Wow, Beiber. This is as close a dissection of the MAX-737 issue as I have read or heard anywhere. Sounds criminal to have not used redundancy in the sensors, especially in civil aviation with so many lives at stake on a trip. Human complacency takes over, I guess, when something works so well for so long. The lifting torque you mention was of the yaw kind or roll kind?
On Sat, Jul 6, 2019, 12:28 AM Dennis Lee Bieber <[email protected]> wrote: > On Fri, 5 Jul 2019 16:41:40 +0000 (UTC), "'Mark Lazarewicz' via > BeagleBoard" <[email protected]> > declaimed the following: > > >It's shoddy psuedo engineer's like that the caused people to be Killed on > Boeing 737 max software outsourced to sub standard engineeers I know I > worked with them lots of nodding and smiling no substance. > > From what I've read, some test bed software, and maybe some display > software was outsourced. NOT the flight management software -- which has > been produced by GE Aviation (formerly Smiths Aerospace, nee Lear-Siegler) > for quite some time on the 737. {I supported the "BootROM" of the 737 > flight computers for four years -- BootROM runs the memory/processor > self-checks, and determines which application (dataloader, flight > management, etc.) is to be started based upon external sensors (no > dataloader if the wheels are not on ground <G>). The flight software for > the boxes was produced in the cubicle farm on the other side of the > building from mine.} > > The gist I have for this fiasco is that shoddy requirements were in > play -- defining the MCAS system to be a "transparent" addition to the > software (one description I've read describes MCAS as being meant to > compensate for the different lift characteristics of the MAX when angle of > attack varies. The MAX engines are so large that they are mounted much more > forward from the wing, and higher -- as a result, when not directly aimed > into the air flow (as in climbs), the engine nacelle created a lifting > torque in front of the wing. MCAS was supposed to counter that torque so > pilots "feet" the plane behaving the same as non-MAX 737 models. However, > MCAS relied upon single sensor (and apparently did not have left/right > redundancy) -- the multi-sensor configuration was "optional" on the order > form. > > Because MCAS was supposed to be "transparent", pilots were not > supposed > to need updated training. It was also added to the flight software in a way > to minimize how much of the flight software (most of which has been flying > for decades on 737 models) had to be re-certified... > > > -- > Wulfraed Dennis Lee Bieber AF6VN > [email protected] > http://wlfraed.microdiversity.freeddns.org/ > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/he6vhe9g1pd04iq16e8fcodrgdv9fnnpa3%404ax.com > . > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAHW0bcyZ4Gb7V2-%3DH21FGa6dPATnBohpdgAg%3DRwv%2BAjGnwi98g%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
