fly18725

chipmaster

"Certifiable" similar to " Safe" or " met all requirements" all on the slippery slope of just enough or all they could do.

I am certain w/o MCAS the new bigger engines and where they are place is still capable and "safe." Having talked with a UA pilot that has decades flying 737, 757, 767 and now 787 I trust his take on the evolution and additions that were made to the venerable design. I simply don't buy that a airframe designed in the 60's for 1-2 hour hops and then stretched and modified and improved and now capable of 3-5 hour tran-atlantic is / was the best BA could do. Compromises were made and yes likely w/o MCAS it could be flown, but really how much training would AA/UA/WN/AS pilot needs, how did it do at the envelop corners at takeoff ( heavy, near stall, 100% thrust and extreme emergency response during extreme flying corners ) likely compromised and better like the latest very un aerodynamic stealth planes that need complex software too. Sometimes engineering band-aids ontop of band-aids can unravel in strange ways, believe me, I've seen it too many times. Sadly in this case hundreds of people died before the lessons were learned, but isn't this how it always end up, all okay till it isn't in the name of "judgement."

BF263533

My first flight on a 737 was on United almost 50 years ago. It had those narrow long tubular engines (balanced under the wing & extending beyond both the front & back of the wing"s edge) and the plane sat close to the ground. I never imagined I would be flying on a 737 long after production on the more modern 757 & 767 ceased. Why would Boeing make the old MCAS so robust if it felt it wasn't needed? Only actual extensive flight testing and operation of the737 MAX over time will resolve many of the concerns with the 737 Max.

USA_flyer

bbc.co.uk says the MCAS triggered on the Ethiopian jet.

DenverBrian

Now confirmed as a contributor to both. @:-)

spin88

This nails the "root cause" ^ In search of higher profit margins, Boeing elected to reduce staff levels and off-shore/out-source much of the design work on the 787. Part of this was sticking it to the Unions who had just made Boeing pay up... This blew up big time in the 787 business disaster (resulting in delays and extra costs so expensive that Boeing will never recoop its investment) but also - now we know worse - caused Boeing to delay investing in a new narrow-body. Then caught napping by Airbus's neo announcement, but still unwilling (or frankly unable, lacking the engineering resources, as a result of earlier staff cuts) to invest, Boeing sat on its hands until American announced it was buying the neo/A321. Just like when United did the same thing (with its A321/A319 order) Boeing finally sprang into action, but with a sense of crisis.

Faced with an outdated design, Boeing had to make major changes to the outdated airframe which compromised how it flew in fundamental ways. This would require retraining, simulators, etc. All of this would substantially increase the cost for operators. It was not that the MAX was unsafe, it was that it did not perform the same way, and had a few unpleasant aerodynamic characteristics, and as such pilots needed to know how it was different and how to fly it in situations at the margins.

But the business case for the MAX did not work with re-training, not to mention that Boeing would have to design a simulator, which would have pushed back launch of the MAX by something like a year. Retraining and delay would cause certain 737 operators to opt for the neo.

So Boeing slapped a band-aid on in the MCAS system, and adding the the problems did a crappy crappy job of it (single sensor, no disagree or warning system, allowing substantial trim movement, and finally allowing the system to re-trigger every 30 seconds, overriding pilot commands) and to top it off provided no training whatsoever on what the MCAS system did.

Now we know that two crashes, with over 300 dead were caused by the MCAS system. Boeing continued to deny and try to evade a fix, and got its regulator in its corner (whether it did so corruptly is now a subject of investigation) until the rest of the world called Boeing/FAA's B.S.

Those who said that the MAX should not be grounded were wrong (as this mornings news shows). And Boeing really undermined its reputation for building safe airplanes. This problem on the MAX will be fixed (the MCAS system will be fixed and pilots will be trained to know what the system is doing so they can know to override it and how, if need be) but this all does undercut my faith in Boeing's engineering and at this point I have zero faith they will put safety over profits, or that the FAA will make them do so.

mrswirl

I haven't read thru all the pages on this thread yet but I came across a video today of a pilot demonstrating the runaway stabilizer procedure in a 737 simulator. It's pretty enlightening to see the actual procedure in action and what pilots have to do in order to diagnose and resolve an issue in real time. From what I've read, the Ethiopian pilots had less than 40 seconds to respond prior to impact. In the video, the pilots took almost 2 minutes to recognize and declare runaway stab and then hit the manual cutout switch. It then took another 20-30 seconds just to manually adjust the stabilizer wheels. I don't see how it would be possible for any pilot to react in a similar manner in less than a minute at low altitude regardless of training.


(simulator video starts at 16:50. The rest of the video is the pilot describing pitch, elevators and stabilizers in layman's terms)

MostlyUA

They can test and operate the 737 MAX without me in the passenger seat. Thanks but no thanks.

danielSuper

How is a simulator and an extra training going to fix an inherently unstable design? Engines generate more lift in high AoA/low speed scenario, leading to nose up movements in worst time. Combined with pitch up movement from the engines during TOGA, it's probably close to negate the elevator authority. Then you have a Rube Goldberg style system good for for B2 or Su-27, trying to make an airliner not to stall. That thing is not "Safe" by any 2019 standards. It's safe for test pilots and people with ejections seat, not for 24/7 line operations with tired pilots and shady maintennance.

EmailKid

Thanks,

I had a decent undestanding and the video made it even better.

Great clip ^

Newman55

It's not an unstable design. It's just different from previous 737s (like all derivatives).

rdurlabhji

Agreed. Cute dog too.

LarryJ

They go through the procedure very slowing in the video for demonstration. There was apparently no attempt to retrim with each trim activation (re-trimming will work with an MCAS activation). They kept the airplane in control at all times so there was no immediacy to the situation--they had time to be methodical. If they were having more trouble they would have gone to the stab trim switches much quicker. The F/O make the manual trim look a lot harder than it is because he left his left arm-rest in the way.

spin88

All planes fly differently. The MAX flies differently than a 737 classic/NG. I have no doubt that pilots could fly the MAX w/o MCAS just fine. BUT they would need to be trained on it, and how to address situations that might arise and the different handling characteristics of the MAX.

MCAS is not on the plane because the plane can't fly w/o it, its there to make the MAX seem like its a NG, changing the responses so that the plane feels the same way. That was not needed for safety, nor to make the plane fly, it was only needed TO GET CARRYOVER CERTIFICATION and having that NOT TO HAVE TO RETRAIN ANYONE ON THE NEW DESIGN. Put another way, there is no engineering or aeronautical reason for MCAS, it was needed to try to make the business case for the MAX better....

coolbeans202

A number of posts over at pprune.org indicate that the MAX could not have been certified without MCAS. Below is one. Seems legit, but I obviously couldn't say for sure: https://www.pprune.org/rumours-news/...Y#post10415847