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Boeing 737 Max8 Aircraft Crashes and Investigations [Part 1] 20

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According to the Equipment List, the AOA sensors are identical part numbers on the left and on the right. From looking at the wiring diagrams, the Sine and Cosine output leads of the resolver in each AOA sensor are wired one direction on the #1 system into the #1 stall warning computer inputs and swapped on the #2 system into the #2 stall warning computer inputs. This is likely how the design allows one part number AOA vane to be used on either side. I do not have access to the system design to discover if the #1 and #2 AOA outputs are ever compared to each other.
 
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I think that question is answered in the data previously presented. The two AoA sensors disagreed while the plane was still on the ground, yet, they continued into takeoff.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
 
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Apparently it is the same part number for both sides and they can be swapped.

And also in best practise when they are swapped out a full calibration of the system should be performed which would have indicated a issue.

The parts apparently don't have an offset hole or lug to ensure correct orientation on fitting.

As usual its the full circle of screw ups which have led to the accident.

Its an option when you buy the MAX if there is AoA indications in the cockpit and if there are then you will get a comparator error if the two of them disagree. But in certain flight situations its expected that they will disagree but not constantly 20degs with wings level in the climb. In the real world a BITE check at 80 knots would have stopped this accident in its tracks with a low speed abort.
 
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VE1BLL said:
CVR recovered.
Click to expand...
Good. There's a running conspiracy theory about that. I'm sure those guys will decide this is not the real CVR.

Brad Waybright

It's all okay as long as it's okay.
 
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Another case of journalists writing an article that can impress the layperson, but just reveals their ignorance to the informed reader. They say a lot about Boeing responding to competition and pressuring the FAA, but offer no evidence to back up the claim. While I have no doubt that Boeing and the FAA interact on many levels every single day, that doesn't mean that on this particular issue anyone twisted any arms or concealed any information.

...Boeing plans to release a software upgrade for the 737 Max, according to a person briefed on the matter...
Click to expand...
Yay, another secret source to boost your credibility.

The write-up isn't really that bad, but has nothing new to say that hasn't already been in the NYT for the past few months. If you hadn't been following up to now, that article would be a place to start but you would need much more to get a grip on what is actually known so far. For those who have been watching this, or who know how an airplane works, it isn't even that.
The included video is next to useless. It's like nobody has any idea how an autopilot (automatic flight control system) works, so how could they possibly know what's different about the MCAS?

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF
 
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some of you might find this pilots review of the Q400 amusing.... its pretty much spot on.


This iteration of the 1960/70's designs needs to stop and a full type recertification needs to occur with current standards. The crap we have to put up with in the Q400 just so that it keeps a common type rating with the rest of the DH4 types is just horrible. We could have had hot wing deicing, No condition levers just mode select buttons like the Saab 2000. But oh no crappy pneumatic boots and a cluttered cockpit made to look like a 100 but all the levers have micro switches under them instead of being connected to the system just so it a common rating for 100,200,300 and 400.
 
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I have to agree with Alistair Heaton that sometimes the desire to remain under an old Type Certificate can go to great "lengths". If you take a look at the two attached photos, you will see the beginning and the end of the DC-9 line. They are both under the same type certificate. The "only" differences are stretched fuselage, re-designed wings and entirely different engines. Other than that, they are identical! [That last statement was pure sarcasm - the interiors and the flight deck are entirely different as well.]
 
 https://files.engineering.com/getfile.aspx?folder=d55a151e-af49-4045-9645-9e0111bafb0f&file=DC-9-88_or_MD88.jpg
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debodine: Just use the
ice_screenshot_20160718-141231_lxjeqv.png
to directly paste your pictures into a thread. Do resize them down to around 1000 pixels wide.

DC-9-88_or_MD88_hackme.jpg




DC-9-14_x2q9qh.jpg




Keith Cress
kcress -
 
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"Other than that, they are identical! "

We call that a California remodel; so long as a single wall from the original house remains, you can demo the rest of the house and quadruple its size and it's not a new build. That seems apropos, since Douglas was a California company.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
 
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I'm not sure if this has been mentioned before, but I happened on an air crash investigations from QF72 a few weeks ago. Seemed very similar to this and resulted in modification to the programs to prevent sudden spikes from data not to cause the system to meltdown.

This (quite long) interview with the pilot concerned is enlightening as to the sheer helplessness they felt when dealing with a flight computer gone mad.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
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The flight controls in the Airbus airliners have been called "wishbones".
As in... "I wish I could go up" or "I wish I could go down" but it's up to the computer to decide if you will be allowed to do so.

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF
 
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To itsmoked:

Many thanks for the instruction. I was unaware of that capability. I am very grateful for your help!
 
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"...a report citing data from...the cockpit voice recorder, suggests the flight crew didn't even understand what they were fighting, and may have had no idea how to override the malfunctioning system."

Doomed Lion Air flight's pilots reportedly scoured Boeing 737 Max manual as plane went down

Apparently, there was an off-duty pilot just riding along on the plane's flight the day before, who was the only one that knew what to do, but unfortunately for the poor souls on Flight 610, he wasn't there the next day.
 
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enginesrus said:
Easy fix, just control the plane like they did in the DC-3 days.
Click to expand...

DC3: ~25,000 lb, 200 kn, piston power

737: ~190,000 lb, 450+ kn, jet power

Yeah those are aircraft that are comparable and should be compared from the standpoint of developing controls schemes.
 
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