Ethiopian 737-8 MAX down. No survivors. | Page 19 | FerrariChat

Ethiopian 737-8 MAX down. No survivors.

Discussion in 'Aviation Chat' started by RWatters, Mar 10, 2019.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. jcurry

    jcurry Two Time F1 World Champ
    Silver Subscribed

    Jan 16, 2012
    21,369
    In the past
    Full Name:
    Jim
    His comments seemed to be focused on the training aspects. I think that probably bodes well for Boeing. However, as a passenger I would rather see a fix that is not so reliant on pilot training.
     
    Bob Parks likes this.
  2. F1tommy

    F1tommy F1 World Champ
    Silver Subscribed

    Dec 15, 2007
    10,254
    Chicagoland USA
    Full Name:
    Tom Tanner
    #452 F1tommy, May 23, 2019
    Last edited: May 23, 2019
    That's just the FAA saying they will get it right, THIS TIME :) Even with pilot training I think a July timetable is probably accurate. As long as the MCAS system does turn off after the first incorrect reading I would feel safe, but what tells it the reading is incorrect?? The pilot or another backup sensor? I think they said 2 sensors now.

    By the way I find it entertaining that some articles act like this could kill Boeing. With military and widebody contracts that is not a possibility. It will hurt their bottom line but the 737 has the least profit margin per unit of all their commercial aircraft.
     
  3. donv

    donv Two Time F1 World Champ
    Owner Rossa Subscribed

    Jan 5, 2002
    23,988
    Portland, Oregon
    Full Name:
    Don
    There is no fix that isn't reliant on pilot training. They're not going to redesign the entire airplane, and that's really the only other option.

    Sure, they'll improve the systems logic a bit, but there is only so much they can do.
     
  4. jcurry

    jcurry Two Time F1 World Champ
    Silver Subscribed

    Jan 16, 2012
    21,369
    In the past
    Full Name:
    Jim
    I understand that, and my statement did not present it as an absolute.
     
  5. Jeff Kennedy

    Jeff Kennedy F1 Veteran
    Owner Silver Subscribed

    Oct 16, 2007
    6,535
    Edwardsville, IL
    Full Name:
    Jeff Kennedy
    FAA: International Input Could Factor Into MAX Un-grounding
    May 24, 2019 Sean Broderick | Aviation Daily
    Comments 2

    FAA’s decision to allow the Boeing 737 MAX back into the air could be based at least in part on input from foreign regulators, though consensus will not be necessary for the U.S. agency to move forward, FAA Acting Administrator Dan Elwell said.

    Speaking to reporters following an FAA-hosted gathering of regulators from around the world May 23, Elwell confirmed that Boeing’s final application for changes to the MAX’s maneuvering characteristics augmentation system (MCAS) has not been received. Once the package is in FAA’s hands, “we will perform our final risk assessments and analysis, taking into account findings of the [Technical Advisory Board] and any information we receive from our international counterparts,” Elwell said. The TAB is a multi-agency group tasked with providing real-time feedback on Boeing’s proposed MCAS changes.

    Elwell reiterated that while consensus would likely be beneficial for public confidence, each country must make its own decision based on its own parameters, just as happened when choosing to ground the fleet following the March 10 crash of Ethiopian Airlines Flight 302.

    “Other countries have other decision-making processes,” Elwell said. "I’m not driven by other countries’ decisions. I’m driven by our process and the data that we collect.”

    Elwell declined to speculate on when FAA might lift its MAX ban. “We are going through an incredibly intensive and robust process to make the safety case to unground the MAX,” he said. "We won't unground the MAX until we've made that safety case."

    While FAA will be the first to make the move, it is not clear if any other countries will walk in lock-step with the U.S. agency. Several countries – including Canada – are expected to conduct their own reviews of Boeing’s changes, which would likely prolong the groundings.

    Transport Canada will be doing its own review of these design changes prior to accepting them on Canadian-registered aircraft by our own validation process,” Transport Canada director general of civil aviation Nicolas Robinson told reporters after the meeting. "Our review of the Max design changes, the software upgrade is already underway."

    The gathering in Fort Worth included nearly 60 representatives from 33 civil aviation agencies. Elwell said the proceedings, which ran an hour past the scheduled time to allow dialogue to continue, were “both comprehensive and constructive.” FAA faced “frank” questions from the group, but no outright criticism of decisions related to certifying the MAX, or of the U.S. being the last to ground it.

    Among the topics on the agenda was training. Some countries have been vocal about the need to put pilots in MAX simulators as a condition to getting the 370-aircraft fleet back into service. Elwell said nobody in the meeting “stood up and said we need to have simulator training" as part of a still-to-be-finalized package of baseline training. A draft of the training standards did not recommend simulator training, but a review of the final package could change FAA’s view. “Nothing is final until it’s final,” Elwell said.

    Boeing said it is working on some FAA requests and then plans to wrap up certification testing. "Once we have addressed the information requests from the FAA, we will be ready to schedule a certification test flight and submit final certification documentation,” the manufacturer said.

    Looking at the bigger picture, Elwell said that it is too early to glean any lessons learned from the series of FAA certification process reviews that are underway. “I can’t predict what’s going to be recommended,” Elwell said. "I just know that when qualified experts look at our processes and give us recommendations, it helps us.”

    The MAX fleet was grounded when regulators detected similarities in the flight profiles of both the Ethiopian and Lion Air accidents. The aircraft’s MCAS flight control law was quickly identified as a contributor to both accident sequences. Boeing’s changes focus on making the MCAS more reliable and easier for pilots to over-ride if necessary. —Sean Broderick, [email protected]
     
  6. Nurburgringer

    Nurburgringer F1 World Champ

    Jan 3, 2009
    11,031
    Texass
    Why can't the MCAS simply turn off once the pilot's controls contradict it's decision to push the nose down? Like tapping the brakes immediately disengages cruise control on your car. I understand that the plane will try to climb under heavy throttle due to the location of it's big, new turbines but I can't imagine why it shouldn't automatically turn off when the pilots are pulling back on the yoke with all their might while the effin thing fights them time after time.

    It's crazy that Boeing shipped planes with MCAS activation depending on a single AOA instrument (if comparing info from 2 or more AoA sensors was so expensive, at least they could have compared the single AoA signal to climb-rate data from GPS for free), but even more egregious is putting more trust in that MCAS system than the Pilot's inputs.
     
    showme1946 and jcurry like this.
  7. jcurry

    jcurry Two Time F1 World Champ
    Silver Subscribed

    Jan 16, 2012
    21,369
    In the past
    Full Name:
    Jim
    Getting it to turn off is the easy part. How to decide when it will reactivate is more difficult, which played a part in the accidents.
     
    Nurburgringer likes this.
  8. Nurburgringer

    Nurburgringer F1 World Champ

    Jan 3, 2009
    11,031
    Texass
    As to when MCAS would be reactivated after it'd been overruled by (emphatic) pilot inputs, I'm sure everyone on the Lion Air and Ethiopian 737's would have been ok with "never". ;)
     
    showme1946 and jcurry like this.
  9. Nurburgringer

    Nurburgringer F1 World Champ

    Jan 3, 2009
    11,031
    Texass
    #460 Nurburgringer, May 24, 2019
    Last edited: May 24, 2019
    this may have already been posted, but here's a statement on April 17th by Boeing on the "upgrades" being made to MCAS.
    Point 3 addresses pilot inputs vs MCAS pitch control. Interesting that they don't say that MCAS is automatically deactivated by pilot column input, only that pilots can (now) always "counteract" MCAS stab commands purely through column inputs vs multiple steps flipping switches/trim wheels/etc previously necessary to "override MCAS".

    Edit: Obviously much smarter people than me came up with this, but doesn't 5.5 degree allowable disagreement between AoA sensors seem like a lot? Sure maybe in very short transient conditions 5 degree disagreement might be acceptable, but I think I'd want the sensor readings to be closer that that over time.

    https://www.boeing.com/commercial/737max/737-max-software-updates.page

    The additional layers of protection include:

    • Flight control system will now compare inputs from both AOA sensors. If the sensors disagree by 5.5 degrees or more with the flaps retracted, MCAS will not activate. An indicator on the flight deck display will alert the pilots.
    • If MCAS is activated in non-normal conditions, it will only provide one input for each elevated AOA event. There are no known or envisioned failure conditions where MCAS will provide multiple inputs.
    • MCAS can never command more stabilizer input than can be counteracted by the flight crew pulling back on the column. The pilots will continue to always have the ability to override MCAS and manually control the airplane.
     
    Ferrari 308 GTB likes this.
  10. F1tommy

    F1tommy F1 World Champ
    Silver Subscribed

    Dec 15, 2007
    10,254
    Chicagoland USA
    Full Name:
    Tom Tanner
    Another picture of the parking lot. I wonder if those Jet Airways aircraft will ever make it to the airline since they are in big trouble. Please move your car or it will be towed for 737 parking :)
     

    Attached Files:

  11. atomicskiracer

    atomicskiracer Formula 3

    Mar 30, 2005
    1,708
    Full Name:
    Ryan
    That is a lot of $$$ sitting around.
     
  12. jcurry

    jcurry Two Time F1 World Champ
    Silver Subscribed

    Jan 16, 2012
    21,369
    In the past
    Full Name:
    Jim
  13. teak360

    teak360 F1 World Champ

    Nov 3, 2003
    10,065
    Boulder, CO
    Full Name:
    Scott
    Juan has good info:

     
    FERRARI-TECH likes this.
  14. BMW.SauberF1Team

    BMW.SauberF1Team F1 World Champ

    Dec 4, 2004
    14,244
    Pretty impressive those regular car parking lots can support those planes...asphalt car parking lots are usually pretty thin. Maybe they planned ahead for such a situation when paving it. I'm not sure what the soil is like, but probably not firm like it is in AZ with all the graveyard storage on dirt (hence flash floods rather than going into the ground quickly when it rains).
     
  15. Nurburgringer

    Nurburgringer F1 World Champ

    Jan 3, 2009
    11,031
    Texass
    #466 Nurburgringer, Jun 1, 2019
    Last edited: Jun 1, 2019
    Dad just sent me a very interesting NY Times article today with a lot of info I hadn't read before: https://www.nytimes.com/2019/06/01/business/boeing-737-max-crash.html?ref=headline&nl=top-stories

    So from when the original MCAS idea was hatched to when airlines started flying the 737 Max, Boeing:
    - vastly increased the flight envelope where MCAS could activate
    - eliminated all signal redundancy feeding MCAS activation (original system compared data from the AoA with that from a g-meter, which apparently didn't work at the lower speeds the plane was found to also be less than stable at)
    - didn't properly test the system (i.e. what happens if the single AoA sensor provides bad info, for whatever reason)
    - greatly increased the speed at which MCAS moved the tail's angle
    - underestimated the probability of erroneous triggering of MCAS
    - successfully lobbied the FAA (which only knew of an earlier, much less intrusive version of the system) to remove any mention of MCAS from the pilot's manual

    Ouch.
     
  16. Nurburgringer

    Nurburgringer F1 World Champ

    Jan 3, 2009
    11,031
    Texass
    #467 Nurburgringer, Jun 1, 2019
    Last edited: Jun 1, 2019
    Some disagreement on why MCAS was even conceived. Juan says it was never intended to prevent stalls or enhance stability ("the 737 is inherently stable on it's own. Without MCAS"), while the NY Times reports:

    "During the early development of the 737 Max, the pilot, Ray Craig, a silver-haired retired Navy airman, was trying out high-speed situations on a flight simulator, like maneuvers to avoid an obstacle or to escape a powerful vortex from another plane. While such moves might never be necessary for the pilot of a passenger plane, the F.A.A. requires that a jet handle well in those situations.

    But the plane wasn’t flying smoothly, partly because of the Max’s bigger engines. To fix the issue, Boeing decided to use a piece of software. The system was meant to work in the background, so pilots effectively wouldn’t know it was there."

    then

    "But a few weeks [after the first 737 Max's maiden flight], [Ed Wilson, the Max's new chief test pilot] and his co-pilot began noticing that something was off, according to a person with direct knowledge of the flights. The Max wasn’t handling well when nearing stalls at low speeds.

    In a meeting at Boeing Field in Seattle, Mr. Wilson told engineers that the issue would need to be fixed. He and his co-pilot proposed MCAS, the person said."

    This expansion of the flight envelope for MCAS activation necessitated removal of the G-Meter "interlock", leading to dependence on the (single) AoA sensor data.
     
  17. Nurburgringer

    Nurburgringer F1 World Champ

    Jan 3, 2009
    11,031
    Texass
    He's giving a mixed message there. Calls the "first iteration" of MCAS "poorly designed and executed" then finishes with "[the 737 changes done only to maintain a single type certificate] illustrates a lack of training and understanding of all the changes the 737 has gone through, especially for a whole new generation of 737 Max pilots".

    Even if the Lion and Ethiopian Air pilots had been trained differently it was still a ****ty system that would actively, repeatedly try to crash the plane if one lone AoA sensor crapped out.
     
    teak360 and Bob Parks like this.
  18. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    37,984
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    Newspapers are the last place I would look for reliable information on technical details on aircraft.
     
    FERRARI-TECH, Jaguar36 and Bob Parks like this.
  19. Nurburgringer

    Nurburgringer F1 World Champ

    Jan 3, 2009
    11,031
    Texass
    Terry - curious what technical details you find incorrect or suspect in the article.

    One thing that bothers me about it is the way "G-force" is described:
    "To ensure it didn’t misfire, engineers initially designed MCAS to trigger when the plane exceeded at least two separate thresholds, according to three people who worked on the 737 Max. One involved the plane’s angle to the wind, and the other involved so-called G-force, or the force on the plane that typically comes from accelerating."
    "Expanding the use of MCAS to lower-speed situations required removing the G-force threshold. MCAS now needed to work at low speeds so G-force didn’t apply."

    I couldn't find any other references online to this G-force measurement being an early input/interlock to the MCAS system, would like to learn more about it.
    Describing g-forces as "typically coming from accelerating" is a strange way to phrase it.
     
  20. Etcetera

    Etcetera Two Time F1 World Champ
    Silver Subscribed

    Dec 7, 2003
    22,177
    Full Name:
    C9H8O4

    The plane actively flew itself into the ground.

    Image Unavailable, Please Login
     
  21. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    37,984
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    N- I did not read it. It is a general statement of who knows what they are talking about. I believe most of what I read in Aviation Week, not much in the NYT, especially on technical subjects.
     
  22. Bob Parks

    Bob Parks F1 Veteran
    Consultant

    Nov 29, 2003
    7,911
    Shoreline,Washington
    Full Name:
    Robert Parks
    Yes, especially when they talk about "G-Force acceleration" and the airplane's angle of wind sensor.That sounds like something that I would say when I am finishing my second scotch.
     
  23. Tcar

    Tcar F1 Rookie

    Sure looks like deploying even a little flaps negates the problem...
    Why not flaps and go-around?
     
  24. Nurburgringer

    Nurburgringer F1 World Champ

    Jan 3, 2009
    11,031
    Texass
    lol only your second scotch?!
    Those funny phrases aside, interviews with ex-Boeing test pilots and engineers, and FAA employees unearthed some very interesting history about the MCAS system. We'lll see how it stacks up against the inevitable Aviation Week article and/or History's Greatest Engineering Failures episode on History channel ;)
     

Share This Page