Re: 737 Max 8 Simulators
Posted: Tue May 07, 2019 7:45 pm
What’s sim evaluation time?
http://www.avcanada.ca/forums2/
What’s sim evaluation time?
Answer: There definitely are differences. Here’s a few off the top of my head.confusedalot wrote: ↑Tue May 07, 2019 6:01 pmJust stumbled on this......
You are 100% right, hit the switches and everything gets disabled. One caveat, never flew the max, just did simulator stuff, but from what I know, you disable everything
It's old news now, the real problem is that Boeing did not tell anybody about the mcas.
Hell, even I did not know about it. You would figure that a sim evaluator would be provided with the information.
How is a sim evaluator supposed to do his job without information,?
How is a line pilot supposed to save the day with no knowledge?
Sad situation indeed
Finally someone who knows and understands what the MAX is capable off.sepia wrote: ↑Mon May 13, 2019 4:50 pm
Answer: There definitely are differences. Here’s a few off the top of my head.
MCAS runaway runs at the flaps down trim speed. MCAS only operates with flaps up, so it’s trimming down a much quicker rate than you’re trimming back at.
A stab trim runaway is coded in the Boeing binary as an electrical ground causing the trim to run continuously in the direction in which trim is applied first when the trim activates. Trimming in the opposite direction will stop the runaway, but will not trim counter to the runaway. So there’s no point in waiting to cutout the trim.
MCAS runaway can be stopped with yoke trim and it’s input can be reversed. It’s reversed at a lower speed as mentioned in point 1. So ideally you’d trim back to neutral before cutting out the trim with the drill.
Before someone wants to go nuts on the keyboard and tell me how wrong I am. Boeing made a multi hour presentation about this to a group I was a part of this month regarding the MAX. So unless somehow you’ve got better info than Boeing test pilots have, I’d save your keystrokes.
I'm surprised to hear that. I thought ALPA may even insist on some kind of master disconnect switch for the MCAS system. Something that would still allow normal use of the trim and autopilot but just no MCAS. Weren't ALPA responsible for the crash bar style autopilot disconnect switch on Boeings? Many people thought it was being overly cautious and paranoid about automation. But sometimes it's good for pilots to stand up to the engineers.
To be blunt, everything you said was wrong. Literally everything.L39Guy wrote: ↑Tue May 14, 2019 3:12 pm There is nothing stopping the use of the autopilot. In fact, it shuts MCAS off. Using the electric trim switches on the control column turns MCAS off too while in manual flight.
I think the idea is to keep things simple by having the same procedure for an MCAS event as a stab trim runaway, which MCAS is by definition - an uncommanded trim input to the stabilizer. An stab trim runaway or an MCAS event is not time to be diagnosing which is which; a common procedure for both makes the most sense.
Whoa, cowboy, just take it easy. I think you are misinterpreting my responses to the comments made by Daniel Cooper.sepia wrote: ↑Tue May 14, 2019 5:20 pmTo be blunt, everything you said was wrong. Literally everything.L39Guy wrote: ↑Tue May 14, 2019 3:12 pm There is nothing stopping the use of the autopilot. In fact, it shuts MCAS off. Using the electric trim switches on the control column turns MCAS off too while in manual flight.
I think the idea is to keep things simple by having the same procedure for an MCAS event as a stab trim runaway, which MCAS is by definition - an uncommanded trim input to the stabilizer. An stab trim runaway or an MCAS event is not time to be diagnosing which is which; a common procedure for both makes the most sense.
Step 2 of the runaway stabilizer drill states verbatim "do not re-engage the autopilot"
Using the electric trim doesn't turn MCAS off. Electric trim uses a higher trim priority and will override MCAS temporarily. The moment you stop trimming, if the MCAS engagement criteria still exist, MCAS will recommence trimming at the flaps down trim speed, where you were trimming with flaps up speed. You specified manual flight, the entire speed trim system, of which MCAS works within, can only work in manual flight. So it's not like there's an auto flight possibility for this to happen.
MCAS isn't uncommanded stabilizer trim by definition. You should never ever have a 737 into a nose up attitude anywhere near the MCAS engagement criteria. If you did, MCAS provides pitch stability. If you believe this is uncommanded trim, then by your definition the entire speed trim system is uncommanded, and thus should be cut out. You'd be unlikely to fly many legs with the trim cutout if that were the case.
MCAS isn't being removed in the 12.1.1 updates. It's simply having disengagement criteria added. You'll read all about them before the planes return to the line.
Sorry for coming in so hot there, but you've got some very fundimental lack or knowledge about MCAS and the speed trim system.
How has the new QRH page/procedure changed? Or are you just being pedantic and missing the point being (I might add, very well) made by L39?
That is false.
Gilles Hudicourt wrote: ↑Tue May 21, 2019 7:24 amThat 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 ?
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.....
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?Gilles Hudicourt wrote: ↑Tue May 21, 2019 7:24 amThat 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 ?
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.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.....
You brought up a very interesting point. It took 70 years of commercial flying before Boeing decided that an UAS drill was required ?
100% agree with every word Gilles!Gilles Hudicourt wrote: ↑Sun May 26, 2019 7:19 amYou 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.