Forums > General Discussion   Shooting the breeze...

737 max

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Created by southace > 9 months ago, 13 Mar 2019
rod_bunny
WA, 1089 posts
19 Mar 2019 6:23PM
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Paddles B'mere said..
I'd be surprised if a lot of systems data isn't transmitted in real time via satellite directly to aircraft and engine manufacturers these days.


It is.. Rolls Royce do it..
www.rolls-royce.com/products-and-services/civil-aerospace.aspx

www.forbes.com/sites/johngoglia/2014/03/13/aircraft-engine-monitoring-how-it-works-and-how-it-could-help-malaysia-air-370-crash-investigtors/#5d68930e7620

Paddles B'mere
QLD, 3586 posts
19 Mar 2019 8:31PM
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The engine manufacturers and also Boeing have proprietary monitoring systems for aircraft and power plants that store and then send data back to the factory, they used to do it in bursts via ground stations (when available) but I wondered whether they may have moved to satellite comms by now. Engine maintenance is big money FN, they love to know when they need to spend big money so they don't spend it before they need to.

FormulaNova
WA, 14646 posts
19 Mar 2019 7:29PM
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Paddles B'mere said..
The engine manufacturers and also Boeing have proprietary monitoring systems for aircraft and power plants that store and then send data back to the factory, they used to do it in bursts via ground stations (when available) but I wondered whether they may have moved to satellite comms by now. Engine maintenance is big money FN, they love to know when they need to spend big money so they don't spend it before they need to.


Yeah, I guess this makes sense. I know that this was one of the ways they figured out where MH370 could have been, but I didn't think there was much data sent. although even a 'lot' of data for engine is probably not much.

Chris6791
WA, 3271 posts
19 Mar 2019 9:07PM
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Rolls Royce and GE have had real time engine monitoring for around a decade or more.

Paddles B'mere
QLD, 3586 posts
20 Mar 2019 1:56PM
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Yep, it's common in the transport industry. Many powerplant suppliers to machinery use telemetry data for performance monitoring an also to make maintenance more cost efficient (and also transfer liability if the powerplant is used incorrectly )

nicephotog
NSW, 251 posts
22 Mar 2019 9:13PM
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Personally, i think the way some things drive stairs on the tarmac to 737's blind in second rate airports makes vertical angle of attack sensor vanes throw away material !

Take a look where the stairs are !!!
globalnews.ca/video/4623182/lion-air-passenger-films-final-moments-before-boarding-ill-fated-flight-610-in-jakarta





Most western pilots that are properly trained say that happens in the 737 but they know which button to switch off the auto-console so it's a problem but just not life threatening in the terms of second world pilots because its as simple as a switch, whereas the second world cheap trained pilots just don't fully understand the whole system and pieces.

Harrow
NSW, 4521 posts
22 Mar 2019 10:18PM
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^^^ There's some sort of anti-gravity thing happening at 0:33.

Harrow
NSW, 4521 posts
23 Mar 2019 11:59AM
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Oh crap, now it turns out that even though there were two angle of attack sensors, the MCAS system only got input from one of them, unless you paid extra for the optional feature that looked for a discrepancy in the measurement from each of them. So, multi-million dollar passenger Jet liner is sold with a known single point of failure, and you need to pay extra to get the safe version. Seriously, there is no criminal negligence or liability here?

arstechnica.com/information-technology/2019/03/boeing-sold-safety-feature-that-could-have-prevented-737-max-crashes-as-an-option/

rod_bunny
WA, 1089 posts
23 Mar 2019 10:27AM
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Harrow said..
Oh crap, now it turns out that even though there were two angle of attack sensors, the MCAS system only got input from one of them, unless you paid extra for the optional feature that looked for a discrepancy in the measurement from each of them. So, multi-million dollar passenger Jet liner is sold with a known single point of failure, and you need to pay extra to get the safe version. Seriously, there is no criminal negligence or liability here?

arstechnica.com/information-technology/2019/03/boeing-sold-safety-feature-that-could-have-prevented-737-max-crashes-as-an-option/


Probably needed to tell the pilots they changed stuff as well....

arstechnica.com/information-technology/2018/11/indonesia-737-crash-caused-by-safety-feature-change-pilots-werent-told-of/


The Operational Manual Bulletin sent out by Boeing on November 6 provides procedures for dealing with that sort of situation, but no prior training provided by Boeing ever mentioned the automated system.

[Update 4:30 pm ET] The text of Boeing's bulletin read:

This bulletin directs flight crews to existing procedures to address this condition. In the event of erroneous AOA data, the pitch trim system can trim the stabilizer nose down in increments lasting up to 10 seconds. The nose down stabilizer trim movement can be stopped and reversed with the use of the electric stabilizer trim switches but may restart 5 seconds after the electric stabilizer trim switches are released. Repetitive cycles of uncommanded nose down stabilizer continue to occur unless the stabilizer trim system is deactivated through use of both STAB TRIM CUTOUT switches in accordance with the existing procedures in the Runaway Stabilizer NNC. It is possible for the stabilizer to reach the nose down limit unless the system inputs are counteracted completely by pilot trim inputs and both STAB TRIM CUTOUT switches are moved to CUTOUT.Additionally, pilots are reminded that an erroneous AOA can cause some or all of the following indications and effects:- Continuous or intermittent stick shaker on the affected side only.
- Minimum speed bar (red and black) on the affected side only.
- Increasing nose down control forces.
- Inability to engage autopilot.
- Automatic disengagement of autopilot.
- IAS DISAGREE alert.
- ALT DISAGREE alert.
- AOA DISAGREE alert (if the AOA indicator option is installed)
- FEEL DIFF PRESS light.In the event an uncommanded nose down stabilizer trim is experienced on the 737 - 8 / - 9, in conjunction with one or more of the above indications or effects, do the Runaway Stabilizer NNC ensuring that the STAB TRIM CUTOUT switches are set to CUTOUT and stay in the CUTOUT position for the remainder of the flight.



Handy info to have prior to takeoff??

kk
WA, 947 posts
23 Mar 2019 11:44AM
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I found this video informative

Stuthepirate
SA, 3589 posts
23 Mar 2019 3:58PM
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There was an interesting discussion on ABC radio a few weeks back where one of the "experts" stated there will be a movement back to supersonic commercial passenger flights within the next decade.
Predicted flight times to London from Aus around 8hrs
LA in under 6

Paddles B'mere
QLD, 3586 posts
23 Mar 2019 3:31PM
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So if Boeing's "solution" is to fit a light that indicates a sensor fault, does that mean that previously there was no way of indicating a sensor fault to the pilot????

I find it astounding that a civilian airliner with maybe a couple of hundred people aboard doesn't have some sort of sensor failure monitoring and indication system for the operator, yet a dumb@rse coal conveyor that is only ever accessed by highly trained technicians has to have a safety system that fully self monitors all of it's equipment and sensors.

kk
WA, 947 posts
23 Mar 2019 3:42PM
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^^^ Did you just ask a question then assume an answer all in one post?

Paddles B'mere
QLD, 3586 posts
23 Mar 2019 6:29PM
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Nope, I was asking a question. I was reading in the press that a proposed solution is a previous "option" to have a light that informs the captain of a sensor failure. It seems wild to me that this "feature" isn't normal considering that sensor failure feedback is very normal and in fact mandatory for the safety systems of the most basic of industrial equipment here in Australia.

www.abc.net.au/news/2019-03-22/boeing-plans-to-reverse-optional-safety-feature-on-737-max-fleet/10928066

kk
WA, 947 posts
23 Mar 2019 6:59PM
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From what I have read there are plenty of indicators that there is a problem with the auto trim, spinning trim wheels being the most obvious, the pilots need to switch off the electric trim, a feature that has been there since the early years. So now they will have a warning light too, but will they know what to do?

There are a lot of people flying planes that don't really know how to fly when the auto pilot isn't working as it should.

Paradox
QLD, 1326 posts
4 Apr 2019 9:48AM
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The Max 8 is doomed. It was a fudge to start with and needed fudges to fix the consequences from the fudges. You can blame pilots who should have been better trained and faulty sensors, but the problems can be traced back to the design of that model.

Boeing were caught with their pants down by not committing to designing a whole new aircraft to replace the 737 in response to the use of larger diameter fuel efficient engines. To fit them on a 737 and still maintain ground clearance they had to mount them forward on the wing. Flight dynamics changed and computer systems had to be designed to keep the plane flying properly. Fudges on fudges and poor decisions on poor decisions.

Now no one will buy the Max 8, and they will be forced to accelerate the design and construction of a new plane at great cost, while market share goes to their competitors.

Negligence and tragic loss of life aside, it will be used as an example in future of how poor decisions made to maximise margins now can have company killing ramifications down the track.

Paddles B'mere
QLD, 3586 posts
4 Apr 2019 10:27AM
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That's a brutal assessment Paradox, but possibly true. It's a commercial disaster spawned from the engineering maybe not being able to deliver a solution that suited their business plan. I don't think it will have "company killing ramifications" because Boeing have gobbled up most of their competitors and are a mega corporation with ongoing large military and civilian contracts. But if this had happened to Boeing a couple of decades ago things would possibly been quite different. Either way, it's going to cost them a packet in penalties and damages plus even more in market share and market confidence ............. it's a true commercial disaster for them.

Hardcarve1
QLD, 548 posts
4 Apr 2019 4:58PM
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Paradox said..
The Max 8 is doomed. It was a fudge to start with and needed fudges to fix the consequences from the fudges. You can blame pilots who should have been better trained and faulty sensors, but the problems can be traced back to the design of that model.

Boeing were caught with their pants down by not committing to designing a whole new aircraft to replace the 737 in response to the use of larger diameter fuel efficient engines. To fit them on a 737 and still maintain ground clearance they had to mount them forward on the wing. Flight dynamics changed and computer systems had to be designed to keep the plane flying properly. Fudges on fudges and poor decisions on poor decisions.

Now no one will buy the Max 8, and they will be forced to accelerate the design and construction of a new plane at great cost, while market share goes to their competitors.

Negligence and tragic loss of life aside, it will be used as an example in future of how poor decisions made to maximise margins now can have company killing ramifications down the track.


This is true from what I have read and was driven by one of many reasons but also from the need not to have a new plane that needed new training of pilots. By keeping the 737 platform and doing a cut and hack, airlines would not need the cost of training their existing pilots to fly them.
The tail jack screw problem which looks to be the cause of both accidents did not have any warnings on the dash but was available as an upgrade with warnings but apparently most airline do not purchase the upgrade. Something about pilot information overload is one reason not.

Chris6791
WA, 3271 posts
5 Apr 2019 6:28PM
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Failed tail jack screw?? That was Alaskan 261 from nearly 20 years ago? These latest two appear to be a faulty angle of attack sensors and how they interacted with the software controlling the pitch of the aircraft?



This guy appears to explain it well, especially if you want to bypass the media beat-up on the 'optional extra' fault light for the angle of attack sensor.

With 5000 max on order these two crashes are a short term PR and logistical nightmare for Boeing. Hardly a company killer. The Max will fly again and within a few news cycles the dead will be buried and all is forgotten except for a couple of Wikipedia pages and a memorial somewhere. Harsh but true; unless they lose a third one...

Paradox
QLD, 1326 posts
10 Apr 2019 4:26PM
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Chris6791 said..
With 5000 max on order these two crashes are a short term PR and logistical nightmare for Boeing. Hardly a company killer. The Max will fly again and within a few news cycles the dead will be buried and all is forgotten except for a couple of Wikipedia pages and a memorial somewhere. Harsh but true; unless they lose a third one...


I have no doubt the max will be made airworthy. The issue is that you now have the media and public being bombarded by reports that indicate there is a significant problem in the way at least one part of the plane was designed and approved. Trust is gone and is not easily gained back.

The max is easily identifiable by the winglets.....and people can see the plane assigned to a route when they book. If the public refuse to fly in it, it will significantly effect an airlines decision to fly it and would be grounds to cancel orders. Don't underestimate the power of public opinion over logic or truth in today's world.

Maybe it isn't a company killer in this case as Boeing is huge and can probably absorb the fallout, my point was it is an example that "can" be a company killer and probably would be for a smaller manufacturer.

Chris6791
WA, 3271 posts
10 Apr 2019 3:09PM
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Don't underestimates the public's willingness to take a cheap flight over safety issues.



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Forums > General Discussion   Shooting the breeze...


"737 max" started by southace