Below is the best explanation yet on what caused the two disasters. This is a YouTube video by a pilot with his opinion:
https://www.youtube.com/watch?v=9Ts_AjU89Qk
To summarize:
- Boeing needed to come up with a competitive product to steal back market share from the A321Neo.
- Instead of designing an entirely new plane, which would've cost between $15-30 billion, they retrofit the venerable 737, saving a ton of money.
- The more fuel-efficient engines were much bigger than the previous engines on the 737, and in order to prevent them from scraping against the ground during landing, the engineers had to move the engines more forward and up on the wing.
- This new engine position caused the 737 to fly markedly different, with a propensity to have the nose go up higher more easily
- To offset this different flying dynamic, engineers came up with the MCAS (Maneuvering Characteristics Augmentation System).
- MCAS would step in automatically to trim down a 737 Max whose nose was going to high up on account of the new engine placement
- No pilot training was required for the MCAS, since Boeing didn't want people to know about it.
- The MCAS system communicates with the side angle-of-attack (AoA) vanes to gauge how far up the nose is pointed
- MCAS only needs to read data from one vane. If that vane is malfunctioning, good fucking luck. Amazing no redundancy for this
- When the MCAS kicks in, it spontaneously trims the plane (to angle the nose downwards) while adding more thrust to the engine. It's doing this because it thinks the nose is pointed too high up and the plane could stall
- This is scary for a pilot since the system kicks in instantly w/o warning. There also wasn't training on how to disengage MCAS. So, for both crashes, the pilots are in a full fight with MCAS, with MCAS trying to point the nose down and accelerate the plane, and the pilot trying to do the opposite
- The Ethiopian investigators found the jackscrew (screw responsible for trimming the plane) in the full downward position, indicating that the MCAS thought that there was a stall. It clearly caused the crash.
- Boeing is trying to come up with a software update for MCAS. Mandatory simulation training will be requisite for all 737 Max pilots and the MCAS. Ultimately, the plane is perhaps not property engineered and needs to be fixed mechanically. My guess would be that at least the European aviation authority will ground these planes indefinitely. I don't think a software update with assuage them. Japan will likely react the same.
- The FAA appears to have left oversight with Boeing. Obviously a big conflict of interest. Amazing there were no incidents in the U.S., but it would've happened eventually.
https://www.youtube.com/watch?v=9Ts_AjU89Qk
To summarize:
- Boeing needed to come up with a competitive product to steal back market share from the A321Neo.
- Instead of designing an entirely new plane, which would've cost between $15-30 billion, they retrofit the venerable 737, saving a ton of money.
- The more fuel-efficient engines were much bigger than the previous engines on the 737, and in order to prevent them from scraping against the ground during landing, the engineers had to move the engines more forward and up on the wing.
- This new engine position caused the 737 to fly markedly different, with a propensity to have the nose go up higher more easily
- To offset this different flying dynamic, engineers came up with the MCAS (Maneuvering Characteristics Augmentation System).
- MCAS would step in automatically to trim down a 737 Max whose nose was going to high up on account of the new engine placement
- No pilot training was required for the MCAS, since Boeing didn't want people to know about it.
- The MCAS system communicates with the side angle-of-attack (AoA) vanes to gauge how far up the nose is pointed
- MCAS only needs to read data from one vane. If that vane is malfunctioning, good fucking luck. Amazing no redundancy for this
- When the MCAS kicks in, it spontaneously trims the plane (to angle the nose downwards) while adding more thrust to the engine. It's doing this because it thinks the nose is pointed too high up and the plane could stall
- This is scary for a pilot since the system kicks in instantly w/o warning. There also wasn't training on how to disengage MCAS. So, for both crashes, the pilots are in a full fight with MCAS, with MCAS trying to point the nose down and accelerate the plane, and the pilot trying to do the opposite
- The Ethiopian investigators found the jackscrew (screw responsible for trimming the plane) in the full downward position, indicating that the MCAS thought that there was a stall. It clearly caused the crash.
- Boeing is trying to come up with a software update for MCAS. Mandatory simulation training will be requisite for all 737 Max pilots and the MCAS. Ultimately, the plane is perhaps not property engineered and needs to be fixed mechanically. My guess would be that at least the European aviation authority will ground these planes indefinitely. I don't think a software update with assuage them. Japan will likely react the same.
- The FAA appears to have left oversight with Boeing. Obviously a big conflict of interest. Amazing there were no incidents in the U.S., but it would've happened eventually.