Originally Posted by
BenA
The wiring issue is the most impactful. Basically, from things we've learned from accidents over the last few decades, there are new rules about how wires can be routed through an aircraft that the 737 design doesn't meet.
https://www.seattletimes.com/busines...boeing-missed/
The concern here is that ripping out wiring and replacing it in an already-built airplane may cause more risk than leaving it the way it is. Basically nobody has an appetite for changing the 737NG based on the new rules, and Boeing's argument is that they shouldn't have to go change already built 737MAX aircraft, either, for the same reason.
They'll almost certainly make changes for future production going forward regardless, but the question is what to do about the frames that already exist. Not a cut and dry "correct" or "incorrect" situation, just a classic engineering risk tradeoff that the FAA has to work through and make a decision on.
This article has a nice rough summary of all the areas being focused on, but I'm sure there are other small things happening internally at Boeing that don't make the newspapers...
https://www.barrons.com/articles/the...ng-51580752481
This is not a new strategy... there are many things in airliner design evolution of production versions that do not make the newspapers... critical ones sometimes. Speaking of the DC-10 the floor venting system was redesigned and changes implemented following a certain frame number of the -10 series. I cannot remember exactly the frame number, it has been a long time since I read the Subcommittee Investigation report into the AA191 accident. Anyway all DC10-30 series CF6 powered and -40 series JT9 powered frames were delivered with the significantly improved venting system which was designed to vent faster and reduce pressure delta in the event of sudden depressurization such as inflight cargo door failure, therefore avoid floor beam collapse - beams contained control cable runs that were implicated in the loss of control in the 1972 AA and 1974 THY events. The AA191 disaster was not a direct result of airframe design deficiency, as was clarified by another poster above. By the end of its service life the DC-10 had restored a good reputation. I flew on these planes many times with different airlines VARIG BCal NW KL and others. I did not worry about the basic design.
Previous Douglas commercial airframes had a very good reputation in the industry for robustness and longevity and the -10 also followed in these ways. Some other airliners would not be converted to freighters with the same zeal because of airframe fatigue limits and nontransparent strength concerns.
The MAX has other problems including a lack of basic aerodynamic stability within important segments of normal flight envelope and it would not be certificated without dubious automatic systems including the nightmare MCAS. The DC-10 did not have such basic problems, at least not before the MD-11 "enhancement."
I do not want to think of commander struggling against uncommanded pitchdown MCAS Kubrick was right so many years ago... claro! This system should be called HAL "I'm sorry Dave I can't let you do that..." It is time to unplug HAL!
If somehow I could have direct choice today, with only MAX or DC-10, then I pick DC-10 every time...