Ethiopian Airlines Crash; Another 737 Max

[Tantalum]

It seems like your opinions are at odds with each other...
- you say not having 3 AoA sensors is idiotic
- you say Boeing will be "vindicated" presumably because you think they're blameless

Do you realize MCAS relies only on one of the AoA sensors?

Boeing is not innocent, but it need not be solely the cause of fatalities.. if you read the comments on any of the NYT or other articles the masses are running around like headless chickens. Likely cause should be the pilots' inability to manually fly a plane (I speak with some jest, but the point stands) with a contributing factor inadequate design and training of the AoA MCAS system

As of now though we still don't actually know WHAT caused the crash, yet we've already indicted the manufacturer and a system which may not have even been active

 

[SkyDog58]

I cannot wait for Boeing to be vindicated in this whole thing.. and they should go after all the media outlets for slander and misinformation (but they won't). This is an international targeting of an American company and an American regulatory body (FAA) that had long been held in high regard to the jealous esteem of other countries, especially those with dodgy safety records (read, basically any third world country). Why wouldn't you want to pile on the public shaming when you see an opportunity to blame a US company, especially one with many defense contracts? John Oliver just had a piece on this. Never forget the human element.


I used to really love Jalopnik.. but recently (last 3-4 years) their articles have been very good at giving just enough information for people to take away misleading insights disguised as fact.. that's the most dangerous thing in my opinion. The article leaves out much of the human factors, trim cut off switches, training, etc., and drives the reader to think that one little sensor is killing hundreds of people (despite the best efforts of heroic pilots wrestling with an automated plane). Jalopnik has also started catering to a certain reader base, so unlike AvWeb, who is genuinely unbiased, most of Jalopnik (Gawker media group) are going to have some clear underlying biases in their publications. Their best authors, like Tyler Rogoway, have since left anyway

View attachment 72704
**this is the paragraph where they left out "pilots may fully disable the auto trim functions of the system and manually fly and trim the airplane if they suspect the system is not performing correctly, such as in this scenario. Boeing's existing 737 training and manuals for a runaway trim situation and subsequent trim cut off feature would still apply and work in this situation, as a false system indication can be inhibited by disabling auto trim and trimming manually. This calls into question the training that the pilots may be receiving and their handling of faulty systems in conjunction with the automated features"


Yes. No one has discussed that yet, not even one sentence in any of the articles that relate to this crash. Because the agenda out there is that Boeing, FAA, and the US are cutting costs for more profit (because corporation = evil, insert stereotypical monopoly man here) and this resulted in lost lives


I mean.. that spinning black and white wheel next to the throttle quadrant is obvious, no? Isn't the FIRST thing most pilots do with unusual control pressures or inputs is go for the trim? I mean we learn that in the first 3 hrs of flight instruction to trim away the control pressure. If the dude was struggling to pull back on the stick, wouldn't he instinctively reach his right hand for the trim wheel and try to move it, or feel it spinning and hit the cut off with his left? That's second nature to most pilot.. isn't it?

If you don’t cease using logic and knowledge to counteract mass hysteria and ignorance, I’ll report you. That sort of behavior just isn’t allowed.

 

[Tommar98]

I don’t doubt in the highly competitive aviation manufacturing world that attacking Boeing is clearly a motive for some. It’s also true that most media reports of aviation issues tend to get dumbed down for general consumption and in the fast paced world of news information saying something -anything - seems to be more important than all the facts. Still, with all that said, the fact that a new system on a new plane may be the common cause in an accident involving two different airlines is worthy is some serious skepticism about what Boeing may or may not have done correctly in either design or instruction. Also, I’ve read on POA numerous times the frustration of pilots for always being the reasons a plane crashed when the final NTSB report comes out. More likely than not in the end it will be a combination of design flaw, system failures, training, documentation, pilot error, airline specific issues, etc.


Sent from my iPhone using Tapatalk

 

[Silvaire]

Again, if it was MCAS then it was not a case of MCAS doing what it was supposed to do and while knowledge and training might be mitigating factors it would still ultimately boil down to a catastrophic failure of that system. My guess is that it's going to take more than a software tweak to fix this.

 

[jallen0]

What the hell? How could this happen that not every single pilot who flies this plane not know this information? And how to fix it.

https://www.bloomberg.com/news/arti...in-cockpit-saved-a-737-max-that-later-crashed

 

[Larry in TN]

If transition training in the MAX concerning the MCAS was not accomplished (or emphasized) the result is rather predictable if a MCAS failure was to occur. Understanding the system is key to surviving a MCAS failure.

No it's not. It's not even helpful.

Here's what would happen with MCAS activating based on invalid data.

MCAS starts trimming the stabilizer in the nose-down direction. As the nose becomes "heavy", the pilot-flying uses the yoke thumb switches to trim up to put the airplane back into trim. The use of the yoke trim switches stops MCAS. Five-seconds pass with nothing happening.

MCAS starts trimming the stabilizer in the nose-down direction. As the nose becomes "heavy", the pilot-flying uses the yoke thumb switches to trim up to put the airplane back into trim. The use of the yoke trim switches stops MCAS. Five-seconds pass with nothing happening.

MCAS starts trimming the stabilizer in the nose-down direction. As the nose becomes "heavy", the pilot-flying uses the yoke thumb switches to trim up to put the airplane back into trim. The use of the yoke trim switches stops MCAS. Five-seconds pass with nothing happening.

After the third, maybe fourth, cycle the pilot should realise that something is wrong and accomplish the runaway stabilizer procedure.

-Grasp control wheel firmly
-Disconnect autopilot (it's already off) and auto-throttles
-Stab trim switches ... Cutout

MCAS is now disabled and manual trim can be used. After the fact, the MCAS-trained pilots might say, "Hey, they may have been an invalid MCAS activation" while the pilots who hadn't been trained on MCAS would only know that they had a runaway stabilizer.

In the Lion Air accident, the fault which apparently caused the invalid MCAS activation was with an AoA sensor/sender. This would have also resulted in stick shaker activation which could have caused some confusion but you still have to fly the airplane first. In a chaotic situation you don't have time to stop and analyse the underlying cause of the failure(s). You have to fly the airplane and apply the most applicable procedures.

 

[nauga]

I don’t doubt in the highly competitive aviation manufacturing world that attacking Boeing is clearly a motive for some.

Clearly, and there is a history behind some of the more visible and public criticism. That being said, you might notice that industry giants who stand to gain the most from a Boeing beat-down have by and large remained silent. This is not unique to this accident.

Nauga,
and the honor system

 

[Briar Rabbit]

New development:
Pilot Who Hitched a Ride Saved Lion Air 737 Day Before Deadly Crash
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 previously undisclosed detail on the earlier Lion Air flight represents a new clue in the mystery of how some 737 Max pilots faced with the malfunction have been able to avert disaster while the others lost control of their planes and crashed. 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.

The so-called dead-head pilot on the earlier flight from Bali to Jakarta told the crew to cut power to the motor driving the nose down, according to the people familiar, part of a checklist that all pilots are required to memorize.

 

[Sluggo63]

There's a lot to unpack here. I'll try my best.

I'll also start out by saying that I don't totally disagree with you, but I think there is more to this than "third world pilots" not being able to hand fly an airplane.

I cannot wait for Boeing to be vindicated in this whole thing.. and they should go after all the media outlets for slander and misinformation (but they won't). This is an international targeting of an American company and an American regulatory body (FAA) that had long been held in high regard to the jealous esteem of other countries, especially those with dodgy safety records (read, basically any third world country). Why wouldn't you want to pile on the public shaming when you see an opportunity to blame a US company, especially one with many defense contracts? John Oliver just had a piece on this. Never forget the human element.

I don't think Boeing will be totally vindicated, and I think the FAA is going to shoulder a substantial part of the blame, as well. There has been a lot of pressure to keep the entire 737 series under one common type rating. Airlines that have a 737 fleet want to keep training costs down, and put pressure on Boeing to make the latest-greatest 737 "common-enough" to get by the FAA as a common type. You can already see this with the higher landing speeds of the -800 series over the older versions. Since Boeing decided to continue to stretch the 737 into 757 proportions rather than actually remake 757s, they had to artificially increase the landing speed of the -800 in order to have sufficient tail clearance on touchdown.

Here's a good article form the LA times describing how the original 737-100 design, centered on being low to the ground to facilitate passenger and baggage loading has been plaguing that aircraft ever since the 737-300 had larger CFM-56 motors placed on it.

https://www.latimes.com/local/california/la-fi-boeing-max-design-20190315-story.html

Don't take it from me. Here's two quotes from another message board by pilots who fly these airplanes day in and day out.

"It will come down to certification basis.
Boeing, at the request of SWA, Alaska Airlines and to a varying degree the big Three, rushed out a response to the A320/321 NEO.
In doing so they discovered that a big under-slung engine on a longer pylon created deleterious effect on maneuver margins near the edge of the envelope. Lacking any type of an intelligent maneuver-assistive FCC they strapped one on to essentially a manual system. And broke all their own rules about critical Flight Control design. Single source, no fail-safe, no comparator, no false-input control. Nothing but a QRH. Having pushed up against the limits of simple common type, they and their airline partners convinced the FAA that these changes were simple and not only did not require training but really only mechanics need know of them. No need to point it out to pilots as it would just confuse them. Nothing should happen and if it does it will be hidden under the general Runaway Stabilizer Trim QRH..."

"Bingo. Forget about MCAS potato and Americans waxing poetic about foreigners not being able to TP-stall recover an airliner like they're reliving their USAF UPT glory days. The quoted above is the real issue, and what needs to be talked about more. Boeing wanted to get away with not incurring certification costs of a new type by frankensteining the 73 certificate. It is therefore poetic justice they would get bent over questions of a sub-system allowed in under the very certification-stretching they've been mining for decades in the first place. About time their cost-cutting and 737 back alley plastic surgery clinic was finally exposed.

They got Capone under the lesser tax evasion, so frankly I couldn't care less whether the foreign case studies were 100% MCAS/sensor related or not. Win's a win. This ought to effectively wash out their gains in choosing to not design the "composite 757", to include accepting the certification costs a clean sheet design would normally incur."
​

This calls into question the training that the pilots may be receiving and their handling of faulty systems in conjunction with the automated features

This is the crux of the matter, no? What is the training that the pilot's are receiving on the Max? From all my 737 friends, I can tell you... minimal. The Max training at one airline who flies 737s consisted of 30 minutes of computer based training that essentially told them how the new displays are configured and that the gear handle doesn't have an "Off" position. Not one mention of the MCAS; not one minute in the simulator discussing differences/practicing procedures. After all, it's a common type rating to the previous 737s, thanks to the FAA, and in part, Boeing. In fact, I'm not even sure if there is a 737 Max 8 simulator out there anywhere.

I mean.. that spinning black and white wheel next to the throttle quadrant is obvious, no? Isn't the FIRST thing most pilots do with unusual control pressures or inputs is go for the trim? I mean we learn that in the first 3 hrs of flight instruction to trim away the control pressure. If the dude was struggling to pull back on the stick, wouldn't he instinctively reach his right hand for the trim wheel and try to move it, or feel it spinning and hit the cut off with his left? That's second nature to most pilot.. isn't it?

The problem with this approach and mindset is perhaps the fact that this mode of failure was never discussed or practiced. This runway stabilizer trim presents itself very differently than any other stab trim runaway that I've seen/practiced. I detailed it in a previous post, so I won't rehash it here, but with every other stab trim runaway, the first action... pulling or pushing against the force stops the trim. This one doesn't. Other stab trim runaways, it doesn't pause for 5 seconds, let you think everything is okay, then start running away again. All modern jets I've flown will give you an annunciation and aural warning if the stabilizer is moving without pilot input. I don't know if the MCAS trim will do that, but based on the nature of why it's trimming, I doubt it would.

Yes, we pilots get paid to do "pilot stuff" when it hits the fan. Fly the airplane, run the checklist, solve the problem. But some problems are harder to solve than others. If you take a problem that may not have been seen before, couple that with other distractions, a experienced (but new) Captain and a brand-new, inexperienced First Officer something that seems easy enough to diagnose here behind our keyboards turns into a soup sandwich very quickly in the jet.

Do I hold Boeing and the FAA to blame for part of this? From what I've read and heard about the certification, yes. Will I blame the crew? Not entirely. I'm guessing it will come out that they probably could have handled things better, but I'm going to hold off judgement on them until the facts are in. Because I know too well how things can go sideways in an airplane and these guys were in all likelihood using every bit of knowledge available to them and doing their damndest to keep the plane flying and solve a puzzle they hadn't seen before.

All I know is that I fly in a big glass house and "thus by the grace of God, go I" because I am not Sky King, I am not infallible and when I leave on my next trip, maybe my FO and I will be the ones faced with a problem we can't solve in time and everyone on all the message boards will be saying "why didn't they... it's so simple... they should'a just..." If that happens, just know I did my best.

 

[Sluggo63]

New development:
Pilot Who Hitched a Ride Saved Lion Air 737 Day Before Deadly Crash
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 previously undisclosed detail on the earlier Lion Air flight represents a new clue in the mystery of how some 737 Max pilots faced with the malfunction have been able to avert disaster while the others lost control of their planes and crashed. 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.

The so-called dead-head pilot on the earlier flight from Bali to Jakarta told the crew to cut power to the motor driving the nose down, according to the people familiar, part of a checklist that all pilots are required to memorize.

This doesn't surprise me one bit. It's amazing the clarity you experience from moving three feet aft of the yokes. When you have the yoke in one hand and thrust levers in the other, you are looking through a soda straw many times. Once you can step back and assess the situation without having to worry about flying the actual plane, it's amazing what you can see.

 

[Sluggo63]

Here's a good article from the Seattle Times. Seems well written with citations from FAA engineers who were on the 737 Max 8 certification team.

https://www.seattletimes.com/busine...yPDzZURZkwCzKKkgL2r7O7JS7uf5NXZIoE0WYi6x0w7fI

In my opinion, if only half of what they printed is factual, Boeing and the FAA are going to have a lot of explaining to do.

Highlights:

• The FAA MCAS hazard analysis document (which was delegated to Boeing to produce) listed the MCAS stabilizer movement limit as 0.6 degrees (out of 5 degrees total travel). After the Lion Air crash, Boeing told the FAA that the actual limit in the airplane was 2.5 degrees, more than 4x what the hazard analysis listed.
• The consequence of an MCAS failure was listed as "hazardous" (higher than "major," less than "catastrophic"). These "hazardous" type of failure modes are required to be based on multiple sensors, the MCAS as a "hazardous" failure is based on just one AOA input.

 

[Spring Ford]

As simply as I can and surely with some errors :-

Never a Jet or multi-engine pilot.

LIONAIR Crash.
Data from preliminary report which includes some FDR parameters from accident flight and the previous flight.

www.flightradar24.com/blog/wp-content/uploads/2018/10/2018-035-PK-LQP-Preliminary-Report.pdf
"PRELIMINARY KNKT.18.10.35.04"
Other copies on Internet. PDF is better quality than my screenshot here.



Captains leg.

On rotate the Captain's stick shaker started - my understanding is that this is loud and unmissable and intrusive. Ran for entire flight except for a short gap.

At that time or very soon afterwards Airspeed disagree and Altitude disagree flags come up. Airspeed and altitude disagree were small - a few percent.

Start troubleshooting.

Small automatic trim pulses from various systems (NOT MCAS). About a dozen in 1m 30s.

1m 20s after take off.
2,000 feet flaps up. MCAS starts down trimming for 10s every 15s.

Master Caution asserted for a about 30 seconds.

Captain does a yoke thumb switch trim pulse for each down pulse but not sufficient and aircraft descends 500ft.

Stick shaker stops for 15-20sec.

2m 20s after take-off.
Flaps get put back down. MCAS stops trimming. Other systems still doing short trim pulses. Trim wheels still move about.

Climbs to 5,000 ft above airport by the looks of it.

4m after take-off
Flaps retracted. MCAS starts down trimming for 10s every 15s

Captain manages to accurately balance MCAS trim with yoke thumb switch trim on AVERAGE. Altitude varies constantly. Range about 1,000ft total but mostly smaller.

Call for return to airport at some stage. Quite a lot of radio work throughout.

Hand off from Tower. Many vectors from ATC. They flew much of a figure 8 path.

FO working with checklists.

Master Caution asserted for a few seconds.

11m after take off.
Captain passes control to FO. Maybe he wanted to focus on troubleshooting, maybe he was physically unable to deal with control column forces for longer? CVR may tell us in final report.

FO fails to yoke thumb switch trim sufficiently to counter 10s in 15s down. They crash very soon after. Perhaps 1 min. There are yoke thumb switch UP trim (ANU) pulses but they are not long enough to compensate.

On previous flight stick shaker ran for WHOLE 2 HOUR flight from rotate to weight on wheels. Completed scheduled route. Stick shaker not mentioned in Maintenance log.

On crash flight :-

There was AoA disagree of about 22 degrees as soon as AoA came alive on take off run. However, there is NO direct indication of this on flight deck. The MCAS system was using the bad one. +22 degrees ANU feed into FCC.

There is AoA compensation fed into the Airspeed and Altitude system (to compensate for static pressure variations with AoA?). This caused the airspeed disagree and alt disagree.

The crew had no knowledge of the existance of the MCAS system. It had been decided it was not a "need to know" system and the crew were not told of its existence.

Still sound easy?

A mentioned by someone earlier much about this incident at pprune.org. Many, very, very good posts amongst the usual variable quality posts.

https://www.pprune.org/rumours-news/619272-ethiopian-airliner-down-africa.html
https://www.pprune.org/tech-log/615709-737max-stab-trim-architecture.html - signal to noise ratio very good here.

Other Threads too in these sub-forums :-
https://www.pprune.org/rumours-news-13/
https://www.pprune.org/tech-log-15/

 

[donjohnston]

I wish I could give this more likes.

As do I!

 

[Sluggo63]

Everyone blamed Audi for "unintended acceleration" events, and cost Audi billions of dollars. The only thing anyone could come up with was that Audi's pedal spacing was different from other vehicles. IOW, pilot error (including one mother, in my hometown, who crushed her son against the back of the garage.)
We (as a society) don't want to blame people, as long as there is an inanimate object, built by a faceless corporation, upon which we can fix blame (Audi, Tesla, Boeing, Bushmaster, Ruger, etc.)

That's not the only thing anyone could come up with. Audi had several recalls, including a shift-brake interlock, but the unintended accelerations continued. They also had a recall for the idle-valve for no apparent reason.

Granted, I'm sure several of the unintended accelerations were due to pedal misplacement, but Toyotas and Jeeps were having several issues and in many of those there was an error in the cruise control module and when shifting from Park to Reverse, the cruise control would accelerate the car, even though it was not engaged. As an aside, every Audi that had a reported unintended acceleration had cruise control installed as an option.

But, the bigger picture is this is all why there is an entire field of study called "Human Factors Engineering." If 99% of the people who drive cars have the accelerator and brake pedal 7 cm apart, and you build a car where the two pedals are only 3 cm apart, that's bad HF. (I just made those numbers up).

Same with the 737 Max 8. It's bad engineering.

 

[Larry in TN]

At that time or very soon afterwards Airspeed disagree and Altitude disagree flags come up (at least on Captains side). Airspeed and altitude disagree were small - a few percent.

It is both sides. "IAS DISAGREE" and "ALT DISAGREE" at the bottom of each airspeed and altitude tape.

Small automatic trim pulses from various systems (NOT MCAS). About a dozen in 1m 30s.

That's the speed trim system (STS). Operates frequently of every departure.

Captain does a manual trim pulse for each down pulse but not sufficient and aircraft descends 500ft

It's electric trim via the yoke thumb switches. Manual trim would be physically turning the trim wheels. Electric trim is the primary system. Manual trim is the backup system.

FO fails to manually trim sufficiently to counter 10s in 15s down. They crash very soon after. Perhaps 1min. There are Manual UP trim (ANU) pulses but they are not long enough to compensate.

Nothing prevents the pilot from using electric trim to return the aircraft to a trimmed state after each MCAS activation. Don't know why he would stop trimming while the nose was still 'heavy'.

 

[sourdough44]

I realize the article mention ‘similarities’ between the two accidents but I haven’t seen where the Ethiopian accident had an AOA input failure? So often the LionAir details get mixed into the 2nd crash, maybe it is very similar?

They seem a bit slow with the data release lately too.

 

[Kenny Phillips]

That's not the only thing anyone could come up with. Audi had several recalls, including a shift-brake interlock, but the unintended accelerations continued. They also had a recall for the idle-valve for no apparent reason.

Granted, I'm sure several of the unintended accelerations were due to pedal misplacement, but Toyotas and Jeeps were having several issues and in many of those there was an error in the cruise control module and when shifting from Park to Reverse, the cruise control would accelerate the car, even though it was not engaged. As an aside, every Audi that had a reported unintended acceleration had cruise control installed as an option.

But, the bigger picture is this is all why there is an entire field of study called "Human Factors Engineering." If 99% of the people who drive cars have the accelerator and brake pedal 7 cm apart, and you build a car where the two pedals are only 3 cm apart, that's bad HF. (I just made those numbers up).

Same with the 737 Max 8. It's bad engineering.

ALL of the unintended accelerations could be countered with the brake pedal, easily. Audi ran one of their cars with the throttle wired WFO to over 100 MPH, and stopped it using the brakes, engine still huffing. When a car goes when it shouldn't, you have other options besides the brake (such as putting the transmission into neutral). Of course, as in an airplane, this requires awareness. That commodity is in short supply these days (and days of yore.) Sort of related, when I was a lot boy for a dealership (my first job) I was backing up a Fiat 131 (the "old" Fiats, not the current iteration) when I hit the brake, but was suddenly going madly toward a wall. Yep, wrong pedal. The pedal spacing was appropriate for children. It was very difficult to lift my foot off of the "brake", but as soon as I did, I was OK, and hit the other brake pedal just in time.

 

[Bill]

These "hazardous" type of failure modes are required to be based on multiple sensors, the MCAS as a "hazardous" failure is based on just one AOA input.

There was AoA disagree of about 22 degrees as soon as AoA came alive on take off run. However, there is NO direct indication of this on flight deck. The MCAS system was using the bad one. +22 degrees ANU feed into FCC.

There is AoA compensation fed into the Airspeed and Altitude system (to compensate for static pressure variations with AoA?). This caused the airspeed disagree and alt disagree.

This is the big one for me. If erroneous AoA data caused MCAS to drive these planes into the ground, Boeing should have a big price to pay. To me it's lunacy to have only one AoA drive a system like MCAS. At the minimum it should have two AoA inputs, and if they disagree by more than $FOO degrees, then the system goes offline with an annunciation to the crew. Better yet is three AoA inputs, one disagrees, warn the crew yet keep the system online. All disagree? Offline.

 

[Bill]

ALL of the unintended accelerations could be countered with the brake pedal, easily. Audi ran one of their cars with the throttle wired WFO to over 100 MPH, and stopped it using the brakes, engine still huffing. When a car goes when it shouldn't, you have other options besides the brake (such as putting the transmission into neutral).

Most people have no clue how a car actually works. If you learn how the systems work together, THEN you have a chance of diagnosing the problem when schidt goes sideways. If not, well, you're just along for the ride.

 

[Piperonca]

Another good article from Fallows this morning: https://www.theatlantic.com/notes/2019/03/jump-seat-pilot-and-boeing-737-max/585301/

 

[Matthew]

My wife’s Toyota was involved in the recall for unintended acceleration. Best anyone could figure was that aftermarket floor mats were catching the gas pedal. There were theories that lead free solder caused problems. Drivers seemed to panic instead of standing on the brakes.

The fix was to shave off about 1/2” from the bottom of the pedal and install a s/w mod. The s/w would cut engine power and increase brake response if the brakes are applied while the vehicle is accelerating. I verified the s/w operation by tapping the brakes while pressing on the gas, it’s a pretty dramatic response.

I think too much control s/w is being developed by people without the experience at the other side. When you develop a control system, you have to make assumptions on the ability of the person using it. Assuming a trained, experienced user will respond a certain way is ok, until that user reacts unexpectedly. Then what? That’s where you need to be able to understand real-life, and that’s where experience on the other side is so important.

 

[LoneAspen]

But, the bigger picture is this is all why there is an entire field of study called "Human Factors Engineering." If 99% of the people who drive cars have the accelerator and brake pedal 7 cm apart, and you build a car where the two pedals are only 3 cm apart, that's bad HF. (I just made those numbers up).

I completely agree with this. I'm all for placing blame on individuals when they screw up, in fact I think personal responsibility is at an all-time low (and getting lower) as more and more people seek to place blame on others for their screw ups. But when you have a manufacturer with billions of dollars of resources to throw into R&D and human engineering, it's simply inexcusable to deploy a design that departs from the norm in such a way that you fail to foresee the failure modes and the consequences. Which in the case of things like vehicles and airplanes, includes injuries and fatalities.

I work with other software and hardware developers all the time who fail to consider edge cases and failure modes. It's almost like they can't conceive the end user would ever do something abnormal, or that their "perfect" system could misbehave and what the consequences might be. My software isn't perfect, but I at least try to plan for edge cases and meaningful error messages back to the user. Key difference is that when our software has bugs or crashes, people don't die. The worst that could happen is an escalation or ****ed off customers and support people. Companies with billions of dollars at their disposal designing systems that could kill people when they fail, have extraordinary extra levels of responsibility to plan for those edge cases and failure modes. And when they fail to do so, and people die, then I think they should fall, and fall hard.

I'm not ready to throw the book at Boeing just yet. There's a lot more data that needs to be collected, and analyzed, before root causes are determined. But if it's proven that a system on that plane contributed significantly to the accidents and deaths, then the guilty party should pay a very heavy price for that. And by heavy, I'm not talking a few million dollars, I'm talking BILLIONs in fines, and restitution to the victim's families.

 

[Kenny Phillips]

My wife’s Toyota was involved in the recall for unintended acceleration. Best anyone could figure was that aftermarket floor mats were catching the gas pedal. There were theories that lead free solder caused problems. Drivers seemed to panic instead of standing on the brakes.

The fix was to shave off about 1/2” from the bottom of the pedal and install a s/w mod. The s/w would cut engine power and increase brake response if the brakes are applied while the vehicle is accelerating. I verified the s/w operation by tapping the brakes while pressing on the gas, it’s a pretty dramatic response.

I think too much control s/w is being developed by people without the experience at the other side. When you develop a control system, you have to make assumptions on the ability of the person using it. Assuming a trained, experienced user will respond a certain way is ok, until that user reacts unexpectedly. Then what? That’s where you need to be able to understand real-life, and that’s where experience on the other side is so important.

Never underestimate the degree of incompetence which your product may encounter!

 

[Spring Ford]

It's electric trim via the yoke thumb switches.

Thanks - that's what I was meaning but it's not clear. I'll try to fix it.

 

[Spring Ford]

I realize the article mention ‘similarities’ between the two accidents but I haven’t seen where the Ethiopian accident had an AOA input failure? So often the LionAir details get mixed into the 2nd crash, maybe it is very similar?

They seem a bit slow with the data release lately too.

The FDR is not public. From ADS-B data the flight profiles are similar. Loss of altitude control soon after take off. Crash after a few minutes.

The LionAir preliminary report showed some very concerning behaviour.

Flightradar24 had the ADS-B for the beginning of the flight right away.

A new and still not fully on-line satellite system apparently handed to the authorities full ads-b for the whole flight and that, with the stab trim jackscrew is what persuaded the FAA to ground the aircraft. Many other authorities went with the Flightradar24 data and pulled the plug.

 

[Bill]

install a s/w mod. The s/w would cut engine power and increase brake response if the brakes are applied while the vehicle is accelerating. I verified the s/w operation by tapping the brakes while pressing on the gas, it’s a pretty dramatic response.

Most new cars now have the "cut power even if the throttle is depressed when the brake is touched" software. And I hate Hate HATE it!

Back in the day, on cars with automatic transmissions, my Dad taught me a nice little trick to use when you're on a side road trying to pull out onto a busy main road with small gaps. As you see the gap, hold the brake with your left foot, and add in enough throttle to bring the revs up to the stall speed of the transmission, and maybe a touch more. When the gap arrives, simultaneously let off the brake and hit the gas and the car goes RIGHT NOW! Works wonderfully! Or at least it used to :-( New cars don't allow you this, try it and it cuts the engine power back miserably.

Also works wonders when backing up in tight quarters. Instead of doing the right foot hop between gas and brake thing, keep the right foot on the gas and modulate the movement with the left foot on the brake.

Every new level of idiot proofing seems to take more control away from those who know that they're doing.

 

[Tantalum]

Check it:
https://qz.com/1576597/off-duty-pilot-saved-lion-airs-737-max-the-day-before-its-fatal-flight/
https://www.theatlantic.com/notes/2019/03/jump-seat-pilot-and-boeing-737-max/585301/
https://www.bloomberg.com/news/arti...in-cockpit-saved-a-737-max-that-later-crashed


I'm sorry, but like Colin Quinn, I'm sticking to my story. Look at the articles linked above and quoted below, especially the Bloomberg one

This fault happened the day before on the Lion Air flight and a jump seating dead head pilot told the crew to cut the electric trim.. which (thank you Bloomberg) is correctly noted in the article as something all pilots are trained to do and required to memorize as a procedure for runaway trim.. and, that Kayoh confirmed up thread in an earlier post (despite Everskyward's implication that my suggestion of cutting the trim is somehow juvenile thinking on my part in that trainers fly different than commercial jets (no ****))

It's particular infuriating that when things go south, rather than *flying the plane* these guys start flipping through operational handbooks and manuals, etc. It's like Air France all over again (which also prompted a lot of critique on Airbus' FBW methodology). Why is it so hard for pilot to revert back to basic airmanship? And how come a deadhead jump seater knew what to do.. and seamingly every single pilot in the US, but not a couple crews from Ethiopia and Indonesia? It's training!!

I also don't understand why MCAS needs documentation if the way it fails is by the trim running away, in which case the trim runaway procedure (which is trained and memorized) is utilized in the same capacity. This makes me think that if the trim runs away (regardless of cause) many crews may not know hot to resolve. Does it matter WHY the trim is running away? I think what's more important is "hey, if the plane starts trimming itself out of whack, then disable the electric trim" <- instead these guys start flipping through manuals rather than fly the plane and use their judgment

From Bloomberg:

But, the bigger picture is this is all why there is an entire field of study called "Human Factors Engineering." If 99% of the people who drive cars have the accelerator and brake pedal 7 cm apart, and you build a car where the two pedals are only 3 cm apart, that's bad HF. (I just made those numbers up).

Same with the 737 Max 8. It's bad engineering.

I appreciate your posts in that they're well written and informative. But I disagree with this.. the more you cater to idiotic behavior (the least common denominator) the more you dumb down and make society more stupid and less capable of thinking for themselves. There was a time when most people knew a thing or two about cars.. could replace a flat, etc. Now this is some kind of dark art wizardry. There was a also a time when people would fly DC3s around the country with little more in the way of navigation than a compass and the stars. Placing pedals 3 cm apart may be a poor design, but basic logic would tell you that if you've suddenly started accelerating the minute you put your foot on the pedal, then maybe instead of pressing it harder, take your foot off? Why do people double down on stupid actions "gee, let me press this pedal harder!"

ALL of the unintended accelerations could be countered with the brake pedal, easily

Yup. But like you astutely pointed out earlier it's much easier to blame a faceless evil greedy corporation than it is to blame the heroic individual. Incidentally, https://www.npr.org/2019/03/14/7034...inst-gun-manufacturer-allowed-to-move-forward a court has indicated that Remington can be sued. This sets a scary precedent.. can we now also sue Wusthof, Stanley, Stihl, etc., any time one of their knives, hammers, axes, chainsaws are used in a murder?

People are raging idiots.

 

[Tantalum]

Every new level of idiot proofing seems to take more control away from those who know that they're doing.

The bar gets lowered every time.. and it's usually a handful of particularly low IQ individuals lowering it for everyone else. The fact that "disable the trim" is not the first thing someone thinks of when the plane starts fighting you is horrifying. "Hi, let me flip through a text book when we're crashing.." It's akin to a driver needing separate checklists for how to slow a car down whether it's a red light or stop sign.. or someone running out in the street in front of you

 

[MauleSkinner]

It's particular infuriating that when things go south, rather than *flying the plane* these guys start flipping through operational handbooks and manuals, etc. It's like Air France all over again (which also prompted a lot of critique on Airbus' FBW methodology). Why is it so hard for pilot to revert back to basic airmanship? And how come a deadhead jump seater knew what to do.. and seamingly every single pilot in the US, but not a couple crews from Ethiopia and Indonesia? It's training!!

Basic airmanship apparently isn't the norm. I don't agree with that, but it appears to be the case.

It's definitely reasonable that the jump seater would identify the problem, because he's a casual observer (slightly less casual than us, I'll admit) and his view isn't as likely to be narrowed by the stress of the moment.

I also don't understand why MCAS needs documentation if the way it fails is by the trim running away, in which case the trim runaway procedure (which is trained and memorized) is utilized in the same capacity. This makes me think that if the trim runs away (regardless of cause) many crews may not know hot to resolve. Does it matter WHY the trim is running away? I think what's more important is "hey, if the plane starts trimming itself out of whack, then disable the electric trim" <- instead these guys start flipping through manuals rather than fly the plane and use their judgment

It doesn't appear, at least based on the A.D., that this is treated as an immediate action or memory item by Boeing. Different manufacturers treat things differently.

Having said that, one of the things that I think is important for pilots to understand is that part of systems knowledge is checklist knowledge...if you don't know a checklist exists, it can't help you. I see pilots all the time who have no clue that a particular checklist exists, even if they've been flying the airplane for years. To me, it's airmanship. But as I stated above, airmanship apparently isn't the norm.

 

[jallen0]

And how come a deadhead jump seater knew what to do.. and seamingly every single pilot in the US, but not a couple crews from Ethiopia and Indonesia? It's training!!

It's also the fact that the deadhead pilot did not have to manage the entire emergency. He could sit there and just think for a moment and not have to be reacting like the other pilots had to. There is a lot to be said for the ability to just step back, watch what's happening, and then allow a different solution to come to you.

 

[Brad Smith]

We are now fighting the computer for control of our modern airliners. Doesn't anyone remember "Hal"?

 

[Tantalum]

It's definitely reasonable that the jump seater would identify the problem, because he's a casual observer (slightly less casual than us, I'll admit) and his view isn't as likely to be narrowed by the stress of the moment.

It's also the fact that the deadhead pilot did not have to manage the entire emergency. He could sit there and just think for a moment and not have to be reacting like the other pilots had to. There is a lot to be said for the ability to just step back, watch what's happening, and then allow a different solution to come to you.

Great points, and something I missed in my (admittedly) rant. But that also comes down to a CRM thing

 

[Checkout_my_Six]

yup...it should be treated as a run away trim. Disengage hal....re-trim and hand fly. Easy peasy....

 

[Tantalum]

We are now fighting the computer for control of our modern airliners. Doesn't anyone remember "Hal"?

Disable the MCAS trim!
I'm sorry Dave, I can't do that

 

[Tantalum]

As an aside.. then I'll go away for a bit I promise, but as important as checklists are they can't replace good judgment. It's like some people require a checklist to go to the bathroom "okay, now I need to wipe.. wait, do I wipe and then flush, or do I flush and then wipe. When do I wash my hands and lock the door?!" We are capable of rational, logical, autonomous thought.. we should use it

You'll see this when some people practice engine outs.. it's like they assume the world pauses while they methodically read a checklist "mixture rich, magnetos on both, carb heat on, switch tanks" - in the meantime the plane is losing airspeed, turning, and flying to god knows where as the pilot's head is buried reading off obvious items

 

[Sluggo63]

yup...it should be treated as a run away trim. Disengage hal....re-trim and hand fly.

I agree.

Easy peasy....

I disagree.

 

[Checkout_my_Six]

for those interested....an AD for the MCAS system was issued Nov 7, 2018.

Runaway Stabilizer
Disengage autopilot and control airplane pitch attitude with control column and main electric trim as required. If relaxing the column causes the trim to move, set stabilizer trim switches to CUTOUT. If runaway continues, hold the stabilizer trim wheel against rotation and trim the airplane manually.
Note: The 737-8/-9 uses a Flight Control Computer command of pitch trim to improve longitudinal handling characteristics. In the event of erroneous Angle of Attack (AOA) input, the pitch trim system can trim the stabilizer nose down in increments lasting up to 10 seconds.
In the event an uncommanded nose down stabilizer trim is experienced on the 737-8/-9, in conjunction with one or more of the indications or effects listed below, do the existing AFM Runaway Stabilizer procedure above, ensuring that the STAB TRIM CUTOUT switches are set to CUTOUT and stay in the CUTOUT position for the remainder of the flight.
An erroneous AOA input can cause some or all of the following indications and effects:
• Continuous or intermittent stick shaker on the affected side only.
• Minimum speed bar (red and black) on the affected side only.
• Increasing nose down control forces.
• IAS DISAGREE alert.
• ALT DISAGREE alert.
• AOA DISAGREE alert (if the option is installed).
• FEEL DIFF PRESS light.
• Autopilot may disengage.
• Inability to engage autopilot.
Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before moving the STAB TRIM CUTOUT switches to CUTOUT. Manual stabilizer trim can be used before and after the STAB TRIM CUTOUT switches are moved to CUTOUT.

 

[midwestpa24]

It's amazing the clarity you experience from moving three feet aft of the yokes. When you have the yoke in one hand and thrust levers in the other, you are looking through a soda straw many times. Once you can step back and assess the situation without having to worry about flying the actual plane, it's amazing what you can see.

I've noticed that just in the change from the left seat to the right seat as a flight instructor. You can see the big picture so much clearer when its someone else fumbling their way through a steep turn or stall.

 

[Matthew]

How does an Airworthiness Directive, from FAA, get to foreign airlines? I don't know how the Ethiopian Civil Aviation Authority and Ministry of Transport work with Boeing and FAA to get that information to their own airlines.

 

[Sluggo63]

As an aside.. then I'll go away for a bit I promise, but as important as checklists are they can't replace good judgment. It's like some people require a checklist to go to the bathroom "okay, now I need to wipe.. wait, do I wipe and then flush, or do I flush and then wipe. When do I wash my hands and lock the door?!" We are capable of rational, logical, autonomous thought.. we should use it

You'll see this when some people practice engine outs.. it's like they assume the world pauses while they methodically read a checklist "mixture rich, magnetos on both, carb heat on, switch tanks" - in the meantime the plane is losing airspeed, turning, and flying to god knows where as the pilot's head is buried reading off obvious items

Honestly, don't go away. Civil discussion is good.

I'll let you in on a little secret. We use checklists for everything at the airlines. We don't shut engines down without the checklist. We don't (generally) flip switches in an abnormal situation without the checklist directing us to. There's a very good reason for that. Safety.

In Air Force pilot training, all new students would learn the mantra of Emergency Procedures. "Maintain aircraft control, analyze the situation, and take appropriate action." It's when you jump from Step 1 to Step 3 when bad things happen. As a AF UPT Instructor, I would teach my students what I was taught to do in an emergency. First step (after "Fly the Airplane"): wind the clock. We had analog clocks in all our airplanes. Just reach up there and wind it. The big picture behind that was "don't do anything." When you do something quickly, there's a good chance it may be wrong. More things go wrong when you rush than when you stop and think about what you're doing.

"Slow is smooth and smooth is fast."

"Just don't do something, stand there"

That's what the airlines learned. When pilots rushed, they missed things. Important things. So we use a checklist. Always.

Most airlines will have some memory items that they deem are important enough to have you commit them to memory (Rapid Depressurization: Oxygen Masks--ON). But even for an Engine Fire all we have in the 757 is:
1. Autothrottle Arm Switch--OFF
2. Thrust Lever--Idle
And we don't even do that until we're at least 1000' AGL. We don't actually shut the engine down until much later, and it's only by the checklist.

There's very few things in a large airplane that is going to kill you right away. Runaway stab trim is going to be one of those things, but of the four large, transport category aircraft I've been qualifies in, it was only a memory item in the 777. It isn't in the 757, nor was it in the MD-11 or the KC-135.

My caveat to all that is to never forget to "Maintain Aircraft Control." If I thought that flipping off the Stab Trim Switches was going to save my life, you better be sure I would take that chance and do it without the checklist. But I'd say more problems have been created by not following the checklist than just going all "John Wayne" and flipping switches and levers without guidance.

If you want to see a good example of someone balling up an (almost perfectly) good airplane because they decided not not use checklists, here's a YouTube video:

And these weren't some fourth, third or even second world aviators. These were our guys.