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MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures

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MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures

Old 3rd Jun 2019, 00:09
  #141 (permalink)  
 
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Originally Posted by GordonR_Cape View Post
The following story popped up in my news feed: https://www.reuters.com/article/us-b...-idUSKCN1T30RX
Something wrong with the numbers 300 planes affected by 148 parts?
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Old 3rd Jun 2019, 02:29
  #142 (permalink)  
 
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Originally Posted by FrequentSLF View Post
Something wrong with the numbers 300 planes affected by 148 parts?
Might not know which plane they are on till you check them individually.
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Old 3rd Jun 2019, 04:35
  #143 (permalink)  
 
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Originally Posted by GordonR_Cape View Post
The following story popped up in my news feed: https://www.reuters.com/article/us-boeing-faa-airplane/some-boeing-737-max-planes-may-have-faulty-parts-faa-idUSKCN1T30RX
The FAA said up to 148 leading edge slat tracks manufactured by a Boeing sub-tier supplier are affected and cover 133 NG and 179 MAX aircraft worldwide.
The defective parts which had affected 179 Max'es?? That's more than half of the Max'es in operation. Another question: the defective parts had not been installed in either PK-LQP or ET-AVJ, had they? I don't like the odd. The chance of any random Max'es got affected by the defect is bigger than 50:50.
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Old 3rd Jun 2019, 06:20
  #144 (permalink)  
 
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Originally Posted by ProPax View Post
Oh, joy! How long does it take the MTX to replace the slats, per aircraft?
The slats are OK. It is some tracks which will need replacement. 2 day down time was quoted on CNN news - presumably after delivery of heat treated parts.
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Old 3rd Jun 2019, 06:54
  #145 (permalink)  
 
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Originally Posted by Bend alot View Post
The issue that the simulator trim wheel forces are lower than in the actual aircraft - so it is not a simulation, and we/most do not know at what stage the manual trim wheel will not be able to be moved ( near full forward or not far past natural, in seconds of a runaway trim). Given the manual trim wheel is hardly used in normal flight, most pilots I expect would be very surprised in the force required to move a moderate out of trim stabiliser. That comment based on known history and recent reductions in trim wheel size - they certainly did not make "it" easier to move!

This was a recent discovery, so your training may not be relevant in a real case of survival incident - but you would pass with flying colours in the simulator.
No training, we just tried out various stab settings and speeds vs manual trim.
I imagine manual trim can be impossible at nearly any stab settings. It’s all about the load on the stab.
This is a 737 issue since none of the other aircraft I have flown have had a manual trim wheel like the 737.
Had Boeing removed the trim wheel on the Max and made it electric only, we would not have this discussion.
I have no worries about the NG. I have never had a runaway trim. I have never had an AOA fail.

*Knock on wood*
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Old 3rd Jun 2019, 07:41
  #146 (permalink)  
 
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Originally Posted by gums View Post
Salute!
Thanks Bend and PEI.
I just have a hard time with Boeing not keeping the manual electric trim operating when MCAS does its trick.

Looks like Boeing is sticking to the "existing procedures would have prevented the crashes" story. Ditto for some of the uber pilots here. Problem is recognizing what is wrong and the magnitude/length of the MCAS commands.

PEI might be able to explain it in technical terms that some here will not fathom, but I say go for it.
- Why can't the trim commands be a function that uses "q" and mach as we did in the Viper instead of a "bang-bang" fixed amount and fixed time of application? In other words, follow a geometric plot as we did for AoA versus gee and control deflection gains.
- If MCAS is using the A/P circuits, why disable other force functions such as the control column switches for force ( not the electric switches).

Gotta be nore than meets the eye, and I do not feel training is the answer. Fer chrissakes, we are not training Top Gun fighter pilots or NASA astronauts.

Gums sends...
Hi there Gums. Always enjoy your posts which throw up interesting points
Think this is the core of the problem. My view is that the pilots I grew up with were the top guns of the civil world. They needed to be. B747 quadruple engine failure. b744 turned upside down by intruder and lost 2 miles altitude in 90 seconds. Sioux City. Hudson River + a thousand more. All flown to the a safe landing, or least worst outcome as per Sioux City.

So, Boeing fix MCAS and make sure you can trim STAB in all realistic scenarios. Done already I would imagine. Software + hardware fixes. Awaiting the politicians and spin doctors on both sides - ah! And lawyers, to release plane for service.
So alls we’ll then. Back to “normal”. Well no. Because we’ve been going down a path for some years of downgrading pilot training to the point where the only time they are really needed- when automatics fail badly, they can’t cope.
A daily example and exception is xwind landings which currently automatics can’t do > 25 kts wet. Max wind 30:kts.
But they practice it so often that’s ok.
But given an ET style multiple failure scenario, or QF Ex SIN they have nothing to fall back on. And unless our engineer friends can produce a crash proof plane, dream on, this is going to get worse.
so the nightmare facing the industry and regulators is not MCAS or STAB issues. It’s the thousands of pilots already out there like this, and the 30,000 needed over next few decades.
My view? Bite the bullet and train them. But, the core of the problem is there aren’t enough of them with the “right stuff” to be trained. Start up airlines popping up and just buying “”:buses with wings” and some xbox guys to fly them.
In my airline (one of...) it took 10-15 years 10,000 hours to be put in command. And boy were you glad when the unexpected was thrown at you.
But I hear some say”get that dinosaur off this forum before my brain explodes with anger and indignation! “
Isn’t there a forum for old farts that he could join? Where he can dream of halcyon days when pilots could fly a plane with stick and rudder and a thing called airmanship? And think outside the box and understand the systems enough to know right from wrong?
I will tootle off now and take my blood pressure pills.
Y
Im looking for one,
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Old 3rd Jun 2019, 08:12
  #147 (permalink)  
 
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yanrair,
My view? Bite the bullet and train them. But, the core of the problem is there aren’t enough of them with the “right stuff” to be trained.”
You appear to exclude yourself - ‘train them’, but no training for you. Retired ? But you still need to train your mind.
When would the industry reach the required standard, who would judge, how.

alf, … just ‘an old f…’, but prepared to consider alternative views, consider what the industry’s current safety needs are, and how they could be met - practical, cost effective.
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Old 3rd Jun 2019, 09:40
  #148 (permalink)  
 
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Originally Posted by yanrair View Post

Hi there Gums. Always enjoy your posts which throw up interesting points
Think this is the core of the problem. My view is that the pilots I grew up with were the top guns of the civil world. They needed to be. B747 quadruple engine failure. b744 turned upside down by intruder and lost 2 miles altitude in 90 seconds. Sioux City. Hudson River + a thousand more. All flown to the a safe landing, or least worst outcome as per Sioux City.
The thing is that however good the legendary pilots of yesteryear it is far safer now than in the past. I think there is a lot of selective memory and golden age fallacy going on.

I am not going to rehash the problems with MCAS but this was clearly behaviour of a system in the event of a single fault with a probability of a catastrophic outcome that was not small. You can argue that in the past the excellance of pilots meant that they would on average have handled it better, but it is irrelevant, it would still have a significant chance of causing a crash and it would still be considered an unacceptable design that must be rectified.
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Old 3rd Jun 2019, 12:31
  #149 (permalink)  
 
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My cockpit is full of protective systems that got developed because of past years top gun pilots who flew their aircraft into the ground, crashed with other aircraft or flew straight into thunderstorms.
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Old 3rd Jun 2019, 16:06
  #150 (permalink)  
 
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Salute!

As one of the "legendary" pilots of yesteryear along with yan and others,,,,,,,,,,

We would not be commenting/contributing here if we were just plain "lucky". As one of my mentors told me early on, "luck is when preparation meets opportunity". We encountered many problems to get here and we are still alive to comment, lucky or not. I prefer "or not".

Did our training help? You bet your a$$$.
Did we have great IP's? Ditto
Did most of us have good "hands"? Pretty sure I had/have. Too many flights when asking Joe Baggodonuts student "can you feel that?" "Feel what?". Gasp, this was gonna take some time......... Believe it or not, but I gor a poor grade in the T-37 for stall/spin entry! I protested, claiming that I was not supposed to stall or spin. Intentionally stalling and spinning wasn't high on my priority list, heh heh. I resented the buffet and wing rock you encountered when pulling back on the stick and then putting in rudder at the stall. Sheesh.

So I support the folks here that like better training. At the same time, I do not appreciate the Yeager types here that claim "Oh yeah, if that were me there would be no problem".

You do not know the problem until something you least expect happens when you least expect it, and there is no memory item to mitigate the situation. You must rely upon past experience and mental exercises you did when sitting in the barber chair or waiting for your physical blood test or...... I used those stoopid times to imagine a problem and what I would do. Worked for me......
+++++++++++++++++++++
I do not like a kludge soulution to the 737 MAX handling characteristics at high AoA, and those are below the stall AoA.

IMHO ( not so humble), Boeing needed an aerodynamic solution and not an bandaid that could activate when they least expected it to activate. And then remove the manual electric trim if the crew followed the procedure!!!

Gums sends....

Last edited by gums; 3rd Jun 2019 at 22:07.
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Old 3rd Jun 2019, 16:44
  #151 (permalink)  

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OK just an old fart but:
In the 1970's the company I joined demanded 2000 to sit in the right hand seat of a 737 and 5,000 for earliest move into the left.
Currently how many hours to sit in the right seat (the Ethiopean F/O Ahmed Nur Mohammod Nur, 25 had 361 hrs) and how many airlines now consider that 2000 hours is sufficient experience for the LHS.
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Old 3rd Jun 2019, 22:08
  #152 (permalink)  
 
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My airline has a minimum requirement of 1500 hours and minimum time in the company of 5 years.
Ryanair have a minimum requirement of 2900 hours.

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Old 3rd Jun 2019, 22:20
  #153 (permalink)  
 
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Salute!

To be very honest, I would want to know how many landings and approaches and shorthaul routes like the regional folks do versus the 6 or 8 hours of monitoring the gauges and then only taking the wheel for the flare, rollout and such.

If possible, I would also like to know how many hours flying with the A/P disabled and the FMS doofer FUBAR. You know the drill ....pull out all those charts and tune the nav stations and..........

Gums....
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Old 3rd Jun 2019, 22:33
  #154 (permalink)  
 
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@ Gums
Exactly, you put the hammer to the nail.
This automatization to take the "stupid" pilot out of the loop has gone too far. When the system fails, he simply does not know what to do any more.
One faulty wire, one loose connection, is all it takes to get the system out, and the pilot has no clue where, what, how.
Certainly when that "fail-safe" system starts giving contradicting information, and even more so when the pages of errors go so fast on and off screen that even a robot could not track all of them.

And we are doing the same thing in cars.
Gruise control
Automatic lane keeping
Automatic braking
Night vision
And when the system fails? ? ? We continue to being passengers wondring what is happening till impact.


In a previous post you talk about "feel" .
Where feel, what feel, with a digital control system?

PS; the 16 is the same thing. Where feel, what "feel"? I will always remember the loss of another one of our "B" models.
Ran out of speed, nose vertical up at 18.000ft, pilots looking outside at bandit during a BFM (Pilots survived after ejection at 6.000 ft)
There is no "feel" with the surfaces pressures in a digital airframe.

Last edited by Vilters; 3rd Jun 2019 at 22:49.
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Old 4th Jun 2019, 08:35
  #155 (permalink)  
 
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A June 2nd front page Seattle Times article goes “Fateful 737 MAX revamp left key players in the dark.” The sub-head says “Critical decisions on design certification were based on misguided assumptions.”

The article is devoted 100% then to the proposition that the MAX’s “fatal flaws” have been “traced to a breakdown late in the plane’s development, when test pilots, engineers and regulators were left in the dark about a fundamental overhaul to an automated system that would ultimately play a role in two crashes.” No mention is made of the ships new, larger, more powerful engines, and their placement vis a vis the airframe, as the true and FUNDAMENTAL cause of why the MAX flys “differently” at times than any of its brethren. So differently, in fact, that an entirely new system had to be invented to cope with what Boeing is subtly admitting is a major and certain “aerodynamic” (as Gums says) shortfall.

But as for test pilots being left in the dark? Far from it I would venture. The latter would have been first to witness the new “bucking bronco” do her “characteristics” thing as she kicked up her heals to their spurs. Unless they’d been warned what maybe to expect (?), it must have been pretty unsettling. But that would be another story.

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Old 4th Jun 2019, 08:49
  #156 (permalink)  
 
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Originally Posted by radken View Post

But as for test pilots being left in the dark? Far from it I would venture. The latter would have been first to witness the new “bucking bronco” do her “characteristics” thing as she kicked up her heals to their spurs. Unless they’d been warned what maybe to expect (?), it must have been pretty unsettling. But that would be another story.

That is an interesting speculation, and you have good reason to expect it to be true. BUT, if there had been test flights under the original development program in which MCAS was caused to activate erroneously and the pilots recovered the situation gracefully then I am certain that Boeing would have quoted the flight data by now.

As no example of successful recovery from erroneous MCAS activation in flight HAS been publicly given I am assuming that none had occurred prior to the JT and ET tragedies
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Old 4th Jun 2019, 11:22
  #157 (permalink)  
 
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Originally Posted by radken View Post

But as for test pilots being left in the dark? Far from it I would venture. The latter would have been first to witness the new “bucking bronco” do her “characteristics” thing as she kicked up her heals to their spurs. Unless they’d been warned what maybe to expect (?), it must have been pretty unsettling. But that would be another story.
The test pilots test flew the conditions for which MCAS was designed - an approach to stall. By all accounts MCAS performed as desired.

What they did not do, and what they may not have understood as being possible, was test fly the scenario where MCAS activates due to an erroneous AOA sensor input.
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Old 4th Jun 2019, 11:31
  #158 (permalink)  
 
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Thank you Yoko, that is my assumption also.

So, a question for those fluent in Certification, is there a requirement to demonstrate that the failure of a single component should result in a flyable aircraft?

If so the (and pace many pages of discussion with regard to whether the 'frame WAS flyable after an erroneous activation) the fact that it has not been demonstrated ought to have been a limiting factor. I assume here that the FAA had previously been satisfied that the failure of a single AOA vane would not trigger a dangerous condition.
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Old 4th Jun 2019, 11:47
  #159 (permalink)  
 
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Originally Posted by Maninthebar View Post

So, a question for those fluent in Certification, is there a requirement to demonstrate that the failure of a single component should result in a flyable aircraft?
I think the more germane question is whether anyone actually realized that a single-point failure had been introduced into the design after all the modifications. It appears that there were too many chefs with a hand in the MCAS design and no one stepping back to give it a thorough top to bottom review. We would like to think that during the design phase someone would have seen what has now become obvious to everyone, but given the time pressures and compartmentalization built into the process, I can also see how this might have been missed.
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Old 4th Jun 2019, 12:44
  #160 (permalink)  
 
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In reading the NYT article, the test pilots comments struck me as rather humurous..

Old school Boeing test pilot: aircraft doesnt feel right, add vortex tabs.

Millennial Boeing engineer: aircraft doesnt feel right, add software.

Another observation, from the onset, we were lead to believe MCAS was needed due to lift from the engine nacelles at high angle of attack. If the NYT article is correct, the test pilot noted issues with low speed stall.
It also noted that the original MCAS had G force component (that was removed) so that would encompass a whole additional set of conditions or parameters.

Reading and wordsmithing the Boeing press releases on testing the software fix, and waiting for FAA approval for a validation flight, leads me to believe that much of the "testing" is being done in the sim.

If all of this is correct, then this does not appear to me to be a simple software and/or minimal training adventure.

Last edited by Smythe; 4th Jun 2019 at 13:04.
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