#737 MAX FLIGHT CONTROL SYSTEM SOFTWARE#

The solution was to extend the engine up and well in front of the wing. That's a centerline difference of well over 30 cm (a foot), and you couldn't вЂњovalize' the intake enough to hang the new engines beneath the wing without scraping the ground. The engines on the original 737 had a fan diameter (that of the intake blades on the engine) of just 100 centimeters (40 inches) those planned for the 737 Max have 176 cm. With the 737 Max, the situation became critical. One of the most noticeable to the public was changing the shape of the engine intakes from circular to oval, the better to clear the ground.

#737 MAX FLIGHT CONTROL SYSTEM SOFTWARE#

Various hacks (as we would call them in the software industry) were developed. As the 737 grew and was fitted with bigger engines, the clearance between the engines and the ground started to get a littleвЂ¦um, tight.Д«y substituting a larger engine, Boeing changed the intrinsic aerodynamic nature of the 737 airliner. There was just one little problem: The original 737 had (by today's standards) tiny little engines, which easily cleared the ground beneath the wings.

And that's why Boeing wanted to put the huge CFM International LEAP engine in its latest version of the 737. That's whymarine diesel engines stand three stories tall. Lycoming O-360 engine in my Cessna has pistons the size of dinner plates. The most effective way to make an engine use less fuelper unit of power produced is to make it larger. That's as true for jet engines as it is for chainsaw engines. The principle ofД¬arnot efficiency dictates that the larger and hotter you can make any heat engine, the more efficient it becomes. Much had to do with the engines themselves. Seat-mile costs'-the cost of flying a seat from one point to another. They work as allies to relentlessly drive down what the industry calls вЂњ Most of those market and technical forces are on the side of economics, not safety.

Airliners constitute enormous capital investments both for the industries that make them and the customers who buy them, and they all go through a similar growth process. This is not, by any means, unique to the 737. Over the years, market and technological forces pushed the 737 into ever-larger versions with increasing electronic and mechanical complexity. Not to mention the fact that it could be flown by a two-person cockpit crew-as opposed to the three or four of previous airliners-which made it a significant cost saver. Airlines (Д®specially Southwest) loved it because of its simplicity, reliability, and flexibility. Back then it was a smallish aircraft with smallish engines and relatively simple systems. The 737 first appeared in 1967, when I was 3 years old. Though airliner passenger death rates have fallen over the decades, that achievement is no reason for complacency. In an industry that relies more than anything on the appearance of total control, total safety, these two crashes pose as close to an existential risk as you can get. Now it's time for me to write about both together.Д«een in the news because of two crashes, practically back to back and involving brand new airplanes. I have written extensively about both aviation and software engineering. I have been a pilot for 30 years, a software developer for more than 40. The views expressed here are solely those of the author and do not represent positions of IEEE Spectrum or the IEEE.

737 max flight control system