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Comment by djcapelis | Hacker News Reader

> The A320neo and A320 have a common type rating too.

> Googling seems to suggest the differences are fairly minor however.

> I guess Airbus benefits in the A320 being a newer airframe than the 737 (which is ~50 years old now)?

The 737 is uniquely low to the ground among modern aircraft. (This was an advantage at airports without jetways high off the ground a long time ago.) Which means for every other model there’s plenty of space for new larger style engines under almost all of the existing planes. This makes airbus’s neo programs comparatively simple and reasonable for keeping the same type rating. The 737 doesn’t have the space, so they moved the engine location and came up with the MCAS as a workaround. It was clever, but unfortunately, too clever.

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The truth of the matter is that the 737classic update from 1984 was already too low on the ground for the CFM56 engines to fit. So they had to reshape the nacelles into that odd shark mouth looking oval shape unique to 737s for that little extra bit of ground clearance. The problem isn’t new, was well known and yet greed made them update that same old airframe for 35 more years until it all came crashing down (literally, sadly)

Greed? The 737 is an excellent airframe. Suggesting that they kept the old airframe around because of greed is just silly.

Question: At what point does maintaining the 737 type rating become too much "technical debt"? Why not create a new (modern) type that fills the same commercial requirements as the 737?

I wish the FAA would grow some balls and come right out and declare the old 737 type rating as deprecated. No new designs (including the 737 MAX) are allowed to fall under it. The type is many decades outdated and increasingly poor decisions are being made to conform to it.

Call your members of Congress and demand this.

I'm wondering how other certification agencies will react.

Specifically after more and more of the incestuous relationship between the FAA and Boeing comes to light.

Including claims that experienced engineers, which were in charge for certain certifications were demoted or fired if they were too critical or outright refused to certify certain sub systems as was reported in the Seattle Times[1]

It seems that since 2004 engineers in charge of certification were stopped to communicate directly with techies at the FAA, but reported to their managers, which in turn communicated with the FAA.

He who pays the piper calls the tune.

[1] https://www.seattletimes.com/business/boeing-aerospace/engin...

It seems we unfortunately found the answer to that question empirically.

Boeing was considering that. But were caught completely off-guard by the announcement of Airbus' 320NEO.

American Airlines (a life long Boeing customer) placing a massive order of 320NEO put Boeing into full throttle panic mode and triggered the unfortunate decision to apply yet a number of hacks to an airframe, which was not suitable for the purpose.

> Question: At what point does maintaining the 737 type rating become too much "technical debt"?

I was about to snark, "Sometime prior to people dying as a result of the debt."

But then I considered that (potentially) the $X dollars saved by allowing the technical debt to live on, could probably be invested in some other way that saves far more lives. I.e., obesity reduction, smoking cessation programs, etc. So perhaps the issue isn't that simple.

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