Let's please keep the thread on topic and avoid conspiracy theories. Let's stick to what we know and what's been reported by reputable sources.

✈️ atcsundevil

I would have been more impressed if they had bought in the NTSB, the Air Force has been struggling with its hypoxia issue so their investigative talents may be over stretched.

OldAeroGuy wrote:

You are not correct that the Stall Warning recovery procedure says use full thrust. Instead, it says "Advance thrust levers as needed".

You can see the procedure in the link below.

https://imgur.com/JyM0nKQ

You are correct, it seems I was using an older version. Like this one:
http://www.737ng.co.uk/737-800%20Quick% ... QRH%29.pdf

You find it many times on the internet.

OldAeroGuy wrote:

rheinwaldner wrote:

So I ask you: if you have ias disagree and stick shaker, which procedure would you follow? And why would you ignore the other? What if a third condition would arise (overspeed)? Stick shaker and overspeed procedures conflict to the largest possible extend. Once their speed reached 250, it did not matter, why they were not able to climb or cut thrust (maybe the stick shaker made them keeping thrust at 100%), at that point they had to raise the flaps in order to maintain structural integrity.

This is where "Airmanship" comes into play. The pilots have to decide what guidance to follow. A safe course would have been to fly out to the Flap 5 placard of 250 KIAS to lessen the chance a stall, then pitch up to control airspeed and climb to a safe altitude at 250 KIAS, say 5000' AGL. At that point, perform the 80% N1, 10 deg pitch "Airspeed Unreliable" drill to sort out the Airspeed issue. After assessing the condition of the airplane, planning could have been done to Return to Land. Zeke, a well know and respected ATR pilot on this forum, has endorsed this course of action.

I could figure out a safe course also after discussing it first for 30 days. Truth is, that the case is absolutely not so clear and also not easy if you have only some seconds to make these decisions.

For example if you think, that unreliable airspeed memory items are Ok to apply at a later point, after flying for minutes doing something else (which depends on having airspeed b.t.w.), then you dont understanding the urgency of the ias disagree checklist.

If you are honest, stick shaker was easy to determine as false alarm (which it was, stall was at no point imminent). Because with their thrust setting, their pitch and their vertical it was obvious even without speed, that the aircraft was accelerating and stall was not a danger anymore -> hence the stick shaker must be wrong -> the approach to stall procedure is not relevant anymore.

Please note also, that the stick shaker was only on one side. A clear sign, that the stick shaker itself might unreliable.

In this flight both pilots had stick shaker and raised their flaps anyway too:
http://www.tsb.gc.ca/eng/rapports-repor ... o0031.html

B.t.w. this Canadian case would very likely have been brought down by MCAS too if it would have been a MAX...

OldAeroGuy wrote:

Flaps up was selected around 235 KIAS. ET302 was not at 246 KIAS Flaps down as you are implying.

Left or right PFD? Anyway, not soon after they had 246. Soon after that it was 260, then 280. Do you think that raising the flaps then was appropriate? Regardless of the reason why the speed was like it was.

rheinwaldner wrote:

For example if you think, that unreliable airspeed memory items are Ok to apply at a later point, after flying for minutes doing something else (which depends on having airspeed b.t.w.), then you dont understanding the urgency of the ias disagree checklist.

Yes, they could have gone to the "Airspeed Unreliable" drill immediately at Flaps 5 if they were willing to do it at about 1000' AGL. Cutting thrust back to 80% N1 and setting pitch at 10 deg would have kept them from overrunning the Flaps 5 placard

It was an option and part of good "Airmanship".

rheinwaldner wrote:

If you are honest, stick shaker was easy to determine as false alarm (which it was, stall was at no point imminent). Because with their thrust setting, their pitch and their vertical it was obvious even without speed, that the aircraft was accelerating and stall was not a danger anymore -> hence the stick shaker must be wrong -> the approach to stall procedure is not relevant anymore.

Please note also, that the stick shaker was only on one side. A clear sign, that the stick shaker itself might unreliable.

For this case, it was fine. However, the stick shaker could also have been present if there had been leading edge slat damage/skew. In that case, retracting Flaps was absolutely the wrong thing to do. The crew made no effort to assess the airplane situation before retracting the Flaps.

The Stall Warning procedure does not ask for analysis of left/right or both stick shakers. It says if stick shaker is on, DO NOT retract Flaps.

rheinwaldner wrote:

In this flight both pilots had stick shaker and raised their flaps anyway too:
http://www.tsb.gc.ca/eng/rapports-repor ... o0031.html

Let's examine the facts of this case.

- About 54 sec into the flight, both pilots' stick shakers were reported to have activated for 6 - 8 sec. This was not recorded by the FDR.

- At 1:25, the right stick shaker came on for 3 sec. The FDR did record this event.

- At approximately 2:00, Flaps up was selected. At this time, no stick shaker was active.

This a major difference between Sunwings 531 and ET302.

- When ET302 retracted Flaps, there was a CONTINUOUS stick shaker.

- When Sunwings 531 retracted Flaps, there was NO stick shaker.

If a stick shaker is not active, there is no prohibition against retracting Flaps.

rheinwaldner wrote:

B.t.w. this Canadian case would very likely have been brought down by MCAS too if it would have been a MAX...

If the airplane in this case had been a MAX, MCAS would have been inactive after Flaps up as there was no stick shaker, indicating there was no erroneous AoA signal.

This being the case, MCAS would not have been issuing any airplane nose down commands. There is no reason to think MCAS would have brought down Sunwings 531 if it had been a 737 MAX.

OldAeroGuy wrote:

rheinwaldner wrote:

Please note also, that the stick shaker was only on one side. A clear sign, that the stick shaker itself might unreliable.

For this case, it was fine. However, the stick shaker could also have been present if there had been leading edge slat damage/skew. In that case, retracting Flaps was absolutely the wrong thing to do. The crew made no effort to assess the airplane situation before retracting the Flaps.

So was the crew action "fine" or was the crew making "no effort" ? If the "no effort" apply, please describes the "effort" you are taking about in details.

Olddog wrote:

I think that EASA is fed up with Boeing media campaign and issued a counter balance declaration:

Europe Says 737 Max Won’t Fly Until Its Design Review Complete

The European Aviation Safety Agency is running a parallel investigation into the design of Boeing Co.’s 737 Max and says it won’t clear the grounded jet to fly again until that is finished.

“The completion of the independent EASA design review is a prerequisite to the return to service of the aircraft for EASA,” a spokesman for the agency said Tuesday by email.

The decision to conduct its own review is not unusual for the European regulator but underscores a splintering in trust between the world’s two most important safety agencies triggered by the U.S. Federal Aviation Administration’s response to the crash of an Ethiopian Airways Max jet in March. EASA issued instructions to carriers to ground the aircraft ahead of the FAA, breaking previous convention.

CAAC, CATC, EASA, JCAB representatives have also been meeting in London. Could it be that the narrow Boeing / FAA definition of the MAX design, is being widened by this group?

The same organisations, but not with identical reps, have also met regarding a review of grandfathering and certification.

PixelFlight wrote:

OldAeroGuy wrote:

rheinwaldner wrote:

Please note also, that the stick shaker was only on one side. A clear sign, that the stick shaker itself might unreliable.

For this case, it was fine. However, the stick shaker could also have been present if there had been leading edge slat damage/skew. In that case, retracting Flaps was absolutely the wrong thing to do. The crew made no effort to assess the airplane situation before retracting the Flaps.

So was the crew action "fine" or was the crew making "no effort" ? If the "no effort" apply, please describes the "effort" you are taking about in details.

Making an effort to access the airplane would start with running the "Airspeed Unreliable" checklist.

1) Determine which airspeed indicator was reliable after comparison with the standby indicator.

2) Make sure PF had reliable airspeed.

3) Communicate with ATC an intention to return to land.

3a) Optional: Ask the Lead FA to look at the wings and report if there are differences in the Left/Right Slats/Flaps. Cell phone pictures would be a help.

4) Make an over-weight landing at Flaps 5.

4a) Optional:Based on 3a), make an over-weight landing at Flap X (Crew choice).

OldAeroGuy wrote:

For example if you think, that unreliable airspeed memory items are Ok to apply at a later point, after flying for minutes doing something else (which depends on having airspeed b.t.w.), then you dont understanding the urgency of the ias disagree checklist.

Yes, they could have gone to the "Airspeed Unreliable" drill immediately at Flaps 5 if they were willing to do it at about 1000' AGL. Cutting thrust back to 80% N1 and setting pitch at 10 deg would have kept them from overrunning the Flaps 5 placard

It was an option and part of good "Airmanship".
[/quote]

All the while battling with increasing nose down trim in a very rapidly devoloping situation, and with training that was specifically and intentionally withheld from them . I think it is unfair to place all these factors in a crew’s hands and then say they were lacking good airmanship. There is only so far that you can reasonably expect to push a human being. Remember that when it came to the NG the airmanship of these crews was by and large sufficient to operate that aircraft without any issue. is there room to learn from the crews actions? Always! And their actions will form a part of the investigations. But thinking that their actions are front and centre at the cause of this tragedy is choosing to ignore the massive elephant in the room.

smaragdz wrote:

OldAeroGuy wrote:

Yes, they could have gone to the "Airspeed Unreliable" drill immediately at Flaps 5 if they were willing to do it at about 1000' AGL. Cutting thrust back to 80% N1 and setting pitch at 10 deg would have kept them from overrunning the Flaps 5 placard

It was an option and part of good "Airmanship".

All the while battling with increasing nose down trim in a very rapidly devoloping situation, and with training that was specifically and intentionally withheld from them . I think it is unfair to place all these factors in a crew’s hands and then say they were lacking good airmanship. There is only so far that you can reasonably expect to push a human being. Remember that when it came to the NG the airmanship of these crews was by and large sufficient to operate that aircraft without any issue. is there room to learn from the crews actions? Always! And their actions will form a part of the investigations. But thinking that their actions are front and centre at the cause of this tragedy is choosing to ignore the massive elephant in the room.

You need to rethink this paragraph.

At Flaps 5 (or any other Flaps down setting), MCAS is not active. There would have been no increasing nose down trim.

Nose down trim only started when Flaps were retracted and MCAS began to trim nose down due to the erroneous AoA signal.

If you read my prior posts, the ET crew "Airmanship" issue is tied to their decision to retract Flaps with an active stick shaker, contrary to Boeing procedure.

smaragdz wrote:

OldAeroGuy wrote:

Yes, they could have gone to the "Airspeed Unreliable" drill immediately at Flaps 5 if they were willing to do it at about 1000' AGL. Cutting thrust back to 80% N1 and setting pitch at 10 deg would have kept them from overrunning the Flaps 5 placard

It was an option and part of good "Airmanship".

All the while battling with increasing nose down trim in a very rapidly devoloping situation, and with training that was specifically and intentionally withheld from them . I think it is unfair to place all these factors in a crew’s hands and then say they were lacking good airmanship. There is only so far that you can reasonably expect to push a human being. Remember that when it came to the NG the airmanship of these crews was by and large sufficient to operate that aircraft without any issue. is there room to learn from the crews actions? Always! And their actions will form a part of the investigations. But thinking that their actions are front and centre at the cause of this tragedy is choosing to ignore the massive elephant in the room.

If the ET crew had gone to the AIRSPEED UNRELIABLE checklist immediately the only thing they would have been battling would have been a stick shaker going off (and a slight forward pressure on the column if the EFS (elevator feel system) was activated?). They wouldn't have been "battling with an increasing nose down trim" because the MCAS doesn't fire until the flaps are UP. Both engines were functioning, I believe it was a CAVU (Ceiling and Visibility Unlimited) day out and they weren't in danger of running into anything. After that if they brought the flaps up then MCAS would be an issue but there was a bulletin out addressing that, something the Lion Air crew didn't have.

The FAA is so concerned about the future of Boeing's 737 Max that it is bringing in NASA and the Air Force to help ensure it is safe to fly again

The panel is made up of experts from the FAA, NASA, the US Air Force, and a branch of the Department of Transportation. None of the members of the panel were involved in the initial certification of the plane

Boeing said it welcomed the new group and that all at the company "look forward to working with the panel."

Source: https://amp.businessinsider.com/boeing- ... fix-2019-5

Looks like Boeing had screwed up real bad this time over and the reliability of Boeing seems to be at a record low.

@EmoticonsAllDay Thanks for the link, so the FAA are calling in additional agencies..it is beginning to look like it is going to take more than a quick software fix to get the 737MAX back in the air.

The Australian 60 Minutes programme is also well worth watching. The pilots feel they have been been kept in the dark about MCAS and wonder if there are anymore hidden secrets in the 737.

flyingphil wrote:

@EmoticonsAllDay Thanks for the link, so the FAA are calling in additional agencies..it is beginning to look like it is going to take more than a quick software fix to get the 737MAX back in the air.

The Australian 60 Minutes programme is also well worth watching. The pilots feel they have been been kept in the dark about MCAS and wonder if there are anymore hidden secrets in the 737.

If you work for a 3rd world country airline like Lion ..... i would wonder the same thing. If I am a pilot for an western airline like AA, UA, SW, and others, those pilots should be fine.

EmoticonsAllDay wrote:

The FAA is so concerned about the future of Boeing's 737 Max that it is bringing in NASA and the Air Force to help ensure it is safe to fly again
[i]
The panel is made up of experts from the FAA, NASA, the US Air Force, and a branch of the Department of Transportation. None of the members of the panel were involved in the initial certification of the plane

Hopefully that is THE reason, and not simply to 'protect' FAA if they give a sign off, and another accident occurs.

Europe Says 737 Max Won’t Fly Until Its Design Review Complete

The invisible hand of the free market hard at work.

Can I ask what I think is a yes or no question really, would the Max gain momentum and immediate approval from all the agencies, if it simply had the engine placement redesigned and pulled down a bit or atleast made similar to the NG engine design?

I'm well aware such a thing would be stupid costly, but, is it actually, a bad option to consider?

7BOEING7 wrote:

smaragdz wrote:

OldAeroGuy wrote:

Yes, they could have gone to the "Airspeed Unreliable" drill immediately at Flaps 5 if they were willing to do it at about 1000' AGL. Cutting thrust back to 80% N1 and setting pitch at 10 deg would have kept them from overrunning the Flaps 5 placard

It was an option and part of good "Airmanship".

All the while battling with increasing nose down trim in a very rapidly devoloping situation, and with training that was specifically and intentionally withheld from them . I think it is unfair to place all these factors in a crew’s hands and then say they were lacking good airmanship. There is only so far that you can reasonably expect to push a human being. Remember that when it came to the NG the airmanship of these crews was by and large sufficient to operate that aircraft without any issue. is there room to learn from the crews actions? Always! And their actions will form a part of the investigations. But thinking that their actions are front and centre at the cause of this tragedy is choosing to ignore the massive elephant in the room.

If the ET crew had gone to the AIRSPEED UNRELIABLE checklist immediately the only thing they would have been battling would have been a stick shaker going off (and a slight forward pressure on the column if the EFS (elevator feel system) was activated?). They wouldn't have been "battling with an increasing nose down trim" because the MCAS doesn't fire until the flaps are UP. Both engines were functioning, I believe it was a CAVU (Ceiling and Visibility Unlimited) day out and they weren't in danger of running into anything. After that if they brought the flaps up then MCAS would be an issue but there was a bulletin out addressing that, something the Lion Air crew didn't have.

What a collection of nonsense.

An airspeed disagree was not detected by the crew nor the aircraft in the ET accident case.
The airspeed values only diverged slightly if you look at the FDR data, so no reason for the crew to call that checklist.

The first action of the crew was to activate the left AOA sensor heat, so they were quite quickly aware of where the issue originated and decided to ignore the stick shaker and continue normal climb procedures, which includes raising the flaps to avoid flaps overspeed.

The Boeing Bulletin was not very specific.
It said that erroneous AOA data CAN cause nose down trim.
It didn't say that erroneaous LEFT AOA data WILL cause nose down trim.

https://theaircurrent.com/aviation-safe ... air-crash/



Per this bulletin, the pilots need to proceed with normal procedures and act only if necessary by following the runaway stabiliser non-normal checklist.
In addition, the correlation between the flaps position and MCAS activation was not mentionned in the Boeing bulletin.

The ET pilots have done exactly what the bulletin instructs them to do and followed each step in the required order.

What you are suggesting is that the pilots should have jumped the gun, and shouldn't have followed procedures in the order required starting from a conclusion that you know but the pilots couldn't know at the time, including the fact that flaps positions affect MCAS.

If you are a pilot with that attitude, you are going to be a frequent visitor to the chief pilot's office, you will fail check rides, until eventually you will make a hole in the ground.

Buffalomatt1027 wrote:

flyingphil wrote:

@EmoticonsAllDay Thanks for the link, so the FAA are calling in additional agencies..it is beginning to look like it is going to take more than a quick software fix to get the 737MAX back in the air.

The Australian 60 Minutes programme is also well worth watching. The pilots feel they have been been kept in the dark about MCAS and wonder if there are anymore hidden secrets in the 737.

If you work for a 3rd world country airline like Lion ..... i would wonder the same thing. If I am a pilot for an western airline like AA, UA, SW, and others, those pilots should be fine.

Thomson Reuters · Posted: Apr 28, 2019 1:58 PM ET | Last Updated: April 28
American Airlines pilots have warned that Boeing Co.'s draft training proposals for the troubled 737 MAX do not go far enough to address their concerns, according to written comments submitted to the U.S. Federal Aviation Administration and seen by Reuters.

https://www.cbc.ca/news/business/boeing ... -1.5114538

Jamie514 wrote:

Buffalomatt1027 wrote:

flyingphil wrote:

@EmoticonsAllDay Thanks for the link, so the FAA are calling in additional agencies..it is beginning to look like it is going to take more than a quick software fix to get the 737MAX back in the air.

The Australian 60 Minutes programme is also well worth watching. The pilots feel they have been been kept in the dark about MCAS and wonder if there are anymore hidden secrets in the 737.

If you work for a 3rd world country airline like Lion ..... i would wonder the same thing. If I am a pilot for an western airline like AA, UA, SW, and others, those pilots should be fine.

Thomson Reuters · Posted: Apr 28, 2019 1:58 PM ET | Last Updated: April 28
American Airlines pilots have warned that Boeing Co.'s draft training proposals for the troubled 737 MAX do not go far enough to address their concerns, according to written comments submitted to the U.S. Federal Aviation Administration and seen by Reuters.

https://www.cbc.ca/news/business/boeing ... -1.5114538

Those same AA pilots who said that .... also knew how to turn off disable the MCAS system and right the plane.

(1) New News: AOA Disagree Alert logic was not working correctly (turns off when the logic detects AOA option not installed). Boeing engineers (but not senior management!) knew about it a year before the first crash but didn't tell anybody about it.
(2) If Source Selection logic is triggered by the Disagree logic, then .... is this now a possible root cause for incorrect trigger of MCAS in both accidents?


So all that Disagree logic (threshold and hysteresis logic) and all that Source Selection logic (to determine which sensor is good) goes down the drain (ie not used) because someone tied in (at the last minute?) an AOA install option. Which in their minds would have to mean "hey, if you don't think you need this option, well then you better have some really good pilots to deal with what we're gonna give you next".

**Wait, I didn't mean to say that. I didn't. I meant to say, hey, we put alot of resources into that Disagree logic when I was on the team. I know it works. Besides why would they screw that up? Anyway, they need this stuff shipped tomorrow, and I'm not getting any attaboys for finding problems at this stage. So what I mean is.... I'm on the Source Selection project, and that disagree stuff is... well not my problem. It's not. I can't do everything. Right? Right!!?? Right.

Waterbomber2 wrote:

7BOEING7 wrote:

smaragdz wrote:

All the while battling with increasing nose down trim in a very rapidly devoloping situation, and with training that was specifically and intentionally withheld from them . I think it is unfair to place all these factors in a crew’s hands and then say they were lacking good airmanship. There is only so far that you can reasonably expect to push a human being. Remember that when it came to the NG the airmanship of these crews was by and large sufficient to operate that aircraft without any issue. is there room to learn from the crews actions? Always! And their actions will form a part of the investigations. But thinking that their actions are front and centre at the cause of this tragedy is choosing to ignore the massive elephant in the room.

If the ET crew had gone to the AIRSPEED UNRELIABLE checklist immediately the only thing they would have been battling would have been a stick shaker going off (and a slight forward pressure on the column if the EFS (elevator feel system) was activated?). They wouldn't have been "battling with an increasing nose down trim" because the MCAS doesn't fire until the flaps are UP. Both engines were functioning, I believe it was a CAVU (Ceiling and Visibility Unlimited) day out and they weren't in danger of running into anything. After that if they brought the flaps up then MCAS would be an issue but there was a bulletin out addressing that, something the Lion Air crew didn't have.

What a collection of nonsense.

An airspeed disagree was not detected by the crew nor the aircraft in the ET accident case.
The airspeed values only diverged slightly if you look at the FDR data, so no reason for the crew to call that checklist.

The first action of the crew was to activate the left AOA sensor heat, so they were quite quickly aware of where the issue originated and decided to ignore the stick shaker and continue normal climb procedures, which includes raising the flaps to avoid flaps overspeed.

The Boeing Bulletin was not very specific.
It said that erroneous AOA data CAN cause nose down trim.
It didn't say that erroneaous LEFT AOA data WILL cause nose down trim.

https://theaircurrent.com/aviation-safe ... air-crash/



Per this bulletin, the pilots need to proceed with normal procedures and act only if necessary by following the runaway stabiliser non-normal checklist.
In addition, the correlation between the flaps position and MCAS activation was not mentionned in the Boeing bulletin.

The ET pilots have done exactly what the bulletin instructs them to do and followed each step in the required order.

What you are suggesting is that the pilots should have jumped the gun, and shouldn't have followed procedures in the order required starting from a conclusion that you know but the pilots couldn't know at the time, including the fact that flaps positions affect MCAS.

If you are a pilot with that attitude, you are going to be a frequent visitor to the chief pilot's office, you will fail check rides, until eventually you will make a hole in the ground.

The Boeing Bulletin specifically states the pilots must completely counteract the trim inputs by the MCAS system and deactivate the stab trim with the cutout switches. Neither crew accomplished that task, so yes, it is clear what’s required and it wasn’t done.

GF

If anyone thinks pressure to complete testing and deliver the plane is new might read the NTSB report on the G650 crash.

“Gulfstream’s focus on meeting the G650’s planned certification date caused schedule related pressure that was not adequately counterbalanced by robust organizational processes to prevent, identify, and correct the company’s key engineering and oversight errors.”

https://www.ntsb.gov/investigations/accidentreports/pages/AAR1202.aspx

GF

Buffalomatt1027 wrote:

Jamie514 wrote:

Buffalomatt1027 wrote:

If you work for a 3rd world country airline like Lion ..... i would wonder the same thing. If I am a pilot for an western airline like AA, UA, SW, and others, those pilots should be fine.

Thomson Reuters · Posted: Apr 28, 2019 1:58 PM ET | Last Updated: April 28
American Airlines pilots have warned that Boeing Co.'s draft training proposals for the troubled 737 MAX do not go far enough to address their concerns, according to written comments submitted to the U.S. Federal Aviation Administration and seen by Reuters.

https://www.cbc.ca/news/business/boeing ... -1.5114538

Those same AA pilots who said that .... also knew how to turn off disable the MCAS system and right the plane.

And if thats the last of the surprises, we're off to the races. Meanwhile I'll happily believe the American professionals saying they want more info and simulator training which corroborates the 60 Minutes Australia reporting you dismiss as if it was a purely foreign issue.

Waterbomber2 wrote:

The Boeing Bulletin was not very specific.
It said that erroneous AOA data CAN cause nose down trim.
It didn't say that erroneaous LEFT AOA data WILL cause nose down trim.

https://theaircurrent.com/aviation-safe ... air-crash/



Per this bulletin, the pilots need to proceed with normal procedures and act only if necessary by following the runaway stabiliser non-normal checklist.
In addition, the correlation between the flaps position and MCAS activation was not mentionned in the Boeing bulletin.

The ET pilots have done exactly what the bulletin instructs them to do and followed each step in the required order.

You are misunderstanding what the bulletin/EAD called for. It updated the FCOM and QRH to note that erroneous AoA on a MAX can cause uncommanded nose down trim and that, if it does, it should be treated like runaway stabilizer. It directed the crew to run the runaway stabilizer NNC. The NNC specifies that manual (electric) trim should be used to balance control column forces followed by moving the stab trim switches to cutout.

Had the ET crew done this, this thread wouldn't exist. Instead they started doing the correct procedure but moved the switches to cutout before the control column forces were balanced. This is a statement of fact that can be seen in the preliminary report.

The Lion Air crew did not recognize the situation as a runaway stabilizer likely because, prior to the first MAX crash, runaway stabilizer was described as continuous movement and MCAS was intermittent. I'll never understand why they stopped using the trim switches to counter MCAS because it was working. But, I don't blame them for not running the proper NNC because they didn't know anything about MCAS.

The ET crew should have known exactly what they were dealing with so soon after the Lion Air crash and EAD so there is no reason for them not to have run the NNC properly but they didn't.

DenverTed wrote:

Europe Says 737 Max Won’t Fly Until Its Design Review Complete

The invisible hand of the free market hard at work.

Huh? Why is this being posted as some major revelation? Why would any agency that grounded the MAX lift the grounding BEFORE they complete their design review? This "news" is like posting that I'm going to cook a hamburger before I eat it.

DenverTed wrote:

Europe Says 737 Max Won’t Fly Until Its Design Review Complete

The invisible hand of the free market hard at work.

Nonsense. Government intervention is the antithesis of the Invisible Hand theory. Europe's "hand" here is quite visibible, and certainly is not the market at all.

I find it interesting that there's so much focus on the pilots in this thread. On and on... and yes, they quite possibly or perhaps even likely made mistakes*, acted as one of the cheese holes. I But if you are blaming them for not figuring out the right procedure, perhaps you should hold others to the same criteria.

Lets take aircraft design and certification under the same analysis. For safety critical and regulated systems you are supposed to follow a careful process which includes at least the following things:

1. Analyze and understand the potential safety hazards of your system.
2. Build the necessary safeguards to prevent serious accidents.
3. Document the usage and hazard prevention processes
4. Test the system to ensure that it works as designed and processes work with real users
5. Certify the system with the relevant authority.

(Not necessarily in this waterfall order.)

Now, if we look at THIS procedure then it becomes pretty clear that BOEING ... shall we say had a number of failures. For instance:

1. Hazards:
- Recurrent application of the MCAS actions was not understood to be a safety hazard.
- Difficulty in recognising this type of intermittently working "runaway" was not understood.
- You have to wonder if even the possibility of a sensor failure was properly considered.

2. Safeguards:
- The system did not do any kind of cross checks between two sensors
- (Let alone what would have been in my software engineer perspective the proper three-way check design a la A320 and others.)
- There was no ability to prevent repetitive erroneous application.

3. Document:
- The system was not documented for the users (= pilots)
- Even after the first accident, the procedure documentation was unclear (e.g., the that usage of the electric switches needs to happen prior to cutout was IMHO unclear)

4. Test the system to ensure that it works as designed and processes work with real users
- There does not appear to have been this kind of testing, and per reports not even the test pilots have understood the full parameters of the MCAS system
- The real users have not had an opportunity to train the usage of the safety relevant features and their failure modes. They still are not getting it, except for an iPad course. Yet, the procedures are time-critical and appear in a potentially-confusing multi-warning situation.

5. Certify the system with the relevant authority.
- The system was certified, but per reports certification agency was only told about the milder version of the MCAS authority, the actually built system was much more forceful.

Do I need to spell out how this looks? 0/5... I think Boeing does share a good portion of the blame. And please, if you insist on sending 1000 messages on this board criticising the pilots, could you perhaps consider the total picture at least occasionally? To not look like someone with an agenda.

*) One comment about the pilots: I could list the issues of overspeeding and flaps. But, just follow how the opinion on this board has changed over time. Few months after the accidents, it is still evolving. The first reaction in the Lion Air case was that maintenance should have sent a bad plane out, then it became "why not just cut the switches", then later after ET it was "why hadn't they received the training" and then "why cut the switches before using the electric trim long enough" and now flaps and speed. I think in reality the pilots made mistakes, but they also weren't given a very clear map of how to navigate the complex maze of stall, trim, speed, and other issues, all warnings blazing at the same time. Other crews probably could have saved the day, maybe even majority of the crews. But that's not good enough. This needs to be orders of magnitude safer overall system (a system including the pilots and the plane).

The airpseed unreliable checklist for the 737 has been criticized more than once in the past:

For example:
http://www.aaiu.ie/sites/default/files/ ... 13-017.pdf

And here is a QRH handbook for a NG http://www.737ng.co.uk/737-800%20Quick% ... QRH%29.pdf

Look at part 10.1

In addition you want to look at the performance section "Flight With Unreliable Airspeed - Climb", which says "Flaps Up, Set Max Climb Thrust"

seahawk wrote:

The airpseed unreliable checklist for the 737 has been criticized more than once in the past:

For example:
http://www.aaiu.ie/sites/default/files/ ... 13-017.pdf

And here is a QRH handbook for a NG http://www.737ng.co.uk/737-800%20Quick% ... QRH%29.pdf

Look at part 10.1

In addition you want to look at the performance section "Flight With Unreliable Airspeed - Climb", which says "Flaps Up, Set Max Climb Thrust"

From the report:

The Boeing Aircraft Company B737NG QRH checklists should provide
guidance for flight crew specifying the systems that might be affected
and the possible warnings generated as a consequence of a pitot
failure

Does someone on here has the QRH for the MAX in case of a AoA sensor failure?

And if so, is it lacking information for the pilots as well, especially regarding MCAS?

I am not a pilot and it can be confusing to read through a lot of posts here discussing technical aspects of individual theories on the cause of the two MAX accidents. For those of you with technical knowledge regarding this matter- can you please try to post in language that the average person can understand? This thread is about the aircraft being out of service in Q2 and also to discuss developments regarding when they will return to service (at least that’s what I get from the title of this thread topic).

Question- the Lion Air aircraft that crashed was flown the previous day by a crew that encountered a similar situation. How were those crew members able to recover? And in what way was it related to the sequence of events experienced by the crew on the day of the incident?

Also- what relevance will the successful recovery of the crew the day prior have on future training for MAX pilots, and what relevance does that have in comparison to how the crews of both flights that crashed reacted?

Thank you for any insight.

The Lion Air crew the previous day had a third pilot on the jump seat, who seems to have noticed the movements of the trim wheels starting again after a time and so they performed the runaway trim checklist and the problem was solved.

seahawk wrote:

The Lion Air crew the previous day had a third pilot on the jump seat, who seems to have noticed the movements of the trim wheels starting again after a time and so they performed the runaway trim checklist and the problem was solved.

Did the third pilot have knowledge of something that the working crew did not? Thank you for the reply.

airplaneboy wrote:

seahawk wrote:

The Lion Air crew the previous day had a third pilot on the jump seat, who seems to have noticed the movements of the trim wheels starting again after a time and so they performed the runaway trim checklist and the problem was solved.

Did the third pilot have knowledge of something that the working crew did not? Thank you for the reply.

He had a different view and wasn't distracted by the other tasks involved in flying the plane.

airplaneboy wrote:

seahawk wrote:

The Lion Air crew the previous day had a third pilot on the jump seat, who seems to have noticed the movements of the trim wheels starting again after a time and so they performed the runaway trim checklist and the problem was solved.

Did the third pilot have knowledge of something that the working crew did not? Thank you for the reply.

Not that I am aware off. The only benefit he had was the other seating position (which imho helps in that case) and not being busy flying the plane.

So Leeham is reporting today that the FAA could go ahead and lift the grounding ahead of other certification authorities.

I hope that at least during this process that the FAA and EASA can go in lock step or I predict that certification will be much more costly in future. This may require the FAA to hold off some.
If those two agencies lift the grounding together it is then likely that most of the rest of the world (excluding China) will follow suit.

China is driven by politics (as I fear increasingly the FAA is)

FAA was the last agency to ground those faulty planes. It's under heavy pressure of boeings lobbyists to undo the grounding ASAP. I hope the rest of the world stays independent and does full due dilligence.

I agree that the FAA is under pressure from Boeing (and probably via lobbying the politicians) to lift the grounding quickly. My argument is that to do so ahead of the rest of the world (especially EASA) would forever harm the FAA and with it impact future certification processes.

The FAA would then (under political pressure) retaliate on the next Airbus certification and we have another stupid element of a trade war.

StTim wrote:

I agree that the FAA is under pressure from Boeing (and probably via lobbying the politicians) to lift the grounding quickly. My argument is that to do so ahead of the rest of the world (especially EASA) would forever harm the FAA and with it impact future certification processes.

Yes.

Slow is sometimes better, and this is one of those times.

StTim wrote:

I agree that the FAA is under pressure from Boeing (and probably via lobbying the politicians) to lift the grounding quickly. My argument is that to do so ahead of the rest of the world (especially EASA) would forever harm the FAA and with it impact future certification processes.

The FAA would then (under political pressure) retaliate on the next Airbus certification and we have another stupid element of a trade war.

It would probably be a huge own goal if the FAA starts a certification war with EASA over the MAX-re-certification.

As the trade talks between the US and China seem to fall apart, you cannot infuriate your other huge market.

If the CAAC and the EASA determine the MAX needs more inspections before certification more national authorities will follow them than the FAA.

Boeing cannot win a US vs RoW trade war. Airbus is less dependent on the US market than Boeing on the market outside the US.

Additional to this, if the FAA allows the MAX to fly again, alone, and there is another incident, they are done in the eyes of every other agency. This risk is too high even if the chance is 1 in a million, because the consequences will be enormous.

The Air Force and NASA?
That's weird, especially the USAF as they have no experience with civil aircraft certification standards.

Perhaps this may be related to intellectual property rights? NASA and USAF have veto power on pending patents through the invention secrecy act.

StTim wrote:

So Leeham is reporting today that the FAA could go ahead and lift the grounding ahead of other certification authorities.

I hope that at least during this process that the FAA and EASA can go in lock step or I predict that certification will be much more costly in future. This may require the FAA to hold off some.
If those two agencies lift the grounding together it is then likely that most of the rest of the world (excluding China) will follow suit.

China is driven by politics (as I fear increasingly the FAA is)

This is old news. FAA have said this all along. They are maintaining their independence. the American psyche could not accept anything like subservience to ROTW. Doesn't mean they will go against ROTW, but it will be seen as their decision to go along with any recommendations or not.

I expect they will wish to assert pre-eminence (real or imagined) as soon as possible.

Ray

Wre aterbomber2 wrote:

The Air Force and NASA?
That's weird, especially the USAF as they have no experience with civil aircraft certification standards.

Perhaps this may be related to intellectual property rights? NASA and USAF have veto power on pending patents through the invention secrecy act.

Quickly available high class safety critcal design and software analysts I would think more likely. The sort of people you might want to do a 'deep dive'.

Ray

They selected parties that were not involved in the original MAX certification work to find out if something was left out.

sgrow787 wrote:

(1) New News: AOA Disagree Alert logic was not working correctly (turns off when the logic detects AOA option not installed). Boeing engineers (but not senior management!) knew about it a year before the first crash but didn't tell anybody about it.
(2) If Source Selection logic is triggered by the Disagree logic, then .... is this now a possible root cause for incorrect trigger of MCAS in both accidents?

Code: Select all

Disagree? -----yes----> Source Selection -----> Use good AOA sensor (discarding bad)
Disagree? -----no ----> Use onside AOA sensor (hey we don't have a disagree, so AOA-onside must be good if it doesn't disagree with AOA-offside) ----> let's use AOA-onside even if it may be bad** ----> CRASH

So all that Disagree logic (threshold and hysteresis logic) and all that Source Selection logic (to determine which sensor is good) goes down the drain (ie not used) because someone tied in (at the last minute?) an AOA install option. Which in their minds would have to mean "hey, if you don't think you need this option, well then you better have some really good pilots to deal with what we're gonna give you next".

**Wait, I didn't mean to say that. I didn't. I meant to say, hey, we put alot of resources into that Disagree logic when I was on the team. I know it works. Besides why would they screw that up? Anyway, they need this stuff shipped tomorrow, and I'm not getting any attaboys for finding problems at this stage. So what I mean is.... I'm on the Source Selection project, and that disagree stuff is... well not my problem. It's not. I can't do everything. Right? Right!!?? Right.

I find you scenario chillingly plausible... but I think your narrative "Boeing engineers knew about it, but not senior management!" is simplistic: a company like Boeing is much more complex than just two tiers, and while I can believe the C-level was plausibly unaware of the details best left unsaid in the boardroom, a lot of specific decisions cannot be ascribed to single engineers with a "not my problem" attitude (which, in and of itself, is a huge problem for an engineering company). For example:
* why Boeing decided to rewire the function of the STAB TRIM CUTOUT switches for the MAX?
* why this functional change was presented to FAA and the pilots as a simple re-labeling?
* why all mentions of MCAS were purged from the FCOM (except in the acronym list at the back, providing us with evidence that MCAS was at some point present in the revision history)
All of this smells very much of "can do" middle management with little understanding of causal chains.

sgrow787 wrote:

(1) New News: AOA Disagree Alert logic was not working correctly (turns off when the logic detects AOA option not installed). Boeing engineers (but not senior management!) knew about it a year before the first crash but didn't tell anybody about it.
(2) If Source Selection logic is triggered by the Disagree logic, then .... is this now a possible root cause for incorrect trigger of MCAS in both accidents?

Code: Select all

Disagree? -----yes----> Source Selection -----> Use good AOA sensor (discarding bad)
Disagree? -----no ----> Use onside AOA sensor (hey we don't have a disagree, so AOA-onside must be good if it doesn't disagree with AOA-offside) ----> let's use AOA-onside even if it may be bad** ----> CRASH

So all that Disagree logic (threshold and hysteresis logic) and all that Source Selection logic (to determine which sensor is good) goes down the drain (ie not used) because someone tied in (at the last minute?) an AOA install option. Which in their minds would have to mean "hey, if you don't think you need this option, well then you better have some really good pilots to deal with what we're gonna give you next".

**Wait, I didn't mean to say that. I didn't. I meant to say, hey, we put alot of resources into that Disagree logic when I was on the team. I know it works. Besides why would they screw that up? Anyway, they need this stuff shipped tomorrow, and I'm not getting any attaboys for finding problems at this stage. So what I mean is.... I'm on the Source Selection project, and that disagree stuff is... well not my problem. It's not. I can't do everything. Right? Right!!?? Right.

I think you are conflating the FCC and PFD that are entirely separate. The PFD will not be commanding the FCC to only perform those tasks it wishes to display the output of!

Ray

FluidFlow wrote:

seahawk wrote:

The airpseed unreliable checklist for the 737 has been criticized more than once in the past:

For example:
http://www.aaiu.ie/sites/default/files/ ... 13-017.pdf

And here is a QRH handbook for a NG http://www.737ng.co.uk/737-800%20Quick% ... QRH%29.pdf

Look at part 10.1

In addition you want to look at the performance section "Flight With Unreliable Airspeed - Climb", which says "Flaps Up, Set Max Climb Thrust"

From the report:

The Boeing Aircraft Company B737NG QRH checklists should provide
guidance for flight crew specifying the systems that might be affected
and the possible warnings generated as a consequence of a pitot
failure

Does someone on here has the QRH for the MAX in case of a AoA sensor failure?

And if so, is it lacking information for the pilots as well, especially regarding MCAS?

So. Are yous guys subtly suggesting that the absolute absolutes of what the pilots of all four flights should have been doing, that we have been pressed with several times a day for the last weeks, are not so absolute after all? They were not just all plain wrong with no feasible way to explain their actions?

Are you pointing out that having established that single side stick shaker is not indication of impending stall, following Unreliable Airspeed QRH climb with flaps up, max climb thrust is an appropriate action?

Thanks.
Ray

OldAeroGuy wrote:

smaragdz wrote:

OldAeroGuy wrote:

Yes, they could have gone to the "Airspeed Unreliable" drill immediately at Flaps 5 if they were willing to do it at about 1000' AGL. Cutting thrust back to 80% N1 and setting pitch at 10 deg would have kept them from overrunning the Flaps 5 placard

It was an option and part of good "Airmanship".

All the while battling with increasing nose down trim in a very rapidly devoloping situation, and with training that was specifically and intentionally withheld from them . I think it is unfair to place all these factors in a crew’s hands and then say they were lacking good airmanship. There is only so far that you can reasonably expect to push a human being. Remember that when it came to the NG the airmanship of these crews was by and large sufficient to operate that aircraft without any issue. is there room to learn from the crews actions? Always! And their actions will form a part of the investigations. But thinking that their actions are front and centre at the cause of this tragedy is choosing to ignore the massive elephant in the room.

You need to rethink this paragraph.

At Flaps 5 (or any other Flaps down setting), MCAS is not active. There would have been no increasing nose down trim.

Nose down trim only started when Flaps were retracted and MCAS began to trim nose down due to the erroneous AoA signal.

If you read my prior posts, the ET crew "Airmanship" issue is tied to their decision to retract Flaps with an active stick shaker, contrary to Boeing procedure.

I don't know if this was discussed in previous posts/threads, if so, then please excuse me but isn't the contention to the point regarding of not following the IAS Disagree checklist, the lack of the alert itself? The prelim never sighted an IAS Disagree alert indication, therefore, maybe why the crew didn't follow suit right away?

Or are you basing your assertion on the fact that a stick shaker should be adequate enough to follow that procedure?

The FAA and other around the world agencies could agree to lift the grounding in stages. All agencies could agree and work on other certifications. One obvious change is establishing necessary training for pilots. US goes first, and other agencies participate in monitoring. It does not have to be contentious.

Boeing and the FAA need to work extra overtime to correct the wrongs that led to this. No plane, redesigned or new design, should ever leave the ground for human passenger purposes without a full testing regimen completed and certified. I believe this should be the standard everywhere on the planet.

Amexair wrote:

OldAeroGuy wrote:

smaragdz wrote:

All the while battling with increasing nose down trim in a very rapidly devoloping situation, and with training that was specifically and intentionally withheld from them . I think it is unfair to place all these factors in a crew’s hands and then say they were lacking good airmanship. There is only so far that you can reasonably expect to push a human being. Remember that when it came to the NG the airmanship of these crews was by and large sufficient to operate that aircraft without any issue. is there room to learn from the crews actions? Always! And their actions will form a part of the investigations. But thinking that their actions are front and centre at the cause of this tragedy is choosing to ignore the massive elephant in the room.

You need to rethink this paragraph.

At Flaps 5 (or any other Flaps down setting), MCAS is not active. There would have been no increasing nose down trim.

Nose down trim only started when Flaps were retracted and MCAS began to trim nose down due to the erroneous AoA signal.

If you read my prior posts, the ET crew "Airmanship" issue is tied to their decision to retract Flaps with an active stick shaker, contrary to Boeing procedure.

I don't know if this was discussed in previous posts/threads, if so, then please excuse me but isn't the contention to the point regarding of not following the IAS Disagree checklist, the lack of the alert itself? The prelim never sighted an IAS Disagree alert indication, therefore, maybe why the crew didn't follow suit right away?

Or are you basing your assertion on the fact that a stick shaker should be adequate enough to follow that procedure?

I think that we'll need to wait for a full report to see what Alerts were triggered.

From the traces, it appears that the L/R Airspeed Indicators differed by 10-15 KIAS and the L/R Altimeters by >500' when Flaps up was selected.. This should have triggered both Airspeed Unreliable and Altitude Disagree Alerts.

The stick shaker alone would have been a cue.