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kingdragonfly: If Boeing installed three AoA sensors, then the plane would have needed to be re-certified.
So the executives took the quick and easy solution, instead of taking the long view to improved safety.
And neither the B737NG nor the B737MAX are certifiable against current certification requirements: Boeing relies on "grandfathering" rights that go back to the original B737-100 certification (on 21st December 1967).
A major change such as a re-architecture of the flight control systems might induce at least some certification authorities to actively reconsider whether the grandfathering criteria still apply.
And that would be catastrophic for Boeing
Technofreak:
...
Boeing should have been more upfront about the inclusion of the MCAS, there's no doubt about that. However in my opinion if the crew had used standard procedures for AoA miscompare alerts and electric trim problems they should have been able to handle the MCAS failures.
I thought the AoA miscompare alert was an extra-cost option that wasn't present on the aircraft in question?
People hear what they see. - Doris Day
DonH:
Technofreak:
...
Boeing should have been more upfront about the inclusion of the MCAS, there's no doubt about that. However in my opinion if the crew had used standard procedures for AoA miscompare alerts and electric trim problems they should have been able to handle the MCAS failures.
I thought the AoA miscompare alert was an extra-cost option that wasn't present on the aircraft in question?
You may be right. I was a bit generic with my use of the term AoA miscompare alerts. I was considering an inadvertent operation of the sticker shaker when the indicated airspeed was above stalling speed as one form of miscompare alert, (something which I understand can/will happen with a faulty AoA output). It did happen in both crash flights.
On at least one of the flights in question there was mention on the CVR of unreliable airspeed readings which I understand was a reference to the stick shaker operating while the indicated airspeed was well above the stalling speed. I understand the correct procedure in this scenario is to set a certain power setting and nose attitude, the combination of which will always give a safe airspeed, (not too slow and not too fast) this was never done.
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DonH:
I thought the AoA miscompare alert was an extra-cost option that wasn't present on the aircraft in question?
It wasn't supposed to be, but it actually was, because according to Boeing it "was tied or linked into the angle of attack indicator, which is an optional feature on the MAX".
South West Airlines, the largest MAX operator, said "the airplane maker’s documentation incorrectly claimed that its aircraft had operable angle-of-attack disagree warning lights. But Boeing informed Southwest that the AoA function was actually inoperative only after the Lion Air crash in Indonesia last October."
From http://flash.avweb.com/eletter/4324-full.html?ET=avweb:e4324:2450082a:&st=email#232723: Boeing said "the disagree alert was not operable on all airplanes because the feature was not activated as intended.The disagree alert was tied or linked into the angle of attack indicator, which is an optional feature on the MAX. Unless an airline opted for the angle of attack indicator, the disagree alert was not operable."
Edit: include attribution
Interesting YT video as to why Boeing built the 737 Max rather than a completely new plane.
Regards,
Old3eyes
old3eyes:Interesting YT video as to why Boeing built the 737 Max rather than a completely new plane.
So Boeing released a new (old) plane that is more likely to stall mid air than the variant it replaced?! No worries, they threw in some software to correct this increased risk of stall. Problem is, the software didn't quite work as intended and contributed to, not one, but two, fatal air crashes. But, hey, not to worry, there's revised software on the horizon to correct the higher stall risk again; second time lucky.
Pass. I'm not boarding a 737 Max if I can avoid it.
dafman:old3eyes:So Boeing released a new (old) plane that is more likely to stall mid air than the variant it replaced?! No worries, they threw in some software to correct this increased risk of stall. Problem is, the software didn't quite work as intended and contributed to, not one, but two, fatal air crashes. But, hey, not to worry, there's revised software on the horizon to correct the higher stall risk again; second time lucky. Pass. I'm not boarding a 737 Max if I can avoid it.
Interesting YT video as to why Boeing built the 737 Max rather than a completely new plane.
https://www.youtube.com/watch?v=BfNEOfEGe3I
I fully agree. Its badly designed, so they use software to stabilise it???? They could use ballast but that would cost fuel money, so better to take the safety risk instead. Poor.
tdgeek:
dafman:old3eyes:So Boeing released a new (old) plane that is more likely to stall mid air than the variant it replaced?! No worries, they threw in some software to correct this increased risk of stall. Problem is, the software didn't quite work as intended and contributed to, not one, but two, fatal air crashes. But, hey, not to worry, there's revised software on the horizon to correct the higher stall risk again; second time lucky. Pass. I'm not boarding a 737 Max if I can avoid it.
Interesting YT video as to why Boeing built the 737 Max rather than a completely new plane.
https://www.youtube.com/watch?v=BfNEOfEGe3I
I fully agree. Its badly designed, so they use software to stabilise it???? They could use ballast but that would cost fuel money, so better to take the safety risk instead. Poor.
I'm not sure how you think you could use ballast to stabilise a plane - it's not a ship!
The plane itself is not unstable. It did however have a tendency to pitch up with an elevated angle of attack which MCAS was their to smooth out.
Fewer checked bags means more sandbags in the cargo hold
Next time the pilot makes an announcement that you're being delayed at the gate while a few extra bags are loaded below, consider what might be being hoisted into the cargo holds instead. Adding sandbags to correct weight and balance in an airplane by providing ballast and redistributing weight has long been a common practice in the airline industry. But ever since the new checked bag fees were introduced on many airlines, with fewer passengers checking bags as a result, there's been an upturn in the need to add ballast before takeoff, particularly on smaller commuter flights that are more sensitive to weight issues.
"The weight balance of the aircraft is set up to where they're usually expecting a certain amount of bags to balance out the plane," explains the captain for a major U.S. airline. "So if we have 50 passengers on board, we expect 50 bags and that offsets the weight of the passengers and balances out the aircraft to give it the right center of gravity for take off.
"But what happens now, with charging so much for bags, is that people carry on so there's a weight balance problem. Because of that we end up carrying sometimes 500 or 600 pounds of sand bags to even us out."
kingdragonfly: Actually planes do use ballast, both permanent and temporary.
https://www.aol.com/2010/08/20/five-things-airlines-dont-want-you-to-know/
I'm fully aware of loadings on a plane and pax / weight distribution- it's an every day reality of many flights I fly on (ATR and Q300 often need passengers to move for weight & balance if there are light loading and not many bags).
My point was that that adding "ballast" would not fix the MAX issue as it's not the cause of the problem.
dafman:
sbiddle:
dafman:
sbiddle:
To me that's a lot scarier than a 737 MAX doing exactly what it should be doing, and pilots failing to fly it correctly.
I said earlier I was bowing out of this discussion, but you remind of Trump trumpeting "no collusion, no obstruction", whereas the facts plainly state the opposite.
The official review concluded that the pilots of the Ethiopian flight correctly followed Boeing emergency procedures.
I'll trust the official findings over a member of the public independently dreaming up their own theories as to the crash cause.
The official report is not out, merely a summary of it. That summary very clearly shows the pilots failed at the aviate part of "aviate, navigate, communicate".
They flew a plane significantly overspeed and made no attempts to resolve that issue. That is not a case of following emergency procedures to the tee, and is certainly not a case of following Boeing MCAS procedures by reenabling MCAS after failing to regain control.
Ok, I'll bow out now until the formal report is published. Nothing I have read from numerous credible news agencies aligns with what you and Technofreak assert. The media is clear that initial findings are that the pilots correctly followed Boeing's procedures; the clear implication for fault sitting firmly with Boeing.
Even the Boeing CEO is now saying the pilots "did not completely follow safety procedures".
“We’ve arranged a society based on science and technology, in which nobody understands anything about science technology. Carl Sagan 1996
old3eyes:Interesting YT video as to why Boeing built the 737 Max rather than a completely new plane.
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