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Old Jan 4, 2021, 1:37 am
FlyerTalk Forums Expert How-Tos and Guides
Last edit by: WineCountryUA
This is an archive thread, the archive thread is https://www.flyertalk.com/forum/united-airlines-mileageplus/1960195-b737max-cleared-faa-resume-passenger-flights-when-will-ua-max-flights-resume.html

Thread Topic
The reason for continuing this thread is to inform the UA traveler on the status of the MAX recertification and if / when UA might deploy the MAX aircraft. And UA flyer's thoughts about UA deploying the MAX if that was to happen.

Originally Posted by WineCountryUA
READ BEFORE POSTING

Once again many posters in this thread have forgotten the FT rules and resorted to "Personal attacks, insults, baiting and flaming " and other non-collegial, non-civil discourse. This is not allowed.

Posters appear to be talking at others, talking about others, not discussing the core issues. Repeating the same statements, saying the same thing LOUDER is not civil discourse. These problems are not with one poster, they are not just one point of view, ...

As useful as some discussion here has been, continuing rules violations will lead to suspensions and thread closure. Please think about that before posting.

The purpose of FT is to be an informative forum that, in this case, enables the UA flyer to enhance their travel experience. There are other forums for different types of discussions. This thread was had wide latitude but that latitude is being abused.

Bottom line, if you can not stay within the FT rules and the forum's topic areas, please do not post.
And before posting, ask if you are bringing new contributing information to the discussion -- not just repeating previous points, then please do not post.

WineCountryUA
UA coModerator
Originally Posted by WineCountryUA
This thread has engendered some strongly felt opinions and a great tendency to wander into many peripherally related topics. By all normal FT moderation standards, this thread would have been permanently closed long ago ( and numerous members receiving disciplinary actions).

However, given the importance of the subject, the UA Moderators have tried to host this discussion but odd here as UA is not the top 1 or 2 or 3 for MAX among North America carriers. However, some have allowed their passion and non-UA related opinions to repeatedly disrupt this discussion.

The reason for continuing this thread is to inform the UA traveler on the status of the MAX recertification and if / when UA might deploy the MAX aircraft. And UA flyer's thoughts about UA deploying the MAX if that was to happen.

Discussion of Boeing's culture or the impact on Boeing's future is not in scope. Nor is comments on restructuring the regulatory process. Neither is the impacts on COVID on the general air industry -- those are not UA specific and are better discussed elsewhere. And for discussion of UA's future, there is a separate thread.

Additionally repeated postings of essentially the same content should not happen nor unnecessarily inflammatory posts. And of course, the rest of FT posting rules apply including discuss the issue and not the posters.

The Moderator team feels there is a reason / need for this thread but it has been exhausting to have to repeated re-focus the discussion -- don't be the reason this thread is permanently closed ( and get yourself in disciplinary problems).

Stick to the relevant topic which is (repeating myself)
The reason for continuing this thread is to inform the UA traveler on the status of the MAX recertification and if / when UA might deploy the MAX aircraft. And UA flyer's thoughts about UA deploying the MAX if that was to happen.

WineCountryUA
UA coModerator



United does not fly the 737 MAX 8 that has been involved in two recent crashes, but it does operate the 737 MAX 9.

How to tell if your flight is scheduled to be operated by the MAX 9:

View your reservation or flight status page, either on the web or on the app. United lists the entire aircraft type. Every flight that is scheduled to be on the 737 MAX will say "Boeing 737 MAX 9." If you see anything else -- for example, "Boeing 737-900," it is not scheduled to be a MAX at this time.

The same is true in search results and anywhere else on the United site.

For advanced users: UA uses the three letter IATA identifier 7M9 for the 737 MAX 9.

All 737 MAX aircraft worldwide (MAX 8, MAX 9, and MAX 10) are currently grounded.




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Old Mar 21, 2019, 5:29 am
  #646  
 
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For those that keep insisting on pilot error or pilots not knowing their procedures, you need to look this in context:

- In the previous flight, the one that experienced the same problems and got saved, this is what was written in the electronic reporting system:

Airspeed unreliable and ALT disagree shown after takeoff, STS also running to the wrong direction, suspected because of speed difference, identified that CAPT instrument was unreliable and handover control to FO. Continue NNC of Airspeed Unreliable and ALT disagree. Decide to continue flying to CGK at FL280, landed safely runway 25L.
No mention of trim besides the "STS running to the wrong direction" that was probably MCAS doing its thing. Also no mention of the trim cutout procedure that was used.

- In the fateful flight the crew was aware of airspeed and alt issues in the previous flight and when those issues started to appear they naturally focused on them - like the latest CVR reports that came out yesterday say. So not only they were not aware of MCAS and how it worked, they were also influenced by the previous flight report (also unaware of MCAS).

- Regarding trim, and that it is a "simple procedure" to shut it down, here's a 737 captain opinion on it (from PPrune):

As a long-time 737 driver I'll just chime-in a few points.

My First Point: If we don't catch this mis-trim early, un-doing it manually will take a very long time and maybe more time than is available when your aircraft is only 1000' AGL. AND to use the trim wheel for more than small changes, one has to fold the handle out. A handle that has injured many a knee in simulator sessions because combined with the trim motor's speedy rotation of the wheel, it can leave one with a permanent limp.

Second: For all the arm-chair Monday morning QB's who are saying: "Oh, they should have recognized it immediately and disconnected the trim:"

(1) Just after takeoff there is a lot going on with trim, power, configuration changes, and as noted above, the darn speed trim is always moving that trim wheel in seemingly random directions to the point that experienced NG pilots would treat its movement as background noise and normal ops. Movement of the trim wheel in awkward amounts and directions would not immediately trigger a memory item response of disconnecting the servos. No way.

(2) The pilots could very reasonably not have noticed the stab trim movement. Movement of the stab trim on the 737 is indicated by very loud clacking as the wheel rotates. On the -200 it was almost shockingly loud. On the NG, much less so. HOWEVER, the 737 cockpit is NOISY. It's one reason I am happy to not be flying it any more. The ergonomics are ridiculous. Especially at high speeds at low altitudes. With the wind noise, they may not have heard the trim wheel moving. The only other way to know it was moving would be yoke feel and to actually look at the trim setting on the center pedestal, which requires looking down and away from the windows and the instruments in a 'leans'-inducing head move. On the 717, for example, Ms. Douglas chimes in with an audible "Stablizer Motion" warning. There is no such indication on the 737.

(3) The fact that they were at high power and high speed tells me the stick shaker was activated. With that massive vibrator between your legs, alternating blue sky and brown out the window, your eye balls bouncing up and down in their sockets as the plane lurches up and down in positive and negative G's, it would have been a miracle if one of the pilots calmly reached down, flicked off the stab servo cutout switches, folded out the trim handle, and started grinding the wheel in the direction of normalcy. These pilots said over the radio that they had "unreliable airspeed". So they did not even know which instruments to rest their eyes on for reliable info. Their eyes were all over the cockpit looking for reliable info, the plane is all over the place like a wild boar in a blanket not behaving in any rational way. And the flying pilot may have been using the tiny standby IFDS for airspeed and attitude. Ouch.

Finally, runaway stab trim is a very, very rare occurence up until now. We trained it about once every other year in the sim because it is so rare. And when we did it was obvious. The nose was getting steadily heavier or steadily lighter with continuous movement of the trim wheel. That is a VERY different scenario than what these pilots faced.

We also trained for jammed stabilizer, the remedy for which is overcoming it with force. The information they were faced with could very reasonably have been interpreted that way, too.

An URGENT AD from the FAA/ Boeing after Lion Air would have helped get it back to the front of the pilot's minds for sure. Extra training by the airline or an urgent pilot memo would have helped. Maybe one was issued, we don't know yet.

A better question might be: given this nose down attitude, high speed, and fully nose down or almost fully nose down stab, how much altitude would they have had to have to be able to recover. I'm thinking at least 10000 feet to recognize the problem, disconnect the switches, fold out the handle and start frantically winding the stab back to normalcy while the flying pilot tries to gain control via the elevator. It's entirely possible that this scenario, if not recognized early on, is unrecoverable at any altitude.
- Continuing on the trim issue, put yourselves in the LionAir's flight crew position: the plane is acting up (like described in the quote above) plus triming nose down. By logic you know it is not runaway trim because not only the trim stops after a few seconds (therefore not running ungoverned or continuous - this also does not fit the QRH runaway trim procedure so you complete the checklist before turning it off!) but also you can still use the electric trim in your yoke! (how can it be trim runaway if I can still move it? Puzzling and confusing.) So in the end they are flying an aircraft that is constantly pitching down and they have no idea why. And the only way to counter it is... using the electric trim. Now I ask: how was this crew expected to turn off the trim completely when, in their view, it was the only thing keeping them flying? Hindsight is a beautiful thing...

Food for thought.
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Old Mar 21, 2019, 6:36 am
  #647  
 
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Originally Posted by justatourist
For those that keep insisting on pilot error or pilots not knowing their procedures, you need to look this in context:

- In the previous flight, the one that experienced the same problems and got saved, this is what was written in the electronic reporting system:

No mention of trim besides the "STS running to the wrong direction" that was probably MCAS doing its thing. Also no mention of the trim cutout procedure that was used.
.
This is a very good post and I'm not going to quote the entire thing for purposes of brevity, but note the STS is the speed trim system, which functions much like the MCAS, and a failure/incorrect activation thereof will present in a similar way and is remedied the same way. One difference is the STS is designed with better fail-safe architecture than MCAS, for reasons that are unclear.

Any flight control anomaly during a high-workload and altitude-critical situation can be disastrous, so the argument is a reasonable one and supports the theory that:

1) the flight crew in both cases did not respond properly to a unscheduled trim event, which can be attributable to a panoply of factors including workload, phase of flight, lack of altitude, training, experience, awareness of the problem, familiarity with non-normal procedures, etc.; and
2) a system designed by Boeing appears to be insufficiently redundant, with a failure mode that very quickly escalates to a near-catastrophic level with a single faulty input. Whether this is an unintended consequence of the design or a miscalculation in a failure analysis, it still represents an unacceptable risk.

I hope I'm not coming across as though I only view the pilots to blame here, and that the aircraft is generally safe. I unequivocally do not. However, the nature of this disaster and its investigation is highly technical, while it attracts worldwide attention, which causes a lot of misinformation to flow through the public consciousness. At this point, it's still too early to point the finger at one actor.
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Old Mar 21, 2019, 7:03 am
  #648  
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Originally Posted by LarryJ
Every airplane that has a powered pitch-trim system has a runaway trim (or stabilizer) procedure. That includes every airliner build since the beginning of the jet age. I have learned and practiced the runaway trim/stabilizer procedure in every transport jet, and a few general aviation airplanes, that I've flown including the CRJ, DC8, DC9, B757, B767, and B737. This isn't something obscure that is hidden in the fine print of a thousand-page manual.
But did it really present as runaway trim? Runaway trim presents itself as a constant, continuous increase or decrease in trim. Here it was intermittent. Sure at some point they may have figured out that cutting out the trim was the correct response, but I can see how it might not have been the first thing they thought about, and they didn't have the luxury of altitude to think about everything.

Of course now we have the benefit of 20/20 hindsight to see that the runaway trim procedure would have been the correct response, but I am not sure it is fair to say (at least for the Lion Air pilots) that they should have realized that right away.
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Old Mar 21, 2019, 7:29 am
  #649  
 
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The NYT is reporting that United did not take up the optional features Boeing offers that can help avoid the situation that Lion Air and (possibly) Ethiopian faced. Saying pilots use "other data" is not an inspiring response, but perhaps some of the experts here can chime in?

Faulty data from sensors on the Lion Air plane may have caused the system, known as MCAS, to malfunction, authorities investigating that crash suspect.

That software system takes readings from two vanelike devices called angle of attack sensors that determine how much the plane’s nose is pointing up or down relative to oncoming air. When MCAS detects that the plane is pointing up at a dangerous angle, it can automatically push down the nose of the plane in an effort to prevent the plane from stalling.

One of the optional upgrades, the angle of attack indicator, displays the readings of the two sensors. The other, called a disagree light, is activated if those sensors are at odds with one another.

Boeing will soon update the MCAS software, and will also make the disagree light standard on all new 737 Max planes, according to a person familiar with the changes, who spoke on condition of anonymity because they have not been made public. The angle of attack indicator will remain an option that airlines can buy.
United Airlines, which ordered 137 of the planes and has received 14, did not select the indicators or the disagree light. A United spokesman said the airline does not include the features because its pilots use other data to fly the plane.

Last edited by LouieBOS; Mar 21, 2019 at 7:46 am Reason: Article link
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Old Mar 21, 2019, 7:39 am
  #650  
 
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Originally Posted by lem144
The NYT is reporting that United did not take up the optional features Boeing offers that can help avoid the situation that Lion Air and (possibly) Ethiopian faced. Saying pilots use "other data" is not an inspiring response, but perhaps some of the experts here can chime in?
More disturbing news seems to keep coming regarding the MAX program. Selling safety features only as optional extras seems a suspect business mode, and disconcerting to learn that for example Japan requires safety features that the FAA does not.
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Old Mar 21, 2019, 7:41 am
  #651  
 
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According to the same article, UA is the only US carrier that opted not to outfit its Maxes with at least one of the AOA alert features (AA has both). I wonder what "other data" UA pilots may be relying on that AA and SWA are not.
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Old Mar 21, 2019, 7:55 am
  #652  
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Originally Posted by Michael899
According to the same article, UA is the only US carrier that opted not to outfit its Maxes with at least one of the AOA alert features (AA has both). I wonder what "other data" UA pilots may be relying on that AA and SWA are not.
I'd guess airspeed and attitude, but that's just guessing.
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Old Mar 21, 2019, 8:11 am
  #653  
 
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Originally Posted by Bear96
But did it really present as runaway trim? Runaway trim presents itself as a constant, continuous increase or decrease in trim. Here it was intermittent. Sure at some point they may have figured out that cutting out the trim was the correct response, but I can see how it might not have been the first thing they thought about, and they didn't have the luxury of altitude to think about everything.

Of course now we have the benefit of 20/20 hindsight to see that the runaway trim procedure would have been the correct response, but I am not sure it is fair to say (at least for the Lion Air pilots) that they should have realized that right away.
It's probably more appropriate to call it unscheduled trim rather than "runaway". The presentation is pitch trim inputs counter to those commanded, or inputs when no manual action is made. This would only be when hand flying, so the PF should (arguably) be aware of the airplane doing something s/he isn't telling it to do, e.g. increasing back pressure on the yoke despite continuous nose-up electric trim commands.

Originally Posted by lem144
The NYT is reporting that United did not take up the optional features Boeing offers that can help avoid the situation that Lion Air and (possibly) Ethiopian faced. Saying pilots use "other data" is not an inspiring response, but perhaps some of the experts here can chime in?
UA, as a matter of procedure, does low-visibility/CAT III approaches in the 737 (all series, including NG) via autoland rather than manually-flown with visual guidance with HUD like AA, DL, WN, a phase of flight where such information is arguably most important.

This would be another one of those times where jumping to conclusions about overall safety based on disparate data points would not be advisable.

Last edited by EWR764; Mar 21, 2019 at 8:21 am
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Old Mar 21, 2019, 8:18 am
  #654  
 
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Originally Posted by Braniff
Selling safety features only as optional extras seems a suspect business mode...
That's something that is not unique to the 737Max, Boeing or to the aviation industry.

Many safety features in personal vehicles are options as well. I doubt many people demand every safety feature.
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Old Mar 21, 2019, 8:34 am
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Originally Posted by Newman55
That's something that is not unique to the 737Max, Boeing or to the aviation industry.

Many safety features in personal vehicles are options as well. I doubt many people demand every safety feature.
"Both siderism" much?

Comparing choices on a personal vehicle to an airplane
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Old Mar 21, 2019, 8:42 am
  #656  
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Originally Posted by EWR764
It's probably more appropriate to call it unscheduled trim rather than "runaway".
Right. That is why I think it might be unfair to expect a pilot who thinks he may be experiencing unscheduled trim to immediately know to execute the runaway trim procedure.

Eventually he may decide to try that after nothing else is working (and here there was very little time to troubleshoot), but I would think there might be a bit of hesitation about the procedure not being the right one, or even making the situation worse, since it really isn't the procedure for what he appeared to be experiencing.
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Old Mar 21, 2019, 8:46 am
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Originally Posted by malgudi
"Both siderism" much?

Comparing choices on a personal vehicle to an airplane
How about this?

Airbus also has options for additional safety features. You think every airline in the world gets every safety feature available?
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Old Mar 21, 2019, 8:53 am
  #658  
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Originally Posted by justatourist
For those that keep insisting on pilot error or pilots not knowing their procedures, you need to look this in context:

- In the previous flight, the one that experienced the same problems and got saved, this is what was written in the electronic reporting system:



No mention of trim besides the "STS running to the wrong direction" that was probably MCAS doing its thing. Also no mention of the trim cutout procedure that was used.

- In the fateful flight the crew was aware of airspeed and alt issues in the previous flight and when those issues started to appear they naturally focused on them - like the latest CVR reports that came out yesterday say. So not only they were not aware of MCAS and how it worked, they were also influenced by the previous flight report (also unaware of MCAS).

- Regarding trim, and that it is a "simple procedure" to shut it down, here's a 737 captain opinion on it (from PPrune):



- Continuing on the trim issue, put yourselves in the LionAir's flight crew position: the plane is acting up (like described in the quote above) plus triming nose down. By logic you know it is not runaway trim because not only the trim stops after a few seconds (therefore not running ungoverned or continuous - this also does not fit the QRH runaway trim procedure so you complete the checklist before turning it off!) but also you can still use the electric trim in your yoke! (how can it be trim runaway if I can still move it? Puzzling and confusing.) So in the end they are flying an aircraft that is constantly pitching down and they have no idea why. And the only way to counter it is... using the electric trim. Now I ask: how was this crew expected to turn off the trim completely when, in their view, it was the only thing keeping them flying? Hindsight is a beautiful thing...

Food for thought.
I could imagine the pilot in charge in the first Lion Air incident--the one that managed to land safely--not being eager to disclose to his/her employer that the aircraft was saved by the actions of the third person in the cockpit, namely the trained pilot who was off duty and riding in the jumpseat. It doesn't surprise me that the reports on the incident therefore downplay exactly what happened and how it was remedied.

In fact, the way the third pilot up front was able to diagnose the problem and knew how to correct it further indicates to me the need for multiple well trained pilots to fly the MAX, in contrast to the Ethiopian Air copilot with only 200 hours. Effectively that flight had only one pilot and it would have been worse if the copilot had panicked or gotten in the way of the more experienced pilot doing what was needed.
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Old Mar 21, 2019, 8:55 am
  #659  
 
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Originally Posted by Bear96
Eventually he may decide to try that after nothing else is working (and here there was very little time to troubleshoot), but I would think there might be a bit of hesitation about the procedure not being the right one, or even making the situation worse, since it really isn't the procedure for what he appeared to be experiencing.
Certainly within the realm of possibility, and my argument is they should never have been in that situation, that quickly, in the first place. But failing to diagnose and correct a problem for which a relatively simple, intuitive remedy exists because "it's rare" isn't a great excuse when the alternative is a smoldering hole in the ground. Even if it's an unusual condition, there are cues available to suggest corrective measures.
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Old Mar 21, 2019, 10:09 am
  #660  
 
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If the crew was focused on solving the problem that they were previously made aware of, did they fail with CRM (Crew Resource Management) by just being fixated on faulty readings? Additionally, not having enough airspace to work with, only complicated matters. They were fixated on not-crashing. Could they have reached out to their ops teams and asked for help? Or have the ops team reach out to the last crew? We will never know what could have gone through their mind before the crash.

Last edited by IADFlyer123; Mar 21, 2019 at 10:22 am
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