Reminded me of Asiana 214Originally Posted by entropy
Reminded me of Asiana 214
Showing how little I do know, but are pilots usually used on the FMEAs as reasons why aircraft system issues have mitigation? My work has never allowed me to assume a user can be part of mitigation, but none of my users have ever been trained to the standards of commercial airline pilots. Strict liability forces us to assume that if we can envision a failure mode that we must address it with the design, even if the user is the root cause (misuse).
To me, the MCAS SW has design issues, especially if data from one sensor was not compared to the other. If both sensors are present, it is normal practice to use them for a simple sanity check. If they disagree, my first thought is the SW should flag an error and then execute the proper actions for that error case. Ideally there would be three sensors, two of which have to agree, to provide valid data, but the SW designers need to work with the HW provided. Two is better than one.
Combined with the Bloomberg article on moving the SW to India, I can guess what happened during the SW development. It is very difficult to develop good SW when your SW development team is not present with the systems engineers and the SW management team is not local to the developers. The systems engineers should have caught the issue with using just one AoA sensor. They may have done so and struggled with getting the issue fixed with a SW team on the other side of the world.
I often commute on AA. This summer has been a particularly tough one, so I’m often up front in the jumpseat. Plenty of time to talk shop. From what I’ve been told, AA is pulling the ‘80s out of the desert as fast as they can while attempting to crew them. Definitely some senior guys in DFW making bank on this one.
Working diligently to enlarge my group size.
I only have access to “open source” info (public information), so, without a cockpit voice recorder transcript, I honestly have no idea.
For those interested, an article on MCAS:
https://theaircurrent.com/aviation-s...em-mcas-jt610/
And, the Boeing bulletin issued after the first Max crash:
https://theaircurrent.com/aviation-s...ion-air-crash/
I had no idea that MCAS only worked when the plane was being hand flown, and that it is inactive with the auto pilot on. It is ironic, with the discussion of “magenta pilots,” that if the AP was on, or engaged, it would defeat MCAS. Also interesting, that the Boeing bulletin references leaving the override on, to help trimming the aircraft after MCAS activated.
Likes pretty much everything in every caliber.
Two additional bits of information on this topic:
1. The autopilot will only engage when no force is being applied to the control yoke (which normally implies that the aircraft is in trim). So, while MCAS won’t activate when the autopilot is engaged, it isn’t likely that a pilot could engage the autopilot to make MCAS stop adding nose-down trim.
2. Pilots who are dependent on the autopilot (I believe the procedure for both mishap airlines was to engage autopilot at 500 ft on takeoff) are less likely to be proficient at hand-flying. So, when MCAS activated shortly after takeoff, they were unable to engage the autopilot, and likely lacked skill and experience hand-flying the aircraft.
Yes, leaving the stab trim active until the MCAS inputs were countered (trimmed out) would make sense. Then activate stab trim cutout switch to prevent additional MCAS inputs.
I must have been a forceps baby - as a paying customer, I still miss AA’s 80/83 fleet.
Ken
BBI: ...”you better not forget the safe word because shit's about to get weird”...
revchuck38: ...”mo' ammo is mo' betta' unless you're swimming or on fire.”
There are a whole bucket of questions I have about MCAS. Aircraft Certification is a dark art where engineering and bureaucracy meet and I don't pretend to understand anything but the basics. Much of the blame for the fiasco of MCAS has been thrown at the airlines and Boeing for wanting to minimize the training required to transition from the Classic and NexGen 737s to the Max (called differences training in the lingo) and to above all - keep the Max on the same "Type Rating" as the rest of the 737 fleet. The Type Rating thing has be baffled as there are many other aircraft "Types" that share the same rating that are FAR FAR FAR more different from each other than the Max is from the 737NG (or Classic for that matter). Examples include the 767/757, CRJ, and DC9 (which allows you to go from short stubby all steam guaged -10 all the way to a full glass stretched MD-90 with more flaps and stuff hanging off it than a gypsy wagon).
The funny thing is that despite what "Sully The Magnificent" says (when he is not urging people to vote for Democrats), the training on MCAS would have taken only a few minutes and cost EVERYONE a whole lot less than this fiasco has. The Max story has to be the ultimate cautionary tail of spending a fortune to try and save a penny.
I'm not sure if this article has been posted here, but despite it being a NYT article - it is a pretty good piece and does a better job of explaining the decision tree that lead to MCAS being implemented the way it was. https://www.nytimes.com/2019/06/01/b...max-crash.html
This is coming from a guy who has I assume well North of a couple 1000 hours flying light planes in Alaska as well as some rotor time (going by your previous posts). You sir are the exception to the rule as are most US pilots. In the rest of the world there is very little in the way of general aviation where young pilots fly for hundreds or thousands of hours before they get a chance to fly a beat up twin hauling freight before they get a chance to fly a commuter for a few more thousand hours before ending up in the right seat of a 737.
In the parts of the world these accidents occurred - the pilots are given the MINIMUM amount of time in light aircraft required to meet ICAO or local requirements. That means as little a 250 hours in light aircraft before they are sitting in the cockpit of a large transport airplane. Then for the rest of their flying career they will be engaging the autopilot at 500 feet and keeping it on until they reach minimums (unless they are doing an autoland). The thought of hand flying is both foreign and terrifying to them. In addition - many foreign countries issue what are known as MultiCrew Licenses which basically mean that their flying privileges are only applicable when operating in a multi-crew environment. So that first officer on the 777 you are taking across the ocean, well he wouldn't be able to walk into an FBO and fly a Cessna 152 on his own.
I flight instructed at a school that did the initial flight training for 3 major Asian airlines. In addition we did the initial flight training for many Asians and Europeans who were just needing to get their tickets. The stories I could tell.......... Basic things like kids from China having never driven a car not understanding the simple concept of slowing down before you try to take a sharp turn! Another is a story of a little guy form Indonesia who was a very weak student (physically as well as from a aviation standpoint). He had an uncle who owned an airline in Indonesia and all he needed to get was his CMEL rating. One day he was with his instructor doing multi-engine approaches and when told to go around on a touch and go - only advanced one throttle. The airplane did a VMC demo at 5 feet and cartwheeled. Miraculously they both survived! The FAA did their investigation and his instructor had to go through a whole string of rides to be able to instruct again, our Indonesian friend just found another school. I looked him up on FB a while back - he is a Captain on an A320. His instructor (who I keep contact with) just landed a job at a US major as a FO almost 20 years after the accident.
Last edited by Suvorov; 07-03-2019 at 02:35 PM.
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