But Boeing reduced redundancies, presumably to cut costs. The 737 MAX planes that crashed only had one AoA sensor. Where else did they cut costs? Where else did they reduce redundancies? The public trust has been lost. Boeing needs to design a new plane from scratch, this time let engineers design the plane without interference from accountants.
The fix, amongst other mitigations, was to have the MCAS software cross-check inputs from both AoA sensors.
And yes, I understand perfectly well that this invalidates the idea that the second sensor was "eliminated" to save cost - but if I remember correctly there was a paid option to have the MCAS consider both sensors. So there was a financial aspect to the decision. Someone please correct me if I'm wrong.
The optional feature was essentially networking the two ststems such that the data would be fed to the FCIC for warning light activation, so that pilot's could start running the right checklists.
It's just poor design. If software fails, then any plane should be designed to have a neutral center of gravity in order to give the crew the greatest amount of time to recover from the loss.
[1] https://spectrum.ieee.org/how-the-boeing-737-max-disaster-lo...
It’s almost impossible for a completely fresh design to be safer on day one. There’s so many different ways to fuck up many of them are counterintuitive because nobody ever considers if someone could install this backwards until someone does. 20+ years of debugging written with people’s lives tests just about everything in a way engineers never really think about
With training, improved systems, and redundant sensors, MCAS should be safe. There are other planes that have similar systems. And there procedures for disabling bad sensors or misbehaving sensors.
I'm not sure if MCAS is necessary, there is some indication it is only there to mimic older 737 and plane would be safe without it and with training.
Designers need to make radical changes before cockpit windows would need to be updated. That specific example may not seem like much but there’s a lot of safety critical engineering that goes into such things and yet design flaws where still uncovered.
The original 737-100 was 61,994 lbs empty and the 737-900ER was more than 50% heavier at 98,495 before they started calling them MAX. The 900ER was in many ways a radically different aircraft but got there through a long list of incremental changes leveraging the past.
That’s not to say new designs can’t be quite safe. The much newer A320 family are some of the safest aircraft flying with only 38 hull losses and 1505 fatalities, but do not mistake good design for inevitability.
Side note: I know there isn't a 797 or A390 yet, that was the intent of the statement, a future unknown plane.
On the other hand, no 787 or A380 has ever had a crash or incident that resulted in a passenger fatality or hull loss. This LATAM flight is probably the most serious incident that has ever happened on a 787 in almost 10 years of service, with over 1100 aircraft active.
There have been nearly 10x as many 737s built as 787s and A380s combined. Given the date of first flight (1967 vs. 2009 and 2203, respectively) it is safe to say they have been flown for significantly more than 10x the total flight hours. Probably at least 20x but I’m pulling that number out of thin air.
The data is certainly promising but it’s probably a little too soon to be too confident in relative safety comparisons. For one, we don’t have nearly as much data on those newer airframes as they age.
Lack of QC is why I'll gladly choose any Airbus over any new Boeing.
IIRC, it had two, but each of the computers only used the sensor on its side; which was OK for the original (pre-MAX) design because of they way these sensors were originally used by it.