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MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures

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MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures

Old 23rd Aug 2019, 11:02
  #2001 (permalink)  
 
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Originally Posted by PerPurumTonantes View Post
They haven't been reading their PPRuNe

​​​​​​It was pointed out some time ago that if they aimed at the "average" pilot, that may leave 50% of pilots unable to cope.

They need the worst case pilots, the least able ones. Which leaves an interesting question- how do you get hold of them?

"Hey you've been specially selected for this brand new testing event at the FAA!"
"Is that because of my outstanding skills and experience? "
​​​​​​" errr... "
I guess at some point we will arrive at Schrodinger's pilot.

He is bad enough to test the system, but testing the system makes him a better pilot.

At which point is his analysis still valid?
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Old 23rd Aug 2019, 11:13
  #2002 (permalink)  
 
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How is coupling the 2 FCC's together going to work? Doesnt this take out redundancy?
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Old 23rd Aug 2019, 11:39
  #2003 (permalink)  
 
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Originally Posted by Hawker400 View Post
I guess at some point we will arrive at Schrodinger's pilot.

He is bad enough to test the system, but testing the system makes him a better pilot.

At which point is his analysis still valid?
That's not really Schroedinger - that would be a pilot with both extreme skills and no skills at all who'd only crystalise into one state when faced with an emergency

I think you have Heissenberg down pat, though - no observation is perfectly accurate as the observation itself will change the observed.
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Old 23rd Aug 2019, 12:12
  #2004 (permalink)  
 
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Originally Posted by Maninthebar View Post

- no observation is perfectly accurate as the observation itself will change the observed.
Aside from which, this is probably the most widely known about topic in recent aviation history. Not only will almost all 737 MAX pilots be aware of what is likely to face them in the sim, but will have read about it and most likely have all memory items associated with it, off pat.

If this sim testing did not produce a 100% successful outcome rate, I would be very, very worried regardless of the calibre of pilots selected.

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Old 23rd Aug 2019, 12:32
  #2005 (permalink)  
 
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Originally Posted by PerPurumTonantes View Post
They haven't been reading their PPRuNe

​​​​​​It was pointed out some time ago that if they aimed at the "average" pilot, that may leave 50% of pilots unable to cope.

They need the worst case pilots, the least able ones. Which leaves an interesting question- how do you get hold of them?

"Hey you've been specially selected for this brand new testing event at the FAA!"
"Is that because of my outstanding skills and experience? "
​​​​​​" errr... "
Get a pilot with no experience on the 737 setup the sim to be on the same path as the 2 incident flights and give them the procedure to recover , as on the incident flights they didnt touch throttles or anything elseb pulling back on yoke and trim related switches.

Last edited by maxxer; 23rd Aug 2019 at 12:34. Reason: Typos
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Old 23rd Aug 2019, 13:42
  #2006 (permalink)  
 
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Originally Posted by Speed of Sound View Post


Aside from which, this is probably the most widely known about topic in recent aviation history. Not only will almost all 737 MAX pilots be aware of what is likely to face them in the sim, but will have read about it and most likely have all memory items associated with it, off pat.

If this sim testing did not produce a 100% successful outcome rate, I would be very, very worried regardless of the calibre of pilots selected.

One can hope that the Lion air and Ethiopian investigators did such testing early on before it became widely known and discussed.
In fact the Ethiopian accident suggests that the crew was not fully aware and ready to pounce on MCAS, although in that case partial knowledge may have been deadly if it led to disabling electric trim before achieving neutral trim.
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Old 23rd Aug 2019, 15:28
  #2007 (permalink)  
 
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There are lots of ways that testers can manipulate humans to degrade their performance, way way back my dad designed this sort of stuff for Army experiments. The best way is to have the subject really tired, that is about the same as getting them drunk. Then play loud startling noises at them while they try to perform the task. Flashing lights are also good. If you wanted to be really cruel you could add some physical discomfort, maybe have them hold some object that unexpectedly starts to vibrate...
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Old 23rd Aug 2019, 19:19
  #2008 (permalink)  
 
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Originally Posted by Water pilot View Post

There are lots of ways that testers can manipulate humans to degrade their performance, way way back my dad designed this sort of stuff for Army experiments.
The problem isn’t the absence of ‘startle factor’, it is the amount of pre-knowledge of the subject that will make this sim testing difficult to draw meaningful conclusions from.
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Old 23rd Aug 2019, 20:03
  #2009 (permalink)  
 
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Originally Posted by Speed of Sound View Post


The problem isn’t the absence of ‘startle factor’, it is the amount of pre-knowledge of the subject that will make this sim testing difficult to draw meaningful conclusions from.
Very true. That makes it even more interesting that in the SIM scenarios after the 2nd crash even one of the Boeing or FAA test pilots wasn't able to save the aircraft.
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Old 23rd Aug 2019, 21:09
  #2010 (permalink)  
 
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Originally Posted by jantar99 View Post
Technically, fuel molecules have not been synthesized at the refinery, but separated from different kinds of molecules.
I'd suggest that you research what a hydrocracker is, what it does, and what percentage of kerosene is straight-run distilled vs what percentage is cracked. A hydrocracker does not simply separate crude oil into it's various weight fractions. It synthesizes short-chain hydrocarbons such as kerosene from longer chain hydrocarbons. It creates new molecules from older molecules. For bonus points, look into the sulphur content of straight-run kerosene vs cracked kerosene, and compare that to the specification limits for Jet-A, and you will understand why Jet-A is mostly produced from cracked kerosene feedstock.

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Old 23rd Aug 2019, 23:14
  #2011 (permalink)  
 
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Todays news says the FAA is asking for MAX pilots from around the world to sim test the new software fix.,..not just Sr Pilots...

https://www.yahoo.com/finance/news/u...181043724.html

Curious, I dont see any Boeing response to the some of the EASA requirements for the MAX cert, specifically the manual trim wheel and AP issues...
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Old 24th Aug 2019, 00:06
  #2012 (permalink)  
 
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Originally Posted by Smythe View Post
Todays news says the FAA is asking for MAX pilots from around the world to sim test the new software fix.,..not just Sr Pilots...

https://www.yahoo.com/finance/news/u...181043724.html

Curious, I dont see any Boeing response to the some of the EASA requirements for the MAX cert, specifically the manual trim wheel and AP issues...
So to be let in the sim you must have had at least one MAX flight!

But to get a front seat (for the first time) in a MAX you need 1 hour on the iPad.

FAA seems to be taking too big a steps in recent days, but other regulators seem silent.
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Old 24th Aug 2019, 00:29
  #2013 (permalink)  
 
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Given the current state of US/China trade relations, does anyone believe China will unground the MAX in lock step with the FAA?
Boeing is in the perilous position of having become a political symbol. That is not always helpful.
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Old 24th Aug 2019, 00:31
  #2014 (permalink)  
 
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Originally Posted by Zeffy View Post
https://www.seattletimes.com/busines...urn-to-flight/

quote:
FAA guidelines say that if an emergency arises on a plane flying by autopilot, the assumption is that a pilot will begin to respond within three seconds. If the plane is being flown manually, the assumption is one second. When FAA test pilots deliberately delayed their responses in a simulation in June, one of the pilots crashed the plane.
Not a pilot. FAA's assumption that during manual flight pilots will begin to respond to emergencies within one second sounds reasonable, if we take "will begin to respond" literally.

A study about reaction times for car emergency braking found that the average driver will start releasing the accelerator about one second after another vehicle starts crossing a intersection right in front of them: https://copradar.com/redlight/factors/IEA2000_ABS51.pdf

Accounting for some peculiarities of that experiment, overall I could say the initial reaction times of the car drivers were between 0.8 seconds and 1.2 seconds. That seems comparable to the assumption of the FAA.

However, the drivers needed an additional 1.8 to 2.8 seconds to completely release the accelerator, move their foot on the brake, and apply maximum braking pressure. So the total response time to the emergency was between 2.6 and 4 seconds. I computed those ranges as the average +/- the standard deviation.

Anyway, I think the initial response time is the wrong thing to focus on. I think much more important is what happens after the initial response. For example, on the Ethiopian flight, according to the preliminary report, this was the sequence of events during around the initial MCAS activation:

At 05:39:55, Autopilot disengaged,
At 05:39:57, the Captain advised again the First-Officer to request to maintain runway heading and that they are having flight control problems.
At 05:40:00 shortly after the autopilot disengaged, the FDR recorded an automatic aircraft nose down (AND) activated for 9.0 seconds and pitch trim moved from 4.60 to 2.1 units.
The climb was arrested and the aircraft descended slightly.
At 05:40:03 Ground Proximity Warning System (GPWS) “DON’T SINK” alerts occurred.
At 05:40:05, the First-Officer reported to ATC that they were unable to maintain SHALA 1A and requested runway heading which was approved by ATC.
At 05:40:06, left and right flap position reached a recorded value of 0.019 degrees which remained until the end of the recording.
The column moved aft and a positive climb was re-established during the automatic AND motion.
At 05:40:12, approximately three seconds after AND stabilizer motion ends, electric trim (from pilot activated switches on the yoke) in the Aircraft nose up (ANU) direction is recorded on the DFDR and the stabilizer moved in the ANU direction to 2.4 units.
So, according to the transcript "The column moved aft and a positive climb was re-established during the automatic AND motion.". But, looking at the DFDR traces, that's not exactly what happened. The pilot actually started moving the column aft almost immediately after the auto pilot disconnected, and a few seconds before MCAS activated. And he continued moving the column aft throughout the first MCAS AND movement, with some fluctuations. So, in my opinion, there was 0 response time, as the pilot responded to MCAS by continuing to do what he was already doing: moving the column aft. Of course, it's debatable if you consider that a response or not. I guess some could say he should have also started to apply ANU trim immediately, not 12 seconds after MCAS first activated, and that just continuing to move the column aft is not a response.

Also about: "The climb was arrested and the aircraft descended slightly." The report seems to suggest that it was caused by MCAS, but according to the DFDR traces for the altitude that's not what happened. Actually the aircraft stopped climbing and started a slight descent even before MCAS activated.

And finally "The column moved aft and a positive climb was re-established during the automatic AND motion." Well, looking at the altitude DFDR traces again, I'm not sure I agree with that either. At most you could say the pilot stopped it from descending. It only started climbing a bit after they manually applied some nose up trim, then the second MCAS activation negated that, and they only resumed climbing at a significant rate after applying a larger amount of nose up trim and using the cutout switches to prevent further MCAS activations.

Unfortunately the DFDR traces don't include the vertical speed to make this more obvious, but, unlike the Lion Air accident flight and the previous Lion Air flight, that at some point behaved like a roller coaster, with huge altitude losses, overall the Ethiopian flight was neither ascending or descending a lot before and during the two MCAS activations. The altitude trace is almost flat for that interval.

So, to conclude, I think it's much more important how the pilots responded and to understand why. Not precisely how many seconds it actually took them to respond to the emergency. It doesn't matter if the response time is one second, 0.5 seconds or 0.1 seconds, if the response is letting go of the controls and closing your eyes. And yes, unfortunately some car "drivers" do that when faced with an emergency.
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Old 24th Aug 2019, 00:44
  #2015 (permalink)  
 
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Yes, it removes any redundancy

Originally Posted by Smythe View Post
How is coupling the 2 FCC's together going to work? Doesnt this take out redundancy?
and I don‘t see any chance of EASA taking this shortcut even into consideration for any ungeounding.
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Old 24th Aug 2019, 04:22
  #2016 (permalink)  
 
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MAX is not a 21st Century aircraft

Originally Posted by silverstrata View Post
How did a single-channel MCAS ever get fitted to a 21st century aircraft?

Silver
You mistake the B737 MAX for a 21st Century aircraft.
The MAX is a aircraft grandfathered to 1960s standards, which Boeing intend to continue to manufacture until the mid- to late-2020s, and expect to still be flying in very large numbers in the 2040s

Whether or not that is a good idea is an entirely different question
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Old 24th Aug 2019, 05:48
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The B52 bomber has been in service with the USAF since 1955, with the recent upgrades it received it's expected to remain in service into the 2050s. Perhaps the mentality at Boeing is to get 100 years out of a basic airframe. Even the Russians who are renown for modernising and upgrading old designs don't expect that long.
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Old 24th Aug 2019, 07:01
  #2018 (permalink)  
 
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Originally Posted by krismiler View Post
The B52 bomber has been in service with the USAF since 1955, with the recent upgrades it received it's expected to remain in service into the 2050s. Perhaps the mentality at Boeing is to get 100 years out of a basic airframe. Even the Russians who are renown for modernising and upgrading old designs don't expect that long.
They don't have shareholders who have to be rewarded.
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Old 24th Aug 2019, 18:14
  #2019 (permalink)  
 
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Boeing 737 Max’s Certification Flight Likely to Occur in October


‎Yesterday, ‎August ‎23, ‎2019, ‏‎6:58:02 PM Canadian Aviation NewsNews provided by BNNBloomberg.ca – link to full story and updates

23 August 2019 by Julie Johnsson, Alan Levin and Richard Weiss, Bloomberg News

(Bloomberg) — The Federal Aviation Administration is likely to conduct its certification flight for Boeing Co.’s 737 Max in October, a key milestone toward returning the grounded jetliner to the skies, said people briefed on the matter.

That timing would be broadly consistent with Boeing’s estimate that the Max will return to service early in the fourth quarter, but may push the submission of a final certification package slightly beyond September, as the company previously estimated.

The U.S. planemaker is testing changes to the flight-control software architecture of its best-selling jetliner, which suffered two fatal crashes in a five-month span. Boeing engineers have almost worked their way through hundreds of queries fielded by the FAA from colleagues around the world, with few new concerns being raised at this point in the process, the people said.

The Chicago-based company is also briefing customers on its plans for unwinding an unprecedented global grounding that has already surpassed five months, with about 600 planes temporarily mothballed.

“We continue to support the FAA and global regulators on the safe return of the Max to service,” Boeing said in a statement.

The FAA is focused on ensuring that the revamped 737 Max systems meet safety requirements, and doesn’t have a timeline for returning the plane to service, according to a statement by the agency. FAA employees have already spent 110,000 hours working on the project, it said.

‘All Aspects’

“The FAA’s certification of the Boeing 737 Max is the subject of several independent reviews and investigations that will examine all aspects of the five-year effort,” the agency said. “While the agency’s certification processes are well established and have consistently produced safe aircraft designs, we welcome the scrutiny from these experts and look forward to their findings.”

There are still numerous tasks to be accomplished before Boeing can complete its submission to recertify the plane, said another person familiar with the process. The person wasn’t aware of a specific projection that the FAA test flight would occur in October, but said it was a possibility.

A certification flight with FAA test pilots is one of the final steps that must be conducted before Boeing’s submission is finalized, and based on the timing, the final paperwork may not be completed until the fourth quarter.

If the plane behaves as expected, the results become part of the package for certification. Even though FAA engineers have worked closely with Boeing for months, the agency must perform a series of checks after the submission is made before granting approval.

Another step in the process is a review by the FAA’s Flight Standardization Board, which must recommend training requirements for the plane. In April, it made a preliminary conclusion that pilots wouldn’t need simulator training before flights resume. But the body hasn’t issued its final conclusions.
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Old 25th Aug 2019, 01:05
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Originally Posted by MemberBerry View Post
Also about: "The climb was arrested and the aircraft descended slightly." The report seems to suggest that it was caused by MCAS, but according to the DFDR traces for the altitude that's not what happened. Actually the aircraft stopped climbing and started a slight descent even before MCAS activated.
The climb was arrested when flaps retracted. The climb was shallow to begin with. Look at the Reuters graphics comparing the ET302 accident flight climb profile with other flights leaving Addis Ababa and with the Lion Air 610. (Google "graphics reuters Ethiopia-airplane") The graphic shows that one other flight out of Addis Ababa had a similarly shallow departure climb and had to go around the east side of the mountain to the southeast.

Also, it looks to me like they pitched up was pretty high immediately after wheels off and then the PF forced the nose down with forward control column pressure.

As I have commented previously, I believe ET302 was over Regulated Take Off Weight. The Preliminary Report says they were below RTOW, but if you look at the weight and balance information, they assumed around 167 lbs./pax, INCLUDING carry-on bags. If you use 190 lbs./pax, they were over by around 2,000 lbs. And if that's correct, then the reason appears to be that they were ferrying fuel (to save money by not paying for it in Nairobi?). Perhaps this was standard EA practice and explains the shallow climb of one of the other flights shown in the Reuters graphic.

If they were overweight, and it affected take-off and initial climb performance, then that might explain why the crew failed to retard the throttles, even after the overspeed clackers started going off at 05:41:20 and 05:41:32.

In any event, the time required to respond to activation of MCAS, or recognition of any stab trim abnormality, appears to be irrelevant to both JT610 and ET302. Both crews may have been startled initially, but both crews maintained control of their aircraft for minutes, not seconds, and any initial delay in recognizing that there was a stab trim problem wasn't what caused the loss of the airplanes.
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