Ethiopian airliner down in Africa

[yanrair]

Reference the news article that I referred to, I did not finish reading it and realise now it contains some comments about "foreign" pilots. That is so far from my own position that I can only apologise for providing the link to the article. Having spent most of my life flying with and training pilots from all over the world I could not agree with that contention. This issue has nothing to do with foreign pilots - foreign to whom? USA in this case I think he means. I am a foreigner to someone from China I guess.
The quality of pilots has nothing to do with their ethnicity. I wish to make that very clear. The quality of pilots from anywhere is down mainly to the way they are trained and regulated.
Yanrair

[bsieker]

Originally Posted by yanrair

Bernd. By "every time" we are talking about a rare event but one that did happen. "Every time" a pilot suffers and engine failure on takeoff at V1 - a rare event, he is expected to handle it 100%. That is all we are saying really. Once again it is important to re-state that we don't know what happened on these two flights in any great detail and we await the full reports. What I have tried to do here in the last few days is explain how a 737 is capable of being flown in most all circumstances (not necessarily this exact one) and how it differs from pretty much any other modern plane in that computers are not at its heart. When the report is complete my guess is that there will be multiple factors at play which all contributed to a chain of events - as is so often the case. I will confess that I did not read the full article and will do so now to see where there is a suggestion that "some pilots are idiots" - I didn't pick that up first time around. My apologies.
Cheers
Y

Someone used an interesting word the other day to describe how erroneous MCAS activation is different from an engine failure at v1. The latter is immediately obvious, it is trained for ad nauseam, and it is briefed before every takeoff. Terefore this is an item where we can and must expect near 100% performance. But the former is "insidious". It is not nearly as clear-cut, since other system will repeatedly trim the airplane as well, and a racket of other warnings and noises is also going on. It isn't one (sometimes literal) bang like an engine failure, and you are also not primed for it, because it is not briefed every time. And it is also not acceptable because there are ways to do it better! Rejected takeoff is dictated by raw, high-kinetic-energy physics, and not a lot can be done to get around that.

But most importantly, we know now that not all pilots will handle it well, and to say that only third-world pilots will ever get it wrong is "holier-than-thou"-hubris and no better than "Rep. Sam Graves (R-Mo.)" in the AOPA article.
(EDIT: just read your reply, and don't want to imply that you said or meant anything like that.)

As to "pilots are idiots", I was paraphrasing. What he said a couple of times, though, was "why didn't they simply do x?", which can only be said with hindsight (knowing the actual outcome, and only now knowing the correct solution), and is also arrogant, condescending and serves no purpose other than to feel smugly superiour.

Bernd

[bsieker]

Originally Posted by BrandonSoMD

True enough - but if a third-world flight crew has trouble with other basic skills, would showing them raw AOA really benefit them?

I suppose a good compromise is don't show AOA unless there's a miscompare - then (along with a very obvious miscompare notification) show the left AND right values right next to each other, not cross-cockpit.

I could hardly agree more, although it is also not limited to third-world pilots. I still contend that the AF447 pilots would not have benefited from an AoA indicator, either. I detailed that in another post which got deleted. It boils down to "none of the available instruments made any sense, why would they have believed an additional one, which would have shown an unbelievable value (40°) anyway."

Bernd

[CoffeTime]

You are correct is stating that there is no "piece of equipment for MCAS" on the B-737 -8/9 MEL Rev. 1 dated 01/17/2018 (MMEL Ref. fsims.faa.gov) for MCAS, either under ATA 22 or 27. However, MMELs do cover many "distributed" FUNCTIONS. (As you describe alternatively as "migrated".) Even though there is not a single "box" or "piece of equipment", there can be MEL relief if specified, given that applicable (M) & (O) items are complied with. MCAS would likely qualify as distributed FUNCTION.

[MurphyWasRight]

This should be made clear during ground school, in that the aeroplane manufacturer knows their aeroplane. This means if the QRH calls for a resets without caveats, the pilot should do as per the QRH and NOT try to outthink the system. I know this goes against the grain for those used to the "old" way of doing things but design has moved on.

This brings up an interesting point: If it is -not- in the QRH what then?

Reports suggest that the Lion air crews (both flights) might have been trying to find a match for their situation in the QRH and other manuals. The third pilot on first flight ultimately suggested the trim motor cutouts, not clear if this was before or after he got the large book from his carry on.

One theory is that some crews are trained/held to tight observance of SOP and any actions outside of those are strongly discouraged. This is good as long as the SOP can cover every eventuality, which of course they cannot.

Is it possible the Lion air accident crew did not follow the trim runaway procedure since it was not an exact match for what they were seeing and/or were afraid of consequences if they did and it was later deemed to be not following SOP?

Could this fear have influenced how the prior crew wrote up the incident?

Point being that system knowledge can be vital for undocumented cases, in addition to knowing the procedures understanding what they do and possible side effects is important since it allows problem solving in situations -not- in QRH or other sources.

In the Lion air MCAS case knowing for sure that the cutout switches would work -and- confidence that they could manage the aircraft after they were used might have saved the day.

Really too early to extend to Ethiopian case since not known (to public at least) how similar the cause(s) were.

[Murexway]

Originally Posted by bsieker

But most importantly, we know now that not all pilots will handle it well, and to say that only third-world pilots will ever get it wrong is "holier-than-thou"-hubris....

Well, we can't expect ANY pilots to handle it well, if their differences training was limited to a one-hour session on an iPad that didn't even mention MCAS.

[Rated De]

A little Occam's razor:

Automation is simply nowhere near good enough to replace well trained, remunerated, rested and motivated pilots.

That the incessant cost cutting preferred by both airline management and manufacturers alike is flawed.

[voyageur9]

Originally Posted by Rated De

A little Occam's razor:

Automation is simply nowhere near good enough to replace well trained, remunerated, rested and motivated pilots.

That the incessant cost cutting preferred by both airline management and manufacturers alike is flawed.

Ockham might opine: Automation is good enough to replace average, insufficiently-trained, underpaid, overworked and thus no-longer-motivated pilots. The latter seem increasingly to outnumber the former.

Which is why pilots will soon (probably sooner than they expect) go the way of elevator operators. That may be sad in vaguely nostalgic fashion but will decrease seat costs, ticket prices and fatalities per million flights.

[Sailvi767]

Originally Posted by BobM2

Rananim, a faulty AOA that would activate MCAS would produce a continuous stick shaker at rotation, not on flap retract. Why would any right-thinking pilot ever attempt to retract flaps & continue the flight with an active stick shaker, even if unaware that MCAS exists?

That one is esay, you cross check the 3 airspeed indicators, thrust, performance and attitude to determine if the stickshaker is real or false.

[BobM2]

Originally Posted by Turbine70

What we can only conclude as a design flaw requires recurring RTO above Vr?

Wrong focus.

No, not wrong focus. Nobody is advocating RTO above Vr unless unlimited runway is available. A faulty AOA could give a stick shaker on take-off rotation in any airplane whether it has MCAS or not. The point I am trying to make is if the airplane is climbing & accelerating normally & stick shaker is on one side only, it is an AOA failure & not a valid stall warning. The correct response to this is to return & land the airplane. Get it fixed! You don't accelerate, clean up the flaps & try to continue the flight with an active stick shaker as Lion Air did on two occasions, only one of which was successful (barely).

[fdr]

Originally Posted by infrequentflyer789

Yup. From that same data source (and wishing vbulletin did tables):
737 NG: >20 years, >7000 built*, 20 hull losses, 591 dead
737 MAX: <3 years, ~350 built, 2 hull losses, 346 dead
So, if it's the crews or the airlines and not a problem with the plane, how do you explain the (order of magnitude at least) difference in crash rate?

On the surface that is an interesting observation, however it is the result of working with unequal population sizes and looking at temporal processes. Safety of a system is judged by exceptional events, losses in aviation. overall, historically loss rate has loosely followed a curve similar to long term average costs in economics, a broad U shape. initially there is a potential elevated risk from unknowns in a new system (airline, aircraft, route, operation etc..) which is mitigated by the control loop of the system. After an extended period of time new factors will come into play, which may elevate risk, loss of corporate knowledge, structural fatigue, ageing effects, apathy etc. these are also affected by the overall system response which should improve over time, and it does to an extent, SSID, SMS etc, but the underlying issues are non linear, and the system response is also non linear. Responses hardly ever are exactly correct and without new risks and unintended consequences.

Pretty much, systems are non linear. Estimates based on largely different samples are only correct in say QA sampling, and even then it comes with interesting maths due to uncertainties.

The NG didn't make headlines on safety with its introduction, however there were considerable fatalities from the start for various issues, and the fatality rate then reduced. The losses occurred in the noise of other events, and did not raise eyebrows. in more recent time, we continue to see over runs, loss of control, and similar crew related matters increase on the NG. The A320 started with a lousy run of losses, most due to knowledge issues with the crew related to the automation functions. the A320 loss rate continued to be managed, but there are still wild card events that occur to this day, including loss of control, CFIT and other odd events.

Both of the airlines involved with the most recent events have considerable track records with accidents, all of them raising questions on system integrity. For the regions that they operate in, at least in Africa, ET is one of the better performers. In Indonesia, safety records are always of concern, and JT has had its share of events and losses, which given its size of operation is probably not far from the average in the country. Indonesia like Africa has elevated operational risk factors, that even if comparative operational standards exist would probably lead to more incidents of the type that are most common there, overruns and offs of the runway. Loss of control events have occurred with various aircraft types in the region, for a multitude of reasons, crew turning off the attitude platforms, severe weather encounters...

The question on the Max is why did apparently trained crew not recognise and action a simple procedure in the events. Stab cut out has been fitted since the 40's, when stabs were the solution to high speed flight trim changes. Cutout is not a new device, nor is the problem of uncommanded stabiliser trim changes. So with the Max, what is the reason the crew didn't recognise the need to do a simple action to save the day? The concurrent stall warning would appear to have had a strong influence on the cognitive capabilities of the crew on the day. The revised event information of the JT aircrafts prior flight suggest that on the day that crew also needed additional input to successfully undertake corrective action. The CVR info on JT610 starts to suggest that the crew did attempt to manage the event in a calm manner, but with that process, the hand over of the flying duties from the capt to the copilot had a down side, the captain had been responding to the uncommanded trim, the copilot was not successful in doing the same and the flight path was promptly affected. It is indeed unfortunate that the captain following CRM best practice training principles takes action that appears to have had severe consequences. If the captain had recognised the trim problem consciously, cutout would have been an appropriate action. The copilot was handed an aircraft with the problem, and it is quite possible (unknown at the moment) that the captains successful reactions to the trim problem were subconscious, and that it was being managed so was not communicated at the time of the transfer to the copilot. That point is going to need consideration for any real longterm improvement in problem cueing, where the comprehension of the crew of the actual status is critical. Crew SA is paramount, and what appears to be 3 cases so far had problems in this area.

I don't think that these operators are unique in the issue of SA at all.

[patplan]

Originally Posted by Ian W

---snipped--
Would you really let trim carry on monotonically trim down 2.5 units every 5secs and not switch it off? l can only assume that you would. It is really immaterial why the trim was operating it could be a now dead rodent chewing through an electric cable, you just want the trim to stop and two switches that have been there forever allow you to do that. I am sure that Boeing is aghast that their NNCs for trim runaway were being read in such a contracts lawyer fashion. Perhaps they should review the semantics of all memory items and NNCs/checklists and any training that reinforces those limiting semantics.

The Lion Air crews DID NOT KNOW how many units or even how long this goblin would trim. They didn't even have 10 seconds to observe the trim wheel amidst all the warning. To them, what happened to AC was exactly like what was reported/read in the pre-flight briefing: "STS running the wrong direction due to speed difference". As reported on the Lion Air's A-SHOR:

The conflicting data's [ALL INDICATORS were out of whack - previous flight at least the SIC's indicators were still valid, but not this one], perhaps observing the surrounding, rummaging through the QRH, communicating with the ATC, etc..., were all conspiring to overload their mental faculties and sensory perception. And, to top things off, they didn't have the luxury of having a dead head sitting on the jump seat helping to observe and analyze what's going on.

On the preliminary report, CAPT and/or FO of the previous flight apparently had failed to mention the stick-shaker condition and the NNC for runaway trim they'd performed to overcome what thought to be the STS trim going the wrong way. The last few facts are very much what makes the hole in the Swiss cheese lined up.

[RatherBeFlying]

I'm thinking that the JT610 P1 retrimmed completely from each MCAS excursion, but P2 did not allowing the nose down trim excursions from MCAS to accumulate while P1 was head down in the manual - which had no information on MCAS.

​​​​​​Will the CVR, once released, show whether P1 communicated to P2 what P1 was doing with trim before handing over control?

Remember also that stick shaker was adding workload.

We now know that a faulty AoA will both trigger shaker and MCAS once at a safe height where flaps are normally retracted and more thorough diagnosis of the situation can begin, but then they were handed a new problem.

​​​​​

[RUTUS]

Originally Posted by Ian W

How about the NNCs in all 737s for Runaway Trim? oh of course it is not 'runaway' as it is only repeated (reads from dictionary) nose down trim, so I will let the Stab Trim fly me into the ground rather than switch it off.

Would you really let trim carry on monotonically trim down 2.5 units every 5secs and not switch it off? l can only assume that you would. It is really immaterial why the trim was operating it could be a now dead rodent chewing through an electric cable, you just want the trim to stop and two switches that have been there forever allow you to do that. I am sure that Boeing is aghast that their NNCs for trim runaway were being read in such a contracts lawyer fashion. Perhaps they should review the semantics of all memory items and NNCs/checklists and any training that reinforces those limiting semantics.

Yes recognizing the trim issue is the heart of the matter. That was exactly my point. You cannot make this into "switch off the AP and fly the plane"-scenario. A pilot with poor manual flying skills but being able to identify the issue does much better than a skilled flier who isn't able to identify the issue.

It doesn't help you to switch off AP and AT and stabilize things by flying "power and pitch". You can't because you don't achieve a stable pitch.

So hence my real point, the challenge: Show me that up until six months ago anyone suggested making "stab trim cutout" part of a "disengage auto and fly the plane" if you don't have a clue what the issue is.

The "should they have been able to catch on to the trim issue?" discussion has been done ad nauseam. In my personal opinion the only way to hypothetically get the truth there would be if you could find 20 average pilots who had been in coma for the last six months and put them through a surprise sim scenario replicating an actual MCAS-misfire.
Then we would know how the average pilot would have done.What people with all the facts are now convinced they would have done is not relevant evidence to me.

I bet that if you asked the average px if they were confident that they'd get a life jacket on in case of a water landing landing the vast majority would say yes. They've seen the briefing a gazzillion times. How hard can it be?

Yet we know how many out of a 150 px in the "Sully flight" actually managed to put on a life jacket properly waist strap and all. Was it a three digit number? Was it a two digit number?

[Loose rivets]

Having read every post since the first crash I'm at a loss as to how we're not, for the most part, progressing logical thought.

To see this 'Why didn't they fly the plane'. chanted out again and again is beyond offensive. The congressman has "been in contact with . . ." etc., etc. I'm sure he would have handled the MAX like a Warbird, and saved the day.

For the first time in many, many years on PPRuNe, I'm allowing myself to really bristle at some of the posts.

There are so many factors coming out of the woodwork. The Seattle Times was the first to spell out some of the home truths. The technical article today left me astonished. The rear switch (in the column) removed, and the function of the left and right Stabilizer cut out switches changed in the MAX. ??? Have I missed these points? Are they not correct? They're major factors.

'gums' has a lot of experience and his considered thoughts today about being in the hot seat for those first moments says a lot. Mostly, the problem was NOT bloody obvious, it was, insidious - proceeding in a gradual, subtle way, but with very harmful effects. A word I chose carefully in one of my earlier posts.

[patplan]

Originally Posted by RatherBeFlying

I'm thinking that the JT610 P1 retrimmed completely from each MCAS excursion, but P2 did not allowing the nose down trim excursions from MCAS to accumulate while P1 was head down in the manual - which had no information on MCAS.

​​​​​​Will the CVR, once released, show whether P1 communicated to P2 what P1 was doing with trim before handing over control?

Remember also that stick shaker was adding workload.

We now know that a faulty AoA will both trigger shaker and MCAS once at a safe height where flaps are normally retracted and more thorough diagnosis of the situation can begin, but then they were handed a new problem.

​​​​​

The LEFT/CAPT shaker was triggered immediately, IAS/ALT disagreed as well. Meanwhile, MCAS trim was activated after the AC was flap up.

[gums]

Salute!

Apparently the Chuck Yeager cadre here lives on....
So today we see other examples:

That one is esay [sic], you cross check the 3 airspeed indicators, thrust, performance and attitude to determine if the stickshaker is real or false.
errrr, sir? What's with the airspeed and altitude warning lights ? "No problem, pilgrim, I can tell our speed is O.K. by how fast the trees are going by and the ground ain't getting a lot bigger"

stick shaker is on one side only, it is an AOA failure & not a valid stall warning.
errrr, sir, my stick ain't shakling, therefore, it must not be a valid stall warning, right.? I guess the airspeed and altitude and feel difference lights must also be false, ya think? "trust me, dweeb, I know a stall when I feel one"

Beam me up.

Gums sends...

[TowerDog]

Originally Posted by Loose rivets

Having read every post since the first crash I'm at a loss as to how we're not, for the most part, progressing logical thought.

To see this 'Why didn't they fly the plane'. chanted out again and again is beyond offensive. The congressman has "been in contact with . . ." etc., etc. I'm sure he would have handled the MAX like a Warbird, and saved the day.

For the first time in many, many years on PPRuNe, I'm allowing myself to really bristle at some of the posts.

There are so many factors coming out of the woodwork. The Seattle Times was the first to spell out some of the home truths. The technical article today left me astonished. The rear switch (in the column) removed, and the function of the left and right Stabilizer cut out switches changed in the MAX. ??? Have I missed these points? Are they not correct? They're major factors.

'gums' has a lot of experience and his considered thoughts today about being in the hot seat for those first moments says a lot. Mostly, the problem was NOT bloody obvious, it was, insidious - proceeding in a gradual, subtle way, but with very harmful effects. A word I chose carefully in one of my earlier posts.

Scratching my head now: If the cause of these two accidents was an MCAS event due to a faulty sensor, then the solution would be to click off those two Stab Trim Cutoff switches, then fly the airplane, make a landing, then go to the hotel and have a beer.
I have been practicing the Stab Trim-Run away on Boeing’s in various simulators for over 30 years and I would Hopefully remember these 2 switches if it happened in real life.
If this is beyond what is to expected of airline pilots these days, then I will take the train.

[deltafox44]

Originally Posted by safetypee

[LEFT]Alchad, #2365,
there is merit in your linked reference. https://www.satcom.guru/2019/03/ethi...lion.html#more

It's said that angle of attack disagree was 22°5 (at least on Lion Air). But the AoA vane does not directly measure angle of attack, but angle of airflow around the fuselage, which is higher - about twice the angle of attack - due to aerodynamics around a long body

That means the error at the Angle of Airflow vane was not 22°5 but about 45°, which correspond to the angle between AoA screws.

[Towhee]

"Much like tapping the brake pedal in a car to disengage cruise control, a sharp tug on the controls of older models of Boeing Co’s 737 used to shut off an automatic trim system that keeps the plane flying level, giving the pilot control.

But Boeing disabled the “yoke jerk” function when it brought out the 737 MAX, the latest version of its top-selling jet - and many pilots were unaware of the change, aviation experts told Reuters....

...pilots would have needed to know that MCAS existed, that it had unusual power to force the plane down and that “a hard pull on the yoke” would no longer turn off the automatic trim that uses MCAS, John Hansman, an aeronautics professor at MIT, said in an interview.

“That wasn’t clear to the pilots flying the airplane,” Hansman said. “The training material was not clear on that.”"


https://www.reuters.com/article/us-e...-idUSKCN1R322M