s543
in service - 2 years
Posts: 3,957
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Post by s543 on Apr 3, 2019 21:03:19 GMT 1
Baroque, we are discussing this piece of information in the 'Lion Air crash' thread. That the repair was made in the USA is unconclusive : we don't know whether or not Lion's maintenance made any mistake, or whether or not faulty sensors were the cause of erroneous indications in the first place. Perhaps you are still the only person believes maintenance from JT still comes into play. Put JT flight aside, ET flight didn't have any issue reported in prior flight. As soon as AOA sensor failed, the plane is gone. Unless you are telling me maintenance can accurately predict AOA is going to fail. Otherwise, I still don't see how maintenance come into play ..... NO REDUNDANCY in such powerful flight control logic is the most unacceptable fact that Boeing needs to take responsibility at. I just wonder if we would see those : - Managers-engineers that decided to design the MCAS as is designed - Boeing workers who did the certification work instead of FAA - The FAA personel who did signed on it - The BO management who is in the end responsible To finish in the JAIL ?
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s543
in service - 2 years
Posts: 3,957
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Post by s543 on Apr 3, 2019 21:05:56 GMT 1
By the way we do have more threads with the same themes going on - shouldn't those be put together ? so we do not have pieces of the same discussions in various places ?
Maybe one of the moderators might do that ?
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philidor
in service - 6 years
Posts: 8,950
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Post by philidor on Apr 4, 2019 10:17:29 GMT 1
Thank you, Kevin, that Leeham story was aired after I posted the Guardian article, which indeed seems ill-founded. So, what this means is that Boeing's procedure doesn't work because it relies on manual trim, which seems to be impossible at high speed. That's a terrible conclusion for Boeing ! Now comes one major question : the modest and reasonable changes they proposed in their latest presentation are they sufficiently changing the big picture ? I now doubt it. If it's not enough, what else can they do ? I have no idea, but I hope they have !
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Post by peter on Apr 4, 2019 10:17:37 GMT 1
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mjoelnir
in service - 2 years
Posts: 4,089
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Post by mjoelnir on Apr 4, 2019 10:20:23 GMT 1
CNN on the press conference regarding the release of the preliminary report on the crash. edition.cnn.com/africa/live-news/ethiopian-airlines-black-box-report/index.htmltwo statements that I find important: 1. Investigators have not identified any damage to aircraft sensors in relation to crash quote: “We can confirm that we haven’t found any foreign object damage,” Amdeye Ayalew, AIB investigation chairman, told reporters at a news conference on Thursday, speaking through a translator. 2. Preliminary report says crew 'performed all procedures repeatedly' quote: The preliminary report finds that the Ethiopian Airlines crew "performed all procedures repeatedly provided by the manufacturer but were unable to control the aircraft," according to Ethiopian safety investigators in the capital Addis Ababa.I would say what many have been talking about, Boeing is in problems for designing an unsafe frame.
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philidor
in service - 6 years
Posts: 8,950
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Post by philidor on Apr 4, 2019 10:51:06 GMT 1
Baroque, we are discussing this piece of information in the 'Lion Air crash' thread. That the repair was made in the USA is unconclusive : we don't know whether or not Lion's maintenance made any mistake, or whether or not faulty sensors were the cause of erroneous indications in the first place. Perhaps you are still the only person believes maintenance from JT still comes into play. Aircraft crashes almost always have more than one cause, they result from a chain of events. This is what you seem to forget. I wasn't accusing maintenance, and rejecting any other factor, I was claiming that we couldn't at that stage leave Lion Air's maintenance entirely off the hook - as you did in your post - since the root cause of the crash might have been the failure of a poorly installed sensor. For the sake of clarity, the root cause is the initial factor in the chain of events, not necessarily the most important one. ABC news claims that there actually was a sensor failure in the ET crash (this is the first time sensor failure is stated as a fact, not a supposition), caused by either a bird strike or foreign object dammage. Mjoelnir's post above, however, provides different information: "investigators have not identified any damage to aircraft sensors in relation to crash". This is a different event from the Lion Air crash - shouldn't we keep an open mind in both cases ? EDIT : I clarified my post since discussing two crashes in the same post can be a bit confusing
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Baroque
in service - 2 years
Posts: 3,991
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Post by Baroque on Apr 4, 2019 12:48:56 GMT 1
Hoo boy...FOD has always been Boeing's last line of defense. 787 electrical panel fire, battery fire, engine troubles and now this...
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Post by kevin5345179 on Apr 4, 2019 16:43:37 GMT 1
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Post by stealthmanbob on Apr 11, 2019 12:40:56 GMT 1
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mjoelnir
in service - 2 years
Posts: 4,089
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Post by mjoelnir on Apr 11, 2019 12:58:39 GMT 1
Did not follow procedure, or could not follow procedure? Some still keep up the believe that there was a procedure from Boeing that worked. I think it is already well established, that when you reach: "and now you trim manually with the wheels", that that is not always possible, especially when MCAS has moved the trim quite a bit out off whack and you have high forces on the column. I would call this article a Boeing stroke story, it contradicts several points in the preliminary report, repeats some speculation I read from Boeing friends on A.net and seems to be based on anonymous sources. IMO it is a mystery for me, how Boeing managed to draw this archaic manual trim system through certification after certification, grandfathering after grandfathering, and can point to it as a backup if something goes wrong. Already in the 737-100/200 it was know that this system only worked in some areas of the flight envelope, if you used a pumping action on the elevator while trying to trim. Since that Boeing has increased the force to turn the trim wheels by decreasing the diameter of the hand wheels. There is a reason for the electrical trim motor.
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