R75 Thank you for this article - This expert explains it all - There is an inherent design flaw that causes the nose to pitch up causing them to stall that Boeing will not be able to overcome. It is irresponsible for any airline to be flying these planes. Wow!
It all comes down to business strategy. Chicago-based Boeing is locked in a fierce duopolistic rivalry with Toulouse-based Airbus, with whom it roughly splits the $200 billion airliner market. The biggest segment of that market is for short- to medium-range narrowbody jets that typically carry between 100 and 200 passengers. These are the workhorses of aviation, unglamorous and hard-ridden, endlessly bouncing back and forth on routes like Salt Lake-Denver and La Guardia-O’Hare.
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.
Airbus’ A320 family, meanwhile, took to the skies a generation later, in 1987, but it was a fly-by-wire, composite creature from the get go. In 2014 Airbus rolled out its most recent iteration, the A320neo, a range of jets with engines that were billed as being 15 percent more fuel efficient than the old model.
To maintain its lead, Boeing had to counter Airbus’ move. 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—and it would require airlines to retrain flight crews and maintenance personnel.
Instead, they took the second and more economical route and upgraded the previous iteration. 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. Air France 447 was lost in 2009 after pilots overreacted to minor malfunctions and became confused about what to expect from the autopilot.
