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Indonesian aircraft missing off Jakarta

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Indonesian aircraft missing off Jakarta

Old 16th Nov 2018, 14:41
  #1321 (permalink)  
 
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Hm.. I guess that might be the difference between the fatal and previous flights. Pilots alone can't (practically not literally) execute stab trim cutout when the nose down trim is significant, they have to level up plane fist; and then, 5 sec window of opportunity is given until auto trim activates again. Contrary to that, with free pair of hands in cockpit your scenario is quite imaginable.
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Old 16th Nov 2018, 15:07
  #1322 (permalink)  
 
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Originally Posted by PashaF View Post
Hm.. I guess that might be the difference between the fatal and previous flights. Pilots alone can't (practically not literally) execute stab trim cutout when the nose down trim is significant, they have to level up plane fist; and then, 5 sec window of opportunity is given until auto trim activates again. Contrary to that, with free pair of hands in cockpit your scenario is quite imaginable.
Four reasonably similar accidents, what is common?

AF447. Schiphol, Asiana SFO, possibly Lion Air.

All started with (qualified) flightcrew losing SA, and not being prepared (without judgment) for an increasingly critical flight path. A stable flight condition started to go sour, and imo, crew could not keep up. Unacceptable.

Something is missing from the flight path formula. (Or included, depending on POV?).

All developed when the breakdown from boring (familiar) airframe performance became rapidly terrifying. Name one accident where crew started with a prepared mental folder ready to cope.

I don’t think it is lack of training. We have become complacent with aircrew not understanding the airframe?

Training involves repeating what is known. It is lack of basic knowledge of the aircraft that created these tragedies, and in Lionair, the knowledge was withheld.

Without (moral) judgment...

Last edited by Concours77; 16th Nov 2018 at 15:17.
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Old 16th Nov 2018, 15:23
  #1323 (permalink)  
 
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Originally Posted by PashaF View Post
... As for technician-crew interactions, i don't think there were any. Technical guy mission (most logically) was not consulting but observation.
Nobody knows what role the technician played on the flight, unless any specific "maintenance-type" actions might be traceable on the DFDR. For all we know, perhaps he was not even in the cockpit. Despite the previous 3 sectors all having control issues due faults, the operator claimed that he was there in a neutral role.
My hunch is (1) assuming he was on the flightdeck, and (2) assuming the crew exhausted all ideas as you said would happen after 5 minutes of running the checklist, then (3) accessing real-time maintenance data from the flight deck displays was only about 2 or 3 clicks away. Boeing proudly touts this capability, new to the MAX: "Many operators have asked that the 737 MAX include access to additional airplane data, and that data be securely made available to flight, cabin, and maintenance teams during flight or while on the ground." And from later in the article: "The onboard maintenance function will be capable of reducing no-fault found events by correlating system status indications to detailed system and equipment faults..."
There's even a maintenance screen for Present Leg Faults.
Source: 737 MAX Advanced Onboard Network System (Boeing, AeroMagazine, pp 5-11)
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Old 16th Nov 2018, 16:06
  #1324 (permalink)  
 
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Originally Posted by Concours77 View Post


Four reasonably similar accidents, what is common?

AF447. Schiphol, Asiana SFO, possibly Lion Air.

All started with (qualified) flightcrew losing SA, and not being prepared (without judgment) for an increasingly critical flight path. A stable flight condition started to go sour, and imo, crew could not keep up. Unacceptable.

Something is missing from the flight path formula. (Or included, depending on POV?).

All developed when the breakdown from boring (familiar) airframe performance became rapidly terrifying. Name one accident where crew started with a prepared mental folder ready to cope.

I don’t think it is lack of training. We have become complacent with aircrew not understanding the airframe?

Training involves repeating what is known. It is lack of basic knowledge of the aircraft that created these tragedies, and in Lionair, the knowledge was withheld.

Without (moral) judgment...
The trend you outlined is indeed terrifying, however, i don't thing that this accident fits in "AF447. Schiphol, Asiana SFO, possibly Lion Air" pattern.
In this instance, pilots were well aware about upcoming technical problems, and obviously discussed their counteraction prior to takeoff.

Germany Flight 888T is the closest analogy i think.
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Old 16th Nov 2018, 16:51
  #1325 (permalink)  
 
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Concours, re 4 similar accidents. #1334,
Recalling that we might always ‘find what we look for’, an alternative POV.
Start with the technical malfunctions and associated weak or complex alerting indications. AF447, 737 Schiphol RA, CRJ Sweden Att, Lion, …

Pilots don’t ‘loose’ SA; this view requires understanding (definition) of what ‘this SA’ consists of, and what aspects the crew had before they lost ‘it’, and why they lost it.
In order to improve our hindsight biased understanding, the better view is that the crews’ SA was insufficient to manage the situation, but without knowing their actual perceptions and understanding at that time, or their mental resource to update these, we cannot conclude anything about the crews performance except that it may have been the best for the situation as they ‘saw’ it. The situation overwhelmed the human, so fix the situation not the human.

If those situations were at or beyond human capability, it is unlikely that any further understanding (training) will improve this, particularly without knowledge of ‘lost SA’. Instead we should look at the overall system in which we ask humans to operate in, and the manner in which we ‘outsiders’ look in - generally backward.

The better approach is to start with the machine and operating environment and consider what might be changed. AF447; the pitot change was in progress, but in other accidents the technical malfunctions are as yet not even in work; perhaps delayed or unrecognised by the blindness of the ease of blaming humans.
An intriguing association in many of these accidents is ‘grandfather rights’, situations ‘not identified in certification’, and the covert belief that ‘the pilots will always manage’.
From this we might conclude that the people in the design and certification processes also encountered situations which were beyond their human capabilities, understanding, or forethought. If so then we might be reaching the limits of safety.




Last edited by alf5071h; 16th Nov 2018 at 17:08.
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Old 16th Nov 2018, 17:02
  #1326 (permalink)  
 
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All the talk about the new 737 MCAS (Manoeuvring Characteristics Augmentation System) is reminiscent of the MD-11 LSAS (Longitudinal Stability Augmentation System) from 30 years ago. Even the name is eerily familiar. I wonder if it was onetime McDonnell Douglas designers, now in senior positions at Boeing, who came up with it. To paraphrase, LSAS was an electronic system which varied the pitch according to its own rules to ensure stability. Compared to its predecessor DC-10 the aircraft had a smaller tail, to reduce drag, and thus smaller elevators, and LSAS was provided to compensate in handling. LSAS was implicated in a number of both hard landings and actual accidents, where the aircraft just did not handle how the crew expected. Not for nothing was it known at the time as the "Scud", because 'you never knew where it was going to land'. Several major purchasers, particularly in the US, were spooked by its characteristics, and sold the aircraft off prematurely. How many of the 200 MD-11 built were lost in sudden instability landing accidents ?

As I understand it, today's team in Seattle (well, in Chicago actually, now the top management have moved themselves away from the worthwhile company members) were concerned about things like common type ratings with the previous models, so it had to be presented as sufficiently similar to those. Which of course it was. MCAS not on the old models, so no need to mention it.
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Old 16th Nov 2018, 17:05
  #1327 (permalink)  
 
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At best we might speculate that the crew ‘should’ have been prepared for some abnormality. Depending on reporting, briefing, etc, the crew could have formed an inappropriate mindset of expectation.

When encountering the inflight malfunction - we don’t know what they actually saw, only our speculation on what we know of the MCAS discussion so far, and not discounting alternative situations, - the crew could easily have considered the wrong problem, or even the right problem with difficulty.
Our view of the outcome of either circumstance might be the same - we don’t know.
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Old 16th Nov 2018, 17:22
  #1328 (permalink)  
 
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MCAS

It’s not stopped by the Pilot pulling the Yoke
This design differs from STS according to AMM NG and its problematic.The FCC wont command STS against pilot inputs on the stick but in the case of MCAS it does.So if the crew have recognized the UAS but not the insidious trim due startle factor their pull up inputs are ignored for 9 seconds.They can still trim up electrically but ....

No design is perfect but this looks like a can of worms for Boeing.The MCAS design( the way it overrides a pilots input to a primary flight control surface ie elevator is frankly scary and a departure for Boeing) is too different from STS for type commonality.And no simulators available to demonstrate its design, operation and inherent dangers.My God. If I was flying the MAX,I wouldnt take off/land with the AP STAB trim engaged.MCAS apparently operates at 0.27u/sec which equates to AP trim speed with flaps down.I am still assuming they mandated RUNAWAY STABILIZER NNC as the solution in the AD so as not to rewrite any checklists(UAS).
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Old 16th Nov 2018, 17:44
  #1329 (permalink)  
 
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What effects might MCAS have during a manual, low speed, clean aircraft Windshear recovery?
Recalling that the system is designed to alleviate some of the effects of thrust induced pitch up, but its still trimming forward in normal operation at the lower airspeeds (higher AoA).
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Old 16th Nov 2018, 20:06
  #1330 (permalink)  
 
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Originally Posted by STBYRUD View Post


I'll do you one better, that procedure is unchanged since the classic 737!
Proof from Rev 31 of the 737 300-500 QRH straight from Boeing, dated June 14, 2013...

This is not only the age of 'fake news', but more importantly the age of people publishing things, be it in the media, or 'just' on a forum somewhere on the internet, without knowing what they are talking about or doing a minimum amount of research beforehand. Thats why I wrote a few posts ago that all this talk about the 'shocking revelation' that Boeing is 'withholding information' about MCAS is absolutely silly - especially since we still don't know what happened to this particular plane.
And, here's an interesting study from the FAA site on Line Pilot Performance of Memory Items for 737CL and NG pilots with 16 line pilot volunteers. One of the test cases was runaway stab. Salient results below (which would seem to validate QRH to some extent):
Four pilots made commission errors in the completion of the runaway stabilizer trim checklist by attempting to activate the electric trim switches in the direction opposite the runaway. One of those four pilots stated that he would also attempt to engage a different autopilot in the hopes that it would not experience the same malfunction (Figure 3).
Control column.....................Hold firmly
Autopilot (if engaged)...........Disengage
> Electric trim in opposite direction
> Engage other autopilot
If runaway stabilizer continues:Trim cutout switches...............Cutout
Trim wheel.....................Grasp & hold
Figure 3. Runaway Stabilizer Commission Errors.

https://www.faa.gov/about/initiative...mory_items.pdf

Last edited by b1lanc; 16th Nov 2018 at 20:50. Reason: format
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Old 16th Nov 2018, 20:13
  #1331 (permalink)  
 
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Originally Posted by b1lanc View Post
And, here's an interesting study from the FAA site on Line Pilot Performance of Memory Items for 737CL and NG pilots with 16 line pilot volunteers.
And, the current Boeing FAA-approved checklists for runaway stab have no memory items, right?
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Old 16th Nov 2018, 21:26
  #1332 (permalink)  
 
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Tidbits from FSB Report

When a new minor model is added to a type certificate, one of the things that happen is that the FAA evaluates the new model to determine what differences training is required for pilots transitioning between models. The results of this evaluation are published in the Flight Standardization Board Report. Reading through the current 737 FSB report, there is no mention of the MCAS system. This is not too surprising in hindsight, as if MCAS has beeen included in the FSB report, appropriate transition training would have been developed.

The tidbit of information is that there was apparantly a change to the “Stab Trim cutout switches panel nomenclature” between NG and Max, and it was evaluated as requiring additional training betond just reading the AFM and FCOM.

Do any of our resident MAX/NG pilots have any information they can share regarding either the transition training or the change to the wording of the stab trim cutout switch placard?

http://fsims.faa.gov/wdocs/fsb/b737_rev_15.pdf#page13
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Old 16th Nov 2018, 21:46
  #1333 (permalink)  
 
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Originally Posted by STBYRUD View Post


I'll do you one better, that procedure is unchanged since the classic 737!
Proof from Rev 31 of the 737 300-500 QRH straight from Boeing, dated June 14, 2013...

This is not only the age of 'fake news', but more importantly the age of people publishing things, be it in the media, or 'just' on a forum somewhere on the internet, without knowing what they are talking about or doing a minimum amount of research beforehand. Thats why I wrote a few posts ago that all this talk about the 'shocking revelation' that Boeing is 'withholding information' about MCAS is absolutely silly - especially since we still don't know what happened to this particular plane.
Note that the "condition - continuously' in the procedure does not describe the MCAS behavior in the (postulated) faulty AOA sensor condition since it works in 10 second (max) bursts with 5 second pauses.
Totally true that following this will remove MCAS trim inputs, if the condition was recognized.

As others have pointed out until the Boeing/FAA missives the existence of this feature was not known to operators or line pilots.
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Old 16th Nov 2018, 22:02
  #1334 (permalink)  
 
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As a result of musing about slacktide's question re transition training from NG to MAX, I simply googled a few relevant phrases to get started on a search. Such terms as "transition training from NG to MAX" and "Boeing differences training for 737 MAX" will get one into the thick of a lot of documents very quickly, Although there are dozens, if not hundreds, of interesting items (varying of course from Boeing technical documents and press releases to various CAA and operator documents) the strongest impression one gets is this: The highest levels at Boeing -- and/or their legal eagles -- must be wishing they could take back a whole whack of stuff they've been writing and saying for the past four years or so on the subject of Max v/s NG differences and training.

post facto est XX / XX
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Old 16th Nov 2018, 23:33
  #1335 (permalink)  
 
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Originally Posted by MurphyWasRight View Post
Note that the "condition - continuously' in the procedure does not describe the MCAS behavior in the (postulated) faulty AOA sensor condition since it works in 10 second (max) bursts with 5 second pauses.
Totally true that following this will remove MCAS trim inputs, if the condition was recognized.

As others have pointed out until the Boeing/FAA missives the existence of this feature was not known to operators or line pilots.
“Interrupted” (continual, NOT continuous) TRIM is NOT “Runaway” TRIM. The recovery procedure is not “totally true”. Boeing gratuitously “referred Pilots to “existing” procedures” as if they would recognize the condition. They could NOT have recognized the problem, It bore NO resemblance to true “runaway trim”. A burst of Trim, followed by absence of Uncommanded Trim sounds like the “occasional StallStall” 447 crew experienced. There is no way to see this problem as “partially known” as Boeing’s inference would have the public believe.

I can only repeat my earlier conclusion: How can Boeing be trusted to disclose any other differences NG/Max? They have no credibility. The regulatory process has morphed into “trust me, I build big airplanes”.
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Old 16th Nov 2018, 23:36
  #1336 (permalink)  
 
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Salute!

HEY!!!! Slack asked a question, and thus far in our thread I cannot find a definitive post from a current "Max" pilot.

Hello? Would love to hear from somebody that has touched the elephant, or ridden it.

Gums asks....
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Old 17th Nov 2018, 00:35
  #1337 (permalink)  
 
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I was able to find some photos of the MAX and NG stab trim cutout switches on Jon Ostrowers old flightblogger photoreel:

737 MAX:

737 NG:

It appears that the two trim systems which were labeled "Main Elect" and "Autopilot" on the NG are now labeled "Pri" and "B/U" on the Max. One would ASSume that this means Primary and Backup. It would be useful to know if there are any operational changes to the system besides the labels. It is unlikely that they would have made have made a change to the labels without a reason.

Last edited by slacktide; 17th Nov 2018 at 00:36. Reason: Fixed links
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Old 17th Nov 2018, 01:03
  #1338 (permalink)  
 
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Originally Posted by infrequentflyer789 View Post
For EASA-FAA, bilateral agreements mean that each basically rubber-stamps the other's approvals. They are, however, completely independent organisations and each has its own rubber stamp.
No, not a rubber stamp. The FAA FAR and EASA CS regulations are for the most part the same, but there are some significant differences. When a new TC or ATC is applied for, there is a meeting between EASA and the airframer and they agree to a list of 'significant regulatory differences' between the relevant FARs and CSs - this is documented in a CRI (Certification Review Item - it's basically what EASA calls an FAA Issue Paper). For the CS regulations listed in that CRI, compliance must be shown separate to the FAA compliance (btw, the FAA doesn't call them FARs, they are CFR (Code of Federal Regulations) - and the FAA can be quite anal about it if you call them the FARs).
In my case, the primary regulation I needed to worry about being different was 25.901(c) - the FAR basically says 'no single failure shall result in an unsafe condition' - while the CS basically says you need to comply with CS 25.1301 (which means a probabilistic analysis). It's a subtle but significant difference - interestingly it can be easier to show compliance for the CS than the FAR. Items on the list of differences often drive their own, dedicated CRIs, or sometimes CAI (Certification Action Items). Similar to FAA Issue Papers, all CRIs and CAIs must be addressed and closed prior to type cert.
Now, EASA makes a separate agreement where they decide if they'll delegate approval of a particular item to the FAA, or retain it themselves. Again, in my case, EASA retained 25.901(c). On the 747 there was a CRI for 25.901(c) we had a number of meetings with EASA and even did some simulator sessions with EASA pilots before we were able to close the CRI.
In effect, EASA does do their own certification, but only for particular items that they decided were of particular interest.
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Old 17th Nov 2018, 01:19
  #1339 (permalink)  
 
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Am I right in understanding that the previous 737s 'stability augmentation systems', otherwise known as the STS, only ever used a speed signal, and that the innovation with the Max was the use of AOA in at least part of it? If so, I have a certain sympathy for the Boeing controls people since they seem to have tried to correct a basic mistake in the original system, to whit, using speed as a proxy for AOA. I count myself lucky in never having to fly the 737, only 75 and 767. The 757 had STS, copied I suspect from the earlier models, the 767 didn't. The result was that the 767 could be happily flown all the way down final approach with minimal input, while the 757 needed constant attention except in a complete flat calm. I don't think that excuses the lack of information in the AOM, though you can see why they may have thought the change in sensor would be transparent.
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Old 17th Nov 2018, 01:37
  #1340 (permalink)  
 
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Originally Posted by Airbubba View Post
And, the current Boeing FAA-approved checklists for runaway stab have no memory items, right?
Well if the Max is simply the next-next-next-final gen 737 then you would think those items would be inherited - with one exception. I do believe Boeing introduced some automation that is not typical of a legacy 737 Boeing product - i.e. MCAS.

The FAA example showed 25% of the group of volunteers not remembering memory items correctly for aircraft they flew. We don't know exactly what transpired in the prior 3 segments to 610 (for that matter we don't really know what happened on the flight deck of 610), but at least one crew 'seemed' to recover from a nose down trim experience on the way to Jakarta at a lower altitude (can I assume that 'I don't have to manually re-trim the bloody thing as often' might be a reason?). I really hope they find the CVR.

There are nearly 40 airlines/lease companys/corps that are flying the Max. I've seen the union statements in the US representing the three affected carriers, but what's happening on the International scene (other than Lion)? Very quiet. I get that the airlines don't want to suggest that some of their new fleet is unsafe (Electra/Comet anyone?). But there must be some dialog going on.
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