Boeing relied on computers with the same processing power as the SNES. //

Of course, old and slow isn’t always worse: the 737 Next Generation series is the safest narrow-body airplane ever made, in part due to these reliable, if unspectacular, computers. To keep costs down, Boeing wanted to reuse them in the next iteration of the 737 as well. The Max might still be flying today if those computers simply had to perform the same tasks that they had for almost 30 years. //

The important thing to know about the 737 Max is that it was a rush job. In 2010, Boeing’s only rival, Airbus, unveiled the A320neo, a direct competitor to the 737 Next Generation that could fly farther on less fuel and with lower emissions than any other narrow-body airplane. Boeing was caught by surprise: while Airbus had developed the neo in secret, Boeing’s engineers had spent five years debating whether to design a new 737 replacement or simply update the airframe, without resolution. The neo changed that in a matter of months. //

But in order to offer its own new product when the new Airbus came out, Boeing would have to rush the airplane out the door in just five years — less time than it took to develop either the 777 or the 787. The main selling point of the new 737 was clear: new engines that would increase the airplane’s fuel efficiency and range. But to hit that ambitious launch date, Boeing would have to take shortcuts on just about everything else.

The new engines, which were larger and heavier than the ones on the Next Generation, did indeed make the Max just as fuel-efficient as its rival. But they also disrupted the flow of air around the wings and control surfaces of the airplane in a very specific way. During high-angle climbs, this disruption would cause the control columns in the airplane to suddenly go slack, which might cause pilots to lose control of the aircraft during a dangerous maneuver.

Boeing could have fixed this aerodynamic anomaly with a hardware change: “adaptive surfaces” on the engine housing, resculpted wings, or even just adding a “stick pusher” to the controls that would push on the control column mechanically at just the right time. But hardware changes added time, cost, and regulatory scrutiny to the development process. Boeing’s management was clear: avoid changes, avoid regulators, stay on schedule — period. //

Boeing’s software shortcut had a serious problem. Under certain circumstances, it activated erroneously, sending the airplane into an infinite loop of nose-dives. Unless the pilots can, in under four seconds, correctly diagnose the error, throw a specific emergency switch, and start recovery maneuvers, they will lose control of the airplane and crash — //

For comparison, Airbus’ A320neo has computers of similar vintage — but it has seven of them. //