[sandworm101]

The answer is to stop calling this a 737. Make it a new airframe subject to new type certification. That frees boeing to adopt comprehensive flight controls rather than this layered protections approach. It also means fully training new crews, the avoidance of which was much of the 737-max selling point.

[cmurf]

The FAA doesn't care about the name. They can require a type certificate specifically for the 737 MAX series, separate from the 737 NG series.

And a type certification isn't the only way to require additional training. For sure there are meaningful differences between the 757 and 767, despite sharing the same type certification, and pilots do go through that difference training. There are numerous examples of this.

Where Boeing probably wants to be, is in the vicinity of the regulatory distinction between the A320 and A320neo. It seems really unlikely to me that any 737 NG to 737 MAX transition training burden, is going to approach that of 737 NG to A320neo transition training.

[salawat]

The MAX as it is would not exist if they went that way, as they would then have the freedom to say screw it and ditch all the excess baggage of maintaining the 737 type certificate.

No aerospace engineer worth their salt would have designed the MAX as is given the freedom to reconfigure and avoid all the problematic aerodynamics inherent to the design entirely.

[mchristen]

Changing the name of the plane will not fix the problems in the plane.

The worst part for Boeing is that now under additional scrutiny more problems are being found, that begs the question what else is being missed?

[sandworm101]

Changing the name means a new type cert. It means new a wider scope of design. It means new flight tests, from scratch. It is a very meaningful action.

[msbarnett]

Sure, “changing the name” fixes the problem if you also...change the rest of the airframe.

It’s really not maintaining the type certification that’s the problem, it’s the aerodynamics of the airframe. If they’d called it a 797 from the beginning it would still have needed the MCAS to get FAA approval because the insane aerodynamics mean the stick forces don’t obey the regulations for constant increase in forces approaching a stall. The MCAS isn’t there just so it can pretend to be a 737.

So yeah changing the name is only a solution if by changing the name you mean fundamentally changing every aspect of it.

[sandworm101]

>>> Sure, “changing the name” fixes the problem if you also...change the rest of the airframe. It’s really not maintaining the type certification that’s the problem, it’s the aerodynamics of the airframe.

I don't think you understand the regulatory regime. Changing the name, creating it as a new airframe, means total top-to-bottom re-certification. That means they can ditch all the legacy equipment and start the control system from scratch. Most of the problems with the max atm are related to systems layered atop that legacy equipment (autopilot, control surfaces etc) that cannot be swapped out without changing the type/name.

[msbarnett]

Right but the type certification has nothing to do with why it’s designed the way it is. You seem to think they started with “maintain type certification uber alles” as their goal, when it was actually just a happy consequence of their goal, which was “sell airlines an airframe the same size as current 737s, so they can keep using the same height gates and service vehicles as their vast 737 fleets, but make it much more fuel efficient”

The fucking name isn’t the problem. Trying to work fuel efficiency into too small a package and ending up with something with the stall characteristics of a brick is the problem. Creating it as a “new airframe” fixes the problem only by abandoning the problem they set out to solve, which again, wasn’t “keep the name”.

If this had been the 797 from the getgo, but had tried to put those engines on any airframe that stayed that low to the ground for gate compatibility, they have still needed the MCAS because of the aerodynamics of the necessary engine placement.

Remember that the 737 is such a big seller because it has huge usage on regional routes and in smaller countries. It lands at airports where they still wheel up a set of stairs, or one of those double-decker deplaning buses. The height is a big deal for established infrastructure of customers. If it weren’t, they could have redesigned the landing gear to get the necessary engine clearance instead of fucking up the aerodynamics by moving the engines.

The height, and not the name, is the original sin from which every shitty consequence flows.

[burfog]

They sure could make an MCAS-free 797 low to the ground with those engines. There are lots of ways.

The popular way is with a T-tail and podded engines off the sides of the rear of the body. Boeing has produced such an aircraft. https://en.wikipedia.org/wiki/Boeing_717

Another way is with a high-mounted wing. This is popular for military cargo jets, such as the C-5 and C-17.

Putting engines above the wing is an option. Boeing did it for the YC-14, Antonov did it for the An-72, VFW-Fokker did it for the 614, and Honda did it for the Hondajet.

The landing gear could have be made to stick out extra long for the takeoff and landing, but then partially retract for passenger boarding. During passenger boarding, the aircraft could even sit on the engines.

[raverbashing]

It won't change the problems of the plane, but it will allow Boeing to actually fix them

The problem with the Max is that Boeing favoured the major airlines that wanted 2010s technology in a 60s airframe. But guess what, that doesn't work, in the same way you can't turn a Thunderbird into a Tesla by "just plugging a new engine".

Not that Boeing probably didn't have a vested interest in not investing in a new airframe and preferred the lowest cost project

Now if they can call the Max the 737-2, cut the legacy crap and work around the longitudinal stability by breaking backwards compatibility (and sell the plane at a discount) they could end up with smaller losses

[mchristen]

> The problem with the Max is that Boeing favoured the major airlines that wanted 2010s technology in a 60s airframe. But guess what, that doesn't work, in the same way you can't turn a Thunderbird into a Tesla by "just plugging a new engine".

No, the problem with the plane was that Boeing engineered a crappy solution to a problem they had.

There were 3 major problems that I am aware of.

1) A powerful(flight control wise) automated system that relied on one source of sensor data when multiple are available.

2) The switches that disabled the automated system also disabled all electronic control for the elevator trim, making it much harder for the pilots to recover from an out of trim condition.

3) The normal elevator controls are not enough for the pilot to overcome the out of trim condition so pulling back on the yoke as far as possible would not pitch the plane up enough to regain altitude.

The only way to recover from this type of situation is to momentarily pitch the plane further downwards to take stress off of the elevator trim so the manual controls are easier to operate with your hand. You would have to do that enough times to get the plane back into a stable position, this is not always possible when the plane is already at a low altitude.

[p_l]

Those problems started with Boeing wanting to keep 737NG type rating as a selling point.

Keeping the type rating means that they needed to avoid making completely new wings or significant fuselage changes, which would require a new type rating as well.

All of that led to fitting engines in a way that caused a bunch of aerodynamics problems, which led to crappy solutions.

The economic incentives started it.

[raverbashing]

You're looking at the first why, not at the deeper issues.

Why did they have issues with MCAS? Why did they even need MCAS again?

Because they tried to fit bigger engines onto a 60s airframe that is not fly-by-wire.

If the plane was FBW, no MCAS needed.

If the plane had a bigger ground clearance, no MCAS needed.

> The normal elevator controls are not enough for the pilot to overcome the out of trim condition

I don't think there is a plane where they are, they also move more slowly than the elevators.

[salawat]

This is incorrect. Fly-by-Wire makes minimal difference when the basic aerodynamics are flawed and non-compliant. Airframe certifiability is behavior based. You must meet a prescribed set of behaviors, while lacking any prescriptive misbehaviors. The idea is an airframe in it's minimally "assisted" state should demonstrate basic airworthy characteristics.

A plane should be airworthy even if the majority of it's automation has suffered a casualty.

[raverbashing]

> Fly-by-Wire makes minimal difference when the basic aerodynamics are flawed and non-compliant.

Yes, but you wouldn't need MCAS for maintaining longitudinal stability

> in it's (sic) minimally "assisted" state should demonstrate basic airworthy characteristics.

If that was the case the Max would not be certifiable, MCAS or not

[Aloha]

The 737MAX is airworthy without MCAS, it just flies differently than a 737 NG, hence why they added MCAS.

[weaksauce]

They should be able to override the trim via thumb switch and then cut out the trim system once it’s trammed in. Mcas cuts out when the thumb switch is applied.