Boeing 737 MAX

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The F.A.A. and Boeing never lead these investigations. In a domestic crash it will be lead by a team of subject-matter experts from the NTSB, a n organization historically more than willing to criticize the F A A and aircraft manufacturers.

The investigator -in-charge has the authority to accredit parties to the investigation, and there will be a dozen or more, standing by to provide expertise. I served as an F A A rep on several of these, though only one involving a Part 121 carrier, CO1713 at Denver, and I can assure you we spoke when asked to. On more than one occasion, "parties" have been discharged for actions seen to compromise The investigation.

The F A A never reads out the F.D.R. nor the C.V.R. the N.T.S.B. does in a very sophisticated lab at L'Enfant Plaza.

The Ethiopian investigation will be "lead" by someone from the E.C.A.A., a notoriously feeble institution, but he will have a lot of assistance to draw on, including Boeing, but almost certainly not the F.A.A.



Thank you for dismissing certain conspiracy theories as nothing more than someone massively miss informed.

This thread has been an incredibly refreshing dose facts and information with minimal opinion and drama. This is how we all learn, where one is so inclined.
 
Yes it is called a stabilator and I believe the above reference to a jackscrew which moves it is misleading. The MD 80 for example works that way. On the 737, the control inputs from the yoke or the autopilot go to the trim tab which basically exerts an aerodynamic force shoving the freely swiveling stabilator where you want it.


Then a small "trim jackscrew" balances the forces so the system achieves a new stable state. This is the bit which was found set "full nose down".

So to be clear, the "stabilator" (aka horizontal stabilizer or elevator, the whole horizontal large surface) on the 737 Max is free floating on its pivot and is only moved by aero forces from the trim tabs? No big jackscrew machine operating the stabilator? Just little jackscrews operating the tabs? This seems counter to what XSbank posted.

I understand the Alaska Airlines crash in the Pacific was caused by a stripped/jammed jackscrew mechanism which controlled the whole stabilator?

So when you pull or push on the yoke it only controls the trim tabs, or does it move the stabilator? If the stabilator is controlled with the jackscrew, then where would the 100lb of force on the yoke come from? Seems there would be no feedback to the yoke if all it did was command the JS motor.

Not sure how relevant this is to the topic, but when trying to pick through a failure I like to have a clear mental image of the machinery.
 
So to be clear, the "stabilator" (aka horizontal stabilizer or elevator, the whole horizontal large surface) on the 737 Max is free floating on its pivot and is only moved by aero forces from the trim tabs? No big jackscrew machine operating the stabilator? Just little jackscrews operating the tabs? This seems counter to what XSbank posted.



I understand the Alaska Airlines crash in the Pacific was caused by a stripped/jammed jackscrew mechanism which controlled the whole stabilator?



So when you pull or push on the yoke it only controls the trim tabs, or does it move the stabilator? If the stabilator is controlled with the jackscrew, then where would the 100lb of force on the yoke come from? Seems there would be no feedback to the yoke if all it did was command the JS motor.



Not sure how relevant this is to the topic, but when trying to pick through a failure I like to have a clear mental image of the machinery.



Hello, longtime lurker and current 737 pilot here.

The 737 does not have a “stabilator” like a piper Cherokee, it has a trim-able tailplane or stabilizer. The aft end of the stabilizer is a hinge and the leading edge is trimmed up and down with a jackscrew.

This jackscrew is motor driven until the flightcrew elects to disconnect it by use of the much discussed switches just aft of the first officers trim wheel, then the jackscrew can be manually turned by the conventional trim wheel.

The 737 still has conventional elevators which are actuated by hydraulic servos which are in turn controlled by a complicated collection of cables, bellcranks, feel generators, etc... Additionally these elevators have “servo” or “balance” tabs on their very trailing edge. These are aerodynamic devices which move in the opposite direction of the elevator to aerodynamically lighten the load of the elevator.

Alaska’s MD80 on flight 261 had a similar system, conventional elevators and a trim-able stabilizer which failed due to a maintenance error, very sad story that one.
 
Thanks, that clears things up.
 
The 737 does not have a “stabilator” like a piper Cherokee, it has a trim-able tailplane or stabilizer. The aft end of the stabilizer is a hinge and the leading edge is trimmed up and down with a jackscrew.
...

...
Alaska’s MD80 on flight 261 had a similar system, conventional elevators and a trim-able stabilizer which failed due to a maintenance error, very sad story that one.


Thanks, I stand corrected.
 
The 737 jackscrew and drive mechanism is about 6' long (give or take). The jackscrew itself is a couple of inches in diameter.

Video showing it working:


Big metal beams in the video is the connection to the stabilizer itself.
 
What`s happening? Must be a lot of parked aircraft not earning $ still requiring lease or other financial resources, and disrupted schedules.
 
What`s happening? Must be a lot of parked aircraft not earning $ still requiring lease or other financial resources, and disrupted schedules.

Boeing is still working on an aircraft change and a training update. It all has to be tested and approved. Boeing has already had a problem with unintended consequences. Probably making *am*** sure it doesn't happen again. The FAA is probably also looking at it very closely too.

AVwebFlash Responsive (Monday)
 
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The 737 jackscrew and drive mechanism is about 6' long

Okay. Here's the enigma: In my years in the F.A.A., in addition to my 2200hours of "little airplane" time, I've got 200 or 300 hours watching the pros fly everything from DHC-7s to Tri-Stars. (wish I'd logged all that learning!).

More than half that time in Boeing 7-somethin' and I can tell you the pitch - trim is impossible to ignore. Not only is there a huge black and white wheel (x2) whirling around a few inches from your thigh, it is NOISY.

There's a lot of talk about the lack of alerting system, but I gotta say that if every time the airplane tries to pitch down that big NOISY wheel spins around, it isn't gonna take long before I shout, "For the love of (insert Diety of choice), shut that frapping thing off!! "

How much alerting is required by an 8000 hour pilot?
 
Okay. Here's the enigma: In my years in the F.A.A., in addition to my 2200hours of "little airplane" time, I've got 200 or 300 hours watching the pros fly everything from DHC-7s to Tri-Stars. (wish I'd logged all that learning!).

More than half that time in Boeing 7-somethin' and I can tell you the pitch - trim is impossible to ignore. Not only is there a huge black and white wheel (x2) whirling around a few inches from your thigh, it is NOISY.

There's a lot of talk about the lack of alerting system, but I gotta say that if every time the airplane tries to pitch down that big NOISY wheel spins around, it isn't gonna take long before I shout, "For the love of (insert Diety of choice), shut that frapping thing off!! "

How much alerting is required by an 8000 hour pilot?

The amount of noise the trim system makes is a function of how old the hardware is. An old one will make a lot of noise when is starts and stops due to wear causing things to loosen up a bit. It'll clank when it starts and clank when it stops (among other noises). On a new airplane, it will make much less noise because things are tight. The white stripes on the wheels are meant to be a visual indicator trim movement. When the flaps are up (MCAS territory) the trim moves a lot slower (and more quietly) than when the flaps are not up.

Planes without the big wheels have artificial warning systems to let you know the trim is in motion (e.g. MD-80s).

The problem is that anyone with more than a few dozen hours in the 737 probably doesn't notice the noise anymore.

Since the MCAS only works in manual flight, a big clue that something is wrong should be the fact that the force on the control column is pulling the thing away from the pilot and when he trims the force off it keeps coming back.
 
Lot of planes sitting on the ground, looking for pilots.

What`s happening? Must be a lot of parked aircraft not earning $ still requiring lease or other financial resources, and disrupted schedules.


My marina pilot neighbour tells me of the repeated calls he gets, requests to fly on a contract basis. Air Canada wants him to fly but at a junior officers bottom rate that is less than his pension. United Emirates has 150 wide0body jets sitting in dry storage unable to crew them. Rates offered 5X Air Canada flight rate. My friend still doesn't want the work; "Tired of taking out the trash!" as he describes the job.
 
Okay. Here's the enigma: In my years in the F.A.A., in addition to my 2200hours of "little airplane" time, I've got 200 or 300 hours watching the pros fly everything from DHC-7s to Tri-Stars. (wish I'd logged all that learning!).

More than half that time in Boeing 7-somethin' and I can tell you the pitch - trim is impossible to ignore. Not only is there a huge black and white wheel (x2) whirling around a few inches from your thigh, it is NOISY.

There's a lot of talk about the lack of alerting system, but I gotta say that if every time the airplane tries to pitch down that big NOISY wheel spins around, it isn't gonna take long before I shout, "For the love of (insert Diety of choice), shut that frapping thing off!! "

How much alerting is required by an 8000 hour pilot?


5000 hours in helicopters and I am so paranoid, a squeek on a bicycle makes me nervous. :)


If ANY machinery is running around me, conversation becomes secondary to noise/vibration.


But that's just me I guess....:D
 
Sounds like Boeing is having a hard time following Air Bust, creating aircraft for 200 hour "pilots".
 
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5000 hours in helicopters and I am so paranoid, a squeek on a bicycle makes me nervous. :)


If ANY machinery is running around me, conversation becomes secondary to noise/vibration.


But that's just me I guess....:D

Paul,

Totally agree, and one wonders how someone can miss the trim wheel. Heck, i used to enjoy turning off the electric trim, pulling out the crank on the trim wheel and trimming by hand. Kinda fun. (there's a retractable crank on the side and one can use it to trim by hand)

BUT, how many pilots have landed gear up, listing to the blaring gear warning horn?
 
If the multiple crash cause is pilot incompetence, Boeing should not mess with computer programs. Airlines should re-educate the pilots who can learn, sack those who can`t, and put the planes back in the air.
 
If the multiple crash cause is pilot incompetence, Boeing should not mess with computer programs. Airlines should re-educate the pilots who can learn, sack those who can`t, and put the planes back in the air.

Bruce,

The Max issue is CLEARLY NOT a pilot issue. Heck, they didn't even know it existed!

Pilots are trained to a minimum standard and if they are competent to that level, good enough. There's a few that have more sense and can figure out stuff beyond the training level, but not to degrade the rest that have met the minimum standard.
 
Bruce,

The Max issue is CLEARLY NOT a pilot issue. Heck, they didn't even know it existed!....
That`s what I thought,but some members professing expertise posting here are intent on tipping the "nightsoil" bucket over the pilots as inexperienced, unobservant, unresponsive, incompetent, and generally negligent. So as a layman, I figured it had to be the man, not the machine.
The other fix, though I don`t see how it works,seems to be rubbishing Airbus. How did they get involved?
Loyalty is admirable,reality is preferable.
 
That`s what I thought,but some members professing expertise posting here are intent on tipping the "nightsoil" bucket over the pilots as inexperienced, unobservant, unresponsive, incompetent, and generally negligent. So as a layman, I figured it had to be the man, not the machine.
The other fix, though I don`t see how it works,seems to be rubbishing Airbus. How did they get involved?
Loyalty is admirable,reality is preferable.

Good points, but when Boeing said they didn't publish the MCAS system in the operating procedures and said, "we don't want to overload the pilot with this info"..... that's clearly leaving the pilots out of the picture.

Sure, there can be "outstanding" pilots that could figure out that there was some unexplained overriding force, and figured out what to do about it, but probably not the norm.
 
"The other fix, though I don`t see how it works,seems to be rubbishing Airbus. How did they get involved?"

Over the years Air Bust has had multiple crashes caused by their flight control system. Air France 447 and ,

2 were at the Paris Air Show , with TEST PILOTS (probably well trained) onboard demonstrating..

"There's a few that have more sense and can figure out stuff beyond the training level, but not to degrade the rest that have met the minimum standard."

The country decides on the standards , 200hour "pilots" may be fine in a 3rd world country , but not in the USA.

Every US pilot gets to play "You Bet Your Job" at least 2x a year.

Time is spent in the box (simulator) doing procedures that are too dangerous to do in a real aircraft.

The training is such that the 3 , or now 2 crew members have usually never met before, and do all the drills to perfection their first time.
 
"The other fix, though I don`t see how it works,seems to be rubbishing Airbus. How did they get involved?"

Over the years Air Bust has had multiple crashes caused by their flight control system. Air France 447 and ,

2 were at the Paris Air Show , with TEST PILOTS (probably well trained) onboard demonstrating..

"There's a few that have more sense and can figure out stuff beyond the training level, but not to degrade the rest that have met the minimum standard."

The country decides on the standards , 200hour "pilots" may be fine in a 3rd world country , but not in the USA.

Every US pilot gets to play "You Bet Your Job" at least 2x a year.

Time is spent in the box (simulator) doing procedures that are too dangerous to do in a real aircraft.

The training is such that the 3 , or now 2 crew members have usually never met before, and do all the drills to perfection their first time.

I'm with ya on this one. I was never a fan of the Airbus..... and didn't want to be a bus driver. They were really designed for 3rd world countries, and WAY too much automation.

Yes, there were a lot of 200hr pilot wonders that got hired into major US carriers, but most were put in the Flight Engineers seat. Today, one needs 1500 hours to get in, and that's overkill too as carriers are parking plane for lack of crew. It's always been feast or famine in the airline business.
 
Unfortunately as aircraft become more and more technologically sophisticated, the more automated systems are needed. Without the computer, a pilot cannot fly a B1 because the required inputs to keep a flying wing airborne are beyond human capability. IMO, Airbus went way too far in that direction, and Boeing is still trying to keep ultimate safety of the aircraft squarely in the pilot's chair.
 
Read up on the Sioux City DC10 crash...some pilots don't need flight controls at all to "almost" successfully land. :)
 
"The other fix, though I don`t see how it works,seems to be rubbishing Airbus. How did they get involved?"

Over the years Air Bust has had multiple crashes caused by their flight control system. Air France 447 and ,

2 were at the Paris Air Show , with TEST PILOTS (probably well trained) onboard demonstrating..

"There's a few that have more sense and can figure out stuff beyond the training level, but not to degrade the rest that have met the minimum standard."

The country decides on the standards , 200hour "pilots" may be fine in a 3rd world country , but not in the USA.

Every US pilot gets to play "You Bet Your Job" at least 2x a year.

Time is spent in the box (simulator) doing procedures that are too dangerous to do in a real aircraft.

The training is such that the 3 , or now 2 crew members have usually never met before, and do all the drills to perfection their first time.
Much as I expected FF. Zero to do with the Max737. Just a gratuitous attack on another manufacturer to divert heat off Boeing while their defective aircraft sit in rows,banned from the sky,except for relocation without pax,though even that has resulted in an emergency landing.
 
Much as I expected FF. Zero to do with the Max737. Just a gratuitous attack on another manufacturer to divert heat off Boeing while their defective aircraft sit in rows,banned from the sky,except for relocation without pax,though even that has resulted in an emergency landing.

Not so much a "gratuitous attack" as an observation that Airbus has had a few crashes due to pilots being unable to wrest control of the aircraft from a malfunctioning computer. With the Boeing plane, wresting control of the aircraft for this issue seems to involve two fingers worth of effort. Be that as it may, the recent emergency landing was due to an engine issue, which does happen. Kind of like this: https://www.cnn.com/2017/10/01/americas/air-france-66-a380-engine-failure/index.html, or this https://en.wikipedia.org/wiki/Air_Transat_Flight_236, or this https://en.wikipedia.org/wiki/Qantas_Flight_32, or, well you get the picture.

And to characterize the Boeing plane as "defective" would seem to involve a lot of presumption on your part. Do you have insight into the NTSB's work we should know about? This may, or may not, turn out to be a case where software has to be modified to accommodate pilot error or lack of training, or it may be some other much more serious problem. The point of grounding the fleet is not because anyone can make that determination quite yet, but to find out what needs to happen to prevent its reoccurrence.
 
I'm with ya on this one. I was never a fan of the Airbus..... and didn't want to be a bus driver. They were really designed for 3rd world countries, and WAY too much automation.

Yes, there were a lot of 200hr pilot wonders that got hired into major US carriers, but most were put in the Flight Engineers seat. Today, one needs 1500 hours to get in, and that's overkill too as carriers are parking plane for lack of crew. It's always been feast or famine in the airline business.

I think that's very perceptive, Seevee. Boeing did want to rush this modified 737 form into production to meet competitive challenges from Airbus and sell to markets where pilots may not be quite as well trained as they might be, and automation in theory reduces the need for pilot expertise.

I wonder if the fact that both Ethiopian Airways and Lion Air have mixed fleets of Airbus and Boeing had any effect on pilot training? A pilot used to flying a computer friendly Airbus is going to have a very different experience than one trained to fly the pilot friendly Boeing planes.

Curious about the fleets of these airlines, I came across this on the Lion Air website:

"This mighty aircraft can fly about 500 miles above the sea, up to 3,200 nm (5,925km) to the AUX tank. "

Could be that is their problem. Flying at an altitude of 2.64 million feet might be bit dicey....:whistling:
 
OOKKK
I just found this thread and honestly, it's one of of the few ever that I've ever trad from beginning to end that is multiple pages long.

I liked it because there were a lot of good questions and answers.
While not a pilot, I've been interested in and involved in aviation for more than 40+ years and have probably read every accident report that I ever knew about.
In 1981, I was a member of an Air Force accident investigation board that convened for 30 days a Luke AFB.
I was fascinated with the process and how our diagnosis evolved over those 30 days, first from input of the NSTB, then from two Boeing engineers, who were able to finally put all the pieces of the puzzle together.

I think in the this whole 737 MAX issue there are a number of issues, factors which help to obscure the issue.

The first is that there are many assumptions that are either not mentioned or ignored because they are "obvious", but in this case may not be.

The second is that it seems to me that there are many, even in aviation journalism, who don't really seem to understand the issues they are talking about coupled with some pilots who while they may understand the differences in the Max vs the NG, don't to enough to articulate those differences.

I'm a Boeing-phile, since I first arrived in Seattle in the fall of 1969 and saw all those 747's lined up on Boeing Field. Airbus' rush to automation and reduction of pilot influence has only strengthened by pro Boeing sense.

But no matter how one looks at it, Boeing made a computer program to make the MAX fly like the NG and then didn't really tell anyone about it.

And yes, American pilots and certification is certainly better than any place else, even Western Europe in my mind, but still.

American and Southwest who are the main USA users opted for the "warning option of AOA failure".
Oops, how was third world country supposed to know they needed that?

Seevee, made a real interesting quote:

"- One of the things mentioned is that the aircraft was traveling at high speed at the end. With the trim full nose down (according to the jackscrew) the crew may not have the physical strength to pull the nose up or to hold it up for any length of time (even with both pilots pulling with both feet on the panel).

- The emergency checklist has a drill for trim runway. However, the first thing on the page is that the drill applies if the trim is "Uncommanded stabilizer trim movement occurs continuously." The MCAS does not operate the trim continuously, it does it intermittently. This is a subtle difference, but might cause less experienced pilots to think that this drill is not applicable to operation of the trim due to a MCAS fault. The pilots should be trained to use the runway trim drill any time the trim is not working as they expect."

So two things stand out for me. Here we see for the first time, that the pilot could not physically overpower the controls of a Boeing plane, as I would think many pilots thought they could?
Second, that little word, "continuously", is not a minor issue. Even if you had been flying a plane for a long time. AS I UNDERSTAND IT, that once the pilot used the column mounted trim switch to counteract the MCAS trim down, the pilot adjusts the trim and everything is great for 9 (or 5?) seconds. So it's not runaway trim, which every pilot is trained to deal with.
what's happening now is trim goes 2.5 degrees nose down, pilot manually changes using yoke mounted trim, everything is OK, until 9 second later, then trim does not go another 2.5 degrees but instead, (if I understand correctly, goes from the PREVIOUS reading, ANOTHER 2.5 degrees).
Thus they get into a pattern in which the plane is being pitched down in an increasing rate.
Not the easiest pattern to understand.

Lastly, this generation is not us.
Many of you know that besides being an Meteorologist, I'm also an educator.

I learned to calculate using a slide rule. To use a slide ruler correctly, one must understand magnitudes, as well as significant digits.

Thus to multiply 101x11, I had to know that the answer should be near 1,000 and the last digit should be a 1.
Today, kids are given, using calculators, which will tell them the correct answer, 1,111.
But the problem is many don't understand magnitudes or even when the answer makes no sense, thus on many tests, a simple question like the above results in ridiculous answers because they put the wrong numbers in the calculator or used the wrong factor thus resulting in an answer of 112,211.

New York State has good science and math standards, so these kinds of concept, magnitude tests were done all the time.

My point is our generation learned to fly, drive, etc in a non computer world, so we understand the concepts and can then apply them to the modern world using computers, calculators, etc.
The current generation missed that first step.

Boeing obviously felt, rightly or wrongly, that accidents would be minimized with less pilot awareness.
Sadly they are probably right.
 
737 MAX - MCAS

This links to an in depth explanation of MCAS. Sorry if it's a repost.

This is the first time I caught the AoA disagree alert - will now be standard on all MAX aircraft.

aoa-display-max.jpg
 
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"This mighty aircraft can fly about 500 miles above the sea, up to 3,200 nm (5,925km) to the AUX tank. "

Could be that is their problem. Flying at an altitude of 2.64 million feet might be bit dicey....:whistling:[/QUOTE]https:


If it was good enough for Jules Verne........... :rolleyes:

//www.youtube.com/watch?v=eSiuDXTMj_A
 
"Not so much a "gratuitous attack" as an observation that Airbus has had a few crashes due to pilots being unable to wrest control of the aircraft from a malfunctioning computer."

Not so,at the Paris air show crashes the Air Bust computer was doing just what it was programmed to do, no malfunction.

The problem was the computer overrode what the pilots wanted to do,, show off the aircraft to the crowds.

Built for marginal skilled seat warmers, the computer program would have been fine at normal flight operation, but skilled pilots showing off was not part of the installed program .
 
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