The cost of non quality

The Boeing 737 Max is a legacy plane, built on decades-old systems. Boeing strategy was to keep updating the plane rather than starting from scratch, as this offered cost and competitive advantages: pilots were comfortable flying it, airlines didn’t have to invest new training, design and certification was faster and cheaper.

But this strategy has killed people.

The Max stretched to the limit the old 737 design, creating a patchwork plane without some safety features that are common on other planes.

The Max still has roughly the original layout of the cockpit and the cables/pulleys to control the plane, instead of drive by wire.

The Max by design has an "appropriate enough" level of technology to ensure safety, close to a 90's home computer.

The Max still requires makeshift solutions to keep the plane flying, one of which, an anti-stall system designed to compensate for the larger engines, was central to one of the crash. Let's see why...

Each of the three redesigns of the 737 since the first model in the 60's came (among other minor changes) with a new engine. The plane’s low-slung frame was a benefit for airlines and airports, as workers could load bags by hand and engine maintainance did not require a lift. But this low frame repeatedly complicated efforts to fit, for each plane evolution, bigger (as more efficient) engines under the wing.

To avoid a full redesign, engineers did two things: add a very few inches to the front landing gear and shift the engines farther forward on the wing.

While this solved one problem, it created another: the larger size and new location of the engines gave the Max the tendency to tilt up during certain flight maneuvers. To compensate potentially dangerous angles, engineers created the automated anti-stall system (MCAS), that pushed the jet’s nose down if it was lifting too high.

The software was intended to operate in the background, having the Max flew just like its predecessor, and for this reason the company didn’t even mention the system in its training materials. In addition, the system was designed to rely on a single sensor, instead of two for redundancy.

In the recent crashes, the MCAS malfunctioned and moved a tail flap, tilting the plane toward the ground, but pilots, unaware of why this was happening, tried to combat the system by cutting power to the stabilizer’s motor: the plane crashed.