737 Max 8 Simulators

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complexintentions
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Re: 737 Max 8 Simulators

Post by complexintentions »

Gilles Hudicourt wrote: Tue May 21, 2019 10:31 am The guys had taken off in Night VMC condition with scotch tape on all their Static ports.

The 737-8 accident crews had similar experiences.....


No. It was daylight VMC with the Ethiopian accident. Even with a delay to account for startle effect, an unreliable airspeed/ spurious stall warning should have been quite readily identified as false with visual reference, unlike the example you quote. Surely we can agree that things are a lot easier when you can see good old terra firma.

As your own account details, the Aeroperu had far more to deal with, given that their entire pitot/static system was compromised.I am not discounting the impact of multiple contradictory indications, only that the two situations are not comparable in scope.

I would suggest that in both situations, if you are completely overwhelmed go back to basics and fly pitch, power and attitude. Essentially, the Unreliable Airspeed memory items. Neither crew did this. 340 knots?!

Sometimes trying to do it "by the book" creates its own problems.
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Re: 737 Max 8 Simulators

Post by L39Guy »

Gilles Hudicourt wrote: Tue May 21, 2019 7:24 am
L39Guy wrote: Wed Apr 10, 2019 5:22 pm Confusedalot,

How would an MCAS failure look differently in a simulator compared to a stab trim runaway? What are the differences in the emergency drill?

Answer: there is no difference.
That is false.

1) The Standard Runaway trim fault does not have a stall warning and stick shaker associated with it.
2) The Standard Runaway trim fault is not associated with an IAS Disagree alert, which when it happens at take off, calls for the pilot to disconnect autopilot and auto thrust and maintain 10 degree nose up and 80% N1 (The MCAS fault kicks in at flaps up after the Stall warning and the IAS Disagree)
3) The Standard Runaway trim fault does not stop when you input some electric trim, pause a number of seconds, and -re-activate again, and so forth in a loop.

I read somewhere that the Ethiopian PIC had selected 235 in the speed window at some point, and then never touched the throttles after that, thinking the speed and power issue had been taken care of, when in fact the aircraft was at high power setting until impact. Had he previously disconnected the auto thrust as part of the Unreliable airspeed drill but forgot about it ?
I beg to differ. The UAS (stick shaker and IAS disagree) was present from the moment the aircraft lifted off, about two minutes before the flaps were raised and MCAS kicked. They had two minutes to do this drill in isolation and didn’t. It is important to note that the Lion Air incident crew did do the drill and both accident flights did not. How do you explain the UAS NNC NOT being performed in the first two minutes of these flights?

If UAS and MCAS occurred simultaneously you would have a valid point, they did not.

The SW B737 crew that dealt with the engine explosion and rapid depressurization had simultaneous failures, the MCAS aircraft did not.

What is a standard runaway trim emergency? A runaway trim is anytime uncommanded trim is being applied, continuous, intermittent, or whatever. This is common to to virtually all aircraft. The duration, source, cause and minutia of its characteristics is irrelevant in flight. But to your point, how about a trim failure caused by loose wire shorting out intermittently? Would you treat that as a runaway and shut the system off, per the Stab Trim Runaway or would you continue as it doesn’t meet the “standard” trim runaway. I know what I would do.
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Re: 737 Max 8 Simulators

Post by L39Guy »

Gilles Hudicourt wrote: Tue May 21, 2019 10:31 am When I was a 757 driver, I remember downloading and studying an accident report from an Aeroperu 757. I went through the FCOM to understand everything that happened.....

https://www.skybrary.aero/bookshelf/books/1719.pdf (This is an unofficial translation of the official accident report in Spanish)
The guys had taken off in Night VMC condition with scotch tape on all their Static ports. They crashed after 29 minutes and everyone died.
It should have been a standard Unreliable airspeed exercise, and the pilots could be accused of incompetence until you study the details (the captain had upwards of 20,000 hours) They were bombarded with so many and often contradictory bells, lights, EICAS messages, aural warnings that they eventually lost it and crashed. They no longer knew which warnings were valid and which had to be ignored. In the end, they trusted some that should have been ignored and ignored some that should have been trusted.
Their altimeters, airspeeds and VSIs were not working properly. But in addition to that, they had Wind Shear alarm, Rudder Ratio and Mach Speed Trim warnings, over speed warning, stick shaker and stall warning, Too Low Terrain, Sink Rate and maybe others that I missed. It was warning overload.

Yet all they had was an Unreliable Airspeed fault. Nothing else. It’s so easy to judge them and say that had they recognized it and dealt with it as per the QRH, they would have made it.

The 737-8 accident crews had similar experiences.....
The big difference between Aeroperu and the MAX situation is that there was no UAS drill prior to Aeroperu but there is one for the MAX. A UAS drill was one of the lessons learned from Aeroperu.
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Re: 737 Max 8 Simulators

Post by Gilles Hudicourt »

L39Guy wrote: Wed May 22, 2019 12:13 am The big difference between Aeroperu and the MAX situation is that there was no UAS drill prior to Aeroperu but there is one for the MAX. A UAS drill was one of the lessons learned from Aeroperu.
You brought up a very interesting point. It took 70 years of commercial flying before Boeing decided that an UAS drill was required ?
What made that change necessary ?

In basic aircraft design, an aircraft instrument panel is made to be redundant and there is always a backup system that allows you to survive in case of loss of any one system. A basic Cessna 172's panel has :
The magnetic compass (self contained)
An Airspeed Indicator (pitot tube and static port)
A Vertical Speed Indicator (static port)
A Directional gyro (Vacuum pump)
An Artificial Horizon (Vacuum Pump)
A Turn and Bank Indicator or a Turn Coordinator (Electrical)
A Stall warning (self contained)

The loss of either the Vaccum Pump, the electrical system, the pitot tube or the the static port will still leave enough instruments working to keep control of the aircraft. Pilots are taught very early to not only know what system powers what instrument but also to know which instruments they can trust and which they must remove from their scan once the failed system has been identified.

This was still true in early transport Category aircraft, even when the systems got more complex. The electrical systems for example became more complex and buses were introduced with electrical back ups. Some instruments needed an inverter to work on AC, while others were DC. Still pilots were taught which was which and knew exactly what instruments failed when a generator or an inverter was lost, and which ones remained operational.

This segregation was however lost at a certain stage of aircraft design. Today, in glass cockpits, all instruments are electrical, so a total loss of electricity would spell disaster. The electrical system became complex, so the failure of one instrument powered by one bus would not knock out the whole system. There are AC and DC buses, main buses, emergency buses, battery buses, bus ties etc.

But we still have as instrument sources the classic pitot tubes, static ports and AOA vanes. There are also new input sources such as IRS And GPS. When today's pilot looks at his instrument panel, can he really know with certainty which will work and which will not in the advent of the loss of a particular system ?

On the 737 NG, the loss of of the AOA probe affects the Indicated airspeed. Huh ?
In the Airbus 330, the VSI is hybrid Static-Port and IRS. Huh ?
In the Airbus 330, in case of unreliable airspeed, we are told to always trust the stall warning indication which is independent of the Pitot Static (like in most aircraft).
In the Boeing 737NG, we are told on the contrary NOT to trust the stall or over-speed warnings in case of and unreliable airspeed.

Now, because of the complexity of the aircraft systems and the way they are programmed into the aircraft software, we have failures of some systems which cause erroneous indications of other systems that at first impression are totally foreign to the failed system.

The AeroPeru 757 had one problem and one problem only. Clear scotch tape had been applied to all its static ports by those who had been tasked with cleaning the aircraft had installed to avoid spaying water in them after they had been asked to wash the aircraft and warned not to spray water in the static ports. They forgot to remove the tape, and the flight crew who did the walk around at night, failed to see the clear scotch tape over all the static ports.

What should have been a clear case of a pitot-static problem had this jet been an older 737 or DC-8, turned into a nightmare for the 20,000 hour captain because of the conflicting and multiple unrelated warnings he experienced after take off.

Airspeed Indication Problem
VSI indication problem
Wind shear warning
Stall Warning
Overspeed warning
Rudder Ratio Warning
MAch TRim Warning
GPWS warnings......

This is what happened to AeroPeru
This is what happened to Air France 447

I don't blame the 737 MAX pilots one bit for their failure to save the aircraft.
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Last edited by Gilles Hudicourt on Wed May 29, 2019 8:47 am, edited 8 times in total.
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Re: 737 Max 8 Simulators

Post by dumbbell daddy »

Gilles Hudicourt wrote: Sun May 26, 2019 7:19 am
L39Guy wrote: Wed May 22, 2019 12:13 am The big difference between Aeroperu and the MAX situation is that there was no UAS drill prior to Aeroperu but there is one for the MAX. A UAS drill was one of the lessons learned from Aeroperu.
You brought up a very interesting point. It took 70 years of commercial flying before Boeing decided that an UAS drill was required ?
What made that change necessary ?

In basic aircraft design, an aircraft instrument panel is made to be redundant and there is always a backup system that allows you to survive in case of loss of one system. A basic Cessna 172"s panel has :
The magnetic compass (self contained)
An Airspeed Indicator (pilot tube and static port)
A Vertical Speed Indicator (static port)
A Directional gyro (Vacuum pump)
An Artificial Horizon (Vacuum Pump
A Turn and Bank Indicator or a Turn Coordinator (Electrical)
A Stall warning (self contained)

The loss of either the Vaccum Pump, the electrical system, the pitot tube or the the static port will still leave enough instruments to keep control of the aircraft. Pilots are taught very early to not only know what system powers what instrument but also to know which instruments they can trust and which they must remove from their scan once the failed system has been identified.

This was still true in early transport Category aircraft, even when the systems got more complex. The electrical systems became more complex and buses were introduced with electrical back ups. Some instruments needed an inverter to work on AC, while others were DC. Still pilots were taught which was which and knew exactly what instruments failed when a generator or an inverter was lost, and which ones remained operational.

This segregation was lost at a certain stage of aircraft design. Today, for one thing, all instruments are electrical, so a total loss of electricity would spell disaster. So the electrical system became complex, so the failure of one system powered by one bus would not knock out the whole system. There are AC and DC buses, main buses, emergency buses, battery buses etc.

But we still have the classic pitot tubes, static ports and AOA vanes. There are new input sources such as IRS And GPS. When today's pilot looks at his instrument panel, can he really know which will work and which will not in the advent of the loss of a particular system ?

On the 737 NG, the loss of of the AOA probe affects the Indicated airspeed. Huh ?
In the Airbus 330, the VSI is hybrid pitot-Static and IRS. Huh ?
In the Airbus 330, in case of unreliable airspeed, where are told to always trust the stall warning indication which is independent of the Pitot Static (like in most aircraft).
In the Boeing 737NG, we are told on teh contrary not to trust the stall or overspeed warning in case of and unreliable airspeed.

Now, because of the complexity of the aircraft systems and the way they are programmed into the aircraft software, we have failures of some systems which cause erroneous indications of other systems that are totally foreign.

The AeroPeru 757 had one problem and one problem only. There was clear scotch tape on all its static ports, that those who had been tasked with cleaning the aircraft had installed to avoid spaying water in them after they had been asked to wash the aircraft and warned not to spray water in the static ports. They forgot to remove the tape, and the flight crew who did the walk around at night, failed to see the clear scotch tape over all the static ports.

What should have been a clear case of a pitot-static problem had this jet been an older 737 or DC-8, turned into a nightmare for the 20,000 hour pilot because of the conflicting and multiple unrelated warnings this 757 crew received after take off.

Airspeed Indication Problem
VSI indication problem
Wind shear warning
Stall Warning
Overspeed warning
Rudder Ratio Warning
MAch TRim Warning
GPWS warnings......

This is what happened to AeroPeru
This is what happened to Air France 447

I don't blame the 737 MAX pilots one bit for their failure to save the aircraft.
100% agree with every word Gilles!
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Re: 737 Max 8 Simulators

Post by L39Guy »

Gilles,

Excellent dissertation.

I would add, if I recall my A330 days correctly, an inter relationship between the aircraft clock and the flap motors, or something like that.

Regardless of the inter relationships and complexity, it still boils down to the pilot to deal with anticipated and unanticipated failures such as double engine failures (USAir), engine failure/rapid decompression (SW), etc. In the MAX case, it was a stick shaker(implying a stall) with other things such as IAS Disagree. With three independent airspeed sources combined with the feel of an aircraft, a pilot should be able to sort out whether the aircraft is stalling or not (mushy feel to the flight controls) or whether the airspeed is unreliable and which one by comparing the three airspeed indicators.

But even if you can't determine what airspeed indicator is erroneous, Boeing provides a checklist that gives you a pitch and power combination that will guarantee that you will continue flying (with flaps extended 10 degrees pitch/85% power). That is exactly what the Lion Air incident crew did and in the process they were able to control the speed of the aircraft, were able to manually trim the aircraft and fly the aircraft for an hour and a half with unreliable airspeed and manual trim. The Lion Air crew the next day were presented with the same circumstance and did not do the UAS drill, which in designed precisely for this kind of event, regardless of how complex the aircraft systems may be.

Five months later, with the benefit of the Airworthiness Directive providing even more details of the MCAS issue including the unreliable airspeed, the crew did not even to the UAS drill, didn't control the speed of the aircraft, were unable to trim the aircraft manually while flying around at 340+ Kts.

Complex aircraft systems or not, at the end of the day, one still has to fly the airplane even if means going back to basics.
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Re: 737 Max 8 Simulators

Post by complexintentions »

No one is trying to "blame" anyone, not in the finger-pointing sense. But to suggest that the crews of any of the accident flights mentioned do not bear a measure of responsibility is foolhardy. MCAS did not cause the crew to reach 340 kts. The AF FO pulling full aft sidestick for minutes at a time was not caused by the pitot-static system freezing up. This is simply a concrete application of the "it's not who's right, but what's right" philosophy. It is not a personal attack on the pilots. We are only human and no one wants to see a colleague lose their life.

The point has been well-made and no one is arguing against the fact that the complexities of modern aircraft design have introduced new challenges for flight crew. But a dissertation on the differences of 70 years ago and now is not particularly helpful. I'm quite confident we're not going back to Cessna 172 level of simplicity machines just to accommodate the lowest common denominator of pilot knowledge and abilities.

Achieving the safe outcome of a flight is a joint responsibility of all involved parties, which in the case of MCAS the Boeing engineers failed miserably to fulfill their role of designing a properly fault-tolerant system. But I respectfully reject the implication that this absolves flight crews from our responsibility to be the last line of defence and not "to blame one bit".

Too much faith in engineering, too much reliance on tech. Why have we forgotten that the actual physics of flight have never changed?
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Re: 737 Max 8 Simulators

Post by L39Guy »

This article from a trade magazine, rather than a newspaper, nicely describes the issue.

https://m.aviationweek.com/business-avi ... eb43628438
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Re: 737 Max 8 Simulators

Post by Gilles Hudicourt »

L39Guy wrote: Mon May 27, 2019 6:11 pm
I would add, if I recall my A330 days correctly, an inter relationship between the aircraft clock and the flap motors, or something like that.
Quite true. Between the aircraft clock and the wingtip brakes, a device meant to prevent asymmetrical flaps or slats. If during preflight, while setting the aircraft clock, the pilot inadvertently advances the date by 24 hours, the wingtip brakes activate, and maintenance has to be called to unlock them.


L39Guy wrote: Mon May 27, 2019 6:11 pm But even if you can't determine what airspeed indicator is erroneous, Boeing provides a checklist that gives you a pitch and power combination that will guarantee that you will continue flying (with flaps extended 10 degrees pitch/85% power). That is exactly what the Lion Air incident crew did and in the process they were able to control the speed of the aircraft, were able to manually trim the aircraft and fly the aircraft for an hour and a half with unreliable airspeed and manual trim. The Lion Air crew the next day were presented with the same circumstance and did not do the UAS drill, which in designed precisely for this kind of event, regardless of how complex the aircraft systems may be.
The Lion Air crew you mention, the one that survived, had a third pilot on the jumpseat who did not have his hands full and who called what he saw to the flying crew.

I can no longer find the source, but I read somewhere that the Ethiopian pilot selected 235 kts in the Speed Window at one point, so thought he had taken care of the speed and power problem. The aircraft remained at Take Off Power while the Speed Window had been selected at 235. After that, he needed both hands to keep the aircraft from plowing into the ground, and did not have a third hand to control the throttles. Just before the impact, he even asked his colleague to help him pull back on the yoke, but they were overpowered by the movable horizontal stabilizer.
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Re: 737 Max 8 Simulators

Post by Gilles Hudicourt »

L39Guy wrote: Tue May 28, 2019 7:57 pm This article from a trade magazine, rather than a newspaper, nicely describes the issue.

https://m.aviationweek.com/business-avi ... eb43628438
Very good article, except the author seems to be a bit geographically challenged. He first talks of the "Indonesian" and "African" flights, then refers to the Ethiopian aircraft as the "North African" aircraft.
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Re: 737 Max 8 Simulators

Post by delta1 »

"If the runaway continues:
Stabilizer trim wheel..........Grasp and hold"


Not physically possible. You will rip the skin off your hand and most likely break a few knuckles in the process.
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Re: 737 Max 8 Simulators

Post by L39Guy »

Yes, it took the 3rd pilot on the Indonesian incident flight to tell them to turn off the stab trim; they did the UAS drill immediately after takeoff without any input from the third pilot.

According to the preliminary report of the ET accident, the captain did as for 233 its with FL Change about 90 seconds after takeoff . Never happened. But, it was a UAS from the moment the aircraft took off which requires turning off all of the auto stuff and manually controlling the throttles.
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Re: 737 Max 8 Simulators

Post by L39Guy »

delta1 wrote: Fri May 31, 2019 7:35 am "If the runaway continues:
Stabilizer trim wheel..........Grasp and hold"


Not physically possible. You will rip the skin off your hand and most likely break a few knuckles in the process.
The PNF slides his seat back and uses the bottom of his foot to stop the wheel. That’s how I was trained.
The stab trim also stops for 5 seconds after 10 seconds of MCAS burst.
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Re: 737 Max 8 Simulators

Post by FL410AV8R »

L39Guy wrote: Sat Jun 01, 2019 7:26 am
The PNF slides his seat back and uses the bottom of his foot to stop the wheel. That’s how I was trained.
The stab trim also stops for 5 seconds after 10 seconds of MCAS burst.
So during this maelstrom of misinformation and fighting for control of the aircraft the PNF just slides his/her seat back, away from the control column and any assistance required by the PF and places their foot on the trim wheel. Yea that is gonna happen. In 5 years of simulator instructing/training/checking I have never seen any reference to this "foot method" in any Boeing literature, official or otherwise, although I have seen some Chinese pilots demonstrate it on YouTube recently. It is very easy when planned and with no other distractions.

I think you are over-simplifying a very complex and dynamic situation with the benefit of an armchair and hindsight. MCAS still does not appear in the B737MAX FCOM anywhere but in the definitions section.

Also, a 5 second break after 10 seconds of high-speed trim is not much of a reprieve, do you realize how far out of trim the aircraft will be after 10 seconds of non-stop high-speed ND trim. Try it sometime on the ground, run the trim with the flaps up and then extend the flaps and see the difference. 10 seconds of high-speed ND trim will take the stab trim from within the normal range to well outside it, actually close to the electric trim ND limit.
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Re: 737 Max 8 Simulators

Post by goingnowherefast »

That's an interesting control method. Foot on the trim wheel. Perhaps they should use the crash axe? Giant wrecking bar? I can't understand how anybody thought that was okay to cerfity. No wonder the thing is grounded.

The next 737 generation will require a hammer to bash the yoke around because it's so hard to move too?

My sympathy to the pilots, the airplane is barely controllable in manual flight with all automation off, can't imagine an emergency...well it's not controllable in an emergency.
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Re: 737 Max 8 Simulators

Post by laserstrike »

FL410AV8R wrote: Sat Jun 01, 2019 9:41 am
L39Guy wrote: Sat Jun 01, 2019 7:26 am
The PNF slides his seat back and uses the bottom of his foot to stop the wheel. That’s how I was trained.
The stab trim also stops for 5 seconds after 10 seconds of MCAS burst.
So during this maelstrom of misinformation and fighting for control of the aircraft the PNF just slides his/her seat back, away from the control column and any assistance required by the PF and places their foot on the trim wheel. Yea that is gonna happen. In 5 years of simulator instructing/training/checking I have never seen any reference to this "foot method" in any Boeing literature, official or otherwise, although I have seen some Chinese pilots demonstrate it on YouTube recently. It is very easy when planned and with no other distractions.

I think you are over-simplifying a very complex and dynamic situation with the benefit of an armchair and hindsight. MCAS still does not appear in the B737MAX FCOM anywhere but in the definitions section.

Also, a 5 second break after 10 seconds of high-speed trim is not much of a reprieve, do you realize how far out of trim the aircraft will be after 10 seconds of non-stop high-speed ND trim. Try it sometime on the ground, run the trim with the flaps up and then extend the flaps and see the difference. 10 seconds of high-speed ND trim will take the stab trim from within the normal range to well outside it, actually close to the electric trim ND limit.
He probably just watched that YouTube video where they do that in a sim to see if it works. Doubt he's actually a 37 pilot.
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Re: 737 Max 8 Simulators

Post by L39Guy »

FL410AV8R wrote: Sat Jun 01, 2019 9:41 am So during this maelstrom of misinformation and fighting for control of the aircraft the PNF just slides his/her seat back, away from the control column and any assistance required by the PF and places their foot on the trim wheel. Yea that is gonna happen. In 5 years of simulator instructing/training/checking I have never seen any reference to this "foot method" in any Boeing literature, official or otherwise, although I have seen some Chinese pilots demonstrate it on YouTube recently. It is very easy when planned and with no other distractions.

I think you are over-simplifying a very complex and dynamic situation with the benefit of an armchair and hindsight. MCAS still does not appear in the B737MAX FCOM anywhere but in the definitions section.

Also, a 5 second break after 10 seconds of high-speed trim is not much of a reprieve, do you realize how far out of trim the aircraft will be after 10 seconds of non-stop high-speed ND trim. Try it sometime on the ground, run the trim with the flaps up and then extend the flaps and see the difference. 10 seconds of high-speed ND trim will take the stab trim from within the normal range to well outside it, actually close to the electric trim ND limit.
I spent 16 years on the B737-200 and I recall doing the Stab Trim Runaway drill a number of times including a couple where we used the foot method because, as noted earlier, trying to stop the trim wheel with your bare hands would take a couple of layers of skin off or create a second emergency, Smoke in the Cockpit, from the burning skin.

I think the fact that MCAS was or was not in the FCOM is a bit of a red herring. An MCAS runaway exhibits the identical characteristics to a stab trim runaway. In one way it is gentler - it goes in 10 second bursts; a conventional stab trim runaway would go continuously until the screw jacks hit the stops placing the aircraft even farther out-of-trim, faster.
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Re: 737 Max 8 Simulators

Post by L39Guy »

laserstrike wrote: Sat Jun 01, 2019 10:38 am He probably just watched that YouTube video where they do that in a sim to see if it works. Doubt he's actually a 37 pilot.
16 years, about 10,000 hours on the B737-200.
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Re: 737 Max 8 Simulators

Post by florch »

goingnowherefast wrote: Sat Jun 01, 2019 9:45 am That's an interesting control method. Foot on the trim wheel. Perhaps they should use the crash axe? Giant wrecking bar? I can't understand how anybody thought that was okay to cerfity. No wonder the thing is grounded.

The next 737 generation will require a hammer to bash the yoke around because it's so hard to move too?

My sympathy to the pilots, the airplane is barely controllable in manual flight with all automation off, can't imagine an emergency...well it's not controllable in an emergency.
This is untrue. It flies like any other Boeing without automation. Not difficult.

And while I won't let Boeing off the hook, and there a couple other holes in the swiss cheese, this isn't even a discussion if memory items are completed. But that may lead to an even bigger consumer confidence issue - flight deck standards in third world countries.
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Re: 737 Max 8 Simulators

Post by L39Guy »

goingnowherefast wrote: Sat Jun 01, 2019 9:45 am My sympathy to the pilots, the airplane is barely controllable in manual flight with all automation off, can't imagine an emergency...well it's not controllable in an emergency.
If it was “barely controllable” how did the crew of the Lion Air incident flight (the day before the accident flight on the same aircraft) manage to not only control the aircraft but fly it for an hour and a half to the original destination with manual trim? Answer: they flew the aircraft during the MCAS trim event by controlling the speed of the aircraft and hence the flight control forces required for manual trim.
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