Very interesting article re: 737 MaxThis article points out a design flaw in the 737 Max and infers the compromises are a contributing factor in the crashes. From Fliegerfaust - I will try for the link. %)NowRetired
Boeing’s entry, the 737, first flew in 1967, and though various improvements have been rolled out over the years, at heart it’s still a creature of the Right Stuff era. Instead of computer-controlled fly-by-wire controls, which guide a plane’s flight electronically, it still has old-fashioned mechanical actuators, and it’s made of aluminum rather than modern lightweight composites.
Boeing had to counter Airbus’. It had two options: either clear off the drafting tables and start working on a clean-sheet design, or keep the legacy 737 and polish it. The former would cost a vast amount—its last brand-new design, the 787, cost $32 billion to develop—
Instead, it took the second and more economical route and Boeing swapped out the engines for new models, which, together with airframe tweaks, promised a 20 percent increase in fuel efficiency. In order to accommodate the engine’s larger diameter, Boeing engineers had to move the point where the plane attaches to the wing. This, in turn, affected the way the plane handled. Most alarmingly, it left the plane with a tendency to pitch up, which could result in a dangerous aerodynamic stall. To prevent this, Boeing added a new autopilot system that would pitch the nose down if it looked like it was getting too high. According to a preliminary report, it was this system that apparently led to the Lion Air crash.
If Boeing had designed a new plane from scratch, it wouldn’t have had to resort to this kind of kludge. It could have designed the airframe for the engines so that the pitch-up tendency did not exist. As it was, its engineers used automation to paper over the aircraft’s flaws. Automated systems can go a long way toward preventing the sorts of accidents that arise from human fecklessness or inattention, but they inherently add to a system’s complexity. When they go wrong, they can act in ways that are surprising to an unprepared pilot. That can be dangerous, especially in high-stress, novel situations.