Hacker News Reader

Comment by mdorazio | Hacker News Reader

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.

View on HN

737 Max was a compendium of failures. Airframe wasn’t one of them. If anything, the 737 series’ airframes are perfected to a fault.

Tons of problems that only are accepted due being grandfathered in.

> Tons of problems that only are accepted due being grandfathered in

What are you basing this on?

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.

> a modern EICAS system is required today, and all modern passenger aircraft have one. Except the 737 Max

Instrumentation. Not airframe.

Boeing’s failure was in trying to make a great airframe compensate for failings in other systems.

It is a lackluster airframe but with an entire workforce certified to fly it and thus it is forced to stay around.

Just look at the anti-ice issues preventing 737 Max 7 and 10 to be certified.

> Just look at the anti-ice issues preventing 737 Max 7 and 10 to be certified

Not airframe!

Ignore everything that makes the 737 a modern passenger aircraft and it’s awesome!

> Ignore everything that makes the 737 a modern passenger aircraft and it’s awesome!

You’re moving the goalposts because you didn’t understand what an airframe is.

The engine anti ice system are literally generic aerodynamic parts and control systems provided by Boeing.

You know, part of the same assembly causing MCAS to exist.

But that is of course not part of the airframe.

> that is of course not part of the airframe

Correct.

The 737’s airframe’s excellence is the reason Boeing was loath to let it go. It’s a really good airframe, and a market fit to boot for the transition from hub and spoke. A clean-sheet design for the 737 would look a lot like the 737. That is what makes the shortcuts tempting.

Engines, avionics and control software are distinct components and not part of the airframe. (Debatable only on engine cowlings and mounts. Neither of which were relevant to the 737 Max’s faults.)

Considering the low ground clearance is one of the major issues of the 737 today (which lead to the whole MAX disaster), you'd have to replace the landing gear, and with that you'd also need to make changes to the airframe itself.

> Considering the low ground clearance is one of the major issues of the 737 today (which lead to the whole MAX disaster)

You’re describing an introduced aerodynamic instability. Not an airframe issue. (Misconfiguring the airframe with non-airframe modifications doesn’t count as an airframe failure.)

Analogy: most Linux kernels are not real time. If I run a non-RT Linux in a real-time use case, that doesn’t make the kernel crap. (You probably used it because it’s popular!) It does mean you used it wrong.

737 Max was fundamentally fucked. But it was fucked because it tried to retain a great and proven airframe with incompatible components. The problem isn’t Boeing producing bad airframes. (787 is also a great airframe.) It’s Boeing integrating terribly.

Missing this distinction misses a critical point about the 737 Max’s failure. (It’s also not necessary to understand it the way an aerospace engineer and pilot might. But then don’t misuse, and then double down on misusing, technical terminology.)

You're just clinging to definition while missing the actual issue.

For the 737 to compete with the A320neo, it required much larger engines.

For those engines to fit, they'd either have to raise the landing gear and redesign the airframe to accommodate the changes (which would be a very different airframe), or they'd have to offset the engines (which massively increases the stall risk and lead to the MAX disaster).

This is not an integration issue. There is no possible way for the 737 to fulfill the needs of the 21st century without becoming an entirely different plane.

Didn't the problems start when Boeing began using new engines on an old airframe for the Max?

https://www.eetimes.com/software-wont-fix-boeings-faulty-air...

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.

And putting certain related functionality behind a paywall.

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.

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.

Presumably Boeing weren't under duress when they signed the contract.

The Boeing execs had their bonuses held against their heads.

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)?

There’s a really good podcast episode here:

https://engineered.network/causality/episode-33-737-max/

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:

https://www.seattletimes.com/business/boeing-aerospace/legal...

Southwest and all the legacy carriers

So, how much they spent with the grounding again?

Reply on news.ycombinator.com