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Comment by danny8000 | Hacker News Reader

I wonder why Boeing didn’t they design new, longer landing gear instead of moving the engines forward?

Then the engines could have remained in the same position. I am sure most airports could handle a taller airplane.

Not a direct answer, but what you’re more or less asking is “why did they not modernize the 757 instead?” The answer is type ratings. Pilots can fly certain classes of planes based on common training. I.E. the 757 and 767 are common enough you can be trained for both at the same time. The issue with changing geometry of the 737 is you have to then retrain pilots against a new type instead of letting them take an orientation course on the new plane.

Honestly if the accidents did not happen we’d be calling them geniuses. After all, that’s why the 737 is the best selling plane ever.

Not really - they definitely could have extended the landing gear of the 737, as evidenced by the fact that they did exactly that for the 737 MAX 10. To handle the extra length they added telescoping landing gear that are about 10 inches longer than on the other variants

Lengthening the landings gear did nothing to change the engine placement. It was done to allow for type commonality.

https://www.geekwire.com/2018/boeing-737-max-10-landing-gear...

Even with the extension it’s not as tall as the 757 or A320 series.

True, it wasn't done to solve the problem of the engine placement. It solved an entirely different problem. But it does show that the changing the landing gear whilst maintaining type commonality wasn't impossible.

Is there a point where the pilot is expected to remember so many procedures that it’s no longer possible to know all of them? You’d forget something critical here and there.

> Is there a point where the pilot is expected to remember so many procedures that it’s no longer possible to know all of them? You’d forget something critical here and there.

I don't think they have to remember all of them. Pilots rely heavily on checklists to make sure procedures are followed correctly and few mistakes are made.

True. However, there are "memory items" that have to be done from memory when the situation does not allow time for a checklist. Stall recovery is one of them, which is exactly when the MCAS is supposed to activate. I'm pretty sure runaway trim is another since it won't take long to end up in a very bad attitude if this happens, especially at high airspeeds.

There’s just not much time as often cited as the problem when a pilot makes a mistake in a stressful situation, so seems like the add more training mantra ignores a more fundamental issue.

When US Airways Flight 1549 lost both engines, Captain Chesley "Sully" Sullenberger intentionally skipped some items on that checklist. The checklist had been written with the assumption of higher altitude and he didn't have enough time to go through everything.

> Not a direct answer, but what you’re more or less asking is “why did they not modernize the 757 instead?” The answer is type ratings.

But if there's already an existing type out there that's a better fit, why not just use that?

The 757 didn't sell nearly as many planes in total as the 737. There's entire airlines (e.g. Southwest) that only use 737s and have their entire business built around them. The 737 MAX was designed for this use case; a newer 757 might not have sold to these carriers at all.

Plus, the 757 has some features on it that make it more of a longer range, transcontinental jet than the 737. That makes it more expensive. If all you're using it for is regional air service (the existing mission of the 737), then it's too expensive for the job. The 737 is the Honda Civic of the skies; the 757 is more like a (insert more expensive car model here).

Because the plane was basically designed for Southwest Airlines and American Airlines, and they demanded a new 737, not a new plane.

“If I had asked people what they wanted, they would have said faster horses.” -- Henry Ford (purportedly)

There is still a significant niche market for faster horses.

Designing longer landing gear might invalidate the common type rating, as the plane's entire fuselage and wings would be higher off the ground during take-off and landing, which might be non-trivial. Plus it would have different heights compared to previous 737s, which could cause problems with jetways, staircars, maintenance vehicles, luggage ramps, etc.

There's not many things they could've changed about the existing design without it being enough unlike the existing design to effectively count as a new aircraft (logistically if not certification-wise). They could move the engines, but they couldn't change the ground clearance.

The MAX-10 has longer landing gear by 10 inches and I'm assuming it shares the same type rating as the rest of the 737 line. So it is possible.

However the MAX-10 required a telescoping landing gear to achieve that so I'm assuming the real reason to not do so earlier was cost to design, cost to manufacture and weight.

I think the MAX 10 landing gear changes allow for a higher rotation angle (without tailstrike) on takeoff/landing, not actually increasing the engine-ground clearance.

Also the MAX 10 hasn’t been built or certified yet, I’m sure there will be a lot more scrutiny when that does happen.

I think I read that longer landing gear wouldn't fit into the fuselage without major reconfiguration.

The MAX-10 got around that by having a telescoping landing gear and was able to get 10 inches more as a result.

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