aerolimani wrote:

But, this is pretty wild speculation. Perhaps not 100% outside the realm of possibility, but still unlikely, if purely for reasons of too big to fail.

Yes, I have to agree with Amiga500's nonquantification as "slim, but non-zero." I think there are a lot of really smart people at Boeing who will figure out a way out of this without painting themselves into a corner...

...but I am equipped with an imagination.

There must be a reason why Boeing and the FAA didn't tell airlines about the MCAS system and I don't think it is because of profits like what some people might say. They must have decided that the change between the NG and the MAX must not be that drastic that it warrants pilots to know. I still don't think the MCAS is the cause of the accident but it definitely did play some part in it, something that both Boeing and the FAA didn't realize that cause the MCAS to activate.

PW100 wrote:

peterinlisbon wrote:

LTC8K6 wrote:

It's not that simple. I think MCAS goes in steps. It makes an adjustment, 2.5 degrees I believe. If the stall conditions persist, it makes another 2.5 degree adjustment. And so on.

The problem is that if the sensor is faulty or damaged, it will keep on making 2.5 degree adjustments until the aircraft crashes into the ground.

In the Lion Air crash, the pilots could (and did) successfully re-trim each time the system made a 2.5 degree adjustment with an opposite 2.5 adjustment, presumably through trim switch on the control column. Four or five consecutive 2.5 degree trimming actions (without counter trimming) will put the elevator in a position overriding maximum control column authority. In the Lion crash, the pilots did something like 20+ counter actions, before the elevator went to max trimming. We still don't know why the pilots did/could not counteract that last trimming action(s).

Most important question - what happened after 20 trims. The 2 black boxes should have the answer by now.
I think they tried to turn and the speed drop made the plane uncontrollable as the AOA system which was already pushing the nose down and increasing speed erroneously, thought that stall is imminent and increased the speed and pushed the nose down drastically.
That's why both planes had nearly vertical drops with engines at high throttle.

Kinetic wrote:

Have to revise: According to FR24 ET302 made it to 8600 ft

How about actually reading the thread, rather that continiously filling it with nonsence that has been covered in great detail (all your points sofar) in umpteen posts in this very thread!

cougar15 wrote:

Kinetic wrote:

Have to revise: According to FR24 ET302 made it to 8600 ft

How about actually reading the thread, rather that continiously filling it with nonsence that has been covered in great detail (all your points sofar) in umpteen posts in this very thread!

How about reading all my replies to it?
Just kidding.
You are right, I was repeating issues which are none. At the same time I feel that they are not fully answered.

(and we all know they are not, by now (3/16/19))

PixelPilot wrote:

"Sully's" opinion:
https://www.foxnews.com/us/hero-pilot-w ... ines-crash

Got to love some of the comments on that story, even after knowing that Boeing have been in the process of implementing a fix for months:

User1: There are ZERO problems with the aircraft;

User2: Boeing didn't even tell the airline customers or their pilots about the MCAS. Now the code is proving to be "buggy".

User1: sorry bud, I have an avionics shop and have been involved in aviation all of my life.

User2: Well, you know a lot about avionics. But as an ex- USAF pilot with a combat tour and as a retired captain for a major airline, with 18,000 hours and zero incidents or accidents, I know a lot about flying the aircraft.

Also interesting that the article starts with (fair use excerpt):

"'It has been obvious since the Lion Air crash that a redesign of the 737 MAX 8 has been urgently needed, yet has still not been done, and the announced proposed fixes do not go far enough,' Sullenberger wrote."

yet the headline would lead one to believe that it is the flight hours of the F/O that are the sole cause of the crash.

9Patch wrote:

Interested wrote:

When I've seen comments about the lack of ability of the pilots in both crashes - people have mentioned their flights were in daylight and good weather so they should have been able to visually fly the plane and make the adjustments needed etc that way

Which clearly suggests that if it had been night time or bad weather that wouldn't be an option

So are we describing a plane that we accept might be safer for pilots to just fly during nice weather and daylight

Is that what we've come to with this plane?

Isn't every plane whether it's made by Boeing, Airbus, Embraer, Comac, etc., safer to fly during nice weather?

My point is the posts suggest the 737max becomes unsafe to fly at night or in bad weather. There's a big difference. Not so easy for the pilots to know what's going on and intervene when needed?

Amiga500 wrote:

phugoid1982 wrote:

I was wondering whether FAR 25.203 compliance was contingent upon Unaugmented Stability & Control characteristics when I happened upon 26.672b and 26.671

25.672 Stability augmentation and automatic and power-operated systems.
If the functioning of stability augmentation or other automatic or power-operated systems is necessary to show compliance with the flight characteristics requirements of this part, such systems must comply with §25.671 and the following:

(b) The design of the stability augmentation system or of any other automatic or power-operated system must permit initial counteraction of failures of the type specified in §25.671(c) without requiring exceptional pilot skill or strength, [b] by either the deactivation of the system, or a failed portion thereof, or by overriding the failure by movement of the flight controls in the normal sense.
[/b]

To throw another spanner in the works. It has been brought to my attention that 25.672 did not exist when the 737 was first certified. Can Boeing use it and retain grandfathering over the rest of the associated systems?

Yes, this is exactly the point here, grandfathering does not allow them to introduce new systems like stability augmentation onto the 737 a plane certified before the regulation existed but they have, also as the regulation didn't exist and therefore does not apply to the Boeing 737 Boeing technically don't have to build whatever they add to the 737 to be in compliance with it, which clearly they have not. This of course is one of the reasons why they can't add new systems to a grandfathered design yet the FAA waved it through so EASA had to eat it too under the reciprocal certification agreement.

I predict that this will be a huge problem for Boeing with EASA if not the FAA, congress should hold hearings and ask the (acting) head of the FAA to explain how the FAA allowed this to happen.

DocLightning wrote:

Amiga500 wrote:

It is dawning on me that there is a slim but non-zero possibility that the 737max may never be cleared to operate again - unless Boeing are allowed to do something no other aircraft has been under FAR25. The FAA might buy off on it, but really dunno how that will go down across the rest of the world.

This has occurred to me, too. They might have to step so far back into the design that it might go outside the boundaries of certification for the type. To make it worse, I understand that the FAA will not certify any more 737 derivatives.

I hope not, because the lead time on a clean-sheet design would be years and Airbus simply can't build enough A320NEOs and A220s to cover the 737 backlog. Ooof, what a mess that would be.

Uh oh. I never even thought about that this could be a scenario.

DocLightning wrote:

Amiga500 wrote:

It is dawning on me that there is a slim but non-zero possibility that the 737max may never be cleared to operate again - unless Boeing are allowed to do something no other aircraft has been under FAR25. The FAA might buy off on it, but really dunno how that will go down across the rest of the world.

This has occurred to me, too. They might have to step so far back into the design that it might go outside the boundaries of certification for the type. To make it worse, I understand that the FAA will not certify any more 737 derivatives.

I hope not, because the lead time on a clean-sheet design would be years and Airbus simply can't build enough A320NEOs and A220s to cover the 737 backlog. Ooof, what a mess that would be.

I think Boeing would have to keep the 737 NG in production in the interim. It is an exemplary aeroplane and who knows what continuing engine issues the 320 NEO might have?

I may be wrong here, but something I haven't seen mentioned so far is that - at least to a non-professional such as me - it appears to me that Boeing have been deliberately misleading from the start with the name 'MCAS'. 'Maneuvering Characteristics Augmentation System' sounds like it should be something that improves the maneuverability of the aircraft, whereas its real purpose is something that prevents an unstable condition at the edge of the flight envelope becoming dangerous.

Suppose they had called it something like, say 'Edge of Envelope Stall Protection' (EESP) instead, would it not have been more obvious to the FAA, airlines and pilots what it was for and when it might be trying to do something? And most importantly, what the consequences of turning it off might be. Or was disguising its real purpose the intention, in order not to draw attention to the potentially dangerous handling characteristics at high angles of attack?

There is a slim chance the MAX won't fly again. Boeing need to come up with a plan B to downgrade the frames already built and those in service back to NG standard. Otherwise they will have around 500 MAX frames to pay for and replace. No company could survive that! They also need to probably reboot NG production now just in case. I don't think a software fix to the MAX will ever work or get certified as safe.

peterinlisbon wrote:

LTC8K6 wrote:

decoder wrote:

So technically, the MCAS has the authority to crank the elevator jackscrew up against the stops, leaving pilots with an unrecoverable hardover? Maybe I'm not understanding something, because several of the engineering decisions made with this aircraft seem questionable at best.

It's not that simple. I think MCAS goes in steps. It makes an adjustment, 2.5 degrees I believe. If the stall conditions persist, it makes another 2.5 degree adjustment. And so on.

The problem is that if the sensor is faulty or damaged, it will keep on making 2.5 degree adjustments until the aircraft crashes into the ground.

Why would the pilots not just turn it off after two or three cycles though? As the one Lion Air crew did.

Why would you continue to fight with it if it's acting strange? Turning off the electric trim is not a new procedure, is it? Prior to the MAX, I mean. If it gave trouble, you could turn it off and go manual.

uta999 wrote:

There is a slim chance the MAX won't fly again. Boeing need to come up with a plan B to downgrade the frames already built and those in service back to NG standard. Otherwise they will have around 500 MAX frames to pay for and replace. No company could survive that! They also need to probably reboot NG production now just in case. I don't think a software fix to the MAX will ever work or get certified as safe.

IIRC they just announced that the fix will roll out in 10 days.

Virtual737 wrote:

PixelPilot wrote:

"Sully's" opinion:
https://www.foxnews.com/us/hero-pilot-w ... ines-crash

Got to love some of the comments on that story, even after knowing that Boeing have been in the process of implementing a fix for months:

User1: There are ZERO problems with the aircraft;

User2: Boeing didn't even tell the airline customers or their pilots about the MCAS. Now the code is proving to be "buggy".

User1: sorry bud, I have an avionics shop and have been involved in aviation all of my life.

User2: Well, you know a lot about avionics. But as an ex- USAF pilot with a combat tour and as a retired captain for a major airline, with 18,000 hours and zero incidents or accidents, I know a lot about flying the aircraft.

Also interesting that the article starts with (fair use excerpt):

"'It has been obvious since the Lion Air crash that a redesign of the 737 MAX 8 has been urgently needed, yet has still not been done, and the announced proposed fixes do not go far enough,' Sullenberger wrote."

yet the headline would lead one to believe that it is the flight hours of the F/O that are the sole cause of the crash.

That is kind of normal though.

Us engineers see the pilots as prone to failure and a potential risk for out perfectly designed airplane, pilots see the plane a a potential risk and prone to failure while they are the skilled aviators that will save the plane badly designed by the engineers. It has to be that way for the safety of the passengers.

LTC8K6 wrote:

uta999 wrote:

There is a slim chance the MAX won't fly again. Boeing need to come up with a plan B to downgrade the frames already built and those in service back to NG standard. Otherwise they will have around 500 MAX frames to pay for and replace. No company could survive that! They also need to probably reboot NG production now just in case. I don't think a software fix to the MAX will ever work or get certified as safe.

IIRC they just announced that the fix will roll out in 10 days.

After it rolls out it must be tested also and... I fear not only by Boeing/FAA.

That is the main issue in my opinion, the Boeing/FAA credibility has been lowered because in current situation MAX is not safely flyable by average ATPL pilot as the NG is.
The national agencies, airlines, pilots and travellers will ask for a trustworthy new certification.

In the article, called “Can Boeing Trust Pilots?,” McClellan writes:

What’s critical to the current, mostly uninformed discussion is that the 737 MAX system is not triply redundant. In other words, it can be expected to fail more frequently than one in a billion flights, which is the certification standard for flight critical systems and structures.

What Boeing is doing is using the age-old concept of using the human pilots as a critical element of the system ... In all airplanes I know of, the recovery is—including the 737 MAX—to shut off the system using buttons on the control wheel then a switch, or sometimes circuit breaker to make a positive disconnect.

Though the pitch system in the MAX is somewhat new, the pilot actions after a failure are exactly the same as would be for a runaway trim in any 737 built since the 1960s. As pilots we really don’t need to know why the trim is running away, but we must know, and practice, how to disable it.

Boeing is now faced with the difficult task of explaining to the media why pilots must know how to intervene after a system failure. And also to explain that airplanes have been built and certified this way for many decades. Pilots have been the last line of defense when things go wrong ...

But airline accidents have become so rare I’m not sure what is still acceptable to the flying public. When Boeing says truthfully and accurately that pilots need only do what they have been trained to do for decades when a system fails, is that enough to satisfy the flying public and the media frenzy?

The above is questioning why pilots are having to intervene and whether it's acceptable. I've also found 6 reports from US pilots with concerns about the 737 max which I will post one at a time for you guys to analyse

These are US pilots complaining about training and understanding issues about these planes. Not third world pilots. Imagine how many more similar issues will have occurred not counting US pilots.

It doesn't make good reading. And these are US pilots who have taken time and effort to file these concerns. How many weren't happy but didn't file a concern?

I had my first flight on the Max [to] ZZZ1. We found out we were scheduled to fly the aircraft on the way to the airport in the limo. We had a little time [to] review the essentials in the car. Otherwise we would have walked onto the plane cold.

My post flight evaluation is that we lacked the knowledge to operate the aircraft in all weather and aircraft states safely. The instrumentation is completely different - My scan was degraded, slow and labored having had no experience w/ the new ND (Navigation Display) and ADI (Attitude Director Indicator) presentations/format or functions (manipulation between the screens and systems pages were not provided in training materials. If they were, I had no recollection of that material).

We were unable to navigate to systems pages and lacked the knowledge of what systems information was available to us in the different phases of flight. Our weather radar competency was inadequate to safely navigate significant weather on that dark and stormy night. These are just a few issues that were not addressed in our training.

I recommend the following to help crews w/ their introductory flight on the Max:
Email notification the day before the flight (the email should include: Links - Training Video, PSOB and QRG and all relevant updates/FAQ's)
SME (Subject Matter Expert) Observer - the role of the SME is to introduce systems navigation, display management, answer general questions and provide standardized best practices to the next generation aircraft.

Additionally, the SME will collect de-identified data to provide to the training department for analysis and dissemination to the line pilots regarding FAQs and know systems differences as well best practices in fly the new model aircraft.

Synopsis

B737 MAX First Officer reported feeling unprepared for first flight in the MAX, citing inadequate training.

After 1000 feet I noticed a decrease in aircraft performance. I picked up that the autothrottles were not moving to commanded position even though they were engaged. I'm sure they were set properly for takeoff but not sure when the discrepancy took place. My scan wasn't as well developed since I've only flown the MAX once before. I manually positioned the thrust levers ASAP. This resolved the threat, we were able to increase speed to clean up and continue the climb to 3000 feet.

Shortly afterwards I heard about the (other carrier) accident and am wondering if any other crews have experienced similar incidents with the autothrottle system on the MAX? Or I may have made a possible flying mistake which is more likely. The FO (First Officer) was still on his first month and was not able to identify whether it was the aircraft or me that was in error.

Synopsis

B737-MAX8 Captain reported the autothrottles failed to move to the commanded position during takeoff and climb.

ACN: 1597380

Time / Day

Date : 201811

Place

Locale Reference.ATC Facility : ZZZ.TRACON
State Reference : US
Altitude.MSL.Single Value : 2000

Environment

Weather Elements / Visibility : Rain
Weather Elements / Visibility : Snow

Aircraft

Reference : X
ATC / Advisory.TRACON : ZZZ
Aircraft Operator : Air Carrier
Make Model Name : B737-800
Crew Size.Number Of Crew : 2
Operating Under FAR Part : Part 121
Flight Plan : IFR
Mission : Passenger
Nav In Use : FMS Or FMC
Flight Phase : Climb
Airspace.Class B : ZZZ

Component

Aircraft Component : Autoflight System
Aircraft Reference : X
Problem : Malfunctioning

Person

Reference : 1
Location Of Person.Aircraft : X
Location In Aircraft : Flight Deck
Reporter Organization : Air Carrier
Function.Flight Crew : Captain
Function.Flight Crew : Pilot Flying
Qualification.Flight Crew : Instrument
Qualification.Flight Crew : Air Transport Pilot (ATP)
Qualification.Flight Crew : Multiengine
Experience.Flight Crew.Last 90 Days : 626
ASRS Report Number.Accession Number : 1597380
Human Factors : Human-Machine Interface
Human Factors : Confusion

Events

Anomaly.Aircraft Equipment Problem : Less Severe
Detector.Automation : Aircraft Other Automation
Detector.Person : Flight Crew
When Detected : In-flight
Result.Flight Crew : FLC Overrode Automation
Result.Flight Crew : Overcame Equipment Problem
Result.Aircraft : Equipment Problem Dissipated

Assessments

Contributing Factors / Situations : Aircraft
Contributing Factors / Situations : Human Factors
Primary Problem : Aircraft

Narrative: 1

It was day three of six for me and day three with very good FO (First Officer). Well rested, great rapport and above average Crew coordination. Knew we had a MAX. It was my leg, normal Ops Brief, plus I briefed our concerns with the MAX issues, bulletin, MCAS, stab trim cutout response etc. I mentioned I would engage autopilot sooner than usual (I generally hand fly to at least above 10,000 ft.) to remove the possible MCAS threat.

Weather was about 1000 OVC drizzle, temperature dropping and an occasional snow flake. I double checked with an additional personal walkaround just prior to push; a few drops of water on the aircraft but clean aircraft, no deice required. Strong crosswind and I asked Tug Driver to push a little more tail east so as not to have slow/hung start gusts 30+.

Wind and mechanical turbulence was noted. Careful engine warm times, normal flaps 5 takeoff in strong (appeared almost direct) crosswind. Departure was normal. Takeoff and climb in light to moderate turbulence. After flaps 1 to "up" and above clean "MASI up speed" with LNAV engaged I looked at and engaged A Autopilot. As I was returning to my PFD (Primary Flight Display) PM (Pilot Monitoring) called "DESCENDING" followed by almost an immediate: "DONT SINK DONT SINK!"

I immediately disconnected AP (Autopilot) (it WAS engaged as we got full horn etc.) and resumed climb. Now, I would generally assume it was my automation error, i.e., aircraft was trying to acquire a miss-commanded speed/no autothrottles, crossing restriction etc., but frankly neither of us could find an inappropriate setup error (not to say there wasn't one).

With the concerns with the MAX 8 nose down stuff, we both thought it appropriate to bring it to your attention. We discussed issue at length over the course of the return to ZZZ. Best guess from me is airspeed fluctuation due to mechanical shear/frontal passage that overwhelmed automation temporarily or something incorrectly setup in MCP (Mode Control Panel). PM's callout on "descending" was particularly quick and welcome as I was just coming back to my display after looking away. System and procedures coupled with CRM (Resource Management) trapped and mitigated issue.

Synopsis

B737MAX Captain reported an autopilot anomaly in which led to an undesired brief nose down situation.

Interested wrote:

In the article, called “Can Boeing Trust Pilots?,” McClellan writes:
.....$why the MAX is a pilot higher demand airframe..............................

The PR machine is accelerating. starting to create a shock cone. ))))

I was well rested and had discussed the recent MAX 8 MCAS guidance with the Captain. On departure, we had strong crosswinds (gusts > 30 knots) directly off the right wing, however, no LLWS or Micro-burst activity was reported at the field. After verifying LNAV, selecting gear and flaps up, I set "UP" speed. The aircraft accelerated normally and the Captain engaged the "A" autopilot after reaching set speed. Within two to three seconds the aircraft pitched nose down bringing the VSI to approximately 1,200 to 1,500 FPM. I called "descending" just prior to the GPWS sounding "don't sink, don't sink." The Captain immediately disconnected the autopilot and pitched into a climb. The remainder of the flight was uneventful. We discussed the departure at length and I reviewed in my mind our automation setup and flight profile but can't think of any reason the aircraft would pitch nose down so aggressively.

Synopsis

B737 MAX First Officer reported that the aircraft pitched nose down after engaging autopilot on departure. Autopilot was disconnected and flight continued to destination.

ACN: 1593021

Time / Day

Date : 201811

Place

Altitude.AGL.Single Value : 0

Aircraft

Reference : X
Aircraft Operator : Air Carrier
Make Model Name : B737 Next Generation Undifferentiated
Crew Size.Number Of Crew : 2
Operating Under FAR Part : Part 121
Flight Plan : IFR
Flight Phase : Parked

Person

Reference : 1
Location Of Person.Aircraft : X
Location In Aircraft : Flight Deck
Reporter Organization : Air Carrier
Function.Flight Crew : Captain
Qualification.Flight Crew : Instrument
Qualification.Flight Crew : Air Transport Pilot (ATP)
Qualification.Flight Crew : Multiengine
Experience.Flight Crew.Total : 21200
Experience.Flight Crew.Last 90 Days : 178
Experience.Flight Crew.Type : 3342
ASRS Report Number.Accession Number : 1593021
Human Factors : Training / Qualification
Human Factors : Confusion

Events

Anomaly.Deviation - Procedural : Published Material / Policy
Detector.Person : Flight Crew
When Detected : Pre-flight
Result.General : None Reported / Taken

Assessments

Contributing Factors / Situations : Company Policy
Contributing Factors / Situations : Human Factors
Contributing Factors / Situations : Manuals
Contributing Factors / Situations : Procedure
Primary Problem : Manuals

Narrative: 1

This was the first flight on a Max for both pilots. Unfamiliarity with flight deck displays led to confusion about display annunciations and switch function. The Flight Manual does not address at least one annunciation, or the controls for the display—or if it does, neither pilot could find the explanation. I have spent literally days looking for an explanation, could not find one, and that is why I wrote this report. It shouldn't be this hard to figure out what I'm looking at.

On the First Officer side ND, on the ground only, there is a MAINT annunciation. We both saw it, couldn't find any immediate explanation for it on the ground, and didn't address it until airborne. I researched the FM (Flight Manual) for an explanation, accomplishing a word search of the term MAINT. There are only two references I could find: the overhead MAINT light (a no go item) and the CDS MAINT light (a QRH item). There is no explanation of the ND MAINT annunciation.

We spent the entire hour flight trying to find the meaning of this annunciation and came up empty handed. We determined to check it out once we landed (if the light came on again). Sure enough, after parking, the MAINT annunciation came back on the ND display. We called Maintenance to check out the light. We waited to make an ELB entry, unsure if one was required. Turned out, an ELB entry was not required.

The mechanic explained the light was part of a menu for maintenance use only on the ground.

In addition, there are two selector knobs that are under-explained (i.e., not explained) in the manual, and we were uncertain what their purpose was. One is under the Fuel Flow switch and the other under the MFD/ENG TFR display switch. These knobs don't seem to work in flight. The First Officer offered to hit the SEL function in flight, to test it out, but I thought something irreversible or undesirable might happen (not knowing what we were actually selecting), so we did not try it out in flight. The mechanic later explained SEL on the First Officer side was used on the ground by maintenance to toggle between the maintenance functions. I forgot to ask what my side did, and still don't know.

Finally, in the Captain's preflight procedure in the bulletin, it says, "Selector... C". What selector is this referring to? Is this the same selector under the Fuel Flow switch, (which is shown in the MAX panels on the L position, as if that is the normal position?) This is very poorly explained. I have no idea what switch the preflight is talking about, nor do I understand even now what this switch does.

I think this entire setup needs to be thoroughly explained to pilots. How can a Captain not know what switch is meant during a preflight setup? Poor training and even poorer documentation, that is how.

It is not reassuring when a light cannot be explained or understood by the pilots, even after referencing their flight manuals. It is especially concerning when every other MAINT annunciation means something bad. I envision some delayed departures as conscientious pilots try to resolve the meaning of the MAINT annunciation and which switches are referred to in the setup.

Synopsis

B737MAX Captain reported confusion regarding switch function and display annunciations related to "poor training and even poorer documentation".

4) This is the harshest-judgment report, in which the captain condemns Boeing for the insufficiency of the documentation. ASRS summary: “B737MAX Captain expressed concern that some systems such as the MCAS are not fully described in the aircraft Flight Manual.”

ACN: 1593017

Time / Day

Date : 201811

Place

Altitude.AGL.Single Value : 0

Aircraft

Reference : X
Aircraft Operator : Air Carrier
Make Model Name : B737 Next Generation Undifferentiated
Flight Phase.Other

Person

Reference : 1
Location Of Person.Aircraft : X
Location In Aircraft : Flight Deck
Reporter Organization : Air Carrier
Function.Flight Crew : Captain
Qualification.Flight Crew : Air Transport Pilot (ATP)
ASRS Report Number.Accession Number : 1593017
Human Factors : Confusion
Human Factors : Training / Qualification

Events

Anomaly.Deviation - Procedural : Published Material / Policy
Detector.Person : Flight Crew
When Detected : Pre-flight
Result.General : None Reported / Taken

Assessments

Contributing Factors / Situations : Aircraft
Contributing Factors / Situations : Manuals
Primary Problem : Manuals

Narrative: 1

The recently released 737 MAX8 Emergency Airworthiness Directive directs pilots how to deal with a known issue, but it does nothing to address the systems issues with the AOA system.

MCAS (Maneuvering Characteristics Augmentation System) is implemented on the 737 MAX to enhance pitch characteristics with flaps UP and at elevated angles of attack. The MCAS function commands nose down stabilizer to enhance pitch characteristics during steep turns with elevated load factors and during flaps up flight at airspeeds approaching stall. MCAS is activated without pilot input and only operates in manual, flaps up flight. The system is designed to allow the flight crew to use column trim switch or stabilizer aisle stand cutout switches to override MCAS input. The function is commanded by the Flight Control computer using input data from sensors and other airplane systems.

The MCAS function becomes active when the airplane Angle of Attack exceeds a threshold based on airspeed and altitude. Stabilizer incremental commands are limited to 2.5 degrees and are provided at a rate of 0.27 degrees per second. The magnitude of the stabilizer input is lower at high Mach number and greater at low Mach numbers. The function is reset once angle of attack falls below the Angle of Attack threshold or if manual stabilizer commands are provided by the flight crew. If the original elevated AOA condition persists, the MCAS function commands another incremental stabilizer nose down command according to current aircraft Mach number at actuation.

This description is not currently in the 737 Flight Manual Part 2, nor the Boeing FCOM, though it will be added to them soon. This communication highlights that an entire system is not described in our Flight Manual. This system is now the subject of an AD.

I think it is unconscionable that a manufacturer, the FAA, and the airlines would have pilots flying an airplane without adequately training, or even providing available resources and sufficient documentation to understand the highly complex systems that differentiate this aircraft from prior models. The fact that this airplane requires such jury rigging to fly is a red flag. Now we know the systems employed are error prone--even if the pilots aren't sure what those systems are, what redundancies are in place, and failure modes.

I am left to wonder: what else don't I know? The Flight Manual is inadequate and almost criminally insufficient. All airlines that operate the MAX must insist that Boeing incorporate ALL systems in their manuals.

Synopsis

B737MAX Captain expressed concern that some systems such as the MCAS are not fully described in the aircraft Flight Manual.

That last one is damning isn't it?

The more I hear about the flying characteristics of the Max and the certification process - the more I think the industry standard safety approach has broken down.

This is not good news for anyone.

Aviation has got progressively safer. Now some seem set on risking that through the law of unintended consequences.

Interested wrote:

That last one is damning isn't it?

They all are to some extent. The other one that stuck out for me was (one of?) the first, which stated that the first time the pilot saw the MAX cockpit was when they entered it for his first revenue flight, and that they didn't know how the new displays worked even after reading all documentation available.

Virtual737 wrote:

Interested wrote:

That last one is damning isn't it?

They all are to some extent. The other one that stuck out for me was (one of?) the first, which stated that the first time the pilot saw the MAX cockpit was when they entered it for his first revenue flight, and that they didn't know how the new displays worked even after reading all documentation available.

Yes and this is US and clearly very conscientious pilots who really care and worry about delivering a safe flight. We likely don't get any better scenarios than this.

And these guys can't figure out what to do or feel well prepared to fly these planes safely. Even when some spend DAYS looking for answers in manuals the answers aren't there??

If US pilots are struggling in the very country that creates these planes what chance pilots in the rest of the world?

It's absolutely shocking stuff to read. It's just not what you expect.

Those reports must surely be embarrassing and totally unacceptable to Boeing senior management! Surely?

Interested wrote:

Those reports must surely be embarrassing and totally unacceptable to Boeing senior management! Surely?

Yep, thanks for posting them. I'm wondering how the MAX was able to share a type rating when even experienced US NG pilots didn't even know how the PRIMARY Flight Displays worked.

Virtual737 wrote:

Interested wrote:

Those reports must surely be embarrassing and totally unacceptable to Boeing senior management! Surely?

Yep, thanks for posting them. I'm wondering how the MAX was able to share a type rating when even experienced US NG pilots didn't even know how the PRIMARY Flight Displays worked.

It's scary stuff to read. Credit to the pilots who wrote those reports. I want them flying me. You can see the real desire for safety is within them. Shame others above them have let them down in so many ways. Training, manuals, systems - all three lacking. Clearly not just one software problem to fix here.

I find the most interesting part is that pilots experienced an uncommanded nose down motion with AP engaged, when MCAS description says the system is not active with AP engaged.

klm617 wrote:

ytz wrote:

ELBOB wrote:

We have to dumb-down aircraft handling because it's simply infeasible to skill-up every pilot to an extreme level. Even the military can't achieve that.

Boeing are obliged to ensure that their aircraft can be handled in all likely scenarios crew of average skill because the nature of humans means that, yes, most people are merely average at what they do.

If it transpires that the aircraft is too complex or difficult for an average crew to operate, the blame lies with the manufacturer and regulator. Otherwise it should have been put on an Experimental certificate and forbidden for commercial use.

And everyone should not that the definition talks about skill. Not hours or on what type those hours were earned on. A properly licensed pilot, qualified on type should be able to operate the jet safely. If it becomes absolutely necessary to have anything more than that to safely operate this aircraft, than the aircraft is not meeting design standards and should have its type certificate revoked.

Sorry it's on the airlines to get their crews up to speed when they order an aircraft. There is a market for such an aircraft so Boeing builds it. It's not like the Electra where the wing was falling of the crew has no control in recovering from that but erroneous computer readings is a survivable anomaly if you manually take over the aircraft. With computers there is always going to be system problems here and there but an adequately trained crew should be able to fly the aircraft out of danger.

So what you are saying is that it’s ok to do sloppy programming/design as long as you train the pilots to handle it when it fails, WHEN, not if? And if the pilot fails the aircraft manufacturer has no responsibility, only the airline?

JohnKrist wrote:

So what you are saying is that it’s ok to do sloppy programming/design as long as you train the pilots to handle it when it fails, WHEN, not if? And if the pilot fails the aircraft manufacturer has no responsibility, only the airline?

....and even better, don't tell the pilots that the system exists in the first place. If you're going to test their skill, you should really test it.

From those reports lack of training to fly the plane is as big a concern as any other issue

A US pilot suggesting a days notice if possible for anyone new to the plane they can swot up on these planes (by watching videos) in their own time before they fly them for the first time??

Truly Incredible state of affairs!!

I'm gobsmacked

journeyperson wrote:

DocLightning wrote:

Amiga500 wrote:

It is dawning on me that there is a slim but non-zero possibility that the 737max may never be cleared to operate again - unless Boeing are allowed to do something no other aircraft has been under FAR25. The FAA might buy off on it, but really dunno how that will go down across the rest of the world.

This has occurred to me, too. They might have to step so far back into the design that it might go outside the boundaries of certification for the type. To make it worse, I understand that the FAA will not certify any more 737 derivatives.

I hope not, because the lead time on a clean-sheet design would be years and Airbus simply can't build enough A320NEOs and A220s to cover the 737 backlog. Ooof, what a mess that would be.

I think Boeing would have to keep the 737 NG in production in the interim. It is an exemplary aeroplane and who knows what continuing engine issues the 320 NEO might have?

Well yeah, but who'll be taking them? Despite the lies Boeing has previously tried to spin, the NG isn't competitive with the NEO, so we'll have airlines flying the NEO and other airlines willingly taking a plane that's at least (and I'm probably being conservative here) ~5% less efficient?

But I guess in the very, very unlikely scenario the MAX never flies again, or isn't cleared to fly for a long time, airlines will weigh the extra cost of flying a relatively inefficient plane over the cost of getting in queue for the NEO or switching to Airbus.

crimsonchin wrote:

Well yeah, but who'll be taking them? Despite the lies Boeing has previously tried to spin, the NG isn't competitive with the NEO, so we'll have airlines flying the NEO and other airlines willingly taking a plane that's at least (and I'm probably being conservative here) ~5% less efficient?
.

If an airline already operates the 737NG and/or wants to buy a new airplane at sufficiently lower price compared to the NEO,Boeing can sell the NG. In the end, for the airlines it is a matter of total cost from purchase day to last day in the fleet.
Not sure if Boeing can sell more NG at sufficiently lower price while making profit.

Interested wrote:

4) This is the harshest-judgment report, in which the captain condemns Boeing for the insufficiency of the documentation. ASRS summary: “B737MAX Captain expressed concern that some systems such as the MCAS are not fully described in the aircraft Flight Manual.”

ACN: 1593017

Time / Day

Date : 201811

Place

Altitude.AGL.Single Value : 0

Aircraft

Reference : X
Aircraft Operator : Air Carrier
Make Model Name : B737 Next Generation Undifferentiated
Flight Phase.Other

Person

Reference : 1
Location Of Person.Aircraft : X
Location In Aircraft : Flight Deck
Reporter Organization : Air Carrier
Function.Flight Crew : Captain
Qualification.Flight Crew : Air Transport Pilot (ATP)
ASRS Report Number.Accession Number : 1593017
Human Factors : Confusion
Human Factors : Training / Qualification

Events

Anomaly.Deviation - Procedural : Published Material / Policy
Detector.Person : Flight Crew
When Detected : Pre-flight
Result.General : None Reported / Taken

Assessments

Contributing Factors / Situations : Aircraft
Contributing Factors / Situations : Manuals
Primary Problem : Manuals

Narrative: 1

The recently released 737 MAX8 Emergency Airworthiness Directive directs pilots how to deal with a known issue, but it does nothing to address the systems issues with the AOA system.

MCAS (Maneuvering Characteristics Augmentation System) is implemented on the 737 MAX to enhance pitch characteristics with flaps UP and at elevated angles of attack. The MCAS function commands nose down stabilizer to enhance pitch characteristics during steep turns with elevated load factors and during flaps up flight at airspeeds approaching stall. MCAS is activated without pilot input and only operates in manual, flaps up flight. The system is designed to allow the flight crew to use column trim switch or stabilizer aisle stand cutout switches to override MCAS input. The function is commanded by the Flight Control computer using input data from sensors and other airplane systems.

The MCAS function becomes active when the airplane Angle of Attack exceeds a threshold based on airspeed and altitude. Stabilizer incremental commands are limited to 2.5 degrees and are provided at a rate of 0.27 degrees per second. The magnitude of the stabilizer input is lower at high Mach number and greater at low Mach numbers. The function is reset once angle of attack falls below the Angle of Attack threshold or if manual stabilizer commands are provided by the flight crew. If the original elevated AOA condition persists, the MCAS function commands another incremental stabilizer nose down command according to current aircraft Mach number at actuation.

This description is not currently in the 737 Flight Manual Part 2, nor the Boeing FCOM, though it will be added to them soon. This communication highlights that an entire system is not described in our Flight Manual. This system is now the subject of an AD.

I think it is unconscionable that a manufacturer, the FAA, and the airlines would have pilots flying an airplane without adequately training, or even providing available resources and sufficient documentation to understand the highly complex systems that differentiate this aircraft from prior models. The fact that this airplane requires such jury rigging to fly is a red flag. Now we know the systems employed are error prone--even if the pilots aren't sure what those systems are, what redundancies are in place, and failure modes.

I am left to wonder: what else don't I know? The Flight Manual is inadequate and almost criminally insufficient. All airlines that operate the MAX must insist that Boeing incorporate ALL systems in their manuals.

Synopsis

B737MAX Captain expressed concern that some systems such as the MCAS are not fully described in the aircraft Flight Manual.

Thanks a bunch for posting that. Extremely useful feedback.

" The fact that this airplane requires such jury rigging to fly is a red flag."

Says it all....

phugoid1982 wrote:

Interested wrote:

4) This is the harshest-judgment report, in which the captain condemns Boeing for the insufficiency of the documentation. ASRS summary: “B737MAX Captain expressed concern that some systems such as the MCAS are not fully described in the aircraft Flight Manual.”

ACN: 1593017

Time / Day

Date : 201811

Place

Altitude.AGL.Single Value : 0

Aircraft

Reference : X
Aircraft Operator : Air Carrier
Make Model Name : B737 Next Generation Undifferentiated
Flight Phase.Other

Person

Reference : 1
Location Of Person.Aircraft : X
Location In Aircraft : Flight Deck
Reporter Organization : Air Carrier
Function.Flight Crew : Captain
Qualification.Flight Crew : Air Transport Pilot (ATP)
ASRS Report Number.Accession Number : 1593017
Human Factors : Confusion
Human Factors : Training / Qualification

Events

Anomaly.Deviation - Procedural : Published Material / Policy
Detector.Person : Flight Crew
When Detected : Pre-flight
Result.General : None Reported / Taken

Assessments

Contributing Factors / Situations : Aircraft
Contributing Factors / Situations : Manuals
Primary Problem : Manuals

Narrative: 1

The recently released 737 MAX8 Emergency Airworthiness Directive directs pilots how to deal with a known issue, but it does nothing to address the systems issues with the AOA system.

MCAS (Maneuvering Characteristics Augmentation System) is implemented on the 737 MAX to enhance pitch characteristics with flaps UP and at elevated angles of attack. The MCAS function commands nose down stabilizer to enhance pitch characteristics during steep turns with elevated load factors and during flaps up flight at airspeeds approaching stall. MCAS is activated without pilot input and only operates in manual, flaps up flight. The system is designed to allow the flight crew to use column trim switch or stabilizer aisle stand cutout switches to override MCAS input. The function is commanded by the Flight Control computer using input data from sensors and other airplane systems.

The MCAS function becomes active when the airplane Angle of Attack exceeds a threshold based on airspeed and altitude. Stabilizer incremental commands are limited to 2.5 degrees and are provided at a rate of 0.27 degrees per second. The magnitude of the stabilizer input is lower at high Mach number and greater at low Mach numbers. The function is reset once angle of attack falls below the Angle of Attack threshold or if manual stabilizer commands are provided by the flight crew. If the original elevated AOA condition persists, the MCAS function commands another incremental stabilizer nose down command according to current aircraft Mach number at actuation.

This description is not currently in the 737 Flight Manual Part 2, nor the Boeing FCOM, though it will be added to them soon. This communication highlights that an entire system is not described in our Flight Manual. This system is now the subject of an AD.

I think it is unconscionable that a manufacturer, the FAA, and the airlines would have pilots flying an airplane without adequately training, or even providing available resources and sufficient documentation to understand the highly complex systems that differentiate this aircraft from prior models. The fact that this airplane requires such jury rigging to fly is a red flag. Now we know the systems employed are error prone--even if the pilots aren't sure what those systems are, what redundancies are in place, and failure modes.

I am left to wonder: what else don't I know? The Flight Manual is inadequate and almost criminally insufficient. All airlines that operate the MAX must insist that Boeing incorporate ALL systems in their manuals.

Synopsis

B737MAX Captain expressed concern that some systems such as the MCAS are not fully described in the aircraft Flight Manual.

Thanks a bunch for posting that. Extremely useful feedback.

" The fact that this airplane requires such jury rigging to fly is a red flag."

Says it all....

I had to check the definition:

"Jury rigging is both a noun and a verb describing makeshift repairs made with only the tools and materials at hand. Its origin lies in such efforts done on boats and ships, characteristically sail powered to begin with. After a dismasting, a replacement mast and if necessary yard would be fashioned and stayed to allow a craft to resume making way."

We've gone primitive and makeshift

Interested wrote:

From those reports lack of training to fly the plane is as big a concern as any other issue

A US pilot suggesting a days notice if possible for anyone new to the plane they can swot up on these planes (by watching videos) in their own time before they fly them for the first time??

Truly Incredible state of affairs!!

I'm gobsmacked

Indeed. Does anyone who operates the NG and MAX have separate pilot groups for them? Obviously this isn’t an issue for carriers like AC with no other 737s but many if not lost MAX operators have large NG fleets too.

I wonder how much this differs from the introduction of NGs at carriers like CO and WN that had big Classic fleets at the time. Obviously the specific MCAS issue was absent but there certainly were differences.

Cubsrule wrote:

Interested wrote:

From those reports lack of training to fly the plane is as big a concern as any other issue

A US pilot suggesting a days notice if possible for anyone new to the plane they can swot up on these planes (by watching videos) in their own time before they fly them for the first time??

Truly Incredible state of affairs!!

I'm gobsmacked

Indeed. Does anyone who operates the NG and MAX have separate pilot groups for them? Obviously this isn’t an issue for carriers like AC with no other 737s but many if not lost MAX operators have large NG fleets too.

I wonder how much this differs from the introduction of NGs at carriers like CO and WN that had big Classic fleets at the time. Obviously the specific MCAS issue was absent but there certainly were differences.

They have new switches on the plane that the pilots don't know what they do, aren't in the manual and it turns out are purely for the benefit of ground crew and maintenance to use??

You couldn't make this up

seahawk wrote:

I find the most interesting part is that pilots experienced an uncommanded nose down motion with AP engaged, when MCAS description says the system is not active with AP engaged.

I noticed that as well. It seems MCAS has authority even in non-manual flight regime. The fact that when the pilots disconnected the AP MCAS did not continue pitching the nose down is also interesting. Either whatever anomaly the aircraft encountered was fleeting (momentary probe failure, SW failure), or manual control corrected something the AP wasn't aware of. The crosswind factor is interesting. I'm wondering if there is a an issue when the aircraft hits a crosswind and may be rolled slightly whilst the pilots/computer correct for roll induced by sideslip. Mathematically, AOA and sideslip angle are defined in such a way there is no ambiguity when the plane is rolled at an angle as to which is which. However, I wonder if there is an instrumentation error where during certain situations the Flight data computer may interpret sideslip as an increase in AOA or a SW glitch and thus feeding this to hydraulic actuators.

phugoid1982 wrote:

seahawk wrote:

I find the most interesting part is that pilots experienced an uncommanded nose down motion with AP engaged, when MCAS description says the system is not active with AP engaged.

I noticed that as well. It seems MCAS has authority even in non-manual flight regime. The fact that when the pilots disconnected the AP MCAS did not continue pitching the nose down is also interesting. Either whatever anomaly the aircraft encountered was fleeting (momentary probe failure, SW failure), or manual control corrected something the AP wasn't aware of. The crosswind factor is interesting. I'm wondering if there is a an issue when the aircraft hits a crosswind and may be rolled slightly whilst the pilots/computer correct for roll induced by sideslip. Mathematically, AOA and sideslip angle are defined in such a way there is no ambiguity when the plane is rolled at an angle as to which is which. However, I wonder if there is an instrumentation error where during certain situations the Flight data computer may interpret sideslip as an increase in AOA or a SW glitch and thus feeding this to hydraulic actuators.

I wonder how much money and hours has been thrown at investigating this particular report compared to the lion and Ethiopia air crash investigations

I wonder how much priority and focus a report like this gets

Or doesn't it count for much because nobody died?

And whilst these planes are grounded wouldn't it be a good time to train pilots across the world the differences in what the switches are and do. How stuff is supposed to work etc. So if the planes ever do fly again they don't just get thrown into them cold or feeling unprepared

Get them all on training courses. They clearly need them

This has always been a software issue. Some folks posting here are acting this plane needs a re-design, while saying Airbus can do this, this and this. Looks like that won't happen.

Also, didn't Airbus have their own issues with their aircraft too.

https://www.cnbc.com/2019/03/15/boeing- ... -days.html

JohnKrist wrote:

So what you are saying is that it’s ok to do sloppy programming/design as long as you train the pilots to handle it when it fails, WHEN, not if? And if the pilot fails the aircraft manufacturer has no responsibility, only the airline?

He laments the double whammy of
Bad design/execution (BAD) PLUS bad documentation ( BAD) ~= a new LOW.

in a way the synergy of badness.

indcwby wrote:

This has always been a software issue. Some folks posting here are acting this plane needs a re-design, while saying Airbus can do this, this and this. Looks like that won't happen.

Also, didn't Airbus have their own issues with their aircraft too.

https://www.cnbc.com/2019/03/15/boeing- ... -days.html

"The FAA set to sign off on Boeing 737 Max software fix in 10 days, shares rise"

Of the 10 days, how many of them are Boeing still working on the fix and how many of them are the FAA analysing and then signing it off? Or are they just rubber stamping what Boeing tell them again?

Interested wrote:

And whilst these planes are grounded wouldn't it be a good time to train pilots across the world the differences in what the switches are and do. How stuff is supposed to work etc. So if the planes ever do fly again they don't just get thrown into them cold or feeling unprepared

Get them all on training courses. They clearly need them

I wonder how much authority airlines have to ask for additional training without a mandate from the governing federal agency (FAA, EASA..etc) and whether it can be done individually at the discretion of the company. At what point when you start asking for training that diverges from what was used for certifcation do you have to go back and re-certify the aircraft?

phugoid1982 wrote:

Interested wrote:

And whilst these planes are grounded wouldn't it be a good time to train pilots across the world the differences in what the switches are and do. How stuff is supposed to work etc. So if the planes ever do fly again they don't just get thrown into them cold or feeling unprepared

Get them all on training courses. They clearly need them

I wonder how much authority airlines have to ask for additional training without a mandate from the governing federal agency (FAA, EASA..etc) and whether it can be done individually at the discretion of the company. At what point when you start asking for training that diverges from the NG does this delve into requiring a new type rating that can't be grandfathered in, irrespective of design changes?

Ive just read an article that says a huge selling point of these planes is that no new training was required.

It's like the pilots themselves feel they want to be trained and have to take it on themselves?