737 MAX. That whole saga was because of Boeing trying really hard to not certify a new airframe so that they could quickly push out a competitor to A320 Neo. The result was hundreds of deaths.
Yes. The problem wasn’t the airframe, nor even frankly the engines, it was the combination plus the decision to fix an aerodynamic instability with an undocumented software patch.
That last part is key: the MCAS system was designed to fake handling like the older planes but they skimped on safety to save the cost of a second sensor and didn’t train pilots on it or have an override mechanism. If the whole thing had been aboveboard they’d have saved so many lives…
There was an override system, MCAS drove the stabiliser trim motors and so flipping the stabiliser trim motor cutout switches would disable MCAS. This relied on the pilots diagnosing an MCAS runaway as a stabiliser trim runaway and enacting the same checklist.
However, to add insult to injury, the MAX also had another change. In the 737 NG, there were two switches, one would disable automated movement of stabiliser trim, the other would cutout the electric trim motors entirely. This allowed the pilots to disable automation without losing the ability to trim the aircraft using the switches on the yoke.
The MAX changed this arrangement, now either switch would cut power to electric trim. Tragically the pilots of Ethiopian Airlines Flight 302 recognised the runaway, enacted the correct checklist, but the aircraft was now so far out of trim that aerodynamic loads made correcting the situation using the hand trim crank impossible. In desperation the pilots restored electrical power to the trim motors, MCAS re-engaged and drove the aircraft into the ground.
For example a modern EICAS system is required today, and all modern passenger aircraft have one. Except the 737 Max.
The 737 Max 7 and 10 had to get a waiver due to not being certified in time by the hard requirement to have one when updating old types. Let alone certifying new types.
Southwest's 737 MAX contract had a penalty clause of $1 million per aircraft that would trigger if Boeing's delivery contract for the 737 MAX failed to meet certain standards, particularly Southwest's insistence that no flight simulator training be required for the MAX
Meaning, the roots of the “no new type rating” requirement come from Southwest, not Boeing.
This is an interesting detail I had not heard. Can you link to a backstory on this? Why would such a contract ever be signed (especially for a technological product)?
Basically they were looking for an edge against Airbus and a really big one was being able to promise that pilots wouldn’t need a separate certification from the existing 737, which is where that MCAS software came in trying to make the new hardware behave like the existing planes. The allegations about Southwest in particular got the most attention in this lawsuit: