History of the Boeing 737

To understand why these airplanes crashed, we need to explore the history of the 737.

The original 737 took its first flight in 1967, back when jet fuel was cheap. At the time, people didn’t understand the implications of pollution, so environmental concerns were an afterthought. Most airports were small and rural. They lacked infrastructure, such as jet gates and fancy luggage-loading machinery. In response, airlines asked manufacturers for low-to-the-ground airplanes with easy-to-reach engines, which reduced operating costs. And that’s exactly what Boeing gave the airlines.

The 737 Max’s structure resembles the original 737. The big difference is the engines are larger, the fuselage is bigger, and “winglets” were added to the tip of the wings to improve fuel efficiency.

By all accounts, the 737 fleet has been a smashing success. In 2005, more than 25% of all large commercial airliners were Boeing 737s. However, the recent crashes demonstrate the challenges of modernizing the Boeing 737 fleet.

How did risk aversion cause the crashes?

The (very) basic background story goes like this: The Boeing 737 is a victim of its own success. The airplane thrived for more than half a century during a period when airplanes were safer and more automated. The 737 brand was so trusted that when aircraft upgrades were needed, Boeing re-designed the 737 instead of creating a new fleet of airplanes.

As Stan Sorscher, a former Boeing engineer and a labor representative at the Society for Professional Engineering Employees, said:

“The cost-cutting culture is the opposite of a culture built on productivity, innovation, safety or quality. Boeing’s experience with cost-cutting business culture is apparent." He continues, “… Production problems with the 787, 747-8 and now the 737 Max have cost billions of dollars, put airline customers at risk, and tarnished decades of accumulated goodwill and brand loyalty.”

Sorscher tells a story about producing the Boeing 777 in the 1990s — before the McDonnell Douglas merger — when a Boeing executive was so close to the engineering process he left the plant with grease all over his thousand-dollar suit. The decision to reduce costs and speed up 737 Max production led directly to the crashes. Re-designing an airplane from scratch would take too long, so Boeing built upon the 737’s old and outdated design instead.

More seeds of the 737 Max crashes were sown in 2011 when American Airlines announced their plans to purchase 460 jets from Airbus. Boeing executives were shocked. American Airlines had been an exclusive Boeing customer for more than a decade. At the time of the decision, Boeing planned to build a new jet to replace the aging 737. But after the news, Boeing changed gears. Building a new airplane would cost too much money and take more than a decade to build. To win over American Airlines, Boeing scrapped the new airplane and made a plan to re-engineer the Boeing 737 instead. Thus, the Boeing 737 Max was born.

The Boeing 737 Max had other advantages. Had Boeing released a new aircraft, pilots would have had to train for it by spending time in flight simulators, which would have cost more money. By limiting the changes to the 737, Boeing averted those requirements and saved on expensive pilot training.

Speaking about the project, one Boeing engineer said: “Any designs we created could not drive any new training that required a simulator…That was a first… There was so much opportunity to make big jumps, but the training differences held us back.”

To compete with the Airbus A320-NEO, the Max had larger engines than previous 737 models. They were designed for greater range and fuel efficiency but came with a tradeoff. Since the 737 sits so low to the ground, Boeing had to change the position of the engines on the wing to give the plane ground clearance and account for the extended length of the fuselage.

But by solving an old problem, Boeing created a new one. The new engines were too big to fit in their traditional spot under the wings. To combat the problem, Boeing mounted them forward on the wings. Moving the engine position forward shifted the plane’s center of gravity, which altered the aerodynamics of the aircraft. The position of the new engines pulled the 737 tail down, pushed its nose up, and put it at risk of stalling. (Slow air speed and high nose position are the most common causes of stalls. When an aircraft stalls, it begins to fall because the wings stop creating lift.)

Boeing installed extra software to make the updated 737 fly like traditional ones. It was designed to prevent stalls, compensate for the position of the engine on the wing, and force the aircraft’s nose down automatically when the sensors determined the airplane was flying at a dangerous angle.

The stall-prevention system (known as MCAS) was poorly designed and implemented. Since it was intended to work in the background, Boeing didn’t brief pilots about the software or train them in simulators. The software didn’t activate when the flaps were down or the autopilot was on.³ And when the MCAS system went haywire, pilots could deactivate it with a switch on the center pedestal of the 737 cockpit. As pilots yoked the airplane upwards, the software automatically pushed the aircraft nose back down. This led to the crash of the two Boeing airplanes.