter the reason is simple. You don't need to know what subsystem is commanding the stab trim to disable it.

If the pilots wanted to disconnect the trim motors, they could have easily. That they didn't is a mystery that the CVRs will hopefully reveal. But I suspect the reason was that they weren't completely sure the machine didn't have a good reason to do what it was doing. They're trained to avoid stalls, and if the machine is saying down, down, down, you have to be really confident you know better to disconnect it entirely.

[Marco]

If the pilots wanted to disconnect the trim motors

That's a different switch though, the autopilot trim switch was in their mind irrelevant.

[mtdoc]

Prediction:  The 737 Max will not fly again.

[james_s]

I would bet it will be back in the air within a few months. Worst case they remove MCAS and re-certify, there appears to be nothing inherently wrong with the aircraft, it just handles a bit differently than the 737 classic. The DC-10 had teething problems that included several deadly crashes within a short period and went on to become a successful aircraft, along wit the MD-11 that evolved from it.

[GeorgeOfTheJungle]

I would bet it will be back in the air within a few months. Worst case they remove MCAS and re-certify, there appears to be nothing inherently wrong with the aircraft

Problem is that it seems it is unstable and thats the reason for developing the MCAS.
As for the software update it doesn't matter what Boeing comes up with, it will be under harsh scrutiny of pilots, regulatory agencies and airlines worldwide. It may even make its way to Stackoverflow for discussion who knows .

It's not unstable, the only problem is the bug in MCAS that makes it push nose down relentlessly for no reason and crash, but not the dynamics of the plane.

[GeorgeOfTheJungle]

Prediction:  The 737 Max will not fly again.

But that would be game over for Boeing...

[Kjelt]

But that would be game over for Boeing... 

or the government would have to bail them out from US taxpayers money because it is an to important industry to loose like they did with some banks (so far for capitalism and each should hold up its own).

[tooki]

Prediction:  The 737 Max will not fly again.

There’s a precisely zero percent chance of this outcome.

[Kjelt]

Prediction:  The 737 Max will not fly again.

There’s a precisely zero percent chance of this outcome.

I would not be so sure.
The reputation of the name "737 Max" is already pretty much destroyed.
They might do some small alterations and rename the model to for instance 737 Plus or something like that, in that case mtdoc's prediction has become reality.

[Brumby]

Prediction:  The 737 Max will not fly again.

There’s a precisely zero percent chance of this outcome.

I agree.

I would not be so sure.
The reputation of the name "737 Max" is already pretty much destroyed.
They might do some small alterations and rename the model to for instance 737 Plus or something like that, in that case mtdoc's prediction has become reality.

That could always be a possibility - but I doubt it will go that far.  If Boeing bury the problem name and re-badge the airframe, it is going to be patently obvious as an attempt to hide the embarrassment.  I believe they need to brace themselves and take the flak head on - and I think it is clear they are going to cop some.

[Kjelt]

It is going to be interesting to see the "game" commence, who is going to resign, who is fired, who is getting the blame.
But in the end Airbus survived their computer-erroneous crashes, so I do not see why Boeing would be different.

[FrankBuss]

Some rumors about the audio recordings and flight data records:

https://www.reuters.com/article/us-indonesia-crash-exclusive/exclusive-cockpit-voice-recorder-of-doomed-lion-air-jet-depicts-pilots-frantic-search-for-fix-sources-idUSKCN1R10FB

In short: Looks like the nose was pushed down by the trim system and they didn't recognize it, and needed too long to read the manual how to fix it. The evening before another crew had the same problem, but they knew how to fix it, but apparently didn't tell the new crew about the problem.

Isn't there some regulation to report all problems, and for the new crew to read all reports? When I'm watching bus driver changing, they always ask and tell each other if there is a problem with the bus or on the route. I would have thought that's even more verbose for planes.

[GeorgeOfTheJungle]

No doubt, the pilots are to blame too. After the 610 flight crash they should have known better and disable the damn thing at the first sign.

[ogden]

It's not unstable, the only problem is the bug in MCAS that makes it push nose down relentlessly for no reason and crash, but not the dynamics of the plane.

I beg to differ, The software was designed to compensate for a new instability that resulted from some small physical-design modification and MCAS was added to comply with airworthiness certification

Exactly. Pushing nose down to decrease AOA and avoid stall is function of MCAS, not bug. Main question here is: it was bad decision of MCAS due to faulty AOA sensor or bad decision of pilots to fight MCAS or maybe both. If instruments scream that stall is imminent, plane itself is pushing nose down to decrease AOA but you gain altitude and speed instead (thus increase AOA) - it is very strange thing to do to say it politely.

[edit] Who the hell runs life-critical system from input of just two sensors single sensor?! - Even automobile airbags have better redundancy (AFAIK).

[Kjelt]

[LapTop006]

The reputation of the name "737 Max" is already pretty much destroyed.

Nah. You'd still fly on a 787 despite the battery fires?

The 777 with engine icing?

What about a DC10 (ok, the final ones are now out of passenger service) after all the cargo door incidents?

The earlier 737s with rudder hard-over?

These things happen with new models, and are usually fixed.

As others have said, the 737MAX is a bit of a hack to keep the line going to compete with the re-engined A320 series, Boeing's plan was to do a fresh design so they could throw away a bunch of the legacy the 737 type certificate, but they decided that would give them a risk of losing customer to Airbus.

Their big hope in this space is probably the MOM airplane plan goes very well, enough to justify a shrink variant that would fit in 737 gates and share a type certificate (similar to the 757/767 days).

[Bud]

Both planes crashed in presumably hot climate. Could that have to do with the angle of attack sensors failing?

[MT]

https://www.bloomberg.com/news/articles/2019-03-19/how-an-extra-man-in-cockpit-saved-a-737-max-that-later-crashed

As the Lion Air crew fought to control their diving Boeing Co. 737 Max 8, they got help from an unexpected source: an off-duty pilot who happened to be riding in the cockpit.

That extra pilot, who was seated in the cockpit jumpseat, correctly diagnosed the problem and told the crew how to disable a malfunctioning flight-control system and save the plane, according to two people familiar with Indonesia’s investigation.

The next day, under command of a different crew facing what investigators said was an identical malfunction, the jetliner crashed into the Java Sea killing all 189 aboard.

The presence of a third pilot in the cockpit wasn’t contained in Indonesia’s National Transportation Safety Committee’s Nov. 28 report on the crash and hasn’t previously been reported.

[daddylonglegs]

Prediction:  The 737 Max will not fly again.

In the early 90s a design flaw in 737s caused at least two fatal crashes (0) and yet here we are.

Having said that, this time round things might be different. The FAA is seen to be compromised (1):

As Boeing hustled in 2015 to catch up to Airbus and certify its new 737 MAX, Federal Aviation Administration (FAA) managers pushed the agency’s safety engineers to delegate safety assessments to Boeing itself, and to speedily approve the resulting analysis.

But the original safety analysis that Boeing delivered to the FAA for a new flight control system on the MAX — a report used to certify the plane as safe to fly — had several crucial flaws.

Other agencies will not accept the FAA's certification of the software modification which will cause some delays in the return to flight. The agencies may also reject the FAA's original certification of the 737 MAX and require Boeing to go directly to them for certification (2). If so it will be months or years before the 737 MAX flies in those areas, though it will probably return to flight in the US in a few months.

I recommend reading the Seattle Times article (1). It is hair-raising and what they describe might explain how Boeing chose to activate MCAS off a single sensor even though the why mystifies everyone they asked.

An older article in the same paper (3) discuses the fact that the symptoms of MCAS activation are different to previous runaway trim failures and how this might have flumoxed the Lion Air pilots, both on the accident flight and on the previous flight. That previous flight didn't crash but the pilots were unable to diagnose what was wrong and why what they did worked.

Of course, at this stage we don't know what happened in the second crash and the final verdict is not yet in on the first. The pilots on the Ethiopian flight had information not available to the pilots on the Lion flight.

(0) https://en.wikipedia.org/wiki/Boeing_737_rudder_issues

(1) https://www.seattletimes.com/business/boeing-aerospace/failed-certification-faa-missed-safety-issues-in-the-737-max-system-implicated-in-the-lion-air-crash/

(2) https://globalnews.ca/news/5072383/canada-eu-reviewing-certification-boeing-737-max/

(3) https://www.seattletimes.com/business/boeing-aerospace/faa-evaluates-a-potential-design-flaw-on-boeings-737-max-after-lion-air-crash/

Edit: Apologies, KL27x already posted a link to the main article I was citing.

[MT]

Mmkaay, now FBI with special counsel Miiuulleeerr and DOJ is setting up a investigation to Russian collusion as they suspect Piutin has caused the MCAS software bug. 2 years later no collusion was found and Miiuulleer refuses to release clown report while Dumpf having tea and cakes with Boing CEO..

I like my tinfoil hats, so fair enough. But wait and see. FAA was fasttracking these approvals because someone was poking/pressuring them and or there was some major personal interest or incentive. Maybe Boeing hires retired FAA officials as consultants, and that is enough. Maybe there's more inbreeding and impropriety than that, even. I imagine Boeing is a very important company to our country's military and government.* And somehow many people were actively not doing their jobs and looking the other way.

*Transportation Secretary Elaine Chao even rode in a 737 MAX two days after the latest crash.

I also like my personal tinfoil hats but that was perhaps not the point, but yes wait and see, but perhaps its more like its to much moo money involved (as usually) to send anyone of the "elite" to jail........................except for that little scape goatee engineer somewhere deep down Titanics boiler room?

Secretary Elaine Chao is more of the symptom of US gov mad cow disease rather then the cure. She was plain luckey!

[iMo]

...
The next day, under command of a different crew facing what investigators said was an identical malfunction, the jetliner crashed into the Java Sea killing all 189 aboard.

I can hardly imagine why the crew N1 with such an issues during the flight had not informed the crew N2 on it.
Just watching CNN on new developments on Lion Air case - the pilots were searching in the flight manuals during the dive (from CVR).