Ed 737 Max Crashes (was Shutdown caused Boeing crash.)

[smartcooky]

So far it seems like Boeing and their customers caused the crash, with the shutdown having nothing to do with it.

Raise your hand if you still like the thread title.

If the shutdown caused delays in FAA certification for this system, that otherwise would have taken place and resulted in avoiding this accident, then I still like the thread title.

If the delays to FAA certification are not implicated in possible corrective action that might have saved this aircraft and its passengers, then I think the thread title is at best, misleading.

If Boeing were not even doing anything to certify MCAS, or the FAA certification didn't cover it, then the thread title is wrong and should be changed.

I'm sorry that I can't give you the nice, clean, bright line (the one where everything on one side is black, and everything on the other side is white) that you are looking for.

 

[theprestige]

If the shutdown caused delays in FAA certification for this system, that otherwise would have taken place and resulted in avoiding this accident, then I still like the thread title.

If there was no FAA certification, how do you excuse Boeing selling the plane, and airlines operating it?

 

[Ziggurat]

Hmm. I'm not 100% sure this means the airline did anything wrong as such. The incident when the off-duty pilot saved the day only happened the day before.

Those pilots would have no idea that is was a systemic problem.

I don't think that makes any difference. Let's assume they thought that it was a problem specific to that plane^*.

They should still have figured out a solution for that plane, or at least told any pilots flying it after them what the previous pilots experienced and how they handled it in case it happens again, which it did.

They didn't do so. And that pane crashed as a result.

*and it a sense it was: the crash seems to need a combination of the new MCAS, pilots who didn't know how to handle it, and a sensor error to make MCAS behave badly. The first two problems are systemic, but the last one isn't.

 

[smartcooky]

I don't think that makes any difference. Let's assume they thought that it was a problem specific to that plane^*.

They should still have figured out a solution for that plane, or at least told any pilots flying it after them what the previous pilots experienced and how they handled it in case it happens again, which it did.

They didn't do so. And that pane crashed as a result.

*and it a sense it was: the crash seems to need a combination of the new MCAS, pilots who didn't know how to handle it, and a sensor error to make MCAS behave badly. The first two problems are systemic, but the last one isn't.

Its not clear that they are the same planes... the article you linked contradicts itself on that matter.

Lion Air have/had ten 737 max 8's. The one that crashed was PK-LQP.

AIUI, the one that had this incident was PK-LQK, a different aircraft

Belay that. It was the same aircraft. Not only that, but the night before, the crash flight, this same aircraft has a number of problems, including a burning smell in the cabin, and and a sudden loss 200 feet of altitude in just a few seconds.

If all this is true, then you're right, that is a serious problem for Lion Air.

Nonetheless, Boeing are still responsible for putting into an aircraft a new, automated system that is designed to take control away from the pilots, without any documentation in either the QRH or the FCOM. That alone is unprecedented, and unacceptable.

 

[theprestige]

Its not clear that they are the same planes... the article you linked contradicts itself on that matter.

Lion Air have/had ten 737 max 8's. The one that crashed was PK-LQP.

AIUI, the one that had this incident was PK-LQK, a different aircraft

It's possible the airline said, "the problem was reported on *this* 737-MAX; no reason to warn the pilots of *that* 737-MAX". In that case, I'd want the left thumbs of everyone involved in that decision, yakuza style.

 

[a_unique_person]

It's possible the airline said, "the problem was reported on *this* 737-MAX; no reason to warn the pilots of *that* 737-MAX". In that case, I'd want the left thumbs of everyone involved in that decision, yakuza style.

Why would they think it was a general rather than a specific problem?

 

[Drewbot]

Belay that. It was the same aircraft. Not only that, but the night before, the crash flight, this same aircraft has a number of problems, including a burning smell in the cabin, and and a sudden loss 200 feet of altitude in just a few seconds.

If all this is true, then you're right, that is a serious problem for Lion Air.

It is made even more serious, in that some pilots clearly knew how to override the MCAS system. On the Lion Air plane, the day before the crash, an extra pilot riding in the cockpit saved the very same plane from crashing. Why that plane wasn't grounded immediately, isn't understood by me.

https://www.cnn.com/2019/03/20/asia/lion-air-third-pilot-intl/index.html

Investigators said the jet experienced problems on its last four flights -- including, crucially, the flight that crashed, according to Tjahjono.

 

[JoeMorgue]

It is made even more serious, in that some pilots clearly knew how to override the MCAS system. On the Lion Air plane, the day before the crash, an extra pilot riding in the cockpit saved the very same plane from crashing. Why that plane wasn't grounded immediately, isn't understood by me.

Well maybe the Boeing people were just tired, did you ever think of that?

 

[theprestige]

Why would they think it was a general rather than a specific problem?

Because the pilot that solved it did so using general knowledge of the type. Also because considering and accounting for that possibility should have been an automatic and immediate response to the incident.

 

[ponderingturtle]

How about viewing these crashes as a victory for deregulation of industry making it better and more efficient?

https://slate.com/news-and-politics/2019/03/boeing-737-max-crash-faa-regulations.html

" For the past decade, the FAA has embraced a policy of letting aircraft manufacturers like Boeing self-certify that their systems meet safety requirements. According to Seattle Times aerospace reporter Dominic Gates, the FAA delegated the certification of the 737 Max’s MCAS system to Boeing itself. The company’s own engineers, “authorized to work on behalf of the FAA,” conducted the safety analysis of the system, Gates writes, and “concluded that the system complied with all applicable FAA regulations.”"

 

[Fast Eddie B]

Of course, we must critically examine the system that allowed apparent fatal flaws in design to sneak through.

However, this can also be seen as an example of “the exception proves the rule”.

Over the last decade, millions upon millions of miles have been flown by US carriers, most years without a single fatal accident. Making airline flying one of the statistically safest things one can do. And that’s all with existing procedures in place.

I think to take these two recent failures of the overall system as endemic is a case of “hasty generalization.” But we must ferret out the specific cause(s) of these specific crashes, and if they do point out a fundamental flaw in the safety systems we depend on to keep airline travel safe we must address that flaw or flaws. But the system we have in place has been pretty darn successful over the years, and that should be recognized - and applauded.

 

[ponderingturtle]

Of course, we must critically examine the system that allowed apparent fatal flaws in design to sneak through.

However, this can also be seen as an example of “the exception proves the rule”.

Over the last decade, millions upon millions of miles have been flown by US carriers, most years without a single fatal accident. Making airline flying one of the statistically safest things one can do. And that’s all with existing procedures in place.

I think to take these two recent failures of the overall system as endemic is a case of “hasty generalization.” But we must ferret out the specific cause(s) of these specific crashes, and if they do point out a fundamental flaw in the safety systems we depend on to keep airline travel safe we must address that flaw or flaws. But the system we have in place has been pretty darn successful over the years, and that should be recognized - and applauded.

And we have been breaking it down with things like self certification from the manufacturer. In a way like with vaccines it is a victim of its own success, and people forget why the regulations exist in the first place.

Would the FAA have certified this plane to fly? Good that they aren't needed anymore I guess. We know manufacturers don't really care be they Boeing or GM, they are happy to have customers die as long as it does not result in bad press.

 

[beachnut]

I pretty much go along with most of this and the excerpt you posted, except this bit.

"Even if the pilots disconnected the trim system (as per Boeing 'fix'...) its likely to be left in a nose heavy trim position... which takes time to fix... "

Not if I understand MCAS functionality correctly.

Switching off the stab trim does not disconnect the trim and leave the elevator in a fixed position, it turns off the autopilot inputs to the trim system. This means the trim system is returned to manual control, and the pilot is no longer fighting against the autopilot.

Have not finished research... It appears you could stop this by cutting off the stab trim to the autopilot.

Does that mean the electric trim on the pilots yoke works when you cut out the stab trim switch? I think it might, and you could just trim the stab and the MCAS would have to catch back up, you could play cat and mouse with the failed system if you were in 'test pilot' mode.

When we had runaway trim, we cut out the trim, and lost electric trim. Or you could stop the trim runaway by using the trim on the yoke in the opposite direction while you cutoff the trim on the console.


I have to catch up, by researching the questions I have: were the pilots had flying vs. the autopilot flying the departure (I always hand flew departures and approaches in the KC-135, an old plane with fly by wire, aka wires directly connected to the control surfaces with some help with hydraulic assist to the rudder which could be cut off, and hydraulic spoilers, which could be cutoff.

If I flew the 737 Max, all I need to know is how to stop the failed input, what switch and action do I take.

In the KC-135 our electric trim was very fast, if you accidently hit the trim down, the plane would pitch over knock off the generators and you have 6 seconds or less to recover. The trim was fast because of our refueling mission, and also comes in handy when a C-5 or large aircraft is in the contact position, we need to trim for the bow-wave effect.

Our cars are starting to do stuff automatically, like stop the car from backing up, or moving.


Too many questions I have not looked up for answers.
Did they flight test the new pitching moment of the engines without modification to the flight controls? Was it more than the pilots could handle? It does not make sense to add active measures without thinking about the failure modes. Makes me wonder if they had enough pilot who are engineers in on the design, or did some engineer add a fix without oversight.

I hate flying Airbus, they always seem to pitch over at leveloff vs a smooth power slight trim adjustment any pilot could make for passenger/crew comfort.

How did Airbus fix the take, oops, autopilot wants to land and crash problem.

I would disconnect the autopilot, and it appears you would have to know to hit the cutoff (turn off) the stab trim for the autopilot. If my trim was moving without my input, I would be upset, and run it opposite at a minimum, which might of saved both flight if that was the problem.

We had simulators rides which constataly had runaway trim and other emergency. It became nearly and instant reaction to stop runaway trim, and it was why you have a pilot, to take care of emergencies.

Both crews must of been clueless that the MCAS was trimming slowly nose down until they lost elevator authority and nose dived into the ground with MCAS trimming all the time nose down - something I assume shows up on the TRIM-Wheel right next to them, something that should be in their cross check even if they have no clue What MCAS was.

 

[Pope130]

We had simulators rides which constataly had runaway trim and other emergency. It became nearly and instant reaction to stop runaway trim, and it was why you have a pilot, to take care of emergencies.

Both crews must of been clueless that the MCAS was trimming slowly nose down until they lost elevator authority and nose dived into the ground with MCAS trimming all the time nose down - something I assume shows up on the TRIM-Wheel right next to them, something that should be in their cross check even if they have no clue What MCAS was.

I can verify what beechnut is saying here. I was a simulator operator at Castle AFB (SACs training base for the B-52 and KC-135) for over ten years. I'm one of those guys who gave the pilots a bad time, professionally. A regular part of almost every emergency procedures mission was 'runaway stab trim'.

The center console layout of the 737 is much like the 135. The stab trim wheel, quadrant and cutout switches are apparent, and easily accessible. It should have been quite obvious that the trim was running, and, regardless of the cause of the runaway, the emergency procedures have not changed in fifty years.

 

[smartcooky]

https://www.bbc.com/news/business-47759966

Ethiopian Airlines crash: 'Pitch up, pitch up!'

This is what the pilots were heard saying just prior to the crash.

"Soon after take-off - and just 450ft (137m) above the ground - the aircraft's nose began to pitch down.

One pilot, according to the Wall Street Journal, said to the other "pitch up, pitch up!" before their radio died.

The plane crashed only six minutes into its flight."​

Something isn't right about this. AIUI the MCAS is not supposed to kick in unless the flaps are fully retracted. Typically, in a 737, you don't even start retracting the flaps until about 700 to 800 AGL @ V2 + 15kts, even then, they are only fully retracted at about 1500 AGL

Do I have to say it? If the flaps were still down at 450 AGL, how on earth could the MCAS be pitching the nose down?

IMO, there should be NO system on an aircraft capable of autonomously pitching the nose down only 450 AGL; at the typical climbout rate of 1800 FPM, that is about 15 seconds after V2 rotate. Under those circumstances, its amazing that the flight even lasted as long as six minutes.

 

[a_unique_person]

I can verify what beechnut is saying here. I was a simulator operator at Castle AFB (SACs training base for the B-52 and KC-135) for over ten years. I'm one of those guys who gave the pilots a bad time, professionally. A regular part of almost every emergency procedures mission was 'runaway stab trim'.



The center console layout of the 737 is much like the 135. The stab trim wheel, quadrant and cutout switches are apparent, and easily accessible. It should have been quite obvious that the trim was running, and, regardless of the cause of the runaway, the emergency procedures have not changed in fifty years.

Ianap but I have been reading the posts of various pilots.

The failed AOA sensor is going to give a stall warning with the stick shaker. This will grab the pilots interest first.

The MCAS does not behave like continuous runaway trim, it is intermittent, much like STS.

There are multiple events and alarms going on. A stall warning at the same time as overspeed is going to cause confusion.

They are still in the takeoff phase of the flight when they are going to be busy anyway.

Given the circumstances the possibility of the pilots not getting it right in time, since they are still low to the ground, which they don't have a lot of, is going to be very high.

The MCAS system is half arsed

Only uses one sensor for input.
Can be continually retriggered.

 

[jeremyp]

Not if I understand MCAS functionality correctly.

Switching off the stab trim does not disconnect the trim and leave the elevator in a fixed position,

That's exactly what it does (I assume by "elevator" you mean "horizontal stabiliser"). It cuts power to the electric motor that drives the jackscrew. After that, the only way to move the horizontal stabiliser back is to do it with human brute force through the trim wheels which are mechanically connected to the stabiliser trim system.

Here's a video that explains what it does, the relevant part is from about 13 minutes on

https://youtu.be/xixM_cwSLcQ?t=809

Other points of interest: at 5:20 there is footage of the jackscrew in operation and at 17 minutes a demonstration of runaway trim in the simulator (on a Boeing 737 NG, not a MAX).

You'll note that, returning the trim to a sane setting is not an instantaneous task and it took both pilots working together several seconds to complete the task. If your emergency started at below 1,000 feet, I imagine this would be time critical.

 

[Fast Eddie B]

Would the FAA have certified this plane to fly? Good that they aren't needed anymore I guess.

No one suggested that.

But interestingly, there is a relatively new class of aircraft where the manufacturer is allowed to self-certify that their aircraft meet appropriate standards. The are called Special Light Sport Aircraft. This class was created just over a decade ago and has been pretty successful. The aircraft included are admittedly light weight and can only carry two occupants and have a few other limitations.

This was motivated by the fact that no major manufacturer was providing light training aircraft, and the fleet of existing trainers was getting very, very old.

Of course, we should expect the FAA to be far more involved in certifying commercial aircraft. But I don’t think it’s that unusual for them to do so largely via oversight, vs direct, hands on testing.

Certifying any aircraft is a Herculean task. The joke among pilots is when the weight of the paperwork equals the weight of the plane, it’s ready to fly.

We know manufacturers don't really care be they Boeing or GM, they are happy to have customers die as long as it does not result in bad press.

I think that paints with too broad a brush and is way too cynical. But you’re entitled to your.opinion.

Finally, a linked article posits that the pilots had mere seconds to react. I hear that and I think maybe 10 seconds, max? But 40 seconds would have seemed like a horrifying eternity to those pilots as they continued to wrestle for control over a system they apparently did not fully understand. As I said upthread, high on the list of a pilot’s worst nightmares.

 

[a_unique_person]

Are you sure? Over on SGU someone just put forth that the 737 Max series still uses cables, rods and hydraulics for flight controls.

Or were you excluding the 737 Max as not being “modern”? It’s kind of a hybrid, with very old roots but lots of modern tech tacked on.

This, from Quora: Every newly designed Boeing aircraft since the Boeing 777, which came out in 1995, has fly-by-wire controls. Legacy aircraft which still sell, like the long-in-the-tooth 737, the new version of the 747, and any 767 still being manufactured (for the military or civilian use), are still non-fly-by-wire.

737dates back to '60s technology. They keep fiddling with it but that doesn't make it a modern plane. plenty of old anachronisms are in them that would not be allowed today but were grandfathered in. The lack of emergency slides off the wings, for example.

 

[Giordano]

My apologies if this was already answered up thread:

Did activation of the MCAS nose-down function generate a clear warning to the pilots? An audible alarm ("Anti-stall nose down trim activated"..."Anti-stall nose down trim activated") or something equivalent?

Many of the accounts I've read suggest that the pilots were, at least initially, unaware that the MCAS system had become activated and was operating the stabilizer trim "in the background." If true that appears to be a significant flaw in the design of the system.