Moderators: jsumali2, richierich, ua900, PanAm_DC10, hOMSaR

 
AABusDrvr
Posts: 153
Joined: Sat Dec 03, 2016 6:48 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 1:25 pm

XRAYretired wrote:
planecane wrote:
flyingphil wrote:
Regulators knew before crashes that 737 MAX trim control was confusing in some conditions: document

https://www.reuters.com/article/us-ethi ... SKCN1RA0DP

U.S. and European regulators knew at least two years before a Lion Air crash that the usual method for controlling the Boeing 737 MAX's nose angle might not work in conditions similar to those in two recent disasters, a document shows.

I have not seen this before.. sorry if it has been posted before, not easy to keep up with the MAX news.

Doesn't look good for Boeing or the FAA.

Q4 is almost upon us and Boeing has not submitted the fix to the FAA and the MAX10 has yet to fly..


What isn't made clear by the article (which is probably the result of the news media rushing to get the "scoop" without first getting all the facts) is WHY the electric trim wouldn't work in certain conditions. The article says:

It specifically noted that at speeds greater than 230 knots (265mph, 425kph) with flaps retracted, pilots might have to use the wheel in the cockpit’s center console rather than an electric thumb switch on the control yoke.


Based upon the conditions, it appears that the reason is somehow related to the MCAS software. But, from what we know, trimming opposite to MCAS would have interrupted it temporarily. It doesn't make sense that the same motor that drives the stabilizer movement just fine on the NG under these conditions would reach some kind of physical limit on the MAX. It's the same stabilizer so the aerodynamic forces should be roughly equivalent under the same conditions. Does this mean that a software limit was added to MCAS to not allow the pilot to electrically trim out all of the MCAS input? IF that is the case, then the runaway stabilizer NNC as written would not work once the MCAS runaway progressed beyond a certain point.

I guess for clarification we either need more detailed leaks or will have to wait for the final report on the Lion Air crash.

Again if you read the EASA finding from the original certification. This sentence may provide the clue:

'EASA POSITION
Boeing set the thumb switch limits in order to increase the level of safety for out-of-trim dive characteristics(CS 25.255(a)(1)). The resulting thumb switch limits require an alternative trim method to meet CS 25.161trim requirements in certain corners of the operational envelope.'

It may indeed indicate another 'minor' change to flight controls that was not disclosed.

Ray


I missed this back in March when it was originally published. I just read the EASA document, and then I went back and looked at my MAX differences material. We were simply told "the trim authority for main electric and autopilot trim is less than for manual trim". For flight crew, this is a much bigger deal than MCAS, and I'm extremely disappointed that Boeing and the FAA didn't feel we needed to know the specifics.

Once I have my coffee, if everyone is ready to grab the pitch forks, fire up the torches and head over to Boeing and the FAA I'm in.
 
User avatar
Revelation
Posts: 24370
Joined: Wed Feb 09, 2005 9:37 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 1:34 pm

PixelFlight wrote:
The confusion is to believe that "understand the basics of flight" is enough to safely avoid crashes in situation like the JT610 and ET302. This do not mean that it's impossible to avoid, like the JT43 have do with an extra pilot. That mean that for commercial flight it's not safe enough to avoid.

I guess we're never going to know because the airlines seem to be comfortable putting airmen who do not demonstrate that they "understand the basics of flight" into the cockpit, and relying on the automation to not cause the airmen challenges at a low enough rate to keep the hull loss rate low enough to allow for acceptable insurance rates. The occasional AF447 or OZ214 will be viewed as an outlier, and the airlines will save lots of cash not having to find pilots who do understand the basics of flight, or who can puzzle out the reason why of all the things Boeing could have put right under their thumbs they chose to put trim cut out switches, etc.
Wake up to find out that you are the eyes of the world
The heart has its beaches, its homeland and thoughts of its own
Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own
 
frmrCapCadet
Posts: 4252
Joined: Thu May 29, 2008 8:24 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 3:10 pm

https://www.seattletimes.com/business/b ... x-crashes/

A Bloomberg article posted in the Seattle Times.

A committee of outside experts has reported back to Boeing recommendations for changes if reporting. Short version is that program engineers will report to Boeing's Senior Engineer who reports to the CEO. Safety issues will report to a newly(?) formed Boeing Safety Committee. Program managers will not have the responsibility (or privilege) to block issues from these higher levels.
Buffet: the airline business...has eaten up capital...like..no other (business)
 
ShamrockBoi330
Posts: 353
Joined: Fri Sep 21, 2018 3:28 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 3:19 pm

Boeing settles first Lion Air lawsuits for at least $1.2 million apiece - reuters

https://reut.rs/2mJXQJN
 
Sooner787
Posts: 2702
Joined: Thu Jul 18, 2013 1:44 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 3:54 pm

I think the good news for Boeing is it's looking more and more that the 737-8's and -9's will be cleared for RTS by Thanksgiving,
but the ongoing flight test programs for the 737-7's , -10's and the 777X will have additional hoops
to jump thru, but if it's in the name of safety, that's a good thing :)
 
ShamrockBoi330
Posts: 353
Joined: Fri Sep 21, 2018 3:28 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 4:06 pm

Sooner787 wrote:
I think the good news for Boeing is it's looking more and more that the 737-8's and -9's will be cleared for RTS by Thanksgiving,
but the ongoing flight test programs for the 737-7's , -10's and the 777X will have additional hoops
to jump thru, but if it's in the name of safety, that's a good thing :)


Just curious if i have missed something, why do you think RTS by Thanksgiving?

Anything i've read is pointing to later at best? From announcement of certification flight, (no announcements yet) at least 4 to 6 weeks for certification if successful nothing new turns up... and the FAA have not received MCAS 2.0 yet, have they? I know they was it in production mode and not Beta for testing. Plus other points, manual wheel trim etc?

Not trying to be smart, but am curious about the optimism?

Either way, still not early Q4 per previous guidance and not aware of any new guidance coming from Boeing?
 
ArchGuy1
Posts: 1508
Joined: Wed Jul 10, 2019 11:35 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 5:03 pm

It is possible that the 737MAX may start flying in different countries at different times.
 
art
Posts: 3459
Joined: Tue Feb 08, 2005 11:46 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 5:19 pm

flyingphil wrote:
Regulators knew before crashes that 737 MAX trim control was confusing in some conditions: document

https://www.reuters.com/article/us-ethi ... SKCN1RA0DP

U.S. and European regulators knew at least two years before a Lion Air crash that the usual method for controlling the Boeing 737 MAX's nose angle might not work in conditions similar to those in two recent disasters, a document shows.

I have not seen this before.. sorry if it has been posted before, not easy to keep up with the MAX news.

Doesn't look good for Boeing or the FAA.

Q4 is almost upon us and Boeing has not submitted the fix to the FAA and the MAX10 has yet to fly..


I note this from the Reuters story (my emboldening):

The undated EASA certification document, available online, was issued in February 2016, an agency spokesman said.

It specifically noted that at speeds greater than 230 knots (265mph, 425kph) with flaps retracted, pilots might have to use the wheel in the cockpit’s center console rather than an electric thumb switch on the control yoke.

EASA and the U.S. Federal Aviation Administration (FAA) ultimately determined that set-up was safe enough for the plane to be certified, with the European agency citing training plans and the relative rarity of conditions requiring the trim wheel.


So if EASA assent was based on/conditional on training for unusual trim events(?). how come pilots did not receive that training? Doesn't look good for EASA, either, does it?
 
DenverTed
Posts: 475
Joined: Wed Mar 27, 2019 11:12 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 6:24 pm

So the electric trim gives out at high loads? And the manual wheel trim is geared so the pilots deal with the higher loads that the motor can't?
 
kalvado
Posts: 2856
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 6:46 pm

DenverTed wrote:
So the electric trim gives out at high loads? And the manual wheel trim is geared so the pilots deal with the higher loads that the motor can't?

This is one way to read it, and I wouldn't be surprized if that is the case.
THe other possibility is that Boeing wanted to limit how much pilots can flick switches so that they don't trim too far - or so that runaway due to faulty switch doesn't go too far. If you really-really-really need more than normal, (but why?) - prove your intention by spinning the wheel.
Possibly both are true to some extent. Way up the thread I speculated that the trim motor can be only that powerful (remember, power translates into weight) and jackscrew can handle only that much load.
 
WIederling
Posts: 9311
Joined: Sun Sep 13, 2015 2:15 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 7:10 pm

art wrote:
So if EASA assent was based on/conditional on training for unusual trim events(?). how come pilots did not receive that training? Doesn't look good for EASA, either, does it?


Because the FAA ignored an agreement achieved with EASA in their final certification stamping?

Interesting jump in causality.
Murphy is an optimist
 
sgrow787
Posts: 450
Joined: Fri May 16, 2014 8:12 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 8:06 pm

Question: Doesnt the DFDR plot for JT043 (the dead seat saved Lion Air flight just before the crash flight) show at 14:33:54 manual wheel being used to trim ANU about 2 deg? Do we know what the airspeed was at that time? My copy of the JT610 preliminary report does not have range values on some of the plot scales.

(There is no electric trim switch activity, and the pitch trim value shows ANU at the same time, so must be manual wheel.)
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
User avatar
Revelation
Posts: 24370
Joined: Wed Feb 09, 2005 9:37 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 8:17 pm

frmrCapCadet wrote:
https://www.seattletimes.com/business/boeing-aerospace/boeing-revamps-safety-oversight-after-review-of-737-max-crashes/

A Bloomberg article posted in the Seattle Times.

A committee of outside experts has reported back to Boeing recommendations for changes if reporting. Short version is that program engineers will report to Boeing's Senior Engineer who reports to the CEO. Safety issues will report to a newly(?) formed Boeing Safety Committee. Program managers will not have the responsibility (or privilege) to block issues from these higher levels.

Yes, this is the outcome of the investigation kicked off by Boeing's BoD, and whose report was leaked a week or so ago.

The linked article says:

Its review “has found that the 737 Max was certified for service following successful completion of the FAA’s standard, extensive and comprehensive certification process and protocols,” he said. “Further, our committee found no competing requirements in the safety certification of the Max that would in any way have compromised the safeness of the Max.”

And:

Dennis Muilenburg, Boeing’s chief executive officer, has already begun implementing some of the proposals made following a five-month internal review, Giambastiani said.

“He has not wasted time in doing this. And he has clearly, as the chairman, not put any restrictions on us. We had full control,” said Giambastiani, who spearheaded the examination of the company’s airplane design policies and processes. “Dennis has the board’s confidence.”

I know people will scream that this is a whitewash, but the changes to the organizational structure should give engineers and safety team members more independence from product line management than they used to have, so hopefully this is a change that does show benefits with regards to design quality and safety.

EDIT: The actual presser is at https://boeing.mediaroom.com/2019-09-25 ... -to-Safety

One part may be of interest:

Re-examine flight deck design and operation: The board recommends that Boeing partner with its airline customers and others in the industry to re-examine assumptions around flight deck design and operation. Design assumptions have evolved over time, and the company should ensure flight deck designs continue to anticipate the needs of the changing demographics and future pilot populations. Additionally, the company should work with all aviation stakeholders to advise and recommend general pilot training, methods and curricula – where warranted, above and beyond those recommended in a traditional training program – for all commercial aircraft manufactured by the company.

I wonder if this is aimed at the diploma mill at Lion City?
Wake up to find out that you are the eyes of the world
The heart has its beaches, its homeland and thoughts of its own
Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own
 
AirBoat
Posts: 61
Joined: Sun Jan 18, 2015 11:58 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 8:43 pm

It would be interesting to know what the duty cycle is on the stabilizer trim motor. (where 100% duty cycle is continuous max torque on motor)
normal operation near in trim would only require a fraction of full torque, but in the mcas failure mode you might need full torque for a long period when trimming nose up.
The duty cycle is no doubt specified somewhere in the faa rules. I could not find it.

The failure mode of stickshaker and mcas that increases yoke backforce is ok for nose up but completely wrong for nose level or nose down.
 
hivue
Posts: 2078
Joined: Tue Feb 26, 2013 2:26 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 8:54 pm

planecane wrote:
Does this mean that a software limit was added to MCAS to not allow the pilot to electrically trim out all of the MCAS input? IF that is the case, then the runaway stabilizer NNC as written would not work once the MCAS runaway progressed beyond a certain point.


It's likely the runaway pitch trim NNC has a pretty short shelf life under any circumstances -- a "real" runaway trim, MCAS-caused "runaway trim," or whatever. If the crew is not sufficiently alert to run the NNC before things go too far even with a "real" runaway trim then bad stuff will happen.
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
kalvado
Posts: 2856
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 8:55 pm

Revelation wrote:
frmrCapCadet wrote:
https://www.seattletimes.com/business/boeing-aerospace/boeing-revamps-safety-oversight-after-review-of-737-max-crashes/

A Bloomberg article posted in the Seattle Times.

A committee of outside experts has reported back to Boeing recommendations for changes if reporting. Short version is that program engineers will report to Boeing's Senior Engineer who reports to the CEO. Safety issues will report to a newly(?) formed Boeing Safety Committee. Program managers will not have the responsibility (or privilege) to block issues from these higher levels.

Yes, this is the outcome of the investigation kicked off by Boeing's BoD, and whose report was leaked a week or so ago.

The linked article says:

Its review “has found that the 737 Max was certified for service following successful completion of the FAA’s standard, extensive and comprehensive certification process and protocols,” he said. “Further, our committee found no competing requirements in the safety certification of the Max that would in any way have compromised the safeness of the Max.”

And:

Dennis Muilenburg, Boeing’s chief executive officer, has already begun implementing some of the proposals made following a five-month internal review, Giambastiani said.

“He has not wasted time in doing this. And he has clearly, as the chairman, not put any restrictions on us. We had full control,” said Giambastiani, who spearheaded the examination of the company’s airplane design policies and processes. “Dennis has the board’s confidence.”

I know people will scream that this is a whitewash, but the changes to the organizational structure should give engineers and safety team members more independence from product line management than they used to have, so hopefully this is a change that does show benefits with regards to design quality and safety.

EDIT: The actual presser is at https://boeing.mediaroom.com/2019-09-25 ... -to-Safety

One part may be of interest:

Re-examine flight deck design and operation: The board recommends that Boeing partner with its airline customers and others in the industry to re-examine assumptions around flight deck design and operation. Design assumptions have evolved over time, and the company should ensure flight deck designs continue to anticipate the needs of the changing demographics and future pilot populations. Additionally, the company should work with all aviation stakeholders to advise and recommend general pilot training, methods and curricula – where warranted, above and beyond those recommended in a traditional training program – for all commercial aircraft manufactured by the company.

I wonder if this is aimed at the diploma mill at Lion City?

Were there any other crashes where the change of corporate reporting procedures at manufacturer was one of corrective actions? Maybe Challenger?
 
User avatar
PixelFlight
Posts: 1019
Joined: Thu Nov 08, 2018 11:09 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 9:05 pm

AirBoat wrote:
It would be interesting to know what the duty cycle is on the stabilizer trim motor. (where 100% duty cycle is continuous max torque on motor)
normal operation near in trim would only require a fraction of full torque, but in the mcas failure mode you might need full torque for a long period when trimming nose up.
The duty cycle is no doubt specified somewhere in the faa rules. I could not find it.

The failure mode of stickshaker and mcas that increases yoke backforce is ok for nose up but completely wrong for nose level or nose down.

From the 737-8 MAX schematic there are "MAIN HIGH SPEED" and "A/P TRIM SPEEF" signals at the input of the stab trim controller. The torque on the trim motor is probably defined by the trim motor controller according to those signals.

http://avherald.com/img/ethiopian_b38m_et-avj_190310_10.jpg
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
XRAYretired
Posts: 870
Joined: Fri Mar 15, 2019 11:21 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 9:22 pm

sgrow787 wrote:
Question: Doesnt the DFDR plot for JT043 (the dead seat saved Lion Air flight just before the crash flight) show at 14:33:54 manual wheel being used to trim ANU about 2 deg? Do we know what the airspeed was at that time? My copy of the JT610 preliminary report does not have range values on some of the plot scales.

(There is no electric trim switch activity, and the pitch trim value shows ANU at the same time, so must be manual wheel.)

Looks like ~250kts.
avherald.com/files/lionair_b38m_pk-lqp_jakarta_181029_knkt_data.pdf

Ray
 
planecane
Posts: 1572
Joined: Thu Feb 09, 2017 4:58 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Wed Sep 25, 2019 10:39 pm

hivue wrote:
planecane wrote:
Does this mean that a software limit was added to MCAS to not allow the pilot to electrically trim out all of the MCAS input? IF that is the case, then the runaway stabilizer NNC as written would not work once the MCAS runaway progressed beyond a certain point.


It's likely the runaway pitch trim NNC has a pretty short shelf life under any circumstances -- a "real" runaway trim, MCAS-caused "runaway trim," or whatever. If the crew is not sufficiently alert to run the NNC before things go too far even with a "real" runaway trim then bad stuff will happen.


That's not true IF the electric trim has sufficient authority to counteract the runaway.
 
sgrow787
Posts: 450
Joined: Fri May 16, 2014 8:12 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 12:05 am

DenverTed wrote:
So the electric trim gives out at high loads? And the manual wheel trim is geared so the pilots deal with the higher loads that the motor can't?

Nope. My understanding is, just going by what Ive heard in this thread, that the electrim trim works for all loads, and is the reason its been said you want to alleviate load on the stab by using electric trim, before hitting the CUTOUT switches and being forced to do manual wheel trim. Which seems counterintuitive because the manual wheel should be the ultimate backup (ie if the electric trim fails).
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
sgrow787
Posts: 450
Joined: Fri May 16, 2014 8:12 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 12:20 am

planecane wrote:
hivue wrote:
planecane wrote:
Does this mean that a software limit was added to MCAS to not allow the pilot to electrically trim out all of the MCAS input? IF that is the case, then the runaway stabilizer NNC as written would not work once the MCAS runaway progressed beyond a certain point.


It's likely the runaway pitch trim NNC has a pretty short shelf life under any circumstances -- a "real" runaway trim, MCAS-caused "runaway trim," or whatever. If the crew is not sufficiently alert to run the NNC before things go too far even with a "real" runaway trim then bad stuff will happen.


That's not true IF the electric trim has sufficient authority to counteract the runaway.


No one's mentioned it yet, but looking at the pitch trim line in the ET302 DFDR plot, its apparent that the electric trim authority is somewhere around 0.15 deg/second, compared to 0.25 for MCAS 1.0. So, for 2.5 deg AND after one 10-second MCAS cycle, it would take you 17 sec of etrim ANU to get back to stable.

As for Ray's assertion electric trim was limited to 2.3 deg ANU, that is hard to tell from the DFDR pitch trim line. Since one would expect slightly progressive AND with increasing airspeeds, which in the case of ET302, was up to and through VMO.
Just one sensor,
Oh just one se-en-sor,
Just one sensor,
Ooh ooh oo-ooh
Oo-oo-ooh.
 
RickNRoll
Posts: 1869
Joined: Fri Jan 06, 2012 9:30 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 12:48 am

XRAYretired wrote:
planecane wrote:
flyingphil wrote:
Regulators knew before crashes that 737 MAX trim control was confusing in some conditions: document

https://www.reuters.com/article/us-ethi ... SKCN1RA0DP

U.S. and European regulators knew at least two years before a Lion Air crash that the usual method for controlling the Boeing 737 MAX's nose angle might not work in conditions similar to those in two recent disasters, a document shows.

I have not seen this before.. sorry if it has been posted before, not easy to keep up with the MAX news.

Doesn't look good for Boeing or the FAA.

Q4 is almost upon us and Boeing has not submitted the fix to the FAA and the MAX10 has yet to fly..


What isn't made clear by the article (which is probably the result of the news media rushing to get the "scoop" without first getting all the facts) is WHY the electric trim wouldn't work in certain conditions. The article says:

It specifically noted that at speeds greater than 230 knots (265mph, 425kph) with flaps retracted, pilots might have to use the wheel in the cockpit’s center console rather than an electric thumb switch on the control yoke.


Based upon the conditions, it appears that the reason is somehow related to the MCAS software. But, from what we know, trimming opposite to MCAS would have interrupted it temporarily. It doesn't make sense that the same motor that drives the stabilizer movement just fine on the NG under these conditions would reach some kind of physical limit on the MAX. It's the same stabilizer so the aerodynamic forces should be roughly equivalent under the same conditions. Does this mean that a software limit was added to MCAS to not allow the pilot to electrically trim out all of the MCAS input? IF that is the case, then the runaway stabilizer NNC as written would not work once the MCAS runaway progressed beyond a certain point.

I guess for clarification we either need more detailed leaks or will have to wait for the final report on the Lion Air crash.

Again if you read the EASA finding from the original certification. This sentence may provide the clue:

'EASA POSITION
Boeing set the thumb switch limits in order to increase the level of safety for out-of-trim dive characteristics(CS 25.255(a)(1)). The resulting thumb switch limits require an alternative trim method to meet CS 25.161trim requirements in certain corners of the operational envelope.'

It may indeed indicate another 'minor' change to flight controls that was not disclosed.

Ray


This is what happens when you continually implement hacks and patches on an aging system. Each change throws something else out of balance, which requires more patching and hacking away. They you prop it up, put some lipstick on it and hope it stays just so.
 
RickNRoll
Posts: 1869
Joined: Fri Jan 06, 2012 9:30 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 2:29 am

frmrCapCadet wrote:
https://www.seattletimes.com/business/boeing-aerospace/boeing-revamps-safety-oversight-after-review-of-737-max-crashes/

A Bloomberg article posted in the Seattle Times.

A committee of outside experts has reported back to Boeing recommendations for changes if reporting. Short version is that program engineers will report to Boeing's Senior Engineer who reports to the CEO. Safety issues will report to a newly(?) formed Boeing Safety Committee. Program managers will not have the responsibility (or privilege) to block issues from these higher levels.


A very sensible proposal and one that addresses the main issue with this grounding, managers who are pressured to place profit and share price ahead of other important considerations.
 
User avatar
flyingphil
Posts: 312
Joined: Wed May 16, 2007 2:56 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 5:38 am

“Boeing calls in American Airlines and others for 737 Max training as it waits for clearance to fly”


https://www.dallasnews.com/business/air ... ZgAio3xJY/

“ American Airlines is among carriers sending pilots to 737 Max training this week in Miami as Boeing intensifies its efforts to get the jets recertified and back in the air.

Boeing spokesman Charles Bickers said 737 Max operators were invited to training sessions that will take place through mid-October, similar to training sessions it held in March and April. The first of this round of training sessions are in Miami this week, with others to follow in the United Kingdom, Turkey, China and Singapore.“

“ American Airlines has one 737 Max flight simulator that should be ready by the end of October, although it's not anticipated that additional training will be needed for pilots who previously operated the 737 Max.”

Seems a bit premature..
Another obstacle for RTS will be the lack of 737MAX Simulators.. and do the simulators faithfully reproduce MCAS?
So do they have to react in 3 seconds to MCAS failure to pass the test ??
 
WIederling
Posts: 9311
Joined: Sun Sep 13, 2015 2:15 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 7:10 am

sgrow787 wrote:
DenverTed wrote:
So the electric trim gives out at high loads? And the manual wheel trim is geared so the pilots deal with the higher loads that the motor can't?

Nope. My understanding is, just going by what Ive heard in this thread, that the electrim trim works for all loads, and is the reason its been said you want to alleviate load on the stab by using electric trim, before hitting the CUTOUT switches and being forced to do manual wheel trim. Which seems counterintuitive because the manual wheel should be the ultimate backup (ie if the electric trim fails).

Wasn't "see saw flying while trimming" the ultimate method to get away from overwhelmed trim arrangements ( electric, manual)?
High elevator deflection from countering major miss-trim creating high reactive loads on the spindle drive that work against getting back in trim.
Murphy is an optimist
 
WIederling
Posts: 9311
Joined: Sun Sep 13, 2015 2:15 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 7:33 am

RickNRoll wrote:
They you prop it up, put some lipstick on it and hope it stays just so.


There is a new product around: Fiber reinforced lipstick "Fiber Gloss Ultra (TM)" :-)
Murphy is an optimist
 
User avatar
par13del
Posts: 10337
Joined: Sun Dec 18, 2005 9:14 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 10:41 am

flyingphil wrote:
Seems a bit premature..
Another obstacle for RTS will be the lack of 737MAX Simulators.. and do the simulators faithfully reproduce MCAS?
So do they have to react in 3 seconds to MCAS failure to pass the test ??

I thought the whole point of the grounding was to correct MCAS and now whatever other issues were found in the interim, is it your contention that the latest version of MCAS and its required responses by the pilots is the same as the original version?

As for the simulators, if they go from iPAD sessions to simulators, how much time and any specific training are the regulators talking about? We hear talk of additional training and simulator time, but as with everything else, we have no details, unfortunately, we have no one speculating on what they would be.

In any event, we have 4 days to go to end September before the fix submission deadline.
 
XRAYretired
Posts: 870
Joined: Fri Mar 15, 2019 11:21 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 10:45 am

sgrow787 wrote:
planecane wrote:
hivue wrote:

It's likely the runaway pitch trim NNC has a pretty short shelf life under any circumstances -- a "real" runaway trim, MCAS-caused "runaway trim," or whatever. If the crew is not sufficiently alert to run the NNC before things go too far even with a "real" runaway trim then bad stuff will happen.


That's not true IF the electric trim has sufficient authority to counteract the runaway.


No one's mentioned it yet, but looking at the pitch trim line in the ET302 DFDR plot, its apparent that the electric trim authority is somewhere around 0.15 deg/second, compared to 0.25 for MCAS 1.0. So, for 2.5 deg AND after one 10-second MCAS cycle, it would take you 17 sec of etrim ANU to get back to stable.

As for Ray's assertion electric trim was limited to 2.3 deg ANU, that is hard to tell from the DFDR pitch trim line. Since one would expect slightly progressive AND with increasing airspeeds, which in the case of ET302, was up to and through VMO.

Its been mentioned several times that the Electrical Trim rate is slower than MCAS Trim rate.
I made no assertion. Simply quoted from the formally issue preliminary report text.

Ray
 
planecane
Posts: 1572
Joined: Thu Feb 09, 2017 4:58 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 11:09 am

XRAYretired wrote:
sgrow787 wrote:
planecane wrote:

That's not true IF the electric trim has sufficient authority to counteract the runaway.


No one's mentioned it yet, but looking at the pitch trim line in the ET302 DFDR plot, its apparent that the electric trim authority is somewhere around 0.15 deg/second, compared to 0.25 for MCAS 1.0. So, for 2.5 deg AND after one 10-second MCAS cycle, it would take you 17 sec of etrim ANU to get back to stable.

As for Ray's assertion electric trim was limited to 2.3 deg ANU, that is hard to tell from the DFDR pitch trim line. Since one would expect slightly progressive AND with increasing airspeeds, which in the case of ET302, was up to and through VMO.

Its been mentioned several times that the Electrical Trim rate is slower than MCAS Trim rate.
I made no assertion. Simply quoted from the formally issue preliminary report text.

Ray

The rate isn't really relevant as MCAS isn't acting simultaneously with the manual electric counter trim. What is relevant is if the manual electric trim had the authority to completely counteract the MCAS AND trim. If it did not then an MCAS runaway was not recoverable (without the manual wheel and roller coaster procedure) if not recognized within a few seconds (exact time determined by how much authority manual electric trim had).
 
User avatar
PixelFlight
Posts: 1019
Joined: Thu Nov 08, 2018 11:09 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 11:50 am

planecane wrote:
XRAYretired wrote:
sgrow787 wrote:

No one's mentioned it yet, but looking at the pitch trim line in the ET302 DFDR plot, its apparent that the electric trim authority is somewhere around 0.15 deg/second, compared to 0.25 for MCAS 1.0. So, for 2.5 deg AND after one 10-second MCAS cycle, it would take you 17 sec of etrim ANU to get back to stable.

As for Ray's assertion electric trim was limited to 2.3 deg ANU, that is hard to tell from the DFDR pitch trim line. Since one would expect slightly progressive AND with increasing airspeeds, which in the case of ET302, was up to and through VMO.

Its been mentioned several times that the Electrical Trim rate is slower than MCAS Trim rate.
I made no assertion. Simply quoted from the formally issue preliminary report text.

Ray

The rate isn't really relevant as MCAS isn't acting simultaneously with the manual electric counter trim. What is relevant is if the manual electric trim had the authority to completely counteract the MCAS AND trim. If it did not then an MCAS runaway was not recoverable (without the manual wheel and roller coaster procedure) if not recognized within a few seconds (exact time determined by how much authority manual electric trim had).

It's clear that an electrical trim motor is better than trim wheels and related cables. But the 737 NG and MAX only have a single trim motor for that critical control surface, so a backup is required. For example on the A350, that backup is a backup trim motor driven from a backup power source and commanded by backup trim switches. No trim wheels anymore, so not authority issue even in case of a extreme trim or if the primary motor receive erratic commands: just disable it.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
morrisond
Posts: 2736
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 12:07 pm

planecane wrote:
XRAYretired wrote:
sgrow787 wrote:

No one's mentioned it yet, but looking at the pitch trim line in the ET302 DFDR plot, its apparent that the electric trim authority is somewhere around 0.15 deg/second, compared to 0.25 for MCAS 1.0. So, for 2.5 deg AND after one 10-second MCAS cycle, it would take you 17 sec of etrim ANU to get back to stable.

As for Ray's assertion electric trim was limited to 2.3 deg ANU, that is hard to tell from the DFDR pitch trim line. Since one would expect slightly progressive AND with increasing airspeeds, which in the case of ET302, was up to and through VMO.

Its been mentioned several times that the Electrical Trim rate is slower than MCAS Trim rate.
I made no assertion. Simply quoted from the formally issue preliminary report text.

Ray

The rate isn't really relevant as MCAS isn't acting simultaneously with the manual electric counter trim. What is relevant is if the manual electric trim had the authority to completely counteract the MCAS AND trim. If it did not then an MCAS runaway was not recoverable (without the manual wheel and roller coaster procedure) if not recognized within a few seconds (exact time determined by how much authority manual electric trim had).


Even one full activation of MCAS wouldn't crash the plane - it would take a few cycles to get the plane to the point where it was unrecoverable over 30-40 seconds if not counteracted at all and you didn't pull back the thrust. It wasn't a case of don't recognize it within three seconds and you are dead.
 
AABusDrvr
Posts: 153
Joined: Sat Dec 03, 2016 6:48 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 12:20 pm

par13del wrote:
flyingphil wrote:
Seems a bit premature..
Another obstacle for RTS will be the lack of 737MAX Simulators.. and do the simulators faithfully reproduce MCAS?
So do they have to react in 3 seconds to MCAS failure to pass the test ??

I thought the whole point of the grounding was to correct MCAS and now whatever other issues were found in the interim, is it your contention that the latest version of MCAS and its required responses by the pilots is the same as the original version?

As for the simulators, if they go from iPAD sessions to simulators, how much time and any specific training are the regulators talking about? We hear talk of additional training and simulator time, but as with everything else, we have no details, unfortunately, we have no one speculating on what they would be.

In any event, we have 4 days to go to end September before the fix submission deadline.


Since there wont be any physical changes to the flight deck, just to the FCC software, I'd imagine the pilot response will be the same as it's been from the beginning, treat it as a runaway stabilizer.

The rumor, at least at my airline, is no MAX specific simulator training will be involved for right now, when we start flying them again. I'd imagine any training will just be a review of the system changes, and a focus on recognition. I will bet the next recurrent training cycle, everyone MAX or NG will see a runaway stabilizer scenario.
 
frmrCapCadet
Posts: 4252
Joined: Thu May 29, 2008 8:24 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 1:00 pm

Again I say simulators between the $15 million and the standard MS Flight Simulator would be useful. It could also address part of the concerns Airbus has raised with pilot training. And as well why aren't small planes available free for a few hours a year for every pilot?
Buffet: the airline business...has eaten up capital...like..no other (business)
 
mjoelnir
Posts: 9386
Joined: Sun Feb 03, 2013 11:06 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 1:16 pm

morrisond wrote:
planecane wrote:
XRAYretired wrote:
Its been mentioned several times that the Electrical Trim rate is slower than MCAS Trim rate.
I made no assertion. Simply quoted from the formally issue preliminary report text.

Ray

The rate isn't really relevant as MCAS isn't acting simultaneously with the manual electric counter trim. What is relevant is if the manual electric trim had the authority to completely counteract the MCAS AND trim. If it did not then an MCAS runaway was not recoverable (without the manual wheel and roller coaster procedure) if not recognized within a few seconds (exact time determined by how much authority manual electric trim had).


Even one full activation of MCAS wouldn't crash the plane - it would take a few cycles to get the plane to the point where it was unrecoverable over 30-40 seconds if not counteracted at all and you didn't pull back the thrust. It wasn't a case of don't recognize it within three seconds and you are dead.


The first question is can the crew counteract to MCAS? If the electrical trim movement is limited and the manual wheel does not budge, it would be difficult.

Cutting thrust increases the down pitch considerable.
 
AABusDrvr
Posts: 153
Joined: Sat Dec 03, 2016 6:48 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 1:21 pm

frmrCapCadet wrote:
Again I say simulators between the $15 million and the standard MS Flight Simulator would be useful. It could also address part of the concerns Airbus has raised with pilot training. And as well why aren't small planes available free for a few hours a year for every pilot?



Having a fleet of small airplanes (or contracting with some training provider for use of small airplanes) would be a huge expense, plus the issue of paying the pilots to go out and fly them, and the loss of the pilot for line flying during that time. The airlines wont spend any more than they absolutely have to, unless it's forced by regulation.

It made sense back when people were flight engineers for decades, for the airlines to have basic simulators (some even had link trainers) or airplanes available for the FE's to keep up basic flying skills. But now that everyone has a window seat, I can't see it happening.
 
frmrCapCadet
Posts: 4252
Joined: Thu May 29, 2008 8:24 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 1:39 pm

So new would-be pilots put themselves in horrible debt and years of low wages often with terrible schedules flying small planes until they get into a seat of a mainline airline. This may not describe the European situation. Then they become computer managers and never really fly again unless a disaster happens - at which point they suddenly need to become great aviators. This is somewhat an unfair exaggeration. But:

Airbus, Boeing, the NTSB and I hope the FAA (and likely European equivalents) are thinking pilot training and skills are not as high as they should be. So what will change? AABusDriver - your post could be seen as saying the status quo is enough. What changes do you see needed?
Buffet: the airline business...has eaten up capital...like..no other (business)
 
2175301
Posts: 1870
Joined: Wed May 16, 2007 11:19 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 1:57 pm

mjoelnir wrote:
morrisond wrote:
planecane wrote:
The rate isn't really relevant as MCAS isn't acting simultaneously with the manual electric counter trim. What is relevant is if the manual electric trim had the authority to completely counteract the MCAS AND trim. If it did not then an MCAS runaway was not recoverable (without the manual wheel and roller coaster procedure) if not recognized within a few seconds (exact time determined by how much authority manual electric trim had).


Even one full activation of MCAS wouldn't crash the plane - it would take a few cycles to get the plane to the point where it was unrecoverable over 30-40 seconds if not counteracted at all and you didn't pull back the thrust. It wasn't a case of don't recognize it within three seconds and you are dead.


The first question is can the crew counteract to MCAS? If the electrical trim movement is limited and the manual wheel does not budge, it would be difficult.

Cutting thrust increases the down pitch considerable.


Actually, there is not even a question on if a pilot/co-pilot can use manual electric trim to counteract MCAS driven trim movements. The evidence that it can be done is quite clear from the Lion Air crash. The Pilot used manual electric trim many times for many minutes to return trim to a normal status when faced with the MCAS failure, and retained effective control of the aircraft. The Pilot then turned control over to the Co-Pilot so he could work on troubleshooting, and the aircraft crashed with the Co-Pilot at the controls (who did not input manual electric trim enough to counteract the malfunctioning MCAS).

Have a great day,
 
morrisond
Posts: 2736
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 2:07 pm

mjoelnir wrote:
morrisond wrote:
planecane wrote:
The rate isn't really relevant as MCAS isn't acting simultaneously with the manual electric counter trim. What is relevant is if the manual electric trim had the authority to completely counteract the MCAS AND trim. If it did not then an MCAS runaway was not recoverable (without the manual wheel and roller coaster procedure) if not recognized within a few seconds (exact time determined by how much authority manual electric trim had).


Even one full activation of MCAS wouldn't crash the plane - it would take a few cycles to get the plane to the point where it was unrecoverable over 30-40 seconds if not counteracted at all and you didn't pull back the thrust. It wasn't a case of don't recognize it within three seconds and you are dead.


The first question is can the crew counteract to MCAS? If the electrical trim movement is limited and the manual wheel does not budge, it would be difficult.

Cutting thrust increases the down pitch considerable.


The pitch down movement would be minimal at best going from say TOGO to a derated climb of say 85% thrust - and able to be offset by small added control column pressure.

This has been debated many times with 737 Captains saying the change is minimal if any - sure if you go from TOGO to 0% that might be an issue but good luck keeping it in the sky then.
 
AABusDrvr
Posts: 153
Joined: Sat Dec 03, 2016 6:48 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 2:22 pm

frmrCapCadet wrote:
So new would-be pilots put themselves in horrible debt and years of low wages often with terrible schedules flying small planes until they get into a seat of a mainline airline. This may not describe the European situation. Then they become computer managers and never really fly again unless a disaster happens - at which point they suddenly need to become great aviators. This is somewhat an unfair exaggeration. But:

Airbus, Boeing, the NTSB and I hope the FAA (and likely European equivalents) are thinking pilot training and skills are not as high as they should be. So what will change? AABusDriver - your post could be seen as saying the status quo is enough. What changes do you see needed?



I'm not saying the status quo will be enough. My point about small aircraft proficiency training was that because it's expensive, the airlines will never voluntarily go along with it. And it would be a hard sell with the pilots. No one I know, myself included wants to spend any more time away from home for the company, than we do now. Especially for training.

I think there will have to be global standards and requirements for entry, and training in the future, and better harmonization of regulations and oversight, at all levels.

In the US at least, we still don't have any problem finding qualified, experienced pilots, at the major level at least. I just read the average new hire first officer at the US majors has 5,000 hours total time, with 2,000 hours pilot in command in turbine airplanes. But it's coming, it's just a matter of time.

And just a personal observation about many of the new regional pilots I've met over the last few years. Many of these young men and women don't want to be pilots, they want to be AIRLINE PILOTS. They are laser focused on an airline job, and all that pesky training is just something they have to put up with to get there. And honestly, I don't think many of them really enjoy flying that much, or they don't act like it. To this guy, who never really wanted to be an airline pilot, I find that interesting.
 
ubeema
Posts: 410
Joined: Thu Aug 23, 2012 3:48 am

Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 2:34 pm

NTSB Issues 7 Safety Recommendations to FAA related to Ongoing Lion Air, Ethiopian Airlines Crash Investigations.

News release: https://www.ntsb.gov/news/press-release ... 90926.aspx

Recommendation report 19-01: https://go.usa.gov/xVv7Pv

Fair use extract:
The seven recommendations issued to the FAA urge action in three areas to improve flight safety:

#Ensure system safety assessments for the 737 MAX (and other transport-category airplanes) that used certain assumptions about pilot response to uncommanded flight control inputs, consider the effect of alerts and indications on pilot response and address any gaps in design, procedures, and/or training.

#Develop and incorporate the use of robust tools and methods for validating assumptions about pilot response to airplane failures as part of design certification.

#Incorporate system diagnostic tools to improve the prioritization of and more clearly present failure indications to pilots to improve the timeliness and effectiveness of their response.
 
User avatar
par13del
Posts: 10337
Joined: Sun Dec 18, 2005 9:14 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 2:50 pm

frmrCapCadet wrote:
So new would-be pilots put themselves in horrible debt and years of low wages often with terrible schedules flying small planes until they get into a seat of a mainline airline. This may not describe the European situation. Then they become computer managers and never really fly again unless a disaster happens - at which point they suddenly need to become great aviators. This is somewhat an unfair exaggeration. But:

I would say this is the heart of the problem, take as an example the last two major crashes that we say was mostly pilot error (AF and OZ), was it their lack of flying skills that led to the crashes or their lack of full understanding of the machines they were operating?
In both threads on this site we had pilots and defenders of both OEM' site numerous instrument displays that were readily available to assist and show them exactly what was taking place with the a/c, but they refused to believe in the instruments and or understand what they were indicating, will leave CRM out for simplicity.

I can see increased simulator time sessions and even increased frequency of simulator training, however, the programs probably need to be expanded to throw more items at the crew.
When an emergency does happen, pilots need to know their a/c in and out to get it to perform the actions required for safe recovery. We know for a fact that all pilots who get in the cockpit do know how to fly the a/c safely and get us to our destinations, accidents show us that when things go sideways not all pilots are at the same level in abnormal situations.
Unfortunately, we do not have a way at this time in our technological advancement to ensure that abnormal situations never occur, we can only minimize.
 
User avatar
par13del
Posts: 10337
Joined: Sun Dec 18, 2005 9:14 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 2:58 pm

ubeema wrote:
NTSB Issues 7 Safety Recommendations to FAA related to Ongoing Lion Air, Ethiopian Airlines Crash Investigations.

News release: https://www.ntsb.gov/news/press-release ... 90926.aspx

Recommendation report 19-01: https://go.usa.gov/xVv7Pv

Fair use extract:
The seven recommendations issued to the FAA urge action in three areas to improve flight safety:

#Ensure system safety assessments for the 737 MAX (and other transport-category airplanes) that used certain assumptions about pilot response to uncommanded flight control inputs, consider the effect of alerts and indications on pilot response and address any gaps in design, procedures, and/or training.

#Develop and incorporate the use of robust tools and methods for validating assumptions about pilot response to airplane failures as part of design certification.

#Incorporate system diagnostic tools to improve the prioritization of and more clearly present failure indications to pilots to improve the timeliness and effectiveness of their response.

Would be nice to know the details of the gap identified, I assume that is related to what the actual NNC's and other memory items involved in MCAS / Runaway recovery.
In general, I would have thought such general principles were already in place but may not have been vigorously enforced.
 
User avatar
PixelFlight
Posts: 1019
Joined: Thu Nov 08, 2018 11:09 pm

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 3:46 pm

ubeema wrote:
NTSB Issues 7 Safety Recommendations to FAA related to Ongoing Lion Air, Ethiopian Airlines Crash Investigations.

News release: https://www.ntsb.gov/news/press-release ... 90926.aspx

Recommendation report 19-01: https://go.usa.gov/xVv7Pv

Fair use extract:
The seven recommendations issued to the FAA urge action in three areas to improve flight safety:

#Ensure system safety assessments for the 737 MAX (and other transport-category airplanes) that used certain assumptions about pilot response to uncommanded flight control inputs, consider the effect of alerts and indications on pilot response and address any gaps in design, procedures, and/or training.

#Develop and incorporate the use of robust tools and methods for validating assumptions about pilot response to airplane failures as part of design certification.

#Incorporate system diagnostic tools to improve the prioritization of and more clearly present failure indications to pilots to improve the timeliness and effectiveness of their response.
:checkmark: :thumbsup:
Many thanks for that document.

I found this link more reliable:
https://www.ntsb.gov/investigations/AccidentReports/Reports/ASR1901.pdf

:hissyfit:
:point: Every contributors here should read carefully that document.
:stirthepot: 737-8 MAX: "For all speeds higher than 220 Kts and trim set at a value of 2.5 units, the difficulity level of turning the manual trim wheel was level A (trim wheel not movable)." :stirthepot:
 
morrisond
Posts: 2736
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 3:49 pm

par13del wrote:
ubeema wrote:
NTSB Issues 7 Safety Recommendations to FAA related to Ongoing Lion Air, Ethiopian Airlines Crash Investigations.

News release: https://www.ntsb.gov/news/press-release ... 90926.aspx

Recommendation report 19-01: https://go.usa.gov/xVv7Pv

Fair use extract:
The seven recommendations issued to the FAA urge action in three areas to improve flight safety:

#Ensure system safety assessments for the 737 MAX (and other transport-category airplanes) that used certain assumptions about pilot response to uncommanded flight control inputs, consider the effect of alerts and indications on pilot response and address any gaps in design, procedures, and/or training.

#Develop and incorporate the use of robust tools and methods for validating assumptions about pilot response to airplane failures as part of design certification.

#Incorporate system diagnostic tools to improve the prioritization of and more clearly present failure indications to pilots to improve the timeliness and effectiveness of their response.

Would be nice to know the details of the gap identified, I assume that is related to what the actual NNC's and other memory items involved in MCAS / Runaway recovery.
In general, I would have thought such general principles were already in place but may not have been vigorously enforced.


The NTSB report is interesting. It seems to be calling for simplifying all the Various Cockpit warnings in emergency situations by adding more specific warnings that tell the pilots exactly what is wrong. They mentioned this for all commercial manufacturers - Not just Boeing - mentioning AF447 and Airbus as well.

This is a noble goal - however you will never be able to design a system that can perfectly diagnose every failure and you are adding more complexity to the systems.

Although I think they should go down this route - this does not obviate the need for a renewed focus on when you are faced with a problem turn the Nannies off and get control of the plane - pitch and power - so you have time to diagnose what is going wrong and if you can't figure it out - fly it like it's a Cessna to the closest suitable airport.

Put a big red button in every aircraft that disconnects HAL at the first sign of trouble.
 
airtechy
Posts: 763
Joined: Sun Dec 24, 2006 7:35 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 4:22 pm

I've often wondered if the airlines could use ferry flights to reacquaint pilots in manually flying the airplane rather than engaging the autopilot at 500 ft. The fuel is burned and the pilots paid anyway. Plus, there are no passengers to worry about. Might even be an opportunity for them to become friends with the manual trim wheel. :stirthepot:

Jim
 
kalvado
Posts: 2856
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 4:37 pm

morrisond wrote:
par13del wrote:
ubeema wrote:
NTSB Issues 7 Safety Recommendations to FAA related to Ongoing Lion Air, Ethiopian Airlines Crash Investigations.

News release: https://www.ntsb.gov/news/press-release ... 90926.aspx

Recommendation report 19-01: https://go.usa.gov/xVv7Pv

Fair use extract:

Would be nice to know the details of the gap identified, I assume that is related to what the actual NNC's and other memory items involved in MCAS / Runaway recovery.
In general, I would have thought such general principles were already in place but may not have been vigorously enforced.


The NTSB report is interesting. It seems to be calling for simplifying all the Various Cockpit warnings in emergency situations by adding more specific warnings that tell the pilots exactly what is wrong. They mentioned this for all commercial manufacturers - Not just Boeing - mentioning AF447 and Airbus as well.

This is a noble goal - however you will never be able to design a system that can perfectly diagnose every failure and you are adding more complexity to the systems.

Although I think they should go down this route - this does not obviate the need for a renewed focus on when you are faced with a problem turn the Nannies off and get control of the plane - pitch and power - so you have time to diagnose what is going wrong and if you can't figure it out - fly it like it's a Cessna to the closest suitable airport.

Put a big red button in every aircraft that disconnects HAL at the first sign of trouble.

Goal of MCAS is to do exactly the opposite - to keep HAL in the loop even after the red button is pressed... And MCAS failure prevented flying pitch-and-power.
I am glad you finally start seing these problems!
 
ubeema
Posts: 410
Joined: Thu Aug 23, 2012 3:48 am

Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 4:49 pm

par13del wrote:
ubeema wrote:
NTSB Issues 7 Safety Recommendations to FAA related to Ongoing Lion Air, Ethiopian Airlines Crash Investigations.

Would be nice to know the details of the gap identified, I assume that is related to what the actual NNC's and other memory items involved in MCAS / Runaway recovery.
In general, I would have thought such general principles were already in place but may not have been vigorously enforced.

In page 5 of this report NTSB found that Boeing functional hazard assessment did not simulate impact of MCAS + erroneous high AOA and the consequences on work load. Instead Boeing simulated MCAS + AND and expected immediate pilot response.
Last edited by ubeema on Thu Sep 26, 2019 4:49 pm, edited 3 times in total.
 
XRAYretired
Posts: 870
Joined: Fri Mar 15, 2019 11:21 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 4:51 pm

morrisond wrote:
mjoelnir wrote:
morrisond wrote:

Even one full activation of MCAS wouldn't crash the plane - it would take a few cycles to get the plane to the point where it was unrecoverable over 30-40 seconds if not counteracted at all and you didn't pull back the thrust. It wasn't a case of don't recognize it within three seconds and you are dead.


The first question is can the crew counteract to MCAS? If the electrical trim movement is limited and the manual wheel does not budge, it would be difficult.

Cutting thrust increases the down pitch considerable.


The pitch down movement would be minimal at best going from say TOGO to a derated climb of say 85% thrust - and able to be offset by small added control column pressure.

This has been debated many times with 737 Captains saying the change is minimal if any - sure if you go from TOGO to 0% that might be an issue but good luck keeping it in the sky then.

Rather pointless rehearsal of the same stuff as usual. At the point in the ET302 flight, with MCAS diagnosed, the only likely recourse would be rollercoaster - nose down with 'DONT SINK' as your background music. Back to the start of this chain.

Ho hum.
 
morrisond
Posts: 2736
Joined: Thu Jan 07, 2010 12:22 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 4:53 pm

kalvado wrote:
morrisond wrote:
par13del wrote:
Would be nice to know the details of the gap identified, I assume that is related to what the actual NNC's and other memory items involved in MCAS / Runaway recovery.
In general, I would have thought such general principles were already in place but may not have been vigorously enforced.


The NTSB report is interesting. It seems to be calling for simplifying all the Various Cockpit warnings in emergency situations by adding more specific warnings that tell the pilots exactly what is wrong. They mentioned this for all commercial manufacturers - Not just Boeing - mentioning AF447 and Airbus as well.

This is a noble goal - however you will never be able to design a system that can perfectly diagnose every failure and you are adding more complexity to the systems.

Although I think they should go down this route - this does not obviate the need for a renewed focus on when you are faced with a problem turn the Nannies off and get control of the plane - pitch and power - so you have time to diagnose what is going wrong and if you can't figure it out - fly it like it's a Cessna to the closest suitable airport.

Put a big red button in every aircraft that disconnects HAL at the first sign of trouble.

Goal of MCAS is to do exactly the opposite - to keep HAL in the loop even after the red button is pressed... And MCAS failure prevented flying pitch-and-power.
I am glad you finally start seing these problems!


Umh No - The equivalent in MCAS would be to turn off the Electric Trim and use manual thrust and manual trim and the control column. How did MCAS prevent the Pilots from using the manual controls if they had choosen to do so?
 
kalvado
Posts: 2856
Joined: Wed Mar 01, 2006 4:29 am

Re: Boeing 737MAX Grounded Worldwide Q3 2019

Thu Sep 26, 2019 4:57 pm

morrisond wrote:
kalvado wrote:
morrisond wrote:

The NTSB report is interesting. It seems to be calling for simplifying all the Various Cockpit warnings in emergency situations by adding more specific warnings that tell the pilots exactly what is wrong. They mentioned this for all commercial manufacturers - Not just Boeing - mentioning AF447 and Airbus as well.

This is a noble goal - however you will never be able to design a system that can perfectly diagnose every failure and you are adding more complexity to the systems.

Although I think they should go down this route - this does not obviate the need for a renewed focus on when you are faced with a problem turn the Nannies off and get control of the plane - pitch and power - so you have time to diagnose what is going wrong and if you can't figure it out - fly it like it's a Cessna to the closest suitable airport.

Put a big red button in every aircraft that disconnects HAL at the first sign of trouble.

Goal of MCAS is to do exactly the opposite - to keep HAL in the loop even after the red button is pressed... And MCAS failure prevented flying pitch-and-power.
I am glad you finally start seing these problems!


Umh No - The equivalent in MCAS would be to turn off the Electric Trim and use manual thrust and manual trim and the control column. How did MCAS prevent the Pilots from using the manual controls if they had choosen to do so?

So there is automatic mode; there is manual operation - yoke and thrust lever; there is manual-manual operation, with actuators off. Should there also be a manual-manual-manual operation when pilots stick palms out of the window and use those as control surfaces?

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos