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-   -   B737MAX Recertification - Archive (https://www.flyertalk.com/forum/united-airlines-mileageplus/2031779-b737max-recertification-archive.html)

FCfree Jul 25, 2019 1:31 pm


Originally Posted by cmd320 (Post 31342000)
Yes, they could have, but they didn't. The MAX however managed to not once, but twice and in a very short period of time, very soon after introduction. The MAX issues are deeper than a simple design bug or flaw. They are indicative of the haste with which the aircraft was conceived and produced as well as the corners that were cut to keep design and training costs down.

The core problem here is that the airlines demanded an airplane where 737 pilots required minimal training to be 737-MAX qualified. To make that happen, they created MCAS to compensate for the design differences between the 737-700/800/900 and the 737-MAX. But MCAS was poorly designed. Didn't take input from both stall indicators. Didn't have logic to say ... hmmmm ... stall indicator says we are stalling, so I will nose down. Hmmm.... we are descending and gaining speed, but the stall indicator says we are still stalling. Something ain't right here!

Further, the software should have said ... hmmm ... we have been stalling for quite a while now and I have been going nose down. We are going faster and faster. The ground is getting pretty close now. Perhaps pulling up with max power would be a good idea.

Instead, it said "I don't care how close to the ground we are. If that stall indicator says we are stalling (or close to it), I will keep going nose down. I feel the need for speed, regardless of how close to the ground we are. I didn't watch Top Gun. I don't understand the concept of a HARD DECK (especially the real hard deck -- the ground). We will only be below the hard deck for a few seconds, what's the danger here? Oh my, we have been below the hard deck for quite a while now, maybe I should try something else?"

Also, the basic concept of -- an instrument is telling me something, but its possible that the instrument is telling me the wrong information. Especially when I take action based on that instrument and the problem is either staying the same or getting worse. Look at all the other facts and figure this out.

jsloan Jul 25, 2019 1:34 pm


Originally Posted by DenverBrian (Post 31342067)
Did the "previous Lion Air flight" not porpoise before it recovered? Did it not scare the bejeezus out of the passengers?

Is a plane model "safe" as long as it makes it to the ground, even if it scares the bejeezus out of the passengers every once in a while?

Please don't put words in my mouth. All I said was that if you look only at the outcomes, you can get a skewed view of reality. If the two MAX flights hadn't crashed, the MAX would still be flying, MCAS and all, despite the fact that its safety characteristics are no different than the model that's currently grounded.

USA_flyer Jul 25, 2019 1:58 pm


Originally Posted by fly18725 (Post 31341189)
Yes, A321neo has pitch up issues: https://leehamnews.com/2019/07/19/bj...itch-up-issue/



Ask Bombardier or Mitsubishi about the issues they've had...


Originally Posted by ExplorerWannabe (Post 31342079)
Airbus's design philosophy is that pilots assist the avionics instead of vice-versa (which USED to be the Boeing philosophy) so every Airbus has software equivalent to what MCAS is being accused of. MCAS was supposed to simply make the aircraft FEEL like previous generations of 737s when under manual control, matching the flight characteristics to what pilots certified on prior generations of 737s expected and would react instinctively to.

I thought MCAS was supposed to make a Max fly like an NG. Unless Airbus has a similar software running on the A320, they're not analogous. Either way, Boeing truly messed up with MCAS.


Originally Posted by fly18725 (Post 31342084)


A plane model is safe when it is certified for commercial operations.

Until it isn't.

Sykes Jul 25, 2019 2:17 pm


Originally Posted by USA_flyer (Post 31342263)
I thought MCAS was supposed to make a Max fly like an NG. Unless Airbus has a similar software running on the A320, they're not analogous. Either way, Boeing truly messed up with MCAS.

Airbus does, to an even greater degree than Boeing. The Airbus fly-by-wire system uses software to interpret inputs from the pilot's movement of the flight controls, adjust based on other data sources, and then apply movements to the aerodynamic control surfaces. One of the purposes of the system is to ensure that different models within a single type rating behave similarly. There is far more software running the flight control surfaces on an Airbus plane than there is on a Boeing one. Boeing has been moving to more fly-by-wire systems, but they generally more closely mimic mechanical controls.

Yes, the software problem here created tragic results, but using software to augment controls is nothing new or unique.

COSPILOT Jul 25, 2019 2:38 pm


Originally Posted by fly18725 (Post 31342084)


A plane model is safe when it is certified for commercial operations.

Maybe I'm missing some context in your post, but plenty of things are certified and deemed safe, until things happen that were never thought of. That includes not only commercial aircraft, but private aircraft, the space program, and even more personal items such as cars and furniture.

If we hadn't grounded the airplane, but had more crashes under similar circumstances, is there a quantity that would concern you? Is it one a month, is it only North American or Western Europe carriers that count? That's somewhat rhetorical as I assume you care, but this assumption that this was an easily recoverable event isn't fact, since we don't have the reports yet. If I fly 100 different 172's, and Cessna tells me the brand new 172 flys the same as a 1978 or a 1985, that is what I expect after hundreds of hours in type. If it does something unexpected outside of what I've dealt with in the same type for decades, that is easily something that could create confusion. Training or not, at some point you know the type airplane inside and out, and what has never happened starts to fade into that back of your mind. So when a very non-standard event occurs in new airplane sold as though it's identical to the one you know, your first reaction may not be the correct one.

Maybe not the best analogy, but if a car company added traction control or anti lock braking to a vehicle back in the 90's without disclosure to anyone, that could have created problems. The early 90's is when these features became more widestream, but not hidden by manufacturers. I could see someone not expecting either feature to be caught off guard if not told about it. Thankfully both were considered safety features and not hidden in the case of car manufacturers, in fact it was always advertised as an improvement.

So while I think a clean sheet replacement would have been best for Boeing, I'm not against the aircraft. I don't agree that airlines demanded another 737, what they likely demanded was an aircraft that didn't increase cost for them. Every client wants better efficiency at the same cost, who doesn't? Big engines and the 737 didn't work as planned, hence MCAS, and I'll bet in hindsight Boeing is questioning themselves. They are a smart company, again I don't have the hatred some do for them, and really hope they survive this.

For the benefit of our economy and frankly Boeing I hope its back in the air again sooner rather than later, even though I don't agree with how things have been handled.

fly18725 Jul 25, 2019 2:44 pm


Originally Posted by USA_flyer (Post 31342263)
I thought MCAS was supposed to make a Max fly like an NG. Unless Airbus has a similar software running on the A320, they're not analogous. Either way, Boeing truly messed up with MCAS.

I was speaking the nearly identical handling characteristics of the airplanes necessitating augmentation. There are various ways to approach the same issue.


Originally Posted by COSPILOT (Post 31342432)
Maybe I'm missing some context in your post, but plenty of things are certified and deemed safe, until things happen that were never thought of. That includes not only commercial aircraft, but private aircraft, the space program, and even more personal items such as cars and furniture.

If we hadn't grounded the airplane, but had more crashes under similar circumstances, is there a quantity that would concern you? Is it one a month, is it only North American or Western Europe carriers that count? That's somewhat rhetorical as I assume you care, but this assumption that this was an easily recoverable event isn't fact, since we don't have the reports yet. If I fly 100 different 172's, and Cessna tells me the brand new 172 flys the same as a 1978 or a 1985, that is what I expect after hundreds of hours in type. If it does something unexpected outside of what I've dealt with in the same type for decades, that is easily something that could create confusion. Training or not, at some point you know the type airplane inside and out, and what has never happened starts to fade into that back of your mind. So when a very non-standard event occurs in new airplane sold as though it's identical to the one you know, your first reaction may not be the correct one.

Maybe not the best analogy, but if a car company added traction control or anti lock braking to a vehicle back in the 90's without disclosure to anyone, that could have created problems. The early 90's is when these features became more widestream, but not hidden by manufacturers. I could see someone not expecting either feature to be caught off guard if not told about it. Thankfully both were considered safety features and not hidden in the case of car manufacturers, in fact it was always advertised as an improvement.

So while I think a clean sheet replacement would have been best for Boeing, I'm not against the aircraft. I don't agree that airlines demanded another 737, what they likely demanded was an aircraft that didn't increase cost for them. Every client wants better efficiency at the same cost, who doesn't? Big engines and the 737 didn't work as planned, hence MCAS, and I'll bet in hindsight Boeing is questioning themselves. They are a smart company, again I don't have the hatred some do for them, and really hope they survive this.

For the benefit of our economy and frankly Boeing I hope its back in the air again sooner rather than later, even though I don't agree with how things have been handled.

My point is that we will know the airplane is safe when the regulators allow it to return to operation. There are always unknown unknowns that could impact safety of the 737 - or any other product - in the future, necessitating regulatory action.

COSPILOT Jul 25, 2019 3:09 pm


Originally Posted by fly18725 (Post 31342452)
I was speaking the nearly identical handling characteristics of the airplanes necessitating augmentation. There are various ways to approach the same issue.



My point is that we will know the airplane is safe when the regulators allow it to return to operation. There are always unknown unknowns that could impact safety of the 737 - or any other product - in the future, necessitating regulatory action.

I wonder how many people are involved in improvement or approval that wouldn't have a clue how to fly an airplane? My wife is smart enough to know that I know much more than she does about airplanes, even though she is overall much smarter than me.:)

fly18725 Jul 25, 2019 3:45 pm


Originally Posted by COSPILOT (Post 31342532)
I wonder how many people are involved in improvement or approval that wouldn't have a clue how to fly an airplane? My wife is smart enough to know that I know much more than she does about airplanes, even though she is overall much smarter than me.:)

I have no idea how to fly an airplane. :)

I have spent a lot of time talking to people that do and reading material with an open mind.

DenverBrian Jul 25, 2019 3:51 pm


Originally Posted by jsloan (Post 31342163)
Please don't put words in my mouth. All I said was that if you look only at the outcomes, you can get a skewed view of reality. If the two MAX flights hadn't crashed, the MAX would still be flying, MCAS and all, despite the fact that its safety characteristics are no different than the model that's currently grounded.

If the two MAX flights hadn't crashed, but had gone through 20 minutes of porpoising before recovery and landing, I can almost guarantee you they wouldn't still be flying. @:-)

There are millions of if/then statements that can be created and floated about.

WineCountryUA Jul 25, 2019 4:05 pm

This thread is returning to its old habits of personal attacks (even if in the third person). Discuss the issues, not the posters. If you are thinking of making comments about other posters, DON'T

The rules are clear

12.2 Avoid Getting Personal
If you have a difference of opinion with another member, challenge the idea — NOT the person. Getting personal with another member is not allowed. Personal attacks, insults, baiting and flaming will not be tolerated.
This includes sweeping statements about the ability of others to comment on this situation.

Multiple Moderators have had to address multiple issues today on this thread. The Moderator Team has worked to keep this thread open as has been a source of interesting information but if a civil discussion can not be had, this thread will be closed.

WineCountryUA
UA coModerator

LarryJ Jul 25, 2019 5:50 pm


Originally Posted by DenverBrian (Post 31342690)
If the two MAX flights hadn't crashed, but had gone through 20 minutes of porpoising before recovery and landing, I can almost guarantee you they wouldn't still be flying

If the correct procedures had been applied there wouldn't have been any porpoising.

TXJeepGuy Jul 26, 2019 10:31 am

I've got a flight in October that was originally scheduled on a Max 9.

Following the announcement that they were extending the grounding, the aircraft changed to a 737-900.

This week its back to a Max 9.

Hoping that's just a placeholder and not a sign that this flight in particular is likely to be canceled.

clubord Jul 26, 2019 11:19 am


Originally Posted by TXJeepGuy (Post 31345530)
I've got a flight in October that was originally scheduled on a Max 9.

Following the announcement that they were extending the grounding, the aircraft changed to a 737-900.

This week its back to a Max 9.

Hoping that's just a placeholder and not a sign that this flight in particular is likely to be canceled.

Internally we get trips built and placed into open time on a weekly basis to cover the MAX flying, I’m on the B756.

October is past the peak summer flying season, they’ll be extra airplanes to cover that flying. I wouldn’t be concerned about getting cancelled.

TXJeepGuy Jul 26, 2019 2:18 pm


Originally Posted by clubord (Post 31345688)


Internally we get trips built and placed into open time on a weekly basis to cover the MAX flying, I’m on the B756.

October is past the peak summer flying season, they’ll be extra airplanes to cover that flying. I wouldn’t be concerned about getting cancelled.

Thanks. Its a trip to Vegas for a concert that night and I'm meeting people driving in from California- I'd rather fly in the night before if this one isn't going as the later flights won't work for me.

jsloan Jul 26, 2019 2:21 pm


Originally Posted by TXJeepGuy (Post 31346249)
Thanks. Its a trip to Vegas for a concert that night and I'm meeting people driving in from California- I'd rather fly in the night before if this one isn't going as the later flights won't work for me.

On the off chance that your flight is cancelled, UA will move you to the previous night's flight at no charge.

That said, I agree with clubord. Once UA gets through the next couple of weeks, the schedule starts to lighten up, and I suspect that cancellations will be rare.


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