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posted by martyb on Tuesday April 09 2019, @11:03AM   Printer-friendly
from the pulled-the-handbrake-as-hard-as-I-could dept.

A 2018 FAA (Federal Aviation Administration directive advised pilots to handle MCAS (Maneuvering Characteristics Augmentation System) failure by disabling electric control of stabilizer trim using a pair of cutout switches. Pilots would then need to use a hand crank to move the stabilizer back to the desired position. It's noted that previous 737 models had separate switches to disable autopilot and electric stabilizer control, but the 737 MAX lacked this distinction.

Avionics engineer Peter Lemme explains how aerodynamic forces acting on the stabilizer and elevator in a nose-down situation would oppose pilots' attempts to correct the trim using their manual control.

A 1982 Boeing 737-200 Pilot Training Manual acknowledges this possibility, describing a series of maneuvers which can be used to relieve force on the controls and allow incremental correction of trim. However, it's suggested that the Ethiopian Airline plane had already gained too much speed and lost too much altitude for such a maneuver to be possible.

https://www.moonofalabama.org/2019/04/ethiopian-airline-crash-boeing-and-faa-advice-to-737-max-pilots-was-insufficient-and-flawed.html
https://www.satcom.guru/2019/04/stabilizer-trim-loads-and-range.html


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  • (Score: 0) by Anonymous Coward on Tuesday April 09 2019, @03:27PM (2 children)

    by Anonymous Coward on Tuesday April 09 2019, @03:27PM (#826821)

    No biggie,

    It's actually the largest "biggie" they have. If they calculate the risks wrong, like actuarial tables and they are providing life insurance, then they can get royally fucked as the payouts starts rolling while they collected much less in premiums. There is no retroactive premiums!

    temporary loss is a nice tax deduction written into the code just for them.

    Ok, so I'm sure you never really run any business, *ever*. Having a loss is not exactly good for the business.

  • (Score: 0) by Anonymous Coward on Tuesday April 09 2019, @04:19PM

    by Anonymous Coward on Tuesday April 09 2019, @04:19PM (#826868)

    There is no retroactive premiums!

    The costs are spread around the customer base. That's how shit works

    Ok, so I'm sure you never really run any business, *ever*.

    Yeah, and I'm sure you're talking out yer ass. The occasional loss is to be expected, and can easily be covered elsewhere. You really are full of it...

  • (Score: 2) by bob_super on Tuesday April 09 2019, @05:11PM

    by bob_super (1357) on Tuesday April 09 2019, @05:11PM (#826907)

    > they can get royally fucked as the payouts starts rolling while they collected much less in premiums.

    If only anyone had thought of that problem before ...
    https://en.wikipedia.org/wiki/Reinsurance [wikipedia.org]