U.S. FAA proposes requiring key Boeing 737 MAX design changes • Hacker News Board

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#31

Post by jonathanliu » Mon, Aug 03, 2020, 8:56 PM UTC

Nacdor wrote: post #6

Given the option, would anyone choose to book a trip on one of these new Boeing aircraft rather than anything else? I know I wouldn't, my family wouldn't, and none of the friends or co-workers I've discussed this with would. Something tells me airlines are going to be making it even more difficult to determine which aircraft you'll be flying on when you book a ticket. As far as I know they're not required to tell you…

Even the non-MAX 737s have had issues recently.

https://www.usatoday.com/story/travel/airline-news/2020/07/2...

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#32

Post by beamatronic » Mon, Aug 03, 2020, 8:56 PM UTC

Nacdor wrote: post #6

Given the option, would anyone choose to book a trip on one of these new Boeing aircraft rather than anything else? I know I wouldn't, my family wouldn't, and none of the friends or co-workers I've discussed this with would. Something tells me airlines are going to be making it even more difficult to determine which aircraft you'll be flying on when you book a ticket. As far as I know they're not required to tell you…

Watch them rename it the Boeing American Patriot

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#33

Post by jacquesm » Mon, Aug 03, 2020, 8:56 PM UTC

Nacdor wrote: post #16

Forgeties79 wrote: post #14

Earlier quoted context omitted.

Didn’t an email link with Boeing employees basically saying the exact same thing? “I’d never let my family fly on one” or something?

Looks like it: https://www.businessinsider.com/boeing-employees-wouldnt-let... > 8 months before the first 737 Max crash, 2 Boeing employees talked about how they wouldn't let their families fly on the plane

There is a funny anecdote, likely apocryphal, but still worth retelling because of the implied wisdom:

When talking about the soon to be released Chinese passenger jet one of the principals of the company was overheard saying that he would never allow his family to board one of these aircraft, that's how bad they were.

Some party bigwig overheard this and addressed the man: "I know 100% certain that this is going to be one of the best aircraft ever made in China. Because you and all your extended family will be on board the maiden flight."

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#34

Post by jmann99999 » Mon, Aug 03, 2020, 8:56 PM UTC

Given the upcoming Microsoft Flight Simulator 2020 release, I wish it could provide us non-commercial flyers with a simulation of the flight controls under the specific events that cause failure in the Max 737.

I realize the subject isn't something a corporation would touch or code for, nor do they have a 737 in the lineup for 2020, but it would provide me with better understanding of the problem.

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#35

Post by [deleted] » Mon, Aug 03, 2020, 8:56 PM UTC

Nacdor wrote: post #6

Given the option, would anyone choose to book a trip on one of these new Boeing aircraft rather than anything else? I know I wouldn't, my family wouldn't, and none of the friends or co-workers I've discussed this with would. Something tells me airlines are going to be making it even more difficult to determine which aircraft you'll be flying on when you book a ticket. As far as I know they're not required to tell you…

[deleted]

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#36

Post by linuxftw » Mon, Aug 03, 2020, 8:57 PM UTC

rootusrootus wrote: post #18

onde2rock wrote: post #10

Hum, it doesn't seem like a lot. Maybe I missing something, but looks like a software update to make MCAS more robust. And if it bug, raise an alarm and flight-crew operating procedures should be (?) to deactivate MCAS and fly without ? Could pilots actually fly the plane without MCAS ? It must feels like an entirely different aircraft.

> It must feels like an entirely different aircraft No, if MCAS is disabled then the vast majority of the time it will fly just like normal. MCAS is only there to adjust flying characteristics when the wing is at a high angle of attack.

> only there to adjust flying characteristics when the wing is at a high angle of attack.

No, that's a Boeing talking point. It's there to prevent the aircraft from stalling, not to 'adjust flying characteristics.' The nose pitches up during high thrust, MCAS kicks in to to counter what the pilot is doing (stick and thrust) so the plane doesn't stall.

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#37

Post by Spartan-S63 » Mon, Aug 03, 2020, 8:57 PM UTC

henryfjordan wrote: post #7

zaroth wrote: post #3

https://www.faa.gov/news/media/attachments/19_035n-R3-8-3-20... > "To address the unsafe condition, the FAA proposes to require four design changes: (1) installing updated flight control software (with new control laws) for the FCC operational program software (OPS), (2) installing updated MDS display processing computer (DPC) software to generate an AOA disagree alert, (3) revising certain AFM flightcrew operating p…

> disable MCAS for the remainder of the flight. My understanding is that the MCAS or something equivalent is necessary on the 737 MAX because the engines sit lower than they really should and the forward propulsion creates torque that raises the nose of the plane. Something needs to counteract that force. If the MCAS is disabled, is the pilot able to trim the airplane manually similar to how MCAS works? Or will they…

I don't know the specifics, but if MCAS is disabled, I'd assume the pilots would be able to manually trim the plane. In fact, one of the early flaws, IIRC, of MCAS was that it was tied to electric trim, meaning that to disable MCAS you also had to disable electric trim and and thereby go to manual. Since the 737 stabilizer trim is connected via wires and not fly-by-wire controls, the plane can get into an aerodynamic position where a pilot physically cannot bring the plane back into trim.

Boeing has a maneuver to correct this, but it involves descending to reduce aerodynamic forces on the stabilizer, adjusting trim, regaining altitude, and rinse and repeat until you're back in trim.

Personally, I wouldn't want to be a passenger on a 737 without electric trim and go through that maneuver, but it's better than crashing. Basically, the 737 should be considered too old an airframe to allow for non-type-rating-changing modifications (i.e. fly-by-wire stab trim, etc).

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#38

Post by onde2rock » Mon, Aug 03, 2020, 8:57 PM UTC

zaroth wrote: post #3

https://www.faa.gov/news/media/attachments/19_035n-R3-8-3-20... > "To address the unsafe condition, the FAA proposes to require four design changes: (1) installing updated flight control software (with new control laws) for the FCC operational program software (OPS), (2) installing updated MDS display processing computer (DPC) software to generate an AOA disagree alert, (3) revising certain AFM flightcrew operating p…

Wow the report is very interesting ! In the paragraph about the mandatory AOA DISAGREE alert :

> Some 737 MAX airplanes were delivered without this alert feature, by error.

The FAA is useless ...

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#39

Post by hashmymustache » Mon, Aug 03, 2020, 8:58 PM UTC

duck wrote: post #26

Nacdor wrote: post #16

Earlier quoted context omitted.

Looks like it: https://www.businessinsider.com/boeing-employees-wouldnt-let... > 8 months before the first 737 Max crash, 2 Boeing employees talked about how they wouldn't let their families fly on the plane

I would imagine with a company of the size of Boeing you could find a larger group of folks that wouldn't allow their families to fly in any airplane.

Sure but there’s a big difference between not wanting someone in your family to have surgery and not wanting them to go to a specific surgeon.

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#40

Post by jacquesm » Mon, Aug 03, 2020, 8:58 PM UTC

karmelapple wrote: post #24

henryfjordan wrote: post #7

Earlier quoted context omitted.

> disable MCAS for the remainder of the flight. My understanding is that the MCAS or something equivalent is necessary on the 737 MAX because the engines sit lower than they really should and the forward propulsion creates torque that raises the nose of the plane. Something needs to counteract that force. If the MCAS is disabled, is the pilot able to trim the airplane manually similar to how MCAS works? Or will they…

This might be oversimplification, but I'll venture it and hope someone corrects me if I'm wrong: If MCAS is disabled, then the airplane will fly very differently from the 737s that everyone with an existing 737 flight rating is used to. So the plane can fly, but it'll feel different. And that sure does seem like a problem to get back safely to the ground.

But not as big a problem as having MCAS misbehaving, hence the change.