737 MAX

[FredK]

I was seriously starting to think about upgrading my 737NG to the MAX MIP format, but now I do not know if I want to risk death on takeoff.

Fred K

[Joe Lavery]

Very sad day for the passengers and crew of both of these aircraft. Also I was shocked when the CAA took the unprecedented decision to ban all flights to and from the UK by 737 Max aircraft.
So quite a difficult time for Boeing also until the cause of the crashes is determined.

[bernard S]

my 2 cents   if pilots do not have 100 percent operation control then ground it    ..Boeing going to fix it   software and training ..they fixed the battery issue in 78 and bounced back

[navymustang]

I'm getting a bit frustrated when the news folks don't gather correct data and start trying to blame Boeing for this entire mess. A runaway trim condition has several escape routes that most of you know. Why hasn't there been more discussion of poor piloting skills during these failures? Even with a control system that is not behaving - you can still get around the issue with proper emergency procedures.

Seems like airline training in the sim has been terribly miss-managed. I guess we need to sit back and see what evidence comes from the cockpit recorders.

[jfuenmayor]

Well, from what I have gathered so far, it seems that there are some issues with the
actual frame design  and the CG as a result of moving the engines forward, up an closer in the  old 737 fuselage type, in order be able to to place them them and clear the terrain. Increasing the height of the landing gear was an option but it would have also introduced major changes in the fuselage and wing to make room for the main gear wells.

The net effect of this modification seems to have been the tendency for the airplane to pitch up in an unusual way at full throttle, ergo, enter MCAS. It was developed precisely to correct for this and avoid stall situations. Some experts may think it is not a good idea to use software to compensate for native design. The  MCAS system does not fully deactivate when the autopilot is disconnected, and reactivates itself every 10 seconds despite repeated pilot commands to do so, and will continue to trim down to avoid what the computer thinks is an imminent stall condition. The fact that it seems to only use two AOA vanes as data feed for error checking seems puzzling. It is quite hard for me to believe that, but that is what is out there. Critics claim that other parameters should be used for cross checking.
I am sure the millions of lines of code involved in the software for these airplanes have been audited to exhaustion but, as I said, to compensate for an air frame design flaw with  software seems a bit far fetched.

It is also speculated that the reason why the MAX was not designed from the ground up to accommodate the newer bigger engines,  was not only to transition the crews from the NG to the MAX with minimum training, but also to avoid a full re certification process of the new air frame which, also meant time and money. I do not think the engineers did not foresee this scenario which could result in a very dangerous situation. This is quite hard for me to fathom, since their job entitles to think about the unthinkable and solve it. Quite hard to do actually, and that is why they have my admiration.

So picture yourselves at low altitude, confronted with a situation for which you are not prepared and which is totally contrary to what you would expect. An AA pilot related that his training in the MAX consisted of an iPad video of one hour. No sim time. As a matter of fact AA does not have a Sim for the MAX, so claims this pilot.

It would appear to me  that the Ethiopian crew should have been fully aware of the MCAS behavior, hell I was, and I do not fly for a living. Also, the scenario of a runaway stabilizer trim must have crossed their minds, if they had time. The purpose of training in general,  is to learn to react naturally and swiftly  to a situation, and not to have to come up with an elaborate solution when there is no time for that, such as in this case, may I observe. The shock would come if the  Ethiopian crew did indeed flip those switches to deactivate the trim motors, and yet they ended up crashing. It seems they got up to only 1400 feet above terrain. Note a heck of a lot.

I hope Boeing is able to get to the bottom of this and correct what seems to be a real issue. Two brand new planes crashing in similar circumstances.

A passenger airplane is not a fighter, and although pilots must fly the damned thing, they do not have to fight it.

My two cents.

[KyleH]

Ok we need to get some facts straight on this so we are not spreading additional miss information.

The MCAS system was required due to the change in placement of the engine, further forward from the wing on the pylon.
The 737 could not pass certification without the MCAS system because of a requirement that as you pull the yoke back the force on the yoke must not get lighter as you approach the end of it's travel, especially as you approach a stall. With the placement of the engines on the MAX, at high angles of attack and no flaps, the engines nacelles will begin to contribute some amount of lift, forcing the aircraft to continue pitching up, which resulted in the force required on the yoke to decrease as it approached a stall.

Imagine your a pilot, pulling back on the yoke approaching a stall with the control forces getting harder as they should, then the forces required get lighter resulting in you pulling it even faster into a stall.

The FAA would not certify the plane in this state. The MCAS system was designed to run the stab trim forward in this flight regime only, in order to maintain the same required control force on the column throughout the stall maneuver.
The system is supposed to only engage in the specific situation of: autopilot off, flaps up, and high angle of attack.
The FAA certified the plane with this system installed.

Now, the failure mode in the Lyon Air case is that the AOA sensor failed and the system thought it needed to run to prevent a stall, resulting in the stab trim to run forwards pitching the nose down.

My opinion;

I agree with Jim. This is a training issue that we are now dealing with due to the pilot shortage and having low time crews in these airplanes.

I feel it's important to note, that there are other failures that can cause the trim to runaway that have nothing to do with MCAS system, and could occur on any airplane with powered trim, not just the MAX. In fact the Lyon Air aircraft flew 3 times previously with the fault, and those crews successfully recovered the airplane.
The procedure to recover from this is the same no matter the cause of the failure. Those that have a motorized 737 throttle quadrant should know, it's hard to miss the indications of a trim runaway with those massive wheels running right beside your knee. Proper training and procedures is required to overcome these situations.

As far as the simulators go, there are very few MAX simulators in the world due to the common type ratting granted by the FAA. Only airlines that were not flying the NG have them.

And for the Ethiopian flight, all we have at this time is flight path data that shows a similar profile. We don't have any data yet to determine what went on in the cockpit. It could have been something unrelated to MCAS. I only hope that FAA and Transport Canada decisions to ground the MAX have some valid evidence that has not been released yet and not just giving into hysteria generated by the media on a complex issue that most are not capable of understanding.

Publishing a revised software 'fix' is not going to get to the root of the problem which is pilot skills, training and proficiency.

[KyleH]

For anyone interested, a summary of the events on the flight previous to the Lyon Air accident:

"About 400 feet, the PIC noticed on the Primary Flight Display (PFD)13 that the IAS DISAGREE warning appeared and the stick shaker activated. The FDR showed the stick shaker activated during the rotation. Following that indication, the PIC maintained a pitch of 15° and the existing takeoff thrust setting. The stick shaker remained active throughout the flight.

The PIC handed over control to the SIC and announced "memory item airspeed unreliable". After the transfer of control, the PIC cross checked the PFDs with the standby instrument and determined that the left PFD had the problem. The PIC then switched on the right flight director (FD) so the SIC would have a normal display.

While handling the problem, the PIC instructed the SIC to continue acceleration and flap retraction as normal. The PIC commanded the SIC to follow FD command and re-trim the aircraft as required. The PIC noticed that as soon the SIC stopped trim input, the aircraft was automatically trimming aircraft nose down (AND).

After three automatic AND trim occurrences, the SIC commented that the control column was too heavy to hold back. At 14:25:46 UTC, the PIC declared "PAN PAN" to the Denpasar Approach controller due to instrument failure and requested to maintain runway heading. The Denpasar Approach controller acknowledged the message and approved the pilot request. A few second later, the Denpasar Approach controller asked the LNI043 whether he wanted to return to Denpasar and the pilot responded "standby".

At 14:28:28 UTC, the PIC moved the STAB TRIM switches to CUT OUT. The PIC re-engaged the STAB TRIM switches to NORMAL, but almost immediately the problem re-appeared. The PIC then moved the STAB TRIM switches back to CUT OUT and continued with manual trim without auto-pilot until the end of the flight.

[FredK]

Kyle and Joaquin

I believe that both of you have valid points, and it will be interesting to see how this develops for Boeing in general.

Yes, the 737 is an aging air frame design...engine placement has evolved a long way since those original small engine pods were tucked right under the wings.  So to minimize developmental and pilot training costs Boeing implements an MCAS system to deal with CG balance issues.  Not necessarily a bad thing for sure, but not as eloquent a solution as designing a whole new air frame.  Then, to again minimize pilot training costs Boeing mentions little of MCAS with minimal overall training requirements defined.

So...Has the quest "to minimize costs" breeched a proper safety certification process for these planes?  Where is Boeing on all this with regards to safety?  Where is the FAA oversight on all this with regards to safety?  Where are the airlines on all this with regards to safety.  It seems totally unfathomable to me that in this day and age there would be two catastrophic incidents involved in the process of introducing a new aircraft.  So something is very wrong somewhere.

It seems also unfathomable to me that the airlines do not even have a simulator for training even to this point....almost two years since the first introduction of the MAX. It seems to me that there are enough changes in the MIP layout of things (and with new systems like MCAS) that you would want to educate all that in a simulator environment that challenges you with potential failures.  Can you really learn all that from an IPAD?  I cannot judge that from my own background, but my commercial pilot friends say you can absolutely not.

This raises some issues for Boeing of course....The Airbus 320 NEO employs similarly sized engines but there is more room under the wing to accommodate since the Airbus sits higher off the ground.  I have not heard that there is a similar MCAS system implemented there, but I do not know that for sure.

And what about the Dreamliner?  The wing profile on that plane also sits as similarly low as the 737 and the engines are similarly set on pylons out front.  So clearly Boeing did not think it necessary to raise things off the ground there in a complete new design.  Is there a similar (or identical) MCAS sysytem on the Dreamliner?  Or are there other design features that obviate the need?

It will be interesting to see how all this plays out.  Regarding the MCAS system...it seems that the issue in the Lion Air case is one of bad data inputs rather than with the MCAS system itself.  Perhaps the same for the Ethiopian incident.   Boeing claims to be working on a software fix for MCAS, but that could get pretty convoluted if (1) you absolutely require MCAS operational in certain instances and (2) you absolutely require reliable inputs commensurately.

Fred K

[757Simulator]

Kyle and Joaquin

I believe that both of you have valid points, and it will be interesting to see how this develops for Boeing in general.

Yes, the 737 is an aging air frame design...engine placement has evolved a long way since those original small engine pods were tucked right under the wings.  So to minimize developmental and pilot training costs Boeing implements an MCAS system to deal with CG balance issues.  Not necessarily a bad thing for sure, but not as eloquent a solution as designing a whole new air frame.  Then, to again minimize pilot training costs Boeing mentions little of MCAS with minimal overall training requirements defined.

So...Has the quest "to minimize costs" breeched a proper safety certification process for these planes?  Where is Boeing on all this with regards to safety?  Where is the FAA oversight on all this with regards to safety?  Where are the airlines on all this with regards to safety.  It seems totally unfathomable to me that in this day and age there would be two catastrophic incidents involved in the process of introducing a new aircraft.  So something is very wrong somewhere.

It seems also unfathomable to me that the airlines do not even have a simulator for training even to this point....almost two years since the first introduction of the MAX. It seems to me that there are enough changes in the MIP layout of things (and with new systems like MCAS) that you would want to educate all that in a simulator environment that challenges you with potential failures.  Can you really learn all that from an IPAD?  I cannot judge that from my own background, but my commercial pilot friends say you can absolutely not.

This raises some issues for Boeing of course....The Airbus 320 NEO employs similarly sized engines but there is more room under the wing to accommodate since the Airbus sits higher off the ground.  I have not heard that there is a similar MCAS system implemented there, but I do not know that for sure.

And what about the Dreamliner?  The wing profile on that plane also sits as similarly low as the 737 and the engines are similarly set on pylons out front.  So clearly Boeing did not think it necessary to raise things off the ground there in a complete new design.  Is there a similar (or identical) MCAS sysytem on the Dreamliner?  Or are there other design features that obviate the need?

It will be interesting to see how all this plays out.  Regarding the MCAS system...it seems that the issue in the Lion Air case is one of bad data inputs rather than with the MCAS system itself.  Perhaps the same for the Ethiopian incident.   Boeing claims to be working on a software fix for MCAS, but that could get pretty convoluted if (1) you absolutely require MCAS operational in certain instances and (2) you absolutely require reliable inputs commensurately.

Fred K

Are you a aeronautical engineer? Not being mean. Just curious because your tossing out a lot of unfounded and presumptive speculation.

All the best,

Mike

[blueskydriver]

Here is a nice YouTuber and B737NG Pilot that discusses many topics, including the 737 MAX and it's MCAS. He has also posted about the two recent accidents...

https://www.youtube.com/watch?v=TlinocVHpzk

John

[KyleH]

Fred,

With those other aircraft you mention, they were all designed aerodynamically to operate with the engines they have on them no augmentation system needed. When the NG was created, it got a new wing that again is designed to accommodate the engines that were given to it. This is not the case with the MAX, which resulted in them finding this issue at flight test, requiring the MCAS system.

It is also not a simple matter of training the flight characteristics for the MAX to eliminate the need for MCAS. It is the fact that the regulations do not allow for the control forces to get lighter as you pull back on the yoke. If the MAX doesn't have MCAS - it will not meet certification requirements and not be allowed to fly. The FAA appeared to be satisfied with the solution rather than requiring an aerodynamic fix.

Sim's for the MAX do exist, I've been in one of them. I have no idea if they have the MCAS system simulated. As to weather or not an airline should require a full simulator if they already have an NG one, when the differences in the cockpit are relatively minor I don't know. The engineering side of me says the cost benefit might not be there, an FTD device may be enough. Would be better than videos only.

I'm not saying that there isn't a problem that needs to be dealt with on the MAX, but unlike the DC-10 cargo door, this on the surface looks like an issue that should be able to be safely dealt with by the pilots. Similar to the A330 pitot probe issue that was a contributing factor to the AF447 crash.

I have my suspicions on what the accident sequence for the Lyon Air flight will turn out to be, but will have to wait for the report.

I know for myself that if I was manually flying the aircraft, and those big trim wheels were turning without me commanding it from the switches, I'd be going for the stab trim runaway procedures after checking that the autopilot was indeed off. Now with the stick shaker going off at the same time, it might take longer to notice.

[FredK]

Are you a aeronautical engineer? Not being mean. Just curious because your tossing out a lot of unfounded and presumptive speculation.

All the best,

Mike

For sure....I am not any kind of of trained aeronautical engineer.  I am not even a trained pilot. I certainly do not profess to have a correct understanding of what exactly happened in the two incidents (the official reports of what exactly happened and why have not even been published yet).

That said, I do have a deep interest in aviation and the 737 in particular to the extent that I have invested in a fairly sophisticated 737 cockpit in my home.

That is the extent of any qualifications I have.

The speculative considerations I mentioned are just that.....speculations.....about the debate going as to whether these two incidents are due to design flaw and/or training. From my layman's perspective I simply conclude (speculate) that there were at least serious training deficiencies involved.  I also conclude (speculate) that there was some design or software flaw involved...only because it is really hard for me to fathom that the well experienced pilots on board in both cases could not have successfully handled the situations otherwise.  But yes, those are my opinions.....so challenge away!

I also have curiosities about MCAS and whether such a system exists on other similar aircraft...and if so, why or why not related to design engineering.  But clearly I have raised these as questions, and I also invite comments from those in the know.

Kyle...Thanks you for your insights.

Fred K

[jackpilot]

As usual, once the analysis/reports are available, we all will be in a better position to comment based on documented facts.

[Joe Lavery]

More speculation 

I am a qualified pilot, but only on GA aircraft, the biggest thong I've ever flown is a Norman Islander, (co-pilot only); which to be fair gives me no qualification to speculate on the cause of these two 737 MAX crashes.

However there has recently been a suggestion that there was something wrong with the scew-jack, but again I have not seen this corroborated anywhere.

Yet after the loss of the MD-83 in 2000 through the failure of the Screw-jack, I would have thought that the idea of fail safe would have been the byword for aircraft designers. Not perhaps "this doesn't work properly how can we design around it".

I also have a 737 cockpit, but that doesn't give me any insight at all as to the issue we've all, (very interestingly) been discussing.

[navymustang]

I love the news - they have several times reported screw jack issues as mentioned by Joe. Last night the national news said they found the elevator section and the screw jack was in an unusual position. What the heck does that mean? Shame on the news for reporting such things.

[Joe Lavery]

I have to admit a smile when I read that comment on the news... do you think the crash might have had some hand in the unusual attitude on the screw jack.... maybe!

Incidentally I'm not making light of what was a tragedy for all those who boarded those aircraft, never to see their loved ones again. I cannot imagine the anguish and pain their relatives are feeling right now.

Joe.

[blueskydriver]

Surprised the news media has not said "both aircraft had the MCAS or Makes Crashing Airplanes Simple in use..."! You know how they love a good run on story; especially, now that the weather is getting better...lol! 

John

[757Simulator]

Are you a aeronautical engineer? Not being mean. Just curious because your tossing out a lot of unfounded and presumptive speculation.

All the best,

Mike

For sure....I am not any kind of of trained aeronautical engineer.  I am not even a trained pilot. I certainly do not profess to have a correct understanding of what exactly happened in the two incidents (the official reports of what exactly happened and why have not even been published yet).

That said, I do have a deep interest in aviation and the 737 in particular to the extent that I have invested in a fairly sophisticated 737 cockpit in my home.

That is the extent of any qualifications I have.

The speculative considerations I mentioned are just that.....speculations.....about the debate going as to whether these two incidents are due to design flaw and/or training. From my layman's perspective I simply conclude (speculate) that there were at least serious training deficiencies involved.  I also conclude (speculate) that there was some design or software flaw involved...only because it is really hard for me to fathom that the well experienced pilots on board in both cases could not have successfully handled the situations otherwise.  But yes, those are my opinions.....so challenge away!

I also have curiosities about MCAS and whether such a system exists on other similar aircraft...and if so, why or why not related to design engineering.  But clearly I have raised these as questions, and I also invite comments from those in the know.

Kyle...Thanks you for your insights.

Fred K

Thank you Fred. Great post!

Mike

[jfuenmayor]

Hi guys, I have read with interest all the posts by Kyle Fred and the rest of the crew, and certainly, the points are valid. My simple question is, should software correct for inherent misbehavior of the air frame due the introduction of some modifications that induce said behavior ?.

The Airbus depends heavily on automatic systems and the basic tenet is, if there is enough conflicting information coming from the sensors the autopilot disengages and goes to alternate law since direct law is only possible at or below 250 Kts. and gear down, at least that is what I recall from my 8 hour experience in both the 330 and 320 Level D sims. (lucky me). The similarities between the case of the AF flight and these, other than pilot's inexperience is not applicable. The crew of the AF flight were baffled with a flood of ECAM warnings and what they saw did not make sense to them. The PF at one time  did push the stick forward with no results. I guess in a futile attempt to recover when below 10000 feet they kept the stick back.

There is no doubt that the pressures on the industry is forcing the entry of new pilots with relatively low air time, as low as one hundred and fifty hours. I have trusted information that some airlines send pilots  for type rating only with a Commercial, Instrument and Single Engine experience,  with say, 150 hours of air time, not simulator time. After that, they go to the jump seat and shortly after to the right seat. The reasoning being that the new systems can compensate for the lack of experience. I understand the Captain in the Ethiopian airliner  had 8000 hours and the FO 200 or so.

The problem exists and is very real, two planes have been lost. They just need to get to the bottom of it so the public can regain its confidence . Just for  little a bit of recalling, the Comet's original design flaws,  which led the catastrophic failure of the fuselage after pressurization  were corrected ,but the public never regained their trust in the airplane. The last nail in the coffin was a new kid in town, the 707.

In the case at hand, we do need a heck of a lot more information before drawing any firm conclusions, and true, we are speculating but with some basis. Thinking is not a flaw, but data is king and so, I think that in this instance,  reasonable, reliable information, provided it does not hinder the investigation itself,  has to be made crystal clear to the layman as well as the people in the industry as it is obtained, if we are to regain confidence. A full  report of the probable causes may take over a year, sometime more. Tough situation for Boeing.

Joaquin.

[Joe Lavery]

Well said Sir.... 

Joe.

[tennyson]

To answer the original question by Fred, yes, I am in the process of upgrading to the MAX, from my 737-800NG.

As far as speculation goes about on-going incidents, I will defer my comments, as the major contributors above seem to have a good handle on the guts of it.

I am very concerned at the way we all interpret these events, and I'm not just talking about the Boeing incidents.
The general Media, in it's holier than thou attitudes hangs draws and quarters individuals, businesses and Corporations prior to any hard evidence on mere supposition.

Boeing have taken stock losses in the billions over an incident that may eventually find them completely non-culpable.

I appreciate the level of knowledge and skill that most of us have in the aviation field, but without the true facts and all the facts, all the supposition in the world amounts to nought.

I, in my upgrade path have done and continue to do lots of study on the MAX. I believe that in the following months and years we will see the facts emerge, life will go on and with the eventual enormous savings in fuel and training, the MAX will go on to supersede the 738 and 739's that it was designed for.



Frank 

[jackpilot]

Wise words Frank.

[Trevor Hale]

To answer the original question by Fred, yes, I am in the process of upgrading to the MAX, from my 737-800NG.

As far as speculation goes about on-going incidents, I will defer my comments, as the major contributors above seem to have a good handle on the guts of it.

I am very concerned at the way we all interpret these events, and I'm not just talking about the Boeing incidents.
The general Media, in it's holier than thou attitudes hangs draws and quarters individuals, businesses and Corporations prior to any hard evidence on mere supposition.

Boeing have taken stock losses in the billions over an incident that may eventually find them completely non-culpable.

I appreciate the level of knowledge and skill that most of us have in the aviation field, but without the true facts and all the facts, all the supposition in the world amounts to nought.

I, in my upgrade path have done and continue to do lots of study on the MAX. I believe that in the following months and years we will see the facts emerge, life will go on and with the eventual enormous savings in fuel and training, the MAX will go on to supersede the 738 and 739's that it was designed for.



Frank

I couldn't have said any of the above better myself. Frank.
Thank you!

[FredK]

Keep in mind also that there had been very significant debate within Boeing as to whether to scrap the 737 completely and to develop a wholly new air frame design in its place.  Up to this point the MAX upgrade decision was very clearly the right decision, but only time will tell if that was the right decision longer term.

The bigger challenge perhaps on the horizon for both Boeing and Airbus is China's C919 which is aimed squarely at the MAX/NEO market (under certification now with 800 orders).  Also the CR929 China/Russia joint venture wide body development. Both are planned to utilize engines sourced from GE and/or Rolls to start. The expanding market is China and the rest of the Far East, and rest assured the Chinese airlines will overlook a lot regarding operating cost and quality issues with respect to sourcing from within there own country....that is just how it works there.

Interesting and challenging times ahead for the aviation industry no matter what!

Fred K

[jfuenmayor]

Preliminary report om Ethiopian crash.
Draw your own conclusions.

http://www.ecaa.gov.et/documents/20435/0/Preliminary+Report+B737-800MAX+,(ET-AVJ).pdf