737 Max cleared to fly again

FlyingTiger said:
I suggest you read about the development of the MAX and why the system was required by the FAA to get it's Airworthiness Certificate.
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Do you understand the difference between reduced stability and instability? Are you familiar with CFR14 25.173?

Nauga,
and Cooper and Harper
 
nauga said:
I don't think it's political, I think it's based on what's top-of-page in recent news and a shiny lure for flawed "analysis."

Nauga,
and some good old fashioned blamestorming
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It wasn't political from all the other countries like China that immediately went into overdrive to destroy Boeing?
 
Look, I think Boeing made mistake and I don't necessarily like or love Boing, but I just don't think it's significantly worse than a number of other crash situations... and destroying not only Boeing, but a number of other industries (like the apparent insurance losses driving the GA spike) through economic, political, and media warfare doesn't get a free pass in my book.
 
RyanShort1 said:
It wasn't political from all the other countries like China that immediately went into overdrive to destroy Boeing?
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You got me there, I was thinking only of the armchair analysis here and elsewhere. It swings the other way too, one only has to look back at AF447 and the condemnation of Airbus' control strategy to see the other side. The astute observer will note who does *not* rush to judge in these cases.

Nauga,
and a bit of discretion
 
nauga said:
It swings the other way too, one only has to look back at AF447 and the condemnation of Airbus' control strategy to see the other side. The astute observer will note who does *not* rush to judge in these cases.
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Wisdom. I just think people need to be more objective to the big picture.
 
nauga said:
Do you understand the difference between reduced stability and instability? Are you familiar with CFR14 25.173?

Nauga,
and Cooper and Harper
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So we can agree that the Boeing Max as designed without MCAS failed to meet the stability requirements of CFR14 25.173
 
FlyingTiger said:
So we can agree that the Boeing Max as designed without MCAS failed to meet the stability requirements of CFR14 25.173
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Which requirement(s) are you looking for agreement on? I suggest you read the FAA's return to service report, it's very clear. Specifically, "...FAA regulations-specifically 14 CFR 25.143, 25.201, 25.203, 25.251, and 25.255-still require the control column to have a higher pull-force feel in these flight regimes than would exist on the 737 MAX without the added stability from the STS and MCAS function."

There is no mention of instability.

Nauga,
carpe data
 
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RyanShort1 said:
Look, I think Boeing made mistake and I don't necessarily like or love Boing, but I just don't think it's significantly worse than a number of other crash situations... and destroying not only Boeing, but a number of other industries (like the apparent insurance losses driving the GA spike) through economic, political, and media warfare doesn't get a free pass in my book.
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I don't believe it was a single mistake considering the issues with the tankers (leaving junk in the tanks) and the Starliner (software). Boeing has lost a lot of goodwill. I see it not as a single mistake, but a corporate culture that allows shoddy work. This MCAS issue is fixed, is there another problem in an unrelated system?
RyanShort1 said:
It wasn't political from all the other countries like China that immediately went into overdrive to destroy Boeing?
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So was China wrong in grounding the plane? And the other countries? While there probably was some degree of politics, it's hard to say how much, in a situation like this. I find it hard to blame them for grounding the plane.
 
nauga said:
Which requirement(s) are you looking for agreement on? I suggest you read the FAA's return to service report, it's very clear. Specifically, "...FAA regulations-specifically 14 CFR 25.143, 25.201, 25.203, 25.251, and 25.255-still require the control column to have a higher pull-force feel in these flight regimes than would exist on the 737 MAX without the added stability from the STS and MCAS function."

There is no mention of instability.

Nauga,
carpe data
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So we can agree that the Boeing Max as designed without MCAS failed to meet the stability requirements of CFR14 25.173 (c)
 
FlyingTiger said:
Really, so MCAS serves no real purpose in stabilizing the aircraft? Then what does it do; why does it exist? I
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Yes. There are a number of technical papers on the MCAS that go into more detail but as designed the MCAS would come online only at extreme vertical AoA at the edge of the control envelope, i.e., at a place where a passenger jet does not fly in normal operations. Due to the forward mounted engines the aircraft, at those extreme nose up attitudes, had a tendency to go from airplane mode into rocket mode which would reduce the pilot control stick forces. The Part 25 regulation states those control forces must remain linear throughout the flight envelope. Enter the MCAS to increase those control forces. It has zero input in normal operations except when it breaks.
 
FlyingTiger said:
So we can agree that the Boeing Max as designed without MCAS failed to meet the stability requirements of CFR14 25.173 (c)
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Again, from the FAA's return to service report, "Without the MCAS function, in some small areas of the flight envelope—such as approaching a stall and during higher g-force maneuvering—the new engines contribute to the control column feeling lighter in the 737 MAX than the regulations allow."

You really should read the report.

Nauga,
with bobweights and downsprings
 
WDD said:
I don’t have an issue with computer assisted control. It gives me pause to think of computer assisted control to overcome an inherent instability brought in by bad design.
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Reading this, I'm not sure you understand why MCAS was needed in the MAX.

The airplane is not unstable in any part of the envelope. MCAS is used to address a certification requirement regarding pitch forces at increasingly higher angles-of-attack. The conditions during which MCAS would activate on not in the normal flight envelope of the airplane and, even then, the airplane isn't unstable.

At very high AoAs, the larger nacelles, mounted father forward from the CG, produce a nose-up pitching moment which cancels out some of the natural increase in pitch-down moment as the AoA progressively increases. MCAS counters this by introducing a nose-down bias through the introduction a nose-down stabilizer trim.

Having augmentation systems that operate at the extreme edges of the envelope are common on transport aircraft. I've flown two different airliners that have stick-pushers. In those airplanes the stall characteristics are sufficiently poor that stick-pushers, which move the yoke forward with such force that the pilot's can not overcome or prevent it. The DC9/MD80/B717 all have unpowered elevators, for normal flight situations, but a powered elevator actuator that aggressively pushed the elevators toward nose-down in situations were the airflow over the stabilizer and elevators is blanked by the wing making a stall recovery impossible.

Engineering is about compromise and trade-offs. There are no perfect designs. The 737 MAX is best in class efficiency. Better than the 737 NG that it replaces and even better than Airbus' newest A320neo series. The difference is so significant that the flight plan for a 737 MAX looks dangerously under-fueled as compared to the similarly sized 737 NG that it replaces.
 
Cap'n Jack said:
I don't believe it was a single mistake considering the issues with the tankers (leaving junk in the tanks) and the Starliner (software). Boeing has lost a lot of goodwill. I see it not as a single mistake, but a corporate culture that allows shoddy work. This MCAS issue is fixed, is there another problem in an unrelated system?
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I read a good analysis of Boeing management that maintained that the problem with Boeing is that they have evolved from an engineering-centric management culture to a Wall Street-centric management culture. That has the ring of truth to me.
 
Question for all of you, would you fly on it?

Honestly I would have even before the grounding. The human factor was a major contributor to both of accidents. Both aircraft were being operated by airlines in nations with drastically different regulations and expectations of training and experience for airline crews. I believe the one FO only had 200 hours total time, he would not have even qualified to have a basic commercial license in the US, much less an ATP and a job flying a 737.
 
midwestpa24 said:
Question for all of you, would you fly on it?
...
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Yes. But it is unlikely I'll be taking the airlines anywhere anytime soon. I've had my fill of TSA nonsense and riding in the back of the aluminum tube. edit: and this has nothing to do with covid-19 - not that I blame anyone for chosing not to travel.
 
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Bob Noel said:
Yes. But it is unlikely I'll be taking the airlines anywhere anytime soon. I've had my fill of TSA nonsense and riding in the back of the aluminum tube.
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Yes there is that. I personally have not been travelling just due to all the uncertainty with COVID, so you won't probably see me on a Max or any other flying busline anytime soon.
 
Bill said:
On a US carrier? Sure, I'd fly on one tomorrow.
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Me too. I would have flown on it before all the “fixes”. Outfit like Bananastan Airlines and Goat Farms, never, no matter what company built the airplane.

Cheers
 
I would. But given my company will have travel restrictions for a long time to come, given my company is enjoying the lack of travel expenses, and given I don’t do a lot of personal travel- it will be a long time before I have the opportunity to fly.
 
After spending years teaching for an Asian first world airline, I have sworn off all third world and Asian carriers. Boeing screwed up, but the deaths would not have happened with a US career.
 
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Kristin said:
After spending years teaching for an Asian first world airline, I have sworn off all third world and Asian careers. Boeing screwed up, but the deaths would not have happened with a US career.
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I would not say it couldn't happen, but I'd say probably very unlikely. Lets face it, we've had US pilots crash perfectly good airplanes as well.
 
AlphaMike said:
That's interesting. I know nothing about the tax structure Boeing was dealing with in Seattle but it must have been pretty bad if a move to Illinois was better!
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Yeah, but Chicago traffic is awesome, so there’s that.
 
Bill said:
Glad to see these birds and pilots get back to work, I just hope there's enough customer base to support them.
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I'd have no hesitation riding one, especially on a US flag carrier.
 
Ghery said:
I'd have no hesitation riding one, especially on a US flag carrier.
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Not fear of the Max, but just that the industry is down in general. I just don't know if there is need for all of the idle birds to be RTS. I believe we're still a year or two away from a travel rebound.
 
Bill said:
Not fear of the Max, but just that the industry is down in general. I just don't know if there is need for all of the idle birds to be RTS. I believe we're still a year or two away from a travel rebound.
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Well, since the MAX is more efficient than the NG, it makes sense to return them to service on a one for one basis with the NG. IOW, mothball one NG for each MAX that is returned to service.
 
Greg Bockelman said:
Well, since the MAX is more efficient than the NG, it makes sense to return them to service on a one for one basis with the NG. IOW, mothball one NG for each MAX that is returned to service.
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OK, that makes perfect sense. If you only need a subset of the fleet, fly the most efficient birds.
 
I flew the "Death cruiser" (DC-10) for a few years. Despite all its problems, it was fun to fly (for a big airplane). The harder you pushed it, the better it flew. I flew the B-737-100-200-300 and a few hours in the -800 (POS). Jumseated plenty on the -900 (REAL POS!) Bean counters dream, no matter how bad it is performance wise. The bean counters win out when building new planes. They control the money. So building a plane that makes sense on paper, but has fundament design flaws in handling is acceptable. Wing mounted engines will always have pitch issues with power changes. The more power and farther in front of the wing will have bigger bigger pitch issues. So mask it with electronics. Electronics WILL fail at the most inopportune times. Bad aerodynamics are not acceptable, ever! When we first checked out on the -300, one of the things we saw ( and practiced) was the DRAMATIC pitch authority the engines had. I imagine that is minor compared to the MAX. I have an offer to spend a few minutes in the SIM playing with it. (class mate is an instructor in it). I would like to do that.
 
Oldmanb777 said:
When we first checked out on the -300, one of the things we saw ( and practiced) was the DRAMATIC pitch authority the engines had. I imagine that is minor compared to the MAX.
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I've never flown the Classic 737, only the NG and MAX. My only other jet with under-wing engines was the DC8.

The pitch changes with power changes on the NG and MAX is noticeably less than it was on the DC8. It's hard to quantify that, though I wouldn't call the NG/MAX response 'dramatic'. In any case, it doesn't take long to get a feel for it and to know how much to bump the trim with power changes.

They did fix a lot of things in the MAX that improve handling. The longer NGs, -800/-900, have a tendency to wag the wings with full (40°) flaps. For that reason, Flaps 30° is the 'normal' landing flap setting. That tendency is gone on the MAX so the 'normal' landing flaps setting is back to 40°. That knocks 7 or 8 knots off of VREF, which is another good thing.

Overall, the MAX handles nicer than the similarly sized NG. It also burns significantly less fuel. The fuel planning for a MAX 9, similarly sized to the NG -900, looks like it's for the significantly smaller -700 (126 seats vs. 179). The best handling jet I've flown is the 757. It is heavier and burns significantly more fuel, though, so it's no surprise that they are going away.

Bottom line is that the 737 is an airplane that only an accountant could love.
 
Bean counters,,,,,,,,,,,,,,save a nickel to spend a dollar, doesn't matter that the nickel saved, cost lives. Cheaper, cheaper cheaper is always, always better, can't understand the concept of bang for the buck, if it's cheaper, it MUST be better. Sheesh...........
 
Engineers. Spend $7M of R&D for $7M of increase revenue. You'd think math would be included in the degree plan somewhere.
 
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