Steven Wales
189 people recently died in a tragic crash. The crew and passengers of Lion Air JT610 on board a brand new Boeing 737 MAX 8 never had a chance.
The less than three months old plane had a new software in it. They called it MCAS or Maneuvering Chracteristics Augmentations System. MCAS was a system that didn’t exist in any of the Boeing 737’s before. However, when they built the 737 MAX version, in layman’s term, they built the plane with a larger and more efficient engine.
However, this larger engine, which delivered a further 14% fuel efficiency had to be fitted further forward under the low wings of the 737. This potentially may cause the plane to stall. Stalling is bad. It is basically when a plane stops flying and starts falling.
In order to avoid this, Boeing installed the new MCAS software. This software is designed to tell the plane to move its nose down to increase its speed and avoid it from stalling.
So here comes the problem.
In the computer world, we have this term called GIGO. The old school fella’s will know this. Yes. Garbage In, Garbage Out.
The problem based on the findings so far is this.
On the plane there is a sensor called the Alpha Vane which measures the Angle of Attack (AOA) of the plane. It looks like a small little wing, and they have two of it, one on the pilot side, and the other on the co-pilot’s.
The sensor’s job is to tell the computer the angle the plane is flying at. And if the AOA of the plane is too high, this will result in the plane stalling. Typically the AOA is below 15 to 20 degrees, and the new MCAS software will push the plane’s nose down if it thinks that the AOA is too high.
Now.
With flight JT610, the Alpha Vane sensor measuring the AOA on the Captain’s side was reported to be faulty. So they changed it. That fault was reported from the equally harrowing flight from Bali to Jakarta.
On the fateful final flight, the plane which arrived from Bali the night before, had the sensor changed, and then it took off in the morning.
No one knew what was really wrong with the plane, or about the new MCAS software. No one. Not the maintenance folks, and in fact not even the pilot. He apparently wasn’t trained on it yet.
So they flew the plane.
And once in the air, the faulty sensor told the computer that the plane is stalling. The computer then, without the pilot ever knowing pushed the nose of the plane down further, while the pilot was trying to raise the plane.
In this battle between the pilot and the computer, the computer won. And the pilot, the crew, and the passengers lost and they died. The plane was too low, and the pilot didn’t have enough air to raise the plane and fly it.
The computer literally flew the plane into the ocean.
A few weeks later, Boeing issued an update on the plane, and informed that should the plane have an issue with it’s AOA sensors, one of the way to stop the computer was to switch it off!
Apparently 189 lives could have been saved, had the pilot knew about the software, and flipped a switch to turn it off.
A switch!
A single simple switch was the difference between life and death.
I am still fuming thinking about this. A switch!
Computers are really going to be the end of us all, because while a man makes mistakes, to really, really screw up; you need a computer!
