I am a man who flies well over 100,000 miles a year in commercial airliners. I have taken many flights in 737 Max 8 planes. I am also a software engineer who spent a significant time of his early career working on servo motor controls and control systems. So I know a think or two about software controlling machinery, overrides, safety stops, redundant sensor input and the like.
I saw an article in the current Time Magazine titled Second-Hand Safety and chose to show you this excerpt:
Enter the 737 Max. Featuring new engines and aerodynamic changes, the grownup Baby Boeing promised carriers up to 20% better fuel efficiency and lower operating costs. There were challenges in the new design. The model’s new LEAP-1B engines, for instance, are 20 in. larger than the original engines. So Boeing redesigned the 737’s pylons, which hold the engines to the wing, and moved them farther forward. But the more powerful engines in a different location could pitch the jet’s nose upward, creating conditions for a midair stall.
To prevent the stall, Boeing created an automated-flight-control feature called the Maneuvering Characteristics Augmentation System (MCAS). When MCAS sensors detected the nose of the plane pitching up, the software controlling the tail’s horizontal stabilizer would automatically push the nose back down. It was a novel fix to a nagging design problem.
But Boeing took a number of steps that blunted the scrutiny the feature could draw from safety regulators at the FAA. In an early report to the FAA that certified the plane as safe to fly, Boeing understated how much the system could move the horizontal tail, according to the Seattle Times. “When the planes later entered service, MCAS was capable of moving the tail more than four times farther than was stated in the initial safety analysis document,” the Times reported. Also, Boeing failed to account for how “the system could reset itself each time a pilot responded, thereby missing the potential impact of the system repeatedly pushing the airplane’s nose downward.” And Boeing said MCAS should not be activated if it received data gathered from just one of two sensors – “and that’s how it was designed” the Times reported.
Just as it understated the extent to which MCAS might take automated control of the plane, Boeing, with the support of regulators, decided against extensive training for pilots on the 737 Max, including in how to disable the software.
— Time Magazine, April 1, 2019, page 44 – Second-Hand Safety
This is scary. When you work on machines that can kill people when they malfunction, it brings the tension and stress to a whole other level. I have a lot of respect for the engineers who are writing the software for the SpaceX Dragon system for manned space flight. I have respect for Elon Musk who will have to watch that first launch with two astronauts on board, whose lives will be at risk. Any one software mistake can result in catastrophic failure.
I do not know the details of the Boeing 737 Max 8 problems, other than what I have read in the popular literature, like all of us. It sounds like the engineers did their jobs. Software will forever control the lives of humans, and the MCAS system is just one of those systems. But not allowing pilots to be trained properly to accelerate sales was negligent. A pilot needs to know that the horizontal stabilizers can act against the flight controls and push the nose down, and pilots need to know how they can disable this if needed. Something went wrong with the software and the pilots apparently weren’t trained to see the failure and certainly they didn’t know how to override the system before catastrophe hit.
This is not good for Boeing.
In this time when “regulations” are being rolled back everywhere, we need to remember that these regulations are there to protect us, from long-term effects of pollution, from longer-term effects of climate change, to very short-term effects of a robot failing and sending an airliner into a nosedive. It is the government’s responsibility to protect us from corporations that have a profit motive above all.
We’re now dealing with the fallout of this lack of enforcement.
I’ll be flying again soon.
2 thoughts on “Boeing 737 Max – Software and Airplanes”
You are a courageous man. You never said ‘no’ to a 737 Max 8 flight, even after the Lions Air crash? I now see those funny ends on the jet wing, the signature of the Max 8, and I say to myself–“stay away from that doomed jet!”
Nah, it has nothing to do with the jet. It’s all software. And, by the way, the winglets are on all jets, not just the 737 max. They are to prevent turbulence at the end of the wing and save 7% on fuel on average. The 737 problem is a software flaw with a poor controls implementation – but then again – I know only as much as I can read in the general press and draw my own conclusion.