MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
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US Regulators Allowed Boeing 737 Max to Keep Flying After First Crash Despite FAA Analysis Predicting More
Last edited by OldnGrounded; 11th Dec 2019 at 21:21.
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So in November Boeing stated ”900+ test and production flights with new software totaling 1700+ hours".
Now we're hearing "Boeing told attendees the company has flown 1,850 flight hours with the software updates".
Note that in the Nov announcement (1700+ hours) it was test and PRODUCTION flights. Also, it was "with new software" or "the software updates", but no specifics mentioned as to what softwares were updated in those flights.
Does it count if the coffee machine was updated? Inflight entertainment system updated with new movie releases? Sounds like a software update...
I'm guessing that out of the 900+ flights, 800 or so account for ferrying grounded planes to storage.
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This whole saga just keeps getting worse and worse. 18 months ago you’d think it incredible.
I sincerely hope Boeing comes out of this better, with a renewed focus on engineering a safety. Airbus need the competition.
I sincerely hope Boeing comes out of this better, with a renewed focus on engineering a safety. Airbus need the competition.
Interesting to note the PR judo going on here, world class in that department at least. Boeing announces that the regulators will approve the fix by December, a timeline that could not legally have been based on anything other than hope. (The implication to the stockholders was that they had an inside line to the FAA.) The FAA denied that there was any such timeline. Now Boeing is blaming the potential revenue hit on "delays by regulators." Nicely done, Boeing PR.
As of the 11 December 2019 Boeing are still to provide requested information.
Part of Kiefer's testimony.
During these meetings, which included multiple online conferences and two face-to-face meetings at Boeing, our team had the full cooperation of the Boeing engineering and flight test staff as well as good participation from the avionics sub-contractor. After these meetings, briefings and demonstrations the team gathered to assemble our findings and recommendations. Some of these we have determined are necessary before returning the aircraft to service. These recommendations/action items are being actively tracked internally to the TAB and with Boeing and the FAA. All recommendations that the team made for return to service have either been addressed and closed or are presently in work. The TAB is still working with Boeing to accept products to close the remaining action items. Once all of this work is complete the TAB will present a final report to the FAA.
The TAB still has work to do to complete our assessment of the changes to the B737 MAX systems as we are awaiting more information on the development assurance, testing of the software, final safety assessments and final training for aircrew.
https://transportation.house.gov/imo...0Testimony.pdf
Part of Kiefer's testimony.
During these meetings, which included multiple online conferences and two face-to-face meetings at Boeing, our team had the full cooperation of the Boeing engineering and flight test staff as well as good participation from the avionics sub-contractor. After these meetings, briefings and demonstrations the team gathered to assemble our findings and recommendations. Some of these we have determined are necessary before returning the aircraft to service. These recommendations/action items are being actively tracked internally to the TAB and with Boeing and the FAA. All recommendations that the team made for return to service have either been addressed and closed or are presently in work. The TAB is still working with Boeing to accept products to close the remaining action items. Once all of this work is complete the TAB will present a final report to the FAA.
The TAB still has work to do to complete our assessment of the changes to the B737 MAX systems as we are awaiting more information on the development assurance, testing of the software, final safety assessments and final training for aircrew.
https://transportation.house.gov/imo...0Testimony.pdf
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Seems like the Boeing event went down well with this reporter – see the “conclusion” below.
Translation from French by Google is unmodified here....
“Conclusion of these two days
If we consider that all the information provided to us is reliable (I dare not imagine that Boeing can try to lie hide anything), then I think we were convinced. The aircraft is ultimately not unstable and the presence of the MCAS desirable. The initial error is repaired and the pilots present, first concerned,confirmed their confidence in the plane and their willingness to take back orders at the earliest (I made an interview with the president of a Chinese pilots association , I am waiting for the validation of my images in the simulator to share them at the same time).”
Translation from French by Google is unmodified here....
“Conclusion of these two days
If we consider that all the information provided to us is reliable (I dare not imagine that Boeing can try to lie hide anything), then I think we were convinced. The aircraft is ultimately not unstable and the presence of the MCAS desirable. The initial error is repaired and the pilots present, first concerned,confirmed their confidence in the plane and their willingness to take back orders at the earliest (I made an interview with the president of a Chinese pilots association , I am waiting for the validation of my images in the simulator to share them at the same time).”
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* Or so we're told. Some of the skeptical among us** are still stubbornly wondering about that stability thing.
** To include the Joint Authorities Technical Review
Last edited by OldnGrounded; 12th Dec 2019 at 13:39. Reason: Typo
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Re: flight hours: Boeing had stated they were flight testing updated software prior to the second crash, had they not? So maybe they are counting some of that time?
Not saying they should; on the contrary, they don't get to start counting final fix flight test hours until they have a final fix, with no further revisions, approved by all global authorities. That final rev? Yeah, count those hours.
More relevant would be the number of times they pushed into the corners in question, with minimum acceptance trained pilots at the controls, and got MCAS to activate, plus actual failure modes activated in flight, with the same experience level pilots. Do that x# of times, simulating 20 years worth of the global fleet experiencing those corners/failures, and I'll even accept more experienced pilots for the later tests, approximating the maturation of the global experience levels.
So what we talking about, fleet wise? Several hundred envelope corner excursions, and thousands of single AoA vane failures? Plus a couple dozen 2x vane failures, plus all the added related equipment/computer failures? More? Less? By orders of magnitude?
Whatever it is, add it up. Fly them all, with at least nominal surprise (OK, test pilots will know something will happen in testing, just not what and when). You're asking us to fly it all over time; OK, you first, Boeing.
Not saying they should; on the contrary, they don't get to start counting final fix flight test hours until they have a final fix, with no further revisions, approved by all global authorities. That final rev? Yeah, count those hours.
More relevant would be the number of times they pushed into the corners in question, with minimum acceptance trained pilots at the controls, and got MCAS to activate, plus actual failure modes activated in flight, with the same experience level pilots. Do that x# of times, simulating 20 years worth of the global fleet experiencing those corners/failures, and I'll even accept more experienced pilots for the later tests, approximating the maturation of the global experience levels.
So what we talking about, fleet wise? Several hundred envelope corner excursions, and thousands of single AoA vane failures? Plus a couple dozen 2x vane failures, plus all the added related equipment/computer failures? More? Less? By orders of magnitude?
Whatever it is, add it up. Fly them all, with at least nominal surprise (OK, test pilots will know something will happen in testing, just not what and when). You're asking us to fly it all over time; OK, you first, Boeing.
Last edited by DieselOx; 12th Dec 2019 at 04:47.
Seems like the Boeing event went down well with this reporter – see the “conclusion” below.
Translation from French by Google is unmodified here....
“Conclusion of these two days
If we consider that all the information provided to us is reliable (I dare not imagine that Boeing can try to lie hide anything), then I think we were convinced. The aircraft is ultimately not unstable and the presence of the MCAS desirable. The initial error is repaired and the pilots present, first concerned,confirmed their confidence in the plane and their willingness to take back orders at the earliest (I made an interview with the president of a Chinese pilots association , I am waiting for the validation of my images in the simulator to share them at the same time).”
Translation from French by Google is unmodified here....
“Conclusion of these two days
If we consider that all the information provided to us is reliable (I dare not imagine that Boeing can try to lie hide anything), then I think we were convinced. The aircraft is ultimately not unstable and the presence of the MCAS desirable. The initial error is repaired and the pilots present, first concerned,confirmed their confidence in the plane and their willingness to take back orders at the earliest (I made an interview with the president of a Chinese pilots association , I am waiting for the validation of my images in the simulator to share them at the same time).”
I do not know how/why this ex-military pilot was invited, probably only because he is the manager of the Centre de Traitement de la Peur de l'Avion (Airplane Fear Treatment Centre); it reinforces that this event was only a PR one.
In any case, this gentleman did not follow too much the B737Max/MCAS matter before his visit; in the comments below his paper (automatic translation and my emphasizing):
"- the origin of the MCAS, which seemed new to me, has in fact been recurrent for months, it has simply never been covered in the media (and it is therefore not a communication invention imagined for our trip)"
"- the question of the aircraft's nose-up tendency is also raised by Boeing. It is not clear whether this is an ANU tendency of the aircraft in these particular flight conditions, or a lightness of the control column that could cause pilots to pull too much."
So, probably better to wait for the conclusions of a non-PR event, written by someone knowing....
.
Federal Aviation Administration chief Stephen Dickson said that the plane, which has been grounded worldwide since March, will not be certified to fly this year, dashing Boeing’s hopes of getting the popular family of planes back in the air in 2019.
“If you do the math, it’s going to extend into 2020,” Dickson told CNBC Wednesday
“If you do the math, it’s going to extend into 2020,” Dickson told CNBC Wednesday
Simples - 30 days minimum after final submission of fix for re-certification.
Given Boeing as of 11 December have not supplied the required information requested, including pilot training requirements.
Maths suggests any time in 2019 is not possible ( there is not 30 days left in 2019!)
See my post just above what is outstanding for Boeing to supply before a recommendation can be given to the regulator, then the 30 day (minimum) count can start.
Is there any draft document available about the actual changes finally intended to be submitted by Boeing? If we are as close as claimed why is there no detailed info available?
There are four main changes to the B737 MAX flight control system software that have been developed to prevent future accidents like the ones that happened with the Lion Air and Ethiopian Air flights. They include the following:
1. Angle of Attack (AoA) comparison – an addition to MCAS that will now compare readings from both angle of attack sensors on the aircraft. If there is a difference of more than 5.5 degrees the speed trim system will be disabled. Also included in this change is something known as a “midvalue select” which uses data from both sensors together to create a third input that will help to filter out any AOA signal oscillatory failures or spurious sensor failures. This modification will prevent MCAS from commanding nose down trim when a single AoA sensor reports a false AoA as it happened in the two accident flights.
2. MCAS resynchronization – this change will account for manual electric trim inputs made by the pilot while MCAS is activating. It will track whatever input the pilot makes and return the pitch trim to that setting when MCAS retrims back to normal.
3. Stab trim command limit – is an addition that will limit the maximum nose down trim that the automatic flight control system can command to prevent the pitch trim from reaching an uncontrollable situation.
4. FCC monitors – software monitors have been added to the flight control computers that will cross check pitch trim commands against each other. If a difference is detected by these monitors the automatic trim functions are disabled. This protection helps prevent erroneous trim commands from a myriad of causes that could occur in the automatic flight control system.
turbidus,
No idea, but it was taught on the 707
No idea, but it was taught on the 707
Now it is a box that is ticked - and admitted as not correct in some simulations in areas for many years.
But the box still gets ticked.
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Not only that, this statement was made to the Securities & Exchange Commission. Now the SEC are no fools, and if they determine that Boeing has been peddling nonsense about service re-entry and resumption of sales revenue, both to investors and now to them, that will not go down well.
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Assumptions all over, but... imho re-entry into service could be achieved by the following:
How these changes are made is likely to remain confidential until approved to ensure the impartiality and integrity of design changes.
Time will tell, think it won't be much longer as the earliest time it takes for these stages to complete is coming towards fruition soon.
- ensure MCAS can only activate if both sensors agree;
- ensure the original cutout which pilots relied on for many years (column cutout) is instated for MCAS cutout
How these changes are made is likely to remain confidential until approved to ensure the impartiality and integrity of design changes.
Time will tell, think it won't be much longer as the earliest time it takes for these stages to complete is coming towards fruition soon.
Assumptions all over, but... imho re-entry into service could be achieved by the following:
How these changes are made is likely to remain confidential until approved to ensure the impartiality and integrity of design changes.
Time will tell, think it won't be much longer as the earliest time it takes for these stages to complete is coming towards fruition soon.
- ensure MCAS can only activate if both sensors agree;
- ensure the original cutout which pilots relied on for many years (column cutout) is instated for MCAS cutout
How these changes are made is likely to remain confidential until approved to ensure the impartiality and integrity of design changes.
Time will tell, think it won't be much longer as the earliest time it takes for these stages to complete is coming towards fruition soon.
If 2 is required then another solution to the flight instability (which is not instability) will be needed
What's missing from both public accounts of the Seattle show: an explanation of the second, more dangerous stage of the MCAS development, when its authority was considerably increased. Why was that thought to be needed at the time? Why is it now OK for MCAS to be less tenacious?
